text
stringlengths 6
1.88M
| source
stringclasses 13
values |
|---|---|
bic tcp bic tcp binary increase congestion control one congestion control algorithms used transmission control protocol tcp bic optimized high speed networks high latency so-called long fat networks networks bic significant advantage previous congestion control schemes correcting severely underutilized bandwidth bic implements unique congestion window cwnd algorithm algorithm tries find maximum cwnd searching three parts binary search increase additive increase slow start network failure occurs bic uses multiplicative decrease correcting cwnd bic tcp implemented used default linux kernels 2.6.8 default implementation changed cubic tcp 2.6.19 version define following variables every rtt interval update cwnd following packets dropped congestion window cwnd increases three distinct ways binary search increase additive increase slow start step one used increment one step increasing cwnd one packets dropped cwnd reduced using multiplicative decrease requires ฮฒ used decreasing cwnd 100รฮฒ case two flows one large cwnd small cwnd fast convergence used decrease greater cwnd flow w greater rate smaller cwnd flow allow faster convergence greater cwnd flow increasing cwnd one step decreasing cwnd
|
Internet protocols
|
microsoft foundation class library microsoft foundation class library mfc c++ object-oriented library developing desktop applications windows mfc introduced microsoft 1992 quickly gained widespread use microsoft introduced alternative application frameworks since mfc remains widely used mfc introduced 1992 microsoft c/c++ 7.0 compiler use 16-bit versions windows extremely thin object-oriented c++ wrapper windows api c++ beginning replace c development commercial application software time mfc program direct windows api calls rarely needed instead programs create objects microsoft foundation class classes call member functions belonging objects many functions share names corresponding api functions one quirk mfc use afx prefix many functions macros standard precompiled header name stdafx.h early development became mfc called application framework extensions abbreviated afx name microsoft foundation classes mfc adopted late release cycle change references mfc 8.0 released visual studio 2005 mfc 9.0 released visual studio 2008 april 7 2008 microsoft released update mfc classes out-of-band update visual studio 2008 mfc 9 update features new user interface constructs including ribbons associated ui widgets fully customizable toolbars docking panes either freely floated docked side document tabs mfc initially feature commercial versions visual studio included freeware visual c++ express community edition visual studio introduced 2014 however includes mfc object windows library owl designed use borland turbo c++ compiler competing product introduced borland around time eventually borland discontinued owl development licensed distribution mfc headers libraries dlls microsoft short time though never offered fully integrated support mfc borland later released visual component library replace owl framework mfc library wraps portions windows api c++ classes including functionality enables use default application framework classes defined many handle-managed windows objects also predefined windows common controls time introduction mfc provided c++ macros windows message-handling via message maps exceptions run-time type identification rtti serialization dynamic class instantiation macros message-handling aimed reduce memory consumption avoiding gratuitous virtual table use also provide concrete structure various visual c++-supplied tools edit manipulate code without parsing full language message-handling macros replaced virtual function mechanism provided c++ macros serialization exceptions rtti predated availability features microsoft c++ number years 32-bit versions mfc windows nt 3.1 later windows operating systems used compilers implemented language features updated macros simply wrap language features instead providing customized implementations realizing upward compatibility mfc ribbon resource editor allows developer design ribbon graphically instead use xml-based declarative markup like ribbonx api optionally ribbon components may programmed directly calling new set ribbon class methods developer may mix graphical programmatic ribbon development convenient mfc application wizard also upgraded support new features including check-box select whether application use ribbon docking panes new functionality provided new classes old applications still continue run update building top bcgsoft โ bcgcontrolbar library professional edition microsoft imposed additional licensing requirements users ribbons include requirement adhere microsoft ui design guidelines anti-competition clause prohibiting use ui applications compete microsoft office mfc used linking static library adding mfc dll
|
Operating systems
|
zen bound zen bound puzzle game ios android maemo platforms nokia n900 developed secret exit announced september 5 2008 via company discussion board officially released via app store february 24 2009 via ovi store june 16 2010 port android announced part humble bundle android 2 march 19 2012 game received press attention unique gameplay lite version game also released free featured 2 levels game goal game paint various objects level player given object attached rope varies length depending level using mouse touch screen tilt controls player attempts wrap object rope time rope laid object area near rope gets covered paint challenge getting required percentage object painted finite length rope three targets level minimum medium maximum coverage levels require nails protruding objects entwined rope rather cover object surface 5th imgawards international mobile gaming awards 2008 excellence 3d game extremely well received reviews upon release following review scores websites pocketgamer 10/10 platinum award ign 9.5/10 slidetoplay 4/4 time game highest rated gamerankings.com score 97.86 overtaken grand theft auto v 2014
|
Operating systems
|
columbitech columbitech founded 2000 provides wireless security secure mobile devices support wlan public networks including 3g 4g wimax company headquartered stockholm sweden offices new york city columbitech mobile vpn provides remote network access field mobility users corporate wlan users telecommuters โ mobilizing enterprise solution encrypted standards-based wireless transport layer security wtls holds fips 140-2 certification technology utilized retail industry meet pci dss requirements industries mobile devices used wireless networks
|
Computer security
|
slenfbot slenfbot classification family malicious software malware infects files microsoft windows systems slenfbot first discovered 2007 since numerous variants followed slightly different characteristics new additions worm payload ability provide attacker unauthorized access compromised host slenfbot primarily spreads luring users follow links websites contain malicious payload slenfbot propagates via instant messaging applications removable drives and/or local network via network shares code slenfbot appears closely managed may provide attribution single group and/or indicate large portion code shared amongst multiple groups inclusion malware families variants well continuous evolution makes slenfbot highly effective downloader propensity cause even damage compromised systems majority antivirus a/v vendors use following naming conventions referring family malware end names wildcard possible classifications and/or distinctions malware family none publicly known slenfbot worm spreads using links websites containing malicious software malware via instant messaging programs may include msn/windows live messenger aol instant messenger aim yahoo messenger google chat facebook chat icq skype worm propagates automatically via removable drives shares local network windows file sharing service i.e. server lanmanserver service slenfbot also contains backdoor capabilities allow unauthorized access affected machine. ref name= microsoft_win32/slenfbot /ref ref name= microsoft_worm win32/stekct.a /ref ref name= microsoft_worm win32/stekct.b /ref ref name= win32/slenfbot-just_another_irc_bot /ref ref name= ca_win32/slenfbot /ref ref name= win32/slenfbot.ad /ref code appears closely controlled may provide attribution one group and/or malware authors share significant portion code slenfbot seen wild since 2007 obtained new features capabilities time subsequent variants systematically gained similar feature sets slenfbot continues operate effective infector dynamic downloader additional malware thus making highly functional delivery mechanism spyware information stealers spam bots well malware executed slenfbot copies duplicate malicious payload system folder filename varies per particular variant sets attributes copy read hidden system hide contents windows explorer worm makes changes registry maintain persistence malware executes duplicate copy subsequent startup system e.g copying malicious executable hklm\software\microsoft\windows\currentversion\run subkey several variants may modify registry installation add malware list applications authorized access internet thus allowing malware communicate without raising windows security alerts run unimpeded windows firewall cases variants may instead modify registry install malicious payload debugger benign system file ctfmon.exe ctfmon.exe executes system startup leads execution malware cases slenfbot attempt delete original copy worm variants may make additional modifications registry order delete originally executed copy worm system restarts slenfbot variants may initial execution test see msn/windows live messenger currently running looking window class name msblwindowclass worm finds window malware may display fake error message slenfbot launched removable drive variants may open windows explorer display contents affected drive certain slenfbot variants may inject thread explorer.exe periodically checks presence malware system folder file found malware downloads new copy specified server launches new copy slenfbot uses instant messaging attack vector spread worm accounts contacts remote attacker may use worm โ backdoor capabilities instruct slenfbot spread via msn/windows live messenger aol instant messenger aim yahoo messenger google chat facebook chat icq skype worm connects remote server sends copy url contains list possible messages send randomly creates zip archive contains copy malware sends zip archive instant messaging client contacts following examples messages worm may spread zip file includes file name slenfbot executable may also contain url file download situations attacker instructs worm send arbitrary file slenfbot may spread removable drives creating directory called โ recycler โ root directory removable drive malware create subdirectory โ recycler โ folder e.g โ s-1-6-21-1257894210-1075856346-012573477-2315 โ copy malicious payload directory using different name executable e.g โ folderopen.exe โ slenfbot may also create autorun.inf file root directory drive worm may execute drive connected another system certain variants may download updated copy slenfbot location specified worm write file directory e.g using name โ ~secure โ locations worm copies slenfbot sets hidden system attributes respective directories files circumstances due programming issue slenfbot may create one directory rather two e.g โ e \recyclers-1-6-21-1257894210-1075856346-012573477-2315\folderopen.exe โ slenfbot may spread accessible shares upon successful compromise system worm may also spread file print shares exploiting known vulnerabilities ms06-040 ms10-061 pertain issues server print spooler services respectively attacker would instruct worm spread remote system via exploit instant messaging order continue propagation slenfbot following steps may help prevent infection slenfbot uses stealth measures maintain persistence system thus may need boot trusted environment order remove slenfbot may also make changes computer changes windows registry makes difficult download install and/or update virus protection also since many variants slenfbot attempt propagate available removable/remote drives network shares important ensure recovery process thoroughly detects removes malware known/possible locations one possible solution would use microsoft โ windows defender offline beta detect remove slenfbot system information windows defender offline go http //windows.microsoft.com/en-us/windows/what-is-windows-defender-offline
|
Computer security
|
graphics processing unit graphics processing unit gpu specialized electronic circuit designed rapidly manipulate alter memory accelerate creation images frame buffer intended output display device gpus used embedded systems mobile phones personal computers workstations game consoles modern gpus efficient manipulating computer graphics image processing highly parallel structure makes efficient general-purpose central processing units cpus algorithms process large blocks data parallel personal computer gpu present video card embedded motherboard certain cpus embedded cpu die term gpu coined sony reference playstation console toshiba-designed sony gpu 1994 term popularized nvidia 1999 marketed geforce 256 world first gpu presented single-chip processor integrated transform lighting triangle setup/clipping rendering engines rival ati technologies coined term visual processing unit vpu release radeon 9700 2002 arcade system boards using specialized graphics chips since 1970s early video game hardware ram frame buffers expensive video chips composited data together display scanned monitor fujitsu mb14241 video shifter used accelerate drawing sprite graphics various 1970s arcade games taito midway gun fight 1975 sea wolf 1976 space invaders 1978 namco galaxian arcade system 1979 used specialized graphics hardware supporting rgb color multi-colored sprites tilemap backgrounds galaxian hardware widely used golden age arcade video games game companies namco centuri gremlin irem konami midway nichibutsu sega taito home market atari 2600 1977 used video shifter called television interface adaptor atari 8-bit computers 1979 antic video processor interpreted instructions describing display list โthe way scan lines map specific bitmapped character modes memory stored need contiguous frame buffer 6502 machine code subroutines could triggered scan lines setting bit display list instruction antic also supported smooth vertical horizontal scrolling independent cpu nec ยตpd7220 first implementation pc graphics display processor single large scale integration lsi integrated circuit chip enabling design low-cost high-performance video graphics cards number nine visual technology became best known graphics processing unit mid-1980s first fully integrated vlsi large-scale integration metal-oxide-semiconductor nmos graphics display processor pcs supported 1024x1024 resolution laid foundations emerging pc graphics market used number graphics cards licensed clones intel 82720 first intel graphics processing units williams electronics arcade games robotron 2084 joust sinistar bubbles released 1982 contain custom blitter chips operating 16-color bitmaps 1984 hitachi released artc hd63484 first major cmos graphics processor pc artc capable displaying 4k resolution monochrome mode used number pc graphics cards terminals late 1980s 1985 commodore amiga featured custom graphics chip blitter unit accelerating bitmap manipulation line draw area fill functions also included coprocessor simple instruction set capable manipulating graphics hardware registers sync video beam e.g per-scanline palette switches sprite multiplexing hardware windowing driving blitter 1986 texas instruments released tms34010 first fully programmable graphics processor could run general-purpose code graphics-oriented instruction set 1990-1992 chip would become basis texas instruments graphics architecture tiga windows accelerator cards 1987 ibm 8514 graphics system released one first video cards ibm pc compatibles implement fixed-function 2d primitives electronic hardware sharp x68000 released 1987 used custom graphics chipset 65,536 color palette hardware support sprites scrolling multiple playfields eventually serving development machine capcom cp system arcade board fujitsu later competed fm towns computer released 1989 support full 16,777,216 color palette 1988 first dedicated polygonal 3d graphics boards introduced arcades namco system 21 taito air system ibm proprietary video graphics array vga display standard introduced 1987 maximum resolution 640ร480 pixels november 1988 nec home electronics announced creation video electronics standards association vesa develop promote super vga svga computer display standard successor ibm proprietary vga display standard super vga enabled graphics display resolutions 800ร600 pixels 36 increase 1991 s3 graphics introduced s3 86c911 designers named porsche 911 indication performance increase promised 86c911 spawned host imitators 1995 major pc graphics chip makers added 2d acceleration support chips time fixed-function windows accelerators surpassed expensive general-purpose graphics coprocessors windows performance coprocessors faded away pc market throughout 1990s 2d gui acceleration continued evolve manufacturing capabilities improved level integration graphics chips additional application programming interfaces apis arrived variety tasks microsoft wing graphics library windows 3.x later directdraw interface hardware acceleration 2d games within windows 95 later early- mid-1990s real-time 3d graphics becoming increasingly common arcade computer console games led increasing public demand hardware-accelerated 3d graphics early examples mass-market 3d graphics hardware found arcade system boards sega model 1 namco system 22 sega model 2 fifth-generation video game consoles saturn playstation nintendo 64 arcade systems sega model 2 namco magic edge hornet simulator 1993 capable hardware l transform clipping lighting years appearing consumer graphics cards systems used dsps accelerate transformations fujitsu worked sega model 2 arcade system began working integrating l single lsi solution use home computers 1995 fujitsu pinolite first 3d geometry processor personal computers released 1997 first hardware l gpu home video game consoles nintendo 64 reality coprocessor released 1996 1997 mitsubishi released 3dpro/2mp fully featured gpu capable transformation lighting workstations windows nt desktops ati utilized firegl 4000 graphics card released 1997 term gpu coined sony reference 32-bit sony gpu designed toshiba playstation video game console released 1994 pc world notable failed first tries low-cost 3d graphics chips s3 virge ati rage matrox mystique chips essentially previous-generation 2d accelerators 3d features bolted many even pin-compatible earlier-generation chips ease implementation minimal cost initially performance 3d graphics possible discrete boards dedicated accelerating 3d functions lacking 2d gui acceleration entirely powervr 3dfx voodoo however manufacturing technology continued progress video 2d gui acceleration 3d functionality integrated one chip rendition verite chipsets among first well enough worthy note 1997 rendition went step collaborating hercules fujitsu thriller conspiracy project combined fujitsu fxg-1 pinolite geometry processor vรฉritรฉ v2200 core create graphics card full l engine years nvidia geforce 256 card designed reduce load placed upon system cpu never made market opengl appeared early '90s professional graphics api originally suffered performance issues allowed glide api step become dominant force pc late '90s however issues quickly overcome glide api fell wayside software implementations opengl common time although influence opengl eventually led widespread hardware support time parity emerged features offered hardware offered opengl directx became popular among windows game developers late 90s unlike opengl microsoft insisted providing strict one-to-one support hardware approach made directx less popular standalone graphics api initially since many gpus provided specific features existing opengl applications already able benefit leaving directx often one generation behind see comparison opengl direct3d time microsoft began work closely hardware developers started target releases directx coincide supporting graphics hardware direct3d 5.0 first version burgeoning api gain widespread adoption gaming market competed directly many more-hardware-specific often proprietary graphics libraries opengl maintained strong following direct3d 7.0 introduced support hardware-accelerated transform lighting l direct3d opengl capability already exposed inception 3d accelerator cards moved beyond simple rasterizers add another significant hardware stage 3d rendering pipeline nvidia geforce 256 also known nv10 first consumer-level card released market hardware-accelerated l professional 3d cards already capability hardware transform lighting already existing features opengl came consumer-level hardware '90s set precedent later pixel shader vertex shader units far flexible programmable nvidia first produce chip capable programmable shading geforce 3 code named nv20 pixel could processed short program could include additional image textures inputs geometric vertex could likewise processed short program projected onto screen used xbox console competed playstation 2 used custom vector dsp hardware accelerated vertex processing commonly referred vu0/vu1 earliest incarnations shader execution engines used xbox general purpose could execute arbitrary pixel code vertices pixels processed different units resources pixel shaders much tighter constraints executed much higher frequencies vertices pixel shading engines actually akin highly customizable function block n't really run program many disparities vertex pixel shading would n't addressed much later unified shader model october 2002 introduction ati radeon 9700 also known r300 world first direct3d 9.0 accelerator pixel vertex shaders could implement looping lengthy floating point math quickly becoming flexible cpus yet orders magnitude faster image-array operations pixel shading often used bump mapping adds texture make object look shiny dull rough even round extruded introduction geforce 8 series produced nvidia new generic stream processing unit gpus became generalized computing device today parallel gpus begun making computational inroads cpu subfield research dubbed gpu computing gpgpu general purpose computing gpu found way fields diverse machine learning oil exploration scientific image processing linear algebra statistics 3d reconstruction even stock options pricing determination gpgpu time precursor call compute shaders e.g cuda opencl directcompute actually abused hardware degree treating data passed algorithms texture maps executing algorithms drawing triangle quad appropriate pixel shader obviously entails overheads since involve units like scan converter n't really needed even care triangles except invoke pixel shader years energy consumption gpus increased manage several techniques proposed nvidia cuda platform first introduced 2007 earliest widely adopted programming model gpu computing recently opencl become broadly supported opencl open standard defined khronos group allows development code gpus cpus emphasis portability opencl solutions supported intel amd nvidia arm according recent report evan data opencl gpgpu development platform widely used developers us asia pacific 2010 nvidia began partnership audi power cars dashboards tegra gpus powering cars dashboard offering increased functionality cars navigation entertainment systems advancements gpu technology cars helped push self-driving technology amd radeon hd 6000 series cards released 2010 2011 amd released 6000m series discrete gpus used mobile devices kepler line graphics cards nvidia came 2012 used nvidia 600 700 series cards new feature new gpu microarchitecture included gpu boost technology adjusts clock-speed video card increase decrease according power draw kepler microarchitecture manufactured 28 nm process ps4 xbox one released 2013 use gpus based amd radeon hd 7850 7790 nvidia kepler line gpus followed maxwell line manufactured process 28 nm chips nvidia manufactured tsmc taiwan semiconductor manufacturing company manufacturing using 28 nm process time compared 40 nm technology past new manufacturing process allowed 20 percent boost performance drawing less power virtual reality headsets high system requirements vr headset manufacturers recommended gtx 970 r9 290x better time release pascal next generation consumer graphics cards nvidia released 2016 geforce 10 series cards generation graphics cards made using 16 nm manufacturing process improves upon previous microarchitectures nvidia released one non-consumer card new volta architecture titan v. changes titan xp pascal high-end card include increase number cuda cores addition tensor cores hbm2 tensor cores cores specially designed deep learning high-bandwidth memory on-die stacked lower-clocked memory offers extremely wide memory bus useful titan v intended purpose emphasize titan v gaming card nvidia removed geforce gtx suffix adds consumer gaming cards new generation rtx turing gpus unveiled august 20 2018 add ray-tracing cores gpus improving performance lighting effects polaris 11 polaris 10 gpus amd fabricated 14-nanometer process release results substantial increase performance per watt amd video cards amd also released vega gpus series high end market competitor nvidia high end pascal cards also featuring hbm2 like titan v. many companies produced gpus number brand names 2009 intel nvidia amd/ati market share leaders 49.4 27.8 20.6 market share respectively however numbers include intel integrated graphics solutions gpus counting nvidia amd control nearly 100 market 2018 respective market shares 66 33 addition s3 graphics matrox produce gpus modern smartphones also using mostly adreno gpus qualcomm powervr gpus imagination technologies mali gpus arm modern gpus use transistors calculations related 3d computer graphics addition 3d hardware today gpus include basic 2d acceleration framebuffer capabilities usually vga compatibility mode newer cards like amd/ati hd5000-hd7000 even lack 2d acceleration emulated 3d hardware gpus initially used accelerate memory-intensive work texture mapping rendering polygons later adding units accelerate geometric calculations rotation translation vertices different coordinate systems recent developments gpus include support programmable shaders manipulate vertices textures many operations supported cpus oversampling interpolation techniques reduce aliasing high-precision color spaces computations involve matrix vector operations engineers scientists increasingly studied use gpus non-graphical calculations especially suited embarrassingly parallel problems emergence deep learning importance gpus increased research done indigo found training deep learning neural networks gpus 250 times faster cpus explosive growth deep learning recent years attributed emergence general purpose gpus level competition area asics prominently tensor processing unit tpu made google however require changes existing code gpus still popular gpus made since 1995 support yuv color space hardware overlays important digital video playback many gpus made since 2000 also support mpeg primitives motion compensation idct process hardware accelerated video decoding portions video decoding process video post-processing offloaded gpu hardware commonly referred gpu accelerated video decoding gpu assisted video decoding gpu hardware accelerated video decoding gpu hardware assisted video decoding recent graphics cards even decode high-definition video card offloading central processing unit common apis gpu accelerated video decoding dxva microsoft windows operating system vdpau vaapi xvmc xvba linux-based unix-like operating systems except xvmc capable decoding videos encoded mpeg-1 mpeg-2 mpeg-4 asp mpeg-4 part 2 mpeg-4 avc h.264 divx 6 vc-1 wmv3/wmv9 xvid opendivx divx 4 divx 5 codecs xvmc capable decoding mpeg-1 mpeg-2 video decoding processes accelerated today modern gpu hardware personal computers two main forms gpus many synonyms gpus designed specific usage real-time 3d graphics mass calculations gpus powerful class typically interface motherboard means expansion slot pci express pcie accelerated graphics port agp usually replaced upgraded relative ease assuming motherboard capable supporting upgrade graphics cards still use peripheral component interconnect pci slots bandwidth limited generally used pcie agp slot available dedicated gpu necessarily removable necessarily interface motherboard standard fashion term dedicated refers fact dedicated graphics cards ram dedicated card use fact dedicated gpus removable ram usually specially selected expected serial workload graphics card see gddr sometimes systems dedicated discrete gpus called dis systems opposed uma systems see next section dedicated gpus portable computers commonly interfaced non-standard often proprietary slot due size weight constraints ports may still considered pcie agp terms logical host interface even physically interchangeable counterparts technologies sli nvidia crossfire amd allow multiple gpus draw images simultaneously single screen increasing processing power available graphics integrated graphics processing unit igpu integrated graphics shared graphics solutions integrated graphics processors igp unified memory architecture uma utilize portion computer system ram rather dedicated graphics memory igps integrated onto motherboard part chipset die cpu like amd apu intel hd graphics certain motherboards amd igps use dedicated sideport memory separate fixed block high performance memory dedicated use gpu early 2007 computers integrated graphics account 90 pc shipments less costly implement dedicated graphics processing tend less capable historically integrated processing often considered unfit play 3d games run graphically intensive programs could run less intensive programs adobe flash examples igps would offerings sis via circa 2004 however modern integrated graphics processors amd accelerated processing unit intel hd graphics capable handling 2d graphics low stress 3d graphics gpu extremely memory intensive integrated processing may find competing cpu relatively slow system ram minimal dedicated video memory igps 29.856 gb/s memory bandwidth system ram whereas graphics card may 264 gb/s bandwidth ram gpu core memory bus bandwidth limit performance gpu though multi-channel memory mitigate deficiency older integrated graphics chipsets lacked hardware transform lighting newer ones include newer class gpus competes integrated graphics low-end desktop notebook markets common implementations ati hypermemory nvidia turbocache hybrid graphics cards somewhat expensive integrated graphics much less expensive dedicated graphics cards share memory system small dedicated memory cache make high latency system ram technologies within pci express make possible solutions sometimes advertised much 768mb ram refers much shared system memory becoming increasingly common use general purpose graphics processing unit gpgpu modified form stream processor vector processor running compute kernels concept turns massive computational power modern graphics accelerator shader pipeline general-purpose computing power opposed hard wired solely graphical operations certain applications requiring massive vector operations yield several orders magnitude higher performance conventional cpu two largest discrete see dedicated graphics cards gpu designers amd nvidia beginning pursue approach array applications nvidia amd teamed stanford university create gpu-based client folding home distributed computing project protein folding calculations certain circumstances gpu calculates forty times faster conventional cpus traditionally used applications gpgpu used many types embarrassingly parallel tasks including ray tracing generally suited high-throughput type computations exhibit data-parallelism exploit wide vector width simd architecture gpu furthermore gpu-based high performance computers starting play significant role large-scale modelling three 10 powerful supercomputers world take advantage gpu acceleration gpu supports api extensions c programming language opencl openmp furthermore gpu vendor introduced api works cards amd app sdk cuda amd nvidia respectively technologies allow specified functions called compute kernels normal c program run gpu stream processors makes possible c programs take advantage gpu ability operate large buffers parallel still using cpu appropriate cuda also first api allow cpu-based applications directly access resources gpu general purpose computing without limitations using graphics api since 2005 interest using performance offered gpus evolutionary computation general accelerating fitness evaluation genetic programming particular approaches compile linear tree programs host pc transfer executable gpu run typically performance advantage obtained running single active program simultaneously many example problems parallel using gpu simd architecture however substantial acceleration also obtained compiling programs instead transferring gpu interpreted acceleration obtained either interpreting multiple programs simultaneously simultaneously running multiple example problems combinations modern gpu readily simultaneously interpret hundreds thousands small programs modern workstation gpus nvidia quadro workstation cards using volta turing architectures feature dedicating processing cores tensor-based deep learning applications nvidia current series gpus cores called tensor cores gpus usually significant flops performance increases utilizing 4x4 matrix multiplication division resulting hardware performance 128 tflops applications tensor cores also supposed appear consumer cards running turing architecture possibly navi series consumer cards amd external gpu graphics processor located outside housing computer external graphics processors sometimes used laptop computers laptops might substantial amount ram sufficiently powerful central processing unit cpu often lack powerful graphics processor instead less powerful energy-efficient on-board graphics chip on-board graphics chips often powerful enough playing latest games graphically intensive tasks editing video therefore desirable able attach gpu external bus notebook pci express bus commonly used purpose port may example expresscard mpcie port pcie ร1 5 2.5 gbit/s respectively thunderbolt 1 2 3 port pcie ร4 10 20 40 gbit/s respectively ports available certain notebook systems official vendor support external gpus gained traction recently one notable milestone apple โ decision officially support external gpus mac os high sierra 10.13.4 also several major hardware vendors hp alienware razer releasing thunderbolt 3 egpu enclosures support continued fuel egpu implementations enthusiasts 2013 438.3 million gpus shipped globally forecast 2014 414.2 million
|
Computer architecture
|
constrained application protocol constrained application protocol coap specialized internet application protocol constrained devices defined rfc 7252 enables constrained devices called nodes communicate wider internet using similar protocols coap designed use devices constrained network e.g. low-power lossy networks devices general nodes internet devices different constrained networks joined internet coap also used via mechanisms sms mobile communication networks coap service layer protocol intended use resource-constrained internet devices wireless sensor network nodes coap designed easily translate http simplified integration web also meeting specialized requirements multicast support low overhead simplicity multicast low overhead simplicity extremely important internet things iot machine-to-machine m2m devices tend deeply embedded much less memory power supply traditional internet devices therefore efficiency important coap run devices support udp udp analogue internet engineering task force ietf constrained restful environments working group core done major standardization work protocol order make protocol suitable iot m2m applications various new functionalities added core protocol specified rfc 7252 important extensions various stages standardization process nodes often 8-bit microcontrollers small amounts rom ram constrained networks ipv6 low-power wireless personal area networks 6lowpans often high packet error rates typical throughput 10s kbit/s protocol designed machine-to-machine m2m applications smart energy building automation core group designed coap following features mind mapping coap http also defined allowing proxies built providing access coap resources via http uniform way introduction coap complete networking stack open-standard protocols suitable constrained devices environments becomes available architecture point view coap server installed end node could sensor hand coap client installed controller manages several end nodes registration meanings behind coap code options content type handled iana shown smallest coap message 4 bytes length omitting token options payload coap makes use two message types requests responses using simple binary base header format base header may followed options optimized type-length-value format coap default bound udp optionally dtls providing high level communications security bytes headers packet considered message body length message body implied datagram length bound udp entire message must fit within single datagram used 6lowpan defined rfc 4944 messages fit single ieee 802.15.4 frame minimize fragmentation three significant bits form number known class analogous class http status codes five least significant bits form code communicates detail request response entire code typically communicated form codice_1 find latest coap request/response codes though list gives examples easily extract information fixed header c via macros many coap application domains essential ability address several coap resources group instead addressing resource individually e.g turn coap-enabled lights room single coap request triggered toggling light switch address need ietf developed optional extension coap form experimental rfc group communication coap rfc 7390 extension relies ip multicast deliver coap request group members use multicast certain benefits reducing number packets needed deliver request members however multicast also limitations poor reliability cache-unfriendly alternative method coap group communication uses unicasts instead multicasts relies intermediary groups created clients send group requests intermediary turn sends individual unicast requests group members collects replies sends back aggregated reply client although protocol standard includes provisions mitigating threat ddos amplification attacks provisions implemented practice resulting presence 580,000 targets primarily located china attacks 320gbps
|
Internet protocols
|
truecaller truecaller smartphone application features caller-identification call-blocking flash-messaging call-recording chat voice uses internet service requires users provide standard cellular mobile number registering service developed swedish company true software scandinavia ab app available android ios blackberry symbian windows mobile windows phone truecaller developed true software scandinavia ab privately held company stockholm sweden founded alan mamedi nami zarringhalam 2009 initially launched blackberry 1 july 2009 good response users launched symbian microsoft windows mobile released android apple iphone 23 september 2009 rim blackberry 27 february 2012 windows phone 1 march 2012 nokia series 40 3 september 2012 truecaller five million users performing 120 million searches telephone number database every month 22 january 2013 truecaller reached 10 million users january 2017 truecaller reached 250 million users worldwide 18 september 2012 techcrunch announced openocean venture capital fund led former mysql nokia executives including michael widenius founder mysql investing us 1.3 million truecaller push truecaller โ global reach truecaller said intended use new funding expand footprint key markets โspecifically north america asia middle east february 2014 truecaller received 18.8 million funding sequoia capital alongside existing investor openocean truecaller chairman stefan lennhammer unnamed private investor also announced partnership yelp use yelp api data help identify business numbers call smartphone october year received 60 million niklas zennstrom atomico investment firm kleiner perkins caufield byers 7 july 2015 truecaller launched sms app called truemessenger exclusively india truemessenger enables users identify sender sms messages launch aimed increasing company user base india 17 july 2013 truecaller servers allegedly hacked syrian electronic army group claimed twitter handle recovered 459 gbs database primarily due older version wordpress installation servers 18 july 2013 truecaller issued statement blog stating website indeed hacked claiming attack disclose passwords credit card information
|
Computer security
|
apache orc apache orc optimized row columnar free open-source column-oriented data storage format apache hadoop ecosystem similar columnar-storage file formats available hadoop ecosystem rcfile parquet compatible data processing frameworks hadoop environment february 2013 optimized row columnar orc file format announced hortonworks collaboration facebook month later apache parquet format announced developed cloudera twitter apache orc comparable rcfile parquet file formats -- -all three fall category columnar data storage within hadoop ecosystem better compression encoding improved read performance cost slower writes
|
Distributed computing architecture
|
biclique attack biclique attack variant meet-in-the-middle mitm method cryptanalysis utilizes biclique structure extend number possibly attacked rounds mitm attack since biclique cryptanalysis based mitm attacks applicable block ciphers iterated hash-functions biclique attacks known broken full aes full idea though slight advantage brute force also applied kasumi cipher preimage resistance skein-512 sha-2 hash functions biclique attack still best publicly known single-key attack aes computational complexity attack formula_1 formula_2 formula_3 aes128 aes192 aes256 respectively publicly known single-key attack aes attacks full number rounds previous attacks attacked round reduced variants typically variants reduced 7 8 rounds computational complexity attack formula_1 theoretical attack means security aes broken use aes remains relatively secure biclique attack nevertheless interesting attack suggests new approach performing cryptanalysis block ciphers attack also rendered information aes brought question safety-margin number rounds used therein original mitm attack first suggested diffie hellman 1977 discussed cryptanalytic properties des argued key-size small reapplying des multiple times different keys could solution key-size however advised using double-des suggested triple-des minimum due mitm attacks mitm attacks easily applied double-des reduce security formula_5 formula_6 since one independently bruteforce first second des-encryption plain- ciphertext since diffie hellman suggested mitm attacks many variations emerged useful situations basic mitm attack inapplicable biclique attack variant first suggested dmitry khovratovich rechberger savelieva use hash-function cryptanalysis however bogdanov khovratovich rechberger showed apply concept bicliques secret-key setting including block-cipher cryptanalysis published attack aes prior mitm attacks aes many block ciphers received little attention mostly due need independent key bits two 'mitm subciphers order facilitate mitm attack โ something hard achieve many modern key schedules aes general explanation biclique structure see article bicliques mitm attack keybits formula_7 formula_8 belonging first second subcipher need independent need independent else matched intermediate values plain- ciphertext computed independently mitm attack variants mitm attacks blocks shared key-bits see 3-subset mitm attack property often hard exploit larger number rounds due diffusion attacked cipher br simply put rounds attack larger subciphers larger subciphers fewer independent key-bits subciphers bruteforce independently course actual number independent key-bits subcipher depends diffusion properties key-schedule way biclique helps tackling allows one instance attack 7 rounds aes using mitm attacks utilizing biclique structure length 3 i.e covers 3 rounds cipher map intermediate state start round 7 end last round e.g 10 aes128 thus attacking full number rounds cipher even possible attack amount rounds basic mitm attack meaning biclique thus build structure effectively map intermediate value end mitm attack ciphertext end ciphertext intermediate state gets mapped end course depends key used encryption key used map state ciphertext biclique based keybits bruteforced first second subcipher mitm attack essence biclique attacks thus besides mitm attack able build biclique structure effectively depending keybits formula_7 formula_8 map certain intermediate state corresponding ciphertext get formula_11 intermediate states formula_11 ciphertexts compute keys maps requires formula_13 key-recoveries since intermediate state needs linked ciphertexts preliminary br remember function biclique map intermediate values formula_14 ciphertext-values formula_15 based key formula_16 br formula_17 procedure br step one intermediate state formula_18 ciphertext formula_19 key formula_20 chosen formula_21 formula_22 function maps intermediate state ciphertext using given key denoted base computation step two two sets related keys size formula_11 chosen keys chosen words br input difference 0 map output difference formula_28 key difference formula_31 differences respect base computation br input difference formula_29 map output difference 0 key difference formula_33 differences respect base computation step three since trails share non-linear components s-boxes trails combined get br formula_34 br conforms definitions differentials step 2 br trivial see tuple formula_35 base computation also conforms definition differentials differentials respect base computation substituting formula_36 formula_20 two definitions yield formula_38 since formula_39 formula_40 br means tuple base computation also xor'ed combined trails formula_41 step four trivial see br formula_42 br formula_43 br formula_44 br substituted combined differential trails result br formula_45 br definition earlier biclique br formula_17 thus possible create biclique size formula_13 formula_13 since formula_11 keys first set keys combined formula_11 keys second set keys means biclique size formula_13 created using formula_52 computations differentials formula_28 formula_29 formula_22 formula_56 formula_57 keys formula_16 also different biclique way biclique constructed leading biclique attack aes practical limitations constructing bicliques technique longer biclique rounds differential trails cover diffusion properties cipher thus plays crucial role effectiveness constructing biclique bogdanov khovratovich rechberger also describe another way construct biclique called 'interleaving related-key differential trails article biclique cryptanalysis full aes step one attacker groups possible keys key-subsets size formula_13 formula_60 key group indexed formula_16 matrix size formula_62 attacker splits cipher two sub-ciphers formula_22 formula_64 formula_65 normal mitm attack set keys sub-ciphers cardinality formula_11 called formula_67 formula_68 combined key sub-ciphers expressed aforementioned matrix formula_69 step two attacker builds biclique group formula_13 keys biclique dimension-d since maps formula_11 internal states formula_72 formula_11 ciphertexts formula_74 using formula_13 keys section build biclique suggests build biclique using independent related-key differentials biclique case built using differentials set keys formula_67 formula_68 belonging sub-ciphers step three attacker takes formula_11 possible ciphertexts formula_74 asks decryption-oracle provide matching plaintexts formula_80 step four attacker chooses internal state formula_72 corresponding plaintext formula_80 performs usual mitm attack formula_22 formula_64 attacking internal state plaintext step five whenever key-candidate found matches formula_72 formula_80 key tested another plain-/ciphertext pair key validates pair highly likely correct key following example based biclique attack aes paper biclique cryptanalysis full aes br descriptions example uses terminology authors attack used i.e variable names etc br simplicity attack aes128 variant covered below. br attack consists 7-round mitm attack biclique covering last 3 rounds key-space partitioned formula_87 groups keys group consist formula_88 keys br formula_87 groups unique base-key formula_20 base-computation selected br base-key two specific bytes set zero shown table represents key way aes 4x4 matrix aes128 br remaining 14 bytes 112 bits key enumerated yields formula_87 unique base-keys one group keys br ordinary formula_88 keys group chosen respect base-key chosen nearly identical base-key vary 2 bytes either formula_94 formula_95 shown 4 bytes br gives formula_97 formula_98 combined gives formula_88 different keys formula_16 formula_88 keys constitute keys group respective base key formula_87 bicliques constructed using independent related-key differentials technique described construct biclique section br requirement using technique forward- backward-differential trails need combined share active non-linear elements known case br due way keys step 1 chosen relation base key differential trails formula_28 using keys formula_67 never share active s-boxes non-linear component aes differential trails formula_29 using key formula_68 therefore possible xor differential trails create biclique bicliques created mitm attack almost begin mitm attack formula_11 intermediate values plaintext br formula_108 br formula_11 intermediate values ciphertext br formula_110 br corresponding intermediate states sub-keys formula_67 formula_68 precomputed stored however mitm attack carried order test key formula_16 necessary recalculate parts cipher known vary formula_108 formula_115 backward computation formula_72 formula_117 4 s-boxes needs recomputed forwards computation formula_80 formula_119 3 in-depth explanation amount needed recalculation found biclique cryptanalysis full aes paper example taken intermediate values match key-candidate formula_16 formula_80 formula_72 found key-candidate tested another plain-/ciphertext pair attack lowers computational complexity aes128 formula_123 3โ5 times faster bruteforce approach data complexity attack formula_124 memory complexity formula_125
|
Computer security
|
umc green cpu umc green cpu x86-compatible microprocessor produced umc taiwanese semiconductor company early- mid-1990s offered alternative intel 80486 pin compatible enabling installed 80486 motherboards models power management features intended reduce electricity consumption umc green cpu available different features physical characteristics clock speeds sold limited quantities models feature 8 kb level 1 cache operate clock speeds 25 mhz 33 mhz 40 mhz functionally models except u5d identical differed intended application voltage rating physical packaging u5sd contain floating point unit indistinguishable u5s chips operation though unusual features 486dx pinout opposed common 486sx pinout versions would allow installation certain older motherboards may upgrade sockets hardwired fit 486dx chips one largest chip foundry owners taiwan umc owns several fabrication plants allowed fabricate designs whereas manufacturers notably cyrix contract process third parties ibm texas instruments available models green cpu produced 0.6 ฮผm cmos process chips available plastic ceramic packages different applications majority pqfp variants sold motherboard manufacturers low-cost embedded solution umc u5 series design focused microcode optimizations equivalently clocked intel amd processor required 40 cycles perform integer division whereas umc processors required 7 allowing instruction complete significantly faster performance generally observed higher competing processors clock-for-clock basis 40 mhz u5s model comparable amd am486sx2 66 mhz correctly configured motherboards due error microcode microsoft windows 98 second edition identifies processors intel pentium mmx could cause operating system software running within crash exhibit undefined behavior umc produced small quantity clock doubling processors labeled u486dx2 processors designed compete clock doubling solutions intel 80486dx2 amd am486dx2 cyrix cx486dx2 due ongoing legal troubles umc withdrew u486dx2 production processor ever produced engineering sample never made market manufactured 0.35 ฮผm cmos process contained within ceramic package 1994 intel alleged umc infringed upon patent 80486 microprocessor filed complaints umc distributors umc countered claims anti-trust suit case eventually settled court umc withdrawing product ceasing production 80486-compatible microprocessors result dispute processors prohibited sale within united states visibly labeled placement label varies ceramic u5s u5d models typically display u.s. sale import part silkscreen top chip u5sx u5sd models usually u.s. sale printed onto golden die cover underside package labeling often absent plastic packages
|
Computer architecture
|
power virus power virus computer program executes specific machine code reach maximum cpu power dissipation thermal energy output central processing units computer cooling apparatus designed dissipate power thermal design power rather maximum power power virus could cause system overheat logic stop processor may cause permanent physical damage power viruses malicious often suites test software used integration testing thermal testing computer components design phase product product benchmarking stability test applications similar programs effect power viruses high cpu usage stay user control used testing cpus example overclocking spinlock poorly written program may cause similar symptoms lasts sufficiently long different micro-architectures typically require different machine code hit maximum power examples machine code appear distributed cpu reference materials
|
Computer security
|
confederation european data protection organisations confederation european data protection organisations cedpo european umbrella organisation data protection organisations cedpo founded september 2011 national data protection organisations european umbrella organisation far 2014 without explicit legal form cedpo pursues promote role data protection officer provide advice balanced practicable effective data protection addition cedpo aims contribute better harmonisation data protection law practices european union eu european economic area eea four founder members cedpo association franรงaise des correspondants ร la protection des donnรฉes ร caractรจre personnel afcdp france asociaciรณn profesional espaรฑola de privacidad apep spain gesellschaft fรผr datenschutz und datensicherheit e.v gdd germany nederlands genootschap van functionarissen voor de gegevensbescherming ngfg netherlands present legal entities cedpo include
|
Computer security
|
superbasic superbasic advanced variant basic programming language many structured programming additions developed sinclair research jan jones early 1980s originally superbasic intended home computer code-named superspectrum development project later cancelled however superbasic subsequently included rom firmware sinclair ql microcomputer announced january 1984 also serving command line interpreter ql qdos operating system notable first second-generation basic integrated microcomputer operating system making latter user-extendableโas exemplified linus torvalds formative years example illustrates last eight features entering statements entering print fri screen cleared e.g entering new function iso act like extension operating system similarly according ql user guide many operating system commands defined procedures auto 11,2
|
Programming language topics
|
rsocket rsocket application protocol initially developed netflix supports reactive streams motivation behind development replace hypertext transfer protocol http inefficient many tasks microservices communication protocol less overhead rsocket binary protocol use byte stream transports tcp websockets aeron enables following symmetric interaction models via async message passing single connection supports session resumption allow resuming long-lived streams across different transport connections particularly useful mobileโนโโบserver communication network connections drop switch reconnect frequently
|
Internet protocols
|
kenneth e. iverson kenneth eugene iverson 17 december 1920 โ 19 october 2004 canadian computer scientist noted development programming language apl honored turing award 1979 pioneering effort programming languages mathematical notation resulting computing field knows apl contributions implementation interactive systems educational uses apl programming language theory practice ken iverson born 17 december 1920 near camrose town central alberta canada parents farmers came alberta north dakota ancestors came trondheim norway world war ii served first canadian army royal canadian air force received b.a degree queen university m.sc ph.d. degrees harvard university career worked harvard ibm i. p. sharp associates jsoftware inc. nรฉe iverson software inc. iverson suffered stroke working computer new j lab 16 october 2004 died 19 october 2004 age 83 iverson began school 1 april 1926 one-room school initially grade 1 promoted grade 2 3 months grade 4 end june 1927 left school grade 9 depths great depression work family farm thought schooling led becoming schoolteacher desire become one age 17 still school enrolled correspondence course radios de forest training chicago learned calculus self-study textbook world war ii serving royal canadian air force took correspondence courses toward high school diploma war iverson enrolled queen university kingston ontario taking advantage government support ex-servicemen threat air force buddy said would beat brains grasp opportunity graduated 1950 top student bachelor degree mathematics physics continuing education harvard university began department mathematics received master degree 1951 switched department engineering applied physics working howard aiken wassily leontief howard aiken developed harvard mark one first large-scale digital computers wassily leontief economist developing inputโoutput model economic analysis work would later receive nobel prize leontief model required large matrices iverson worked programs could evaluate matrices harvard mark iv computer iverson received ph.d. applied mathematics 1954 dissertation based work harvard iverson met eoin whitney 2-time putnam fellow fellow graduate student alberta future ramifications iverson stayed harvard assistant professor implement world first graduate program automatic data processing period iverson developed notation describing analyzing various topics data processing teaching classes writing brooks automatic data processing appalled find conventional mathematical notation failed fill needs began work extensions notation suitable particular adopted matrix algebra used thesis work systematic use matrices higher-dimensional arrays tensor analysis operators sense heaviside treatment maxwell equations higher-order functions function argument function result notation also field-tested business world 1957 6-month sabbatical spent mckinsey company first published paper using notation description finite sequential processes initially report number 23 bell labs later revised presented fourth london symposium information theory august 1960 iverson stayed harvard five years failed get tenure n't published anything one little book iverson joined ibm research 1960 doubled salary preceded ibm fred brooks advised stick whatever really wanted management starved ideas anything clearly crazy would find support particular allowed finish publish programming language brooks automatic data processing two books described used notation developed harvard automatic data processing programming language began one book material grew magnitude level separation proved wise ibm iverson soon met adin falkoff worked together next twenty years chapter 2 programming language used iverson notation describe ibm 7090 computer early 1963 falkoff later joined iverson ed sussenguth proceeded use notation produce formal description ibm system/360 computer design result published 1964 double issue ibm systems journal thereafter known grey book grey manual book used course computer systems design ibm systems research institute consequence formal description attracted interest bright young minds one hotbed interest stanford university included larry breed phil abrams roger moore charles brenner mike jenkins later made contributions apl donald mcintyre head geology pomona college first general customer installation 360 system used formal description become expert ibm systems engineer assigned pomona completion formal description falkoff iverson turned attention implementation work brought rapid fruition 1965 larry breed phil abrams joined project produced fortran-based implementation 7090 called ivsys iverson system autumn 1965 first batch mode later early 1966 time-shared interactive mode subsequently breed dick lathwell ex university alberta roger moore i. p. sharp associates produced system/360 implementation three received grace murray hopper award 1973 work design implementation apl\360 setting new standards simplicity efficiency reliability response time interactive systems 360 implementation work underway iverson notation renamed apl falkoff workspace 1 cleanspace saved 1966-11-27 22.53.58 utc apl\360 service began within ibm several weeks outside ibm 1968 additional information implementation apl\360 found acknowledgements apl\360 user manual appendix chronology apl development design apl formal description especially implementation drove evolution language process consolidation regularization typography linearization syntax function definition described apl\360 history design apl evolution apl two treatises period conventions governing order evaluation algebra language apologias apl notation notation used falkoff iverson teach various topics various universities ibm systems research institute 1964 iverson used notation one-semester course seniors fox lane high school later swarthmore high school apl became available first application teach formal methods systems design nasa goddard also used hotchkiss school lower canada college scotch plains high school atlanta public schools among others one school students became eager broke school hours get apl computer time another apl enthusiasts steered newbies basic maximize apl time 1969 iverson apl group inaugurated ibm philadelphia scientific center 1970 named ibm fellow used funding came ibm fellow bring visiting teachers professors various fields including donald mcintyre pomona jeff shallit summer student period several months visitors would start using apl expositions fields hope later would continue use apl home institutions iverson work time centered several disciplines including collaborative projects circuit theory genetics geology calculus psc closed 1974 group transferred california others including iverson remained east later transferring back ibm research iverson received turing award 1979 following table lists publications iverson authored co-authored ibm reflect two main strands work 1980 iverson left ibm i. p. sharp associates apl time-sharing company preceded ibm colleagues paul berry joey tuttle dick lathwell eugene mcdonnell ipsa apl language systems group managed eric iverson ken iverson son roger moore one apl\360 implementers vice president iverson worked develop extend apl lines presented operators functions language work gained impetus 1981 arthur whitney iverson produced model apl written apl time working ipsa oag database iverson introduced arthur whitney son eoin whitney apl 11-years-old 1974 recommended summer student position ipsa calgary model apl syntax driven 11-by-5 table whitney also invented rank operator process language design simplified extended rationalized apl january 1983 multiple editions dictionary apl language 1984 1987 dictionary apl september 1987 within ipsa phrase dictionary apl came use denote apl specified dictionary apl referred dictionary dictionary apl syntax controlled 9-by-6 table parsing process precisely succinctly described table 2 primitive monadic โฅ modeled apl word formation lexing 1970s 1980s main apl vendors ibm stsc ipsa three active developing extending language ibm apl2 based work jim brown work apl2 proceeded intermittently 15 years actual coding starting 1971 apl2 becoming available iup installed user program ibm product classification 1982 stsc experimental apl system called nars designed implemented bob smith nars apl2 differed fundamental respects dictionary apl differed i.p sharp implemented new apl ideas stages complex numbers enclosed boxed arrays match composition operators 1981 determinant operator 1982 rank operator link left right identity functions 1983 however domains operators still restricted primitive functions subsets thereof 1986 ipsa developed sax sharp apl/unix written c based implementation stsc language specified dictionary restrictions domains operators alpha version sax became available within i.p sharp around december 1986 early 1987 education iverson developed sharp apl minicourse used teach ipsa clients use apl applied mathematics programmers mathematics programming used computer science courses t.h twente publications iverson authored co-authored i. p. sharp associates iverson retired i. p. sharp associates 1987 kept busy jobs regarding language design significant activities period invention fork 1988 years struggled find way write f+g calculus scalar operators 1978 til operator 1982 catenation reshape operators 1984 union intersection operators 1987 yoke 1988 finally forks 1988 forks defined follows moreover f g p q r โโ f g p q r thus write f+g calculus one write f+g apl iverson eugene mcdonnell worked details long plane rides apl88 conference sydney australia iverson coming initial idea waking nap iverson presented rationale work post 1987 follows roger hui described final impetus got j started appendix implementation j hui classmate whitney university alberta studied dictionary apl language jobs modelled parsing process least two different ways investigated uses dictionary apl diverse applications well january 1987 august 1989 access sax later part period used daily basis j initially took dictionary apl specification j interpreter built around table 2 dictionary c data program structures designed parse table c corresponded directly parse table dictionary retrospect iverson apl87 paper apl87 five pages prescribed essential steps writing apl interpreter particular sections word formation parsing arthur whitney addition one-page thing contributed j development suggesting primitives oriented leading axis agreement generalization scalar extension prefix instead suffix total array ordering defined one objectives implement fork turned rather straightforward inclusion one additional row parse table choice implement forks fortuitous fortunate realized later forks made tacit expressions operator expressions complete following sense sentence involving one two arguments use arguments operand written tacitly fork compose left right identity functions constant functions two obvious differences j apl dialects use terms natural languages instead mathematics computer science practice began dictionary apl noun verb adverbs alphabet word formation sentence ... instead array function operator character set lexing expression ... b use 7-bit ascii characters instead special symbols differences j apl described j apl programmer apl j j source code available jsoftware gnu general public license version 3 gpl3 commercial alternative eric iverson founded iverson software inc. february 1990 provide improved sharp apl/pc product quickly became obvious shared interests goals may 1990 iverson hui joined iverson software inc. later joined chris burke company soon became j name changed jsoftware inc. april 2000 publications iverson authored co-authored iverson software inc. jsoftware inc.
|
Programming language topics
|
explicitly parallel instruction computing explicitly parallel instruction computing epic term coined 1997 hpโintel alliance describe computing paradigm researchers investigating since early 1980s paradigm also called independence architectures basis intel hp development intel itanium architecture hp later asserted epic merely old term itanium architecture epic permits microprocessors execute software instructions parallel using compiler rather complex on-die circuitry control parallel instruction execution intended allow simple performance scaling without resorting higher clock frequencies 1989 researchers hp recognized reduced instruction set computer risc architectures reaching limit one instruction per cycle began investigation new architecture later named epic basis research vliw multiple operations encoded every instruction processed multiple execution units one goal epic move complexity instruction scheduling cpu hardware software compiler instruction scheduling statically help trace feedback information eliminates need complex scheduling circuitry cpu frees space power functions including additional execution resources equally important goal exploit instruction level parallelism ilp using compiler find exploit additional opportunities parallel execution vliw least original forms several short-comings precluded becoming mainstream epic architecture evolved vliw architecture retained many concepts superscalar architecture epic architectures add several features get around deficiencies vliw epic architecture also includes grab-bag architectural concepts increase ilp itanium architecture also added rotating register files tool useful software pipelining since avoids manually unroll rename registers investigations epic architectures directly tied development itanium architecture
|
Computer architecture
|
guido van rossum guido van rossum born 31 january 1956 dutch programmer best known author python programming language benevolent dictator life bdfl stepped position july 2018 currently member python steering council van rossum born raised netherlands received master degree mathematics computer science university amsterdam 1982 brother van rossum type designer programmer designed typeface used python powered logo guido lives belmont california wife kim knapp son according home page dutch naming conventions van name capitalized referred surname alone using first last name together working centrum wiskunde informatica cwi van rossum wrote contributed glob routine bsd unix 1986 helped develop abc programming language stated try mention abc influence 'm indebted everything learned project people worked also created grail early web browser written python engaged discussions html standard worked various research institutes including centrum wiskunde informatica cwi netherlands u.s. national institute standards technology nist corporation national research initiatives cnri 2000 2003 worked zope corporation 2003 van rossum left zope elemental security worked custom programming language organization 2005 december 2012 worked google spent half time developing python language january 2013 started working dropbox december 1989 van rossum looking hobby programming project would keep occupied week around christmas office closed decided write interpreter new scripting language thinking lately descendant abc would appeal unix/c hackers attributes choosing name python slightly irreverent mood big fan monty python flying circus explained python predecessor abc inspired setl noting abc co-developer lambert meertens spent year setl group nyu coming final abc design july 2018 van rossum announced would stepping position bdfl python programming language 1999 van rossum submitted funding proposal darpa called computer programming everybody defined goals python python grown become popular programming language 2018 third popular language github social coding website behind javascript java according programming language popularity survey consistently amongst top 10 mentioned languages job postings furthermore python consistently top 10 popular languages according tiobe programming community index google van rossum developed mondrian web-based code review system written python used within company named software dutch painter piet mondrian named another related software project gerrit rietveld dutch designer 2013 van rossum started working cloud file storage company dropbox
|
Programming language topics
|
richard menta richard menta american journalist publisher mp3 newswire known decade commentary followed evolution digital media intellectual property protection menta also information security professional 1990s menta worked various publishers including simon schuster american lawyer media built business models designed leverage offline content online world included early experimentation digital audio video oversaw eventually led found mp3 newswire 1999 menta steered mp3 newswire original content making place knowledgeable professionals share opinions
|
Computer security
|
architecture description language architecture description languages adls used several disciplines system engineering software engineering enterprise modelling engineering system engineering community uses architecture description language language and/or conceptual model describe represent system architectures software engineering community uses architecture description language computer language create description software architecture case so-called technical architecture architecture must communicated software developers functional architecture communicated various stakeholders users adls developed acme developed cmu aadl standardized sae c2 developed uci sbc-adl developed national sun yat-sen university darwin developed imperial college london wright developed cmu iso/iec/ieee 42010 document systems software engineeringโarchitecture description defines architecture description language form expression use architecture descriptions specifies minimum requirements adls enterprise modelling engineering community also developed architecture description languages catered enterprise level examples include archimate standard open group demo abacus developed university technology sydney languages necessarily refer software components etc however refer application architecture architecture communicated software engineers writing refers primarily perspective software engineering community standard notation adl representing architectures helps promote mutual communication embodiment early design decisions creation transferable abstraction system architectures past largely represented box-and-line drawing annotated things nature component properties semantics connections overall system behavior adls result linguistic approach formal representation architectures address shortcomings also important sophisticated adls allow early analysis feasibility testing architectural design decisions adls classified three broad categories box-and-line informal drawings formal architecture description language uml unified modeling language -based notations box-and-line long time predominant means describing sas providing useful documentation level informality limited usefulness architecture description rigorous way describing sas required quoting allen garlan 1997 box-and-line descriptions may provide useful documentation current level informality limits usefulness since generally imprecise meant architectural descriptions may impossible analyze architecture consistency determine non-trivial properties moreover way check system implementation faithful architectural design similar conclusion drawn perry wolf 1992 reports aside providing clear precise documentation primary purpose specifications provide automated analysis documents expose various kinds problems would otherwise go undetected since thread research formal languages sa description carried tens formal adls proposed characterized different conceptual architectural elements different syntax semantics focusing specific operational domain suitable different analysis techniques example domain-specific adls presented deal embedded real-time systems aadl east-adl eadl control-loop applications diaspec product line architectures koala dynamic systems ฯ-adl analysis-specific adls proposed deal availability reliability security resource consumption data quality real-time performance analysis aadl behavioral analysis fractal trustworthiness analysis tadl however efforts seen desired adoption industrial practice reasons lack industry adoption analyzed woods hilliard pandey clements others formal adls rarely integrated software life-cycle seldom supported mature tools scarcely documented focusing specific needs leaving space extensions enabling addition new features way overcome limitations uml indicated possible successor existing adls many proposals presented use extend uml properly model software architectures fact highlighted recent study conducted practitioners whilst practitioners generally satisfied design capabilities provided languages use dissatisfied architectural language analysis features abilities define extra-functional properties architectural languages used practice mostly originate industrial development instead academic research formality better usability required architectural language large variety adls developed either academic industrial groups many languages intended adl turn suitable representing analyzing architecture principle adls differ requirements languages adls rooted solution space whereas requirements describe problem spaces differ programming languages adls bind architectural abstractions specific point solutions modeling languages represent behaviors adls focus representation components however domain specific modeling languages dsmls focus representation components minimal requirements language must adls common adls differ ability adl community generally agrees software architecture set components connections among different kind architectures like adls implement interface connection architecture architecture context software systems roughly divided categories primarily software architecture network architecture systems architecture within categories tangible fuzzy distinction architecture design draw distinction universally clearly possible best consider design noun rather verb comparison two nouns design abstraction specification patterns organs functionality implemented architecture degree higher abstraction granularity consequentially architecture also topological nature design specifies major components meet relate one another architecture focuses partitioning major regions functionality high level components physically virtually reside off-the-shelf components may employed effectively general interfaces component expose protocols employed practices high level patterns may best meet extensibility maintainability reliability durability scalability non-functional objectives design detailing choices concrete clarification functional requirements met delegation pieces functionality granular components smaller components organized within larger ones oftentimes portion architecture done conceptualization application system network may appear non-functional sections requirement documentation canonically design specified requirements rather driven process defining architecture may involve heuristics acquired architect architectural team experience within domain design architecture often evolves series iterations wisdom high level design often tested low level design implementation occurs wisdom architecture tested specification high level design cases wisdom specification called question detailing another iteration either architecture design case may may become necessary summary primary differences architecture design ones granularity abstraction consequentially chronology architecture generally precedes design although overlap circular iteration common reality list gives candidates best adl date up-to-date list currently existing architectural languages please refer up-to-date list adls approaches architecture
|
Programming language topics
|
access token computer systems access token contains security credentials login session identifies user user groups user privileges cases particular application typically one may asked enter access token example 40 character long gibberish rather usual password therefore kept secret like password access token object encapsulating security identity process thread token used make security decisions store tamper-proof information system entity token generally used represent security information capable holding additional free-form data attached token created tokens duplicated without special privilege example create new token lower levels access rights restrict access launched application access token used windows process thread tries interact objects security descriptors securable objects windows access token represented system object type codice_1 access token generated logon service user logs system credentials provided user authenticated authentication database authentication database contains credential information required construct initial token logon session including user id primary group id groups part information token attached initial process created user session inherited subsequent processes created initial process whenever process opens handle resource access control enabled windows reconciles data target object security descriptor contents current effective access token result access check evaluation indication whether access allowed operations read write/modify etc calling application allowed perform two types tokens available token composed various fields including
|
Operating systems
|
list sony ericsson products following list products manufactured sony ericsson brand models released multiple names depending region release currently usually indicated letter added end model number international north america c mainland china indicated mostly older models slightly differing model number typically one version european us market another asian market however models yet versions walkman branded models also released non-walkman version sony ericsson w580 s500 versions usually differ slightly phones boldface indicates phone smartphone status p indicates production discontinued u indicates upcoming sony ericsson c902 released second quarter 2008 java based feature device running sony ericsson proprietary a200 platform special feature presence 8 touch sensitive keys using capacitive technology camera mode camera technology includes face detection music player similar system used company walkman series handsets phone first sony ericsson new 'cyber-shot c-series phones designed successor popular k800i k850 c902 featured james bond film quantum solace praised user interface design build quality although device received favourable reviews analysts expect reach level popularity sales predecessor k800i intended flagship model sony ericsson g700 announced mobile world congress formerly 3gsm congress february 2008 based symbian os 9.1 uiq 3.0 platform handset average reviews lot reviewers criticizing phone priced high better equipped g900 price bracket others lamented fact sony ericsson chose implement technology presented late 2006 p1 business edition also exists sony ericsson g700 camera announced 2008 mobile world congress formerly 3gsm congress february year g900 mid-to-high-end smartphone based symbian 9.1 uiq 3.0 platform phone sports high quality sound 3g wi-fi clear 5.0-megapixel camera phones cyber-shot branding first entertainment unlimited phones announced launched 2009 creating new category benefits audio images combined smart good-looking high-performing devices apart first-rate audio-visual strength products common differentiating factors user interface borrowing wider sony group ui-developments aino first product connects world sony playstation remotely via remote media play vivaz first sony ericsson phone supporting high definition hd video capture note lists intended inclusive information may missing date note lists incomplete information may missing sun visor handsfree bluetooth hch- xx phone holder following speaker drain power fastport batteries wall socked needed newer products without fastport fastport models trrs 4-pole 3.5 mm jack omtp models
|
Operating systems
|
multi-core processor multi-core processor computer processor integrated circuit two separate processing units called cores reads executes program instructions computer several processors instructions ordinary cpu instructions add move data branch single processor run instructions separate cores time increasing overall speed programs support multithreading parallel computing techniques manufacturers typically integrate cores onto single integrated circuit die known chip multiprocessor cmp onto multiple dies single chip package microprocessors currently used almost personal computers multi-core multi-core processor implements multiprocessing single physical package designers may couple cores multi-core device tightly loosely example cores may may share caches may implement message passing shared-memory inter-core communication methods common network topologies interconnect cores include bus ring two-dimensional mesh crossbar homogeneous multi-core systems include identical cores heterogeneous multi-core systems cores identical e.g big.little heterogeneous cores share instruction set amd accelerated processing units cores n't even share instruction set single-processor systems cores multi-core systems may implement architectures vliw superscalar vector multithreading multi-core processors widely used across many application domains including general-purpose embedded network digital signal processing dsp graphics gpu improvement performance gained use multi-core processor depends much software algorithms used implementation particular possible gains limited fraction software run parallel simultaneously multiple cores effect described amdahl law best case so-called embarrassingly parallel problems may realize speedup factors near number cores even problem split enough fit within core cache avoiding use much slower main-system memory applications however accelerated much unless programmers invest prohibitive amount effort re-factoring whole problem parallelization software significant ongoing topic research terms multi-core dual-core commonly refer sort central processing unit cpu sometimes also applied digital signal processors dsp system chip soc terms generally used refer multi-core microprocessors manufactured integrated circuit die separate microprocessor dies package generally referred another name multi-chip module article uses terms multi-core dual-core cpus manufactured integrated circuit unless otherwise noted contrast multi-core systems term multi-cpu refers multiple physically separate processing-units often contain special circuitry facilitate communication terms many-core massively multi-core sometimes used describe multi-core architectures especially high number cores tens thousands systems use many soft microprocessor cores placed single fpga core considered semiconductor intellectual property core well cpu core manufacturing technology improves reducing size individual gates physical limits semiconductor-based microelectronics become major design concern physical limitations cause significant heat dissipation data synchronization problems various methods used improve cpu performance instruction-level parallelism ilp methods superscalar pipelining suitable many applications inefficient others contain difficult-to-predict code many applications better suited thread-level parallelism tlp methods multiple independent cpus commonly used increase system overall tlp combination increased available space due refined manufacturing processes demand increased tlp led development multi-core cpus several business motives drive development multi-core architectures decades possible improve performance cpu shrinking area integrated circuit ic reduced cost per device ic alternatively circuit area transistors could used design increased functionality especially complex instruction set computing cisc architectures clock rates also increased orders magnitude decades late 20th century several megahertz 1980s several gigahertz early 2000s rate clock speed improvements slowed increased use parallel computing form multi-core processors pursued improve overall processing performance multiple cores used cpu chip could lead better sales cpu chips two cores example intel produced 48-core processor research cloud computing core x86 architecture since computer manufacturers long implemented symmetric multiprocessing smp designs using discrete cpus issues regarding implementing multi-core processor architecture supporting software well known additionally order continue delivering regular performance improvements general-purpose processors manufacturers intel amd turned multi-core designs sacrificing lower manufacturing-costs higher performance applications systems multi-core architectures developed alternatives especially strong contender established markets integration peripheral functions chip proximity multiple cpu cores die allows cache coherency circuitry operate much higher clock rate possible signals travel off-chip combining equivalent cpus single die significantly improves performance cache snoop alternative bus snooping operations put simply means signals different cpus travel shorter distances therefore signals degrade less higher-quality signals allow data sent given time period since individual signals shorter need repeated often assuming die physically fit package multi-core cpu designs require much less printed circuit board pcb space multi-chip smp designs also dual-core processor uses slightly less power two coupled single-core processors principally decreased power required drive signals external chip furthermore cores share circuitry like l2 cache interface front-side bus fsb terms competing technologies available silicon die area multi-core design make use proven cpu core library designs produce product lower risk design error devising new wider-core design also adding cache suffers diminishing returns multi-core chips also allow higher performance lower energy big factor mobile devices operate batteries since core multi-core cpu generally energy-efficient chip becomes efficient single large monolithic core allows higher performance less energy challenge however additional overhead writing parallel code maximizing usage computing resources provided multi-core processors requires adjustments operating system os support existing application software also ability multi-core processors increase application performance depends use multiple threads within applications integration multi-core chip lower chip production yields also difficult manage thermally lower-density single-core designs intel partially countered first problem creating quad-core designs combining two dual-core ones single die unified cache hence two working dual-core dies used opposed producing four cores single die requiring four work produce quad-core cpu architectural point view ultimately single cpu designs may make better use silicon surface area multiprocessing cores development commitment architecture may carry risk obsolescence finally raw processing power constraint system performance two processing cores sharing system bus memory bandwidth limits real-world performance advantage 2009 report dr jun ni showed single core close memory-bandwidth limited going dual-core might give 30 70 improvement memory bandwidth problem 90 improvement expected however amdahl law makes claim dubious would possible application used two cpus end running faster single-core one communication cpus limiting factor would count 100 improvement trend processor development towards ever-increasing number cores processors hundreds even thousands cores become theoretically possible addition multi-core chips mixed simultaneous multithreading memory-on-chip special-purpose heterogeneous asymmetric cores promise performance efficiency gains especially processing multimedia recognition networking applications example big.little core includes high-performance core called 'big low-power core called 'little also trend towards improving energy-efficiency focusing performance-per-watt advanced fine-grain ultra fine-grain power management dynamic voltage frequency scaling i.e laptop computers portable media players chips designed outset large number cores rather evolved single core designs sometimes referred manycore designs emphasising qualitative differences composition balance cores multi-core architecture show great variety architectures use one core design repeated consistently homogeneous others use mixture different cores optimized different heterogeneous role article cpu designers debate multi-core future rick merritt ee times 2008 includes comments outdated version anti-virus application may create new thread scan process gui thread waits commands user e.g cancel scan cases multi-core architecture little benefit application due single thread heavy lifting inability balance work evenly across multiple cores programming truly multithreaded code often requires complex co-ordination threads easily introduce subtle difficult-to-find bugs due interweaving processing data shared threads see thread-safety consequently code much difficult debug single-threaded code breaks perceived lack motivation writing consumer-level threaded applications relative rarity consumer-level demand maximum use computer hardware although threaded applications incur little additional performance penalty single-processor machines extra overhead development difficult justify due preponderance single-processor machines also serial tasks like decoding entropy encoding algorithms used video codecs impossible parallelize result generated used help create next result entropy decoding algorithm given increasing emphasis multi-core chip design stemming grave thermal power consumption problems posed significant increase processor clock speeds extent software multithreaded take advantage new chips likely single greatest constraint computer performance future developers unable design software fully exploit resources provided multiple cores ultimately reach insurmountable performance ceiling telecommunications market one first needed new design parallel datapath packet processing quick adoption multiple-core processors datapath control plane mpus going replace traditional network processors based proprietary microcode picocode parallel programming techniques benefit multiple cores directly existing parallel programming models cilk plus openmp openhmpp fastflow skandium mpi erlang used multi-core platforms intel introduced new abstraction c++ parallelism called tbb research efforts include codeplay sieve system cray chapel sun fortress ibm x10 multi-core processing also affected ability modern computational software development developers programming newer languages might find modern languages support multi-core functionality requires use numerical libraries access code written languages like c fortran perform math computations faster newer languages like c intel mkl amd acml written native languages take advantage multi-core processing balancing application workload across processors problematic especially different performance characteristics different conceptual models deal problem example using coordination language program building blocks programming libraries higher-order functions block different native implementation processor type users simply program using abstractions intelligent compiler chooses best implementation based context managing concurrency acquires central role developing parallel applications basic steps designing parallel applications hand server side multi-core processors ideal allow many users connect site simultaneously independent threads execution allows web servers application servers much better throughput vendors may license software per processor give rise ambiguity processor may consist either single core combination cores embedded computing operates area processor technology distinct mainstream pcs technological drives towards multi-core apply indeed many cases application natural fit multi-core technologies task easily partitioned different processors addition embedded software typically developed specific hardware release making issues software portability legacy code supporting independent developers less critical case pc enterprise computing result easier developers adopt new technologies result greater variety multi-core processing architectures suppliers multi-core network processors become mainstream companies freescale semiconductor cavium networks wintegra broadcom manufacturing products eight processors system developer key challenge exploit cores devices achieve maximum networking performance system level despite performance limitations inherent symmetric multiprocessing smp operating system companies 6wind provide portable packet processing software designed networking data plane runs fast path environment outside operating system network device digital signal processing trend applies texas instruments three-core tms320c6488 four-core tms320c5441 freescale four-core msc8144 six-core msc8156 stated working eight-core successors newer entries include storm-1 family stream processors inc 40 80 general purpose alus per chip programmable c simd engine picochip three-hundred processors single die focused communication applications heterogeneous computing system uses one kind processor cores multi-core solutions becoming common xilinx zynq ultrascale+ mpsoc quad-core arm cortex-a53 dual-core arm cortex-r5 software solutions openamp used help inter processor communication mobile devices may use arm big.little architecture research development multicore processors often compares many options benchmarks developed help evaluations existing benchmarks include splash-2 parsec cosmic heterogeneous systems
|
Computer architecture
|
myarc disk operating system mdos short myarc disk operating system operating system commercialized myarc designed implemented specifically geneve 9640 paul charlton mdos designed fully emulate ti-99/4a computer providing advanced time virtual memory operating environment full support mouse gui complex mathematical applications mdos written specifically tms9995 16-bit cpu yamaha v9938 video display processor
|
Operating systems
|
ticket security security ticket number generated network server client delivered different server means authentication proof authorization easily forged usage word originated mit kerberos protocol 1980s tickets may either transparent meaning recognized without contacting server generated opaque meaning original server must contacted verify issued ticket magic cookies provide functionality ticket
|
Computer security
|
ibm 4765 ibm 4765 pcie cryptographic coprocessor hardware security module hsm includes secure cryptoprocessor implemented high-security tamper resistant programmable pcie board specialized cryptographic electronics microprocessor memory random number generator housed within tamper-responding environment provide highly secure subsystem data processing cryptography performed ibm 4765 validated fips pub 140-2 level 4 highest level certification achievable commercial cryptographic devices ibm 4765 data sheet describes coprocessor detail ibm supplies two cryptographic-system implementations toolkits custom application development also available applications may include financial pin transactions bank-to-clearing-house transactions emv transactions integrated circuit chip based credit cards general-purpose cryptographic applications using symmetric key algorithms hashing algorithms public key algorithms operational keys symmetric rsa private generated coprocessor saved either keystore file application memory encrypted master key coprocessor coprocessor identical master key use keys ibm supports 4765 ibm z ibm power systems ibm-approved x86 servers linux microsoft windows may 2011 ibm 4765 superseded ibm 4764 discontinued ibm 4765 discontinued platforms successor 4765 ibm 4767 introduced ibm server platforms links point various relevant cryptographic standards iso 13491 secure cryptographic devices https //www.iso.org/standard/61137.html iso 9564 pin security https //www.iso.org/standard/68669.html ansi x9.24 part 1 key management using symmetric techniques https //webstore.ansi.org/recorddetail.aspx sku=ansi+x9.24-1-2017 ansi x9.24 part 2 key management using asymmetric techniques https //webstore.ansi.org/recorddetail.aspx sku=ansi+x9.24-2-2016 fips 140-2 https //nvlpubs.nist.gov/nistpubs/fips/nist.fips.140-2.pdf
|
Computer security
|
indiana jones last crusade action game indiana jones last crusade action game published 1989 lucasfilm games based film name game released zx spectrum amstrad cpc commodore 64 atari st amiga ibm pc msx master system nes game boy sega genesis game gear different game also released 1989 also different game nintendo entertainment system titled indiana jones last crusade released taito 1991 movie player quest find holy grail en route player must find cross coronado knight first crusade shield indiana father grail diary computer gaming world gave game negative review said another search recover game little indiana jones review praised graphics sound found fight sequences easy short since enemies could defeated one hit turned backs shortly attacking player compute liked commodore 64 version approving graphics describing gameplay quite addicting criticizing lack savegame replay value zx spectrum sales charts reached number two behind robocop number one every month year nintendo power reviewing nes version praised action gameplay noted music levels helped recreate feel movie nintendo power impressed character graphics stated animation quite good nes nintendo power praised game boy version graphics password system challenging gameplay criticized poor hit detection time limits level made game difficult action game features six levels password feature game players rated nes version 52 percent
|
Computer architecture
|
bliss bliss system programming language developed carnegie mellon university w. a. wulf d. b. russell a. n. habermann around 1970 perhaps best known systems programming language right c made debut years later since c took bliss faded obscurity c infancy projects within bell labs debating merits bliss vs. c. bliss typeless block-structured language based expressions rather statements includes constructs exception handling coroutines macros include goto statement name variously said short basic language implementation system software system software implementation language backwards sometimes called bill language implementing system software bill wulf original carnegie mellon compiler notable extensive use optimizations formed basis classic book design optimizing compiler dec developed maintained bliss compilers pdp-10 pdp-11 vax dec prism mips dec alpha intel ia-32 language become popular among customers compiler dec used heavily in-house 1980s utility programs vms operating system written bliss-32 acquisition dec compaq developed maintained bliss compiler intel ia-64 bliss language following characteristics following example taken verbatim bliss language manual
|
Programming language topics
|
amazon relational database service amazon relational database service amazon rds distributed relational database service amazon web services aws web service running cloud designed simplify setup operation scaling relational database use applications administration processes like patching database software backing databases enabling point-in-time recovery managed automatically scaling storage compute resources performed single api call aws offer ssh connection rds instances amazon rds first released 22 october 2009 supporting mysql databases followed support oracle database june 2011 november 2014 aws announced amazon aurora mysql-compatible database offering enhanced high availability performance october 2017 postgresql-compatible database offering launched.. march 2019 aws announced support postgresql 11 rds five months official release new database instances launched aws management console using amazon rds apis amazon rds offers different features support different use cases major features may 2010 amazon announced multi-availability zone deployment support amazon rds multi-availability zone az allows users automatically provision maintain synchronous physical logical โ standby โ replica depending database engine different availability zone independent infrastructure physically separate location multi-az database instance developed creation time modified run multi-az deployment later multi-az deployments aim provide enhanced availability data durability mysql mariadb oracle postgresql sql server instances targeted production environments event planned database maintenance unplanned service disruption amazon rds automatically fails up-to-date standby allowing database operations resume without administrative intervention multi-az rds instances optional cost associated creating rds instance user asked would like use multi-az rds instance multi-az rds deployments backups done standby instance i/o activity suspended time may experience elevated latencies minutes backups read replicas allow different uses case scale read-heavy database workloads available five replicas mysql mariadb postgresql instances use native asynchronous replication functionality respective database engines backups configured default accessible used read scaling mysql mariadb read replicas made writeable since october 2012 postgresql read replicas support replicas done database server level support replication database instance table level performance metrics amazon rds available aws management console amazon cloudwatch api december 2015 amazon announced optional enhanced monitoring feature provides expanded set metrics mysql mariadb aurora database engines amazon rds instances priced similarly amazon elastic compute cloud ec2 rds charged per hour comes two packages on-demand db instances reserved db instances on-demand instances ongoing hourly usage rate reserved db instances require up-front one-time fee turn provide discount hourly usage charge instance apart hourly cost running rds instance users charged amount storage provisioned data transfers input output operations performed aws introduced provisioned input output operations user define many io per second required application iops contribute significantly total cost running rds instance part aws free tier amazon rds free tier helps new aws customers get started managed database service cloud free use amazon rds free tier develop new applications test existing applications simply gain hands-on experience amazon rds amazon rds creates saves automated backups rds db instances first snapshot db instance contains data full db instance subsequent snapshots incremental maximum retention period 35 days multi-az rds deployments backups done standby instance i/o activity suspended amount time may experience elevated latencies minutes backups database instances managed aws management console using amazon rds apis using aws cli since 1 june 2017 stop aws rds instances aws management console aws cli 7 days time 7 days automatically started since september 2018 rds instances protected accidental deletion increase db space supported decrease allocated space additionally least six-hour period new allocation done december 2017 amazon rds supports 36 db instance types 27 latest generation support different types workloads several vendors provide cloud database services similar amazon rds oracle offers oracle cloud database service supporting oracle database technology microsoft offers windows azure sql service supporting microsoft sql relational databases competitors supporting mysql include rackspace cloud databases google cloud sql hp cloud mysql xeround cloud database cleardb
|
Databases
|
ldap injection computer security ldap injection code injection technique used exploit web applications could reveal sensitive user information modify information represented ldap lightweight directory access protocol data stores ldap injection exploits security vulnerability application manipulating input parameters passed internal search add modify functions application fails properly sanitize user input possible attacker modify ldap statement ldap injection occurs user input properly sanitized used part dynamically generated ldap filter results potential manipulation ldap statements performed ldap server either view modify bypass authentication credentials ldap injection known attack prevented simple measures client supplied input must checked/sanitized characters may result malicious behavior input validation verify input checking presence special characters part ldap query language known data types legal values etc white list input validation also used detect unauthorized input passed ldap query example query constructed validate user credentials purpose logging codice_1 typical use case user would provide user credentials filter would used validate credentials however attacker enter crafted input variable codice_2 codice_3 value password finished query become codice_4 first portion query processed ldap server codice_5 always evaluates true allowing attacker gain access system without needing provide valid user credentials
|
Computer security
|
jython jython implementation python programming language designed run java platform implementation formerly known jpython 1999 jython programs import use java class except standard modules jython programs use java classes instead python modules jython includes almost modules standard python programming language distribution lacking modules implemented originally c. example user interface jython could written swing awt swt jython compiles java bytecode intermediate language either demand statically jython initially created late 1997 replace c java performance-intensive code accessed python programs moving sourceforge october 2000 python software foundation awarded grant january 2005 jython 2.5 released june 2009 recent release jython 2.7.1 released 1 july 2017 compatible python 2.7 although jython implements python language specification differences incompatibilities cpython reference implementation python version 2.2 jython including standard library released python software foundation license v2 older versions covered jython 2.0 2.1 license jpython 1.1.x software license command line interpreter available apache software license
|
Programming language topics
|
comparison c sharp java article compares two programming languages c java focus article mainly languages features comparison necessarily also consider features platforms libraries detailed comparison platforms please see comparison java .net platforms c java similar languages typed statically strongly manifestly object-oriented designed semi-interpretation runtime just-in-time compilation curly brace languages like c c++ languages statically typed class-based object orientation java primitive types special object-oriented could defined using language also share common ancestor reference types java reference types derive common root type c unified type system types besides unsafe pointers ultimately derive common root type consequently types implement methods root type extension methods defined object type apply types even primitive int literals delegates allows c unlike java support objects encapsulation reference types java compound types synonymous reference types methods defined type unless also class reference type c concepts encapsulation methods decoupled reference requirement type support methods encapsulation without reference type reference types support virtual methods specialization however languages support many built-in types copied passed value rather reference java calls types primitive types called simple types c primitive/simple types typically native support underlying processor architecture c simple types implement several interfaces consequently offer many methods directly instances types even literals c type names also merely aliases common language runtime clr types c system.int64 type exactly type long type difference former canonical .net name latter c alias java offer methods directly primitive types instead methods operate primitive values offered companion primitive wrapper classes fixed set wrapper classes exist wraps one fixed set primitive types example java long type reference type wraps primitive long type type however java c support signed integers bit widths 8 16 32 64 bits use name/aliases types except 8-bit integer called byte java sbyte signed byte c c supports unsigned addition signed integer types unsigned types byte ushort uint ulong 8 16 32 64 bit widths respectively unsigned arithmetic operating types supported well example adding two unsigned integers uints still yields uint result long signed integer java feature unsigned integer types particular java lacks primitive type unsigned byte instead java byte type sign extended common source bugs confusion unsigned integers left java deliberately james gosling believed programmers would understand unsigned arithmetic works.in programming language design one standard problems language grows complex nobody understand one little experiments tried asking people rules unsigned arithmetic c. turns nobody understands unsigned arithmetic c works obvious things people understand many people n't understand c type literal notation high-precision 28 decimal digits decimal arithmetic appropriate financial monetary calculations contrary float double data types decimal fractional numbers 0.1 represented exactly decimal representation float double representations numbers often non-terminating binary expansions making representations prone round-off errors java lacks built-in type java library feature arbitrary precision decimal type considered language type support usual arithmetic operators rather reference type must manipulated using type methods see arbitrary-size/precision numbers languages offer library-defined arbitrary-precision arithmetic types arbitrary-size integers decimal point calculations java data type arbitrary precision decimal point calculations c type working complex numbers languages number operations performed advanced numeric types limited compared built-in ieee 754 floating point types instance none arbitrary-size types support square root logarithms c allows library-defined types integrated existing types operators using custom implicit/explicit conversions operator overloading see example section integration library-defined types languages feature native char character datatype simple type although char type used bit-wise operators performed promoting char value integer value operation thus result bitwise operation numeric type character languages languages treat strings immutable objects reference type languages type contains several methods manipulate strings parse format etc languages regular expressions considered external feature implemented separate classes languages libraries define classes working dates calendars different cultures java java.util.date mutable reference type whereas c system.datetime struct value type c additionally defines timespan type working time periods languages support date time arithmetic according different cultures c allows programmer create user-defined value types using struct keyword unlike classes like standard primitives value types passed assigned value rather reference also part object either field boxed stored array without memory indirection normally exists class types value types notion null value used arrays without initialization always come implicit default constructor essentially fills struct memory space zeroes programmer define additional constructors one arguments value types virtual method tables fixed memory footprint implicitly sealed however value types frequently implement interfaces example built-in integer types implement several interfaces apart built-in primitive types java include concept value types languages define enumerations implemented fundamentally different ways enumerations one area tools designed automatically translate code two languages java c converters fail c implemented enumerations manner similar c wrappers around bit-flags implemented primitive integral types int byte short etc. performance benefits improves interaction c/c++ compiled code provides fewer features lead bugs low-level value types directly cast enumeration type allowed c language therefore seen syntactic sugar contrast java implements enumerations full featured collection instances requiring memory aiding interaction c/c++ code providing additional features reflection intrinsic behavior implementation language described table c java programmers use enumerations switch statement without conversion string primitive integer type however c disallows implicit fall-through unless case statement contain code common cause hard-to-find bugs fall-through must explicitly declared using goto statement c implements object-oriented method pointers form delegates delegate special type capture type-safe reference method reference stored delegate-type variable passed method delegate parameter later invocation c delegates support covariance contravariance hold reference signature-compatible static method instance method anonymous method lambda expression delegates confused closures inline functions concepts related reference closure/inline function must captured delegate reference useful delegate always reference inline function also reference existing static instance methods delegates form basis c events confused either delegates deliberately left java considered unnecessary detrimental language potential performance issues instead alternative mechanisms used wrapper pattern resembles delegates c allows client access one client-defined methods known interface one mechanism another use adapter objects using inner classes designers java argued better solution bound method references see also example c delegates equivalent java constructs c allows value/primitive/simple types lifted allow special null value addition type native values type lifted adding suffix type name equivalent using nullable generic type type lifted conversions implicitly defined convert values base lifted type lifted type compared null tested hasvalue also lifted operators implicitly automatically defined based non-lifted base โ exception boolean operators โ null argument propagate result java support type lifting concept built-in primitive types corresponding wrapper types support null value virtue reference types classes according java spec attempt dereference null reference must result exception thrown run-time specifically nullpointerexception would make sense dereference otherwise definition points object memory also applies attempting unbox variable wrapper type evaluates null program throw exception object unboxed thus boxed value take part subsequent computation following example illustrates different behavior c lifted*operator propagates null value operand java unboxing null reference throws exception c lifted operators defined propagate null unconditionally one operands null specifically boolean operators lifted support ternary logic thus keeping impedance sql java boolean operators support ternary logic implemented base class library c features late bound dynamic type supports no-reflection dynamic invocation interoperability dynamic languages ad-hoc binding example document object models dynamic type resolves member access dynamically runtime opposed statically/virtual compile time member lookup mechanism extensible traditional reflection fall-back mechanism several use cases dynamic type c java support late-bound type use cases c dynamic type different corresponding constructs java see also example interoperability dynamic languages java precludes pointers pointer-arithmetic within java runtime environment java language designers reasoned pointers one main features enable programmers put bugs code chose support java allow directly passing receiving objects/structures to/from underlying operating system thus need model objects/structures specific memory layout layouts frequently would involve pointers java communication underlying operating system instead based upon java native interface jni communication with/adaptation underlying operating system handled external glue layer c allow use pointers corresponding pointer arithmetic c language designers concerns pointers could potentially used bypass strict rules object access thus c default also precludes pointers however pointers needed calling many native functions pointers allowed explicit unsafe mode code blocks methods use pointers must marked unsafe keyword able use pointers compiler requires /unsafe switch allow compiling code assemblies compiled using /unsafe switch marked may execute explicitly trusted allows using pointers pointer arithmetic directly pass receive objects to/from operating system native apis using native memory layout objects also isolating potentially unsafe code specifically trusted assemblies languages references central concept instances classes reference directly evident language syntax per se languages support concept weak references instance referenced weak references eligible garbage collection references languages feature exposed associated libraries even though really core runtime feature along weak references java soft references much like weak references jvm deallocate softly-referenced objects memory needed arrays collections concepts featured languages syntax used declare access arrays identical except c added syntax declaring manipulating multidimensional arrays multidimensional arrays cases increase performance increased locality one pointer dereference instead one every dimension array case jagged arrays however since array element access multidimensional array requires multiplication/shift two dimensions advantage random access scenarios another difference entire multidimensional array allocated single application operator new jagged arrays require loops allocations every dimension however java provides syntactic construct allocating jagged array regular lengths loops multiple allocations performed virtual machine need explicit source level languages feature extensive set collection types includes various ordered unordered types lists maps/dictionaries sets etc java also supports syntax c/c++ languages allow automatic boxing unboxing i.e allow implicit casting primitive types corresponding reference types c primitive types subtypes object type java true given primitive type corresponding wrapper type specific relationship except autoboxing unboxing act syntactic sugar interchanging done intentionally maintain backward compatibility prior versions java automatic casting allowed programmer worked two separate sets types primitive types wrapper reference type hierarchy difference following consequences first c primitive types define methods override object tostring method java task accomplished primitive wrapper classes secondly java extra cast needed whenever one tries directly dereference primitive value boxed automatically expression integer 42 .tostring convert integer literal string java 42.tostring performs operation c latter one instance call primitive value 42 former one instance call object type java.lang.integer finally another difference java makes heavy use boxed types generics see languages considered curly brace languages c/c++ family overall syntaxes languages similar syntax statement expression level almost identical obvious inspiration c/c++ tradition type definition level classes interfaces minor differences exist java explicit extending classes implementing interfaces c infers kind types new class/interface derives c supports features java extent also evident syntax specifies keywords grammar rules java languages evolved language designers languages faced situations wanted extend languages new keywords syntax new keywords particular may break existing code source level i.e older code may longer compile presented compiler later version language language designers keen avoid regressions designers two languages following different paths addressing problem java language designers avoided new keywords much possible preferring instead introduce new syntactic constructs legal reuse existing keywords new contexts way n't jeopardize backward compatibility example former found loop extended accept iterable types example latter found extends especially super keywords reused specifying type bounds generics introduced java 1.5 one time java 1.4 new keyword assert introduced reserved keyword potential render previously valid code invalid instance code used assert identifier designers chose address problem four-step solution 1 introducing compiler switch indicates java 1.4 later used 2 marking assert keyword compiling java 1.4 later 3 defaulting 1.3 avoid rendering previous non 1.4 aware code invalid 4 issue warnings keyword used java 1.3 mode order allow developers change code c language designers introduced several new keywords since first version however instead defining keywords global keywords define context sensitive keywords means even introduced among others partial yield keywords c 2.0 use words identifiers still valid clash possible use keyword use identifier given context thus present c syntax fully backward compatible source code written previous version without specifying language version used c java designed ground object-oriented languages using dynamic dispatch syntax similar c++ c++ turn derives c neither language superset c c++ however c allows class definition split across several source files using feature called partial classes part must marked keyword partial parts must presented compiler part single compilation parts reference members parts parts implement interfaces one part define base class feature useful code generation scenarios user interface ui design code generator supply one part developer another part compiled together developer thus edit part without risk code generator overwriting code later time unlike class extension mechanism partial class allows circular dependencies among parts guaranteed resolved compile time java corresponding concept languages allow inner classes class defined lexically inside another class however language inner classes rather different semantics java unless inner class declared static reference instance inner class carries reference outer class result code inner class access static non-static members outer class create instance non-static inner class instance embracing outer class must named done via new new-operator introduced jdk 1.3 outerclassinstance.new outer.innerclass done class reference instance outer class c inner class conceptually normal class sense outer class acts namespace thus code inner class access non-static members outer class unless explicit reference instance outer class programmers declare inner class private allow outer class access java provides another feature called local classes anonymous classes defined within method body generally used implement interface one two methods typically event handlers however also used override virtual methods superclass methods local classes access outer method local variables declared final c satisfies use-cases providing anonymous delegates see event handling c also provides feature called anonymous types/classes rather different java concept name allows programmer instantiate class providing set names properties class expression initialize types properties inferred types expressions implicitly-declared classes derived directly object c multicast-delegates used events events provide support event-driven programming implementation observer pattern support specific syntax define events classes operators register unregister combine event handlers see information events implemented java operator overloading user-defined casts separate features aim allow new types become first-class citizens type system using features c types complex decimal integrated usual operators like addition multiplication work new types unlike c++ c restrict use operator overloading prohibiting operators new || variations compound statements like += compound operators call overloaded simple operators like -= calling java include operator overloading custom conversions order prevent abuse feature keep language simple c also includes indexers considered special case operator overloading like c++ operator parameterized get/set properties indexer property named uses one parameters indexes indices objects type java include indexers common java pattern involves writing explicit getters setters c programmer would use indexer c java object fields initialized either variable initializers expressions assigned variables defined constructors special subroutines executed object created addition java contains instance initializers anonymous blocks code arguments run explicit implicit call superclass constructor constructor executed c initializes object fields following order creating object fields may applicable e.g object static fields derived fields defined object direct class base field term fields defined one object superclasses note object representation memory contains fields defined class superclasses even fields superclasses defined private guaranteed field initializers take effect constructors called since instance constructor object class superclasses called field initializers called however potential trap object initialization virtual method called base constructor overridden method subclass may reference field defined subclass field may initialized constructor subclass contains field initialization called constructor base class java order initialization follows like c new object created calling specific constructor within constructor first statement may invocation another constructor omitted call argumentless constructor superclass added implicitly compiler otherwise either another overloaded constructor object class called explicitly superclass constructor called former case called constructor call another constructor either object class subclass chain sooner later ends call one constructors superclass another constructor called causes direct invocation superclass constructor forth object class instance variables defined object class initialized even variable initializers explicitly defined variables variables initialized default values note instance variables defined superclasses already initialized point initialized superclass constructor called either constructor code variable initializers performed constructor code implicitly default values java variable initializers executed according textual order source file finally constructor body executed ensures proper order initialization i.e fields base class finish initialization initialization fields object class begins two main potential traps java object initialization first variable initializers expressions contain method calls since methods reference variable defined class method called variable initializer reference variable defined variable initialized since initialization order corresponds textual order variable definitions variable would initialized value prescribed initializer would contain default value another potential trap method overridden derived class called base class constructor lead behavior programmer would expect object derived class created according initialization order body base class constructor executed variable initializers evaluated body derived class constructor executed overridden method called base class constructor however reference variables defined derived class yet initialized values specified initializers set derived class constructor latter issue applies c well less critical form since c methods overridable default languages mainly use garbage collection means reclaiming memory resources rather explicit deallocation memory cases object holds resources different kinds memory file handles graphical resources etc. must notified explicitly application longer uses c java offer interfaces deterministic disposal c java since java 7 feature automatic resource management statements automatically invoke disposal/close methods interfaces using special designator first parameter method c allows method act member method type first parameter extension foreign class purely syntactical extension method must declared static defined within purely static class method must obey member access restriction like method external class thus static methods break object encapsulation extension active within scopes namespace static host class imported since java 8 java similar feature called default methods methods body declared interfaces opposed c extension methods java default methods instance methods interface declare definition default methods classes implement interface optional class define method default definition used instead c extension methods java default methods allow class override default implementation extension/default method respectively languages override achieved defining method class use alternate implementation method c scope rules defines matching method found class takes precedence matching extension method java class declared implement interface default method assumed default methods implementions unless class implements method related partial classes c allows partial methods specified within partial classes partial method intentional declaration method several restrictions signature restrictions ensure definition provided class part method every call safely erased feature allows code provide large number interception points like template method gof design pattern without paying runtime overhead extension points used another class part compile time java corresponding concept methods c non-virtual default must declared virtual explicitly desired java non-static non-private methods virtual virtuality guarantees recent override method always called incurs certain runtime cost invocation invocations normally inlined require indirect call via virtual method table however jvm implementations including oracle reference implementation implement inlining commonly called virtual methods java methods virtual default although sealed using final modifier disallow overriding way let derived classes define new unrelated method name means default java explicitly enabled c new methods may defined derived class name signature base class method called superclass reference object deepest overridden implementation base class method called according specific subclass object referenced cases subclass introduces method name signature method already present base class problems occur java mean method derived class implicitly override method base class even though may intent designers either class mitigate c requires method intended override inherited method override keyword must specified otherwise method hide inherited method keyword absent compiler warning effect issued silenced specifying new keyword avoids problem arise base class extended non-private method i.e inherited part namespace whose signature already use derived class java similar compiler check form override method annotation compulsory absence compilers provide comment method overridden java possible prevent reassignment local variable method parameter using keyword applying keyword primitive type variable causes variable become immutable however applying reference type variable prevents another object assigned prevent data contained object mutated c 7 possible prevent reassignment method parameter using keyword however keyword used local variables java applying parameter prevents parameter reassigned different value still possible mutate data contained object languages support essential feature const-correctness exists c/c++ makes method constant java defines word constant arbitrarily field variables capital-only variables names separated underscore parameter considered constant although may case primitive data type immutable class like c method declared returning ienumerable ienumerator generic versions interfaces implemented using yield syntax form limited compiler-generated continuations drastically reduce code needed traverse generate sequences although code generated compiler instead feature also used implement infinite sequences e.g. sequence fibonacci numbers java equivalent feature instead generators typically defined providing specialized implementation well-known collection iterable interface compute element demand generator used statement must implement interface java.lang.iterable see also example fibonacci sequence c also explicit interface implementation allows class specifically implement methods interface separate class methods provide different implementations two methods name signature inherited two base interfaces either language method property c specified name signature multiple interfaces members clash class designed implements interfaces implementation default implement common method interfaces separate implementations needed methods serve separate purposes return values differ interfaces c explicit interface implementation solve problem though allowing different results method depending current cast object java way solve problem refactoring one interfaces avoid name clashes arguments primitive types e.g int double method passed value java whereas objects passed reference means method operates copies primitives passed instead actual variables contrary actual objects cases changed following example object string changed object class changed c possible enforce reference ref keyword similar c++ sense c. feature c particularly useful one wants create method returns one object java trying return multiple values method unsupported unless wrapper used case named ref java supports checked exceptions along unchecked exceptions c supports unchecked exceptions checked exceptions force programmer either declare exception thrown method catch thrown exception using try-catch clause checked exceptions encourage good programming practice ensuring errors dealt however anders hejlsberg chief c language architect argues extent experiment java shown worthwhile except small example programs one criticism checked exceptions encourage programmers use empty catch block catch exception e silently swallows exceptions rather letting exceptions propagate higher-level exception-handling routine cases however exception chaining applied instead re-throwing exception wrapper exception example object changed access database instead file could caught re-thrown since caller may need know inner workings object however programmers agree stance james gosling others maintain checked exceptions useful misusing caused problems silently catching exceptions possible yes must stated explicitly exception versus unchecked exceptions allow nothing default ignored code must written explicitly ignore also differences two languages treating try-finally statement finally block always executed even try block contains control-passing statements like throw return java may result unexpected behavior try block left return statement value finally block executed afterward also left return statement different value c resolves problem prohibiting control-passing statements like return break finally block common reason using try-finally blocks guard resource managing code thus guaranteeing release precious resources finally block c features using statement syntactic shorthand common scenario dispose method object using always called rather subtle difference moment stack trace created exception thrown java stack trace created moment exception created exception statement always contain constructor stack-trace matter often foo called c hand stack-trace created moment throw executed code exception contain stack-trace first throw-line catching exception two options case exception rethrown throw rethrow original exception original stack throw e would created new stack trace java allows flow control leave finally block try statement regardless way entered cause another control flow statement return terminated mid-execution example code return statement within try block causes control leave thus finally block executed actual return happens however finally block also performs return thus original return caused entered executed method returns 1 rather 0 informally speaking tries return 0 finally returns 1 c allow statements allow control flow leave finally block prematurely except throw particular return allowed goto allowed target label outside finally block continue break allowed nearest enclosing loop outside finally block field generics two languages show superficial syntactical similarity deep underlying differences generics java language-only construction implemented compiler generated classfiles include generic signatures form metadata allowing compiler compile new classes runtime knowledge generic type system generics part jvm instead generics classes methods transformed compiling via process termed type erasure compiler replaces generic types raw version inserts casts/checks appropriately client code type methods used resulting byte code contain references generic types parameters see also generics java language specification intentionally prohibits certain uses generics necessary allow implementing generics type erasure allow migration compatibility c builds support generics virtual execution system i.e. language feature language merely front-end cross-language generics support clr compiling generics verified correctness code generation implement generics deferred class-load time client code code invoking generic methods/properties fully compiled safely assume generics type-safe called reification runtime unique set type parameters generic class/method/delegate encountered first time class loader/verifier synthesize concrete class descriptor generate method implementations generation method implementations reference types considered one type reference types safely share implementations merely purpose implementing code different sets reference types still unique type descriptors method tables merely point code following list illustrates differences java c managing generics exhaustive c allows generics directly primitive types java instead allows use boxed types type parameters e.g. list integer instead list int comes cost since values need boxed/unboxed used need heap-allocated however generic type specialized array type primitive type java example list int allowed several third-party libraries implemented basic collections java backing primitive arrays preserve runtime memory optimization primitive types provide java type erasure design motivated design requirement achieve migration compatibility confused backward compatibility particular original requirement โฆ clean demonstrable migration path collections apis introduced java 2 platform designed new generic collections passable methods expected one pre-existing collection classes c generics introduced language preserving full backward compatibility preserve full migration compatibility old code pre c 2.0 runs unchanged new generics-aware runtime without recompilation migration compatibility new generic collection classes interfaces developed supplemented non-generic .net 1.x collections rather replacing addition generic collection interfaces new generic collection classes implement non-generic collection interfaces possible prevents use new generic collections pre-existing non-generic aware methods methods coded use collection classes covariance contravariance supported languages java use-site variance allows single generic class declare members using co- contravariance c define-site variance generic interfaces delegates variance unsupported directly classes supported implementation variant interfaces c also use-site covariance support methods delegates closure inline function captures variables lexical scope c supports closures anonymous methods lambda expressions full-featured closure semantics java anonymous inner classes remain preferred way emulate closures java 8 become new standard verbose construction approach also differences compared real closures notably controlled access variables enclosing scopes final members referenced java 8 however introduces lambdas fully inherit current scope fact introduce new scope reference method passed around later execution problem arises method references variables/parameters lexical scope c closures access variable/parameter lexical scope java anonymous inner classes references final members lexical scope allowed thus requiring developer mark variables make available state possibly requiring boxing c java feature special type in-line closures called lambdas anonymous methods signature body name mainly used specify local function-valued arguments calls methods technique mainly associated functional programming c unlike java allows use lambda functions way define special data structures called expression trees whether seen executable function data structure depends compiler type inference type variable parameter assigned cast lambdas expression trees play key roles language integrated query linq c namespaces similar c++ unlike package names java namespace way tied location source file strictly necessary java source file location mirror package directory structure conventional organization languages allow importing classes e.g. import java.util java allowing class referenced using name sometimes classes name exist multiple namespaces packages classes referenced using fully qualified names importing selected classes different names java allows importing single class e.g. import java.util.list c allows importing classes new local name using following syntax using console system.console also allows importing specializations classes form using intlist system.collections.generic.list int languages static import syntax allows using short name static methods/fields class e.g. allowing foo bar foo statically imported another class c static class syntax confused static inner classes java restricts class contain static methods c 3.0 introduces extension methods allow users statically add method type e.g. allowing foo.bar bar imported extension method working type foo sun microsystems java compiler requires source file name must match public class inside c allows multiple public classes file puts restrictions file name c 2.0 later allows splitting class definition several files using partial keyword source code java public class always source file c source code files logical units separation tightly related unlike java c implements conditional compilation using preprocessor directives also provides conditional attribute define methods called given compilation constant defined way assertions provided framework feature method debug.assert evaluated debug constant defined since version 1.4 java provides language feature assertions turned runtime default enabled using -enableassertions -ea switch invoking jvm languages include thread synchronization mechanisms part language syntax .net framework 4.0 new task-based programming model introduced replace existing event-based asynchronous model api based around task task classes tasks composed chained convention every method returns task name postfixed async c 5 set language compiler extensions introduced make easier work task model language extensions included notion async methods await statement make program flow appear synchronous syntactic sugar c compiler generates state-machine handles necessary continuations without developers think java supports threads since jdk 1.0 java offers high versatility running threads often called tasks done implementing functional interface java.lang.runnable interface defining single void no-args method demonstrated following example similar c java higher level mechanism working threads executors execute asynchronous tasks also manage group subprocesses threads executorservices instance handled pool executorservice instance reused hood revenant tasks possible runs many concurrent tasks programmer wants throughout life-cycle application using single executor service instance first thread-example looks like using executors executorservice instance also supports callable interface another single method interface like runnable signature contained method callable returns value way lambda expression must also return value calling method get blocks current thread waits callable completes returning value example web page content adequately support applications field mathematical financial computation several language features exist java strictfp keyword enables strict floating-point calculations region code strict floating-point calculations require even platform offers higher precision calculations intermediate results must converted single/double ensures strict floating-point calculations return exactly result platforms without strict floating-point platform implementation free use higher precision intermediate results calculation c allows implementation given hardware architecture always use higher precision intermediate results available i.e c allow programmer optionally force intermediate results use potential lower precision single/double although java floating-point arithmetic largely based ieee 754 standard binary floating-point arithmetic certain features unsupported even using strictfp modifier exception flags directed roundings abilities mandated ieee standard 754 see criticism java floating point arithmetic c provides built-in decimal type higher precision less range java/c double decimal type 128-bit data type suitable financial monetary calculations decimal type represent values ranging 1.0 ร 10 approximately 7.9 ร 10 28-29 significant digits structure uses c operator overloading decimals manipulated using operators *and like primitive data types types provided java allow arbitrary-precision representation decimal numbers integer numbers respectively java standard library classes deal complex numbers biginteger complex types provided c allow representation manipulation arbitrary-precision integers complex numbers respectively structures use c operator overloading instances manipulated using operators like primitive data types c standard library classes deal arbitrary-precision floating point numbers see software arbitrary-precision arithmetic c help mathematical applications checked unchecked operators allow enabling disabling run-time checking arithmetic overflow region code c language integrated query linq set features designed work together allow in-language querying abilities distinguishing feature c java linq consists following features java native interface jni feature allows java programs call non-java code however jni require code called follow several conventions imposes restrictions types names used means extra adaption layer legacy code java often needed adaption code must coded non-java language often c c++ java native access jna allows easier calling native code requires writing java code comes performance cost addition third party libraries provide java-component object model com bridging e.g. jacob free j-integra com proprietary .net platform invoke p/invoke offers ability allowing calls c microsoft terms unmanaged code metadata attributes programmer control exactly parameters results marshalled thus avoiding external glue code needed equivalent jni java p/invoke allows almost complete access procedural apis win32 posix limited access c++ class libraries addition .net framework also provides .net-com bridge allowing access com components first-class .net objects c also allows programmer disable normal type-checking safety features clr enables use pointer variables using feature programmer must mark code using unsafe keyword jni p/invoke unsafe code equally risky features exposing possible security holes application instability advantage unsafe managed code p/invoke jni allows programmer continue work familiar c environment accomplish tasks otherwise would require calling unmanaged code assembly program library using unsafe code must compiled special switch marked enables runtime environments take special precautions executing potentially harmful code java programming language designed execute java platform via java runtime environment jre java platform includes java virtual machine jvm common set libraries jre originally designed support interpreted execution final compiling option jre environments execute fully least partially compiled programs possibly adaptive optimization java compiler produces java bytecode upon execution bytecode loaded java runtime either interpreted directly compiled machine instructions executed c designed execute common language runtime clr clr designed execute fully compiled code c compiler produces common intermediate language instructions upon execution runtime loads code compiles machine instructions target architecture example illustrating copy text one line time one file another using languages c allows library-defined types integrated existing types operators using custom implicit/explicit conversions operator overloading illustrated following example example illustrates java c used create invoke instance class implemented another programming language deepthought class implemented using ruby programming language represents simple calculator multiply two input values b calculate method invoked addition conventional way java graalvm virtual machine capable run implemented programming language example illustrates fibonacci sequence implemented using two languages c version takes advantage c generator methods java version takes advantage stream interface method references java c examples use k r style code formatting classes methods statements
|
Programming language topics
|
biometric passport biometric passport also known e-passport epassport digital passport traditional passport embedded electronic microprocessor chip contains biometric information used authenticate identity passport holder uses contactless smart card technology including microprocessor chip computer chip antenna power chip communication embedded front back cover centre page passport passport critical information printed data page passport repeated machine readable lines stored chip public key infrastructure pki used authenticate data stored electronically passport chip making expensive difficult forge security mechanisms fully correctly implemented many countries moving towards issue biometric passports malaysia first country issue biometric passports 1998 december 2008 60 countries issuing passports increasing 120 june 2017 currently standardised biometrics used type identification system facial recognition fingerprint recognition iris recognition adopted assessment several different kinds biometrics including retinal scan document chip characteristics documented international civil aviation organization icao doc 9303 icao9303 icao defines biometric file formats communication protocols used passports digital image usually jpeg jpeg2000 format biometric feature actually stored chip comparison biometric features performed outside passport chip electronic border control systems e-borders store biometric data contactless chip includes minimum 32 kilobytes eeprom storage memory runs interface accordance iso/iec 14443 international standard amongst others standards intend interoperability different countries different manufacturers passport books national identity cards netherlands albania brazil fully icao9303 compliant biometric travel documents however others united states passport card biometric passports protection mechanisms avoid and/or detect attacks assure interoperability functionality security mechanisms listed icao german federal office information security bsi specified several test cases test specifications updated every new protocol covering details starting paper used ending chip included since introduction biometric passports several attacks presented demonstrated privacy proponents many countries question protest lack information exactly passports chip contain whether impact civil liberties main problem point data passports transferred wireless rfid technology become major vulnerability although could allow id-check computers obtain person information without physical connection may also allow anyone necessary equipment perform task personal information passport numbers chip encrypted information might wind wrong hands 15 december 2006 bbc published article british epassport citing stories adding adding future identity information society fidis network research team body security experts funded european union also come epassport scheme ... stating european governments forced document people dramatically decreases security increases risk identity theft security measures designed untrusted citizens provers scientific security community recently also addressed threats untrustworthy verifiers corrupt governmental organizations nations using poorly implemented unsecure electronic systems new cryptographic solutions private biometrics proposed mitigate threats mass theft identity scientific study yet implemented biometric passports planned except denmark ireland uk eu passports would digital imaging fingerprint scan biometrics placed rfid chips combination biometrics aims create unrivaled level security protection fraudulent identification papers technical specifications new passports established european commission specifications binding schengen agreement parties i.e eu countries except ireland uk three four european free trade association countries โ iceland norway switzerland countries obliged implement machine readable facial images passports 28 august 2006 fingerprints 29 june 2009 european data protection supervisor stated current legal framework fails address possible relevant issues triggered inherent imperfections biometric systems currently british irish biometric passports use digital image fingerprinting german passports printed 1 november 2007 contain two fingerprints one hand addition digital photograph romanian passports also contain two fingerprints one hand netherlands also takes fingerprints eu member plans store fingerprints centrally according eu requirements nations signatories schengen acquis required add fingerprint biometrics eu nations passport prices issued since may 2009 costs 7500 lekรซ โฌ60 valid 10 years contains fingerprints bearer photo data written passport issued since 5 january 2012 valid 10 years adults 5 years minors issued since june 2012 costs 1.500,00 pesos valid 10 years issued since july 2012 contains digital images fingerprints photo electronic signature passport holder valid 10 years issued since october 2005 costs au 293.. contains personal information colour photo page including digitized photograph australia use fingerprinting incoming passengers valid 10 years adults 5 years minors 16 years issued since september 2013 contains information passport holder facial features well finger palm prints issued since april 2010 costing เงณ 3450 valid 10 years electronic microprocessor chip embedded e-passport thirty-eight different security features including holographic images embossed thin film laminate change colour light demographic biometric information bearer including fingerprints ten fingers iris scan digital signature stored passport government bangladesh issues three different types e-passports diplomatic passports red cover official passports blue cover regular ordinary passports green cover issued since 15 october 2009 costing 50 km โฌ25.65 valid 10 years adults 5 years younger 18 1 june 2010 bosnia herzegovina issued first eac passport issued since 1 feb 2019 costing 550 bob usd79.13 valid 6 years bolivian epassport functions biometric passports regulations oasi issued since 8 march 2010 issued since december 2006 however december 2010 began issue passports microchips first capital brasรญlia goiรกs state since end january 2011 last available issued brazil valid 5 years adults costs r 156.07 approximately โฌ35 december 2014 federal police department extended validity document five ten years issued since 17 february 2007 bruneian epassport functions biometric passports issued since 17 july 2014 cost 5-year passport issued children aged five us 80 10-year passport issued people older five costs us 100 issued since 1 july 2013 contains bearer name gender date place birth digital portrait face issued since 26 january 2016 costing โฌ50 noted scheme gradually expand cape verdean diplomatic missions boston lisbon future issued since 2 september 2013 valid 5 years 30 january 2011 ministry foreign affairs people republic china launched trial issuance e-passports public affairs face fingerprint biometric features passport holder digitalized stored pre-installed contactless smart chip passport 1 july 2011 ministry began issuing biometric passports individuals conducting public affairs work overseas behalf chinese government ordinary biometric passports introduced ministry public security starting 15 may 2012 cost passport 200 cny approximately us 31 first-time applicants china 220 cny us 35 renewals passports issued abroad effective july 1 2017 cost biometric ordinary passport reduced 160 cny approximately us 24 first-time applicants renewal april 2017 china issued 100 million biometric ordinary passports issued since 1 september 2015 costing cop 166.000 approx us 51 issued since may 2004 however dominican biometric passports carry chip inside symbol january 2010 cost passport 1,250 dop us 35โ40 date issued since 5 february 2007 issued since 21 august 2006 issued since 23 january 2014 issued since 2010 valid 10 years adults costing 100 lari issued tehth business day day issuance cost 205 lari price photo 3 lari needs paid additionally discounts e.g 50 discount persons age 18 issued since 1 march 2010 costing ghยข 50.00โ100.00 adults children passports contain several technological characteristics biometric technology however ghanaian biometric passports carry chip inside symbol mandatory icao-standard electronic passports 2006 immigration department announced unihub limited pccw subsidiary company heading consortium suppliers including keycorp tender provide technology produce biometric passports february 2007 first biometric passport introduced cover new biometric passport remains essentially previous versions addition electronic passport logo bottom however design inner pages changed substantially design conforms document design recommendations international civil aviation organization new epassport featured 2008 stockholm challenge event finalist stockholm challenge award public administration category hong kong sar epassport design praised account multiple state-of-the-art technologies seamlessly integrated sophisticated electronic passport system e-passport system cost hksar passport hk 370 us 48 32-page passport hk 460 us 59 48-page passport issued since 23 may 2006 costing isk5100 isk1900 18 67 india recently initiated first phase deployment biometric e-passport passport holders india abroad new passports designed indigenously central passport organization india security press nashik iit kanpur passport contains security chip personal data digital images initially new passports 64kb chip photograph passport holder subsequently include holder fingerprint biometric passport tested passport readers abroad noted 4-second response time โ less us passport 10 seconds passport need carried metal jacket security reasons first needs passed reader generates access keys unlock chip data reader access india also given contract tata consultancy services issuing e-passports passport seva kendra india plans open 77 centers across country issue passports 25 june 2008 indian passport authority issued first e-passport president india pratibha patil e-passport first phase deployment initially restricted diplomatic passport holders available ordinary citizens 2017 onwards issued since 26 january 2011 passport costs rp655,000 66 48-page valid 5 years rp405,000 41 24-page passport valid 5 years issued since july 2007 diplomatic service passports 20 february 2011 ordinary biometric passports cost new passport approximately us 37 irr1,125,000 issued since 1 february 2010 costing 25,000 dinars usd20 issued since october 16 2006 issued since july 2013 2-year pilot period biometric database law optional august 2013 passport expiring 2 years replaced biometric one upon request free charge passports expiring within 2 years charged full fee program review supposed concluded 2015 postponed order minister interior later date due controversy regarding creation biometric database rather storing biometric data within passport chip practice many countries since 2015 pilot period extended 2017 may 2017 pilot period ended newly issued passports required biometric obtain biometric passport applicant must appear interior ministry office photographed special camera records information facial bone structure distance one eyes ears eyes ratio facial features one another one also fingerprinted information contained new high-tech electronic passport issued since march 2006 passports meet requirements us visa waiver program calls countries roll biometric passports 26 october 2006 kazakhstan presented concept implementing biometric passport 2009 issued since 1 september 2017 contain fingerprints facials signature including vital information icao compliant currently likely travel back kenya capture biometric data passport manufacture kenya plans invalidate old style passports 31 august 2020 issued since 31 october 2011 issued since march 2017 late 2018 older non-biometric passports longer valid use issued since september 2016 issued since august 1 2016 date introduction uncertain however enabling statute tabled november 2016 issued since 1 september 2009 issued since 2014 costs 110,000 ariary since september 2014 mandatory malagasy citizens depart country biometric passport issued since 1998 malaysia however member visa waiver program vwp first biometric passport conform standards vwp biometric document malaysian biometric passport issued several years ahead vwp requirement difference lies storage fingerprint template instead fingerprint image chip rest technologies also biometric passport designed read receiving country authorisation malaysian immigration department malaysia started issuing icao compliant passports february 2010 malaysia used issue passports validity 2 years 5 years passport 2 years validity withdrawn since january 2015 pricing malaysian passport rm 200 approximately usd 50 5 years validity rm100 approximately usd 25 senior citizens children 12 hajj pilgrims students 21 studying abroad rm100 free disabled citizens issued since 26 july 2006 new passport follows completely new design features passport holder facial fingerprint information biometric identifiers 32-page ordinary passport cost rf350 64-page ordinary passport cost rf600 children age 10 years people applying passports diplomatic missions abroad issued 32-page non-electronic ordinary passport cost rf250 issued since 2005 smom diplomatic service passports include biometric features compliant icao standards issued since 1 january 2008 costing approximately 760 mdl โฌ45 obligatory 1 january 2011 passport republic moldova biometric data contains chip holds digital information including holder signature well traditional information valid 7 years persons 7 4 years persons less 7 respectively introduced request european union safeguard borders e.u republic moldova issued since 2008 costing approximately โฌ40 issued since end 2016 issued since 6 may 2011 costs us 115.68 valid 5 years issued since 2008 trial general since 25 september 2009 costs 300dh approximately โฌ27 issued since september 2014 issuance passports suspended 40 days later resumed february 2015 issued since 8 january 2018 issued since november 2005 like australia us new zealand using facial biometric identifier two identifying factors small symbol front cover indicating electronic chip embedded passport polycarbonate leaf front version 2009 book inside chip located like australia new zealand installed smartgates airports allow new zealand epassport epassport holders 4 countries australia canada uk us clear immigration controls rapidly facial recognition technology installed immigration gates cost nz 140 applying person nz 124.50 applying onlineโavailable already holding passport adults nz 81.70 children valid five years issued december 2015 however 2015 new zealand government approved reinstatement 10-year validity period passports passports issued december 2015 valid 10 years issued since 2007 harmonized ecowas smart electronic passport issued nigerian immigrations service powered biometric technology tandem international civil aviation organization icao specifications international travels travellers data captured biometric passport accessed instantly read security agent spot globe integrated network systems configured linked centrally-coordinated passport data bank managed nigerian immigrations service issued since 2 april 2007 costs 1500 mkd c. โฌ22 issued since 2005 costs nok 450 adults c. โฌ50 nok 270 children 2007 norwegian government launched โ multi-modal โ biometric enrolment system supplied motorola motorola new system enabled multiple public agencies digitally capture store fingerprints 2d facial images signatures passports visas norwegian biometrics company idex asa begun development electronic id cards eid fingerprint security technology use throughout eu issued since end 2014 issued since 2004 without chip inside symbol compliant icao standards since 2012 may 2016 pakistan interior minister launched project officially promised epassports would available fully 2017 citizens issued since 2014 costs 100 21 february 2016 superintendencia nacional de migraciones announced first peruvian biometric passports would delivered 26 february 2016 features new cover along several security improvements order exempted visas schengen area cost pen98.50 approximately usd28 making cheapest passport latin america issued since 11 august 2009 costs โฑ950 issued since 20 april 2008 costs qr200 issued since 2006 since august 3 2018 cost 5,000 rubles approximately us 80 use printed data photo fingerprints bac-encrypted biometric passports issued 1 march 2010 valid 10 years russian biometric passports currently issued within russia consulates 1 january 2015 passports contain fingerprints issued since 27 june 2019 compliance new east african community technical specifications well international civil aviation organisation icao among new features include microchip making tamper-proof issued since 4 march 2014 saudi arabia issue biometric passports 26 march 2018 issued since 7 july 2008 costs 3.600 rsd approximately โฌ32 valid 10 years 5 years children aged 3 14 3 years children aged 3 less issued since 15 august 2006 costs 70 sgd applied online mail ica deposit box 80 sgd applied via singapore overseas mission valid 5 years passport complies us visa waiver program issued since 10 october 2006 costs us 100 applied inside somalia us 150 abroad issued since 25 august 2008 costs 55,000 us 55 validity 5 10 years issued since 3 january 2012 new passport valid five years issued since 2008 latest version issued 2014 contains contactless chip biodata card meets icao specifications issued since 10 august 2015 october 2016 new passports require thumbs scanned digital facial mapping photograph taken issuing process issued since may 2009 costs sdg250 approximately us 100 sdg200 students sdg100 children valid 5 years 7 years commercial passport issued since 4 september 2006 costs chf 140.00 adults chf 60.00 children 18 years.. since 1 march 2010 issued passports biometric containing photograph two fingerprints recorded electronically issued since 29 december 2008 costs nt 1,600 ordinary passport either 3 5 10 years validity issued since 1 february 2010 diplomats government officials passports issued 26 may 2005 1 june 2005 limited quantity 100 passports day issued thai citizens however 1 august 2005 full operational service installed thailand became first country asia issue icao compliant biometric passport issued since august 2009 cost 30,000 cfa francs togolese residing abroad price varies tunisia ministry interior stated start issuing biometric passports end year 2016 happen turkish passports compatible european union standards available since 1 june 2010 colours new biometric passports also changed accordingly regular passports claret red special passports bottle green diplomatic passports wrap black colours recently turkish minister state announced government printing new passports government minting office since private contractor failed deliver june 2018 cost issuing 10-year passport turkey โบ764 approximately us 160 turkmenistan became first country ex-ussr mid-asia region issue icao-compliant biometric passport passport available since 10 july 2008 according law ukraine supposed issue biometric passports identity cards 1 january 2013 however become available two years later january 2015 fully compatible european union standards united arab emirates ministry interior began issue biometric passports 11 december 2011 making second gcc state launch biometric passports qatar biometric version u.s. passport sometimes referred electronic passport descriptive data digitized passport photo contactless chips fingerprint information placed onto contactless chip however chip large enough 64 kilobytes inclusion biometric identifiers u.s. department state first issued passports 2006 since august 2007 issues biometric passports non-biometric passports valid expiration dates although system able perform facial-recognition match bearer image stored contactless chip desired unclear system deployed u.s. department homeland security ports entry high level security became priority united states attacks 11 september 2001 high security required cracking counterfeit passports october 2004 production stages high-tech passport commenced u.s. government printing office gpo issued awards top bidders program awards totaled roughly 1,000,000 startup development testing driving force initiative u.s enhanced border security visa entry reform act 2002 also known border security act states smartcard identity cards able replace visas foreigners travelling u.s. wish enter u.s. visa-free visa waiver program vwp required possess machine-readable passports comply international standards additionally travellers holding valid passport issued 26 october 2006 passport must biometric passport used enter u.s. visa-free vwp november 2018 hartsfield-jackson atlanta international airport delta air lines opened nation first curb-to-gate biometric terminal promised improve aviation security moving travelers faster screening uruguayan ministry interior started issue biometric passports uruguayan citizens 16 october 2015 new passport complies standards set forth visa waiver program united states uzbekistan 23 june 2009 islam karimov issued presidential decree measures improve passport system republic uzbekistan 29 december 2009 president uzbekistan signed decree change dates phased exchange populations existing passport biometric passport accordance decree biometric passports phased beginning 1 january 2011 first phase biometric passport issued employees ministries departments agencies republic individuals travel abroad outside country well citizens receive passport connection achievement certain age grounds provided law second phase rest population able get new passports period 2012 2015 issued july 2007 venezuela first latin american country issuing passports including rfid chips along major security improvements chip photo fingerprints data introduced june 2017 icao passport standards related materials open source free tools
|
Computer security
|
talarian talarian provider real-time infrastructure software part tibco veteran provider message-oriented middleware talarian member business integration group big internet protocol multicast initiative ipmi securities industry middleware council simc object management group omg internet engineering task force ietf smartsockets main product talarian real-time message-oriented middleware mom scalable fault tolerant programming model built specifically offer high-speed interprocess communication ipc multiprocessor architecture scalability reliability supports variety communication paradigms including publish-subscribe adaptive multicast redundant connections peer-to-peer rpc included part smartsockets package graphical tools monitoring debugging applications supported wide range platforms applications using smartsockets developed following languages smartsockets product tibco see acquisition january 2002 tibco acquired talarian approximately 115 million primary competitor delivery high-performance messaging solutions tibco paid 5.30 per share half stock half cash talarian outstanding shares talarian customers large end-users oems systems integrators need solutions real-time data flow supports high information volumes list famous customers
|
Distributed computing architecture
|
benjamin mako hill benjamin mako hill born december 2 1980 free software activist hacker author contributor free software developer part debian ubuntu projects well co-author three technical manuals subject debian gnu/linux 3.1 bible official ubuntu server book official ubuntu book hill assistant professor communication university washington serves member free software foundation board directors hill master degree mit media lab received phd interdepartmental program involving mit sloan school management mit media lab fall 2013 assistant professor department communication university washington also fellow mit center civic media coordinates development software civic organizing worked advisor contractor one laptop per child project speaker gnu project serves board software freedom international organization organizes software freedom day 2006 married mika matsuzaki used mathematically constrained wedding vows marriage ceremony since 1999 hill active member debian served delegate debian project leader founder coordinator debian non-profit debian custom distribution designed fill needs small non-profit organizations addition served board software public interest march 2003 july 2006 serving organisation vice-president august 2004 hill also core developer founding member ubuntu continues active contributor project addition technical responsibilities coordinated construction community around ubuntu project project community manager later ceding role jono bacon ubuntu first year half period worked full-time canonical ltd within project served community council governance board oversees non-technical aspects project october 2011 work included contributing code conduct diversity statement project addition software development hill writes extensively published academic books magazines newsletters online journals slate magazine republished one blog posts author free software project management howto canonical document managing foss projects published academic work foss anthropological sociological management software engineering perspectives written spoken intellectual property copyright collaboration generally also studied sociology community involvement web communities widely published cited projects like scratch wikipedia talked topics publicly well giving keynote address 2008 oscon hill worked several years consultant foss projects specializing coordinating releases software free open software structuring development efforts encourage community involvement spends significant amount time traveling giving talks foss intellectual property primarily europe north america previous current positions hill pursued research full-time graduate researcher mit media laboratory lab worked electronic publishing computing culture groups collaborative writing decision-making software one project selectricity award-winning voting tool received prizes grants mtv cisco fellow harvard berkman center internet society mit center civic media served advisory board wikimedia foundation advisory council open knowledge foundation board free software foundation founding member ubuntu community council 2009 2019 research symbiont award -- general symbiont
|
Operating systems
|
amstrad pc2286 amstrad 286 pc2286 launched 1989 2000 series launched professional follow pc1512/1640 2000 series consisted 2086 8086 2286 80286 2386 80386dx series used plastic case similar 1512/1640 time main computer unit power supply unit built machines bios setting battery backed however unusually used 4x aa battery mounted top based unit 2286 came 3.5 floppy drives standard side port connecting external 5 1/4 inch disk drive package contained one range monitors screen 12 14 vga mono vga color 16-bit intel 80286 cpu 12.5 mhz 1 mb ram 40 mb vga adaptor supporting mda cga hercules ega mcga evga serial parallel 5.25 inch 3.5 inch fdd mouse
|
Computer architecture
|
movhpd x86 assembly programming language movhpd name specific action performable modern x86 processors 2nd-generation streaming simd extensions sse2 action involves either copying number memory temporary space copying number temporary space memory specifically movhpd causes value 8-byte memory region either copied assigned upper half xmm register source operand either xmm register xmm memory address m64 source operand xmm register destination operand must memory address source operand memory address destination operand must xmm register note lower half xmm register unaffected operation x86 instruction listings
|
Computer architecture
|
beam erlang virtual machine beam virtual machine core erlang open telecom platform otp beam part erlang run-time system erts compiles erlang elixir source code bytecode executed beam beam bytecode files codice_1 file extension originally beam short bogdan erlang abstract machine named bogumil bogdan hausman wrote original version name may also referred bjรถrn erlang abstract machine bjรถrn gustavsson wrote maintains current version developers worked system ericsson
|
Programming language topics
|
macintosh classic macintosh classic personal computer designed manufactured sold apple computer inc. october 1990 september 1992 first macintosh sell less us 1,000 production classic prompted success macintosh plus macintosh se system specifications classic similar predecessors monochrome crt display 512ร342 pixel resolution 4 megabyte mb memory limit older macintosh computers apple decision update classic newer technology 68010 cpu higher ram capacity color display resulted criticism reviewers macworld describing nothing gloat beyond low price unexceptional ensured compatibility mac by-then healthy software base well enabled fit lower price apple intended nevertheless classic featured several improvements aging macintosh plus replaced apple low-end mac computer 25 percent faster plus included apple superdrive floppy disk drive standard classic adaptation jerry manock terry oyama 1984 macintosh 128k industrial design earlier macintosh se apple released two versions ranged price 1,000 1,500 price availability education software led classic popularity education sold alongside powerful macintosh classic ii 1991 discontinuation next year apple co-founder steve jobs left apple 1985 product development handed jean-louis gassรฉe formerly manager apple france gassรฉe consistently pushed apple product line two directions towards openness terms expandability interoperability towards higher price gassรฉe long argued apple market computers towards low end market profits thin instead concentrate high end higher profit margins illustrated concept using graph showing price/performance ratio computers low-power low-cost machines lower left high-power high-cost machines upper right high-right goal became mantra among upper management said fifty-five die referring gassรฉe goal 55 percent profit margin high-right policy led series machines ever-increasing prices original macintosh plans called system around 1,000 time morphed jef raskin original vision easy-to-use machine composing text documents jobs concept incorporating ideas gleaned trip xerox parc mac list price ballooned 2,495 price mac systems continued climb macintosh plus slightly expensive 2,599 se 2,900 3,900 depending model basic macintosh ii 40 mb hard drive least 5,500 launch price increasing late 1988 modern machines cost even macintosh iicx 5,369 iici 6,269 iifx 9,900 without monitors keyboards color crts relatively expensive late 1980s apple 14-inch 640ร480 monitor list price 999 apple adb keyboards high quality similarly expensive inexpensive machine lineup late 1980s several-year-old mac plus selling around 1,800 low-left market abandoned years earlier booming turbo xts ignored high end unix workstations likes sun sgi apple fortunes 1980s quickly reversed christmas season 1989 drove point home first decrease sales years accompanying 20 percent drop apple stock price quarter january 1990 gassรฉe resigned authority product development divided among several successors many apple engineers long pressing lower-cost options order build market share increase demand across entire price spectrum gassรฉe rush started quickly introduce series low-cost machines three market points identified low-cost machine aimed costing 1,000 low-cost machine color graphics upscale color machine small business use time would develop classic macintosh lc macintosh iisi unlike '020 '030 based models macintosh classic original macintosh startup sound macweek magazine reported july 10 1990 apple paid 1 million modular computer systems inc. subsidiary daimler-benz ag right use classic name part five-year contract apple renew contract ended macweek speculated macintosh classic would use 8 megahertz mhz motorola 68000 microprocessor display predecessors classic would priced 1,500 2,150 december 12 1990 john sculley apple ceo introduced classic press conference announcing pricing would start 1,000 saying reach new customers n't lower prices existing products redesigned computers ground features customers told us value apple new pricing strategy caused concern among investors thought would reduce profit margins brodie keast apple product marketing manager said prepared whatever takes reach people macintosh ... plan get aggressive price need release classic apple share price closed 27.75 per share 50 cents october 12 1990 far previous 12-month high 50.37 classic released europe japan concurrently united states release japan classic retailed 198,000 yen 1,523 us matching price toshiba dynabook laptop computer spending 40 million marketing classic first-time buyers apple difficulty meeting high demand apple doubled manufacturing space 1990 expanding singapore cork ireland factories classic assembled air freight rather sea shipping used speed delivery shortage caused concern among dealers blamed apple poor business planning macintosh classics lcs given scholastic software 12 weeks officially announced scholastic planned release 16 new macintosh products 1991 peter kelman scholastic publisher predicted macintosh would become school machine nineties classic sold schools 800 availability educational software led classic popularity education sector low-end model sold 1 mb memory 1.44 mb floppy drive hard disk included keyboard 999 high-end model cost 1,499 contained additional 1 mb memory expansion card 40 mb hard disk classic features several improvements macintosh plus replaced apple low-end mac computer 25 percent faster plus fast se includes apple superdrive 3.5 floppy disk drive standard superdrive read write macintosh ms-dos os/2 prodos disks also classic last compact mac use motorola 68000 central processing unit cpu classic uses system 6.0.7 operating system support versions system 7.5.5 hidden hierarchical file system hfs disk volume contained read-only memory rom includes system 6.0.3 mac classic booted system 6.0.3 holding keys boot dealers included software bundle called smartbundle classic also sold separately 349 includes t/maker writenow word processor ashton-tate full impact spreadsheet program recordholderplus database silicon beach software superpaint 2.0 paint draw program macintosh classic final adaptation jerry manock terry oyama macintosh 128k industrial design bringing back elements original retaining little snow white design language used macintosh se design remnant se stripe across front panel bezel floppy drive distinctive front bezel lines se used classic vertical lines around base replaced four horizontal vent lines reminiscent original design also curve front bezel increased radial curve front macintosh lc macintosh iisi screen brightness dial bezel also removed favor software control broad curved front bezel became signature apple product design much 1990s logic board central circuit board computer based macintosh se design size however reduced using surface mount technology 9ร5 inches 23ร13 cm half size se board redesign absence expansion slots kept manufacturing costs low lack expansion abilities along small screen size macintosh popularity desktop publishing led oddities video displays connected scsi port users seeking connect larger full- dual-page display mac classic design used 1991 classic ii succeeded classic replaced macintosh se/30 reviewers macintosh classic focused processor performance lack expansion slots liza schafer home office computing praised classic ease use price criticized display full us letter page ร 11 inches would fit full size warned required high-end graphics desktop publishing capabilities buying classic schafer concluded classic value impressive performance performance get working novel database spreadsheet pc week criticized lack faster processor stating 7.8 mhz speed adequate text applications limited graphics work suitable power users classic appropriate home computer limited computing road similarly pc user review concluded slow processor lack expansion slots macintosh classic offset low prices macweek described fine inexpensive replacement macintosh plus best embodies original macintosh vision six half years later computer gaming world skeptical doubting consumers would purchase black-and-white computer hard drive slightly faster mac plus february 1991 edition electronic learning robert mccarthy wrote teachers educational administrators software developers enthusiastic new lower cost apple macintosh computers steve taffe manager instructional strategy mecc developer publisher educational software explained excitement classic terrific โ mac low price everyone afford macintosh scholastic educational software developer also confident apple ability compete ms-dos machines stating cost-effective powerful ms-dos computers apples superior comfort-level sue talley apple manager strategic planning education said classic see going applications need fair number powerful stations color big issue talley mentioned suited writing labs basic productivity uses many schools decided buy macintosh classic lack color monitor option higher-priced macintosh lc popular apple iie card also increased lc appeal schools although classic popular first may 1992 lc 560,000 sold outselling classic 1.2 million
|
Computer architecture
|
tandy 2000 tandy 2000 personal computer introduced radio shack september 1983 based 8 mhz intel 80186 microprocessor running ms-dos comparison ibm pc xt introduced march 1983 used older 4.77 mhz 8088 processor ibm pc introduced 1984 would later use newer 6 mhz intel 80286 due 16-bit-wide data bus efficient instruction decoding 80186 tandy 2000 ran significantly faster pc compatibles slightly faster pc later ibm upgraded 80286 new pc models 8 mhz though wait states tandy 2000 company first computer built around intel x86 series microprocessor previous models used z80 68000 cpus touted compatible ibm xt tandy 2000 different enough existing pc software purely text-oriented failed work properly tandy 2000 special version ms-dos supported 768 kb ram significantly 640 kb limit imposed ibm architecture used 80-track double-sided quad-density floppy drives 720 kb capacity ibm standard time introduction tandy 2000 360 kb tandy 2000 tandy trs-80 logos case marking start phaseout trs-80 brand introduction ibm model 5150 personal computer august 1981 created entirely new market microcomputers many hardware software companies founded specifically exploit ibm microsoft new presence standard-setter small computers established manufacturers shifted focus well date tandy/radio shack small-computer market four years since august 1977 introduction trs-80 model new computer division followed october 1979 trs-80 model iiโa high-end business-oriented system 1983 trs-80 model 4 succeeded model iii replaced model consumer educational markets business segment trs-80 model 12 model 16 succeeded model ii adding higher-end features thus far tandy/radio shack computer lines occupied niches market proprietary system software applications tandy attempted monopolize software peripheral sales offering third-party products company stores ibm pc introduced nearest thing industry standard small computers cp/m-80 single manufacturer dominated 1983 ibm pc tandy discouraging third-party products halved company market share stopped profit growth tandy motive moving new ms-dos domain twofold capitalize new market leverage sales opportunities afforded solid position small computers marketing management believed many tandy customers would prefer stay tandy products inevitably seemed made jump onto burgeoning ibm/microsoft bandwagon figured company well-positioned regard large base customers consumer business markets z80-based trs-80 models i/iii/4 68000-based models 12 16 respectively tandy large presence computer retailer several thousand radio shack stores throughout us deemed advantage well pc manufacturers especially ibm relied mainly sales corporate accounts consumer retail tandy/radio shack thus company would become market leader offering hottest new trendโaffordable 16-bit computers running ms-dosโdirectly computing public therefore tandy would produce ibm-style computer running industry-standard ms-dos company decided distinguish similar products producing better computer new machine would aimed mid-price market high-end consumers low-end businesses deemed prudent order seriously cannibalize current product lines serving market segments big-name computer manufacturers made leap pc/ms-dos market half 100 popular pc programs incompatible 2000 including killer app lotus 1-2-3 tandy realize similar non-compatible computers dec ti eagle successful strategy offering high-performance pc genesis tandy 2000 technical specifications rival computers improved pc hardware matched tandy 2000 one two dimensions none offered across-the-board enhancement except noted ran ms-dos incompatible ibm pc hardware level copycat computers competed primarily lower pricing like tandy exploiting installed customer bases tandy described 2000 'next generation true 16-bit cpu speed disk storage expansion ibm pc ms-dos computers admitting 1984 many ms-dos programs support computer company stated popular sophisticated software market available either immediately next six months two models tandy 2000 introduced dual-drive floppy-only model 2,750 2000hd single floppy drive half-height 10 mb hard drive 4,250 dual-floppy model 128 kb ram hard-drive-equipped 2000hd 256 kb comparison time low-end trs-80 model 4 two floppy drives cost 1,999 high-end model 16 two floppy drives cost 4,699 tandy executive ed juge said within six months tandy realized erred 2000 early 1985 infoworld reported tandy introduced tandy 1000 found market prefers true pc compatibility 2000 incomplete compatibility tandy 2000 received lukewarm welcome market computer press inability run popular ms-dos applications anticipated tandy time accepted practice new software created new computer came market also many pc-style computers manufacturers hardware-compatible ibm pc though company supported machine hardware add-ons software tailored specially including bestsellers like lotus 1-2-3 autocad computer failed gain popular acceptance never developed would late 1986 introduction tandy 3000 tandy offered pc-style computer performance comparable tandy 2000 tandy 2000 marketed early 1988 continual price cuts eventually closed 999 remaining unsold computers converted radio shack store operations terminals coincidentally one backup plans original trs-80 model four card slots back could accept expansion boards without need open case using rail system available expansion boards/cards included tandy 2000 nominally bios-compatible ibm xt allowed well-behaved dos software run platforms however dos software time bypassed operating system bios directly accessed hardware especially video external ports achieve higher performance rendering software incompatible tandy 2000 base-model tandy 2000 supported text-mode display monochrome tandy vm-1 monitor used 8-pin video port computer rear panel text-mode address space different location third-party memory-resident software hacks remedied copying pc-compatible text-mode memory tandy 2000 text space rate 5โ10 times per second sometimes caused choppiness display produced fast text display rateโoften fast readโbut 'hold key keyboard could used pause text output bit pattern text character raster image maintained ram could modified user clever programming display ability present fine lines provided 640x400 screen resolution could accessed text mode even without optional graphics board display upgradable support pixel-addressable graphics via tandy 2000 graphics adapter circuit board fit expansion slot connector monochrome vm-1 monitor video connector rear-panel cabinet disabled expansion board installed graphics resolution 640x400 supported high intensity pixels color capability provided color graphics option set chips inserted empty sockets monochrome graphics adapter provided purpose resolution color board 640x400 non-interlaced eight colors palette sixteen available colors displayable tandy cm-1 monitor 799 particularly high-resolution colorful display day cm-1 accepted input color graphics board digital rgbi signals indicating separate red green blue signals intensity bit cga compatibility hit-or-miss three non-tandy monitors worked tandy 2000 graphics card long production original 1986โ88 mitsubishi diamond scan nippon electronics corporation nec multisync multisync gs grayscale required horizontal scan frequency tandy 2000 26.4 khz modern flat-screen multisync computer monitors sync frequencies 30 khz cm-1 monitor also digital rgb modern crt monitors analog-only tandy 2000 used quad-density 5.25 floppy disks formatted 720k format 80-track disks double-density bitrate used pc-compatibles although cp/m machines commodore 8050/8250 drives normal pcs time 40-track double-density floppy drives could read quad-density due drive heads wide read narrower tracks 1.2mb 5.25 drives introduced ibm could read quad-density disks 80-track thinner heads various utility programs dos existed allowed nonstandard formats tandy 2000 disks read much like 1.2mb drives tandy 2000 problems reliably writing 360k pc disks due smaller heads completely erasing tracks causing 40-track drives become confused residual magnetic signals outer edge track tandy distributed computer utility called pc-maker would read format 40-track disks 2000s 80-track drives readable drives ordinary pcs floppy controller tandy 2000 accept 3.5 low-density 720 kb floppy drives may 2019 abandonware site winworldpc.com available download disk image latest version ms-dos tandy 2000 includes instructions using ibm 1.2mb 5.25-inch disk drive 80-track create system disk bootable tandy 2000 5.25-inch drive procedure also used create bootable 3.5-inch system disk using ordinary 720kb 3.5-inch pc drive boot tandy 2000 5.25-inch boot drive replaced low-density 720 kb 3.5 inch pc drive keyboard entirely new design made expressly tandy 2000 would later keyboard shipped tandy 1000 successors arrangement function keys changed ibm pc/xt ten left hand side keyboard two columns five tandy among first pc manufacturers change modern arrangement twelve function keys arranged horizontally across top ibm gave nod new standard making arrangement pc-at keyboard serial port hardware completely different pc/xt pc-compatible terminal emulation software either maintain strict bios usage serial hardware else use fossil driver software wrapper virtualized serial hardware see also dec rainbow allowing terminal software work wider variety hardware several terminal programs available tandy 2000 making possible log bbs e-mail remote systems tandy 2000 required specific version ms-dos would run machine standard ms-dos pc dos generic ibm-compatibles would run tandy 2000 standard practice microsoft expectation time customized version ms-dos would prepared different machine i/o drivers designed hardware model highest version dos tandy corporation released tandy 2000 2.11.03 minor third-party patches fact modified version windows 1.0 able run tandy 2000 ms-dos tandy 2000 resided entirely ram unlike ibm pcs contained bios portion os rom complete ms-dos system bios bdos occupied 53 kb ram means ram required run applications tandy 2000 little greater however tandy 2000 fared better comparison later ibm pc-at required run ms-dos version 3.x order operate 1.2 mb floppy drives hard drive version 3 ms-dos rather larger version 2.x running tandy 2000 also proved advantageous tandy 2000 os resided entirely ram therefore could updated hacked rather less effort microsoft basic interpreter supplied computer highly customized tandy 2000 hardware particularly high-resolution color graphics although ibm produced enhanced graphics adapter little year later october 1984 microsoft basic interpreter would support greater color resolution capabilities 1988 tandy/radio shack produced print advertising featuring bill gates microsoft extolling superior performance tandy 2000 advantageous microsoft development windows 1.0 software packages released tandy 2000 included wordperfect 4.2 wp5.1 could work software patches lotus 1-2-3 ashton-tate framework dbase multimate autocad lumena time arts shareware office programs complete line microsoft language products microsoft released version xenix tandy 2000 used western digital vianet network card distributed tandy better basic tandy 2000 pc used write bbs software tandy 2000 later ported ibm pc radio shack deskmate also used tandy 2000 tandy 1000 micropro wordstar versions 3.3 4.0 would run tandy 2000 provided user ran winstall installation utility prompted type video display used selected rom bios would result functional installation none t2000 special features would operative except increased speed version lotus 1-2-3 offered tandy 2000 release 1a customized take advantage unique hardware computer including full 768k ram high resolution color graphics two extra function keys release 1a executable code 60 kb smaller later release 2 provided greater macro programming facilities extra space data additional 128 kb ram available fully expanded tandy 2000 made possible construct larger worksheets later pcs running release 2 advent machines expanded memory nearly two years following introduction tandy 2000 top performer processing large models lotus 1-2-3 tandy 2000 720 kb floppy drives distinct advantage running lotus large enough store even largest worksheets single diskette stark contrast ibm pc xt 360 kb floppy disks order store largest worksheets pc user would split save two disksโand 'd recombine memory later although xt hard drive could store large lotus worksheets single file user could rely single storage device permanent storage important data files 'd forced segment worksheets storage separate disks tandy 2000 large-capacity floppy disks made backup maintenance relatively effortless tandy dropped support tandy 2000 group users formed tandy 2000 orphans software reviews software hardware hacks shareware/freeware repository discovered amateur programmers many commercial ms-dos applications needed minor modifications function tandy 2000 unique hardware also bbs based texas extensive library compatible software available download neither bbs web-based descendant active today
|
Computer architecture
|
infinitydb infinitydb all-java embedded database engine client/server dbms extended java.util.concurrent.concurrentnavigablemap interface subinterface java.util.map deployed handheld devices servers workstations distributed settings design based proprietary lockless concurrent b-tree architecture enables client programmers reach high levels performance without risk failures new client/server version 5.0 alpha testing wrapping established embedded version provide shared access via secure remote server embedded system data stored retrieved single embedded database file using infnitydb api allows direct access variable length item spaces database client programmers construct traditional relations well specialized models directly satisfy needs dependent application limit number items database size jvm size infinitydb function smallest environment provides random access storage scaled large settings traditional relations specialized models directed database file infinitydb optimized standard relations well types data allowing client applications perform minimum one million operations per second virtual 8-core system airconcurrentmap in-memory map implements java concurrentmap interface internally uses multi-core design performance memory make fastest java map ordering performed holds medium large numbers entries airconcurrentmap iteration faster java map iterators regardless specific map type infinitydb accessed extended standard java.util.concurrent.concurrentnavigablemap via low-level 'itemspace api concurrentnavigablemap interface subinterface java.util.map special ordering concurrency methods api java.util.concurrent.concurrentskiplistmap maps may nested form complex structures maps standard semantics work internally 'tuple space maps actually stored helpers representing nothing immutable tuple prefix maps may created dynamically high speed needed access thread-safe multi-core concurrent key value types available include java primitive data types dates strings small char byte arrays 'bytestrings 'huge array indexes character long objects binary long objects plus special-purpose types 'entityclass 'attribute maps may multi-valued applications may choose use map-based access alone may mix lower-level 'itemspace access tuples map access wrapper tuple-level distinction 12 primitive data types called 'components atomic components concatenated short composites called 'items unit storage retrieval higher-level structures combine items client-devised include example unlimited size records unlimited number columns attributes complex attribute values unlimited size keys may composition components attribute values ordered sets composite components character large objects clob binary large objects blob unlimited sparse arrays higher-level structures built multiple items include key/value associations like ordered maps ordered sets entity-attribute-value nets quadruples trees dag taxonomies full-text indexes mixtures occur along custom client-defined structures itemspace may represented extended json document json printers parsers provided json documents native mapped sets items desired scale determined item prefix represents path sub-document hence entire database subtree single value represented extended json items always kept sorted json keys object always order 'itemspace represents entire database simple ordered set items state item actually stored component encoded variable-length binary form char array components self-describing standard format sorts correctly programmers deal components primitives stored data strongly typed data stored text parsed weak typing json xml parsed programmer-defined binary stream representations custom client-devised binary formats grow brittle security documentation upgrade testing versioning scaling debugging problems case java object serialization access system via basic methods store retrieve order one variable-length 'item 'tuple time speed order 1m operations/second aggregated multiple threads memory operations either standard map api codice_1 codice_2 iterators lower level codice_3 codice_4 codice_5 codice_6 codice_7 codice_8 codice_9 typical items 30 bytes uncompressed memory lob example use 1 kb items operation affects one item small data structures fast access contrast chunked access example formatting parsing entire json xml texts entire java object serialization graphs space performance scaling itemspace smooth size client-imposed multi-item structure created grows shrinks disappears on-storage performance like block-oriented b-tree blocks 4 kb log n per access block cache 2.5 mb default unlimited size often 100 mb cache grows needed performance efficiency items stored inside single b-tree prefix-compressed variable length uninterpreted sequence bytes compression b-tree may typically grow 100 gb range limits one file log files write flush infinitydb minimizes size database file four types compression prefix suffix zlib utf-8 schema upgrade structures extended modified done adding removing items new ways runtime upgrade scripts hence data model nosql schemaless besides normal java primitive types 'entityclass 'attribute types identified name number optional 'metadata mixed components item used represent tables example table given particular entityclass near front item column given different attribute items table start particular entityclass therehe one normal primitives representing 'entity like key particular attribute corresponding column finally normal primitives representing value attribute simple pattern extended time allow nested tables inside attribute nested attributes inside attributes multi-valued attributes much fixed schema elsewhere new data arrives system describes item-level granularity entityclass attribute numbers names represented extended json data displayed web-based client/server database browser viewed manipulated transferred list sorted formatted items json documents nestable tables whose visible structure determined entityclass attributes mixed items dynamic loose flexibility json formality tables combined global 'acd per-thread 'acid transactions provided infinitydb instance stores data single database file require additional log rollback files event catastrophe except power failure hardware malfunction database guaranteed consistent status completion last global commit recovery abrupt termination immediate requires slow log replay bulk loading globally transactional unlimited data size concurrent uses global transactions provide inter-thread isolation semantics 'acd rather 'acid alternatively acid transactions employ optimistic locking allow inter-thread isolation data structures grow shrink freed space reclaimed immediately made available structures systems run indefinitely without gradual space leaks long interruptions garbage reclamation phases data structure becomes empty space recycled rather leaving behind 'tombstones place holders example possibly large multi-value attribute may shrink one value becoming efficient single-valued attribute last value deleted space reclaimed including space attribute attached row attributes values row reclaimed completely well table loses rows space table reclaimed size type data structure property reference counters hence type graph incrementally collected automatically infinitydb client/server alpha-testing state features infinitydb encrypted version 5 beta-testing state features infinitydb embedded version 4 features airconcurrentmap java concurrentnavigablemap implementation features infinitydb airconcurrentmap roger l. deran designed developed infinity database engine 20 years ago holds us patent 5283894 infinity database engine first deployed intel 8088 assembly language roscor sports video editor rsve licensed nfl teams 1980s lexicon purchased rsve 1989 greatly expanded deployment types professional college sports java version 2.0 added transactionality version 3.0 added concurrency features patent pending apply infinitydb well airconcurrentmap infinity db remains active use thousands sites various kinds airconcurrentmap new uses all-java infinitydb marketed boiler bay inc. since 2002 include
|
Databases
|
lycoris company lycoris formerly redmond linux corp. started year 2000 intent make free software easy enough anyone use redmond linux founded joseph cheek entrepreneur previously worked linuxcare late 2001 merged embedded systems company deeplinux merged entity named redmond linux corporation company first product redmond linux personal easy-to-use linux desktop operating system company renamed lycoris january 2002 assets acquired mandriva june 15 2005 flagship product lycoris lycoris desktop/lx linux distribution company based maple valley washington usa lycoris currently part mandriva lycoris desktop/lx installer originally based caldera international openlinux workstation 3.1 distribution rest distribution built kernel desktop applications looked lot like microsoft windows xp right background image shipped software
|
Operating systems
|
track amp field video game track field known japan europe olympic-themed sports arcade game developed konami released 1983 japanese release sported official license 1984 summer olympics players compete series events involving alternately pressing two buttons quickly possible make onscreen character run faster followed sequel hyper sports original arcade game player uses two run buttons trackball later units replaced buttons damaged overuse one action button control athlete competing following six events event qualifying time level player must achieve advance next event failing qualify one heat running events three tries events reduce player number lives one none present his/her disposal game end players earn extra lives per 100,000 points scored game accommodate four players compete pairs running events individually others fewer four players remaining slots played computer player cpu multiplayer heats though relative performance players effect game advancing based solely qualifying times multiplayer arcade games set controls relative players going left right game two sets controls somewhat different setup left set controls players 2 4 right set players 1 3 one classic arcade games single player mode played right set controls rather left player completes six events brief medal ceremony sent back field another round higher qualifying levels however game configured conclude final event game responded repeatedly pressing run buttons high frequency players arcade version resorted various tricks rapidly swiping coin ping-pong ball buttons using metal ruler repeated struck would vibrate press buttons result arcade operators reported high rates damage buttons later versions modifications prevent actions game sold 38,000 arcade hardware units japan end 1983 also hit north america 1996 next generation listed track field series collectively number 78 top 100 games time remarking ok games play style little skill even knowledge actual sports test pure button pushing endurance nothing beat track field especially play four players allgame gave game three stars five calling physically exhausting game invented new genre addition challenging events pure originality track field offers nice cartoonish graphics rich colors smooth animation terrific rendition theme chariots fire konami continued releasing games series follow-up hyper sports seven events 100-meter freestyle skeet shooting vault archery triple jump weight lifting pole vault track field initially ported atari inc. atari 2600 console atari 8-bit computers atarisoft label also apple ii commodore 64 port atari 5200 identical atari 8-bit computer version developed 1984 cancelled zx spectrum amstrad cpc versions released part game set match ii compilation 1988 poorly regarded fans konami ported track field famicom hyper olympic included four six events afterwards converted hyper sports famicom well time including three hyper sports events one event track field time nes gained popularity united states konami retooled game release america including eight events games one cartridge original six events track field hammer throw missing place however skeet shooting archery triple jump nes version track field re-released europe 1992 track field barcelona kemco light 1992 summer olympics opening song nes version chariots fire theme vangelis also used arcade version high score screen game boy version also re-released part konami gb collection series xbox live arcade version game released xbox 360 august 8 2007 features updated graphics sounds leaderboards online play xbox live service game also appears nintendo ds altered version chariots fire theme december 18 2008 hรฉctor rodriguez california usa scored world record 95,350 points rodriguez beat 23-year-old record 95,040 points set june 30 1985 kelly kobashigawa los angeles twin galaxies 1985 video game masters tournament victoria british columbia canada twin galaxies official video game pinball book world records arcade volume lists history largest video game contest 1984 march dimes international konami/centuri track field challenge editors say 1 million contestants played track field april 30 may 26 hoping among three finalists going japan represent usa fundraiser march dimes event held aladdin castle arcades national convenience stores gary west oklahoma city u.s. finals phil britt riverside california world championship tokyo june 10 1984
|
Computer architecture
|
smtp proxy smtp proxies specialized mail transfer agents mtas similar types proxy servers pass smtp sessions mtas without using store-and-forward approach typical mta smtp proxy receives connection initiates another smtp session destination mta errors status information destination mta passed back sending mta proxy smtp proxies commonly used process filter inbound outbound email traffic smtp proxies often serve initial network-facing layer email system processing smtp connections clients forwarding data second layer mail servers smtp proxies often implement first and/or layer defence inbound anti-spam filtering system analyze messages using spam content filter antivirus program block rate limit connections using dns blacklists reputation system load balance smtp connections prevent overloading mail servers smtp proxies store messages like mail transfer agent mta reject smtp connections message content real-time away need out-of-band non delivery reports ndrs cause backscatter email serious problem internet email system certain smtp proxies implement tcp connection management otherwise known flow control help reduce damage downstream mail servers resulting spikes tcp traffic malicious smtp clients tcp connection management context smtp typically involves bandwidth throttling and/or introducing delays smtp command responses also known tarpitting slowed certain malicious sources smtp traffic spam bots tend give rather continuing deliver full email message network tarpitting challenging implement within email server since smtp connection processed slowly normal often holding precious system resources memory cpu smtp proxies implemented using lighter-weight programming techniques asynchronous io example nginx node.js netty libevent thousands connections juggled using resources much smaller number connections context full-blown store forward email server smtp proxies sometimes inserted sending mail servers local network receiving counterparts internet smtp proxies often used context order filter outgoing spam however applications domain keys identified mail dkim signing also exist smtp proxies come fundamental flavors
|
Computer security
|
citizenfour citizenfour 2014 documentary film directed laura poitras concerning edward snowden nsa spying scandal film us premiere october 10 2014 new york film festival uk premiere october 17 2014 bfi london film festival film features snowden glenn greenwald co-produced poitras mathilde bonnefoy dirk wilutzky steven soderbergh others serving executive producers citizenfour received critical acclaim upon release recipient numerous accolades including academy award best documentary feature 2015 oscars january 2013 laura poitras american documentary film director/producer working several years film monitoring programs united states result september 11 attacks receives encrypted e-mail stranger calls citizenfour offers inside information illegal wiretapping practices us national security agency nsa intelligence agencies june 2013 accompanied investigative journalist glenn greenwald guardian intelligence reporter ewen macaskill travels hong kong camera first meeting stranger hotel reveals edward snowden scenes meeting take place snowden hotel room maintains privacy shots snowden bed front mirror hotel distance form character snowden trapped political agent four days interviews june 9 snowden identity made public request media outlets begin discover location mira hong kong snowden relocates poitras room attempt elude phone calls made room facing potential extradition prosecution united states snowden schedules meeting united nations high commissioner refugees applies refugee status poitras believes followed leaves hong kong berlin june 21 us government requests hong kong government extradite snowden snowden manages depart hong kong us passport cancelled connect havana stranding sheremetyevo international airport moscow august 1 2013 russian government grants snowden temporary asylum period one year meanwhile greenwald returns home rio de janeiro speaks publicly united states utilization nsa programs foreign surveillance greenwald poitras maintain correspondence wherein express reluctance return united states throughout film offers smaller vignettes precede follow snowden hong kong interviews including william binney speaking nsa programs eventually testifying german parliament regarding nsa spying germany film closes greenwald snowden poitras meeting time russia greenwald snowden discuss new emerging details us intelligence programs careful write speak critical pieces information greenwald tears documents creating pile scraps slowly removing table born june 21 1983 elizabeth city north carolina edward snowden first became involved united states government upon enrollment army reserves spring 2004 snowden claims left program months broke legs training accident us house representatives report claims shin splints began working cia 2006 stationed diplomatic cover agency geneva switzerland 2007 nearly three years agency snowden resigned position february 2009 order begin working contractor nsa point career snowden could sense views changing watched obama advanced policies thought would reigned ... nsa intent making every conversation every form behaviour world known 2012 snowden reassigned base japan base honolulu hawaii working variety different contractors serving consultant booz allen hamilton words longer continued work nsa worked secret resist feelings regarding various programs place agency served hawaiian base approximately 15 months prior leaving united states leaking thousands classified documents 2012 poitras begun work third film 9/11 trilogy country country 2006 oath 2010 intended focus broadly topic domestic surveillance interviewed assange greenwald binney appelbaum first contacted snowden january 2013 unable establish encrypted communications greenwald flew hong kong late may 2013 course eight days filmed snowden hotel room mira hotel hong kong later traveled moscow filmed second interview snowden conducted greenwald production company praxis films involved production documentary film distributed radius twc us britdoc foundation artificial eye uk piffl media germany broadcast rights television obtained channel 4 united kingdom hbo documentary films usa norddeutscher rundfunk germany international film premiere took place october 10 2014 united states new york film festival europe documentary shown first time october 17 bfi london film festival first showing germany october 27 part leipzig film festival director laura poitras present hamburg abaton cinema preview november 4โ5 official germany premiere kino international german cinemas film running since november 6 widest release 105 theaters weekend december 12โ18 2014 premiered home box office february 23 2015 day 87th academy awards subsequently released streaming hbo go channel 4 broadcast united kingdom february 25 2015 released view-on-demand march 4 2015 citizenfour received widespread critical acclaim approval rating 96 rotten tomatoes based 144 reviews average score 8.26/10 site critics consensus reads part real-life thriller part sobering examination 21st century civil liberties citizenfour transcends ideology offer riveting must-see cinema metacritic gave film score 88 100 based 38 reviews indicating universal acclaim ronnie scheib variety wrote amount familiarity whistleblower edward snowden shocking revelations u.s. government wholesale spying citizens prepare one impact laura poitras extraordinary documentary citizenfour ... far reconstructing analyzing fait accompli film tersely records deed real time poitras fellow journalist glenn greenwald meet snowden eight-day period hong kong hotel room plot unleash bombshell shook world adapting cold language data encryption recount dramatic saga abuse power justified paranoia poitras brilliantly demonstrates information weapon cuts ways spencer ackerman writes guardian citizenfour must maddening documentary film subject pervasive global surveillance enveloping digital act spreads without visibility scenes unfold courtrooms hearing chambers hotels yet virtuosity laura poitras director architect makes 114 minutes crackle nervous energy revelation time magazine rated film 3 top 10 movies 2014 called film halloween scariest chiller vanity fair rated 4 top 10 grantland rated 3 top 10 writing chicago tribune former defense department intelligence analyst alex lyda penned negative review calling snowden narcissist patriot david edelstein reviewed film mostly favorably jocularly advised viewers n't buy ticket online credit card film site fandor published extensive survey articles reviews citizenfour updated december 25 2014 sept. 18 2018 ruled european court human rights u.k. spy agency bulk collection telecom data violated european convention human rights strasburg-based court ruled 5-2 practice failed safeguard rights privacy guaranteed human rights convention complaint brought ten groups including aclu privacy international amnesty international civil liberties groups around world december 2014 retired naval officer oil executive horace edwards kansas filed suit film producers behalf american people aiding abetting snowden leaks hollywood reporter provided legal analysis noting observers opining edwards may legal standing pursue lawsuit edwards also challenged film oscar eligibility grounds poitras 2013 short film showing greenwald interviewing snowden constituted previous release citizenfour rendering ineligible oscar rules academy rejected claim noting guardian interview appears less two minutes documentary ruled citizenfour eligible oscar consideration february 2015 filmmakers asked u.s. district court district kansas dismiss lawsuit standing jurisdictional grounds first amendment grounds citing bartnicki v. vopper edwards officially dropped case april 3 2015 dok leipzig 2014 citizenfour leipziger ring award edward snowden gave video message festival citizenfour 2015 academy award best documentary feature considered frontrunner heading awards brent lang variety called citizenfour receive nomination academy award best picture thr gregg kilday discussing prospects nominated category poitras also received several journalistic humanitarian awards reporting snowden disclosures depicted film including george polk award greenwald macaskill ridenhour truth-telling prize edward snowden carl von ossietzky medal human rights greenwald snowden henri nannen prize efforts independence press guardian washington post received pulitzer prize public service reporting poitras greenwald macaskill barton gellman poitras took many security precautions related film described military writer peter maass among others moved berlin germany detained repeatedly border controls entering us edited film germany flying directly hong kong snowden footage prevent fbi showing search warrant hard drives film footage kept encrypted drives multiple levels nested protection computer uses reading sensitive documents separated internet air gap greenwald credited complete expert level understanding story like total technical operational safety maass called poitras security skills particularly vital โ far journalistic norm โ era pervasive government spying quotes snowden stating n wake year disclosure clear unencrypted journalist-source communication unforgivably reckless bonnefoy also discussed encrypted workflow used making film adding conversation particularly confidential 'll move electronics room 'll meet somewhere outside editing room without phones film society lincoln center selects films new york film festival reported poitras changed location initial screening nyff selection committee several times case someone tracking movements committee shown rough cut sensitive material redacted nyff keep movie inclusion festival wraps mid-september kept festival schedules documents could talk openly last-minute inclusion festival main slate unprecedented event nyff tickets screenings sold within hours film ending credits unusually name several free software projects security tools without film would possible programs named include tor tails debian gnu/linux off-the-record messaging gnu privacy guard truecrypt securedrop october 2014 electronic frontier foundation published informational page software credited film november 2015 poitras prominently featured tor fund-raising campaign soundtrack consists portions nine inch nails album ghosts iโiv released creative commons license by-nc-sa 2008
|
Computer security
|
arpa host name server protocol arpa host name server protocol nameserver obsolete network protocol used translating host name internet address iana transmission control protocol tcp user datagram protocol udp port 42 nameserver port commonly used windows internet name service wins microsoft operating systems nameserver protocol used darpa trivial name server server process called tnamed provided implementations unix support nameserver protocol deprecated may available latest implementations unix operating systems domain name system dns replaced arpa host name server protocol darpa trivial name server
|
Internet protocols
|
database engine tuning advisor database engine tuning advisor deta computer software tool microsoft sql server enables database tuning improve performance query tuning indexes creating modifying deleting partition indexes configured enabled online offline tuning
|
Databases
|
windows azure caching windows azure caching in-memory distributed caching feature designed windows azure applications caching available part windows azure sdk azure managed cache in-role cache services retired microsoft recommended migration azure redis cache windows azure caching allows cloud service host caching windows azure role cache distributed across running instances role therefore amount available memory cache determined number running instances role hosts caching amount physical memory reserved caching instance two deployment topologies caching dedicated topology define worker role dedicated caching means worker role available memory used caching operating overhead following diagram shows caching dedicated topology cloud service shown three roles web1 worker1 cache1 two running instances role example cache distributed across instances dedicated cache1 role dedicated topology advantage scaling caching tier independently role cloud service best caching performance dedicated topology recommended role instances share resources application code services co-located topology use percentage available memory existing web worker roles caching following diagram shows caching co-located topology cloud service two roles web1 worker1 two running instances role example cache distributed across instances web1 role role also hosts web front-end cloud service cache configured use percentage physical memory instance web1 role co-located cache cost-effective way make use existing memory role within cloud service following sections show windows azure caching configuration code examples visual studio caching configured caching tab properties role hosts caching makes underlying changes serviceconfiguration.cscfg file settings determine topology used dedicated co-located number named caches settings roles must configured use caching one way nuget package includes modifying web.config contain properly configured datacacheclients section following example datacacheclients section specifies role hosts caching named โ cacheworker1 โ datacacheclients /datacacheclients note code samples section shown c hosting caching roles datacache class constructor used specify named cache datacacheclient section cache client settings following code shows create named cache namedcache2 using settings datacacheclient section named customclient datacache cache new datacache namedcache2 customclient following method shows use cache object retrieve data cache example user identifier userid key associated user information object code first attempts get user information cache using userid key succeed code retrieves information database query stores returned user data cache next time code run user information returned cache rather database assumes cached data expired evicted datatype getuserdata string userid following method shows update data already cache void updateuserdata string userid datatype data following call removes item cache cache.remove userid windows azure shared caching provides caching managed service unlike co-located dedicated topologies cache hosted windows azure roles single cloud service deployment instead cache provided multitenant service usage quotas service divided tiers range 128 mb 4 gb addition storage capacity tier provides increasing processor network capabilities shared caching provides way multiple cloud services access cache windows azure caching roots on-premises technology appfabric originally released one several windows azure appfabric services appfabric designation windows azure since abandoned many assembly names namespaces apis identical windows azure caching appfabric caching first release caching windows azure april 2011 provided caching managed service windows azure offering called shared caching october 2012 support added hosting caching roles within cloud service deployment called windows azure caching windows azure caching related microsoft caching technologies technologies share similar features assembly name namespace types however differences table describes technologies
|
Databases
|
openemis openemis open education management information system emis education management information system education sector main purpose collect analyze report data related management educational activities initially conceived unesco openemis serves response member states โ need area tools educational strategic planning โ open โ refers software open-source gnu gpl available royalty-free member states unesco openemis initiative launched unesco initiative line unesco effort promote emis address issues access equity quality relevance education subsequent gaps member states providing adequate decision support system since early 2000s keeping education goals adopted dakar 2000 openemis conceived royalty-free software customized meet specific needs implementing countries without conditions restrictions use purpose encouraging country-level capacity development helping countries upgrade local skills managing tool initiative coordinated unesco partnership nonprofit organization npo community systems foundation csf implementation technical support since 2012 openemis suite interrelated software solutions supports data collection survey classroom staffroom management core school integrator analysis visualizer monitoring dashboard analyzer datamanager profiles application designed provide unique standalone features support different information management requirements different levels features could customized integrated existing systems open-source solutions openemis benefits coding contributions larger community openemis initiative utilizes end-user license agreements contributor license agreements ensure maintenance standards quality assurance product remains free commercialization openemis implemented following countries nearly cases ministry education central implementation support engagement wide range stakeholders support available implementing countries aspects country implementation technical support team support activities include services policy planning analysis implementation custom software development training others needed system set may involve cost additional technical support setup configuration migration capacity building
|
Distributed computing architecture
|
anti-hijack system anti-hijack system electronic system fitted motor vehicles detect criminals hijacking although types systems becoming common newer cars caused decrease insurance premiums widely known common anti-theft systems alarms steering locks also part alarm immobiliser system approved anti-hijacking system achieve safe quick shutdown vehicle attached also mechanical anti-hijack devices company south africa diversify solutions announced research development nelson mandela university gsm based anti hijacking system system works verification process added features alcohol sensors signal jamming capabilities comes incresasing rates hijackings south africa alarming rates accidents caused driving influence texting whilst driving three basic principles systems work lockout system armed driver turns ignition key position carries specified action usually flicking hidden switch depressing brake pedal twice activated vehicle drops certain speed becomes stationary cause vehicles doors automatically lock prevent thieves stealing vehicle stopped example traffic light pedestrian crossing transponder system system always armed device usually small rfid transponder enters vehicle transmitter radius since device carried driver usually wallet pocket driver leaves immediate vicinity vehicle transponder causing system assume vehicle hijacked disable transponder concealed thief would aware system active vehicle ejected driver moved vehicle range driver usually couple meters probably common anti-hijack system central locking system uses concept demonstrated jeremy clarkson old episode bbc top gear program teased butler asking put bags mercedes-benz s600 n't give rfid transponder butler confused s600 doors would n't open tried jeremy approached transponder pocket system acknowledged unlocked car allowing jeremy simply pull door handle gain entry vehicle microswitch system always armed usually activated one vehicle doors opened closed vehicle engine running system activated driver set time limit disarm entering code vehicle takes measures system disarmed time window warn driver sounding vehicle horn every 10 seconds 30 seconds point system start sounding horn much shorter intervals usually activate vehicle hazard lights point immobiliser circuit also start rapidly pulsing 40 seconds completely disabling engine eventually bringing vehicle stop thief switches ignition position back position horn restart operate constantly hazard lights flash 60 seconds immobiliser circuit close 15 seconds rapidly pulse 15 seconds re-opening circuit allowing vehicle driven safe location immobilised hazard lights continue flash every subsequent attempt start vehicle cause horn operate 30 seconds immobilizer circuit open vehicle start hazard lights keep flashing vehicle battery drained system disarmed blocks steering shaft rotation prevent rotation steering wheel set mechanical anti-hijack device wheels turn car travel straight forward backward side back forth installing mechanical anti-hijack device lock wheels turn go car established mechanical anti-hijack device possible information photo mechanicals anti-hijack devices cars
|
Computer security
|
intermediate representation intermediate representation ir data structure code used internally compiler virtual machine represent source code ir designed conducive processing optimization translation good ir must accurate โ capable representing source code without loss information โ independent particular source target language ir may take one several forms in-memory data structure special tuple- stack-based code readable program latter case also called intermediate language canonical example found modern compilers linear human-readable text representing program transformed intermediate graph structure allows flow analysis re-arrangement creating sequence actual cpu instructions use intermediate representation allows compiler systems like gnu compiler collection llvm used many different source languages generate code many different target architectures intermediate language language abstract machine designed aid analysis computer programs term comes use compilers source code program translated form suitable code-improving transformations used generate object machine code target machine design intermediate language typically differs practical machine language three fundamental ways popular format intermediate languages three-address code term also used refer languages used intermediates high-level programming languages output object machine code output intermediate language intermediate language submitted compiler language outputs finished object machine code usually done ease process optimization increase portability using intermediate language compilers many processors operating systems c. languages used fall complexity high-level languages low-level languages assembly languages though explicitly designed intermediate language c nature abstraction assembly ubiquity de facto system language unix-like operating systems made popular intermediate language eiffel sather esterel dialects lisp lush gambit haskell glasgow haskell compiler squeak smalltalk-subset slang cython seed7 systemtap vala others make use c intermediate language variants c designed provide c features portable assembly language including c -- c intermediate language language targeting virtual machine p-code machine considered intermediate language gnu compiler collection gcc uses several intermediate languages internally simplify portability cross-compilation among languages llvm compiler framework based llvm ir intermediate language compact binary serialized representation also referred bitcode productized apple iloc intermediate language used classes compiler design simple target language static analysis tools often use intermediate representation instance radare2 toolbox binary files analysis reverse-engineering uses intermediate languages esil et reil analyze binary files
|
Programming language topics
|
kido z kidoz content discovery network designed children platform based upon sophisticated coppa compliant machine learning technology platform analyses big data knows recommend relevant content every kid based usage behaviour kidoz offer several solutions stand-alone state-of-the-art child mode app allows children explore world wide web full array mobile tablet devices safely parents may download app free google play store begin empower children explore interests independently safely https //play.google.com/store/apps/details id=com.kidoz password-protected parental control account parents set account parameters features account security enhancement content customisation tools tools addition new content kidoz businesses provides kid developers publishers sdk/js integrate within property begin monetizing safely easily kid-friendly recommendation widget creates engagement users offering free videos games apps discover enjoy advertisers may promote children content network get exposed millions targeted kids enjoy high conversion rates positive brand engagement system designed platform user-generated content content moderated approved moderation team allowed system blocks links scripts attempts lead sites content approved system internally developed around termed smart content engine filters individualizes content users based certain variables age gender languages kidoz came beta testing phase may 2009 v1.0 available 30 languages english german chinese traditional chinese simplified french greek italian japanese korean portuguese russian spanish czech dutch swedish turkish polish kidoz available free download maker website current categories websites videos games children disclosed future freemium versions include additional features premium model offering certain specialized features small monthly fee kidoz kid web environment operating system developed kido z ltd israeli start-up based tel aviv ceo gai havkin kidoz currently follows freemium model application available free download website future versions include additional features e-mail instant messaging closed network revealed next months kido โ z launch premium package offer additional tools services content
|
Operating systems
|
microsoft network monitor microsoft network monitor deprecated packet analyzer enables capturing viewing analyzing network data deciphering network protocols used troubleshoot network problems applications network microsoft network monitor 1.0 codenamed bloodhound originally designed developed raymond patch transport protocol network adapter device driver engineer microsoft lan manager development team network monitor replaced microsoft message analyzer lan manager development team one shared hardware-based analyzer time netmon conceived hardware analyzer taken test reproduce networking bug first windows prototype coded christmas holiday first 4 bytes netmon capture file format used validate file values 'rtss ray tom steve steve first four members team code originally written os/2 user interface symbol placed device driver packet buffers kept received data could dumped hex within kernel debugger netmon caused bit stir microsoft since networks e-mail encrypted time software engineers access hardware analyzers due cost netmon many engineers around company access network traffic free request microsoft two simple identification features added non-cryptographic password identification protocol named bloodhound-oriented network entity bone created named raymond patch play codename bloodhound network monitor 3 complete overhaul earlier network monitor 2.x version originally versions network monitor available microsoft products systems management server sms fully featured product public parsers available free download microsoft network monitor superseded microsoft message analyzer key features network monitor 3.4 include following
|
Computer security
|
runahead runahead technique allows microprocessor pre-process instructions cache miss cycles instead stalling pre-processed instructions used generate instruction data stream prefetches detecting cache misses would otherwise occur using idle execution resources calculate instruction data stream fetch addresses using available information independent cache miss principal hardware cost means checkpointing register file state preventing pre-processed stores modifying memory checkpointing accomplished using little hardware since results computed runahead discarded cache miss serviced time normal execution resumes using checkpointed register file state branch outcomes computed runahead mode saved shift register used highly accurate branch predictor normal operation resumes runahead initially investigated context in-order microprocessor however technique extended use order microprocessors runahead processor detects level one instruction data cache miss records instruction address faulting access enters runahead mode demand fetch missing instruction data cache line generated necessary processor checkpoints register file one several mechanisms discussed later state memory hierarchy checkpointed disabling stores store instructions allowed compute addresses check hit allowed write memory value returned cache miss known ahead time possible pre-processed instructions dependent upon invalid data denoted adding invalid inv bit every register register file runahead initiated load instruction load destination register marked inv processor continues execute instructions miss however results strictly temporary used attempt generate additional load store instruction cache misses turned prefetches designer opt allow runahead skip instructions present instruction cache understanding quality prefetches generated reduced since effect missing instructions unknown registers target instruction one source registers marked inv marked inv allows processor know register values reasonably trusted runahead mode branch instructions resolved due inv sources simply assumed direction predicted correctly branch outcomes saved shift register later use highly accurate predictions normal operation note possible perfectly track inv register values runahead mode required since runahead used optimize performance results computed runahead mode discarded fact impossible perfectly track invalid register values runahead initiated instruction cache miss instruction cache miss occurred runahead load dependent upon store inv address assumes hardware present allow store load forwarding runahead branch outcome runahead dependent upon inv register register file state restored checkpoint processor redirected original faulting fetch address fetch initiated runahead mode serviced obvious method checkpointing register file rf simply perform flash copy shadow register file backup register file brf processor enters runahead mode perform flash copy brf rf normal operation resumes simpler options available one way eliminate flash copy operations write brf rf normal operation read rf normal operation read/write brf runahead mode even aggressive approach eliminate brf rely upon forwarding paths provide modified values runahead mode checkpointing accomplished disabling register file writes modified values runahead mode provided forwarding paths
|
Computer architecture
|
shnakule shnakule biggest malware network existence averages 2000 hosts many 4357 targets users visiting trusted sites routes malware using relays exploits payload servers continually shifted new domains
|
Computer security
|
trend micro internet security trend micro internet security known pc-cillin internet security australia virus buster japan antivirus online security program developed trend micro consumer market according nss lab comparative analysis software products market 2014 trend micro internet security fastest responding new internet threats addition anti-malware web threat protection premium version software includes compatibility pcs macs android ios mobile devices parental controls identity theft prevention privacy scanner major social networking sites 25 gb cloud storage features trend micro internet security 2015 include software also includes trend micro premium security includes additional features including av-comparatives awarded trend micro three-star advanced ratingโthe highest ranking given organizationโin av-comparatives โ whole product dynamic โ real-world โ protection test 2014 av-test october 2014 gave trend micro internet security 2015 score 17 possible 18 points trend micro maximum security scored highest success rate blocking malware downloads nss labs โ 2014 consumer endpoint protection test focused socially engineered malware results based continuous series tests determine participants โ effectiveness socially engineered malware nss labs independent network testing facility security consultancy organization nss labs also found trend micro quickest time adding protection unknown threats less 15 minutes january 2016 discovered consumer version trend micro av allowed website visited users execute arbitrary code read browser passwords windows pc purportedly protected patch later issued close issue june 2014 av-test published results mobile security endurance tests assessed 30 apps six-month period trend micro โ mobile security tied highest overall score 13 13 points previous versions include january 2015 trend micro supported trend micro internet security versions 19/2011 higher pc-cillin 2000 earlier versions virus scanners without additional features pc-cillin 2002 2003 stand-alone virus scanners also included firewall component improved software โ scanning virus detection engine newer versions trend micro internet security offer additional features spyware protection antispam integrated firewall along improved scanning virus detection engine enhanced heuristics pc-cillin 2003 last stand-alone antivirus product offered trend micro 2007 company released standalone anti-malware product offered protection malicious software including viruses spyware adware
|
Computer security
|
bulk personal datasets bulk personal datasets uk government euphemism datasets containing personally identifiable information large number individuals part mass surveillance united kingdom citizens around world term first used publicly march 2015 intelligence security committee parliament subject significant controversy uk government departments programmes utilising bulk personal datasets one care.data programme department health national health service health bulk personal datasets created by-product providing direct care judicial body oversees intelligence services united kingdom investigatory powers tribunal ruled legislative framework united kingdom permit mass surveillance gchq collects analyses data bulk practice mass surveillance special report published intelligence security committee parliament also came view although found past shortcomings oversight said legal framework simplified improve transparency view supported independent reports interception communications commissioner however notable campaign groups broadsheet newspapers continue express strong views contrary others criticised viewpoints turn
|
Computer security
|
velocify velocify inc. cloud computing company headquartered el segundo california provides cloud-based intelligent sales automation software designed fast-paced sales environments velocify co-founded 2004 jeff solomon charles chase tony christopoulos company specializing software service saas company raised 3.25m series funding october 2007 rustic canyon partners initial investor may 2011 velocify named nick hedges president chief executive officer 2011 2012 nick hedges named one โ 50 influential sales lead management โ sales lead management association february 2012 velocify completed 15 million series b fundraising round led volition capital participation existing investor rustic canyon partners november 2012 velocify became marketo solution partner company announced changed name velocify leads360 june 19 2013 reflect solutions become vision future october 2017 velocify acquired ellie mae inc. leading cloud-based platform mortgage finance industry velocify offers two products sales automation solution- leadmanager integrated cloud-based dialing solution dial-iq august 2014 company released velocify salesforce offers sales automation dialing solutions within cloud-based crm platform
|
Distributed computing architecture
|
glossary backup terms subject computer backups rife jargon highly specialized terminology page glossary backup terms aims clarify meaning jargon terminology backup policy backup rotation scheme backup site backup software backup window copy backup daily backup data salvaging/recovery differential backup disaster recovery disk cloning disk image full backup hot backup incremental backup media spanning multiplexing multistreaming normal backup near store open file backup remote store restore time retention time site-to-site backup synthetic backup tape library trusted paper key virtual tape library vtl
|
Computer security
|
eulisp eulisp statically dynamically scoped lisp dialect developed loose formation industrial academic lisp users developers around europe standardizers intended create new lisp less encumbered past compared common lisp minimalist scheme another objective integrate object-oriented programming paradigm well third-generation programming language language definition process first began meeting 1985 paris took several years complete specification first implementation interpreted-only available 1990 main traits lisp-1 separate function variable namespaces common lisp object system clos style generic-function type object-oriented system named eulisp object system telos integrated ground built-in module system defined layers promote use lisp small embedded hardware educational machines supports continuations though powerfully scheme simple lightweight process mechanism threads early implementation eulisp free eventually eulisp feel successor feel youtoo interpreted compiled versions university bath united kingdom interpreter basic level eulisp level-0 written russell bradford xscheme implementation scheme david michael betz originally named euschemeeuscheme recent version renamed euxlisp avoid confusion also eu2c eulisp optimizing compiler created fraunhofer isst apply project germany dialect eulisp developed named plural eulisp eulisp parallel computing programming extensions example use classes algorithm solve towers hanoi problem
|
Programming language topics
|
semrush semrush software service saas company based boston sells online visibility marketing analytics software subscriptions founded oleg shchegolev dmitry melnikov seo tool browser extension adopting saas model software provides intelligence data including website traffic information keywords projected adwords spend site audit topic research lead generation seo-related data company customers include ebay quora booking.com hewlett packard enterprise bnp paribas oleg shchegolev dmitry melnikov started seo enthusiasts interested industry developments new technologies wanted build tool could identify market trends best industry practices sharing first findings friends local influencers people curious started using daily word mouth tool started increasing popularity community influencers grew result software first launched seodigger launched firefox extension subsequently renamed seoquake company 2007 eventually semrush 400 employees offices boston philadelphia czech republic cyprus russia 2016 reached milestone 1,000,000 users clients 100 countries april 2018 company received 40m usd funding round co-led venture capital firms greycroft e.ventures siguler guff expansion various search platforms including owned amazon microsoft baidu
|
Web technology
|
beesafe beesafe personal safety mobile app launched 2015 slovak startup location-based next generation security service notifies family members friends case user app gets danger app received numerous awards app 700 downloads 250 active logins 60 countries worldwide beesafe founded march 20 2015 peter straลพovec michal kaฤerรญk project winner ลพilina โ startup weekend 2013 startupawards.sk 2015 finalist later app released android ios marketplace whole beesafe project spot booster incubator bratislava three months beesafe entered agreement city pieลกลฅany november 2015 increase security citizen connecting mobile app police platform first city started using beesafe platform application tries help people slovak cities cities see users danger beesafe next generation corporate personal emergency app tracking application neither panic button application user โ press panic button process help call fully automated beesafe app includes silent alarm system system trigger alarm notify user โ family friends security service police user dangerous situation available android apple smartphones smart devices b beesafe app received via bona award winner slovak startup nominations
|
Operating systems
|
mini-itx mini-itx motherboard developed via technologies 2001 commonly used small-configured computer systems originally niche product designed fan-less cooling low power consumption architecture made useful home theater pc systems fan noise detract cinema experience four mounting holes mini-itx board line four holes atx-specification motherboards locations backplate expansion slot though one holes used optional earlier versions atx spec mini-itx boards therefore often used cases designed atx micro-atx atx variants desired design provides one expansion slot earlier motherboards conventionally standard 33 mhz 5v 32-bit pci slot many older case designs use riser cards even two-slot riser cards although two-slot riser cards compatible boards boards based around non-x86 processors 3.3v pci slot mini-itx 2.0 2008 boards pci-express ร16 slot boards compatible standard pci riser cards supplied older itx cases march 2001 chipset manufacturer via technologies released reference design itx motherboard promote low power c3 processor bought centaur technology combination chipsets designed robert kuo via chief r expert 215ร191 mm vt6009 itx reference board demonstrated information pc set-top box configurations later designed mini-itx specification point manufacturers took itx design shuttle jetway etc produced many itx based cube computers manufactures instead produced smaller boards based similar 229ร191 mm flexatx configuration october 2001 via announced decision create new motherboard division provide standardized infrastructure lower-cost pc iterations focus embedded devices result november 2001 release vt6010 mini-itx reference design touted information pc low cost entry level x86 computing platform manufacturers still reluctant customer response much receptive via decided manufacture sell boards april 2002 first mini-itx motherboardsโvia epia 5000 fanless 533 mhz eden processor epia 800 800 mhz c3 โwere sold industrial customers enthusiasts soon noticed advantages small size low noise power consumption started push boundaries case modding something elseโbuilding computers nearly every object imaginable sometimes even creating new cases altogether hollowed vintage computers humidors toys electronics musical instruments even 1960s-era toaster become homes relatively quiet even silent mini-itx systems capable many tasks modern desktop pc mini-itx boards primarily appeal industrial embedded pc markets majority sold bulk components integrated finished system single-purpose computing applications produced much longer sales life-cycle consumer boards original epias still available quality industrial users typically require manufacturers prototype using standard cases power supplies build enclosures volumes get high enough typical applications include playing music supermarkets powering self-service kiosks driving content digital displays via continues expand mini-itx motherboard line earlier generations included original pl133 chipset boards dubbed classic boards cle266 chipset boards adding mpeg-2 acceleration cn400 boards added mpeg-4 acceleration second generation boards featured epia mii cl pd tc ms โ tailored slightly different markets legacy via boards use x86-compatible cpus โ c3 c7 low-power eden variants newer boards featuring via nano cpu launched may 2008 manufacturers also produced boards designed around layout using via also intel amd transmeta powerpc technology intel introduced line mini-itx boards atom cpu demonstrates significant increase processing performance without added power consumption older via c3 c7 offerings helps make design viable personal computers manufacturers saw potential design followed suit even limiting atom evidenced zotac geforce 9300-itx board supports core 2 duo cpus fsb frequencies 1333 mhz two separate-channeled 800 mhz memory slots fully functional pci express 2.0 x16 slot could connect sli onboard video new wave offerings made mini-itx much popular among home users hobbyists even overclockers intel currently one mini-itx mainboard manufacturers list mechanical dimensions manuals number manufacturers released mini-itx motherboards feature embedded cpus often mobile low-tdp versions processors designed draw minimal power resulting lower tdp ideal fanless passively cooled configurations embedded applications starting lga 775 socketed intel mini-itx motherboards released intel zotac followed lga 1156 motherboards starting lga 1155 mini-itx motherboards started become mainstream many different manufacturers releasing products partly almost sandy bridge ivy bridge intel celeron pentium core series cpus integrated processor graphics eliminating need motherboard graphics discrete graphics cards trend continues lga 1150 lga 1151 cpus due limitations mini-itx design physical size lga 2011 socket mini-itx motherboards socket support single pci express expansion slot require using narrow-ilm version lga 2011 socket despite manufacturers released lga 2011 based mini-itx motherboards also mini-itx motherboards lga 2066 socket released four sodimm slots number manufacturers released several socketed amd mini-itx motherboards supporting socket am2 socket am2+ socket am3 socket fm1 socket fm2 socket fm2+ socket am1 socket am4 cpus socket am2+ am3 itx motherboards integrated motherboard graphics discrete graphics processor integrated graphics required platforms mini-itx motherboards integrated amd cpus also released motherboards often use mobile cpus passive cooling feature powerful integrated graphics compared intel counterparts makes suitable htpc ibase made first transmeta-based mini-itx motherboard mb860 board uses transmetaโข efficeonโข processors run 1.2 ghz supports sodimm ddr modules capacities 1 gb onboard 16 mb ati m7 graphics controller supports 3d games graphical intensive programs provides four usb 2.0 ports realtek 8100c 10/100mbit/s baset ethernet optional 8110s gigabit ethernet controller first powerpc motherboards produced eyetech 2005 stopped activity 2005 company acube systems made new board sam440ep primarily amigaos market cadia networks developed mini itx arm board comes arm cortex-a8 freescale i.mx53 series cpu according official website board offers ultra-low power soc variety i/o os support android linux2.6 windows embedded compact 7 kontron also developed mini itx arm board according website features arm cortex-a9 quad core 900mhz processor neon technology nvidia graphics processor 2 gb ram targeted power consumption 7w entire board appliedmicro offers xc-1 server development platform motherboard uses x-gene armv8 system chip 8 2.4 ghz cpu cores supports 128 gb ddr3 dram using 16 gb dimms baseboard management controller mini-itx standard define standard computer power supply though suggests possible options conventionally mini-itx boards use 20- 24-pin original atx power connector usually connected dc-dc converter board connects external power adapter generally vendors provide power adapter dc-dc board case boards built dc-dc converters converters also made plug directly atx connector e.g picopsu either options avoids need mount separate dc-dc converter case saving space design effort boards using full-power intel amd cpus typically use atx12v 2.x connections require case appropriate power supply cooling power-hungry chips defined atx specification power supplies atx12v connector separate 12 volts rail must idle 12 volts rail
|
Computer architecture
|
babelfy babelfy software algorithm disambiguation text written language specifically babelfy performs tasks multilingual word sense disambiguation i.e. disambiguation common nouns verbs adjectives adverbs entity linking i.e disambiguation mentions encyclopedic entities like people companies places etc. babelfy based babelnet multilingual semantic network performs disambiguation entity linking three steps result text written 271 languages supported babelnet output possibly overlapping semantic annotations
|
Computational linguistics
|
isaca isaca international professional association focused governance irs filings known information systems audit control association although isaca goes acronym isaca originated united states 1967 group individuals working auditing controls computer systems started become increasingly critical operations organizations identified need centralized source information guidance field 1969 stuart tyrnauer employee douglas aircraft company incorporated group edp auditors association edpaa tyrnauer served body founding chairman first three years 1976 association formed education foundation undertake large-scale research efforts expand knowledge value accorded fields governance control information technology association became information systems audit control association 1994 march 2016 isaca bought cmmi institute behind capability maturity model integration isaca currently serves 110,000 constituents members professionals holding isaca certifications 180 countries job titles members auditor consultant educator security professional regulator chief information officer chief information security officer internal auditor work nearly industry categories network isaca chapters 200 chapters established 80 countries chapters provide education resource sharing advocacy networking benefits csx-p isaca first cybersecurity certification introduced summer 2015 one certifications require individual work live environment real problems obtain certification specifically exam puts test takers live network real incident taking place student efforts respond incident fix problem results type score awarded
|
Computer security
|
information technology security assessment information technology security assessment security assessment explicit study locate security vulnerabilities risks assessment assessor full cooperation organization assessed organization grants access facilities provides network access outlines detailed information network etc parties understand goal study security identify improvements secure systems assessment security potentially useful security tests goal security assessment also known security audit security review network assessment ensure necessary security controls integrated design implementation project properly completed security assessment provide documentation outlining security gaps project design approved corporate security policies management address security gaps three ways management decide cancel project allocate necessary resources correct security gaps accept risk based informed risk reward analysis following methodology outline put forward effective means conducting security assessment security assessment report include following information security risk assessments like many risk assessments actually quantitative represent risk actuarially-sound manner measuring risk quantitatively significant impact prioritizing risks getting investment approval quantitative risk analysis applied security major us government study 2000 federal cio council commissioned study 100 million security investment department veterans affairs results shown quantitatively united states department veterans affairs common vendor-neutral professional certifications performing security assessment casas iii victoriano 2006 information security risk assessment model public university administrators applied research project texas state university http //ecommons.txstate.edu/arp/109/
|
Computer security
|
apache ambari apache ambari software project apache software foundation ambari enables system administrators provision manage monitor hadoop cluster also integrate hadoop existing enterprise infrastructure ambari sub-project hadoop top-level project right ambari used companies including ibm hortonworks cardinal health ebay expedia kayak.com lending club neustar macy pandora radio samsung shutterfly spotify
|
Distributed computing architecture
|
speedcoding speedcoding speedcode first high-level programming language created ibm computer language developed john backus 1953 ibm 701 support computation floating point numbers high level means symbolic aiming natural language expressivity goal opposed machine hardware instruction oriented coding idea arose difficulty programming ibm ssec machine backus hired calculate astronomical positions early 1950 speedcoding system interpreter focused ease use expense system resources provided pseudo-instructions common mathematical functions logarithms exponentiation trigonometric operations resident software analyzed pseudo-instructions one one called appropriate subroutine speedcoding also first implementation decimal input/output operations although substantially reduced effort writing many jobs running time program written help speedcoding usually ten twenty times machine code interpreter took 310 memory words 30 memory available 701
|
Programming language topics
|
nordic data grid facility nordic data grid facility ndgf common e-science infrastructure provided nordic countries denmark finland norway sweden iceland scientific computing data storage first far internationally distributed wlcg tier1 center providing computing storage services experiments cern nordic data grid facility traces history back end-2001 intrinsically related nordugrid project success latter indicated need larger pan-nordic facility storage resources high priority need addressed establishing pilot ndgf infrastructure operational 2002-2005 provided distributed storage addition nordugrid computing resources phase ndgf committed provide nordic tier1 regional computing center worldwide lhc computing grid project cern specifics tier1 internationally distributed facility nordic data grid facility present function provider nordic grid infrastructure established april 2006 nordic research councils came operation june 1 2006 initial priority live original commitment establishing nordic tier1 traditional focus storage facilities ndgf team includes software experts take part various grid middleware development 2012 ndgf became part wider initiative nordic e-infrastructure collaboration ndgf tier1 production grid facility leverages existing national computational resources grid infrastructures qualify support research groups form virtual organization vo vo provides compute resources sharing ndgf tier1 operates grid interface sharing resources currently computational resources ndgf tier1 accessible arc middleware resources also available via alien software distributed storage facility realised dcache storage management solution today dominant user community ndgf tier1 high energy physics alice atlas cms virtual organizations operation nordic tier1 together tier0 cern 12 tier1s collects stores processes data produced large hadron collider cern since 2010 ndgf tier1 part european grid infrastructure ndgf tier1 hosted nordunet 2006-2011 since 2012 hosted nordforsk many confuse ndgf nordugrid surprising especially since second phase ndgf proposed assume name nordugrid however decided distinguish mostly development-oriented project nordugrid mostly operations-oriented one ndgf rule thumb ndgf provides mostly services nordugrid provides mostly arc middleware
|
Distributed computing architecture
|
netscape navigator 9 netscape navigator 9 discontinued web browser produced netscape communications division parent aol first announced january 23 2007 ninth major release netscape line browsers aol outsourced development netscape browser 8 mercurial communications 2004 netscape navigator 9 marked first netscape browser produced in-house since netscape 7 suite also saw return classic navigator name previously used netscape heyday versions 1.0 4.08 1990s netscape navigator 9 based mozilla firefox 2.0 program first beta released june 5 2007 beta 2 july 12 beta 3 august 16 release candidate final release issued october 15 2007 december 28 2007 netscape developers announced aol would discontinue web browser february 1 2008 january 28 2008 netscape revised date march 1 2008 offered support migration flock mozilla firefox last web browser netscape series beta releases netscape navigator 9 included enhanced newsfeed support integrated netscape.com internet portal including enhanced methods discussion submission voting web pages however starting netscape navigator 9 beta 3 netscape.com integration optional certain aspects integration could manually enabled disabled integration totally removed navigator 9.0rc1 portal relaunched propeller user interface program also updated theme also later released use mozilla firefox like netscape version 8.x navigator 9 based upon mozilla firefox time version 2.0 full support firefox add-ons plugins netscape providing netscape also released features extensions firefox including site mail notifier friends activity sidebar digg tracker well netstripe new default theme netscape 9 browser also included url self-correction corrected common url misspellings improved ftp listing interface dedicated news menu integration netscape.com news portal quick link pad also included web pages could quickly added pad later viewing without adding bookmark lists navigator 9 also sees browser return multi-platform support across windows linux mac os x. netscape signature splash screen also reappeared release candidate final program unlike netscape 8 browser use internet explorer trident layout engine alternative engine option netscape navigator include newsgroup instant messaging email clients netscape 6 7 netscape however plan produce companion email client complement navigator confirmed netscape messenger 9 software development netscape advised users use netscape 7 series suites includes email client alongside navigator 9 browsing purposes new verse 8:20 easter egg book mozilla written release netscape 9 consisting thus creator looked upon beast reborn saw good could reference either re-development netscape in-house mozilla foundation contributors based user feedback netscape decided return splash screen navigator 9 september 10 2007 netscape decided give design team break let users submit idea splash screen look winning image would used splash screen final 9.0 release navigator designer would listed browser credits many designs submitted end mario herbert chosen winner design used final navigator 9 splash screen cnet download.com claimed navigator 9 neat components contained many tricks love backup browser previously used describe browser 8 bundled features version 8 removed
|
Internet protocols
|
reverse address resolution protocol reverse address resolution protocol rarp obsolete computer networking protocol used client computer request internet protocol ipv4 address computer network available link layer hardware address mac address client broadcasts request need prior knowledge network topology identities servers capable fulfilling request rarp described internet engineering task force ietf publication rfc 903 rendered obsolete bootstrap protocol bootp modern dynamic host configuration protocol dhcp support much greater feature set rarp rarp requires one server hosts maintain database mappings link layer addresses respective protocol addresses media access control mac addresses need individually configured servers administrator rarp limited serving ip addresses reverse arp differs inverse address resolution protocol inarp described rfc 2390 designed obtain ip address associated local frame relay data link connection identifier inarp used ethernet although original uses rarp overcome different protocols modern day protocols use rarp examples cisco overlay transport virtualization otv rarp used update layer 2 forwarding tables mac address moves data centers
|
Internet protocols
|
linguee linguee web service provides online dictionary number language pairs unlike similar services leo linguee incorporates search engine provides access large amounts bilingual sentence pairs found online translation aid linguee therefore differs machine translation services like babelfish similar function translation memory linguee uses specialized webcrawlers search internet appropriate bilingual texts divide parallel sentences paired sentences identified undergo automatic quality evaluation human-trained machine learning algorithm estimates quality translation user set number pairs using fuzzy search access ranking search results previous quality assurance compliance influenced search term users also rate translations manually machine learning system trained continuously addition serving bilingual web patent translated texts well eu parliament protocols laws european union eur-lex sources addition officially translated text eu sources french language service relies translated texts canadian government documents websites transcripts along canadian national institutions organisations often provide bilingual services according operator linguee offers access approximately 100 million translations concept behind linguee conceived fall 2007 former google employee dr. gereon frahling developed following year along leonard fink business idea recognized 2008 main prize competition founded federal ministry economics technology germany april 2009 web service available public linguee operated deepl gmbh formerly linguee gmbh based cologne august 2017 linguee team publicly announced launch deepl translator freely available translation service capable translating seven major european languages
|
Computational linguistics
|
qualcomm hexagon hexagon qdsp6 brand family 32-bit multi-threaded microarchitectures implementing instruction set digital signal processor dsp developed qualcomm according 2012 estimation qualcomm shipped 1.2 billion dsp cores inside system chip socs average 2.3 dsp core per soc 2011 year 1.5 billion cores planned 2012 making qdsp6 shipped architecture dsp ceva around 1 billion dsp cores shipped 2011 90 ip-licenseable dsp market hexagon architecture designed deliver performance low power variety applications features hardware assisted multithreading privilege levels long instruction word vliw single instruction multiple data simd instructions geared toward efficient signal processing cpu capable in-order dispatching 4 instructions packet 4 execution units every clock hardware multithreading implemented barrel temporal multithreading threads switched round-robin fashion cycle 600 mhz physical core presented three logical 200 mhz cores v5 hexagon v5 switched dynamic multithreading dmt thread switch l2 misses interrupt waiting special instructions hot chips 2013 qualcomm announced details hexagon 680 dsp qualcomm announced hexagon vector extensions hvx hvx designed allow significant compute workloads advanced imaging computer vision processed dsp instead cpu march 2015 qualcomm announced snapdragon neural processing engine sdk allow ai acceleration using cpu gpu hexagon dsp qualcomm snapdragon 855 contains 4th generation on-device ai engine includes hexagon 690 dsp hexagon tensor accelerator hta ai acceleration port linux hexagon runs hypervisor layer hexagon virtual machine merged 3.2 release kernel original hypervisor closed-source april 2013 minimal open-source hypervisor implementation qdsp6 v2 v3 hexagon minivm released qualcomm bsd-style license support hexagon added 3.1 release llvm tony linthicum hexagon/hvx v66 isa support added 8.0.0 release llvm also non-fsf maintained branch gcc binutils qualcomm hexagon dsps available qualcomm snapdragon soc since 2006 snapdragon s4 msm8960 newer three qdsp cores two modem subsystem one hexagon core multimedia subsystem modem cores programmed qualcomm multimedia core allowed programmed user also used femtocell processors qualcomm including fsm98xx fsm99xx fsm90xx march 2016 announced semiconductor company conexant audiosmart audio processing software integrated qualcomm hexagon six versions qdsp6 architecture released v1 2006 v2 2007โ2008 v3 2009 v4 2010โ2011 qdsp6 v5 2013 snapdragon 800 qdsp6 v6 2016 snapdragon 820 v4 20 dmips per milliwatt operating 500 mhz clock speed hexagon varies 400โ2000 mhz qdsp6 256โ350 mhz previous generation architecture qdsp5 hexagon qdsp6 pre-hexagon qdsp5 cores used modern qualcomm socs qdsp5 mostly low-end products modem qdsps often pre-hexagon shown table qdsp5 usage qdsp6 hexagon usage single instruction packet inner loop fft packet claimed qualcomm equal 29 classic risc operations includes vector add 4x 16-bit complex multiply operation hardware loop support instructions packet done cycle
|
Computer architecture
|
tor project tor project inc. massachusetts-based 501 c 3 research-education nonprofit organization founded computer scientists roger dingledine nick mathewson five others tor project primarily responsible maintaining software tor anonymity network tor project founded computer scientists roger dingledine nick mathewson five others december 2006 electronic frontier foundation eff acted tor project fiscal sponsor early years early financial supporters tor project included u.s. international broadcasting bureau internews human rights watch university cambridge google netherlands-based stichting.net october 2014 tor project hired public relations firm thomson communications order improve public image particularly regarding terms dark net hidden services educate journalists technical aspects tor may 2015 tor project ended tor cloud service december 2015 tor project announced hired shari steele former executive director electronic frontier foundation new executive director roger dingledine acting interim executive director since may 2015 remained tor project director board member later month tor project announced open technology fund sponsoring bug bounty program coordinated hackerone program initially invite-only focus finding vulnerabilities specific tor project applications may 25 2016 core developer public face tor project jacob appelbaum stepped position announced june 2 two-line statement tor following days allegations sexual mistreatment made public several people june 4 shari steele executive director tor project published statement saying recent allegations sexual mistreatment regarding appelbaum consistent rumors us hearing time asserted ... recent allegations much serious concrete anything heard previously appelbaum denounced allegations part concerted strategy damage reputation july 13 2016 complete board tor project โ meredith hoban dunn ian goldberg julius mittenzwei rabbi rob thomas wendy seltzer roger dingledine nick mathewson โ replaced matt blaze cindy cohn gabriella coleman linus nordberg megan price bruce schneier july 2016 tor project announced results seven-week investigation led private investigator allegations jacob appelbaum determined accurate shari steele noted everything power treat mr. appelbaum fairly determined allegations appear true investigation concluded many people inside outside tor project reported incidents humiliated intimidated bullied frightened jacob appelbaum several experienced unwanted sexually aggressive behavior two unnamed individuals involved inappropriate behavior longer part project institutionally despite top-down management organization working volunteers employees organizations new anti-harassment policy approved new board well conflicts interest policy procedures submitting complaints internal complaint review process initially affair caused split wider still close-knit privacy community coming appelbaum defense others presenting even allegations affair continues controversial considerable dissent within tor community 80 tor project 2 million annual budget came united states government u.s. state department broadcasting board governors national science foundation major contributors aid democracy advocates authoritarian states swedish government organizations provided 20 including ngos thousands individual sponsors dingledine said united states department defense funds similar research grant procurement contract tor executive director andrew lewman said even though accepts funds u.s. federal government tor service collaborate nsa reveal identities users june 2016 tor project received award mozilla open source support program moss award significantly enhance tor network metrics infrastructure performance stability network monitored improvements made appropriate march 2011 tor project received free software foundation 2010 award projects social benefit citation read using free software tor enabled roughly 36 million people around world experience freedom access expression internet keeping control privacy anonymity network proved pivotal dissident movements iran recently egypt september 2012 tor project received 2012 eff pioneer award along jรฉrรฉmie zimmermann andrew huang november 2012 foreign policy magazine named dingledine mathewson syverson among top 100 global thinkers making web safe whistleblowers 2014 roger dingledine nick mathewson paul syverson received usenix test time award paper titled tor second-generation onion router published proceedings 13th usenix security symposium august 2004
|
Computer security
|
finger protocol computer networking name/finger protocol finger user information protocol simple network protocols exchange human-oriented status user information name/finger protocol based request comments document december 1977 interface codice_1 codice_2 programs provide status reports particular computer system particular person network sites finger program written 1971 les earnest created program solve need users wanted information users network information logged-in useful check availability person meet probably earliest form presence information remote network users prior finger program way get information codice_3 program showed ids terminal line numbers server internal number communication line user terminal connected logged-in users earnest named program idea people would run fingers codice_3 list find looking term finger 1970s connotation snitch made finger good reminder/mnemonic semantic unix codice_2 command client protocol context finger daemon runs tcp port 79 client case remote hosts open connection port 79 ruip remote user information program started remote end connection process request local host sends ruip one line query based upon finger query specification waits ruip respond ruip receives processes query returns answer initiates close connection local host receives answer close signal proceeds close end connection finger user information protocol based finger user information protocol december 1991 typically server side protocol implemented program codice_6 finger daemon client side implemented codice_1 codice_2 programs supposed return friendly human-oriented status report either system moment particular person depth required format protocol consists mostly specifying single command line program would supply information whether user currently logged-on e-mail address full name etc well standard user information finger displays contents codice_9 codice_10 files user home directory often file maintained user contains either useful information user current activities similar micro-blogging alternatively manner humor supplying detailed information e-mail addresses full names considered acceptable convenient early days networking later considered questionable privacy security reasons finger information used hackers way initiate social engineering attack company computer security system using finger client get list company employee names email addresses phone numbers hacker call email someone company requesting information posing another employee finger daemon also several exploitable security holes crackers used break systems example 1988 morris worm exploited overflow vulnerability codice_6 among others spread finger protocol also incompatible network address translation nat private network address ranges e.g 192.168.0.0/16 used majority home office workstations connect internet routers firewalls nowadays reasons finger widely used early days internet late 1990s vast majority sites internet longer offered service implemented unix unix-like systems current versions windows finger.exe command software finger support
|
Internet protocols
|
ppc 512 amstrad ppc512 amstrad ppc640 first portable ibm pc compatible computers made amstrad released 1988 development desktop pc-1512 pc-1640 models portable computers contained elements necessary perform computing move keyboard monochrome lcd display built also space disposable batteries power pc suitable alternative power source i.e mains 12 volt vehicle power available pcs came either one two double density double side floppy disc drives ppc640 model also featured modem models supplied 'ppc organiser software ppc640 additionally supplied 'mirror ii communications software two computers similar specifications ppc512 nec v30 processor running 8 mhz 512 kib memory full-size 102-key keyboard numeric keypad built-in liquid crystal display backlit could emulate cga mda either one two 720k 3.5 floppy drives model either ppc512s ppc512d depending number drives ppc640 otherwise identical except 640 kib memory built-in 1200 baud modem unusually fast day case darker shade grey versions machine empty socket main circuit board intel 8087 coprocessor could installed permit hardware processing floating point arithmetic ppc included standard connectors rs-232 centronics cga/mda video allowing existing peripherals used signals used 8-bit isa bus also available pair expansion connectors available external card cage expansion cards four possible power sources could used physical layout components unlike laptop designs instead lid containing screen contained keyboard hinges therefore front main unit rather back lcd hinged separately folded recess top system unit one two floppy drives located right-hand side closed size ppc 45 cm wide ร 10 cm high ร 23 cm deep bank six dip switches used select whether video hardware emulated cga mda whether use internal external monitor official hard drive option docking station manufactured sold third-party manufacturers ms-dos 3.3 supplied ppcs along 'organizer memory-resident suite utilities including card file diary calculator telephone dialler addition ppc 640 supplied mirror ii communications package use built-in modem ms-dos boot disk also included utility could used switch internal display external monitor without rebooting late 1988 amstrad created desktop computer based ppc design intended home market lcd replaced rf modulator display cga video domestic television keyboard system unit combined integrated case similar original atari st amiga 500 second floppy drive bay replaced two isa slots though design case cards fitted would protrude top computer pc200 black case 'sinclair branding pc20 white branded 'amstrad pc20s also omitted rf modulator support circuitry addition ms-dos 3.3 organizer pc20/pc200 supplied gem four cga-compatible games graphical capabilities cga sound output pc speaker greatly inferior compared home computers time consequently pc20/pc200 commercial success although pc20/pc200 support today floppy disk drives built-in fdd connector uses compatible floppy disk controller zilog z765a work modification fdd connector though 720k disks
|
Computer architecture
|
ad hoc polymorphism programming languages ad hoc polymorphism kind polymorphism polymorphic functions applied arguments different types polymorphic function denote number distinct potentially heterogeneous implementations depending type argument applied also known function overloading operator overloading term ad hoc context intended pejorative refers simply fact type polymorphism fundamental feature type system contrast parametric polymorphism polymorphic functions written without mention specific type thus apply single abstract implementation number types transparent way classification introduced christopher strachey 1967 ad hoc polymorphism dispatch mechanism control moving one named function dispatched various functions without specify exact function called overloading allows multiple functions taking different types defined name compiler interpreter automatically ensures right function called way functions appending lists integers lists strings lists real numbers could written called append โand right append function would called based type lists appended differs parametric polymorphism function would need written generically work kind list using overloading possible function perform two completely different things based type input passed possible parametric polymorphism another way look overloading routine uniquely identified name combination name number order types parameters type polymorphism common object-oriented programming languages many allow operators overloaded manner similar functions see operator overloading languages dynamically typed lack ad hoc polymorphism including type classes longer function names codice_1 codice_2 etc seen advantage descriptive disadvantage overly verbose depending one point view advantage sometimes gained overloading appearance specialization e.g. function name implemented multiple different ways optimized particular data types operates provide convenient interface code needs specialized multiple situations performance reasons downside type system guarantee consistency different implementations since overloading done compile time substitute late binding found subtyping polymorphism previous section notwithstanding ways ad hoc polymorphism work consider example smalltalk language smalltalk overloading done run time methods function implementation overloaded message overloaded function resolved executed happens run time program compiled therefore polymorphism given subtyping polymorphism languages also extended functionality ad hoc polymorphism run time closer look also reveal smalltalk provides slightly different variety ad hoc polymorphism since smalltalk late bound execution model since provides objects ability handle messages understood possible go ahead implement functionality using polymorphism without explicitly overloading particular message may generally recommended practice everyday programming quite useful implementing proxies also general terms common class method constructor overloading considered polymorphism uniform languages classes regular objects smalltalk instance classes regular objects turn means messages sent classes overloaded also possible create objects behave like classes without classes inheriting hierarchy classes effective techniques used take advantage smalltalk powerful reflection capabilities similar arrangements also possible languages self newspeak imagine operator codice_3 may used following ways handle six function calls four different pieces code neededโor three strings considered lists characters thus name codice_3 actually refers three four completely different functions example overloading
|
Programming language topics
|
universal time-sharing system universal time-sharing system uts discontinued operating system xds sigma series computers succeeding batch processing monitor bpm /batch time-sharing monitor btm uts announced 1966 delays actually ship 1971 designed provide multi-programming services online interactive user programs addition batch-mode production jobs symbiont spooled i/o critical real-time processes system daemons called ghost jobs used run monitor code user space final release d00 shipped january 1973 succeeded cp-v operating system combined uts heavily batch-oriented xerox operating system xos cp-v pronounced sea-pea-five operating system compatible successor uts released august 1973 cp-v supported cpus uts plus xerox 560 cp-v offers single-stream multiprogrammed batch timesharing remote processing mode including intelligent remote batch realtime processing added release b00 april 1974 transaction processing release c00 november 1974 cp-v version c00 f00 telefile tcp-v version i00 still run sigma emulator developed 1997 cp-r control program real-time discontinued realtime operating system xerox 550 sigma 9 computer systems cp-r supports three types tasks foreground primary tasks foreground secondary tasks batch tasks 1975 xerox decided exit computer business purchased scientific data systems 1969 honeywell offered purchase xerox data systems initially provide field service support existing customer base cp-6 system including os program products developed beginning 1976 honeywell convert xerox cp-v users run honeywell equipment first beta site installed carleton university ottawa canada june 1979 three sites installed end 1979 support cp-6 transferred actc canada 1993 cp-6 systems continued run many years us canada sweden uk germany final system shutdown carleton university 2005 cp-6 accomplishments developers customers commemorated plaque community wall computer history museum mountain view california cp-v software release b00 1974 cp-v supporrted cp-6 team honeywell los angeles development center ladc 1977 thereafter xerox maintained library xerox user-written software exchange user group
|
Operating systems
|
os/7 os/7 discontinued operating system sperry univac 90/60 90/70 computer systems system first announced november 1971 univac 9700 system originally scheduled delivery march 1973. ref name= univac 90/60 90/70 univac 90/60 90/70 /ref however delivery slipped nearly year impacted 9700 marketing effort first demonstrated univac new 90/60 system october 1973 official release planned january 1974 os/7 abruptly discontinued 1975 favor vs/9 univac name rca vmos operating system os/7 multi-tasking multi-programming system utilizes roll-in roll-out capability keep cpu optimally busy
|
Operating systems
|
linux scratch linux scratch lfs type linux installation name book written gerard beekmans currently mainly maintained bruce dubbs book gives readers instructions build linux system source book available freely linux scratch site linux scratch way install working linux system building components manually naturally longer process installing pre-compiled linux distribution according linux scratch site advantages method compact flexible secure system greater understanding internal workings linux-based operating systems keep lfs small focused book beyond linux scratch blfs created presents instructions develop basic linux system created lfs introduces guides reader additions system including networking x sound printer scanner support since release 5.0 blfs book version matches lfs book version book cross linux scratch clfs focuses cross compiling including compiling headless embedded systems run linux lack resources needed compile linux clfs supports broad range processors addresses advanced techniques included lfs book cross-build toolchains multilibrary support 32 64-bit libraries side-by-side alternative instruction set architectures itanium sparc mips alpha book hardened linux scratch hlfs focuses security enhancements hardened kernel patches mandatory access control policies stack-smashing protection address space layout randomization besides main purpose creating security-focused operating system hlfs secondary goal security teaching tool automated linux scratch alfs project designed automate process creating lfs system aimed users gone lfs blfs books several times wish reduce amount work involved secondary goal act test lfs blfs books directly extracting running instructions xml sources lfs blfs books clean partition working linux system compiler essential software libraries required build lfs instead installing existing linux system one also use live cd build lfs system project formerly maintained linux scratch live cd lfs live cd contains source packages full version live cd lfs book automated building tools except minimal live cd version xfce gui environment work official lfs live cd longer maintained used build lfs version7 later however two unofficial builds used build 32-bit 64-bit kernel userspace respectively lfs 7.x first toolchain must compiled consisting tools used compile lfs like gcc glibc binutils necessary utilities root directory must changed using chroot toolchain partition start building final system one first packages compile glibc toolchain linker must adjusted link newly built glibc packages make finished system linked well chroot phase bash hashing feature turned temporary toolchain bin directory moved end path way newly compiled programs come first path new system builds new components list packages included clfs version 1.1.0 unless otherwise noted list applicable supported architectures standard build unit sbu term used initial bootstrapping system represents amount time required build first package lfs given computer creation prompted long time required build lfs system desire many users know long source tarball take build ahead time linux scratch version 6.3 first package built user gnu binutils building users encouraged measure build process using shell constructs dub time system standard build unit number known estimate time required build later packages expressed relative known sbu several packages built compilation take much longer build binutils including gnu c library rated 4.1 sbus gnu compiler collection rated 8.4 sbus unit must interpreted approximation various factors influence actual time required build package lwn.net reviewed lfs 2004 tux machines wrote review linux scratch 6.1 2005 tux machines also second part review third part source-based linux distributions
|
Operating systems
|
vmscluster vmscluster computer cluster involving group computers running openvms operating system whereas tightly coupled multiprocessor systems run single copy operating system vmscluster loosely coupled machine runs copy openvms disk storage lock manager security domain cluster-wide machines join leave vmscluster without affecting rest cluster enhanced availability vmsclusters support use dual-ported disks connected two machines storage controllers simultaneously openvms ported alpha ia-64 machines facility originally named vaxclustering renamed vmsclustering digital equipment corporation first announced vaxclusters may 1983 stage clustering required specialised communications hardware well major changes low-level subsystems vms software hardware designed jointly center cluster star coupler every node computer data storage device cluster connected one two pairs ci cables ci stands computer interconnect pair cables transmission rate 70 megabits per second high speed era using two pairs gave aggregate transmission rate 140 megabits per second redundancy case one cable failed star couplers also redundant wiring better availability ci cable connected computer via ci port could send receive packets without cpu involvement send packet cpu create small data structure memory append send queue similarly ci port would append incoming message receive queue tests showed vax-11/780 could send receive 3000 messages per second even though nominally 1-mips machine closely related mass storage control protocol mscp allowed similarly high performance mass storage subsystem addition mscp packets easily transported ci allowing remote access storage devices vaxclustering first clustering system achieve commercial success major selling point vax systems 1986 dec added vaxclustering support microvax minicomputers running ethernet instead special-purpose hardware giving high-availability advantages ci hardware local area vaxclusters provided attractive expansion path buyers low-end minicomputers later versions openvms v5.0 later supported mixed interconnect vaxclusters using ci ethernet vaxclustering dssi digital systems storage interconnect fddi among transports eventually high-bandwidth wide area networking became available clustering extended allow satellite data links long-distance terrestrial links allowed creation disaster-tolerant clusters locating single vaxcluster several diverse geographical areas cluster could survive infrastructure failures natural disasters vaxclustering greatly aided introduction terminal servers using lat protocol allowing ordinary serial terminals access host nodes via ethernet became possible terminal rapidly easily connect host node made much simpler accomplish fail user terminals one node cluster another eventually vaxclusters reached point cluster whole essentially never went rolling upgrades even allowed system operators upgrade openvms system software shutting upgrading rebooting individual nodes cluster whole continued processing cluster uptimes frequently measured years current longest uptime least sixteen years mentioned openvms also runs alpha ia-64 systems term vaxcluster replaced vmscluster gigabit ethernet common 10 gigabit ethernet introduced standard networking cables cards quite sufficient support vmsclustering
|
Distributed computing architecture
|
cpu cache cpu cache hardware cache used central processing unit cpu computer reduce average cost time energy access data main memory cache smaller faster memory closer processor core stores copies data frequently used main memory locations cpus different independent caches including instruction data caches data cache usually organized hierarchy cache levels l1 l2 l3 l4 etc. modern fast cpus specialized exceptions multiple levels cpu caches first cpus used cache one level cache unlike later level 1 caches split l1d data l1i instructions almost current cpus caches split l1 cache also l2 caches larger processors l3 caches well l2 cache usually split acts common repository already split l1 cache every core multi-core processor dedicated l2 cache usually shared cores l3 cache higher-level caches shared cores split l4 cache currently uncommon generally dynamic random-access memory dram rather static random-access memory sram separate die chip also case historically l1 bigger chips allowed integration generally cache levels possible exception last level extra level cache tends bigger optimized differently types caches exist counted towards cache size important caches mentioned translation lookaside buffer tlb part memory management unit mmu cpus caches generally sized powers two 4 8 16 etc kib mib larger non-l1 sizes although ibm z13 96 kib l1 instruction cache trying read write location main memory processor checks whether data location already cache processor read write cache instead much slower main memory modern desktop server cpus least three independent caches instruction cache speed executable instruction fetch data cache speed data fetch store translation lookaside buffer tlb used speed virtual-to-physical address translation executable instructions data single tlb provided access instructions data separate instruction tlb itlb data tlb dtlb provided data cache usually organized hierarchy cache levels l1 l2 etc see also multi-level caches however tlb cache part memory management unit mmu directly related cpu caches data transferred memory cache blocks fixed size called cache lines cache blocks cache line copied memory cache cache entry created cache entry include copied data well requested memory location called tag processor needs read write location memory first checks corresponding entry cache cache checks contents requested memory location cache lines might contain address processor finds memory location cache cache hit occurred however processor find memory location cache cache miss occurred case cache hit processor immediately reads writes data cache line cache miss cache allocates new entry copies data main memory request fulfilled contents cache make room new entry cache miss cache may evict one existing entries heuristic uses choose entry evict called replacement policy fundamental problem replacement policy must predict existing cache entry least likely used future predicting future difficult perfect method choose among variety replacement policies available one popular replacement policy least-recently used lru replaces least recently accessed entry marking memory ranges non-cacheable improve performance avoiding caching memory regions rarely re-accessed avoids overhead loading something cache without reuse cache entries may also disabled locked depending context data written cache point must also written main memory timing write known write policy write-through cache every write cache causes write main memory alternatively write-back copy-back cache writes immediately mirrored main memory cache instead tracks locations written marking dirty data locations written back main memory data evicted cache reason read miss write-back cache may sometimes require two memory accesses service one first write dirty location main memory another read new location memory also write main memory location yet mapped write-back cache may evict already dirty location thereby freeing cache space new memory location intermediate policies well cache may write-through writes may held store data queue temporarily usually multiple stores processed together reduce bus turnarounds improve bus utilization cached data main memory may changed entities e.g peripherals using direct memory access dma another core multi-core processor case copy cache may become out-of-date stale alternatively cpu multiprocessor system updates data cache copies data caches associated cpus become stale communication protocols cache managers keep data consistent known cache coherence protocols cache performance measurement become important recent times speed gap memory performance processor performance increasing exponentially cache introduced reduce speed gap thus knowing well cache able bridge gap speed processor memory becomes important especially high-performance systems cache hit rate cache miss rate play important role determining performance improve cache performance reducing miss rate becomes one necessary steps among steps decreasing access time cache also gives boost performance time taken fetch one cache line memory read latency due cache miss matters cpu run things waiting cache line cpu reaches state called stall cpus become faster compared main memory stalls due cache misses displace potential computation modern cpus execute hundreds instructions time taken fetch single cache line main memory various techniques employed keep cpu busy time including out-of-order execution cpu pentium pro later intel designs example attempts execute independent instructions instruction waiting cache miss data another technology used many processors simultaneous multithreading smt orin intel terminologyhyper-threading ht allows alternate thread use cpu core first thread waits required cpu resources become available replacement policy decides cache copy particular entry main memory go replacement policy free choose entry cache hold copy cache called fully associative extreme entry main memory go one place cache cache direct mapped many caches implement compromise entry main memory go one n places cache described n-way set associative example level-1 data cache amd athlon two-way set associative means particular location main memory cached either two locations level-1 data cache choosing right value associativity involves trade-off ten places replacement policy could mapped memory location check location cache ten cache entries must searched checking places takes power chip area potentially time hand caches associativity suffer fewer misses see conflict misses cpu wastes less time reading slow main memory general guideline doubling associativity direct mapped two-way two-way four-way effect raising hit rate doubling cache size however increasing associativity four improve hit rate much generally done reasons see virtual aliasing cpus dynamically reduce associativity caches low-power states acts power-saving measure order worse simple better complex cache organization location main memory go one entry cache therefore direct-mapped cache also called one-way set associative cache replacement policy since choice cache entry contents evict means two locations map entry may continually knock although simpler direct-mapped cache needs much larger associative one give comparable performance unpredictable let block number cache block number memory number blocks cache mapping done help equation location main memory cached either two locations cache one logical question one two simplest commonly used scheme shown right-hand diagram use least significant bits memory location index index cache memory two entries index one benefit scheme tags stored cache include part main memory address implied cache memory index since cache tags fewer bits require fewer transistors take less space processor circuit board microprocessor chip read compared faster also lru especially simple since one bit needs stored pair one advantages direct mapped cache allows simple fast speculation address computed one cache index might copy location memory known cache entry read processor continue work data finishes checking tag actually matches requested address idea processor use cached data tag match completes applied associative caches well subset tag called hint used pick one possible cache entries mapping requested address entry selected hint used parallel checking full tag hint technique works best used context address translation explained schemes suggested skewed cache index way 0 direct index way 1 formed hash function good hash function property addresses conflict direct mapping tend conflict mapped hash function less likely program suffer unexpectedly large number conflict misses due pathological access pattern downside extra latency computing hash function additionally comes time load new line evict old line may difficult determine existing line least recently used new line conflicts data different indexes way lru tracking non-skewed caches usually done per-set basis nevertheless skewed-associative caches major advantages conventional set-associative ones true set-associative cache tests possible ways simultaneously using something like content addressable memory pseudo-associative cache tests possible way one time hash-rehash cache column-associative cache examples pseudo-associative cache common case finding hit first way tested pseudo-associative cache fast direct-mapped cache much lower conflict miss rate direct-mapped cache closer miss rate fully associative cache cache row entries usually following structure data block cache line contains actual data fetched main memory tag contains part address actual data fetched main memory flag bits discussed size cache amount main memory data hold size calculated number bytes stored data block times number blocks stored cache tag flag error correction code bits included size although affect physical area cache effective memory address goes along cache line memory block split msb lsb tag index block offset index describes cache set data put index length formula_1 bits cache sets block offset specifies desired data within stored data block within cache row typically effective address bytes block offset length formula_2 bits number bytes per data block tag contains significant bits address checked rows current set set retrieved index see set contains requested address cache hit occurs tag length bits follows authors refer block offset simply offset displacement original pentium 4 processor four-way set associative l1 data cache 8 kib size 64-byte cache blocks hence 8 kib 64 128 cache blocks number sets equal number cache blocks divided number ways associativity leads 128 4 32 sets hence 2 32 different indices 2 64 possible offsets since cpu address 32 bits wide implies 32 5 6 21 bits tag field original pentium 4 processor also eight-way set associative l2 integrated cache 256 kib size 128-byte cache blocks implies 32 8 7 17 bits tag field instruction cache requires one flag bit per cache row entry valid bit valid bit indicates whether cache block loaded valid data power-up hardware sets valid bits caches invalid systems also set valid bit invalid times multi-master bus snooping hardware cache one processor hears address broadcast processor realizes certain data blocks local cache stale marked invalid data cache typically requires two flag bits per cache line valid bit dirty bit dirty bit set indicates associated cache line changed since read main memory dirty meaning processor written data line new value propagated way main memory cache miss failed attempt read write piece data cache results main memory access much longer latency three kinds cache misses instruction read miss data read miss data write miss cache read misses instruction cache generally cause largest delay processor least thread execution wait stall instruction fetched main memory cache read misses data cache usually cause smaller delay instructions dependent cache read issued continue execution data returned main memory dependent instructions resume execution cache write misses data cache generally cause shortest delay write queued limitations execution subsequent instructions processor continue queue full detailed introduction types misses see cache performance measurement metric general purpose cpus implement form virtual memory summarize either program running machine sees simplified address space contains code data program programs run common virtual address space program executes calculating comparing reading writing addresses virtual address space rather addresses physical address space making programs simpler thus easier write virtual memory requires processor translate virtual addresses generated program physical addresses main memory portion processor translation known memory management unit mmu fast path mmu perform translations stored translation lookaside buffer tlb cache mappings operating system page table segment table purposes present discussion three important features address translation early virtual memory systems slow required access page table held main memory every programmed access main memory caches effectively cut speed memory access half first hardware cache used computer system actually data instruction cache rather tlb caches divided four types based whether index tag correspond physical virtual addresses speed recurrence load latency crucial cpu performance modern level-1 caches virtually indexed least allows mmu tlb lookup proceed parallel fetching data cache ram virtual indexing best choice cache levels cost dealing virtual aliases grows cache size result level-2 larger caches physically indexed caches historically used virtual physical addresses cache tags although virtual tagging uncommon tlb lookup finish cache ram lookup physical address available time tag compare need virtual tagging large caches tend physically tagged small low latency caches virtually tagged recent general-purpose cpus virtual tagging superseded vhints described cache relies virtual indexing tagging becomes inconsistent virtual address mapped different physical addresses homonym solved using physical address tagging storing address space identifier cache line however latter approach help synonym problem several cache lines end storing data physical address writing locations may update one location cache leaving others inconsistent data issue may solved using non-overlapping memory layouts different address spaces otherwise cache part must flushed mapping changes great advantage virtual tags associative caches allow tag match proceed virtual physical translation done however coherence probes evictions present physical address action hardware must means converting physical addresses cache index generally storing physical tags well virtual tags comparison physically tagged cache need keep virtual tags simpler virtual physical mapping deleted tlb cache entries virtual addresses flushed somehow alternatively cache entries allowed pages mapped tlb entries flushed access rights pages changed page table also possible operating system ensure virtual aliases simultaneously resident cache operating system makes guarantee enforcing page coloring described early risc processors sparc rs/6000 took approach used recently hardware cost detecting evicting virtual aliases fallen software complexity performance penalty perfect page coloring risen useful distinguish two functions tags associative cache used determine way entry set select used determine cache hit missed second function must always correct permissible first function guess get wrong answer occasionally processors e.g early sparcs caches virtual physical tags virtual tags used way selection physical tags used determining hit miss kind cache enjoys latency advantage virtually tagged cache simple software interface physically tagged cache bears added cost duplicated tags however also miss processing alternate ways cache line indexed probed virtual aliases matches evicted extra area latency mitigated keeping virtual hints cache entry instead virtual tags hints subset hash virtual tag used selecting way cache get data physical tag like virtually tagged cache may virtual hint match physical tag mismatch case cache entry matching hint must evicted cache accesses cache fill address one hint match since virtual hints fewer bits virtual tags distinguishing one another virtually hinted cache suffers conflict misses virtually tagged cache perhaps ultimate reduction virtual hints found pentium 4 willamette northwood cores processors virtual hint effectively two bits cache four-way set associative effectively hardware maintains simple permutation virtual address cache index content-addressable memory cam necessary select right one four ways fetched large physically indexed caches usually secondary caches run problem operating system rather application controls pages collide one another cache differences page allocation one program run next lead differences cache collision patterns lead large differences program performance differences make difficult get consistent repeatable timing benchmark run understand problem consider cpu 1 mib physically indexed direct-mapped level-2 cache 4 kib virtual memory pages sequential physical pages map sequential locations cache 256 pages pattern wraps around label physical page color 0โ255 denote cache go locations within physical pages different colors conflict cache programmers attempting make maximum use cache may arrange programs access patterns 1 mib data need cached given time thus avoiding capacity misses also ensure access patterns conflict misses one way think problem divide virtual pages program uses assign virtual colors way physical colors assigned physical pages programmers arrange access patterns code two pages virtual color use time wide literature optimizations e.g loop nest optimization largely coming high performance computing hpc community snag pages use given moment may different virtual colors may physical colors fact operating system assigns physical pages virtual pages randomly uniformly extremely likely pages physical color locations pages collide cache birthday paradox solution operating system attempt assign different physical color pages different virtual colors technique called page coloring although actual mapping virtual physical color irrelevant system performance odd mappings difficult keep track little benefit approaches page coloring simply try keep physical virtual page colors operating system guarantee physical page maps one virtual color virtual aliases processor use virtually indexed caches need extra virtual alias probes miss handling alternatively os flush page cache whenever changes one virtual color another mentioned approach used early sparc rs/6000 designs modern processors multiple interacting on-chip caches operation particular cache completely specified cache size cache block size number blocks set cache set replacement policy cache write policy write-through write-back cache blocks particular cache size associativity typically lower-level caches called level 1 cache smaller number blocks smaller block size fewer blocks set short access times higher-level caches i.e level 2 progressively larger numbers blocks larger block size blocks set relatively longer access times still much faster main memory cache entry replacement policy determined cache algorithm selected implemented processor designers cases multiple algorithms provided different kinds work loads pipelined cpus access memory multiple points pipeline instruction fetch virtual-to-physical address translation data fetch see classic risc pipeline natural design use different physical caches points one physical resource scheduled service two points pipeline thus pipeline naturally ends least three separate caches instruction tlb data specialized particular role victim cache cache used hold blocks evicted cpu cache upon replacement victim cache lies main cache refill path holds blocks data evicted main cache victim cache usually fully associative intended reduce number conflict misses many commonly used programs require associative mapping accesses fact small fraction memory accesses program require high associativity victim cache exploits property providing high associativity accesses introduced norman jouppi dec 1990 intel crystalwell variant haswell processors equipped intel iris pro gt3e embedded graphics 128 mb edram introduced on-package level 4 cache serves victim cache processors level 3 cache skylake processors level 4 cache longer works victim cache one extreme examples cache specialization trace cache also known execution trace cache found intel pentium 4 microprocessors trace cache mechanism increasing instruction fetch bandwidth decreasing power consumption case pentium 4 storing traces instructions already fetched decoded trace cache stores instructions either decoded retired generally instructions added trace caches groups representing either individual basic blocks dynamic instruction traces pentium 4 trace cache stores micro-operations resulting decoding x86 instructions providing also functionality micro-operation cache next time instruction needed decoded micro-ops write coalescing cache special cache part l2 cache amd bulldozer microarchitecture stores l1d caches module go wcc buffered coalesced wcc task reducing number writes l2 cache micro-operation cache ฮผop cache uop cache uc specialized cache stores micro-operations decoded instructions received directly instruction decoders instruction cache instruction needs decoded ฮผop cache checked decoded form re-used cached available instruction decoded cached one early works describing ฮผop cache alternative frontend intel p6 processor family 2001 paper micro-operation cache power aware frontend variable instruction length isa later intel included ฮผop caches sandy bridge processors successive microarchitectures like ivy bridge haswell amd implemented ฮผop cache zen microarchitecture fetching complete pre-decoded instructions eliminates need repeatedly decode variable length complex instructions simpler fixed-length micro-operations simplifies process predicting fetching rotating aligning fetched instructions ฮผop cache effectively offloads fetch decode hardware thus decreasing power consumption improving frontend supply decoded micro-operations ฮผop cache also increases performance consistently delivering decoded micro-operations backend eliminating various bottlenecks cpu fetch decode logic ฮผop cache many similarities trace cache although ฮผop cache much simpler thus providing better power efficiency makes better suited implementations battery-powered devices main disadvantage trace cache leading power inefficiency hardware complexity required heuristic deciding caching reusing dynamically created instruction traces branch target cache branch target instruction cache name used arm microprocessors specialized cache holds first instructions destination taken branch used low-powered processors need normal instruction cache memory system capable delivering instructions fast enough satisfy cpu without one however applies consecutive instructions sequence still takes several cycles latency restart instruction fetch new address causing cycles pipeline bubble control transfer branch target cache provides instructions cycles avoiding delay taken branches allows full-speed operation much smaller cache traditional full-time instruction cache smart cache level 2 level 3 caching method multiple execution cores developed intel smart cache shares actual cache memory cores multi-core processor comparison dedicated per-core cache overall cache miss rate decreases cores need equal parts cache space consequently single core use full level 2 level 3 cache cores inactive furthermore shared cache makes faster share memory among different execution cores another issue fundamental tradeoff cache latency hit rate larger caches better hit rates longer latency address tradeoff many computers use multiple levels cache small fast caches backed larger slower caches multi-level caches generally operate checking fastest level 1 l1 cache first hits processor proceeds high speed smaller cache misses next fastest cache level 2 l2 checked accessing external memory latency difference main memory fastest cache become larger processors begun utilize many three levels on-chip cache price-sensitive designs used pull entire cache hierarchy on-chip 2010s highest-performance designs returned large off-chip caches often implemented edram mounted multi-chip module fourth cache level benefits l3 l4 caches depend application access patterns examples products incorporating l3 l4 caches include following finally end memory hierarchy cpu register file considered smallest fastest cache system special characteristic scheduled softwareโtypically compiler allocates registers hold values retrieved main memory example loop nest optimization however register renaming compiler register assignments reallocated dynamically hardware runtime register bank allowing cpu break false data dependencies thus easing pipeline hazards register files sometimes also hierarchy cray-1 circa 1976 eight address eight scalar data registers generally usable also set 64 address b 64 scalar data registers took longer access faster main memory b registers provided cray-1 data cache cray-1 however instruction cache considering chip multiple cores question whether caches shared local core implementing shared cache inevitably introduces wiring complexity one cache per chip rather core greatly reduces amount space needed thus one include larger cache typically sharing l1 cache undesirable resulting increase latency would make core run considerably slower single-core chip however highest-level cache last one called accessing memory global cache desirable several reasons allowing single core use whole cache reducing data redundancy making possible different processes threads share cached data reducing complexity utilized cache coherency protocols example eight-core chip three levels may include l1 cache core one intermediate l2 cache pair cores one l3 cache shared cores shared highest-level cache called accessing memory usually referred last level cache llc additional techniques used increasing level parallelism llc shared multiple cores including slicing multiple pieces addressing certain ranges memory addresses accessed independently separate cache structure instructions data cached separately meaning cache line used cache either instructions data various benefits demonstrated separate data instruction translation lookaside buffers unified structure constraint present cache lines used cache instructions data multi-level caches introduce new design decisions instance processors data l1 cache must also somewhere l2 cache caches called strictly inclusive processors like amd athlon exclusive caches data guaranteed one l1 l2 caches never still processors like intel pentium ii iii 4 require data l1 cache also reside l2 cache although may often universally accepted name intermediate policy two common names non-exclusive partially-inclusive advantage exclusive caches store data advantage larger exclusive l1 cache comparable l2 cache diminishes l2 cache many times larger l1 cache l1 misses l2 hits access hitting cache line l2 exchanged line l1 exchange quite bit work copying line l2 l1 inclusive cache one advantage strictly inclusive caches external devices processors multiprocessor system wish remove cache line processor need processor check l2 cache cache hierarchies enforce inclusion l1 cache must checked well drawback correlation associativities l1 l2 caches l2 cache least many ways l1 caches together effective associativity l1 caches restricted another disadvantage inclusive cache whenever eviction l2 cache possibly corresponding lines l1 also get evicted order maintain inclusiveness quite bit work would result higher l1 miss rate another advantage inclusive caches larger cache use larger cache lines reduces size secondary cache tags exclusive caches require caches size cache lines cache lines swapped l1 miss l2 hit secondary cache order magnitude larger primary cache data order magnitude larger cache tags tag area saved comparable incremental area needed store l1 cache data l2 illustrate specialization multi-level caching cache hierarchy k8 core amd athlon 64 cpu k8 four specialized caches instruction cache instruction tlb data tlb data cache caches specialized k8 also multiple-level caches second-level instruction data tlbs store ptes mapping 4 kb instruction data caches various tlbs fill large unified l2 cache cache exclusive l1 instruction data caches means 8-byte line one l1 instruction cache l1 data cache l2 cache however possible line data cache pte also one tlbsโthe operating system responsible keeping tlbs coherent flushing portions page tables memory updated k8 also caches information never stored memoryโprediction information caches shown diagram usual class cpu k8 fairly complex branch prediction tables help predict whether branches taken tables predict targets branches jumps information associated instructions level 1 instruction cache unified secondary cache k8 uses interesting trick store prediction information instructions secondary cache lines secondary cache protected accidental data corruption e.g alpha particle strike either ecc parity depending whether lines evicted data instruction primary caches since parity code takes fewer bits ecc code lines instruction cache spare bits bits used cache branch prediction information associated instructions net result branch predictor larger effective history table better accuracy processors kinds predictors e.g store-to-load bypass predictor dec alpha 21264 various specialized predictors likely flourish future processors predictors caches store information costly compute terminology used discussing predictors caches one speaks hit branch predictor predictors generally thought part cache hierarchy k8 keeps instruction data caches coherent hardware means store instruction closely following store instruction change following instruction processors like alpha mips family relied software keep instruction cache coherent stores guaranteed show instruction stream program calls operating system facility ensure coherency computer engineering tag ram used specify possible memory locations currently stored cpu cache simple direct-mapped design fast sram used higher associative caches usually employ content-addressable memory cache reads common cpu operation takes single cycle program execution time tends sensitive latency level-1 data cache hit great deal design effort often power silicon area expended making caches fast possible simplest cache virtually indexed direct-mapped cache virtual address calculated adder relevant portion address extracted used index sram returns loaded data data byte aligned byte shifter bypassed next operation need tag checking inner loop fact tags need even read later pipeline load instruction retired tag loaded data must read checked virtual address make sure cache hit miss cache updated requested cache line pipeline restarted associative cache complicated form tag must read determine entry cache select n-way set-associative level-1 cache usually reads n possible tags n data parallel chooses data associated matching tag level-2 caches sometimes save power reading tags first one data element read data sram adjacent diagram intended clarify manner various fields address used address bit 31 significant bit 0 least significant diagram shows srams indexing multiplexing 4 kb 2-way set-associative virtually indexed virtually tagged cache 64 byte b lines 32-bit read width 32-bit virtual address cache 4 kb 64 b lines 64 lines cache read two time tag sram 32 rows pair 21 bit tags although function virtual address bits 31 6 could used index tag data srams simplest use least significant bits similarly cache 4 kb 4 b read path reads two ways access data sram 512 rows 8 bytes wide modern cache might 16 kb 4-way set-associative virtually indexed virtually hinted physically tagged 32 b lines 32-bit read width 36-bit physical addresses read path recurrence cache looks similar path instead tags vhints read matched subset virtual address later pipeline virtual address translated physical address tlb physical tag read one vhint supplies way cache read finally physical address compared physical tag determine hit occurred sparc designs improved speed l1 caches gate delays collapsing virtual address adder sram decoders see sum addressed decoder early history cache technology closely tied invention use virtual memory scarcity cost semi-conductor memories early mainframe computers 1960s used complex hierarchy physical memory mapped onto flat virtual memory space used programs memory technologies would span semi-conductor magnetic core drum disc virtual memory seen used programs would flat caching would used fetch data instructions fastest memory ahead processor access extensive studies done optimize cache sizes optimal values found depend greatly programming language used algol needing smallest fortran cobol needing largest cache sizes early days microcomputer technology memory access slightly slower register access since 1980s performance gap processor memory growing microprocessors advanced much faster memory especially terms operating frequency memory became performance bottleneck technically possible main memory fast cpu economically viable path taken use plenty low-speed memory also introduce small high-speed cache memory alleviate performance gap provided order magnitude capacityโfor priceโwith slightly reduced combined performance first documented uses tlb ge 645 ibm 360/67 used associative memory tlb first documented use data cache ibm system/360 model 85 68010 released 1982 loop mode considered tiny special-case instruction cache accelerates loops consist two instructions 68020 released 1984 replaced typical instruction cache 256 bytes first 68k series processor feature true on-chip cache memory 68030 released 1987 basically 68020 core additional 256-byte data cache process shrink added burst mode caches 68040 released 1990 split instruction data caches four kilobytes 68060 released 1994 following 8 kb data cache four-way associative 8 kb instruction cache four-way associative 96-byte fifo instruction buffer 256-entry branch cache 64-entry address translation cache mmu buffer four-way associative x86 microprocessors reached clock rates 20 mhz 386 small amounts fast cache memory began featured systems improve performance dram used main memory significant latency 120 ns well refresh cycles cache constructed expensive significantly faster sram memory cells time latencies around 10 ns 25 ns early caches external processor typically located motherboard form eight nine dip devices placed sockets enable cache optional extra upgrade feature versions intel 386 processor could support 16 256 kb external cache 486 processor 8 kb cache integrated directly cpu die cache termed level 1 l1 cache differentiate slower on-motherboard level 2 l2 cache on-motherboard caches much larger common size 256 kb popularity on-motherboard cache continued pentium mmx era made obsolete introduction sdram growing disparity bus clock rates cpu clock rates caused on-motherboard cache slightly faster main memory next development cache implementation x86 microprocessors began pentium pro brought secondary cache onto package microprocessor clocked frequency microprocessor on-motherboard caches enjoyed prolonged popularity thanks amd k6-2 amd k6-iii processors still used socket 7 previously used intel on-motherboard caches k6-iii included 256 kb on-die l2 cache took advantage on-board cache third level cache named l3 motherboards 2 mb on-board cache produced socket 7 became obsolete on-motherboard cache disappeared x86 systems three-level caches used first introduction multiple processor cores l3 cache added cpu die became common total cache sizes increasingly larger newer processor generations recently 2011 uncommon find level 3 cache sizes tens megabytes intel introduced level 4 on-package cache haswell microarchitecture crystalwell haswell cpus equipped gt3e variant intel integrated iris pro graphics effectively feature 128 mb embedded dram edram package l4 cache shared dynamically on-die gpu cpu serves victim cache cpu l3 cache early cache designs focused entirely direct cost cache ram average execution speed recent cache designs also consider energy efficiency fault tolerance goals researchers also explored use emerging memory technologies edram embedded dram nvram non-volatile ram designing caches several tools available computer architects help explore tradeoffs cache cycle time energy area tools include open-source cacti cache simulator open-source simplescalar instruction set simulator modeling 2d 3d sram edram stt-ram reram pcm caches done using destiny tool multi-ported cache cache serve one request time accessing traditional cache normally use single memory address whereas multi-ported cache may request n addresses time n number ports connected processor cache benefit pipelined processor may access memory different phases pipeline another benefit allows concept super-scalar processors different cache levels
|
Computer architecture
|
snaplogic snaplogic commercial software company provides integration platform service ipaas tools connecting cloud data sources saas applications on-premises business software applications headquartered san mateo ca snaplogic founded 2006 snaplogic headed ex-ceo co-founder informatica gaurav dhillon venture backed andreessen horowitz ignition partners floodgate fund brian mcclendon naval ravikant 2017 company raised 136.3 million december 10 2015 snaplogic announced 37.5 million funding round led microsoft silver lake waterman along existing investors andreessen horowitz ignition partners triangle peak partners made total investment raised 96.3 million snaplogic time announcement snaplogic elastic integration platform consists integration cloud prebuilt connectors called snaps snaplex data processing cloud behind firewall company products referred targeting internet things marketplace connecting data applications devices integration cloud approaches big data integration following tools snaplex self-upgrading elastic execution grid streams data applications databases files social big data sources snaplex run cloud behind firewall hadoop snaps modular collections integration components built specific application data source available analytics big data sources identity management social media online storage erp databases technologies xml json oauth soap rest snap patterns introduced march 2014 help connecting cloud services like amazon redshift salesforce.com workday servicenow on-premises applications databases files company winter 2015 release focused adding tighter security added support hadoop big data integration product line
|
Distributed computing architecture
|
autovivification perl programming language autovivification automatic creation new arrays hashes required every time undefined value dereferenced perl autovivification allows programmer refer structured variable arbitrary sub-elements structured variable without expressly declaring existence variable complete structure beforehand contrast programming languages either 1 require programmer expressly declare entire variable structure using referring part 2 require programmer declare part variable structure referring part 3 create assignment part variable referring assigning composing expression refers part perl autovivification contrasted languages python php ruby many c style languages dereferencing null undefined values generally permitted compared html standard named access window object results corresponding globally scoped variables automatically accessible browser-based javascript important remember autovivification happens undefined value dereferenced assignment necessary debugger session illustrates autovivification hash examining debugger session illustrates autovivification hash assigning inner hash hashes several layers deep created automatically without declarations autovivification prevent excessive typing perl support autovivification structure would created follows perl 5.6.1 newer support autovivification file directory handles calling codice_1 undefined variable set filehandle according perl561delta largely eliminates need typeglobs opening filehandles must passed around following example c++ associative containers like codice_2 use codice_3 get value associated key nothing associated key construct another example counting occurrences string similar trick achieved codice_4 method returns iterator element associated key even already exists python built-in codice_5 class subclassed implement autovivificious dictionaries simply overriding codice_6 method added class python v2.5 ways implementing behavior following one simplest instances class print like normal python dictionary objects ruby hashes take block specifying object returned non-existing indexes used implement autovivificious maps java map method computeifabsent used emulate autovivificous maps php arrays natively autovivificious however applies assignment array access es6 introduces new proxy class used implement autovivification features javascript reduced single line code c using indexers c 4.0 dynamics dynamicobject used implementing different syntaxes also
|
Programming language topics
|
table database table collection related data held table format within database consists columns rows relational databases flat file databases table set data elements values using model vertical columns identifiable name horizontal rows cell unit row column intersect table specified number columns number rows row identified one values appearing particular column subset specific choice columns uniquely identify rows called primary key table another term relation although difference table usually multiset bag rows relation set allow duplicates besides actual data rows tables generally associated metadata constraints table values within particular columns data table physically stored database views also function relational tables data calculated query time external tables informix oracle example also thought views terms relational model databases table considered convenient representation relation two strictly equivalent instance sql table potentially contain duplicate rows whereas true relation contain duplicate rows call tuples similarly representation table implies particular ordering rows columns whereas relation explicitly unordered however database system guarantee ordering rows unless codice_1 clause specified codice_2 statement queries table equally valid representation relation n -dimensional chart n number attributes table columns example relation two attributes three values represented table two columns three rows two-dimensional graph three points table graph representations equivalent ordering rows significant table duplicate rows non-relational systems hierarchical databases distant counterpart table structured file representing rows table row file column row structure implies row repeating information generally child data segments data stored sequence physical records unlike spreadsheet datatype column ordinarily defined schema describing table sql systems sqlite less strict column datatype definitions
|
Databases
|
hue software hue open-source sql cloud editor licensed apache v2 license hue open source sql cloud editor browsing querying visualizing data goal make self service data querying widespread organizations hue team works provides releases website hue also present major hadoop distributions cdh hdp mapr aws emr demo vms
|
Distributed computing architecture
|
nim programming language nim formerly named nimrod imperative general-purpose multi-paradigm statically typed systems compiled programming language designed developed andreas rumpf designed efficient expressive elegant supporting metaprogramming functional message passing procedural object-oriented programming styles providing several features compile time code generation algebraic data types foreign function interface ffi c c++ compiling c c++ objective-c javascript nim statically typed supports compile-time metaprogramming features syntactic macros term rewriting macros term rewriting macros enable library implementations common data structures bignums matrices implemented efficiently builtin language facilities iterators supported used first class entities functions allowing use functional programming methods object-oriented programming supported inheritance multiple dispatch functions generic also overloaded generics enhanced support type classes operator overloading also supported nim includes tunable automatic garbage collection based deferred reference counting cycle detection turned altogether 2014 andrew binstock editor-in-chief dr. dobb journal said nimrod former name ... presents original design straddles pascal python compiles c code javascript today nim compiles c c++ javascript objective-c goal nim fast c expressive python extensive lisp nim initial development started 2006 andreas rumpf project made public 2008 first version nim compiler written pascal using free pascal compiler 2008 version compiler written nim released compiler free open-source software developed community volunteers working andreas rumpf language officially renamed nimrod nim release version 0.10.2 december 2014 syntax nim highly resembles python code blocks nesting statements identified use white-space according offside-rule many keywords identical python equivalents mostly english keywords programming languages use punctuation even though nim supports indentation based syntax like python introduced flexibility whereby one could break statement comma binary operator next line nim also supports user-defined operators nim almost fully style-insensitive two identifiers considered equal differ capitalization underscores long first characters identical details influenced also nim supports uniform function call syntax ufcs identifier equality nim compiler emits optimized c code defers compiling external compiler leverage optimizing portability abilities many compilers supported including clang gnu compiler collection gcc compiler also emit c++ objective-c javascript code allow easy interfacing application programming interfaces apis written languages allows writing applications ios android nim compiler self-hosting meaning written nim language nimble standard package manager used nim package nim modules initially developed dominik picheta also core nim developer newer releases nim come nimble included nimble packages defined codice_1 files contain information package version author license description dependencies files support limited subset nim syntax called nimscript main limitation access ffi scripts allow changing test procedure custom tasks written list packages stored json file freely accessible nim-lang/packages repository github json file provides nimble mapping names packages git mercurial repository urls nimble comes nim compiler possible test nimble environment running codice_2 command reveal version number compilation date time git hash nimble nimble utilizes git must available nimble function well nimble command-line used interface installing removing uninstalling upgrading/patching module packages c2nim transcompiler/transpiler helps generate new bindings translating ansi c code nim code output human-readable nim code meant tweaked hand translation process choosenim developed dominik picheta tool enables developer multiple versions nim compile his/her machine choosenim installs nim official downloads sources enabling easy switching stable development compilers nimfix tool helps convert old-style nimrod code nim code nimfix currently beta-quality pas2nim tool translate object pascal wrappers nim code used translate original pascal sources nim compiler maps easily nim supported free pascal delphi-style classes features unsupported time development maintenance mostly stalled py2nim tool used transpiling python code idiomatic nim code development active plans extend amount python code fully translated nim nim program use library used c c++ program language bindings exist many libraries including gtk+ sdl2 cairo opengl winapi zlib libzip openssl curl nim works postgresql mysql sqlite databases nim interface lua python interpreter following code examples valid nim 0.19.0. subsequent releases nim 1.0 release syntax semantics may change later versions hello world program nim echo hello world echo hello world another version coding hello world ... stdout.write hello world simple demonstration showing many nim features proc reverse string string let str1 reverse echo reversed reverse str1 one exotic features implicit codice_3 variable every procedure nim non-void return type implicit result variable represents value returned loop see invocation codice_4 iterator iterator omitted compiler attempt use codice_5 iterator one defined type specified run overridden oloop stropping method mark explicitly letter sequence special purpose stropping used modern languages instead keywords reserved words used identifiers variables functions stropping allows letter sequence used keyword identifier simplifies parsing example allowing variable named codice_6 without clashing keyword codice_6 nim achieved via backticks allowing reserved word used identifier var type int example metaprogramming nim using template facilities template gentype name fieldname untyped fieldtype typedesc gentype test foo int var x test foo 4566 echo x.foo 4566 codice_8 invoked compile-time codice_9 type created nim ffi used call functions written programming languages compile means libraries written c c++ objective-c javascript used nim source code one aware javascript c c++ objective-c libraries combined program compatible javascript c++ objective-c based compatible c javascript incompatible dynamic client-side web-based language following program demonstrates ease extant c code used directly nim printf d\n foo 5 code codice_10 function imported nim used project bug tracker wiki hosted github forum presentation nim given o'reilly open source convention oscon 2015
|
Programming language topics
|
ahn cheol-soo ahn cheol-soo born 26 february 1962 south korean politician medical doctor businessperson software entrepreneur two-time former presidential election candidate 2012 2017 ahn currently bareunmirae party candidate seoul mayorship ran independent candidate presidential election 2012 withdrew month election took place support moon jae-in ran 2017 people party nominee founding co-leader party leader people party party bareun party merged bareunmirae party february 2018 prior politics ahn founded ahnlab inc. antivirus software company 1995 chairman board chief learning officer ahnlab september 2012 remains company largest stakeholder prior entering politics ahn served dean graduate school convergence science technology seoul national university september 2012 ahn born 26 february 1962 miryang south korea father military service subsequently moved family busan grew ahn academic child number academic hobbies reading received doctor medicine md master science ms doctor philosophy phd degrees physiology seoul national university 1980 1991 became youngest chief professors dankook university medical college 27 years age marking first career medical doctor ahn met wife whilst university whilst working graduate student pursuing md ahn began gain interest computer software hobby particular antivirus software ahn soon began working antivirus software confronted virus mass-infecting computers korea ahn soon infected virus reverse engineered virus attempt erase disk drive successful program wrote help get rid virus eventually called vaccine ahn distributed free finishing military service medical officer south korean navy leaving behind career medical profession cheol-soo went establish venture company ahnlab inc march 1995 advised software company official ahn previously attempted distribute v3 via samsung brand though samsung rejected ahn offer ahn knowing run business first struggled first several years whilst managing company ahn also attempting get master degree engineering university pennsylvania graduated 1997 ahn eventually received 10 million offer us software giant mcafee ahn met john mcafee personally mcafee struggling expand south korea due ahnlab inc wanted purchase company attempt monopolize anti-virus software market south korea ahn rejected offer despite ahnlab inc struggling selling company would lead widespread redundancies 1999 company began run surplus cih virus became widespread korea people needed buy v3 protect end 1999 ahnlab inc became second biggest computer security company south korea company later became largest computer security company south korea included annual lists korea admired companies korea management association consulting 2004 2008 resigned ceo 2005 served chairman board 2012 ahn revealed john mcafee suggested would acquire ahnlab 10,000,000 rejected offer mentioned patriotic reasons decision saying selling ahnlab might allow foreign firm dominate korean market ahn became outside director posco 2005 2010 2011 chairman company ahn awarded executive master business administration emba degree wharton school san francisco campus 2008 became professor kaist 2008 later beginning 2011 became dean graduate school convergence science technology seoul national university since 2006 ahn offered places main political parties constantly denied chance run independent due opposing factions early september 2011 speculation spread ahn would enter politics competing 26 october seoul mayoral by-election democratic party liberty korea party attempted recruit ahn mayoral by-election though failed due ahn feeling like many voters become disenfranchised main two choices ahn eventually made announcement denouncing opposition ruling party saying sure candidacy deciding watch polls making choice though shared sentiment felt like 'd take lot work help seoul saying ten years work would needed help city analysts stated positioned independent ahn would attract degree support disaffected mainstream political parties wake corruption allegations continuing policy failures ahn polling higher potential candidates 35 second place coming 17 approval rating subsequently polled afterwards reaching 50 ahn eventually n't run despite positive poll ratings instead endorsing park won-soon went win by-election park win attributed ahn endorsement due centrist voters moving park side endorsement alluded standing presidential candidate 2012 book thoughts ahn cheol-soo 19 september 2012 3 p.m. korea standard time ahn held press conference announced intention run 2012 presidential election announcement came months speculation whether ahn going run presidency south korean presidential election held 19 december 2012 address lasted around 20 minutes ahn spent considerable amount time explaining came decision run president republic korea quoting people met exploring candidacy expressed desire new politics ahn one point showed polling stronger moon jae-in polls showing could win park geun-hye candidate would go win election 23 november 2012 8:20 p.m. kst ahn announced would drop race endorsing moon jae-in democratic united party presidential candidate 11 march 2013 ahn announced would run seat national assembly south korea independent candidate by-election district seoul nowon c. election 24 april entering first elected office may 2013 launched new think tank named policy network tomorrow entered assembly ahn began explore creation new party provisionally named new political vision party basis public surveys 26 march 2014 however party process set ahn merged faction liberal democratic party form new politics alliance democracy npad becoming co-chairman new party alongside kim han-gil ahn kim resigned position three months later july following new party disappointing performance by-elections year seen liberals lose seat jeolla conservatives first time 26 years ahn remained npad came increasing conflict moon jae-in taken sole leadership party resignation pro-roh faction moon represented december 2015 ahn issued ultimatum moon demanding convention held beginning 2016 elect new party leader moon rejected demand ahn left npad along range lawmakers opposed moon including kim han-gil announcing would form new party subsequently joined forces chun jung-bae left party earlier year form people party january 2016 moon resigned leader ahn defection describing experience series difficult days without single one respite ahn positioned new people party anti-establishment centrist force attracting support political wings labeled remaining npad anachronistic progressives accused contemporary korean politicians lacking policies beyond short-term gimmicks lead-up april 13 parliamentary election came conflict co-leader chun members party kim chong-in interim leader democratic party npad successor called two parties form electoral alliance kim han-gil ahn co-leader chun supported plan ahn rejected prospect alliance former party proposal ultimately scotched kim han-gil withdrawing upcoming election protest event people party performed better anticipated coming second party-list voting winning 38 seats overall including 23 28 districts liberal stronghold jeolla people party held balance power new assembly establishing three-party system ahn credited victory seen giving position kingmaker support contesting presidential elections following year following election ahn rejected continued calls regroup minjoo party stating would inappropriate speak politically realigning point time added people party would mere tie-breaking third party ... new opinion leader parliamentary affairs ahn widely known likely contender 2017 south korean presidential election selected people party nominee defeating sohn hak-kyu park joo-sun despite rapid increase opinion polling briefly bypassed moon jae-in ahn floundered tv debates led loss finishing third field five total candidates underperformance presidential campaign party scandal found people party members fabricating evidence smear moon jae-in campaign led ahn declare july 2017 apologize take step back politics self-reflection returned month later run later win party chairmanship head people party ahn strong advocate merging center-right bareun party two leaders respective parties ahn former presidential contender yoo seung-min pushed forward merger completed february 2018 although yoo retained leadership position within new party ahn stepped leadership role march 2018 took role leading party talent recruiting committee formal position speculated signal preparation run seoul mayorship later year ahn stated considers franklin d. roosevelt role model referred bernie sanders korea supports increased capital gains tax higher public welfare spending cautious approach free trade agreements ahn also made appeals conservatives however associated people party reformative currents korean conservatism september 2012 ahn visited graves syngman rhee park chung-hee kim dae-jung park rhee often praised korean conservatives kim liberals ahn stated time would hypocritical paint half people enemies time call 'unity ahn considered palatable conservative voters part due business background ahn among first opposed american deployment terminal high altitude area defense system commonly referred thaad alongside moon jae-in however changed stance suggesting irresponsible future president reverse agreement already made united states korea ahn stated opposes legalization same-sex marriage although detailed article broadcasting network sbs website said same-sex marriage needs achieved social discussion december 2011 ahn expressed willingness donate half shares ahnlab education children low-income families owns 37.1 percent ahnlab shares 9 december 2011 value shares donated 250 billion 218 million september 2012 ahn made public apology reports surfaced wife evaded taxes under-pricing 2001 apartment bought worth โฉ450 million โฉ250 million thus reducing acquisition registration taxes โฉ10 million however statement korea taxpayers association claimed contract accordance trade customs thus unlawful due flaws local tax law 1996 2005 1988 married kim mi-kyung currently professor seoul national university college medicine ahn daughter kim
|
Computer security
|
vanish computer science vanish project give users control lifetime personal data stored web led roxana geambasu university washington project proposes allow user enter information send across internet thereby relinquishing control however user able include expiration date information longer usable anyone may copy even creator vanish approach found vulnerable sybil attack thus insecure team called unvanish university texas university michigan princeton vanish acts automating encryption information entered user encryption key unknown user along actual information user enters also enters metadata concerning long information remain available system encrypts information store either encryption key original information instead breaks decryption key smaller components disseminated across distributed hash tables dhts via internet dhts refresh information within nodes set schedule unless told persist information time-delay entered user metadata controls long dhts allow information persist time period dhts reuse nodes making information decryption stored irretrievable long decryption key may reassembled dhts information retrievable however time initially entered user lapsed information recoverable user never informed decryption key vanish currently exists firefox plug-in allows user enter text either standard gmail email facebook message choose send message via vanish message encrypted sent via normal networking pathways cloud recipient recipient must firefox plug-in decrypt message plugin accesses bittorrent dhts 8-hour lifespans means user may select expiration date message increments 8 hours expiration user-defined time span information dht overwritten thereby eliminating key user recipient may copies original encrypted message key used turn back plain text gone although particular instance data become inaccessible important note information always saved means expiration copied even via screen shots published
|
Computer security
|
citic telecom cpc citic telecom international cpc limited formerly known psinet hk cpcnet wholly owned subsidiary citic telecom international holdings limited technological company involved managed cloud computing ip networking information security data center services company owns operates computing security networking facilities communications linkages in-country local sales offices 2016 citic telecom cpc extended global reach acquiring linx telecommunication b.v. linx telecommunications became one first asian ict service providers points-of-presence along โ one belt one road โ infrastructure framework including amsterdam frankfurt warsaw vilnius lithuania stockholm helsinki finland saint petersburg russia moscow tallinn estonia riga latvia kiev ukraine budapest hungary almaty kazakhstan tibilisi georgia baku azerbaijan locations citic pacific acquired psinet hk 2001 following year psinet hk renamed cpcnet subsequently renamed โ citic telecom cpc โ six 6 points-of-presence beijing shanghai guangzhou shenzhen hong kong taiwan citic telecom cpc began providing mpls vpn services hong kong taiwan companies business operations mainland china 2006 citic telecom cpc launched information security services year citic telecom cpc expanded presence greater china south-east asia 2010 citic telecom international holdings limited acquired china enterprise ict solutions limited citic telecom cpc 2011 cloud computing solution launched 2011 cpcnet renamed citic telecom international cpc limited citic telecom cpc became one first vmware vcloud ยฎ powered service providers greater china 2016 saw citic telecom cpc commence acquired acquiring linx telecommunications linx telecommunication b.v. renamed merged company citic telecom cpc europe acquisition extended citic telecom cpc global infrastructure points-of-presence central asia central eastern europe markets including regions encompassed china โ one belt one road โ economic cooperation initiative 2017 citic telecom cpc also became first iaas provider receive new cloud-centric iso27017 certification hong kong citic telecom cpc thus became first asian managed services provider points-of-presence across multitude countries along new โ digital silk road โ including amsterdam frankfurt warsaw vilnius lithuania stockholm helsinki finland saint petersburg russia moscow tallinn estonia riga latvia kiev ukraine budapest hungary almaty kazakhstan tibilisi georgia baku azerbaijan locations acquisition expanded citic telecom cpc global footprint asia pacific north america western europe encompass central asia eastern europe parent company citic telecom international holdings limited hkse 1883 ict service provider asia pacific subsidiary company china enterprise ict solutions limited โ china entercom โ โ cec โ founded 2000 information communications technology ict service provider china
|
Distributed computing architecture
|
voice activity detection voice activity detection vad also known speech activity detection speech detection technique used speech processing presence absence human speech detected main uses vad speech coding speech recognition facilitate speech processing also used deactivate processes non-speech section audio session avoid unnecessary coding/transmission silence packets voice internet protocol applications saving computation network bandwidth vad important enabling technology variety speech-based applications therefore various vad algorithms developed provide varying features compromises latency sensitivity accuracy computational cost vad algorithms also provide analysis example whether speech voiced unvoiced sustained voice activity detection usually language independent first investigated use time-assignment speech interpolation tasi systems typical design vad algorithm follows may feedback sequence vad decision used improve noise estimate noise reduction stage adaptively vary threshold feedback operations improve vad performance non-stationary noise i.e noise varies lot representative set recently published vad methods formulates decision rule frame frame basis using instantaneous measures divergence distance speech noise different measures used vad methods include spectral slope correlation coefficients log likelihood ratio cepstral weighted cepstral modified distance measures independently choice vad algorithm must compromise voice detected noise noise detected voice false positive false negative vad operating mobile phone must able detect speech presence range diverse types acoustic background noise difficult detection conditions often preferable vad fail-safe indicating speech detected decision doubt lower chance losing speech segments biggest difficulty detection speech environment low signal-to-noise ratios snrs encountered may impossible distinguish speech noise using simple level detection techniques parts speech utterance buried noise wide range applications digital mobile radio digital simultaneous voice data dsvd speech storage desirable provide discontinuous transmission speech-coding parameters advantages include lower average power consumption mobile handsets higher average bit rate simultaneous services like data transmission higher capacity storage chips however improvement depends mainly percentage pauses speech reliability vad used detect intervals one hand advantageous low percentage speech activity hand clipping loss milliseconds active speech minimized preserve quality crucial problem vad algorithm heavy noise conditions one controversial application vad conjunction predictive dialers used telemarketing firms order maximize agent productivity telemarketing firms set predictive dialers call numbers agents available knowing calls end either โ ring โ answer โ answering machines person answers typically speak briefly โ hello โ โ good evening โ etc brief period silence answering machine messages usually contain 3โ15 seconds continuous speech setting vad parameters correctly dialers determine whether person machine answered call person transfer call available agent detects answering machine dialer hangs often system correctly detects person answering call agent available leaves called party frustratedly repeating โ hello hello โ phone combined volume agents get created impetus develop โ call โ lists across us evaluate vad output using test recordings compared โ ideal โ vad โ created hand-annotating presence/absence voice recordings performance vad commonly evaluated basis following four parameters although method described provides useful objective information concerning performance vad approximate measure subjective effect example effects speech signal clipping times hidden presence background noise depending model chosen comfort noise synthesis clipping measured objective tests reality audible therefore important carry subjective tests vads main aim ensure clipping perceived acceptable kind test requires certain number listeners judge recordings containing processing results vads tested listeners give marks following features marks obtained listening several speech sequences used calculate average results features listed thus providing global estimate behavior vad tested conclude whereas objective methods useful initial stage evaluate quality vad subjective methods significant however expensive since require participation certain number people days generally used proposal standardized
|
Computational linguistics
|
atscript atscript proposed javascript-based scripting language extending microsoft typescript transcompiling javascript introduced october 2014 ng-europe conference developers google angularjs web development framework language upcoming angular 2.0 would built atscript originally intended run top typescript including features dart october 2014 google announced angular 2.0 would written atscript march 2015 microsoft announced many atscript features would implemented typescript 1.5 release angular 2.0 would built pure typescript name โ atscript โ comes โ โ symbol used annotations many languages
|
Programming language topics
|
finjan finjan holdings finjan publicly traded company nasdaq fnjn centers licensing intellectual property finjan claims patented technology used enterprise web security solutions finjan filed large number lawsuits leading software security companies asserting patents including cisco palo alto networks symantec blue coat systems sophos trend micro eset bitdefender check point qualys rapid7 fortinet others finjan named patent troll original hardware software divisions finjan acquired m86 security 2009 finjan continues hold patents various web security technologies licenses patents trustwave formerly m86 among others finjan commitment innovation security space continues investments culminated recent launch finjan consulting services business cyberisk development mobile applications consumer subsidiary finjan mobile incubation up-and-coming technology startups pioneering new generation security technologies company investment jerusalem venture partners jvp fund vii cyber labs invested alongside companies like cisco technology companies company headquartered east palo alto california finjan founded 1997 shlomo touboul serial entrepreneur founded first company shani computers 1985 sold intel 1994 worked intel starting finjan 1998 touboul decided bring experienced seasoned ceo would able develop grow company quickly left start venture capital fund 2001 company ran financial difficulties touboul asked board directors rejoin company ceo touboul realigned company strategy moving away developing software solutions combined hardware software security appliances additionally company moved channel sales model december 2002 finjan acquired assets alchemedia software developer drm product called clever content several drm patents alchemedia also ties israel founder daniel schreiber israeli though company technically headquartered dallas area 2005 following disagreements board touboul left started new company yoggie security systems october 2007 eric benhamou former ceo chairman 3com appointed chairman finjan also invested company venture capital fund benhamou global ventures november 2009 hardware software divisions finjan sold m86 security global computer security firm based orange california international headquarters london offices worldwide m86 subsequently acquired trustwave still use finjan technology patents licensing agreement finjan appliances sold trustwave secure web gateway june 2013 finjan became publicly traded company capitalized 30m installed new management team began focused program license company landmark intellectual property may 2014 finjan listed nasdaq capital market trading symbol fnjn continue trade today finjan initial shareholders included cisco microsoft bessemer venture partners benchmark capital harbourvest partners israel seed partners november 2008 company secured additional investment 22m brought total capital invested finjan since founding 67 million june 2013 finjan became publicly traded company capitalized 30m installed new management team began focused program license company landmark intellectual property may 2014 finjan listed nasdaq capital market trading symbol fnjn finjan claims invented concept proactive content security behavior-based content analysis technology claim shared others selected technology patents licensed microsoft july 2005 april 2009 finjan intellectual property portfolio included granted pending patents areas behavior-based security digital rights management finjan portfolio includes processes enable networks execute security plans counteract effects polymorphic code designed hide malware
|
Computer security
|
re-order buffer re-order buffer rob used tomasulo algorithm out-of-order instruction execution allows instructions committed in-order normally three stages instructions issue execute write result tomasulo algorithm additional stage commit stage results instructions stored register memory write result stage results put re-order buffer contents buffer used executing instructions depending additional fields every entry buffer additional benefits re-order buffer include precise exceptions easy rollback control target address mispredictions branch jump rob works storing instructions original fetched order rob also accessed side since reservation station tomasulo algorithm additional parameter points instruction rob jump prediction correct nonrecoverable exception encountered instruction stream rob cleared instructions reservation stations re-initialized
|
Computer architecture
|
remote desktop protocol remote desktop protocol rdp proprietary protocol developed microsoft provides user graphical interface connect another computer network connection user employs rdp client software purpose computer must run rdp server software clients exist versions microsoft windows including windows mobile linux unix macos ios android operating systems rdp servers built windows operating systems rdp server unix os x also exists default server listens tcp port 3389 udp port 3389 microsoft currently refers official rdp client software remote desktop connection formerly terminal services client protocol extension itu-t t.128 application sharing protocol every version microsoft windows windows xp onwards includes installed remote desktop connection rdc terminal services client mstsc.exe whose version determined operating system last applied windows service pack terminal services server supported official feature windows nt 4.0 terminal server edition windows 2000 server editions windows xp except windows xp home edition windows server 2003 windows home server windows fundamentals legacy pcs windows vista ultimate enterprise business editions windows server 2008 windows server 2008 r2 windows 7 professional microsoft provides client required connecting newer rdp versions downlevel operating systems since server improvements available downlevel features introduced newer rdp version work downlevel operating systems connecting higher version rdp server older operating systems using rdp server older operating system based itu-t t.128 application sharing protocol draft also known t.share t.120 recommendation series first version rdp named version 4.0 introduced microsoft terminal services part product windows nt 4.0 server terminal server edition terminal services edition nt 4.0 relied citrix multiwin technology previously provided part citrix winframe atop windows nt 3.51 order support multiple users login sessions simultaneously microsoft required citrix license multiwin technology microsoft order allowed continue offering terminal-services product named citrix metaframe atop windows nt 4.0 citrix-provided dlls included windows nt 4.0 terminal services edition still carry citrix copyright rather microsoft copyright later versions windows integrated necessary support directly t.128 application sharing technology acquired microsoft uk software developer data connection limited version introduced windows 2000 server added support number features including printing local printers aimed improve network bandwidth usage version introduced windows xp professional included support 24-bit color sound client available windows 2000 windows 9x windows nt 4.0 version name client changed terminal services client remote desktop connection heritage remains day however underlying executable still named mstsc.exe version introduced windows server 2003 included support console mode connections session directory local resource mapping also introduces transport layer security tls 1.0 server authentication encrypt terminal server communications version built windows xp professional x64 edition windows server 2003 x64 x86 editions version introduced windows vista incorporated support windows presentation foundation applications network level authentication multi-monitor spanning large desktop support tls 1.0 connections version 6.0 client available windows xp sp2 windows server 2003 sp1/sp2 x86 x64 editions windows xp professional x64 edition microsoft remote desktop connection client macintosh os x also available support intel powerpc mac os versions 10.4.9 greater server 2012 support rdc 6.0 later version released february 2008 included windows server 2008 well windows vista service pack 1 client included windows xp sp3 addition changes related remote administrator connects console version new functionality introduced windows server 2008 connecting remotely individual programs new client-side printer redirection system makes client print capabilities available applications running server without install print drivers server version released manufacturing july 2009 included windows server 2008 r2 well windows 7 release also changed terminal services remote desktop services version new functions windows media player redirection bidirectional audio multi-monitor support aero glass support enhanced bitmap acceleration easy print redirection language bar docking rdp 7.0 client available windows xp sp3 windows vista sp1/sp2 kb969084 rdp 6.1 client rdp 7.0 client supported windows server 2003 x86 windows server 2003 windows xp professional x64 editions rdp 7.0 also supported windows server 2008 rdp 7.0 clients also support connecting terminal servers running windows 2000 server rdp 7.0 features like aero glass remote use bidirectional audio windows media player redirection multiple monitor support remote desktop easy print available windows 7 enterprise ultimate editions release 7.1 rdp included windows 7 service pack 1 windows server 2008 r2 sp1 2010 introduced remotefx provides virtualized gpu support host-side encoding version released windows 8 windows server 2012 version new functions adaptive graphics progressive rendering related techniques automatic selection tcp udp transport protocol multi touch support directx 11 support vgpu usb redirection supported independently vgpu support etc connection quality button displayed rdp client connection bar rdp 8.0 connections clicking provides information connection including whether udp use rdp 8.0 client server components also available add-on windows 7 sp1 rdp 8.0 client also available windows server 2008 r2 sp1 server components add-on requires dtls protocol installed prerequisite installing updates rdp 8.0 protocol enabled windows 7 machines extra configuration step needed using group policy editor new feature rdp 8.0 limited support rdp session nesting works windows 8 server 2012 though windows 7 server 2008 r2 even rdp 8.0 update support feature shadow feature rdp 7 allowed administrator monitor snoop rdp connection removed rdp 8 aero glass remoting feature applicable windows 7 machines connecting also removed rdp 8 version released windows 8.1 windows server 2012 r2 rdp 8.1 client update exists windows 7 sp1 well unlike rdp 8.0 update windows 7 add rdp 8.1 server component windows 7 furthermore rdp 8.0 server function desired windows 7 kb 2592687 rdp 8.0 client server components update must installed installing rdp 8.1 update support session shadowing added back rdp version 8.1 version also fixes visual glitches microsoft office 2013 running remoteapp version 8.1 rdp also enables restricted admin mode logging mode requires knowledge hashed password rather plaintext therefore making pass hash attack possible microsoft released 82-page document explaining mitigate type attack version 10.0 rdp includes following new features autosize zoom useful hidpi clients addition graphics compression improvements included utilizing h.264/avc microsoft introduced following features release rdp 6.0 2006 release 7.1 rdp 2010 introduced following feature version 5.2 rdp default configuration vulnerable man-in-the-middle attack administrators enable transport layer encryption mitigate risk rdp sessions also susceptible in-memory credential harvesting used launch pass hash attacks march 2012 microsoft released update critical security vulnerability rdp vulnerability allowed windows computer compromised unauthenticated clients computer worms rdp client version 6.1 used reveal names pictures users rdp server matter windows version order pick one username specified rdp connection march 2018 microsoft released patch remote code execution vulnerability credssp security support provider involved microsoft remote desktop windows remote management discovered preempt may 2019 microsoft issued security patch bluekeep vulnerability allows possibility remote code execution microsoft warned wormable potential cause widespread disruption unusually patches also made available several versions windows reached end-of-life windows xp immediate malicious exploitation followed experts unanimous likely could cause widespread harm based number systems appeared remained exposed unpatched july 2019 microsoft issued security patch rdp vulnerability affects hyper-v numerous non-microsoft implementations rdp clients servers implement subsets microsoft functionality instance open-source command-line client rdesktop available linux/unix microsoft windows operating systems many gui clients like tsclient krdc built top rdesktop cord client macintosh 2009 rdesktop forked freerdp new project aiming modularizing code addressing various issues implementing new features freerdp comes command-line-client xfreerdp supports seamless windows rdp6 โ also gtk-application named remmina open-source implementation remote desktop protocol server unix freerdp xrdp windows remote desktop connection client used connect server proprietary rdp client solutions rdpclient available stand-alone application embedded client hardware new access paradigm browser-based access enabled users access windows desktops applications rdp hosts microsoft remote desktop rds session hosts terminal services virtual desktops well remote physical pcs also so-called vrdp used virtualbox virtual machine implementation oracle protocol compatible rdp clients provided windows unlike original rdp configured accept unencrypted password unprotected connections may useful secure trusted networks home office lans default microsoft rdp server refuses connections user accounts empty passwords changed group policy editor external guest authorization options provided vrdp well matter operating system installed guest vrdp implemented virtual machine host level guest system proprietary virtualbox extension pack required microsoft requires third-party implementations license relevant rdp patents extent open-source clients meet requirement remains unknown security researchers reported cybercriminals selling compromised rdp servers underground forums well specialized illicit rdp shops compromised rdps may used staging ground conducting types fraud access sensitive personal corporate data researchers report instances cybercriminals using rdps directly drop malware computers
|
Internet protocols
|
simple instant messaging protocol simple session initiation protocol instant messaging presence leveraging extensions instant messaging im presence protocol suite based session initiation protocol sip managed internet engineering task force contrary vast majority im presence protocols used software deployed today simple open standard like xmpp simple applies sip problems implementations simple based protocols found sip softphones also sip hardphones simple presence specifications broken sip defines two modes instant messaging
|
Internet protocols
|
toshiba t3100 t3100 laptop manufactured toshiba released 1986 featured hard drive 8 mhz intel 80286 cpu black orange 9.6 gas-plasma display resolution 640x400 pixels laptop time special high-resolution 640 x 400 display mode similar partially compatible olivetti/at 6300 graphics single proprietary expansion slot 1200 bit/s modem expansion chassis 5x 8-bit isa cards ethernet nic 2400 bit/s modem 1 mb memory card thus 3.6 mb max total base model 1mb memory could upgraded 5mb toshiba t3100 true portable needed external power source except last version five versions existed japan japanese version t3100 marketed j-3100 byte 1989 listed t3100/20 among distinction winners byte awards citing amazingly clear display hard drive
|
Computer architecture
|
ti extended basic ti extended basic discontinued implementation basic programming language interpreter texas instruments ti-99/4a home computer ti produced extended basic cartridge greatly enhanced functionality accessible ti basic users sprites could generated set move automatically simple one-line commands custom call subprograms access memory expansion larger programs multiple statement lines statement separator boolean logic statements assembly language linkage well ability display text location screen added largely retaining compatibility ti basic equipped ti speech synthesizer ti extended basic users could also generate speech predefined vocabulary easily writing text on-screen example following line text entered command-line prompt would cause speech synthesizer identify computer multi-word phrases delimited symbol codice_1 example using word included speech synthesizer built-in vocabulary 338 words phrases would cause slowly spell word ti terminal emulator ii cartridge provided text-to-speech functionality ti extended basic also provided raw access speech synthesizer developers resources generate speech data function rarely used ti extended basic several statements present ti basic accept image linput break error warning sub subend subexit
|
Programming language topics
|
briefcase microsoft windows microsoft windows briefcase special folder supports simple two-way file synchronization another folder briefcase designed mobile pc users may transfer removable drive synchronize computer removable drive attached follows metaphor file file folder file management tasks performed windows explorer briefcase behaves like another folder i.e support copy-paste drag-and-drop additional functions toolbar buttons updating out-of-sync files windows briefcase introduced windows 95 windows briefcase synchronizes files folders within folder even removable writable media network intended users portable media multiple computers use briefcase users need use windows explorer drag copy files briefcase changes either files disk briefcase synchronized whenever user right-clicks briefcase selects update differences copies briefcase shows dialog box icon description indicating action take synchronizing whether replace copy briefcase external file vice versa action briefcase take configurable right clicking icon example users skip synchronizing individual items selecting skip action upon right clicking icon items deleted either briefcase main original folder briefcase create copy missing item users also sync individual items briefcase selecting item first clicking update button instead update update status item stored briefcase item link original item outside briefcase example drive containing briefcase inserted secondary computer original deleted main computer called orphan special folders windows briefcase folders hidden file system attribute called desktop.ini may also windows registry entries describing desktop.ini briefcase contains following lines second file called briefcase database bearing hidden system attributes filename extension serves briefcase index fourcc ddsh briefcase folder must read-only system file attributes default read-only order display briefcase desktop.ini briefcase database files required hidden system attributes order parent folder display briefcase user wishes sync file one another folder filename must exactly item renamed moved splits original longer synchronized becomes orphan item deleted associated copy default deleted well using update briefcase medium becomes full update space writing updated briefcase database effect making many folders files orphans easy way restore link counterparts source medium limitations others make briefcase files brittle easily corrupted limits robustness folder file backup mechanism
|
Computer file systems
|
islisp islisp also capitalized islisp programming language lisp family standardized international organization standardization iso international electrotechnical commission iec joint working group iso/iec jtc 1/sc 22/wg 16 commonly termed simply sc22/wg16 wg16 primary output working group international standard published iso standard updated 2007 republished iso/iec 13816:2007 e although official publication iso versions islisp language specification available believed public domain goal standards effort define small core language help bridge gap differing dialects lisp attempted accomplish goal studying primarily common lisp eulisp le lisp scheme standardizing features shared islisp design goals islisp separate function variable namespaces hence lisp-2 islisp object system ilos mostly subset common lisp object system clos islisp implementations made many operating systems including windows unix posix based linux macos freebsd openbsd netbsd solaris hp-ux aix cygwin qnx android dos os/2 pocket pc openvms z/os implementations hardware computer architectures include x86 x86-64 ia-64 sparc sparc9 powerpc mips alpha pa-risc arm aarch64 two older implementations longer available
|
Programming language topics
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.