text
stringlengths 6
1.88M
| source
stringclasses 13
values |
|---|---|
rock n bolt rock n bolt puzzle video game developed action graphics published 1984 activision colecovision commodore 64 msx sg-1000 objective game lock platforms place according supplied map three levels difficulty second third level time limits
|
Computer architecture
|
redos regular expression denial service redos algorithmic complexity attack produces denial-of-service providing regular expression takes long time evaluate attack exploits fact regular expression implementations exponential time worst case complexity time taken grow exponentially relation input size attacker thus cause program spend unbounded amount time processing providing regular expression either slowing becoming unresponsive regular expression matching done building finite-state automaton regular expressions easily converted nondeterministic automata nfas state input symbol may several possible next states building automaton several possibilities exist algorithms first two problematic first problematic deterministic automaton could formula_1 states formula_2 number states nondeterministic automaton thus conversion nfa dfa may take exponential time second problematic nondeterministic automaton could exponential number paths length formula_3 walking input length formula_3 also take exponential time last two algorithms however exhibit pathological behavior note non-pathological regular expressions problematic algorithms usually fast practice one expect compile regular expression time match n time instead simulation nfa lazy computation dfa mn worst-case complexity regular expression denial service occurs expectations applied regular expressions provided user malicious regular expressions provided user trigger worst-case complexity regular expression matcher regex algorithms written efficient way regular expression engines existence extend regular expression languages additional constructs always solved efficiently extended patterns essentially force implementation regular expression programming languages use backtracking malicious regexes get stuck crafted input different depending regular expression matcher attack backtracking matchers occur whenever factors occur second condition best explained example regular expression codice_1 match repeated subexpression codice_2 therefore matching nondeterministic automaton may try new match codice_2 new match input many consecutive double number possible paths automaton examples malicious regexes include following susceptible input minimum input length might change slightly using faster slower machines patterns may cause exponential behavior long enough inputs hundreds characters usually could still cause long elaboration times example pattern codice_9 input arbitrarily long sequence s. pattern may also cause backtracking matchers hang so-called evil malicious regexes found online regular expression repositories note enough find evil sub expression order attack full regex two examples also susceptible input regex affected user input attacker inject malicious regex make system vulnerable therefore cases regular expression denial service avoided removing possibility user execute arbitrary patterns server case web applications databases main vulnerable applications alternatively malicious page could hang user web browser cause use arbitrary amounts memory however examples paragraphs considerably less artificial others thus demonstrate vulnerable regexes may used result programming mistakes case e-mail scanners intrusion detection systems could also vulnerable fortunately cases problematic regular expressions rewritten non-evil patterns example codice_8 rewritten codice_13 case web application programmer may use regular expression validate input client server side system attacker could inspect client code looking evil regular expressions send crafted input directly web server order hang
|
Computer security
|
arj arj archived robert jung software tool designed robert k. jung creating high-efficiency compressed file archives arj currently version 2.86 dos 3.20 microsoft windows supports 16-bit 32-bit 64-bit intel architectures arj one two mainstream archivers dos windows early mid-1990s pkzip competition parts arj covered generally arj less popular pkzip niche market bbs era warez scene largely due arj creation handling multi-volume archives archives split smaller files suitable dial-up transfers floppy distribution robust pkzip arj compressed files filename extension .arj unpacked various tools arj software exists free software re-implementation tool software 7-zip zipeg winrar also unpack .arj files mac exists standalone utilities dearj unarjmac
|
Computer file systems
|
automated information systems security telecommunication automated information systems security comprises measures controls ensure confidentiality integrity availability information processed stored automated information systems unauthorized disclosure modification destruction may accidental intentional automated information systems security includes consideration computer hardware software functions characteristics features operational procedures accountability procedures access controls central computer facility remote computer terminal facilities management constraints physical structures devices computers transmission lines power sources personnel communications controls needed provide acceptable level risk automated information system data information contained system automated information systems security also includes totality security safeguards needed provide acceptable protection level automated information system data handled automated information system information security automated information systems security synonym computer security
|
Computer security
|
basex basex native light-weight xml database management system xquery processor developed community project github specialized storing querying visualizing large xml documents collections basex platform-independent distributed permissive free software license contrast document-oriented databases xml databases provide support standardized query languages xpath xquery basex highly conformant world wide web consortium w3c specifications official update full text extensions included gui enables users interactively search explore analyze data evaluate xpath/xquery expressions realtime i.e. user types basex uses tabular representation xml tree structures store xml documents database acts container single document collection documents xpath accelerator encoding scheme staircase join operator taken inspiration speeding xpath location steps additionally basex provides several types indices improve performance path operations attribute lookups text comparisons full-text searches basex started christian grün university konstanz 2005 2007 basex went open source bsd-licensed since basex server pure java 1.7 application thus runs system provides suitable java implementation tested windows mac os x linux openbsd particular packages available debian ubuntu
|
Databases
|
xml external entity attack xml external entity attack type attack application parses xml input attack occurs xml input containing reference external entity processed weakly configured xml parser attack may lead disclosure confidential data denial service server side request forgery port scanning perspective machine parser located system impacts xml 1.0 standard defines structure xml document standard defines concept called entity storage unit type different types entities external general/parameter parsed entity often shortened external entity access local remote content via declared system identifier system identifier assumed uri dereferenced accessed xml processor processing entity xml processor replaces occurrences named external entity contents dereferenced system identifier system identifier contains tainted data xml processor dereferences tainted data xml processor may disclose confidential information normally accessible application similar attack vectors apply usage external dtds external style sheets external schemas etc included allow similar external resource inclusion style attacks attacks include disclosing local files may contain sensitive data passwords private user data using file schemes relative paths system identifier since attack occurs relative application processing xml document attacker may use trusted application pivot internal systems possibly disclosing internal content via http requests launching csrf attack unprotected internal services situations xml processor library vulnerable client-side memory corruption issues may exploited dereferencing malicious uri possibly allowing arbitrary code execution application account attacks access local resources may stop returning data possibly impacting application availability many threads processes released note application need explicitly return response attacker vulnerable information disclosures attacker leverage dns information exfiltrate data subdomain names dns server control examples testing xml injection owasp-dv-008 xml version= 1.0 encoding= iso-8859-1 php expect module loaded remote code execution may possible modified payload xml version= 1.0 encoding= iso-8859-1 since entire xml document communicated untrusted client usually possible selectively validate escape tainted data within system identifier dtd therefore xml processor configured use local static dtd disallow declared dtd included xml document
|
Computer security
|
geeksphone revolution geeksphone revolution smartphone released geeksphone january 2014 uses x86 architecture pci bus instead arm architecture capable running either android firefox os lacks dual boot facility
|
Operating systems
|
instant messaging presence protocol instant messaging presence protocol impp ietf working group created purpose developing architecture simple instant messaging presence awareness/notification created 1999-02-25 concluded 2004-09-08
|
Internet protocols
|
green hills software green hills software privately owned company builds operating systems programming tools embedded systems firm founded 1982 dan o'dowd carl rosenberg world headquarters santa barbara california green hills software wind river systems enacted 99-year contract cooperative peers embedded software engineering market throughout 1990s relationship ending series lawsuits throughout early 2000s resulted opposite parting ways whereupon wind river devoted publicly embrace linux open-source software green hills initiated public relations campaign decrying use issues national security 2008 green hills integrity-178 rtos first system certified national information assurance partnership niap composed national security agency nsa national institute standards technology nist evaluation assurance level eal 6+ november 2008 announced commercialized version integrity 178-b available sold private sector integrity global security subsidiary green hills software march 27 2012 contract announced green hills software nintendo designates multi official integrated development environment toolchain nintendo licensed developers program wii u video game console february 25 2014 announced operating system integrity chosen urban aeronautics airmule integrity posix real-time operating system rtos integrity variant named integrity-178b certified common criteria evaluation assurance level eal 6+ high robustness november 2008 micro velosity stylized µ-velosity real-time microkernel resource-constrained devices green hills produces compilers programming languages c c++ fortran ada cross-platform 32- 64-bit microprocessors including arm blackfin coldfire mips powerpc superh starcore x86 v850 xscale multi integrated development environment ide programming languages c c++ embedded c++ ec++ ada aimed embedded engineers timemachine set tools optimizing debugging c c++ software timemachine introduced 2003 supports reverse debugging feature later also became available free gdb 7.0 debugger 2009
|
Computer architecture
|
vmlinux linux systems codice_1 statically linked executable file contains linux kernel one object file formats supported linux includes elf coff a.out codice_1 file might required kernel debugging symbol table generation operations must made bootable used operating system kernel adding multiboot header bootsector setup routines traditionally unix platforms called kernel image codice_3 development virtual memory kernels supported feature given codice_4 prefix differentiate name codice_1 mutation vmunix codice_6 letter codice_7 end denotes compressed example gzipped traditionally kernel located root directory filesystem hierarchy however bootloader must use bios drivers access hard disk limitations i386 systems meant first 1024 cylinders hard disk addressable overcome linux distributors encouraged users create partition beginning drives specifically storing bootloader kernel related files grub lilo syslinux common bootloaders convention partition mounted filesystem hierarchy codice_8 later standardised filesystem hierarchy standard fhs requires linux kernel image located either codice_9 codice_8 although technical restriction enforcing traditionally creating bootable kernel image kernel also compressed using gzip since linux 2.6.30 using lzma bzip2 requires small decompression stub included resulting image stub decompresses kernel code systems printing dots console indicate progress continues boot process support lzo lz4 compression later added decompression routine negligible factor boot time prior development bzimage size constraints architectures notably i386 extremely limiting making compression necessity sparc architecture vmlinux file compressed using simple gzip silo boot loader transparently decompresses gzipped images filename bootable image important many popular distributions use vmlinuz linux kernel matured size kernels generated users grew beyond limits imposed architectures space available store compressed kernel code limited bzimage big zimage format developed overcome limitation splitting kernel discontiguous memory regions bzimage compressed using gzip linux 2.6.30 introduced algorithms although popular misconception codice_11 prefix means bzip2 compression used bzip2 package often distributed tools prefixed codice_11 codice_13 codice_14 etc case bzimage file specific format contains concatenated codice_15 codice_16 codice_17 codice_18 codice_18 contains gzipped vmlinux file data section elf see compressed/makefile piggy.o source files mentioned codice_20 script codice_21 found codice_22 kernel sources decompresses kernel image distributions e.g red hat clones may come codice_23 rpm contains codice_1 file matching kernel rpm typically gets installed codice_25 codice_26 elf header x86-64 gentoo 2.6.29 executable kernel image readelf -h vmlinux elf header
|
Computer architecture
|
nepalinux nepalinux debian morphix-based linux distribution focused desktop usage nepali language computing contains applications desktop users openoffice.org nepali gnome kde desktops nepali input method editor development distribution nepalinux done madan puraskar pustakalaya version 1.0 produced part pan localization project support international development research centre idrc canada nepalinux effort promoting free open-source software nepal october 2007 nepalinux joint recipient association progressive communications annual apc foss prize
|
Operating systems
|
zen+ zen+ codename amd successor zen microarchitecture first released april 2018 powering second generation ryzen processors known ryzen 2000 mainstream desktop systems threadripper 2000 high-end desktop setups zen+ uses globalfoundries 12nm fabrication process optimization 14nm process used zen minor design rule changes means die sizes zen zen+ identical amd chose increase amount empty space individual smaller transistors improve power efficiency reduce thermal density rather design entirely new floor-plan physically smaller die process optimizations allowed zen+ achieve higher clock speeds lower power consumption zen products though minor revisions compared zen microarchitecture known changes microarchitecture include improved clock speed regulation response workload reduced cache memory latencies increased cache bandwidth better ddr4 sdram memory support zen+ also supports improvements per-core clocking features based core utilization cpu temperatures changes core utilization temperature power algorithms branded precision boost 2 xfr2 extended frequency range 2 evolutions first-generation technologies zen zen xfr gave additional 50 200 mhz clock speed increase 25 mhz increments maximum precision boost clocks zen+ xfr2 longer listed separate clock modifier instead xfr temperature power clock monitoring logic feeds precision boost 2 algorithm adjust clocks power consumption opportunistically dynamically ultimately changes zen+ resulted 3 improvement ipc zen conjunction 6 higher clock speeds resulted 10 overall increase performance
|
Computer architecture
|
loggly solarwinds loggly cloud-based log management analytics service provider based san francisco california jon gifford raffael marty kord campbell founded company 2009 charlie oppenheimer ceo loggly announced acquisition solarwinds part solarwinds cloud division brands january 8 2018 2009 jon gifford raffael marty kord campbell founded loggly assist companies solving operational issues app47 mobile application management provider partnered loggly september 2012 company chose loggly software-as-a-service saas deployment option september 2013 loggly released generation 2 updated version service update included log collection standard syslog protocols graphical web interface allowed users use point-and-click process find log events generate charts month loggly completed 10.5 million funding round led cisco data collective trinity ventures true ventures matrix partners also participated round october 2014 company announced 15 million series c funding round led harmony partners matrix partners trinity ventures cisco data collective true ventures also participated funding round raised loggly total investment funding 33.4 million company released loggly dynamic field explorer new user experience aims reduce time developers spend identifying troubleshooting problems month january 8 2018 company announced part solarwinds loggly headquartered san francisco california company 54 employees 10,000 customers october 2017 loggly records log data device reports real-time management platform trend data loggly cloud-based log management service provider require use proprietary software agents collect log data service uses open source technologies including elasticsearch apache lucene 4 apache kafka
|
Computer security
|
biobase company biobase international bioinformatics company headquartered wolfenbüttel germany focus generation maintenance licensing databases field molecular biology related software platforms history company founded 1997 spin-off german research centre biotechnology gbf braunschweig germany known today helmholtz research centre infection research *the founders scientists gbf research group bioinformatics headed time edgar wingender company managed michael tysiak ceo/cfo frank schacherer coo citation needed • company original product transfac database platform description analysis gene regulatory events networks subsequently complemented number smaller databases relevant aspects gene regulation early signaling pathway database transpath transpath constituted earliest signaling pathway database alongside cell signaling network database csndb curated t. takai national institute health sciences nihs tokyo • 1999 2000 employees till august 2017 biobase group new high-tech enterprise focusing development production management scientific equipment vitro diagnosis ivd instrument reagent • biobase group certificates including iso9001 iso13485 iso 14001 sgs ce nsf en fda etc • biobase group always adheres mission “ service health future ” promotes company ’ culture vigorously providing high quality products good service biobase would like establish win-win business cooperation distributors world end 1999 biobase acquired venture capital imh funds managed triginta capital mbg hannover 2007 tbg 2002 intec w g tokyo japan invested company remained shareholder 2005 early 2005 company acquired databases produced incyte wilmington delaware usa operated time incyte subsidiary proteome inc beverly early flagship proteome yeast proteome database ypd complemented number similar databases latest achievement acquisition human proteome survey database humanpsd biobase gmbh three fully owned daughter companies biobase corporation beverly/massachusetts usa since 2005 biobase databases india pvt ltd. bangalore india since 2006 biobase japan k.k yokohama japan since 2007 company databases provide manually curated content collected structured peer-reviewed scientific primary publications biobase knowledge library bkl integrated database comprising following modules addition biobase developed explain system biological interpretation gene expression proteomics data integrated functional promoter pathway analysis gene regulation portal offers number earlier revisions company products free charge users non-profit organizations number third-party products also distributed biobase addition products biobase offers knowledge process outsourcing kpo services may comprise development population customized databases specific contents systematic analyses gene expression data biobase member following publicly funded research consortia first two coordinated biobase alexander kel addition biobase entered research partnerships
|
Databases
|
spatial archive interchange format spatial archive interchange format saif pronounced safe defined early 1990s self-describing extensible format designed support interoperability storage geospatial data saif dataset saif two major components together define saiftalk first class syntax notation csn data definition language used define dataset schema second object syntax notation osn data language used represent object data adhering schema csn osn contained physical file along directory beginning file use ascii text straightforward syntax csn osn ensure parsed easily understood directly users developers saif dataset .saf .zip extension compressed using zip archive format schema definition saif defines 285 classes including enumerations class syntax notation covering definitions high-level features geometric types topological relationships temporal coordinates relationships geodetic coordinate system components metadata considered forming base schema using csn user defines new schema describe features given dataset classes belonging new schema defined csn subclasses existing saif classes new enumerations foreststand :myschema example could defined attributes including age species etc foreststand :myschema specified subclass geographicobject feature defined saif standard user defined classes must belong schema one defined user previously existing different schemas exist dataset objects defined one schema reference specified another inheritance saif supports multiple inheritance although common usage involved single inheritance object referencing object referencing used means breaking large monolithic structures significantly allow objects defined referenced number times section geometry land-water interface could define part coastline well part municipal boundary part marine park boundary geometric feature defined given object reference used geometry coastline municipality marine park specified multimedia multimedia objects also objects saif dataset referenced accordingly example image sound files associated given location could included primary advantage saif inherently extensible following object oriented principles meant data transfers one gis environment another need follow lowest common denominator two systems instead data could extracted dataset defined first gis transformed intermediary i.e. semantically rich saif model transformed model format applicable second gis notion model model transformation deemed realistic object oriented approach recognized scripts carry transformations could fact add information content safe software developed feature manipulation engine fme large measure express purpose supporting transformations fmebc freely available software application supported wide range transformations using saif hub fme developed commercial offering intermediary could held memory instead saif dataset saif project established means addressing interoperability different geographic information systems exchange formats particular prominence time included digest digital geographic information exchange standard sdts spatial data transfer specification later accepted spatial data transfer standard considered inflexible difficult use consequently government british columbia decided develop saif put forward national standard canada saif became canadian national standard 1993 approval canadian general standards board last version saif published january 1995 designated cgis-saif canadian geomatics interchange standard spatial archive interchange format formal definition release 3.2 issue can/cgsb-171.1-95 catalogue number p29-171-001-1995e work saif modeling paradigm csn classes carried principally mark sondheim henry kucera peter friesen british columbia government time dale lutz murray safe software developed object syntax notation reader writer software became part feature manipulation engine saif brought attention michael stonebraker kenn gardels university california berkeley working initial version open geospatial interoperability specification ogis first efforts became open geospatial consortium ogc series 18 submissions iso sql multimedia working group also helped tie saif original iso work geospatial features today saif historical interest significant precursor geography markup language formative element development widely used feature manipulation engine sondheim m. k. gardels k. buehler 1999 gis interoperability pp 347–358 geographical information systems second edition volume 1 edited paul a. longley michael f. goodchild david j. magurie davide w. rhind sondheim m. p. friesen d. lutz d. murray 1997 spatial archive interchange format saif spatial database transfer standards 2 characteristics assessing standards full descriptions national international standards world edited moellering h. hogan r. elsevier netherlands surveys resource mapping branch spatial archive interchange format release 3.2 formal definition 1995 also release 3.1 1994 3.0 1993 2.0 1992 1.0 1991 0.1 1990 surveys resource mapping branch british columbia ministry environment lands parks 258p also published canadian general standards board can/cgsb-171.1-95 available request geobc service desk http //www.ilmb.gov.bc.ca/geobc/servicedesk.html
|
Computer architecture
|
oracle media objects oracle media objects formerly oracle card software development tool developing multi-media applications functionality appearance similar apple computer hypercard program originated plus 1989 clone hypercard published format verlag added several highly-requested features plus purchased spinnaker software ported windows nt os/2 presentation manager becoming first cross-platform hypermedia solution 1994 plus purchased objectplus focussed windows version renaming winplus also licensed system oracle used basis oracle card first released 1991 oracle card essentially redistribution plus runtime engine along external libraries establishing connections rdbms engines oracle db2 oracle card stacks could execute queries associate results native variables making oracle card one first rdbms application development environments support cross-platform development years later oracle acquired original plus source code format verlag developed become oracle media objects omo omo n't last long development ceasing version 1.1.2 omo used oracle position video demand market commercially products built using tool amongst secret century series cd-roms published voyager company inside independence day aces entertainment omo unique distinction stacks cross-platform also external libraries xcmds purpose small subset mac os memory management commands handles ported platforms addition omo sported modular design every type object actually implemented plugin file objects folder omo object types included standard controls available hypercard clones time buttons text fields draw paint graphics well complex controls like spreadsheet field non-control items could placed card invisible runtime like timers could scheduled send messages specified time oracle card primary value lay fact time oracle product offer gui support microsoft windows therefore sometimes included sales pitches potential clients virtue fact windows becoming increasingly popular desktop large corporations showed customers oracle serious windows current product platform oracle primary application development tool oracle forms 3 character-based run microsoft windows although could run dos window natively dos without windows oracle desperately working developing upgrade oracle forms 4 gui features development behind schedule oracle card primarily used stop gap demonstration product oracle forms become available handful large clients including u.s postal service known developed applications oracle card internal use oracle card broad commercial success development platform despite fact feature set surpassed apple hypercard nearly every respect platform support database connectivity vector graphics support better color support faster performance richer plug-in architecture eventually oracle forms 4.0 released meaning support windows longer exclusive domain oracle card oracle customers tended interested standard forms-based database applications rather sorts multimedia applications possible create oracle card successor omo oracle eventually threw full weight behind oracle forms 4.0 casting oracle card/omo oblivion however oracle card team led two oracle employees gone form successful technology companies marc benioff founder salesforce.com evan goldberg founder netsuite
|
Programming language topics
|
clanlib clanlib video game sdk supporting microsoft windows macos linux partial support mobile platforms full hardware accelerated graphics support opengl also software renderer clanlib also helps playing sound using vorbis mikmod libraries classes collision detection guis xml networking things may helpful game programmer earliest known public release 1999 version 0.1.18 introduction c++ game programming published june 2007 dedicates chapter learn use clanlib library make 2d games also game programming python lua ruby published december 2003 chapter using clanlib together ruby
|
Operating systems
|
eagles guidelines eagles guidelines provide guidance markup used text corpora particularly identifying features relevant computational linguistics lexicography expert advisory group language engineering standards eagles initiative european commission within dg xiii linguistic research engineering programme numerous well-known companies research centres universities professional bodies across european union collaborate aegis ec dgxiii produce eagles guidelines set recommendations de facto standards good practice areas language engineering eagles initiative coordinated consorzio pisa ricerche pisa italy eagles aims accelerate provision standards
|
Computational linguistics
|
miracle warriors seal dark lord miracle warriors seal dark lord known japan role-playing video game released initially japanese pc-88 ported various systems including sega master system version released north america screen game consists four parts lower left character statistics lists characters party character life bar experience bar single character gain experience hitting enemies experiences full new level reached experience bar emptied bars extended resulting maximum life character experience needed gain new level lower right statistics entire party example amount money upper right section varies screen screen traveling world town maze map shown player navigate player invokes main menu shown battle shows battle menu upper left section also varies traveling world cave shows party members surroundings battle shows foe town shows persons player talk dialogue player encounters enemy screen switches battle mode battle mode player choose one character attack per turn character also subjected attack enemy unless enemy uses spell attacks multiple players enemies use flame spells attack party members sleep spells put multiple party members sleep every time party member put sleep take damage wake put sleep many times battle taking damage time fall asleep every party member sleeping enemy use flame spell attack every party member alternative attack player several options including talking retreating using magical item casting spell enemies respond talking give hints currency game guilder used buy items heal players defeated enemies also yield fangs proof valor battle fangs used buy exclusive items traded villages guilders defeating enemies also increase decrease player character points fame killing monsters usually increases player fame killing good characters example merchants decreases player fame certain amount character points required enter certain villages game takes place world five lands spread three continent came elaborate grid-format map noting areas interest game four types land plain forest mountains desert enemies become dangerous different types land plains safest terrain cross continents separated oceans storming sea around last continent ship required sail oceans special ship needed cross storming sea helmed someone pirate blood veins throughout world several towns towns smiths repair weapons armor healers heal sell herbs shops sell weapons armor towns provide information one person every town buys fangs fifty guilders also villages serve special purposes selling ships special magical items several caves exist world house guardians protect mystical armors legend finally also various castles visited get weapons legends kings impressed enough demon queen terarin テラリン returned stolen golden seal opened pandora passage letting loose dark creatures world young hero tasked king restore peace world must step footsteps ancestor iason fought seal demoness another dimension finish job bring end terarin evil hero must enlist aid three companions guy warrior medi amazon treo pirate called turo english manual find three keys terarin lair underground temple defeat also need find set ancient mystical weapons armor miracle warriors master system received mixed mostly positive reviews including rated 40 games machine 77 sega power 80 tilt game followed sequel titled wings arugisu アルギースの翼 released msx2 kogado 1988
|
Computer architecture
|
hybrid automatic repeat request hybrid automatic repeat request hybrid arq harq combination high-rate forward error-correcting coding arq error-control standard arq redundant bits added data transmitted using error-detecting ed code cyclic redundancy check crc receivers detecting corrupted message request new message sender hybrid arq original data encoded forward error correction fec code parity bits either immediately sent along message transmitted upon request receiver detects erroneous message ed code may omitted code used perform forward error correction fec addition error detection reed–solomon code fec code chosen correct expected subset errors may occur arq method used fall-back correct errors uncorrectable using redundancy sent initial transmission result hybrid arq performs better ordinary arq poor signal conditions simplest form comes expense significantly lower throughput good signal conditions typically signal quality cross-over point simple hybrid arq better basic arq better simplest version harq type harq adds ed fec information message prior transmission coded data block received receiver first decodes error-correction code channel quality good enough transmission errors correctable receiver obtain correct data block channel quality bad transmission errors corrected receiver detect situation using error-detection code received coded data block rejected re-transmission requested receiver similar arq sophisticated form type ii harq message originator alternates message bits along error detecting parity bits fec parity bits first transmission received error free fec parity bits never sent also two consecutive transmissions combined error correction neither error free understand difference type type ii hybrid arq consider size ed fec added information error detection typically adds couple bytes message incremental increase length fec hand often double triple message length error correction parities terms throughput standard arq typically expends percent channel capacity reliable protection error fec ordinarily expends half channel capacity channel improvement standard arq transmission must received error free given transmission error detection pass type ii hybrid arq first transmission contains data error detection different standard arq received error free done data received error second transmission contain fec parities error detection received error free done received error error correction attempted combining information received transmissions type hybrid arq suffers capacity loss strong signal conditions type ii hybrid arq fec bits transmitted subsequent re-transmissions needed strong signal conditions type ii hybrid arq performs good capacity standard arq poor signal conditions type ii hybrid arq performs good sensitivity standard fec practice incorrectly received coded data blocks often stored receiver rather discarded re-transmitted block received two blocks combined called hybrid arq soft combining dahlman et al. p. 120 possible two given transmissions independently decoded without error may happen combination previously erroneously received transmissions gives us enough information correctly decode two main soft combining methods harq several variants two main methods exist example partial chase combining subset bits original transmission re-transmitted partial incremental redundancy systematic bits always included re-transmission self-decodable example incremental redundancy harq hsdpa data block first coded punctured 1/3 turbo code transmission coded block usually punctured i.e fraction coded bits chosen sent puncturing pattern used transmission different different coded bits sent time although hsdpa standard supports chase combining incremental redundancy shown incremental redundancy almost always performs better chase combining cost increased complexity harq used stop-and-wait mode selective repeat mode stop-and-wait simpler waiting receiver acknowledgment reduces efficiency thus multiple stop-and-wait harq processes often done parallel practice one harq process waiting acknowledgment another process use channel send data forward error correction codes used harq scheme besides turbo codes e.g extended irregular repeat-accumulate eira code efficiently-encodable rate-compatible e2rc code low-density parity-check codes harq used hsdpa hsupa provide high speed data transmission downlink uplink respectively mobile phone networks umts ieee 802.16-2005 standard mobile broadband wireless access also known mobile wimax also used evolution-data optimized lte wireless networks type hybrid arq used itu-t g.hn high-speed local area network standard operate data rates 1 gbit/s existing home wiring power lines phone lines coaxial cables g.hn uses crc-32c error detection ldpc forward error correction selective repeat arq
|
Internet protocols
|
computer liquidator computer liquidator buys computer technology related equipment longer required one company resells flips another company computer liquidators agents act computer recycling electronic recycling business several reasons companies sell liquidate used information technology i.t equipment bankruptcy downsizing expanding technological advancement technological advancement common reason equipment longer performing tasks required usually rendered obsolete advanced technology coming market used obsolete technology often referred electronic waste equipment designated outdated one company still viable another company whose operations may require advanced solutions often information technology audit performed help company decide equipment needs updating requirements computer liquidation sustainable solution environmentally friendly rapid technology change low initial cost planned obsolescence resulted fast-growing surplus computers electronic components around globe purpose computer liquidators keep many computers electronic parts landfills newer better technology replaces hardware ever-increasing speed amount technical trash increases technology replaced speed hardware changes innovates last years follows degree moore law predictions made every landfill would soon overflowing discarded computer screens computers along associated equipment keyboards mouses hardware associated use internet.most electronic waste sent landfills incinerated releases toxic materials lead mercury cadmium soil groundwater atmosphere thus negative impact environment best liquidating companies clearly outlined policies regarding disposal dangerous substances often issue information technology act liquidation avoids possible toxins pollution comes putting electronic waste landfills also avoids extra costs go recycling example new york passed law 2015 banned putting electronic devices landfills waste facilities rural counties forced either turn people away eat cost recycling cathode ray tubes outside new york city counties spending 6 million 10 million year deal problem according stephen acquario executive director new york state association counties option liquidation actually incentivizes people get rid electronic waste safer way since recycling actually costs owner money cases people would rather throw avoid recycling fee computer liquidators effectively create secondary market meet demand looking cheaper solution require cutting edge technology important note equipment liquidated ranges new technology old technology relatively lower price secondary market equipment companies may even purchase tech devices secondary market use backups stocking equipment preemptively replacement always hand event trouble product availability also another reason buyers buy market manufacturers generally refresh product line every 12 24 months typically liquidating older products networking hardware often see service lives five years resellers computer liquidators might carry products upwards decade old end users use particular product may find much easier cheaper add/replace older device rather take costs business disruptions knowledge gaps occur upgrading new products newer products adopted used equipment inevitably liquidated thrown sold back creates robust marketplace typically three agents computer liquidation process seller computer liquidator buyer sellers companies bankrupt need sell assets companies downsizing expanding companies upgrading technology usually companies looking sell equipment first conduct information technology audit review systems equipment process generally fueled supply side computer liquidators rely available market liquidate resell thus nearly always exists shortage buyers oceantech example buys computers laptops tablets electronics companies longer need technology conduct certified data destruction appliances technicians perform thorough check systems confirm devices functional stored warehouse certain parts like motherboard hard drives able used stripped machine put warehouse store devices parts resold smaller companies places like school districts need products companies involved computer liquidation business also heavily involved computer electronic recycling industry takes similar process disassembling testing process theoretically benefits ends exchange seller gets money equipment longer needs buyer gets cheap equipment necessary work number organizations sprung provide technical guidelines handling dealing ewaste
|
Computer security
|
joy programming language joy programming language computer science purely functional programming language produced manfred von thun la trobe university melbourne australia joy based composition functions rather lambda calculus turned many similarities forth due design sort parallel evolution convergence also inspired function-level programming style backus fp joy unusual except function-level programming languages esoteric ones unlambda lack lambda operator therefore lack formal parameters illustrate common example square function might defined imperative programming language c variable x formal parameter replaced actual value squared function called functional language scheme function could defined different many ways still uses formal parameter x way joy square function defined joy everything function takes stack argument returns stack result instance numeral 5 represent integer constant instead short program pushes number 5 onto stack square function makes copy top element multiplies two top elements stack leaving square original top element top stack need formal parameter makes joy concise illustrated definition quicksort binrec one joy many recursive combinators implementing binary recursion expects four quoted programs top stack represent joy meaning function homomorphism syntactic monoid onto semantic monoid syntactic relation concatenation symbols maps directly onto semantic relation composition functions homomorphism rather isomorphism onto one-to-one symbol one meaning sequences symbols meaning e.g dup 2 joy concatenative programming language concatenation two programs denotes composition functions denoted two programs library routines mirror iso c though current implementation easily extensible functions written c
|
Programming language topics
|
drda distributed relational database architecture drda database interoperability standard open group drda describes architecture distributed relational databases defines rules accessing distributed data provide actual application programming interfaces apis perform access first used db2 2.3 drda designed work group within ibm period 1988 1994 messages protocols structural components drda defined distributed data management architecture
|
Internet protocols
|
ace aces video game ace aces combat flight simulator developed artech digital entertainment published 1986 three different companies accolade u.s. gold tiertex design studios released amstrad cpc atari 8-bit family atari 7800 commodore 64 msx ms-dos master system zx spectrum set world war ii player flies raf mosquito long range fighter-bomber equipped rockets bombs cannon missions include destroying german fighter planes bombers v-1 flying bombs u-boats trains 1988 atari corporation released version cartridge styled then-new atari xegs ace aces received mixed reviews went become one best-selling commodore 64 video games published accolade upon launching game menu screen options either practice partake proper mission shown player decides practice mode choose whether dog fight training u-boat train bombing playing practice mode enemies less aggressive five different view options — cockpit left right wings navigational map bomb bay — accessed using keyboard double-tapping fire button moving joystick desired direction missions player controls twin-engined balsa raf mosquito already airborne mitigating necessity takeoff starting mission player chooses supplies wish bring player brings lower maximum speed plane end missions landing required points awarded according many enemies shot along amount unused fuel bombs missiles missions completed player choose combine two missions produce mashup 1987 compute article ace aces noted accolade second best selling commodore 64 game compute along reviewers praised graphics sound ace aces 1991 1993 computer gaming world surveys strategy war games gave one half stars five calling somewhat ahistorical issue 20 zzap 64 reviewer said best factual war simulation played compared dambusters said playability better desert fox also used comparison referred sometimes unbelievable article computer video games magazine published 1986 said another well-made well-presented game accolade continued say action-packed gameplay would able keep even critical computer pilot busy time come four criteria highly rated graphics getting 10 along sound value playability getting 8 graphics along sound features highly praised commodore 64 version n't highly acclaimed master system version chad reinhardt defunct games mentioned ace aces starts potential poor controls lack ability interact plane makes forgettable reinhardt criticised different practise mode main game continued adding little help actually helps attempting missions gave game d+ overall reviewers commented feeling excitement playing sega version review kultboy given rating 20 said reasoning behind low review plane meant fighter plane flies like tanker comparatively score graphics game given high 68 sega pro gave game rating 56 praised graphics static continued say impractical in-game zx spectrum version met reviews disliking complexity changing controls may distracting dogfight issue 38 sinclair reviewers ben stone paul sumner mike dunn criticised difficulty game game contains enough gameplay days steve panak writing analog computing preferred ace aces infiltrator atari 8-bit flight simulator
|
Computer architecture
|
internet explorer 11 internet explorer 11 ie11 eleventh final version internet explorer web browser microsoft officially released october 17 2013 windows 8.1 november 7 2013 windows 7 browser also shipped windows 10 release july 29 2015 microsoft edge default browser version windows default browser shipped windows server 2016 windows server 2019 january 12 2016 recent version internet explorer offered installation given windows operating system continue supported security updates lasting end support lifecycle windows operating system windows 7 8.1 internet explorer 11 receive security updates remainder windows versions support lifecycles internet explorer 10 reach end support january 31 2020 ie 11 supported version internet explorer windows server 2012 windows embedded 8 standard ie 11 available piloting windows server 2012 windows embedded 8 standard starting spring 2019 ie11 features redesigned developer tools support webgl enhanced scaling high dpi screens prerender prefetch launch ie11 got support http/2 addition ie11 supports full screen orientation apis css border image support javascript enhancements dom mutation observers web cryptography api video text track support encrypted media support improved html editor ie11 uses transport layer security v1.2 default protocol secure connections deprecates rc4 cipher suite internet explorer 11 windows rt support java add-ons november 2013 review sitepoint ie11 scored better google chrome 30 firefox 26 webkit sunspider test google webgl test tied chrome fastest microsoft fish aquarium benchmark webgl came last google v8 performance benchmark result speed improvements reviewer said switched chrome speed alone 're using wrong browser ie11 also observed use less memory multiple tabs open contemporary versions chrome firefox august 2015 sitepoint benchmarked ie11 review microsoft edge edge 12 chrome 44 firefox 39 also present ie11 came last apple jetstream test replaced sunspider google octane test replaces v8 came second microsoft fish aquarium test edge though internal build ie11 leaked march 25 2013 first preview version formally released june 2013 build 2013 conference along preview release windows server 2012 r2 windows 8.1 july 25 2013 microsoft released developer preview internet explorer 11 windows 7 windows server 2008 r2 releases internet explorer update windows 7 8.1 released april 2 2014 added enterprise mode improved developer tools improved support webgl ecmascript 5.1
|
Operating systems
|
quickstart quickstart loading method used several different software applications designed speed loading time software load core files libraries computer startup allows applications start quickly selected later quickstarters typically place icon system tray full application needs loaded base components already ram significantly reduces load time quickstarters controversial use ram even application open reason quickstarters actually decrease performance whole example six applications load quickstarter system tray 50 megabytes per piece 300 megabytes ram could otherwise used working applications user 256 megabytes ram cause running applications page virtual memory drastically reduce performance hand user one gigabyte ram running applications probably paged load times quickstart applications reduced resulting higher overall performance point user powers system system ready use delayed system must incur performance penalty form reading quickstart applications hard drive additional cpu processing sub-system usage quickstart application loaded memory following examples applications use quickstart method quickstarters workaround poor performance hard disk drives hdds traditionally standard desktop computers solid-state drives ssds lower latency faster seek times hdds less need quickstarters ssds ssd slowly becoming popular certain types computers business setting quickstart also informal often short description accomplish specific task generally meant help non-experts leave details important experts may also greatly simplified overall discussion topic
|
Operating systems
|
information sensitivity information sensitivity control access information knowledge might result loss advantage level security disclosed others loss misuse modification unauthorized access sensitive information adversely affect privacy welfare individual trade secrets business even security international relations nation depending level sensitivity nature information refers information already matter public record knowledge regard government private organizations access release information may requested member public often formal processes laid accessibility government-held public records important part government transparency accountability citizens values democracy public records may furthermore refer information identifiable individuals considered confidential including limited census records criminal records sex offender registry files voter registration includes business information subjected special protection may routinely shared anyone inside outside business confidential information used general sense mean sensitive information whose access subject restriction may refer information individual well pertains business however situations release personal information could negative effect owner example person trying avoid stalker inclined restrict access personal information furthermore person ssn sin credit card numbers financial information may considered private disclosure might lead crimes identity theft fraud types private information including records person health care education employment may protected privacy laws unauthorized disclosure private information make perpetrator liable civil remedies may cases subject criminal penalties even though often used interchangeably personal information sometimes distinguished private information personally identifiable information latter distinct former private information used identify unique individual personal information hand information belonging private life individual used uniquely identify individual range individual ’ favourite colour details domestic life latter common example personal information also regarded sensitive individual sharing details trusted listener would prefer shared anyone else sharing may result unwanted consequences confidential business information refers information whose disclosure may harm business information may include trade secrets sales marketing plans new product plans notes associated patentable inventions customer supplier information financial data classified information generally refers information subject special security classification regulations imposed many national governments disclosure may cause harm national interests security protocol restriction imposed upon information categorized hierarchy classification levels almost every national government worldwide restricted levels containing information may cause greatest danger national security leaked authorized access granted individuals need know basis also passed appropriate level security clearance classified information reclassified different level declassified made available public depending changes situation new intelligence classified information may also denoted method communication access example protectively marked secret eyes protectively marked secret encrypted transfer indicating document must physically read recipient openly discussed example telephone conversation communication sent using encrypted means often mistakenly listed meaning eyes intended recipient anomaly becomes apparent additional tag within windowed area also used data privacy concerns exist various aspects daily life wherever personal data stored collected internet medical records financial records expression political opinions 80 countries world personally identifiable information protected information privacy laws outline limits collection use personally identifiable information public private entities laws usually require entities give clear unambiguous notice individual types data collected reason collection planned uses data consent-based legal frameworks explicit consent individual required well european union data protection directive provides rigorous standard privacy protection legislation across member states although directive legally binding member states expected enact national privacy legislation within three years directive ’ adoption conforms standards since adoption directive demonstrated significant influence privacy legislation non-eu nations requirements privacy laws non-member nations engaging transborder flows private data eu member nations eu passed general data protection regulation gdpr replace directive regulation adopted 27 april 2016 becomes enforceable 25 may 2018 two-year transition period unlike directive require national governments pass enabling legislation thus directly binding applicable proposed new eu data protection regime extends scope eu data protection law foreign companies processing data eu residents provides harmonisation data protection regulations throughout eu thereby making easier non-european companies comply regulations however comes cost strict data protection compliance regime severe penalties 4 worldwide turnover gdpr also brings new set digital rights eu citizens age economic value personal data increasing digital economy canada personal information protection electronic documents act pipeda regulates collection use personal data electronic documents public private organizations pipeda effect federal provincial jurisdictions except provinces existing privacy laws determined “ substantially similar ” even though unified sensitive information framework united states implemented significant amount privacy legislation pertaining different specific aspects data privacy emphasis privacy healthcare financial e-commerce educational industries federal state levels whether regulated self regulated laws require establish ways access sensitive information limited people different roles thus essence requiring establishment sensitive data domain model mechanisms protection domains guideline form pre-defined models safe harbor hipaa based research latanya sweeny established privacy industry metrics additionally many countries enacted legislature regarding data privacy protection still process confidentiality sensitive business information established non-disclosure agreements legally binding contract two parties professional relationship ndas may one-way case employee receiving confidential information employing organization two-way businesses needing share information one another accomplish business goal depending severity consequences violation non-disclosure may result employment loss loss business client contacts criminal charges civil lawsuit hefty sum damages ndas signed employer employee initiation employment non-compete clause may part agreement added protection sensitive business information employee agrees work competitors start competing business within certain time geographical limit unlike personal private information internationally recognized framework protecting trade secrets even agreed-upon definition term “ trade secret ” however many countries political jurisdictions taken initiative account violation commercial confidentiality criminal civil laws example us economic espionage act 1996 federal crime united states misappropriate trade secrets knowledge benefit foreign power injure owner trade secret commonly breach commercial confidentiality falls civil law united kingdom developing countries trade secret laws either non-existent poorly developed offer little substantial protection many countries unauthorized disclosure classified information criminal offence may punishable fines prison sentence even death penalty depending severity violation less severe violations civil sanctions may imposed ranging reprimand revoking security clearance subsequent termination employment whistleblowing intentional disclosure sensitive information third-party intention revealing alleged illegal immoral otherwise harmful actions many examples present former government employees disclosing classified information regarding national government misconduct public media spite criminal consequences await espionage spying involves obtaining sensitive information without permission knowledge holder use spies part national intelligence gathering countries used political strategy nation-states since ancient times unspoken knowledge international politics countries spying one another time even allies computer security information security applied computing network technology significant ever-growing field computer science term computer insecurity hand concept computer systems inherently vulnerable attack therefore evolving arms race exploit existing vulnerabilities security systems must engineer new mechanisms security number security concerns arisen recent years increasing amounts sensitive information every level found primary existence digital form personal level credit card fraud internet fraud forms identity theft become widespread concerns individuals need aware day-to-day basis existence large databases classified information computer networks also changing face domestic international politics cyber-warfare cyber espionage becoming increasing importance national security strategy nations around world estimated 120 nations around world currently actively engaged developing deploying technology purposes philosophies internet cultures open-source governance hacktivism popular hacktivist slogan information wants free reflects cultural shifts perception towards political government secrecy popular controversial wikileaks one many manifestations growing cultural sentiment becoming additional challenge security integrity classified information
|
Computer security
|
database trigger database trigger procedural code automatically executed response certain events particular table view database trigger mostly used maintaining integrity information database example new record representing new worker added employees table new records also created tables taxes vacations salaries triggers also used log historical data example keep track employees previous salaries follows series descriptions popular dbms support triggers addition triggers fire execute pl/sql code data modified oracle 10g supports triggers fire schema-level objects tables modified user logon logoff events occur four main types triggers oracle 8i database events logons logoffs startups fire oracle triggers full list available msdn performing conditional actions triggers testing data following modification done accessing temporary inserted deleted tables introduced support triggers 1997 following functionality previously implemented postgresql synopsis firebird supports multiple row-level insert update delete combination thereof triggers per table always addition default table changes order triggers relative specified would otherwise ambiguous position clause triggers may also exist views always instead triggers replacing default updatable view logic version 2.1 triggers views deemed updatable would run addition default logic firebird raise mutating table exceptions like oracle triggers default nest recurse required sql server allows nesting recursion default firebird triggers use new old context variables inserted deleted tables provide updating inserting deleting flags indicate current usage trigger version 2.1 firebird additionally supports following database-level triggers database-level triggers help enforce multi-table constraints emulate materialized views exception raised transaction commit trigger changes made trigger far rolled back client application notified transaction remains active commit never requested client application continue make changes re-request commit syntax database triggers ibm db2 distributed systems known db2 luw luw means linux unix windows supports three trigger types trigger trigger instead trigger statement level row level triggers supported triggers operation table firing order determined trigger creation data since version 9.7 ibm db2 supports autonomous transactions trigger checking data deciding operation permitted exception thrown trigger operation aborted data changed db2 triggers read — ca n't modify data triggers triggers designed post processing requested change performed triggers write data tables unlike databases write table including table trigger operates instead triggers making views writeable triggers usually programmed sql pl language sqlite supports row-level triggers statement-level triggers updateable views supported sqlite emulated instead triggers example implementation triggers non-relational database sedna provides support triggers based xquery triggers sedna designed analogous triggers natively base xml query update languages xpath xquery xml update language trigger sedna set nodes xml document stored database nodes updated trigger automatically executes xquery queries updates specified body example following trigger cancels person node deletion open auctions referenced person understand trigger behavior works need aware two main types triggers row statement level triggers distinction two many times code within trigger executed time suppose trigger made called update certain table row level triggers would execute row affected update important keep mind rows affected update command trigger execute code within trigger statement level triggers called regardless many rows affected update important note even update command n't affect rows code within trigger still executed using options determine trigger called suppose trigger called insert certain table trigger using option code within trigger executed insert table occurs common use trigger verify input values insert modify values accordingly let say trigger uses instead code within trigger executed insert happens table example use trigger creating audit history made inserts database keeping track changes made using options need keep things mind option allow modify tables input validation practical use using triggers allows modify tables inserting audit history table creating trigger determine statement row level simply include row clause row level omit clause statement level cautious using additional insert/update/delete commands within trigger trigger recursion possible causing unwanted behavior examples trigger modifying different table looking modified see common applications different trigger types used oracle syntax example row level trigger called update row affected trigger called update phone book database trigger called adds entry separate table named phone_book_audit also take note triggers able take advantage schema objects like sequences example audit_id_sequence.nexval used generate unique primary keys phone_book_audit table calling update phone_book table people last name 'jones /div g notice phone_number_audit table populated two entries due database two entries last name 'jones since update modified two separate row values created trigger called twice modification oracle syntax statement trigger called update phone_book table trigger gets called makes insert phone_book_edit_history table lets exactly update example however time statement level trigger /div see trigger called even though update change two rows example row trigger modifies insert using conditional last name larger 10 letters using substr function change last_name column value abbreviation lets perform insert someone large name /div see trigger worked modifying value insert executed using statement trigger particularly useful enforcing database restrictions example going enforce restriction upon someone named someuser table phone_book someuser logged attempting insert error message show custom errors one restriction num variable defined numerous pre-defined errors variable must range -20000 -20999
|
Databases
|
quantum error correction quantum error correction qec used quantum computing protect quantum information errors due decoherence quantum noise quantum error correction essential one achieve fault-tolerant quantum computation deal noise stored quantum information also faulty quantum gates faulty quantum preparation faulty measurements classical error correction employs redundancy simplest way store information multiple times and—if copies later found disagree—just take majority vote e.g suppose copy bit three times suppose noisy error corrupts three-bit state one bit equal zero two equal one assume noisy errors independent occur probability p likely error single-bit error transmitted message three ones possible double-bit error occurs transmitted message equal three zeros outcome less likely outcome copying quantum information possible due no-cloning theorem theorem seems present obstacle formulating theory quantum error correction possible spread information one qubit onto highly entangled state several physical qubits peter shor first discovered method formulating quantum error correcting code storing information one qubit onto highly entangled state nine qubits quantum error correcting code protects quantum information errors limited form classical error correcting codes use syndrome measurement diagnose error corrupts encoded state reverse error applying corrective operation based syndrome quantum error correction also employs syndrome measurements perform multi-qubit measurement disturb quantum information encoded state retrieves information error syndrome measurement determine whether qubit corrupted one outcome operation syndrome tells us physical qubit affected also several possible ways affected latter counter-intuitive first sight since noise arbitrary effect noise one distinct possibilities codes effect either bit flip sign phase flip corresponding pauli matrices x z reason measurement syndrome projective effect quantum measurement even error due noise arbitrary expressed superposition basis operations—the error basis given pauli matrices identity syndrome measurement forces qubit decide certain specific pauli error happened syndrome tells us let pauli operator act corrupted qubit revert effect error syndrome measurement tells us much possible error happened nothing value stored logical qubit—as otherwise measurement would destroy quantum superposition logical qubit qubits quantum computer repetition code works classical channel classical bits easy measure repeat stops case quantum channel due no-cloning theorem longer possible repeat single qubit three times overcome different method so-called three-qubit bit flip code used technique uses entanglement syndrome measurements comparable performance repetition code consider situation want transmit state single qubit formula_1 noisy channel formula_2 let us moreover assume channel either flips state qubit probability formula_3 leaves unchanged action formula_2 general input formula_5 therefore written formula_6 let formula_7 quantum state transmitted error correcting protocol place transmitted state correctly transmitted probability formula_8 however improve number encoding state greater number qubits way errors corresponding logical qubits detected corrected case simple three-qubit repetition code encoding consists mappings formula_9 formula_10 input state formula_1 encoded state formula_12 mapping realized example using two cnot gates entangling system two ancillary qubits initialized state formula_13 encoded state formula_14 passed noisy channel channel acts formula_14 flipping subset possibly empty qubits qubit flipped probability formula_16 single qubit flipped probability formula_17 two qubits flipped probability formula_18 three qubits flipped probability formula_19 note assumption channel made assume formula_2 acts equally independently three qubits state encoded problem detect correct errors without time corrupting transmitted state let us assume simplicity formula_3 small enough probability single qubit flipped negligible one detect whether qubit flipped without also querying values transmitted asking whether one qubits differs others amounts performing measurement four different outcomes corresponding following four projective measurements formula_22this achieved example measuring formula_23 formula_24 reveals qubits different others without time giving information state qubits outcome corresponding formula_25 obtained correction applied outcome corresponding formula_26 observed pauli x gate applied formula_27-th qubit formally correcting procedure corresponds application following map output channel formula_28note procedure perfectly corrects output zero one flips introduced channel one qubit flipped output properly corrected example first second qubits flipped syndrome measurement gives outcome formula_29 third qubit flipped instead first two assess performance error correcting scheme general input study fidelity formula_30 input formula_14 output formula_32 output state formula_33 correct one qubit flipped happens probability formula_34 write formula_35 dots denote components formula_33 resulting errors properly corrected protocol follows formula_37this fidelity compared corresponding fidelity obtained error correcting protocol used shown equal formula_38 little algebra shows fidelity error correction greater one without formula_39 note consistent working assumption made deriving protocol formula_3 small enough flipped bits kind error classical computer another possibility error quantum computers sign flip transmission channel relative sign formula_41 formula_42 become inverted instance qubit state formula_43 may sign flip formula_44 original state qubit formula_45 changed state formula_46 hadamard basis bit flips become sign flips sign flips become bit flips let formula_47 quantum channel cause one phase flip bit flip code recover formula_48 transforming hadamard basis transmission formula_47 error channel may induce either bit flip sign flip possible correct types errors using one code shor code fact shor code corrects arbitrary single-qubit errors let formula_50 quantum channel arbitrarily corrupt single qubit 1st 4th 7th qubits sign flip code three group qubits 1,2,3 4,5,6 7,8,9 designed bit flip code shor code qubit state formula_51 transformed product 9 qubits formula_52 bit flip error happens qubit syndrome analysis performed set states 1,2,3 4,5,6 7,8,9 correct error three bit flip group 1,2,3 4,5,6 7,8,9 considered three inputs shor code circuit reduced sign flip code means shor code also repair sign flip error single qubit shor code also correct arbitrary errors bit flip sign flip single qubit error modeled unitary transform u act qubit formula_48 formula_56 described form formula_58 formula_59 formula_60 formula_61 complex constants identity pauli matrices given u equal error occurs formula_65 bit flip error occurs formula_66 sign flip error occurs formula_67 bit flip error sign flip error occur due linearity follows shor code correct arbitrary 1-qubit errors several proposals made storing error-correctable quantum information bosonic modes unlike two-level system oscillator infinitely many energy levels single physical system example cat code followed shortly gottesman-kitaev-preskill gkp states recently binomial code insight offered codes take advantage redundancy within single system rather duplicate many two-level qubits written fock basis simplest binomial encoding formula_68 subscript l indicates logically encoded state dominant error mechanism system stochastic application bosonic lowering operator formula_69 corresponding error states formula_70 formula_71 respectively since codewords involve even photon number error states involve odd photon number errors detected measuring photon number parity system general quantum code quantum channel formula_72 subspace formula_73 formula_74 state hilbert space exists another quantum channel formula_75 formula_76 formula_77 orthogonal projection onto formula_78 formula_75 known correction operation non-degenerate code one different elements set correctable errors produce linearly independent results applied elements code distinct set correctable errors produce orthogonal results code considered pure time researchers come several codes codes allow indeed quantum computations arbitrary length content threshold theorem found michael ben-or dorit aharonov asserts correct errors concatenate quantum codes css codes—i.e re-encode logical qubit code logarithmically many levels— provided error rate individual quantum gates certain threshold otherwise attempts measure syndrome correct errors would introduce new errors correct late 2004 estimates threshold indicate could high 1-3 provided sufficiently many qubits available several experimental realizations css-based codes first demonstration nmr qubits subsequently demonstrations made linear optics trapped ions superconducting transmon qubits error correcting codes also implemented one aimed correcting photon loss dominant error source photonic qubit schemes
|
Computer architecture
|
media control interface media control interface — mci short — high-level api developed microsoft ibm controlling multimedia peripherals connected microsoft windows os/2 computer cd-rom players audio controllers mci makes simple write program play wide variety media files even record sound passing commands strings uses relations described windows registries mci section file system.ini one advantage api mci commands transmitted programming language scripting language open script lingo aso example commands mcisendcommand mcisendstring mci interface phased favor directx apis first released 1995 media control interface consists 7 parts so-called mci devices e.g cd-rom vcd player play certain type files e.g avivideo plays .avi files cdaudio plays cd-da tracks among others mci devices also made available time play type media needs initialized correctly using mci commands commands subdivided categories full list mci commands found microsoft msdn library
|
Operating systems
|
layered service provider layered service provider lsp deprecated feature microsoft windows winsock 2 service provider interface spi layered service provider dll uses winsock apis attempt insert tcp/ip protocol stack stack layered service provider intercept modify inbound outbound internet traffic allows processing tcp/ip traffic taking place internet applications accessing internet web browser email client etc. example could used malware redirect web browers rogue websites block access sites like windows update alternatively computer security program could scan network traffic viruses threats winsock service provider interface spi api provides mechanism layering providers top winsock lsps available range useful purposes including parental controls web content filtering parental controls web filter windows vista lsp layering order providers kept winsock catalog unlike well-known winsock 2 api covered numerous books documentation samples winsock 2 spi relatively unexplored winsock 2 spi implemented network transport service providers namespace resolution service providers winsock 2 spi used extend existing transport service provider implementing layered service provider example quality service qos windows 98 windows 2000 implemented lsp tcp/ip protocol stack another use lsps would develop specialized url filtering software prevent web browsers accessing certain sites regardless browser installed desktop winsock 2 spi allows software developers create two different types service providers—transport namespace transport providers commonly referred protocol stacks services supply functions set connections transfer data exercise flow control error control namespace providers services associate addressing attributes network protocol one human-friendly names enable protocol-independent name resolution spi also allows develop two types transport service providers—base layered service providers base service providers implement actual details transport protocol setting connections transferring data exercising flow control error control layered service providers implement higher-level custom communication functions rely existing underlying base provider actual data exchange remote endpoint winsock 2 lsps implemented windows dlls single exported entry function wspstartup transport spi functions made accessible ws2_32.dll upper chain layered provider via lsp dispatch table lsps base providers strung together form protocol chain lsp dll registered using special lsp registrant instructs winsock 2 loading order lsps one lsp installed protocols intercept lsps work intercepting winsock 2 commands processed ws2_32.dll therefore modify commands drop command log data makes useful tool malware network filters network intercepters stream based sniffers sniffing network traffic lsp sometimes troublesome since anti-virus vendors typically flag activity malicious — network packet analyzer therefore better alternative capturing network traffic feature lsp winsock proxy sniffing allow traffic captured single application also enable traffic going localhost 127.0.0.1 sniffed windows two kinds lsp ifs non ifs lsp currently lsps market non ifs difference two lsps non ifs lsps modify socket handle non valid windows ifs handle therefore lsp must implement winsock 2 methods ifs lsps hand preserve socket handle allows lsp implement functions wants intercept ifs lsps much less performance impact non ifs lps limited fact inspect modify data receive path lsps deprecated since windows server 2012 systems include lsps pass windows logo checks windows 8 style metro apps use networking automatically bypass lsps windows filtering platform provides similar functionality compatible windows 8 style metro apps conventional desktop applications major issue lsps bugs lsp cause applications break example lsp returns wrong number bytes sent interface cause applications go infinite loop waiting network stack indicate data sent another major common issue lsps removed unregistered improperly lsp buggy would result corruption winsock catalog registry entire tcp/ip stack would break computer could longer access network lsp technology often exploited spyware adware programs order intercept communication across internet example malware may insert lsp network stack forward user traffic unauthorized external site data-mined find user interests bombard him/her targeted advertisements well spam e-mail malware lsp removed correctly older versions windows may left without working network connection potential loss network connectivity prevented windows xp service pack 2 windows server 2003 service pack 1 later windows operating systems winsock ability self-heal user uninstalls lsp installed lsps viewed using xp/vista windows defender software explorer using third-party utilities
|
Operating systems
|
cherrypal cherrypal california-based marketer chinese-manufactured consumer-oriented computers markets range models diversity cpu-types structures features operating systems commentators observed cherrypal arguably beat heralded much-better financed one laptop per child olpc project goal 100 laptop units physically small cherrypal unit general purchase 99 plus shipping 7 screen olpc provided child developing world 199 7.5 company business practices generated controversy antipathy vocally dissatisfied customers others marginally satisfied practices pertaining merchandise returns communication repeatedly faulted u.s better business bureau rating cherrypal f indicating bbb strongly questions company ’ reliability cherrypal claims commitment environmental concerns needs impoverished countries particular key sponsorship learning center ghana supports one laptop per teacher pilot program nigeria order company marketed c114 ppc-processor-based nettop cherrypal bing x86-based netbook cherrypal africa xburst-cpu-based netbook cherrypal asia arm-processor-based netbooks cherrypad america arm-processor-based tablet computer cherrypal c114 small light nettop computer using powerpc-processor freescale 5121e system-on-a-chip soc integrated main-board xubuntu operating system device launches firefox minefield web-browser abiword word-processor apps via icon double-click article register noted cherrypal producers asserted computer consume 2 watts power independent informal testing shown wattage consumption still low 6.9 watts booting cherrypal c114 rebadged version limepc d1 mini-desktop computer developed part broader freescale powerpc chip-based product line thtf shenzhen r center shown public 2008 ces las vegas january 2008 cherrypal bing slim x86-based netbook ships windows xp cherrypal 99 netbook africa aimed primarily developing world also available sale consumers according blog post max seybold device specs cherrypal web store kept intentionally vague africa built set design instead cherrypal either purchases pre-made netbook systems buys odd lots whatever inexpensive components available builds netbooks rebrands netbooks africas 99 computer named africa honor paajaf humanitarian services group based ghana west-africa seybold states resulting device minimum meet specs listed website could also exceed could also end arm mips x86-based cpu architecture depending chips available interview seybold stated africa meant sold computer traditional sense appliance provide internet access people could afford buy traditional computer said number government services unemployment disability encouraging access internet lack access becoming disability thing cherrypal promises 99 ability access internet cherrypal asia low cost arm-based netbook uses android os version 1.7 cherrypal america also known cherrypad android tablet based upon telechips tcc89xx arm11 processors cherrypal initially sold tablet promise upgrade android 2.2 november support android market market support officially removed tablet conform market requirements google also android 2.2 upgrade canceled instead cherrypal promises update android 2.3 hardware cherrypal america listed cherrypal comprises 800 mhz arm11 cpu telechips 256 mb ddr2 ram 2 gb flash memory 800x480 resistive touchscreen however user report arguing less powerful specifications according boot-log dumped via dmesg according various android news magazines cherrypal announced successor current cherrypad cherrypal founded max seybold based palo alto c114 following c120 desktop computers originally developed tsinghua tongfang thtf shenzhen r center engineering team led american electronics industry veterans jack campbell ryan quinn extended line handheld desktop tv-based pcs using freescale mpc5121e powerpc microprocessor shown ces 2008 thtf desktop product picked thereafter oem purchase cherrypal cherrypal marketers planned use firefox web-browser also user interface launch applications openoffice.org planned cherrypal would make use cloud computing applications storage would wholly part internet-based plans yet implemented company president asserted cloud green maraschino would launched february 2010 however known occurred
|
Distributed computing architecture
|
carrier-sense multiple access collision detection carrier-sense multiple access collision detection csma/cd media access control method used notably early ethernet technology local area networking uses carrier-sensing defer transmissions stations transmitting used combination collision detection transmitting station detects collisions sensing transmissions stations transmitting frame collision condition detected station stops transmitting frame transmits jam signal waits random time interval trying resend frame csma/cd modification pure carrier-sense multiple access csma csma/cd used improve csma performance terminating transmission soon collision detected thus shortening time required retry attempted following procedure used initiate transmission procedure complete frame transmitted successfully collision detected transmission following procedure used resolve detected collision procedure complete retransmission initiated retransmission aborted due numerous collisions methods collision detection media dependent shared electrical bus 10base5 10base2 collisions detected comparing transmitted data received data recognizing higher normal signal amplitude bus media carrier sensed receive channel transmitting triggers collision event repeaters hubs detect collisions propagate jam signals collision recovery procedure likened happens dinner party guests talk common medium air speaking guest politely waits current speaker finish two guests start speaking time stop wait short random periods time ethernet time measured microseconds hope choosing random period time guests choose time try speak thus avoiding another collision jam signal jamming signal signal carries 32-bit binary pattern sent data station inform stations collision must transmit maximum jam-time calculated follows maximum allowed diameter ethernet installation limited 232 bits makes round-trip-time 464 bits slot time ethernet 512 bits difference slot time round-trip-time 48 bits 6 bytes maximum jam-time turn means station noting collision occurred sending 4 6 byte long pattern composed 16 1-0 bit combinations note size jam signal clearly minimum allowed frame-size 64 bytes purpose ensure node may currently receiving frame receive jam signal place correct 32-bit mac crc causes receivers discard frame due crc error late collision type collision happens packet allowed protocol standard question 10 megabit shared medium ethernet collision error occurs first 512 bits data transmitted transmitting station late collision said occurred importantly late collisions re-sent nic unlike collisions occurring first 64 octets left upper layers protocol stack determine loss data correctly set csma/cd network link late collisions usual possible causes full-duplex/half-duplex mismatch exceeded ethernet cable length limits defective hardware incorrect cabling non-compliant number hubs network bad nic local collision collision occurs nic opposed wire nic detect local collisions without attempting send information utp cable local collision detected local segment station detects signal rx pair time sending tx pair since two signals different pairs characteristic change signal collisions recognized utp station operating half-duplex functional difference half full-duplex operation regard whether transmit receive pairs permitted used simultaneously channel capture effect phenomenon one user shared medium captures medium significant time period usually 16 frames users denied use medium effect first seen networks using csma/cd ethernet effect data-intense connection dominates multiple-access wireless channel happens ethernet links way nodes back link attempt re-access ethernet protocol communication collision happens two users medium try send time user waits random period time re-accessing link however user wait back random amount time proportional number times successively tried access link channel capture effect happens one user continues win link example user user b try access quiet link time since detect collision user waits random time 0 1 time units user b let say user chooses lower back-off time user begins use link b allows finish sending frame user still send user user b cause another data collision choose random back-off time 0 1 user b choose back-off time 0 3 – b second time colliding row chances win one continues likely win collision battles 16 collisions number tries user backs extended period time user captured channel ability one node capture entire medium decreased number nodes increases number nodes increases higher probability one nodes lower back-off time capturing node channel capture effect creates situation one station able transmit others continually backing thus leading situation short-term unfairness yet situation long-term fair every station opportunity capture medium one station done transmitting efficiency channel increased one node captured channel negative side effect capture effect would idle time created due stations backing one station finished transmitting medium large idle times present stations continually backing instances back-off occur long stations actually discard packets maximum attempt limits reached csma/cd used now-obsolete shared media ethernet variants 10base5 10base2 early versions twisted-pair ethernet used repeater hubs modern ethernet networks built switches full-duplex connections longer need use csma/cd ethernet segment collision domain isolated csma/cd still supported backwards compatibility half-duplex connections ieee 802.3 standard defines ethernet variants historical reasons still bore title carrier sense multiple access collision detection csma/cd access method physical layer specifications 802.3-2008 uses new name ieee standard ethernet
|
Internet protocols
|
comparison command shells command shell command line interface computer program operating system background execution allows shell run command background posix shells unix shells allow background execution using character end command powershell use codice_1 codice_2 commands completion features assist user typing commands command line looking suggesting matching words incomplete ones completion generally requested pressing completion key often key command name completion completion name command shells command program command path usually codice_3 builtin command function alias path completion completion path file relative absolute wildcard completion generalization path completion expression matches number files using supported syntax file matching variable completion completion name variable name environment variable shell variable bash zsh fish completion variable names powershell completions environment variable names shell variable names — within user-defined functions — parameter names command argument completion completion specific command arguments two types arguments named positional named arguments often called options identified name letter preceding value whereas positional arguments consist value shells allow completion argument names support completing values bash zsh fish offer parameter name completion definition external command distributed separate completion definition file command parameter name/value completions shells assume path/filename completion completion defined command completion set suggest completions calling shell function fish shell additionally supports parsing man pages extract parameter information used improve completions/suggestions powershell types commands cmdlets functions script files inherently expose data names types valid value ranges/lists argument metadata used powershell automatically support argument name value completion built-in commands/functions user-defined commands/functions well script files individual cmdlets also define dynamic completion argument values completion values computed dynamically running system user shell may find he/she typing something similar user typed shell supports command history user call previous command line editor edit issuing shells support completion may also able directly complete command command history given partial/initial part previous command modern shells support command history shells support command history general also support completion history rather recalling commands history addition plain command text powershell also records execution start- end time execution status command history mandatory arguments/parameters arguments/parameters must assigned value upon invocation command function script file shell determine ahead invocation missing mandatory values assist interactive user prompting values instead letting command fail shell prompt missing values allow author script command function mark parameter mandatory instead creating script code either prompt missing values determining run interactively fail message powershell allows commands functions scripts define arguments/parameters mandatory shell determines prior invocation mandatory arguments/parameters bound prompt user value actual invocation automatic suggestions shell monitors interactive user typing displays context-relevant suggestions without interrupting typing instead user explicitly requesting completion powershell integrated scripting environment use discoverable metadata provide intellisense i.e suggestions automatically pops user types addition user explicitly requests completion lists pressing e.g shell may record locations user used current locations allow fast switching location/directory history one uses zsh directory stack record directory history particular auto_pushd option advanced cd arguments completion used purpose powershell allows multiple named stacks used locations directories pushed onto/popped current stack named stack stack become current default stack unlike shells powershell location concept allow location stacks hold file system locations well location types like e.g active directory organizational units/groups sql server databases/tables/objects internet information server applications/sites/virtual directories 4dos take command console record history current directories allows user switch directory history using popup window directory name used directly command implicitly changes current location directory must distinguished unrelated load drive feature supported concurrent dos multiuser dos system manager real/32 drive letter l implicitly updated point load path loaded application thereby allowing applications refer files residing load directory standardized drive letter instead absolute path command line match command arguments directly spell checking automatically correct common typing mistakes case sensitivity missing letters two approaches shell either suggest probable corrections upon command invocation happen earlier part completion autosuggestion tcsh zsh shells feature optional spell checking/correction upon command invocation fish autocorrection upon completion autosuggestion feature therefore way typing whole command pressing enter whereas extensive use tab right-arrow keys makes shell mostly case insensitive psreadline powershell module shipped version 5.0 provides option specify commandvalidationhandler scriptblock runs submitting command allows custom correcting commonly mistyped commands verification actually running command integrated environment integration command-line interface editors typically multiple documents help system possibly debugging tools take command console tcc comes integrated environment command line pane file explorer editor batch debugger powershell ise includes command line pane support integrated command line copy-paste multiple document editors source-level debugging help pane command explorer pane scripting interface allowing scripts/modules manipulate menus add-ons etc ise menus windows shortcuts addons customizable scripts snippets small regions reusable script code snippets often used save keystrokes assist user common scripting patterns many text editors support snippets scripting either built-in functionality plugins powershell supports snippets integrated scripting environment ise using shell script prompt interactive user value shell script present interactive user list choices shell script job report progress long running tasks interactive user unix/linux systems may offer tools support using progress indicators scripts standalone-commands program pv integrated features shells however powershell built-in command api functions used authoring commands writing/updating progress bar progress bar messages sent separates regular command output progress bar always displayed ultimate interactive users console regardless whether progress messages originates interactive script background job remote session output command execution displayed table/grid interactively sorted filtered and/or otherwise manipulated command execution ends powershell out-gridview cmdlet displays data interactive window interactive sorting filtering jp software command-line processors provide user-configurable colorization file directory names directory listings based file extension and/or attributes optionally defined colordir environment variable unix/linux shells feature ls command terminal command line processors dos plus multiuser dos real/32 versions dr-dos support number optional environment variables define escape sequences allowing control text highlighting reversion colorization display print purposes commands like type mentioned command line processors support defined sequences emitted filenames typical sequence would \033 1m conjunction ansi.sys \033p ascii terminal \016 ibm esc/p printer likewise typical sequences would \033 0m \033q \024 respectively variables header footer supported command.com dr-dos 7.02 higher define sequences emitted text blocks order control text highlighting pagination formatting options unix/linux shells feature terminal independent project offers syntax highlighting add-on z shell zsh part shell however powershell provides customizable syntax highlighting command line psreadline module module used powershell v3.0+ included v5.0 additionally loaded default command line host powershell.exe v5.0 powershell ise also includes syntax highlighting command line well script pane take command console tcc offers syntax highlighting integrated environment 4dos 4os2 4nt take command console powershell powershell ise looks context-sensitive help information pressed zsh provides various forms configurable context-sensitive help part run-help widget _complete_help command completion options commands command builder guided dialog assists user filling command powershell command builder available powershell ise displayed separately show-command cmdlet anticipation given running application may accept keyboard input user shell instructs shell generate sequence simulated keystrokes application interpret keyboard input interactive user sending keystroke sequences user may able direct application perform actions would impossible achieve input redirection would otherwise require interactive user example application acts keystrokes redirected distinguishes normal extended keys flushes queue accepting new input startup certain conditions read standard input keystroke stacking typically also provides means control timing simulated keys sent delay new keys queue flushed etc also allows simulate keys present keyboard corresponding keys physically exist different keyboard layout used therefore would impossible type user shell scripts need query user sensitive information passwords private digital keys pin codes confidential information sensitive input echoed back screen/input device could gleaned unauthorized persons plaintext memory representation sensitive information also avoided could allow information compromised e.g. swap files core dumps etc shells bash zsh powershell offer specific feature shells offer specific feature may still able turn echoing means shells executing unix/linux operating system use stty external command switch off/on echoing input characters addition echoing back characters powershell -assecurestring option also encrypts input character-by-character input process ensuring string never represented unencrypted memory could compromised memory dumps scanning transcription etc script reads password environment variable memory plain text thus may accessed via core dump also process environment may accessible processes started script powershell work encrypted string variables/parameters encrypted variables ensure values inadvertently disclosed e.g transcripts echo'ing logfiles memory crash dumps even malicious memory scanning powershell also supports saving encrypted strings text files protected key owned current user operating systems define execute permission granted users/groups file unix systems execute permission controls access invoking file program applies executables scripts permission enforced program loader obligation needed invoking program invoked program enforcing execute permission also goes shells interpreter programs behaviour mandated posix c library used interfacing kernel posix specifies codice_4 family functions shall fail eaccess permission denied file denies execution permission see execute permission applies script run directly script invoked argument interpreting shell executed regardless whether user holds execute permission script although windows also specifies execute permission none windows-specific shells block script execution permission granted shells block scripts determined untrustworthy refuse run scripts mandated system administrator powershell set block execution scripts marked obtained unknown/untrusted origin e.g internet internet facing applications web browsers im clients mail readers etc mark files downloaded internet origin zone alternate data stream understood powershell script/code signing policies used ensure operations department run approved scripts/code reviewed signed trusted reviewer/approver signing regimes also protects tampering script sent vendor client client use signing ensure script tampered transit script indeed originates vendor attacker trying social engineer operator running attack script powershell set allow execution otherwise blocked scripts e.g originating untrusted zone script digitally signed using trusted digital certificate company may want enforce execution restriction globally within company and/or certain parts company may want set policy running signed scripts allow certain parts company set policies zoned restrictions powershell allows script blocking policies enforced multiple levels local machine current user etc higher level policy overrides lower level policy e.g policy defined local machine place users local machine left undefined higher level defined lower levels several shells started configured start mode limited set commands actions available user security boundary command accessing resource blocked rather resource nevertheless typically used restrict users actions logging restricted mode part posix specification shells linux/unix shells support mode several built-in commands disabled external commands certain directory invoked powershell supports restricted modes session configuration files session configurations session configuration file define visible available cmdlets aliases functions path providers scripts invoke scripts security risk potentially execute foreign code context user launched initial script scripts usually designed exclusively include scripts known safe locations instances e.g offering user way configure environment loading localized messages script may need include scripts/files one way address risk shell offer safe subset commands executed included script powershell data sections contain constants expressions using restricted subset operators commands powershell data sections used e.g localized strings needs read external source protecting unwanted side effects
|
Operating systems
|
carrier system carrier system telecommunications system transmits information voice signals telephone call video signals television modulation one multiple carrier signals principal voice frequency data rate carrier systems typically transmit multiple channels communication simultaneously shared medium using various forms multiplexing prominent multiplexing methods carrier signal time-division multiplexing tdm frequency-division multiplexing fdm cable television system example frequency-division multiplexing many television programs carried simultaneously coaxial cable sending different frequency multiple layers multiplexing may ultimately performed upon given input signal example public switched telephone network many telephone calls sent shared trunk lines time-division multiplexing long distance calls several channels may sent communications satellite link frequency-division multiplexing given receiving node specific channels may demultiplexed individually purpose carrier systems save money carrying traffic less infrastructure 19th century telephone systems operating baseband could carry one telephone call wire hence routes heavy traffic needed many wires 1920s frequency-division multiplexing could carry several circuits balanced wires 1930s l-carrier similar systems carried hundreds calls time coaxial cables capacity systems increased middle century 1950s researchers began take seriously possibility saving money terminal equipment using time-division multiplexing work led t-carrier similar digital systems local use due shorter repeater spacings required digital systems long-distance still used fdm late 1970s optical fiber improved point digital connections became cheapest ones distances short long end century analog connections within telephone exchanges became rare
|
Internet protocols
|
rockchip rockchip fuzhou rockchip electronics co. ltd. chinese fabless semiconductor company based fuzhou fujian province rockchip founded 2001 offices shanghai beijing shenzhen hangzhou hong kong designs system chip soc products using arm architecture licensed arm holdings majority projects rockchip ranked one top50 fabless company ic suppliers worldwide company established cooperation google microsoft intel 27 may 2014 intel announced agreement rockchip adopt intel architecture entry-level tablets rockchip supplier socs chinese white-box tablet manufacturers well supplying oems asus hp samsung toshiba market socs tablets rockchip faces competition allwinner technology mediatek intel actions semiconductor spreadtrum leadcore technology samsung semiconductor qualcomm broadcom via technologies amlogic establishing position early developing chinese tablet soc market 2012 faced challenge allwinner 2012 rockchip shipped 10.5 million tablet processors compared 27.5 million allwinner however q3 2013 rockchip forecast ship 6 million tablet-use application processors china compared 7 million allwinner mainly shipped single-core products rockchip reported number one supplier tablet-use application processors china q4 2013 q1 2014 q2 2014 chinese soc suppliers cellular baseband technology disadvantage compared companies mediatek also supply smartphone market white-box tablet makers increasingly add phone cellular data functionality products intel corporation made investments tablet processor market heavily subsidizing entry low-cost tablet market 2014 may 2014 intel announced agreement rockchip jointly deliver intel-branded mobile soc platform based intel atom processor 3g modem technology terms agreement two companies deliver intel-branded mobile soc platform quad-core platform based intel atom processor core integrated intel 3g modem technology expected available first half 2015 intel rockchip sell new part oems odms primarily company existing customer base october 2014 rockchip already offering intel xmm 6321 low-end smartphones two chips dual-core application processor either intel processor cores arm cortex-a5 cores integrated modem xg632 integrated rf chip ag620 originates cellular chip division infineon technologies intel acquired time ago application processor may also originate infineon intel rockchip earlier targeted smartphone space material way
|
Computer architecture
|
sio software sio serial port driver package os/2 written raymond l. gwinn designed improve performance os/2 default serial drivers also improve compatibility sio contains virtualized fossil vx00 driver loaded provide fossil support dos based communications software sio later added ability create virtualized com ports combined included program vmodem allows incoming telnet connections directed toward virtualized com port older communications software also able call telnet sites possible due custom set commands allow users pass hostname vmodem software sio included vmodem software became popular among bulletin board system operators due incoming telnet feature well drastic speed improvements telnet solutions time
|
Operating systems
|
memory ballooning memory ballooning technique used eliminate need overprovision host memory used virtual machine vm implement virtual machine kernel implements balloon driver allocates unused memory within vm address space reserved memory pool balloon unavailable processes vm however rather reserved uses within vm physical memory mapped pages within vm actually unmapped vm host operating system hypervisor making available uses host machine depending amount memory required vm size balloon may increased decreased dynamically mapping unmapping physical memory required vm
|
Operating systems
|
apollo vp3 apollo vp3 alias eteq 6628 x86 based socket 7 chipset manufactured via technologies launched 1997 time apollo vp3 high performance cost effective energy efficient chipset offered agp support socket 7 processors supported moment intel sis ali chipsets november 1997 fic released motherboard pa-2012 uses apollo vp3 agp bus first socket 7 motherboard supporting agp apollo vp3 supports 32 bits socket 7 cpu-s like pentium pentium mmx amd k5 amd k6 cyrix 6x86 winchip c2 c6 cpu-s uses vt82c597 vt82c597at baby atx motherboards northbridge controller chip ac97 compliant vt82c586b southbridge chip acpi power management system vp3 64 bits memory bus 32 bits 33 mhz pci 32 bits 66 mhz agp 2x sideband addressing 133 mhz signalling 533 mb/s transfer capability interfaces uses integrated 10-bits tag comparator supports 2 mb pipelined burst synchronous sram cache memory 1 gb ecc cachable ram memory memory controller supports 8 memory pages banks interleaving mode flexible row column addresses concurrent dram writeback read around write capability burst read write operations etc details see officially supported speeds memory bus 50 60 66 mhz numerous implemented motherboards vp3 also 75 even 83 mhz bus speed capability vt82c597 northbridge supports six memory banks dram-s dimm-s 1gb total size memory controller supports standard fast page mode fpm dram edo-dram synchronous dram sdram also sdram-ii double data rate ddr flexible mixed configuration synchronous dram interface allows zero wait state bursting dram data buffers 66 mhz six memory banks dram used arbitrary mixture 1mb 2mb 4mb 8mb 16mbxn dram dimm modules memory controller 3,3 v 5 v tolerant interface vt82c586b includes udma-33 eide usb keyboard/ps2-mouse interfaces chip rtc plus 256 kb cmos anandtech described apollo vp3 combination via apollo vp2 intel 440lx chipsets apollo vp3 quite shortly replaced via apollo mvp3 chipset offers faster 100 mhz memory bus capability asynchronous memory bus supports somewhat less amount cachable memory area system dram four memory banks lack 100 mhz bus support needed newer amd cyrix etc. super socket 7 processors pushed via drop vp3 production majority motherboards basis apollo vp3 chipset implemented 512 kb l2 cache memory single 32kb tag-ram chip 2 rarely 3 168-pin dimm slots plus 2 rarely 4 72-pin simm slots agp slot 2-4 pci slots 2-3 isa slots extremes fic pa-2012 shuttle hot-595 1024 kb 512 kb l2 cache memory three 168-pin dimm slots 1 agp 4 pci 2 isa tyan trinity atx s1592s three 168-pin dimm slots plus four 72-pin so-dimm slots 1 agp 4 pci 3 isa apollo vp3 chipset sold soyo also name eteq 6628 chipset
|
Computer architecture
|
gunfright gunfright arcade adventure video game developed ultimate play game published u.s. gold first released zx spectrum 1985 ported amstrad cpc msx later year game player takes role sheriff town black rock tasked eliminating outlaws scattered throughout settlement game developed directly nightshade re-uses latter game filmation ii game engine allows images rendered without overlapping game received mostly positive reviews upon release praise directed graphics presentation criticism directed game similarity nightshade later included rare replay rare 2015 xbox one retrospective compilation game presented isometric format set fictional town black rock player takes role sheriff quickdraw main objective game track kill gang outlaws hiding town game begins first-person perspective targeting minigame vertically scrolling bags money shot using crosshairs shooting bags give player initial sums money used purchase ammunition game quickdraw must locate wanted outlaws one one outlaw found shot shooting outlaw kill initiates duel game shifts first-person targeting minigame time player must shoot rapidly moving outlaw quickly possible player either wait outlaw draw take initiative shoot first make bandit draw weapon well player successfully shoots outlaw bounty paid increasing every round new outlaw enters town gameplay players often encounter helpful residents point way outlaws residents need protected gameplay player pay fine shot either bandits sheriff quickdraw outlaws mounted horseback meaning player may saddle imaginary horse pursue game developed isometric projection game engine known filmation ii used previously ultimate 1985 zx spectrum game nightshade filmation engine created stamper brothers portray 3d imagery filmation ii used image masking technique drew filled holes background allowing game create composite structures pixelated drawings without visual overlay despite limitations platforms zx spectrum offered gunfright initially released zx spectrum 1985 last game developed direct involvement stamper brothers realising graphical limits platforms zx spectrum pushed future projects blackwyche dragon skulle handed designer brothers dave bob thomas often uncredited work gunfright along knight lore alien 8 nightshade re-released msx 1986 gunfright sabre wulf ported amstrad cpc later year gunfright later included august 2015 xbox one compilation 30 rare titles rare replay game received mostly positive reviews upon release reviewers writing crash praised game graphics highly detailed colourful stated game visually similar ultimate immediately previous game nightshade gwyn hughes sinclair thought graphics best aspect game despite similarly comparing nightshade hughes also praised game smooth animation techniques used portray western town reviewer cvg suggested game style gameplay mix nightshade nintendo duck hunt reviewing msx version reviewer computer gamer praised game plot complimentary way game able separate ultimate previous game used filmation engine reviewers writing crash praised gameplay stating game element considerably developed several different stages highly addictive writers cvg criticised gameplay noting found difficult distinguish outlaws male inhabitants town also noted absence puzzle elements considered unusual ultimate game bill bennett computer similarly considered omission puzzle elements unusual welcomed witty change genre previous dungeon-themed video games
|
Computer architecture
|
cell relay computer networking cell relay refers method statistically multiplexing small fixed-length packets called cells transport data computers kinds network equipment unreliable connection-oriented packet switched data communications protocol cell relay transmission rates usually 56 kbit/s several gigabits per second atm particularly popular form cell relay commonly used home dsl connections often runs 128 kbit/s 1.544 mbit/s ds1 high-speed backbone connections oc-3 faster cell relay protocols neither flow control error correction capability information-content independent correspond layers one two osi reference model cell relay used delay- jitter-sensitive traffic voice video cell relay systems break variable-length user packets groups fixed-length cells add addressing verification information frame length fixed networking hardware based time delay user packet-length considerations one user data message may segmented many cells cell relay systems may also carry bitstream-based data pdh traffic breaking streams cells lightweight synchronization clock recovery shim thus cell relay systems may potentially carry combination stream-based packet-based data form statistical time division multiplexing cell relay implementation fast packet-switching technology used connection-oriented broadband integrated services digital networks b-isdn better-known supporting technology atm connectionless ieee 802.6 switched multi-megabit data service smds time information transmitted switch basically sends data units connections ’ negotiated like circuit switching channels ’ allocated channels exist atm condition adequate amount bandwidth maintain indefinite transmissions facility cell relay utilizes data cells persistent size frames comparable data packets however contrast cells may fluctuate size based circumstances type technology secure reason procedures support error handling data recovery per se delicate significant transmissions may perhaps transported faster via fixed-sized cells simpler transmit compared variable-sized frames packets cell relay extremely reliable transporting vital data switching devices give precise method cells endpoint address embedded cell example cell relay atm prevalent form utilized transfer cell fixed size 53 bytes
|
Internet protocols
|
world database protected areas world database protected areas wdpa largest assembly data world terrestrial marine protected areas containing 200,000 protected areas october 2017 records covering 245 countries territories throughout world wdpa joint venture united nations environment programme world conservation monitoring centre unep-wcmc international union conservation nature iucn world commission protected areas wcpa data wdpa collected international convention secretariats governments collaborating ngos role custodian allocated protected areas programme unep-wcmc based cambridge uk hosted database since creation 1981 wdpa delivers invaluable information decision-makers around world particularly terms measuring extent effectiveness protected areas indicator meeting global biodiversity targets october 2010 unep-wcmc launched social media-based website protected planet allows users interact improve data currently recorded world database protected areas. br wdpa uses iucn definition protected area main criteria entries included database database contains comprehensive information different types protected areas ranging strictly protected conservation purposes sustainable use natural resources allowed includes government co-managed private community-managed areas iucn world commission protected areas gives international guidance categorisation protected areas protected area management categories categories recognised worldwide facilitate global system defining recording protected areas within wpda iucn management category protected area listed one assigned/reported part information protected area data held wdpa made 'attribute 'spatial information attribute data refers characteristics protected area name reported area designation type spatial data provided form geographical information system gis electronic maps often referred shapefiles files provide information location latitude longitude spatial extent protected area either midpoint location polygon shows boundaries protected area gives indication size shape form data takes protected planet data wdpa available public use worldwide wdpa development team unep-wcmc formal agreement global biodiversity information facility gbif integrate network species occurrence data shapefiles protected areas wdpa assists governmental non-governmental private organisations visualise density species within protected area protected areas within wdpa assigned national international designation many protected areas fall category nationally designated designated within country national territory including maritime economic exclusive zone using appropriate legislation agreements internationally designated sites primarily significant environmental cultural natural value protected irrespective territory located areas often recognized preserved protected international treaty convention cases internationally recognized site may nationally designated well common international conventions protected areas designated unesco seeks encourage identification protection preservation cultural natural heritage around world considered outstanding value humanity embodied international treaty called convention concerning protection world cultural natural heritage adopted unesco 1972 man biosphere programme mab proposes interdisciplinary research agenda capacity building aim improve relationship people environment globally since launch 1970 mab concentrated development world network biosphere reserves wnbr biosphere reserve concept developed initially 1974 substantially revised 1995 adoption unesco general conference statutory framework seville strategy biosphere reserves convention wetlands intergovernmental treaty adopted 2 february 1971 iranian city ramsar southern shore caspian sea convention entered force 1975 mission adopted parties 1999 refined 2002 “ conservation wise use wetlands local regional national actions international cooperation contribution towards achieving sustainable development throughout world ” comprehensive global inventory world protected areas wdpa key resource managing researching protected areas order conserve world living resources protected planet information wdpa openly available numerous formats used within biological science community also individuals government agencies non-profit organisations private sector businesses wdpa used predominantly following purposes protected planet developed database internet portal wdpa intention user-friendly enabling users visualise explore measure protected areas interactive maps summary statistics tools aim development reduce burden data gathering make collection protected areas efficient whereas wdpa previously reliant assistance numerous national agencies hindered incomplete information protected area sites constant need updates protected planet launched convention biological diversity 10th conference parties nagoya japan october 2010 largely funded investment private sector acts new-age infrastructure downloading protected area data registered users hosted multiple servers across globe registered data providers range single individual large global organisation web technology utilised improve searching options search results displayed generate better data downloads produce standardized format minimum fields requiring completion fact protected planet open academics scientists students researchers park managers local communities enables use online tools generate date statistics protected areas employ feedback users make improvements using social networking tools protected planet allows wdpa displayed alongside additional resources photos points interest nearby protected areas interoperability discovery information wikipedia global biodiversity information facility gbif panoramio photo services category science technology cambridgeshire category scientific databases
|
Databases
|
cloud-computing comparison following comparison cloud-computing software providers paas providers run iaas providers means provider paas iaas
|
Distributed computing architecture
|
macscan macscan anti-malware utility apple mac os x developed securemac aimed removing malware including spyware trojan horses keystroke loggers tracking cookies first anti-spyware program released mac os x addition application scans remote administration programs like apple remote desktop allowing users verify programs installed authorization unlike anti-malware applications available mac os x systems macscan scans exclusively malware affects macs opposed scanning forms known threats would include windows malware given considerably less mac-based malware windows-based malware macscan definition files smaller optimized full version macscan available shareware 30-day trial available free developer website download macscan started discussion securemac.com forums developed response specific user concerns malware securemac developed keep mac platform secure scanning viruses malware addition selling flagship product securemac releases special-purpose removal utilities public free charge threat might compromise broader platform releases included utilities remove particular threat designed remove free
|
Computer security
|
file exchange protocol file exchange protocol fxp fxsp method data transfer uses ftp transfer data one remote server another inter-server without routing data client connection conventional ftp involves single server single client data transmission done two fxp session client maintains standard ftp connection two servers direct either server connect initiate data transfer advantage using fxp ftp evident high-bandwidth server demands resources another high-bandwidth server low-bandwidth client network administrator working away location authority access resources servers enabling fxp support make server vulnerable exploit known ftp bounce result ftp server software often fxp disabled default sites restricted ip addresses trusted sites limit risk ftp servers glftpd cuftpd raidenftpd drftpd wzdftpd support negotiation secure data channel two servers using either ftp protocol extension commands cpsv sscn normally works client issuing cpsv lieu pasv command—or sending sscn prior pasv transfers—which instructs server create either ssl tls connection however methods—cpsv sscn—may susceptible man-in-the-middle attacks two ftp servers verify ssl certificates sscn first introduced raidenftpd smartftp 2003 widely adopted although fxp often considered distinct protocol fact merely extension ftp protocol specified protocol standardized subset rfc 959 ietf
|
Internet protocols
|
donald knuth donald ervin knuth born january 10 1938 american computer scientist mathematician professor emeritus stanford university 1974 recipient acm turing award informally considered nobel prize computer science author multi-volume work art computer programming contributed development rigorous analysis computational complexity algorithms systematized formal mathematical techniques process also popularized asymptotic notation addition fundamental contributions several branches theoretical computer science knuth creator tex computer typesetting system related metafont font definition language rendering system computer modern family typefaces writer scholar knuth created web cweb computer programming systems designed encourage facilitate literate programming designed mix/mmix instruction set architectures knuth strongly opposes granting software patents expressed opinion united states patent trademark office european patent organisation knuth born milwaukee wisconsin german-americans ervin henry knuth louise marie bohning father two jobs running small printing company teaching bookkeeping milwaukee lutheran high school donald student milwaukee lutheran high school received academic accolades especially ingenious ways thought solving problems example eighth grade entered contest find number words letters ziegler giant bar could rearranged create although judges 2,500 words list donald found 4,500 words winning contest prizes school received new television enough candy bars schoolmates eat 1956 knuth received scholarship case institute technology part case western reserve university cleveland ohio also joined beta nu chapter theta chi fraternity studying physics case institute technology knuth introduced ibm 650 one early mainframes reading computer manual knuth decided rewrite assembly compiler code machine used school believed could better 1958 knuth created program help school basketball team win games assigned values players order gauge probability getting points novel approach newsweek cbs evening news later reported knuth one founding editors case institute engineering science review national award best technical magazine 1959 switched physics mathematics 1960 received bachelor science degree simultaneously given master science degree special award faculty considered work exceptionally outstanding 1963 mathematician marshall hall adviser earned phd mathematics california institute technology receiving phd knuth joined caltech faculty assistant professor accepted commission write book computer programming language compilers working project knuth decided could adequately treat topic without first developing fundamental theory computer programming became art computer programming originally planned publish single book knuth developed outline book concluded required six volumes seven thoroughly cover subject published first volume 1968 publishing first volume art computer programming knuth left caltech accept employment institute defense analyses communications research division situated princeton university campus performing mathematical research cryptography support national security agency knuth left position join stanford university faculty 1969 fletcher jones professor computer science emeritus knuth writer well computer scientist knuth called father analysis algorithms 1970s knuth described computer science totally new field real identity standard available publications high lot papers coming quite simply wrong ... one motivations put straight story badly told 2011 first three volumes part one volume four series published concrete mathematics foundation computer science 2nd ed. originated expansion mathematical preliminaries section volume 1 taocp also published bill gates praised difficulty subject matter art computer programming stating think 're really good programmer ... definitely send résumé read whole thing knuth also author surreal numbers mathematical novelette john conway set theory construction alternate system numbers instead simply explaining subject book seeks show development mathematics knuth wanted book prepare students original creative research 1995 knuth wrote foreword book a=b marko petkovšek herbert wilf doron zeilberger knuth also occasional contributor language puzzles knuth also delved recreational mathematics contributed articles journal recreational mathematics beginning 1960s acknowledged major contributor joseph madachy mathematics vacation knuth also appeared number numberphile computerphile videos youtube discussed topics writing surreal numbers n't use email addition writings computer science knuth lutheran also author 3:16 bible texts illuminated examines bible process systematic sampling namely analysis chapter 3 verse 16 book verse accompanied rendering calligraphic art contributed group calligraphers leadership hermann zapf subsequently invited give set lectures 3:16 project resulting another book things computer scientist rarely talks published lectures god computer science member academic scientific community knuth strongly opposed policy granting software patents trivial solutions obvious expressed nuanced views nontrivial solutions interior-point method linear programming expressed disagreement directly united states patent trademark office european patent organisation knuth gives informal lectures times year stanford university titled computer musings visiting professor oxford university department computer science united kingdom 2017 honorary fellow magdalen college 1970s publishers taocp abandoned monotype favor phototypesetting knuth became frustrated inability latter system approach quality previous volumes typeset using older system took time work digital typesetting created tex metafont developing tex knuth created new methodology programming called literate programming believed programmers think programs works literature instead imagining main task instruct computer let us concentrate rather explaining human beings want computer knuth embodied idea literate programming web system web source used weave tex file tangle pascal source file turn produce readable description program executable binary respectively later iteration system cweb replaces pascal c. knuth used web program tex metafont published programs books texbook originally published 1984 metafontbook originally published 1986 around time latex now-widely-adopted macro package based tex first developed leslie lamport later published first user manual 1986 donald knuth married nancy jill carter 24 june 1961 graduate student california institute technology two children john martin knuth jennifer sierra knuth knuth chinese name gao dena 1977 given name frances yao shortly making 3-week trip china 1980 volume art computer programming knuth explains embraced chinese name wanted known growing numbers computer programmers china time 1989 chinese name placed atop journal computer science technology header knuth says makes feel close chinese people although speak language 2006 knuth diagnosed prostate cancer underwent surgery december year stated little bit radiation therapy ... precaution prognosis looks pretty good reported video autobiography knuth used pay finder fee 2.56 typographical errors mistakes discovered books 256 pennies one hexadecimal dollar 0.32 valuable suggestions according article massachusetts institute technology technology review knuth reward checks among computerdom prized trophies knuth stop sending real checks 2008 due bank fraud instead gives error finder certificate deposit publicly listed balance fictitious bank san serriffe warned correspondent beware bugs code proved correct tried knuth published first scientific article school magazine 1957 title potrzebie system weights measures defined fundamental unit length thickness mad 26 named fundamental unit force whatmeworry mad published article issue 33 june 1957 demonstrate concept recursion knuth intentionally referred circular definition definition circular index art computer programming volume 1 preface concrete mathematics following paragraph tug 2010 conference knuth announced satirical xml-based successor tex titled itex performed bell ringing would support features arbitrarily scaled irrational units 3d printing input seismographs heart monitors animation stereophonic sound 1971 knuth recipient first acm grace murray hopper award received various awards including turing award national medal science john von neumann medal kyoto prize knuth elected distinguished fellow british computer society dfbcs 1980 recognition knuth contributions field computer science 1990 awarded one-of-a-kind academic title professor art computer programming since revised professor emeritus art computer programming knuth elected national academy sciences 1975 1992 became associate french academy sciences also year retired regular research teaching stanford university order finish art computer programming elected foreign member royal society formemrs 2003 knuth elected fellow first class fellows society industrial applied mathematics 2009 outstanding contributions mathematics member norwegian academy science letters 2012 became fellow american mathematical society awards honors include short list publications include art computer programming computers typesetting books hardcover unless otherwise noted books collected papers books
|
Programming language topics
|
robust random early detection robust random early detection rred queueing disclipine network scheduler existing random early detection red algorithm variants found vulnerable emerging attacks especially low-rate denial-of-service attacks ldos experiments confirmed existing red-like algorithms notably vulnerable ldos attacks due oscillating tcp queue size caused attacks robust red rred algorithm proposed improve tcp throughput ldos attacks basic idea behind rred detect filter attack packets normal red algorithm applied incoming flows rred algorithm significantly improve performance tcp low-rate denial-of-service attacks detection filter block added front regular red block router basic idea behind rred detect filter ldos attack packets incoming flows feed red algorithm distinguish attacking packet normal tcp packets critical rred design within benign tcp flow sender delay sending new packets loss detected e.g. packet dropped consequently packet suspected attacking packet sent within short-range packet dropped basic idea detection algorithm robust red rred nowiki rred-enque pkt 01 f←rred-flowhash pkt 02 tmax←max flow f .t1 t2 03 pkt.arrivaltime within tmax tmax+t* 04 reduce local indicator 1 bin corresponding f 05 else 06 increase local indicator 1 bin f 07 flow f .i←maximum local indicators bins f 08 flow f .i =0 09 red-enque pkt //pass pkt red block 10 red drops pkt 11 t2←pkt.arrivaltime 12 else 13 flow f .t1←pkt.arrivaltime 14 drop pkt 15 return simulation code rred algorithm published active queue management denial-of-service attack aqm dos simulation platform aqm dos simulation platform able simulate variety dos attacks distributed dos spoofing dos low-rate dos etc active queue management aqm algorithms red rred sfb etc. automatically calculates records average throughput normal tcp flows dos attacks facilitate analysis impact dos attacks normal tcp flows aqm algorithms
|
Computer security
|
dark mail alliance dark mail alliance organization dedicated creating email protocol architecture end-to-end encryption october 2013 silent circle lavabit announced project create secure alternative email began fundraising effort dark mail alliance team consists phil zimmermann jon callas mike janke ladar levison dark internet mail environment dime aims secure communication platform asynchronous messaging across internet presented ladar levison stephen watt def con multiple revisions dime specifications latest revision presented preliminary draft magma reference mime server implementation supports server side encryption simple mail transfer protocol smtp post office protocol pop internet message access protocol imap hypertext transfer protocol http volcano thunderbird fork dime support
|
Computer security
|
windows security log security log microsoft windows log contains records login/logout activity security-related events specified system audit policy auditing allows administrators configure windows record operating system activity security log security log one three logs viewable event viewer local security authority subsystem service writes events log security log one primary tools used administrators detect investigate attempted successful unauthorized activity troubleshoot problems microsoft describes best last defense log audit policies govern also favorite targets hackers rogue system administrators seeking cover tracks committing unauthorized activity audit policy set record logins successful login results user user name computer name logged well user name logging depending version windows method login ip address may may recorded windows 2000 web server instance log ip addresses successful logins windows server 2003 includes capability categories events logged sheer number loggable events means security log analysis time-consuming task third-party utilities developed help identify suspicious trends also possible filter log using customized criteria administrators allowed view clear log way separate rights view clear log addition administrator use winzapper delete specific events log reason administrator account compromised event history contained security log unreliable defense set remote log server services shut allowing console access log approaches maximum size either overwrite old events stop logging new events makes susceptible attacks intruder flood log generating large number new events partial defense increase maximum log size greater number events required flood log possible set log overwrite old events chris benton notes problem nt really bad habit crashing logs become full randy franklin smith ultimate windows security points given ability administrators manipulate security log cover unauthorized activity separation duty operations security-monitoring staff combined frequent backups log server accessible latter improve security another way defeat security log would user log administrator change auditing policies stop logging unauthorized activity intends carry policy change could logged depending audit policy change setting event could deleted log using winzapper point onward activity would generate trail security log microsoft notes possible detect attempts elude security monitoring solution techniques challenging many events occur attempt cover tracks intrusive activity events occur regularly typical business network benton points one way preventing successful attacks security obscurity keeping department security systems practices confidential helps prevent users formulating ways cover tracks users aware log copied remote log server :00 every hour instance may take measures defeat system attacking :10 deleting relevant log events top next hour log manipulation needed attacks simply aware security log works enough take precautions detection instance user wanting log fellow employee account corporate network might wait hours gain unobserved physical access computer cubicle surreptitiously use hardware keylogger obtain password later log user account terminal services wi-fi hotspot whose ip address traced back intruder log cleared event viewer one log entry immediately created freshly cleared log noting time cleared admin cleared information starting point investigation suspicious activity addition windows security log administrators check internet connection firewall security log clues theoretically possible write false events log microsoft notes able write security log seauditprivilege required default local system network service accounts privilege microsoft windows internals states processes call audit system services must seauditprivilege privilege successfully generate audit record winzapper faq notes possible add 'made event records log feature added considered nasty reference fact someone administrator access could use functionality shift blame unauthorized activity innocent party server 2003 added api calls applications could register security event logs write security audit entries specifically authzinstallsecurityeventsource function installs specified source security event source eventtracker newsletter states possibility tampering enough cause logs inadmissible must specific evidence tampering order logs considered inadmissible
|
Operating systems
|
circuit switching circuit switching method implementing telecommunications network two network nodes establish dedicated communications channel circuit network nodes may communicate circuit guarantees full bandwidth channel remains connected duration communication session circuit functions nodes physically connected electrical circuit defining example circuit-switched network early analog telephone network call made one telephone another switches within telephone exchanges create continuous wire circuit two telephones long call lasts circuit switching contrasts packet switching divides data transmitted packets transmitted network independently packet switching instead dedicated one communication session time network links shared packets multiple competing communication sessions resulting loss quality service guarantees provided circuit switching circuit switching bit delay constant connection opposed packet switching packet queues may cause varying potentially indefinitely long packet transfer delays circuit degraded competing users protected use callers circuit released new connection set even actual communication taking place channel remains reserved protected competing users virtual circuit switching packet switching technology emulates circuit switching sense connection established packets transferred packets delivered order circuit switching commonly used connecting voice circuits concept dedicated path persisting two communicating parties nodes extended signal content voice advantage using circuit switching provides continuous transfer without overhead associated packets making maximal use available bandwidth communication one disadvantage relatively inefficient unused capacity guaranteed connection used connections network call setup control administrative purposes possible use separate dedicated signalling channel end node network isdn one service uses separate signalling channel plain old telephone service pots method establishing connection monitoring progress termination network may also utilize separate control channel case links telephone exchanges use ccs7 packet-switched signalling protocol communicate call setup control information use tdm transport actual circuit data early telephone exchanges suitable example circuit switching subscriber would ask operator connect another subscriber whether exchange via inter-exchange link another operator case end result physical electrical connection two subscribers telephones duration call copper wire used connection could used carry calls time even subscribers fact talking line silent circuit switching contrasts packet switching divides data transmitted small units called packets transmitted network independently packet switching shares available network bandwidth multiple communication sessions multiplexing multiple telecommunications connections physical conductor possible long time nonetheless channel multiplexed link either dedicated one call time idle calls circuit switching route associated bandwidth reserved source destination making circuit switching relatively inefficient since capacity reserved whether connection continuous use contrast packet switching process segmenting data transmitted several smaller packets packet labeled destination sequence number ordering related packets precluding need dedicated path help packet find way destination packet dispatched independently may routed via different path destination original message reordered based packet number reproduce original message result datagram packet switching networks require circuit established allow many pairs nodes communicate concurrently channel
|
Internet protocols
|
lpx form factor lpx low profile extension originally developed western digital loosely defined motherboard format form factor widely used 1990s never official lpx specification design normally featured motherboard main i/o ports mounted back something later adopted atx form factor riser card center motherboard pci isa slots mounted due lack standardized specification riser cards seldom compatible one motherboard design another much less one manufacturer another internal psu connector type used form factor one successful features come lpx specification use compact power supplies later became widely used baby even full size cases lpx form factor power supplies became ubiquitous computer cases prior atx standard unusual manufacturers refer power supplies occasionally ps/2 power supplies due use ibm ps/2 even though actual baby power supply form factors larger size lpx form factor power supply eventually formed basis atx form factor power supply width height specification popular early-mid 90 briefly displaced form factor commonly used however release pentium ii 1997 highlighted flaws format good airflow important pentium ii systems owing relatively high heat dispersal requirements processor lpx systems suffered restricted airflow due centrally placed riser cards introduction agp format complicated matters design increased pin count riser cards limited cards one agp one pci one isa slot restrictive users lower-quality lpx boards n't even feature real agp slot simply used physical agp slot connected pci bus seldom noticed however many agp graphics cards time fact pci cards internally take advantage features offered agp lpx phased around 1998 nlx intended successor though many manufacturers chose microatx proprietary motherboard formats instead
|
Computer architecture
|
library computing computer science library collection non-volatile resources used computer programs often software development may include configuration data documentation help data message templates pre-written code subroutines classes values type specifications ibm os/360 successors referred partitioned data sets library also collection implementations behavior written terms language well-defined interface behavior invoked instance people want write higher level program use library make system calls instead implementing system calls addition behavior provided reuse multiple independent programs program invokes library-provided behavior via mechanism language example simple imperative language c behavior library invoked using c normal function-call distinguishes call library function versus another function program way code organized system library code organized way used multiple programs connection code part program organized used within one program distinction gain hierarchical notion program grows large multi-million-line program case may internal libraries reused independent sub-portions large program distinguishing feature library organized purposes reused independent programs sub-programs user needs know interface internal details library value library lies reuse behavior program invokes library gains behavior implemented inside library without implement behavior libraries encourage sharing code modular fashion ease distribution code behavior implemented library connected invoking program different program lifecycle phases code library accessed build invoking program library called static library alternative build executable invoking program distribute independently library implementation library behavior connected executable invoked executed either part process starting execution middle execution case library called dynamic library loaded run time dynamic library loaded linked preparing program execution linker alternatively middle execution application may explicitly request module loaded compiled languages standard library although programmers also create custom libraries modern software systems provide libraries implement majority system services libraries commoditized services modern application requires code used modern applications provided system libraries earliest programming concepts analogous libraries intended separate data definitions program implementation jovial brought compool communication pool concept popular attention 1959 although adopted idea large-system sage software following computer science principles separation concerns information hiding comm pool purpose permit sharing system data among many programs providing centralized data description cobol also included primitive capabilities library system 1959 jean sammet described inadequate library facilities retrospect another major contributor modern library concept came form subprogram innovation fortran fortran subprograms compiled independently compiler lacked linker prior introduction modules fortran-90 type checking fortran subprograms impossible finally historians concept remember influential simula 67 simula first object-oriented programming language classes nearly identical modern concept used java c++ c class concept simula also progenitor package ada module modula-2 even developed originally 1965 simula classes could included library files added compile time libraries important program linking binding process resolves references known links symbols library modules linking process usually automatically done linker binder program searches set libraries modules given order usually considered error link target found multiple times given set libraries linking may done executable file created whenever program used run time references resolved may addresses jumps routine calls may main program one module depending upon another resolved fixed relocatable addresses common base allocating runtime memory memory segments module referenced programming languages may use feature called smart linking whereby linker aware integrated compiler linker knows external references used code library never actually used even though internally referenced discarded compiled application example program uses integers arithmetic arithmetic operations exclude floating-point library routines smart-linking feature lead smaller application file sizes reduced memory usage references program library module stored relative symbolic form resolved code libraries assigned final static addresses relocation process adjusting references done either linker loader general relocation done individual libraries addresses memory may vary depending program using libraries combined position-independent code avoids references absolute addresses therefore require relocation linking performed creation executable another object file known static linking early binding case linking usually done linker may also done compiler static library also known archive one intended statically linked originally static libraries existed static linking must performed modules recompiled modules required program sometimes statically linked copied executable file process resulting stand-alone file known static build program static build may need relocation virtual memory used address space layout randomization desired shared library shared object file intended shared executable files shared object files modules used program loaded individual shared objects memory load time run time rather copied linker creates single monolithic executable file program shared libraries statically linked meaning references library modules resolved modules allocated memory executable file created often linking shared libraries postponed loaded modern operating systems shared library files format executable files offers two main advantages first requires making one loader rather two single loader considered well worth added complexity secondly allows executables also used shared libraries symbol table typical combined executable shared library formats elf mach-o unix pe windows older environments 16-bit windows mpe hp 3000 stack-based data local allowed shared-library code significant restrictions placed shared-library code library code may shared memory multiple processes well disk virtual memory used processes would execute physical page ram mapped different address spaces processes advantages instance openstep system applications often hundred kilobytes size loaded quickly majority code located libraries already loaded purposes operating system programs accomplish ram sharing using position-independent code unix leads complex flexible architecture using common virtual addresses windows os/2 systems make sure various tricks like pre-mapping address space reserving slots shared library code great probability shared third alternative single-level store used ibm system/38 successors allows position-dependent code places significant restrictions code placed shared cases different versions shared libraries cause problems especially libraries different versions file name different applications installed system require specific version scenario known dll hell named windows os/2 dll file modern operating systems 2001 clean-up methods eliminate situations use application-specific private libraries dynamic linking late binding linking performed program loaded load time executed run time rather executable file created dynamically linked library dynamic-link library dll windows os/2 dynamic shared object dso unix-like systems library intended dynamic linking minimal amount work done linker executable file created records library routines program needs index names numbers routines library majority work linking done time application loaded load time execution run time usually necessary linking program called dynamic linker linking loader actually part underlying operating system however possible exceedingly difficult write program uses dynamic linking includes dynamic linker even operating system provides support dynamic linking programmers originally developed dynamic linking multics operating system starting 1964 mts michigan terminal system built late 1960s since shared libraries systems change often systems compute likely load address shared library system needed store information libraries executables every shared library loaded undergone process load predetermined address speeds process dynamic linking optimization known prebinding macos prelinking linux disadvantages technique include time required precompute addresses every time shared libraries change inability use address space layout randomization requirement sufficient virtual address space use problem alleviated adoption 64-bit architectures least time loaders shared libraries vary widely functionality depend executable storing explicit paths libraries change library naming layout file system cause systems fail commonly name library path stored executable operating system supplying method find library disk based algorithm shared library executable depends deleted moved renamed incompatible version library copied place earlier search executable would fail load called dependency hell existing many platforms infamous windows variant commonly known dll hell problem occur version library uniquely identified program references libraries full unique identifiers dll hell problems earlier windows versions arose using names libraries guaranteed unique resolve dynamic links programs avoid dll hell later versions windows rely largely options programs install private dlls—essentially partial retreat use shared libraries—along mechanisms prevent replacement shared system dlls earlier versions microsoft windows checks registry determine proper place load dlls implement com objects dlls check directories defined order first windows checks directory loaded program private dll directories set calling codice_1 function system32 system windows directories current working directory finally directories specified path environment variable applications written .net framework framework since 2002 also check global assembly cache primary store shared dll files remove issue dll hell openstep used flexible system collecting list libraries number known locations similar path concept system first starts moving libraries around causes problems although users incur time cost first starting system unix-like systems search path specifying file-system directories look dynamic libraries systems specify default path configuration file others hard-code dynamic loader executable file formats specify additional directories search libraries particular program usually overridden environment variable although disabled setuid setgid programs user ca n't force program run arbitrary code root permissions developers libraries encouraged place dynamic libraries places default search path downside make installation new libraries problematic known locations quickly become home increasing number library files making management complex dynamic loading subset dynamic linking involves dynamically linked library loading unloading run time request request may made implicitly compile time explicitly run time implicit requests made compile time linker adds library references include file paths simply file names explicit requests made applications make direct calls operating system api run time operating systems support dynamically linked libraries also support dynamically loading libraries via run-time linker api instance microsoft windows uses api functions loadlibrary loadlibraryex freelibrary getprocaddress microsoft dynamic link libraries posix-based systems including unix unix-like systems use dlopen dlclose dlsym development systems automate process although originally pioneered 1960s dynamic linking reach operating systems used consumers late 1980s generally available form operating systems early 1990s period object-oriented programming oop becoming significant part programming landscape oop runtime binding requires additional information traditional libraries n't supply addition names entry points code located within also require list objects depend side-effect one oop main advantages inheritance means parts complete definition method may different places simply listing one library requires services another true oop system libraries may known compile time vary system system time many developers worked idea multi-tier programs display running desktop computer would use services mainframe minicomputer data storage processing instance program gui-based computer would send messages minicomputer return small samples huge dataset display remote procedure calls rpc already handled tasks standard rpc system soon majority minicomputer mainframe vendors instigated projects combine two producing oop library format could used anywhere systems known object libraries distributed objects supported remote access microsoft com example system local use dcom modified version supports remote access time object libraries held status next big thing programming world number efforts create systems would run across platforms companies competed try get developers locked system examples include ibm system object model som/dsom sun microsystems distributed objects everywhere doe next portable distributed objects pdo digital objectbroker microsoft component object model com/dcom number corba-based systems inevitable cooling marketing hype object libraries continue used object-oriented programming distributed information systems class libraries rough oop equivalent older types code libraries contain classes describe characteristics define actions methods involve objects class libraries used create instances objects characteristics set specific values oop languages like java distinction clear classes often contained library files like java jar file format instantiated objects residing memory although potentially able made persistent separate files others like smalltalk class libraries merely starting point system image includes entire state environment classes instantiated objects another solution library issue comes using completely separate executables often lightweight form calling using remote procedure call rpc network another computer approach maximizes operating system re-use code needed support library code used provide application support security every program additionally systems require library exist machine forward requests network however approach means every library call requires considerable amount overhead rpc calls much expensive calling shared library already loaded machine approach commonly used distributed architecture makes heavy use remote calls notably client-server systems application servers enterprise javabeans code generation libraries high-level apis generate transform byte code java used aspect-oriented programming data access frameworks testing generate dynamic proxy objects also used intercept field access system stores codice_2 codice_3 files directories codice_4 codice_5 codice_6 filenames always start codice_7 end suffix codice_8 archive static library codice_9 shared object dynamically linked library systems might multiple names dynamically linked library names names symbolic links remaining name names might include major version library full version number example systems codice_10 would filename second major interface revision dynamically linked library codice_11 codice_12 files sometimes found library directories libtool archives usable system system inherits static library conventions bsd library stored codice_8 file use codice_9-style dynamically linked libraries codice_15 suffix instead libraries macos however consist frameworks placed inside special directories called bundles wrap library required files metadata example framework called codice_16 would implemented bundle called codice_17 codice_18 either dynamically linked library file symlink dynamically linked library file codice_19 dynamic-link libraries usually suffix codice_20 although file name extensions may identify specific-purpose dynamically linked libraries e.g codice_21 ole libraries interface revisions either encoded file names abstracted away using com-object interfaces depending compiled codice_22 files either static libraries representations dynamically linkable libraries needed compilation known import libraries unlike unix world uses different file extensions linking codice_23 file windows one must first know regular static library import library latter case codice_24 file must present run time
|
Operating systems
|
datapath datapath collection functional units arithmetic logic units multipliers perform data processing operations registers buses along control unit composes central processing unit cpu larger datapath made joining one number datapaths using multiplexer late 1990s growing research area reconfigurable datapaths—datapaths may re-purposed run-time using programmable fabric—as designs may allow efficient processing well substantial power savings
|
Computer architecture
|
attitudinal analytics attitudinal analytics marketing technology application involves integration online surveys capture visitor intent critical demographic attributes tracking explicit behavior click stream monitoring websites quantitative user experience collects data thousands user sessions rather hundreds data typically compared key performance indicators performance customer satisfaction overall customer experience success failure reports finding recommendations used improve website customer experience program heavily dependent upon use online campaigns driving traffic website collection sites offline measurement also incorporated extend customer experience understanding illuminate elements online experience impacted offline behavior purchasing store visiting branch office several vendors provide attitudinal analytics solutions stand-alone offerings leading web analytics players also providing partner integration frameworks better integrate silos intent attitudinal behavioral data https //web.archive.org/web/20080311081258/http //www.usabilitysciences.com/category/case-studies/
|
Web technology
|
winzapper winzapper freeware utility hacking tool used delete events microsoft windows nt 4.0 windows 2000 security log developed arne vidstrom proof-of-concept tool demonstrating administrator account compromised event logs longer reliable according hacking exposed windows server 2003 winzapper works windows nt/2000/2003 prior winzapper creation administrators already ability clear security log either event viewer third-party tools clearlogs however windows lacked built-in method selectively deleting events security log unexpected clearing log would likely red flag system administrators intrusion occurred winzapper would allow hacker hide intrusion deleting log events relevant attack winzapper publicly released lacked ability run remotely without use tool terminal services however according arne vidstrom could easily modified remote operation also unrelated trojan horse name winzapper creates backup security log dummy.dat systemroot \system32\config file may undeleted attack recover original log conceivably however savvy user might copy sufficiently large file dummy.dat file thus irretrievably overwrite winzapper causes event viewer become unusable reboot unexpected reboot may clue winzapper recently used another potential clue winzapper-based attempt would corruption security log requiring cleared since always small risk winzapper according windowsnetworking.com one way prevent rogue admins using tool servers implement software restriction policy using group policy prevents winzapper executable running
|
Computer security
|
dynamic compilation dynamic compilation process used programming language implementations gain performance program execution although technique originated self best-known language uses technique java since machine code emitted dynamic compiler constructed optimized program runtime use dynamic compilation enables optimizations efficiency available compiled programs except code duplication metaprogramming runtime environments using dynamic compilation typically programs run slowly first minutes compilation recompilation done runs quickly due initial performance lag dynamic compilation undesirable certain cases implementations dynamic compilation optimizations could done initial compile time delayed compilation run-time causing unnecessary slowdowns just-in-time compilation form dynamic compilation closely related technique incremental compilation incremental compiler used pop-2 pop-11 forth versions lisp e.g maclisp least one version ml programming language poplog ml requires compiler programming language part runtime system consequence source code read time terminal file possibly data-structure constructed running program translated machine code block function may replace previous function name immediately available use program need speed compilation interactive development testing compiled code likely heavily optimised code produced standard 'batch compiler reads source code produces object files subsequently linked run however incrementally compiled program typically run much faster interpreted version program incremental compilation thus provides mixture benefits interpreted compiled languages aid portability generally desirable incremental compiler operate two stages namely first compiling intermediate platform-independent language compiling machine code host machine case porting requires changing 'back end compiler unlike dynamic compilation defined incremental compilation involve optimisations program first run
|
Programming language topics
|
menuconfig codice_1 one five similar tools configure linux source necessary early step needed compile source code codice_1 menu-driven user interface allows user choose features linux options compiled normally invoked using command codice_1 menuconfig target linux makefile codice_1 first version linux predecessor tool question-and-answer-based utility codice_5 codice_6 third tool linux configuration codice_7 requires qt also codice_8 uses gtk+ codice_9 similar codice_1 tools use kconfig language internally kconfig also used projects das u-boot bootloader embedded devices buildroot tool generating embedded linux systems busybox single-executable shell utility toolbox embedded systems despite simple design codice_1 offers considerable advantages question-and-answer-based configuration tool codice_6 notable basic search system ability load save files filenames different “ codice_13 ” codice_1 gives user ability navigate forwards backwards directly features rather using codice_5 pressing key many many times navigate linearly configuration specific feature user satisfied previous codice_13 file using codice_6 uses previous file answer questions interactively presenting new features intended version upgrade may appropriate times codice_1 light load system resources unlike codice_7 uses qt version 2.6.31.1 formerly tk codice_8 utilizes gtk+ possible ignore features codice_5 makes likely one configure incomplete oversized kernel recommended start codice_13 file included linux distribution makes easier configure custom kernel better editing codice_13 hand codice_1 shows descriptions feature adds primitive version 2.6.31.1 dependency checking make oldconfig dependency checking done one step requires user locate features changed hand sure needed ones still enabled practically using codice_1 codice_6 diff also cvs decent text editor provides flexibility dependability configuring linux significant labor users strongly advised make backups i.e codice_27 help information distributed throughout kernel source tree various files called kconfig use codice_1 linux source requirement make tool c compiler ncurses library left features setting empty enclosed two punctuation marks note supplied dependency information primitive tell names depentant features user encouraged read linux readme since also many make targets beyond modules_install install configure kernel different features activated using different interactive interface
|
Computer architecture
|
mysql workbench mysql workbench visual database design tool integrates sql development administration database design creation maintenance single integrated development environment mysql database system successor dbdesigner 4 fabforce.net replaces previous package software mysql gui tools bundle dbdesigner4 open source visual database design querying tool mysql database released gpl written 2002/2003 austrian programmer michael g. zinner fabforce.net platform using delphi 7 kylix 3 physical-modeling tool dbdesigner4 offers comprehensive feature set including reverse engineering mysql databases model-to-database synchronization model poster printing basic version control schema models sql query builder available ms windows mac os x linux late 2003 zinner approached representatives mysql ab joined company take development graphical user interface gui tools mysql led creation mysql gui tools bundle mysql gui tools bundle cross-platform open source suite desktop applications administration mysql database servers building manipulating data within mysql databases developed mysql ab later sun microsystems released gpl development gui tools bundle stopped preserved download archives mysql site gui tools bundle superseded mysql workbench reached end-of-life beta releases mysql workbench 5.2 however mysql support team continued provide assistance bundle june 30 2010 first preview version mysql workbench released september 2005 included mysql gui tools bundle development started 2007 mysql workbench set become mysql gui flagship product version numbering started 5.0 emphasise mysql workbench developed successor dbdesigner4 mysql workbench 5.0 5.1 specialized visual database design tools mysql database mysql workbench 5.0 ms windows-only product cross-platform support added mysql workbench 5.1 later starting mysql workbench 5.2 application evolved general database gui application apart physical database modeling features sql editor database migration tools database server administration interface replacing old mysql gui tools bundle may 22 2013 mysql workbench team announced working version 6.0 first public beta labeled version 6.0.2 released june 14 2013 first general-availability release made august 12 2013 january 23 2014 mysql workbench team announced first public beta release version 6.1 first general-availability release made march 31 2014 new features include improved visual explain output performance dashboard performance schema support additional query result views msaa support august 19 2014 mysql workbench team announced first public beta release version 6.2 first general-availability release made september 23 2014 new features shortcut buttons common operations pinning results tab microsoft access migration mysql fabric integration spatial view panel visualize spatial geometry data geometry data viewer result set width sql editor tabs properly saved shared snippets new run sql script dialog model script attachments client connections management new show details window information connections locks attributes displayed performance columns display sizes kb mb gb migration wizard resume operations data copying interrupted mysql connection password remembered across mysql workbench session march 5 2015 mysql workbench team announced first public beta release version 6.3 first general-availability release made april 23 2015 new features include fast migration option migrate data command-line instead gui ssl certificate generator improved sql auto-completion new table data import export wizard mysql enterprise firewall support version 6.3.8 mysql workbench macos incompatibilities macos sierra version 6.3.9 compatible macos sierra however n't work macos high sierra macos high sierra users need run version 6.3.10 april 5 2018 mysql workbench team announced first public release version 8.0.11 release candidate rc together mysql community server 8.0.11 first general availability ga release appeared july 27 2018 together server following new policy aligning version numbers across mysql products mysql workbench uses antlr4 backend parser new auto-completion engine works object editors triggers views stored procedures functions visual sql editor models new versions add support new language features mysql 8.0 common-table expressions roles also support invisible indexes persisting global system variables new default authentication plugin codice_1 mysql 8.0 supported workbench resetting user accounts authentication types longer necessary connecting latest servers administrative tabs updated latest configuration options user interface made consistent tabs prominent features mysql workbench mysql workbench first mysql family products offer two different editions open source proprietary edition community edition full featured product crippled way foundation editions benefit future development efforts proprietary standard edition extends community edition series modules plugins business decision announced soon takeover mysql sun microsystems caused speculation press future licensing mysql database since introduction mysql workbench become popular within mysql community second downloaded product mysql website 250,000 downloads month voted database tool year 2009 developer.com mysql workbench reviewed open source community print magazines
|
Databases
|
booting computing booting process starting computer initiated hardware button press software command switched computer central processing unit cpu software main memory process must load software memory executed may done hardware firmware cpu separate processor computer system restarting computer also called rebooting hard e.g electrical power cpu switched soft power cut systems soft boot may optionally clear ram zero hard soft booting initiated hardware button press software command booting complete operative runtime system typically operating system applications attained process returning computer state hibernation sleep involve booting minimally embedded systems require noticeable boot sequence begin functioning turned may simply run operational programs stored rom computing systems state machines reboot may method return designated zero-state unintended locked state addition loading operating system stand-alone utility boot process also load storage dump program diagnosing problems operating system boot short bootstrap bootstrap load derives phrase pull oneself one bootstraps usage calls attention requirement software loaded onto computer software already running computer mechanism must exist load initial software onto computer early computers used variety ad-hoc methods get small program memory solve problem invention read-only memory rom various types solved paradox allowing computers shipped start program could erased growth capacity rom allowed ever elaborate start procedures implemented many different methods available load short initial program computer methods reach simple physical input removable media hold complex programs early computers 1940s 1950s one-of-a-kind engineering efforts could take weeks program program loading one many problems solved early computer eniac program stored memory set problem configuration interconnecting cables bootstrapping apply eniac whose hardware configuration ready solving problems soon power applied edsac system second stored-program computer built used stepping switches transfer fixed program memory start button pressed program stored device david wheeler completed late 1948 loaded instructions punched tape executed first programmable computers commercial sale univac ibm 701 included features make operation simpler typically included instructions performed complete input output operation hardware logic could used load contents punch card typical ones input media magnetic drum magnetic tape contained bootstrap program pressing single button booting concept called variety names ibm computers 1950s early 1960s ibm used term initial program load ibm 7030 stretch later used mainframe lines starting system/360 1964 ibm 701 computer 1952–1956 load button initiated reading first 36-bit word main memory punched card card reader magnetic tape tape drive magnetic drum unit depending position load selector switch left 18-bit half-word executed instruction usually read additional words memory loaded boot program executed turn loaded larger program medium memory without help human operator term boot used sense since least 1958 ibm computers era similar features example ibm 1401 system c. 1958 used card reader load program punched card 80 characters stored punched card read memory locations 001 080 computer would branch memory location 001 read first stored instruction instruction always move information first 80 memory locations assembly area information punched cards 2 3 4 could combined form stored program information moved assembly area machine would branch instruction location 080 read card next card would read information processed another example ibm 650 1953 decimal machine group ten 10-position switches operator panel addressable memory word address 8000 could executed instruction thus setting switches 7004000400 pressing appropriate button would read first card card reader memory op code 70 starting address 400 jump 400 begin executing program card ibm competitors also offered single button program load noteworthy variation found burroughs b1700 neither bootstrap rom hardwired ipl operation instead system reset reads executes opcodes sequentially tape drive mounted front panel sets boot loader ram executed however since makes assumptions system equally well used load diagnostic maintenance test routine tapes display intelligible code front panel even cases gross cpu failure ibm system/360 successors including current z/architecture machines boot process known initial program load ipl ibm coined term 7030 stretch revived design system/360 continues use environments today system/360 processors ipl initiated computer operator selecting three hexadecimal digit device address cuu c=i/o channel address uu=control unit device address followed pressing load button high end system/360 models system/370 later systems functions switches load button simulated using selectable areas screen graphics console often ibm 2250-like device ibm 3270-like device example system/370 model 158 keyboard sequence 0-7-x zero seven x order results ipl device address keyed input area amdahl 470v/6 related cpus supported four hexadecimal digits cpus optional second channel unit installed total 32 channels later ibm would also support 16 channels ipl function system/360 successors compatibles amdahl reads 24 bytes operator-specified device main storage starting real address zero second third groups eight bytes treated channel command words ccws continue loading startup program first ccw always simulated cpu consists read ipl command command chaining suppress incorrect length indication enforced i/o channel commands complete first group eight bytes loaded processor program status word psw startup program begins execution location designated psw ipl device usually disk drive hence special significance read-type command exactly procedure also used ipl input-type devices tape drives even card readers device-independent manner allowing example installation operating system brand-new computer os initial distribution magnetic tape disk controllers command also causes selected device seek cylinder head simulating seek cylinder head command search record simulating search id equal command seeks searches simulated tape card controllers device classes command simply sequential read command read ipl command disk tape card deck must contain special program load actual operating system standalone utility main storage specific purpose ipl text placed disk stand-alone dasdi direct access storage device initialization program equivalent program running operating system e.g. ickdsf ipl-able tapes card decks usually distributed ipl text already present minicomputers starting digital equipment corporation dec pdp-5 pdp-8 1965 simplified design using cpu assist input output operations saved cost made booting complicated pressing single button minicomputers typically way toggle short programs manipulating array switches front panel since early minicomputers used magnetic core memory lose information power bootstrap loaders would remain place unless erased erasure sometimes happened accidentally program bug caused loop overwrote memory minicomputers simple form booting include hewlett-packard hp 2100 series mid-1960s original data general nova 1969 dec pdp-11 1970 dec later added optional diode matrix read-only memory pdp-11 stored bootstrap program 32 words 64 bytes consisted printed circuit card m792 plugged unibus held 32 16 array semiconductor diodes 512 diodes place memory contained one bits card programmed cutting diode whose bit zero dec also sold versions card bm792-yx series pre-programmed many standard input devices simply omitting unneeded diodes following older approach earlier pdp-1 hardware loader operator need push load switch instruct paper tape reader load program directly core memory data general supernova used front panel switches cause computer automatically load instructions memory device specified front panel data switches jump loaded code nova 800 1200 switch loaded program main memory special read-only memory jumped minicomputer paper tape reader first program run boot process boot loader would read core memory either second-stage boot loader often called binary loader could read paper tape checksum operating system outside storage medium pseudocode boot loader might simple following eight instructions related example based loader nicolet instrument corporation minicomputer 1970s using paper tape reader-punch unit teletype model 33 asr teleprinter bytes second-stage loader read paper tape reverse order length second stage loader final byte overwrites location 7 instruction location 6 executes location 7 starts second stage loader executing second stage loader waits much longer tape containing operating system placed tape reader difference boot loader second stage loader addition checking code trap paper tape read errors frequent occurrence relatively low-cost part-time-duty hardware teletype model 33 asr friden flexowriters far reliable also comparatively costly earliest microcomputers altair 8800 released first 1975 even earlier similar machine based intel 8008 cpu bootstrapping hardware started cpu would see memory would contain executable code containing binary zeros—memory cleared resetting powering front panels machines carried toggle switches entering addresses data one switch per bit computer memory word address bus simple additions hardware permitted one memory location time loaded switches store bootstrap code meanwhile cpu kept attempting execute memory content correctly loaded cpu enabled execute bootstrapping code process tedious error-free boot process minicomputers microcomputers revolutionized introduction integrated circuit read-only memory rom many variants including mask-programmed roms programmable roms prom erasable programmable roms eprom flash memory allowed firmware boot programs included part computer introduction external rom italian telephone switching elaborator called gruppi speciali patented 1975 alberto ciaramella researcher cselt gruppi speciali starting 1975 fully single-button machine booting operating system rom memory composed semiconductors ferrite cores although rom device natively embedded computer gruppi speciali due design machine also allowed single-button rom booting machines designed therefore bootstrap device architecture-independent e.g pdp-11 storing state machine switch-off also place another critical feature telephone switching contest typically every microprocessor reset power-on condition perform start-up process usually takes form begin execution code found starting specific address look multibyte code specific address jump indicated location begin execution system built using microprocessor permanent rom occupying special locations system always begins operating without operator assistance example intel x86 processors always start running instructions beginning f000 fff0 mos 6502 processor initialization begins reading two-byte vector address fffd ms byte fffc ls byte jumping location run bootstrap code apple inc. first computer apple 1 introduced 1976 featured prom chips eliminated need front panel boot process case altair 8800 commercial computer according apple ad announcing switches lights ... firmware proms enables enter display debug programs hex keyboard due expense read-only memory time apple ii series booted disk operating systems using series small incremental steps passing control onward next phase gradually complex boot process see apple dos boot loader little disk operating system relied rom hardware also extremely flexible supported wide range customized disk copy protection mechanisms see software cracking history operating systems notably pre-1995 macintosh systems apple closely interwoven hardware impossible natively boot operating system standard one opposite extreme scenario using switches mentioned highly inflexible relatively error-proof foolproof long hardware working normally common solution situations design boot loader works program belonging standard os hijacks system loads alternative os technique used apple a/ux unix implementation copied various freeware operating systems beos personal edition 5 machines like atari st microcomputer instant-on operating system executing rom retrieval os secondary tertiary store thus eliminated one characteristic operations bootstrapping allow system customizations accessories support software loaded automatically atari floppy drive read additional components boot process timeout delay provided time manually insert floppy system searched extra components could avoided inserting blank disk atari st hardware also designed cartridge slot could provide native program execution gaming purposes holdover atari legacy making electronic games inserting spectre gcr cartridge macintosh system rom game slot turning atari could natively boot macintosh operating system rather atari tos ibm personal computer included rom-based firmware called bios one functions firmware perform power-on self test machine powered read software boot device execute firmware compatible bios ibm personal computer used ibm pc compatible computers extensible firmware interface developed intel originally itanium-based machines later also used alternative bios x86-based machines including apple macs using intel processors unix workstations originally vendor-specific rom-based firmware sun microsystems later developed openboot later known open firmware incorporated forth interpreter much firmware written forth standardized ieee ieee standard 1275-1994 firmware implements standard used powerpc-based macs powerpc-based machines well sun sparc-based computers advanced risc computing specification defined another firmware standard implemented mips-based alpha-based machines sgi visual workstation x86-based workstations computer turned softwareincluding operating systems application code dataremains stored non-volatile memory computer powered typically operating system loader random-access memory ram computer first executes relatively small program stored read-only memory rom along small amount needed data access nonvolatile device devices operating system programs data loaded ram small program starts sequence known bootstrap loader bootstrap boot loader small program job load data programs executed ram often multiple-stage boot loaders used several programs increasing complexity load one process chain loading computer systems upon receiving boot signal human operator peripheral device may load small number fixed instructions memory specific location initialize least one cpu point cpu instructions start execution instructions typically start input operation peripheral device may switch-selectable operator systems may send hardware commands directly peripheral devices i/o controllers cause extremely simple input operation read sector zero system device memory starting location 1000 carried effectively loading small number boot loader instructions memory completion signal i/o device may used start execution instructions cpu smaller computers often use less flexible automatic boot loader mechanisms ensure computer starts quickly predetermined software configuration many desktop computers example bootstrapping process begins cpu executing software contained rom example bios ibm pc predefined address cpus including intel x86 series designed execute software reset without outside help software contains rudimentary functionality search devices eligible participate booting load small program special section commonly boot sector promising device typically starting fixed entry point start sector boot loaders may face peculiar constraints especially size instance ibm pc compatibles boot sector typically work 32 kb later relaxed 64 kb system memory use instructions supported original 8088/8086 processors first stage pc boot loaders fsbl first-stage boot loader located fixed disks removable drives must fit first 446 bytes master boot record order leave room default 64-byte partition table four partition entries two-byte boot signature bios requires proper boot loader — even less additional features like four partition entries 16 16 bytes disk signature 6 bytes disk timestamp 6 bytes advanced active partition 18 bytes special multi-boot loaders supported well environments floppy superfloppy volume boot records 59 bytes occupied extended bios parameter block fat12 fat16 volumes since dos 4.0 whereas fat32 ebpb introduced dos 7.1 requires even 87 bytes leaving 423 bytes boot loader assuming sector size 512 bytes microsoft boot sectors therefore traditionally imposed certain restrictions boot process example boot file located fixed position root directory file system stored consecutive sectors conditions taken care codice_1 command slightly relaxed later versions dos boot loader able load first three sectors file memory happened contain another embedded boot loader able load remainder file memory microsoft added lba fat32 support even switched boot loader reaching two physical sectors using 386 instructions size reasons time vendors managed squeeze much functionality single boot sector without relaxing original constraints minimal available memory 32 kb processor support 8088/8086 example dr-dos boot sectors able locate boot file fat12 fat16 fat32 file system load memory whole via chs lba even file stored fixed location consecutive sectors examples first-stage bootloaders include coreboot libreboot das u-boot second-stage boot loaders gnu grub bootmgr syslinux ntldr bootx operating systems able load operating system properly transfer execution operating system subsequently initializes may load extra device drivers second-stage boot loader need drivers operation may instead use generic storage access methods provided system firmware bios open firmware though typically restricted hardware functionality lower performance many boot loaders like gnu grub windows bootmgr windows nt/2000/xp ntldr configured give user multiple booting choices choices include different operating systems dual multi-booting different partitions drives different versions operating system case new version unexpected problems different operating system loading options e.g. booting rescue safe mode standalone programs function without operating system memory testers e.g. memtest86+ basic shell gnu grub even games see list pc booter games boot loaders also load boot loaders example grub loads bootmgr instead loading windows directly usually default choice preselected time delay user press key change choice delay default choice automatically run normal booting occur without interaction boot process considered complete computer ready interact user operating system capable running system programs application programs many embedded systems must boot immediately example waiting minute digital television gps navigation device start generally unacceptable therefore devices software systems rom flash memory device begin functioning immediately little loading necessary loading precomputed stored rom device made large complex systems may boot procedures proceed multiple phases finally operating system programs loaded ready execute operating systems designed never start stop boot loader might load operating system configure mere process within system irrevocably transfer control operating system boot loader terminates normally process would computers also capable booting computer network scenario operating system stored disk server certain parts transferred client using simple protocol trivial file transfer protocol tftp parts transferred operating system takes control booting process second-stage boot loader network booting begins using generic network access methods provided network interface boot rom typically contains preboot execution environment pxe image drivers required system functionality limited operating system kernel drivers transferred started result rom-based booting completed entirely possible network boot operating system ability use network interface boot device device operating system loaded modern pc uefi bios firmware supports booting various devices typically local solid state drive hard disk drive via gpt master boot record mbr drive disk optical disc drive using el torito usb mass storage device ftl-based flash drive sd card multi-media card slot hard disk drive optical disc drive etc network interface card using pxe older less common bios-bootable devices include floppy disk drives scsi devices zip drives ls-120 drives typically firmware uefi bios allow user configure boot order boot order set first dvd drive second hard disk drive firmware try boot dvd drive fails e.g dvd drive try boot local hard disk drive example pc windows xp installed hard drive user could set boot order one given insert linux live cd order try linux without install operating system onto hard drive example dual booting user chooses operating system start computer performed power-on self-test post example dual booting user chooses inserting removing cd computer common choose operating system boot selecting bios uefi boot menu using computer keyboard boot menu typically entered pressing keys post several devices available enable user quick-boot usually variant linux various simple tasks internet access examples splashtop latitude upon starting ibm-compatible personal computer x86 cpu executes real mode instruction located reset vector physical memory address 16-bit x86 processors 32-bit 64-bit x86 processors usually pointing firmware uefi bios entry point inside rom memory location typically contains jump instruction transfers execution location firmware uefi bios start-up program program runs power-on self-test post check initialize required devices dram pci bus including running embedded roms complicated step setting dram spi made difficult fact point memory limited initializing required hardware firmware uefi bios goes pre-configured list non-volatile storage devices boot device sequence finds one bootable bootable mbr device defined one read last two bytes first sector contain little-endian word found byte sequence disk also known mbr boot signature otherwise established code inside sector executable x86 pcs bios found bootable device loads boot sector linear address usually segment offset bioses erroneously use transfers execution boot code case hard disk referred master boot record mbr definition operating-system specific conventional mbr code checks mbr partition table partition set bootable one active flag set active partition found mbr code loads boot sector code partition known volume boot record vbr executes vbr often operating-system specific however operating systems main function load execute operating system kernel continues startup active partition active partition boot sector invalid mbr may load secondary boot loader select partition often via user input load boot sector usually loads corresponding operating system kernel cases mbr may also attempt load secondary boot loaders trying boot active partition else fails issue int 18h bios interrupt call followed int 19h case int 18h would return order give back control bios would attempt boot devices attempt remote boot via network invoke rom basic systems particularly newer macintoshes new editions microsoft windows use intel efi also coreboot allows computer boot without firmware/bios constantly running system management mode 16-bit bios interfaces required certain x86 operating systems dos windows 3.1/95/98 booted via uefi however boot loaders retain 16-bit bios call support modern cpus microcontrollers example ti omap sometimes even dsps may boot rom boot code integrated directly silicon processor could perform quite sophisticated boot sequence load boot programs various sources like nand flash sd mmc card difficult hardwire required logic handling devices integrated boot rom used instead scenarios boot rom usage enables flexible boot sequences hardwired logic could provide example boot rom could try perform boot multiple boot sources also boot rom often able load boot loader diagnostic program via serial interfaces like uart spi usb feature often used system recovery purposes reasons usual boot software non-volatile memory got erased could also used initial non-volatile memory programming clean non-volatile memory installed hence software available system yet embedded system designs may also include intermediary boot sequence step form additional code gets loaded system ram integrated boot rom additional code loaded way usually serves way overcoming platform limitations small amounts ram dedicated primary boot loader das u-boot loaded next step system boot sequence additional code boot sequence step usually referred secondary program loader spl also possible take control system using hardware debug interface jtag interface may used write boot loader program bootable non-volatile memory e.g flash instructing processor core perform necessary actions program non-volatile memory alternatively debug interface may used upload diagnostic boot code ram start processor core instruct execute uploaded code allows example recovery embedded systems software remains supported boot device processor integrated boot rom jtag standard popular interface many cpus microcontrollers devices manufactured jtag interfaces 2009 microcontrollers provide special hardware interfaces used take arbitrary control system directly run code instead allow insertion boot code bootable non-volatile memory like flash memory via simple protocols manufacturing phase interfaces used inject boot code possibly code non-volatile memory system reset microcontroller begins execute code programmed non-volatile memory like usual processors using roms booting notably technique used atmel avr microcontrollers others well many cases interfaces implemented hardwired logic cases interfaces could created software running integrated on-chip boot rom gpio pins digital signal processors serial mode boot parallel mode boot host port interface hpi boot case dsps often second microprocessor microcontroller present system design responsible overall system behavior interrupt handling dealing external events user interface etc dsp dedicated signal processing tasks systems dsp could booted another processor sometimes referred host processor giving name host port processor also sometimes referred master since usually boots first memories controls overall system behavior including booting dsp controlling dsp behavior dsp often lacks boot memories relies host processor supply required code instead notable systems design cell phones modems audio video players dsp cpu/microcontroller co-existing many fpga chips load configuration external serial eeprom configuration rom power-up
|
Operating systems
|
phoraging field computer security phoraging pronounced foraging defined process collecting data many different online sources build identity someone ultimate aim committing identity theft along phishing pharming third p cybercrime phoraging concept similar many ways phishing pharming information diving similar mosaic theory finance phoraging searching information usually aim identity theft whereby criminal collects data variety different online sources build identity consumer commit identity theft crooks phorage information variety different sources including social networking sites public records phishing attacks confidential information submitted unsecured way websites well computer viruses spyware put data together guess passwords answers security questions ultimate aim stealing money pc pro referred concept january 2009 issue security vendor verisign also use refer term uk office fair trading defines phoraging tactic used fraudsters aggregate personal information multiple sources intent misusing individual identity tactic known 'phoraging
|
Computer security
|
os/vs2 svs single virtual storage svs refers release 1 operating system/virtual storage 2 os/vs2 successor system mvt option operating system/360 os/vs2 svs stopgap measure pending availability mvs although ibm provided support enhancements svs long shipping mvs svs provides single 16mib address space shared tasks system regardless size physical memory os/360 used interval timer feature providing time day triggering time-dependent events support s/370 made limited use new timing facilities retained dependency interval timer svs uses tod clock clock comparator cpu timer exclusively wake applied data research lawsuit ibm decided although clear whether lawsuit actually deciding factor result svs include sort/merge program language processor new assembler xf replacing assembler f required system generation process authorized program facility apf new facility limited use certain dangerous services programs authorized link edited ac 1 loaded link list lpa sys1.svclib mvs ibm enhanced facility allow installation designate additional data sets authorized reader/interpreter svs runs pageable storage much less benefit automatic sysin batching asb reader svs include os/360 facility called direct sysout dso whereby specific output classes could diverted data sets tape instead normal spool datasets dasd prices dropped facility dropped use svs provide os/360 provided limited interactive facilities conversational remote job entry crje graphic job processing gjp interactive terminal facility itf satellite graphic job processing sgjp prior time sharing option tso ibm carry forward svs tso continues provide equivalent facilities except support use 2250 terminal use 2250 batch job using graphics access method gam graphics subroutine package gsp remains supported os/360 included batch debugging facility named testran clumsier equivalent facility ibsys/ibjob used much advent tso testran became even less relevant svs include dynamic support system dss new os/vs debugging facility system software remained available selectable unit 64 mvs/system extensions release 2 storage key facility system/360 system/370 keeps track page frame modified machine check handler mch svs correct parity ecc error unmodified page unassigning damaged page frame marking page table entry cause pagein operation newly assigned page table replaces special handling refreshable transient svc routines os/360 svs expands size error recovery procedure erp transient area none processors svs runs equivalent 2361 large core storage lcs thus need hierarchy support svs provide svs also dropped support obsolete i/o equipment os/360 load modules could permanently loaded initial program load ipl time area real storage known link pack area lpa svs lpa split three areas searched turn os/360 support multiprocessor version 360/65 svs provide equivalent support customers wanting run multiprocessor system/370 use mvs os/360 introduced telecommunications access method tcam successor queued telecommunications access method qtam svs include qtam svs include remote job entry rje however asp hasp provide comparable facilities larger 16 mib address space svs provides less external fragmentation mvt rollin/rollout would provide less benefit svs include os/360 transient svc routines loaded 1 kib areas known svc transient areas considerable amount code required manage svs svc routines preloaded virtual storage svc transient areas svs retains spool support os/360 shops used asp hasp precursors jes2 jes3 storage management svs similar mvt notable differences description somewhat simplified glosses special cases svs 16mib addressable storage single address space regardless size physical memory nucleus flpa virtual=real v=r meaning virtual address area mapped corresponding physical address job step svs request v=r storage assigned pages v=r region mapped corresponding real page frames program check occurs interrupt code 16 17 svs checks whether page assigned virtual address svs assign page frame read contents page page assigned svs causes abnormal end abend abend code 0c4 mvt would used protection violation svs provides services page fixing unfixing page fixed page frame subject page stealing primary purpose page fixing i/o i/o channels s/370 successors ability address translation however part support virtual storage operating systems ibm provided indirect data address ida feature channel control word ccw ida bit set points ida list idal rather directly i/o buffer svs provides ccw translation service part execute channel program excp svc excp necessary page fixing allocate storage ida lists translate virtual addresses real put translated addresses appropriate ida words put real addresses ida lists translated ccw i/o completes excp reverses process freeing storage translating status back virtual addition svs provides execute channel program real storage excvr svc privileged applications paged fixing build ida lists ibm provided several enhancements svs shipped part included
|
Operating systems
|
comparison arm cores comparison microarchitectures based arm family instruction sets designed arm holdings 3rd parties sorted version arm instruction set release name cores implement arm instruction set developed independently companies architectural license arm
|
Computer architecture
|
badlock badlock security bug disclosed april 12 2016 affecting security account manager sam local security authority domain policy lsad remote protocols supported windows samba servers sam lsad layered onto dce 1.1 remote procedure call dce/rpc protocol implemented samba windows rpc services allowed attacker become man middle although vulnerability discovered development samba namegiving smb protocol affected
|
Computer security
|
data exfiltration data exfiltration occurs malware and/or malicious actor carries unauthorized data transfer computer also commonly called data extrusion data exportation data exfiltration also considered form data theft past couple decades number data exfiltration efforts severely damaged consumer confidence corporate valuation intellectual property businesses national security governments across world data exfiltration scenarios large amount aggregated data may exfiltrated however scenarios likely certain types data may targeted types data targeted includes several techniques used malicious actors carry data exfiltration technique chosen depends number factors attacker easily gain physical privileged remote access server containing data wish exfiltrate chances success much better otherwise example would relatively easy system administrator plant turn execute malware transmits data external command control server without getting caught similarly one gain physical administrative access potentially steal server holding target data realistically transfer data server dvd usb flash drive many cases malicious actors gain physical access physical systems holding target data situations may compromise user accounts remote access applications using manufacturer default weak passwords 2009 analyzing 200 data exfiltration attacks took place 24 countries spiderlabs discovered ninety percent success rate compromising user accounts remote access applications without requiring brute-force attacks malicious actor gains level access may transfer target data elsewhere additionally sophisticated forms data exfiltration various techniques used conceal detection network defenses example cross site scripting xss used exploit vulnerabilities web applications provide malicious actor sensitive data timing channel also used send data packets time specified intervals way even difficult network defenses detect prevent number things done help defend network data exfiltration three main categories preventative measures may effective one example detective measures implement intrusion detection prevention systems regularly monitor network services ensure known acceptable services running given time suspicious network services running investigate take appropriate measures immediately preventative measures include implementation maintenance access controls deception techniques encryption data process transit rest investigative measures include various forensics actions counter intelligence operations
|
Computer security
|
non-local variable programming language theory non-local variable variable defined local scope term refer global variables primarily used context nested anonymous functions variables neither local global scope lua called upvalues function python 3 example follows nested function codice_1 defined scope another function codice_2 variable codice_3 local codice_2 non-local codice_1 global javascript locality variable determined closest codice_6 statement variable following example codice_3 local codice_2 contains codice_9 statement codice_1 n't therefore x non-local codice_1 haskell example follows variable codice_12 non-local anonymous function codice_13 non-local variables primary reason difficult support nested anonymous higher-order thereby first-class functions programming language nested function functions mutually recursive becomes hard compiler know exactly call stack non-local variable allocated frame pointer points local variable nested function arbitrary number activation records stack generally solved using access links display registers nested function passed argument higher-order function closure needs built order locate non-local variables nested function returned result outer function stored variable non-local variables longer available stack need heap allocated instead lifetime extend beyond lifetime outer function declared allocated generally requires garbage-collection
|
Programming language topics
|
information privacy information privacy relationship collection dissemination data technology public expectation privacy legal political issues surrounding also known data privacy data protection challenge data privacy use data protecting individual privacy preferences personally identifiable information fields computer security data security information security design use software hardware human resources address issue various types personal information often come privacy concerns describes ability control information one reveals oneself cable television access information example third parties track ip tv programs someone watched given time addition information broadcasting stream required audience rating survey additional devices requested installed houses viewers listeners without necessity cooperations audience ratings automatically performed real-time united kingdom 2012 education secretary michael gove described national pupil database rich dataset whose value could maximised making openly accessible including private companies kelly fiveash register said could mean child school life including exam results attendance teacher assessments even characteristics could available third-party organizations responsible anonymizing publications rather data anonymized government handed example data request gove indicated rejected past might possible improved version privacy regulations analysis sexual exploitation information person financial transactions including amount assets positions held stocks funds outstanding debts purchases sensitive criminals gain access information person accounts credit card numbers person could become victim fraud identity theft information person purchases reveal great deal person history places he/she visited he/she contacted products he/she used his/her activities habits medications he/she used cases corporations may use information target individuals marketing customized towards individual personal preferences person may may approve ability control information one reveals oneself internet access information become growing concern concerns include whether email stored read third parties without consent whether third parties continue track websites someone visited another concern websites visited collect store possibly share personally identifiable information users advent various search engines use data mining created capability data individuals collected combined wide variety sources easily ftc provided set guidelines represent widely accepted concepts concerning fair information practices electronic marketplace called fair information practice principles order give away much personal information emails encrypted browsing web pages well online activities done trace-less via anonymizers case trusted open-source distributed anonymizers called mix nets i2p tor – onion router vpns virtual private networks another anonymizer used give someone protection online includes obfuscating encrypting web traffic groups see mine email n't internet content privacy concerns age increasing amounts information going online social networking sites pose additional privacy challenges people may tagged photos valuable information exposed either choice unexpectedly others data location also accidentally published example someone posts picture store background caution exercised information posted social networks vary allow users make private remains publicly accessible without strong security settings place careful attention remains public person profiled searching collecting disparate pieces information worst case leading cases cyberstalking reputational damage location tracking capabilities mobile devices advancing location-based services problems related user privacy arise location data among sensitive data currently collected list potentially sensitive professional personal information could inferred individual knowing mobility trace published recently electronic frontier foundation include movements competitor sales force attendance particular church individual presence motel abortion clinic recent mit study de montjoye et al showed four spatio-temporal points approximate places times enough uniquely identify 95 1.5 million people mobility database study shows constraints hold even resolution dataset low therefore even coarse blurred datasets provide little anonymity people may wish medical records revealed others may concern might affect insurance coverages employment may would wish others know medical psychological conditions treatments would bring embarrassment upon revealing medical data could also reveal details one personal life three major categories medical privacy informational degree control personal information physical degree physical inaccessibility others psychological extent doctor respects patients ’ cultural beliefs inner thoughts values feelings religious practices allows make personal decisions physicians psychiatrists many cultures countries standards doctor–patient relationships include maintaining confidentiality cases physician–patient privilege legally protected practices place protect dignity patients ensure patients feel free reveal complete accurate information required receive correct treatment view united states laws governing privacy private health information see hipaa hitech act political privacy concern since voting systems emerged ancient times secret ballot simplest widespread measure ensure political views known anyone voters themselves—it nearly universal modern democracy considered basic right citizenship fact even rights privacy exist type privacy often unfortunately several forms voting fraud privacy violations possible use digital voting machines legal protection right privacy general – data privacy particular – varies greatly around world laws regulations related privacy data protection constantly changing seen important keep abreast changes law continually reassess compliance data privacy security regulations within academia institutional review boards function assure adequate measures taken ensure privacy confidentiality human subjects research privacy concerns exist wherever personally identifiable information sensitive information collected stored used finally destroyed deleted – digital form otherwise improper non-existent disclosure control root cause privacy issues data privacy issues may arise response information wide range sources heterogeneous information systems differing privacy rules interconnected information shared policy appliances required reconcile enforce monitor increasing amount privacy policy rules laws two categories technology address privacy protection commercial systems communication enforcement internet many users give away lot information unencrypted e-mails read administrators e-mail server connection encrypted https also internet service provider parties sniffing network traffic connection able know contents applies kind traffic generated internet including web browsing instant messaging others order give away much personal information e-mails encrypted browsing webpages well online activities done traceless via anonymizers open source distributed anonymizers so-called mix networks well known open-source mix nets include i2p – anonymous network tor computer privacy improved individualization currently security messages designed average user i.e message everyone researchers posited individualized messages security nudges crafted based users individual differences personality traits used improvements person compliance computer security privacy united states department commerce created international safe harbor privacy principles certification program response 1995 directive data protection directive 95/46/ec european commission directive 95/46/ec declares chapter iv article 25 personal data may transferred countries european economic area countries provide adequate privacy protection historically establishing adequacy required creation national laws broadly equivalent implemented directive 95/46/eu although exceptions blanket prohibition – example disclosure country outside eea made consent relevant individual article 26 1 – limited practical scope result article 25 created legal risk organisations transfer personal data europe united states program regulates exchange passenger name record information eu us according eu directive personal data may transferred third countries country provides adequate level protection exceptions rule provided instance controller guarantee recipient comply data protection rules european commission set working party protection individuals regard processing personal data commonly known article 29 working party working party gives advice level protection european union third countries working party negotiated u.s. representatives protection personal data safe harbor principles result notwithstanding approval self-assessment approach safe harbor remains controversial number european privacy regulators commentators safe harbor program addresses issue following way rather blanket law imposed organisations united states voluntary program enforced ftc u.s. organisations register program self-assessed compliance number standards deemed adequate purposes article 25 personal information sent organisations eea without sender breach article 25 eu national equivalents safe harbor approved providing adequate protection personal data purposes article 25 6 european commission 26 july 2000 safe harbor adoptee organisations need carefully consider compliance onward transfer obligations personal data originating eu transferred us safe harbor onward third country alternative compliance approach binding corporate rules recommended many eu privacy regulators resolves issue addition dispute arising relation transfer hr data us safe harbor must heard panel eu privacy regulators july 2007 new controversial passenger name record agreement us eu made short time afterwards bush administration gave exemption department homeland security arrival departure information system adis automated target system 1974 privacy act february 2008 jonathan faull head eu commission home affairs complained us bilateral policy concerning pnr us signed february 2008 memorandum understanding mou czech republic exchange visa waiver scheme without concerting brussels tensions washington brussels mainly caused lesser level data protection us especially since foreigners benefit us privacy act 1974 countries approached bilateral mou included united kingdom estonia germany greece
|
Computer security
|
core data core data object graph persistence framework provided apple macos ios operating systems introduced mac os x 10.4 tiger ios iphone sdk 3.0 allows data organized relational entity–attribute model serialized xml binary sqlite stores data manipulated using higher level objects representing entities relationships core data manages serialized version providing object lifecycle object graph management including persistence core data interfaces directly sqlite insulating developer underlying sql cocoa bindings handle many duties controller model–view–controller design core data handles many duties data model among tasks handles change management serializing disk memory footprint minimization queries data core data describes data high level data model expressed terms entities relationships plus fetch requests retrieve entities meeting specific criteria code retrieve manipulate data purely object level without worry details storage retrieval controller objects available interface builder retrieve manipulate entities directly combined cocoa bindings ui display many components data model without needing background code example developer might writing program handle vcards order manage author intends read vcards objects store single larger xml file using core data developer would drag schema data designer xcode interface builder window create gui schema could write standard objective-c swift code read vcard files put data core data managed entities point author code manipulates core data objects rather underlying vcards connecting codice_1 menu item appropriate method controller object direct controller examine object stack determine objects dirty re-write core data document file changes core data organized large hierarchy classes though interaction prevalent small set core data serialize objects xml binary sqlite storage release mac os x 10.5 leopard developers also create custom atomic store types method carries advantages disadvantages human readable xml memory efficient sqlite portion core data similar original enterprise objects framework eof system one write fairly sophisticated queries unlike eof possible write sql underlying store may sql-based recently core data store odbc made available odbc framework core data schemas standardized xcode data model file read write files format freely unlike eof though core data currently designed multiuser simultaneous access unless use odbc framework schema migration also non-trivial almost always requiring code developers access depend upon data model may need provide version translation code addition new data model schema changes core data owes much design earlier next product enterprise objects framework eof eof object-relational mapping high-end sql database engines microsoft sql server oracle eof purpose twofold first connect database engine hide implementation details second read data relational format translate set objects developers typically interacted objects simplified development complex programs cost setup map data objects eof object model deliberately designed make resulting programs work document-like fashion user could edit data locally memory write changes single save command throughout history eof contained number bits useful code otherwise available nextstep/openstep instance eof required ability track objects dirty system could later write presented developer document-like system also form unlimited undo command stack command applied data represented undoable action many developers complained state management code far useful isolated eof later moved cocoa api transition mac os x initially translated eof eof used primarily along another openstep-era product webobjects application server originally based objective-c. time apple process porting webobjects java programming language part conversion eof became much difficult use cocoa considerable complaining among 3rd party developers one critical realization object state management system eof really anything relational databases code could used developers manage graphs objects well role really useful parts eof automatically built object sets raw data tracked concept forms basis core data
|
Operating systems
|
james cordy james reginald cordy born january 2 1950 canadian computer scientist educator professor school computing queen university researcher currently active fields source code analysis manipulation software reverse re-engineering pattern analysis machine intelligence long record previous work programming languages compiler technology software architecture currently best known work txl source transformation language parser-based framework functional programming language designed support software analysis transformation tasks originally developed m.sc student charles halpern-hamu 1985 tool experimenting programming language design recent work nicad clone detector ph.d. student chanchal roy recognition strategy language ph.d. student richard zanibbi dorothea blostein cerno lightweight natural language understanding system john mylopoulos others university trento simone model clone detector manar alalfi thomas r. dean matthew stephan andrew stevenson based txl 1995 paper syntactic theory software architecture ph.d. student thomas r. dean widely cited seminal work area led work thomas r. dean kevin a. schneider andrew j. malton legacy systems analysis work programming languages included design concurrent euclid 1980 turing 1983 r.c holt implementation euclid 1978 sp/k 1974 languages r.c holt d.b wortman d.t barnard others part projects developed s/sl compiler technology r.c holt d.b wortman based m.sc thesis work orthogonal code generation method based ph.d. thesis work co-authored co-edited books turing programming language design definition 1988 introduction compiler construction using s/sl 1986 smart internet 2010 personal web 2013 2002 2007 director queen school computing 2008 elected distinguished scientist association computing machinery prolific academic supervisor 2008 recognized queen university award excellence graduate supervision 2016 queen university prize excellence research
|
Programming language topics
|
avx-512 avx-512 512-bit extensions 256-bit advanced vector extensions simd instructions x86 instruction set architecture isa proposed intel july 2013 supported intel xeon phi x200 knights landing skylake-x cpus includes core-x series excluding core i5-7640x core i7-7740x well new xeon scalable processor family xeon d-2100 embedded series avx-512 first 512-bit simd instruction set intel introduced processors earlier 512-bit simd instructions used xeon phi coprocessors derived intel larrabee project similar binary compatible partially source compatible avx-512 consists multiple extensions meant supported processors implementing policy departure historical requirement implementing entire instruction block core extension avx-512f avx-512 foundation required implementations avx-512 instruction set consists several separate sets unique cpuid feature bit however typically grouped supporting processor generation vex prefix used avx avx2 flexible leave enough room features intel wanted add avx-512 led define new prefix called evex compared vex evex adds following benefits extended registers simd width bit opmask registers avx-512 mandatory require support os avx-512 instructions designed mix 128/256-bit avx/avx2 instructions without performance penalty however avx-512vl extensions allows use avx-512 instructions 128/256-bit registers xmm/ymm sse avx/avx2 instructions new avx-512 versions encoded evex prefix allow access new features opmask additional registers unlike avx-256 new instructions new mnemonics share namespace avx making distinction vex evex encoded versions instruction ambiguous source code since avx-512f supports 32- 64-bit values sse avx/avx2 instructions operate bytes words supported avx-512bw extension byte word support width simd register file increased 256 bits 512 bits expanded 16 total 32 registers zmm0-zmm31 registers addressed 256 bit ymm registers avx extensions 128-bit xmm registers streaming simd extensions legacy avx sse instructions extended operate 16 additional registers xmm16-xmm31 ymm16-ymm31 using evex encoded form avx-512 instructions may indicate one 8 opmask registers k0–k7 first one k0 however hardcoded constant used indicate unmasked operations instructions opmask used control values written destination flag controls opmask behavior either zero zeros everything selected mask merge leaves everything selected untouched merge behavior identical blend instructions opmask registers normally 16 bits wide 64 bits avx-512bw extension many bits actually used though depends vector type instructions masked 32-bit single float double words 16 bits used mask 16 elements 512-bit register double float quad words 8 mask bits used opmask register reason several bitwise instructions naturally element widths added avx-512 instance bitwise 128-bit shuffle exist double-word quad-word variants difference final masking opmask registers new mini extension instructions operating directly unlike rest avx-512 instructions instructions vex encoded initial opmask instructions 16-bit word versions avx-512dq 8-bit byte versions added better match needs masking 8 64-bit values avx-512bw 32-bit double 64-bit quad versions added mask 64 8-bit values instructions kortest ktest used set x86 flags based mask registers may used together non-simd x86 branch conditional instructions many avx-512 instructions simply evex versions old sse avx instructions however several new instructions old instructions replaced new avx-512 versions new majorly reworked instructions listed foundation instructions also include extensions avx-512vl avx-512bw since extensions merely add new versions instructions instead new instructions evex-prefixed versions blend instructions sse4 instead avx-512 new set blending instructions using mask registers selectors together general compare mask instructions may used implement generic ternary operations cmov similar xop vpcmov since blending integral part evex encoding instruction may also considered basic move instructions using zeroing blend mode also used masking instructions avx-512f four new compare instructions like xop counterparts use immediate field select 8 different comparisons unlike xop inspiration however save result mask register initially support doubleword quadword comparisons avx-512bw extension provides byte word versions note two mask registers may specified instructions one write one declare regular masking final way set masks using logical set mask instructions perform either nand set destination opmask based result values zero non-zero note like comparison instructions take two opmask registers one destination one regular opmask compress expand instructions match apl operations name use opmask slightly different way avx-512 instructions compress saves values marked mask saves compacted skipping reserving space unmarked values expand operates opposite way loading many values indicated mask spreading selected positions new set permute instructions added full two input permutations take three arguments two source registers one index result output either overwriting first source register index register avx-512bw extends instructions also include 16-bit word versions avx-512_vbmi extension defines byte versions instructions two new instructions added logically implement possible bitwise operations three inputs take three registers input 8-bit immediate field bit output generated using lookup three corresponding bits inputs select one 8 positions 8-bit immediate since 8 combinations possible using three bits allow possible 3 input bitwise operations performed bitwise vector instructions avx-512f evex versions two source sse avx bitwise vector instructions andn xor added avx-512dq difference doubleword quadword versions application opmask truth table number conversion move instructions added complete set conversion instructions available sse2 among unique new features avx-512f instructions decompose floating-point values handle special floating-point values since methods completely new also exist scalar versions second set new floating-point methods includes new scaling approximate calculation reciprocal reciprocal square root approximate reciprocal instructions guarantee relative error 2 instructions avx-512 conflict detection avx-512cd designed help efficiently calculate conflict-free subsets elements loops normally could safely vectorized avx-512 exponential reciprocal instructions contain accurate approximate reciprocal instructions avx-512 foundation relative error 2 also contain two new exponential functions relative error 2 avx-512 prefetch instructions contain new prefetch operations new scatter gather functionality introduced avx2 avx-512 codice_1 prefetch means prefetching level 1 cache codice_2 means prefetching level 2 cache avx-512dq adds new doubleword quadword instructions avx-512bw adds byte words versions instructions adds byte word version doubleword/quadword instructions avx-512f instructions get word forms avx-512bw acquire byte forms avx-512_vbmi extension codice_3 codice_4 codice_5 codice_6 two new instructions added mask instructions set codice_7 codice_8 b w forms avx-512dq q avx-512bw rest mask instructions word forms got byte forms avx-512dq doubleword/quadword forms avx-512bw codice_9 extended codice_10 codice_11 avx-512bw among instructions added avx-512dq several sse avx instruction n't get avx-512 versions avx-512f among two input bitwise instructions extract/insert integer instructions instructions completely new covered three new floating point operations introduced since new avx-512 packed/simd scalar versions codice_12 instructions tests floating point value one eight special floating-point values eight values trigger bit output mask register controlled immediate field codice_13 instructions perform minimum maximum operations depending value immediate field also control operation done absolute separately sign handled codice_14 instructions operate single source subtract integer part source value plus number bits specified immediate field fraction extend vpcompress vpexpand byte word variants shift instructions new vector neural network instructions evex-encoded galois field new instructions vpclmulqdq avx-512f adds evex-encoded 512-bit version pclmulqdq instruction avx-512vl adds evex-encoded 256- 128-bit versions vpclmulqdq alone non-avx512 cpus adds vex-encoded 256-bit version availability vex-encoded 128-bit version indicated different cpuid bits pclmulqdq avx wider 128-bit variations instruction perform operation 128-bit portion input registers extend select quadwords different 128-bit fields meaning imm8 operand either low high quadword 128-bit field selected evex-encoded aes instructions wider 128-bit variations instruction perform operation 128-bit portion input registers intel vectorization advisor starting version 2016 update 3 supports native avx-512 performance vector code quality analysis 2nd generation intel xeon phi codenamed knights landing processor along traditional hotspots profile advisor recommendations seamless integration intel compiler vectorization diagnostics advisor survey analysis also provides avx-512 isa metrics new avx-512-specific traits e.g scatter compress/expand mask utilization
|
Computer architecture
|
highway encounter highway encounter computer game released sinclair zx spectrum 48k amstrad cpc msx commodore 64 tatung einstein vortex software 1985 written costa panayi also coded android two tll cyclone revolution highway encounter strategy/action game played 3d isometric perspective must successfully chaperone bomb along long straight stretch highway alien base end thirty screens pass filled hazards threaten block progress barrels destroy aliens explosive mines players control robotic vorton resembling dalek doctor one things provides highway encounter unique appeal bomb constantly pushed onwards extra lives four vortons accompany along highway key strategic element game player character travel several screens ahead bomb clear safe path normally would done temporarily blocking bomb forward motion however bomb left unsafe location possible extra lives lost without player character destroyed spare lives lost player character must manually push bomb spectrum version game voted number 40 sinclair official top 100 games time unfinished officially unreleased available download version atari st made mark haigh-hutchinson graphics costa panayi 1990 highway encounter followed sequel alien highway 1986
|
Computer architecture
|
dhs cyber security division cyber security division csd division science technology directorate united states department homeland security within homeland security advanced research projects agency csd develops technologies enhance security resilience united states critical information infrastructure acts terrorism
|
Computer security
|
evidence eliminator evidence eliminator computer software program ran microsoft windows operating system program deletes hidden information user hard drive normal procedures may fail delete cleaner eraser programs typically overwrite previously allocated disk space order make difficult salvage deleted information absence overwrite procedures information user thinks deleted may actually remain hard drive physical space claimed another use i.e. store another file offered sale program cost 149.99 evidence eliminator produced robin hood software based nottingham england version 6.04 controversy surrounding evidence eliminator marketing tactics company used popup ads market program including ads user system compromised response robin hood software produced dis-information page addressing concerns radsoft competitor robin hood criticised operation june 1 2005 peter beale one phoenix four used evidence eliminator remove trace certain files pc day appointment dti inspectors investigate collapse mg rover 2011 case mga v. mattel federal court found former employee used program delete information accused giving mga employed mattel howard marc watzman pedotrictian chicago financially connected belarus internet child trafficking ring used evidence eliminator attempt remove 200,000 images child pornography computer
|
Computer security
|
openbgpd openbgpd server software program allows general purpose computers used routers unix system daemon provides free open-source implementation border gateway protocol version 4 allows machine exchange routes systems speak bgp openbgpd developed henning brauer peter hessler claudio jeker part openbsd project openospfd developed esben nørby companion daemon openbgpd implements open shortest path first protocol suite developed alternative packages quagga linux-focused routing suite licensed gpl meet project requirements quality standards design goals openbgpd include secure non-exploitable reliable lean enough users size memory usage configuration language powerful easy use must also able quickly handle hundreds thousands table entries memory-efficient way openbgpd consists parent process two child processes route decision engine rde session engine se parent process part n't drop privileges others interest non-exploitability parent process drop privileges needs update routing table run root port
|
Operating systems
|
speedtree speedtree group vegetation programming modeling software products developed sold interactive data visualization inc. idv generates virtual foliage animations architecture real time video games demanding real time simulations speedtree licensed developers range video games microsoft windows xbox playstation console series since 2002 speedtree used 40 major films since release 2009 including iron man 3 star trek darkness life pi birdman used generate lush vegetation pandora avatar speedtree awarded scientific technical academy award 2015 presented idv founders michael sechrest chris king senior engineer greg croft speedtree conceptualized idv circa 2000 originated due firm lack satisfaction 3rd-party tree-generation software market initial version speedtreecad cad standing computer-aided design developed idv real-time golf simulation although backers pulled golf project idv refined cad software 3d studio max plug-in animated architectural rendering dubbing speedtreemax speedtreemax released february 2002 toward end 2002 idv released speedtreert real-time foliage/tree middleware sdk allowed automatic levels foliage detail real-time wind effects multiple lighting options idv eventually released plug-ins maya well appropriately named speedtreemaya early 2009 idv discontinued speedtreemax speedtreemaya plugins replacing speedtree modeler compiler products idv released speedtree 5 july 2009 version representing complete re-engineering software first versions speedtree enabling hand modeling editing vegetation models speedtree modeler replacing speedtreecad speedtreesdk replacing speedtreert speedtree compiler prepares speedtree files real-time rendering speedtree cinema first released idv 2009 based version 5 technology speedtree games version 6 released november 7 2011 essentially re-branded version speedtree 6 modeler compiler product identified speedtree games distinguish products meant gaming/real-time use speedtree architect released october 15 2012 designed architectural 3d cad use 3d fly-throughs idv released updated versions speedtree cinema speedtree studio speedtree architect november 2013 idv released speedtree v7 unreal engine 4 july 2014 idv released speedtree v7 unity 5 new engine version launch date march 2015 idv released speedtree games v7 april 16 2015 idv three engineers received scientific technical academy award 2015 speedtree cinema product suite speedtree cinema released idv 2009 saw first major use avatar james cameron speedtree cinema designed use film industry generates high-resolution meshes high-quality textures autodesk 3ds max autodesk maya cinema4d cinema edition includes speedtree modeler complete tree model library designed idv suites tree packs must purchased separately several members speedtree line simulate animated growth trees plants seasonal changes export data animated wind effects speedtree studio released idv 2009 less expensive companion speedtree cinema include cinema features complete tree model library speedtree architect released 2012 designed use 3d architectural cad generates meshes compatible typical architectural applications autodesk 3ds max autodesk maya rhino architect edition also exports normal maps uv maps physically-accurate rendering engines v-ray mental ray speedtree games edition speedtree video game development contrasting subscription edition offered users unity game development engine certain versions unreal engine 4 engine games edition includes modeler compiler sdk edition permits game developers integrate speedtree runtime technology game engine choice meshes generated system low poly multiple levels detail use texture atlases typically stored efficient binary format speedtree subscription edition low-cost edition speedtree modeler runtime targeted independent game studios licensing fee 19 usd monthly charge well additional charges tree packs subscribers get access speedtree editor ability generate 3d models trees plants plants exclusively usable either unreal engine 4 unity depending license subscribers download additional tree model packs model library pricing varies packs speedtree modeler windows-based specialized modeling tool designing foliage modeler features combination procedural tree generation hand-editing tools draw trees transform individual tree parts procedural tree generation uses configuration branch length branching angles bark texture generate tree variety formats newer versions support drag-and-drop interface automatically blends branch intersections handles branch collisions speedtree compiler software enables creation efficient tree models use real-time rendering video games generates texture atlases compiles optimizes tree models real-time use speedtree sdk multi-platform c++ sdk efficiently handles rendering speedtree-generated trees forests engine designed integrate operate within larger game engine ready-made support unreal engine unity ogre engine contains optimized systems cull off-screen trees determine level detail on-screen trees full source code available licensees use video games real-time applications modification engine supported engine built work microsoft windows mac os x xbox playstation playstation vita idv licensed middleware partner playstation 3 playstation 4 xbox 360 xbox one idv partnered epic games order integrate software epic unreal engine 4 unreal engine 3 free udk engine released november 2009 partnerships also formed idv bigworld tech vision engine havok multiverse network gamebryo engine emergent game technologies ogre open-source rendering engine torus knot speedtree games licensed first video games including december 2002 speedtree licensed pc next-generation console titles wide variety genres studios used speedtree published games featuring technology include selected recent upcoming and/or popular titles featuring speedtree games following release speedtree cinema 2009 speedtree saw first major cinematic use 2009 avatar technology provided vegetation flyover planet pandora first frames movie well scenes known movies television productions featuring speedtree include speedtree used following real-time projects offerings
|
Distributed computing architecture
|
connectionless communication connectionless communication often referred cl-mode communication data transmission method used packet switching networks data unit individually addressed routed based information carried unit rather setup information prearranged fixed data channel connection-oriented communication connectionless communication two network end points message sent one end point another without prior arrangement device one end communication transmits data addressed without first ensuring recipient available ready receive data protocols allow error correction requested retransmission internet protocol ip user datagram protocol udp connectionless protocols packet transmitted connectionless mode frequently called datagram connectionless protocols usually described stateless protocols end points protocol-defined way remember conversation message exchanges connection-oriented communication communicating peers must first establish logical physical data channel connection dialog preceding exchange user data connectionless communication advantage connection-oriented communication low overhead also allows multicast broadcast operations data transmitted several recipients single transmission connectionless transmissions service provider usually guarantee loss error insertion misdelivery duplication out-of-sequence delivery packet however effect errors may reduced implementing error correction within application protocol connectionless mode optimizations possible sending several data units two peers establishing connection beginning data exchange components routers bridges along network path would able pre-compute hence cache routing-related information avoiding re-computation every packet network components could also reserve capacity transfer subsequent data units video download example distinction connectionless connection-oriented transmission may take place several layers osi reference model
|
Internet protocols
|
h1droid h1droid project started vodafone sold samsung h1 mobile phones running limo operating system mobile phones running limo operating system applications also available limitation samsung h1 owners wanted run phone famous android operating system since phone good hardware attributes limo operating system also shared characteristics android could good platform operating system transformation idea group software enthusiast shared ideas blogsites world developed h1droid distributed internet software still development stage bugs ongoing h1droid android port samsung h1/gt-i8320/protector first steps porting android samsung h1 made ius netherlands k0059 china chinese programmer known mephisto continued k0059 work porting lot features like wifi improving power management mephisto faced many problems mainly related samsung libraries gave project people involved project recent updates made user called r3d4 https //github.com/r3d4/ ius currently working rewriting libsamsung-ipc support samsung h1 https //github.com/ius/ moment runs micro sd card means ca n't run samsung movinand however stills work fast microsd card currently using android 2.3.7 gingerbread working working bugs find games working working moment games tested samsung h1/gt-i8320/protector best install motorola droid 2 games/apps gpu samsung h1/gt-i8320/protector note moment bug 0.5.1 gameloft opening movies half sided n't worry wo n't affect gameplay n't want revert 0.5.0 find emulators working working moment games tested samsung h1/gt-i8320/protector
|
Operating systems
|
netsukuku netsukuku name experimental peer-to-peer routing system developed freaknet medialab 2005 created build distributed network anonymous censorship-free fully independent necessarily separated internet without support server isp central authority netsukuku designed handle 2 nodes without servers central systems minimal cpu memory resources mesh network built using existing network infrastructure components wi-fi project slow development since 2005 never abandoning beta state also never tested large scale december 2011 latest theoretical work netsukuku found author master thesis scalable mesh networks address space balancing problem following description takes account basic concepts theory netsukuku uses custom routing protocol called qspn quantum shortest path netsukuku strives efficient taxing computational capabilities node current version protocol qspnv2 adopts hierarchical structure 256 nodes grouped inside gnode group node 256 gnodes grouped single ggnode group group nodes 256 ggnodes grouped single gggnode offers set advantages main documentation protocol relies fact nodes mobile network structure change quickly several minutes may required change network propagated however node joins network immediately able communicate using routes neighbours node joins mesh network netsukuku automatically suits nodes come know fastest efficient routes communicate newcomer nodes privileges restrictions nodes domain name system dns replaced decentralised distributed system called andna netsukuku domain name architecture andna database included netsukuku system node includes database occupies 355 kilobytes memory simplifying andna works follows resolve symbolic name host applies function hash behalf hash function returns address host contacts asking resolution generated hash contacted node receives request searches andna database address associated name returns applicant host recording similar way example let suppose node x record address freaknet.andna x calculates hash name obtains address 11.22.33.44 associated node node x contacts requiring registration 11.22.33.44 hash stores request database request resolution 11.22.33.44 hash answer x address protocol obviously complex system provides public/private key authenticate hosts prevent unauthorized changes andna database furthermore protocol provides redundancy database make protocol resistant failures also provides migration database network topology changes protocol provide possibility revoking symbolic name certain period inactivity currently 3 days simply deleted database protocol also prevents single host record excessive number symbolic names present 256 names order prevent spammers store high number terms commonly used perform actions cybersquatting
|
Distributed computing architecture
|
euclid programming language euclid imperative programming language writing verifiable programs designed butler lampson associates xerox parc lab mid-1970s implementation led ric holt university toronto james cordy principal programmer first implementation compiler originally designed motorola 6809 microprocessor considered innovative time compiler development team 2 million budget 2 years commissioned defense advanced research projects agency u.s. department defense canadian department national defence used years i. p. sharp associates mitre corporation sri international various international institutes research systems programming secure software systems euclid descended pascal programming language functions euclid closed scopes may side effects must explicitly declare imports euclid also disallows gotos floating point numbers global assignments nested functions aliases none actual parameters function refer thing euclid implements modules types descendants euclid include mesa programming language concurrent euclid programming language turing programming language
|
Programming language topics
|
chart parser computer science chart parser type parser suitable ambiguous grammars including grammars natural languages uses dynamic programming approach—partial hypothesized results stored structure called chart re-used eliminates backtracking prevents combinatorial explosion chart parsing generally credited martin kay common approach use variant viterbi algorithm earley parser type chart parser mainly used parsing computational linguistics named inventor another chart parsing algorithm cocke-younger-kasami cyk algorithm chart parsers also used parsing computer languages earley parsers particular used compiler compilers ability parse using arbitrary context-free grammars eases task writing grammar particular language however lower efficiency led people avoiding compiler work bidirectional chart parsing edges chart marked direction either forwards backwards rules enforced direction edges must point order combined edges incremental chart parsing chart constructed incrementally text edited user change text resulting minimal possible corresponding change chart chart parsers distinguished top-down bottom-up well active passive
|
Computational linguistics
|
henry baker computer scientist henry givens baker jr. american computer scientist made contributions garbage collection functional programming languages linear logic also one founders symbolics company designed manufactured line lisp machines 2006 recognized distinguished scientist association computing machinery notable research garbage collection particularly baker real-time copying collector actor model baker received b.sc 1969 s.m 1973 e.e 1973 ph.d. 1978 degrees m.i.t
|
Programming language topics
|
open phone abstraction library field voip networking open phone abstraction library opal continues open-source openh323 project support wide range commonly used protocols used send voice video fax data ip networks rather tied h.323 protocol initially 2007 opal supported h.323 session initiation protocol sip protocols grown include asterisk iax2 opal implements wide range voice ip voip protocols voice video fax data ip networks written c++ released mozilla public licence opal utilises ptlib portable library allows opal run variety platforms including unix/linux/bsd macosx windows windows mobile embedded systems opal developed derivative openh323 library opal used open source video conferencing program ekiga formerly gnomemeeting
|
Internet protocols
|
cluster manager cluster manager usually backend graphical user interface gui command-line software runs one cluster nodes cases runs different server cluster management servers .the cluster manager works together cluster management agent agents run node cluster manage configure services set services manage configure complete cluster server see super computing cases cluster manager mostly used dispatch work cluster cloud perform last case subset cluster manager remote desktop application used configuration send work get back work results cluster cases cluster related availability load balancing computational specific service clusters
|
Distributed computing architecture
|
altergeo altergeo formerly known wi2geo russian company specializing development global hybrid positioning system combines wi-fi wimax gsm gps lte ip address network environment approaches also created cross-platform location-based services gvidi altergeo hyperlocal banner ad system local hero according financial times altergeo one four russia next tech titans company named winner finalist multiple domestic international awards field technology media currently skolkovo innovation center resident received funding several prominent investors including intel capital esther dyson altergeo established 2008 build wi-fi positioning technology basis phd thesis one founders long company goal develop universal solution could overcome limitations satellite systems gps a-gps glonass team expanded r activities developed global hybrid system positioning electronic devices wifi wimax gsm lte ip addresses network environment altergeo claim system significant coverage europe especially russia cis asia well north south america claim operate database 135 million wi-fi wimax gsm lte active access points processing 400 million location requests positioning 100 million devices world daily basis accuracy 20–30 metres hybrid system 500–1,000 metres ip-based positioning altergeo hybrid positioning system allows web mobile software developers well device manufacturers position users order provide location-aware features collect relevant location-based statistics marketing issues company also developed specific solutions precise location-based advertising targeting retargeting rtb etc indoor positioning altergeo system accessed api sdk deployed client side on-premises solution used badoo mail.ru 2gis livejournal prominent internet companies 2011 one russia largest advertising networks begun first russia launch location-based contextual advertising service thanks cooperation altergeo december 2014 altergeo released local hero self-service hyperlocal banner advertising system local businesses claims able publish customers banners throughout internet via several rtb ad exchanges display desktop mobile devices within small geographic areas minimum radius 500 meters demonstrate example alternative positioning system implemented field web mobile services wide audiences company started developing b2c location-based services launched 2008 location-based service altergeo began relatively simple friend-to-friend location-sharing service also allows people find places around give receive advice get various special offers e.g discount coupons restaurants shops places altergeo currently reported leading cross-platform location-based social network whole russian-speaking world 1.2 million people using website free mobile apps ios android windows phone additionally supplied augmented reality feature bada according techcrunch 2012 company realised sitting lot interesting data could applied restaurants released say 'intelligent restaurant guide gvidi free mobile app ios android based sophisticated recommendation system gvidi meaning guide head lead direct conduct combines directory restaurants cafes etc use social media try determine suitable user system monitors user social graphs facebook twitter altergeo vkontakte foursquare etc. well current location make recommendations restaurants cafes bars filtered across multiple criteria wi-fi 24/7 playground non-smoking table booking special offers also available altergeo winner techcrunch europas 2013 received best russian startup nomination company also bully awards 2012 named finalist red herring top 100 global red herring top 100 europe lists 2013 financial times listed altergeo among four russia next tech titans together yandex ozon ecwid whereas informilo included russia top 25 hottest tech companies list one year earlier altergeo recognized creation intelligent mobile restaurant search engine gvidi bully awards 2013 breakthrough technology-based product 2nd apps4all contest best app using google services named best idea project international tactrick android developer cup brands altergeo gvidi given highest possible index aaa russian startup rating top section
|
Web technology
|
mozilla skywriter mozilla skywriter formerly bespin mozilla labs project aiming create open extensible interoperable web-based framework code editing january 2011 merged ajax.org ace cloud9 ide projects original name reference bespin fictional gas giant star wars cloud city located relates cloud computing nature project time preceding 1.0 release name project changed skywriter due many compliments complaints previous one new name also holds reference coding cloud environment skywriter encourages shared environment data accessed machine allows developers collaborate projects unified interface accessed web browser matter physically located application available anyone free registration website skywriter currently supports syntax highlighting html css php python c c ruby javascript wiring used arduino platform
|
Distributed computing architecture
|
juice jacking juice jacking type cyber attack involving charging port doubles data connection typically usb often involves either installing malware surreptitiously copying sensitive data smart phone tablet computer device wall sheep event defcon set allowed public access informational juice jacking kiosk year defcon since 2011 intent bring awareness attack general public informational juice jacking kiosks set wall sheep village included hidden cpu used way notify user plug devices public charging kiosks first informational juice jacking kiosk included screen would change free charging station warning message user trust public charging stations devices one researchers designed charging station wall sheep given public presentations showcase malicious acts could taken via kiosk data theft device tracking information compromising existing charging kiosks security researcher kyle osborn released attack framework called p2p-adb 2012 utilized usb on-the-go connect attacker phone target victim device framework included examples proof concepts would allow attackers unlock locked phones steal data phone including authentication keys granting attacker access target device owner google account security researcher graduates students georgia institute technology georgia tech released proof concept malicious tool mactans utilized usb charging port apple mobile devices 2013 blackhat usa security briefings utilized inexpensive hardware components construct small sized malicious wall charger could infect iphone then-current version ios malicious software charged software could defeat security measures built ios mask way apple masks background processes ios security researchers karsten nohl jakob lell srlabs published research badusb 2014 blackhat usa security briefings presentation attack mentions cellphone tablet device charging infected computer would one simplest method propagating badusb vulnerability include example malicious firmware code would infect android devices badusb researchers aries security wall sheep later revisited juice jacking concept 2016 set video jacking charging station able record mirrored screen phones plugged malicious charging station affected devices time included android devices supporting slimport mhl protocols usb well recent iphone using lightning charge cable connector researchers symantec disclosed findings attack dubbed trustjacking 2018 rsa conference researchers identified user approves access computer ios device usb trusted access level also applied devices itunes api accessible wifi would allow attackers access ios device even user unplugged device malicious infected usb based charge source brian krebs first report attack coined term juice jacking seeing informational cell phone charging kiosk set wall sheep defcon 19 august 2011 wrote first article security journalism site krebs security wall sheep researchers—including brian markus joseph mlodzianowski robert rowley—designed kiosk information tool bring awareness potential attack vector discussed released tools publicly perform malicious actions charging devices episode hacking series hak5 released september 2012 showcased number attacks utilized using attack framework named p2p-adb released kyle osborn p2p-adb attack framework discussed utilized one phone attack another phone usb go connection late 2012 document released nsa warning government employees travel threat juice jacking reminding reader overseas travel use personal power charging cables charge public kiosks utilizing people computers android hackers handbook released march 2014 dedicated sections discussing juice jacking adb-p2p framework juice jacking central focus episode season 1 episode 9 l0m1s aired april 2015 apple ios taken multiple security measures reduce attack surface usb including longer allowing device automatically mount hard drive plugged usb well release security patches vulnerabilities exploited mactans android devices commonly prompt user allowing device mounted hard drive plugged usb since release 4.2.2 android implemented whitelist verification step prevent attackers accessing android debug bridge without authorization juice jacking possible device charged via ac adapter shipped device battery backup device utilizing usb cable data cables removed tool originally called usb condom renamed syncstop released sole purpose disallowing data connections passed usb cable
|
Computer security
|
mali gpu mali series graphics processing units gpus multimedia processors semiconductor intellectual property cores produced arm holdings licensing various asic designs arm partners mali gpus developed falanx microsystems a/s spun research project norwegian university science technology arm holdings acquired falanx microsystems a/s june 23 2006 renamed company arm norway like embedded ip cores 3d rendering acceleration mali gpu include display controllers driving monitors contrast common desktop video cards instead mali arm core pure 3d engine renders graphics memory passes rendered image another core handle display arm however license display controller sip cores independently mali 3d accelerator sip block e.g mali dp500 dp550 dp650 arm also supplies tools help authoring opengl es shaders named mali gpu shader development studio mali gpu user interface engine display controllers arm hdlcd display controller available separately mali core grew cores previously produced falanx currently constitute microarchitectures chips support cache coherency l2 cache cpu adaptive scalable texture compression astc supported mali-t620 t720/t760 t820/t830/t860/t880 mali-g series mali gpu variants found following systems chips socs mali video name given arm holdings dedicated video decoding video encoding asic multiple versions implementing number video codecs hevc vp9 h.264 vp8 arm products mali video processor semiconductor intellectual property core licensed third parties inclusion chips real time encode-decode capability central videotelephony interface arm trustzone technology also built-in enable digital rights management copyrighted material first version mali video processor v500 released 2013 mali-t622 gpu v500 multicore design sporting 1–8 cores support h.264 protected video path using arm trustzone 8 core version sufficient 4k video decode 120 frames per second fps v500 encode vp8 h.264 decode h.264 h.263 mpeg4 mpeg2 vc-1/wmv real vp8 released mali-t800 gpu arm v550 video processors added encode decode hevc support 10-bit color depth technologies reduced power consumption v550 also included technology improvements better handle latency save bandwidth built around idea scalable number cores 1–8 v550 could support 1080p60 1 core 4k120 8 cores v550 supported hevc main h.264 vp8 jpeg encode hevc main 10 hevc main h.264 h.263 mpeg4 mpeg2 vc-1/wmv real vp8 jpeg decode mali v61 video processor formerly named egil released mali bifrost gpu 2016 v61 designed improve video encoding particular hevc vp9 allow encoding either single multiple streams simultaneously design continues 1–8 variable core number design single core supporting 1080p60 8 cores drive 4kp120 decode encode vp9 10-bit vp9 8-bit hevc main 10 hevc main h.264 vp8 jpeg decode mpeg4 mpeg2 vc-1/wmv real h.263 mali v52 video processor released mali g52 g31 gpus march 2018 processor intended support 4k including hdr video mainstream devices mali v76 video processor released mali g76 gpu cortex-a76 cpu 2018 v76 designed improve video encoding decoding performance design continues 2–8 variable core number design 8 cores capable 8kp60 decoding 8kp30 encoding relative v61 support added 10-bit hdr h.264 encode decode however av1 codec supported mali-d71 added arm framebuffer compression afbc 1.2 encoder support arm corelink mmu-600 assertive display 5 assertive display 5 support hdr10 hybrid log-gamma hlg mali-d77 added features including asynchronous timewarp atw lens distortion correction ldc chromatic aberration correction cac mali-d77 also capable 3k 2880x1440 120hz 4k 90hz april 25th 2017 mali-c71 announced arm first image signal processor isp january 3th 2019 mali-c52 c32 announced aimed everyday devices including drones smart home assistants security internet protocol ip camera january 21 2012 phoronix reported luc verhaegen driving reverse-engineering attempt aimed mali series gpus specifically mali 200 mali 400 versions project known lima support opengl es 2.0 reverse-engineering project presented fosdem february 4 2012 followed opening website demonstrating renders february 2 2013 verhaegen demonstrated quake iii arena timedemo mode running top lima driver may 2018 lima developer posted driver inclusion linux kernel may 2019 lima driver part mainline linux kernel panfrost reverse-engineered driver effort mali txxx midgard gxx bifrost gpus introducing panfrost talk presented x.org developer conference 2018 may 2019 panfrost driver part mainline linux kernel
|
Computer architecture
|
vmac vmac open source emulator mac os windows dos os/2 nextstep linux-unix platforms although vmac abandoned mini vmac improved spinoff vmac currently developed vmac mini vmac emulate macintosh plus run apple macintosh system versions 1.1 7.5.5. vmac mini vmac support cpu emulation motorola 68000 68040 display output sound floppy disk insert hfv image files vmac ports include extra features cd-rom support basic serial port scc support gemulator rom board support various performance improvements although website still operation vmac development slowed halt 1999 official releases made since many developer e-mail addresses listed website currently working mini vmac vmac spinoff still maintained developed paul c. pratt currently mini vmac supports macintosh 128k 512k 512ke plus se classic active development macintosh ii macintosh portable powerbook 100 support due complaints rarity original ii also accepts macintosh iix macintosh se/30 rom files precompiled versions available download mini vmac sourceforge project emulates macintosh plus 4 mib ram vmac mini vmac require macintosh plus rom file macintosh system software work macintosh rom files owned apple legally distributed however windows unix ports vmac mini vmac support gemulator rom board emulators inc. allows users add genuine macplus rom chips x86 machine via isa expansion slot board also support rom chips early macintosh systems publicly released versions vmac supported macintosh plus macintosh system software available apple support downloads website see external links mentioned mini vmac also requires specific rom image computer emulation desired software application 68000 macs may downloaded mini vmac website retrieval system rom image along complete tutorial locating old mac retrieving rom working disk images
|
Computer architecture
|
cpmulator cpmulator program emulate cp/m operating system x86 dos program developed 1984 keystone software development company owned operated jay sprenkle nec v20 processor released year guaranteed hardware compatible intel 8088 reviewing instruction timing math operations instruction addressing hardware determined could slightly speed existing 8088 based ibm pc machines keystone software started advertising pc speedup kits pcweek magazine cpu socketed ibm pc could easily replaced practice programs received 5 speed increase math intensive much improved one customer reported monte carlo simulation nuclear reactor much faster double checked results could n't believe finished cpmulator developed release v20 processor also able emulate intel 8080 instruction set hardware opened possibility running older code new ibm machines cpmulator designed modify cp/m binaries make run native 8088 dos programs code put cpu emulation mode prefixed cp/m executable calls cp/m operating system intercepted translated dos operating system calls program would leave 8080 emulation mode make operating system call translate results cp/m standards returned emulation mode continue original program product went production class machines became prevalent nec produced v series pin pin compatible version 80286 processor
|
Operating systems
|
ourproject.org ourproject.org op web-based collaborative free content repository acts central location construction maintenance social/cultural/artistic projects providing web space tools focusing free knowledge claims extend ideas methodology free software social areas free culture general since september 2009 ourproject comunes association umbrella gave birth kune collaborative social network groups ourproject founded 2002 aims hosting boosting cooperative work done multiple domains cultural artistic educational one specific condition results projects remain freely accessible free license understood broad way available licenses cataloged free/libre several creative commons licenses non-profit perspective partially imposed online community projects advertising allowed hosted webpages thus ourproject projects mainly carried social movements university-supported groups free software related projects cooperatives artist collectives activist groups informal groups non-profits december 2016 ourproject.org hosting 1,733 projects 5,969 users constant linear growth rate pagerank 6 14th position public gforge sites first restricted free software projects fact gnu project highlights free knowledge free culture project claims successful wiki farm full free version without ads comparison presence especially spain latin america china relevant projects using ourproject infrastructure include 2011 attracted interest new wave protesting social movements several areas ourproject.org uses multi-language multiple-topic adapted version fusionforge aim widen spectrum free software ideals focusing free social cultural projects free software thus software originally kind social multiple-topic sourceforge following free culture movement nowadays ourproject community involved development collaborative environment kune eventually would cover current ourproject functionalities main condition hosting projects op content created project must released one licenses op provides several free internet services free/libre projects collaborators secondary services 9 years existence ourproject developed partnership several organizations
|
Web technology
|
new relic new relic american software analytics company based san francisco california lew cirne founded new relic 2008 company ceo name new relic anagram founder lew cirne name february 2013 new relic nr raised 80 million investors including insight venture partners t. rowe price benchmark capital allen company trinity ventures passport capital dragoneer tenaya capital valuation 750 million funding round helped new relic extend software analytics platform include android ios native mobile apps april 2014 new relic raised another 100 million funding led blackrock inc. passport capital participation t. rowe price associates inc. wellington management board members peter fenton benchmark dan scholnick trinity ventures peter currie currie capital adam messinger twitter sarah friar square lew cirne new relic went public december 12 2014 new relic technology delivered software service saas model announced 2013 monitors web mobile applications real-time support custom-built plugins collect arbitrary data partnerships include ibm bluemix amazon web services cloudbees engine yard heroku joyent rackspace hosting microsoft azure well mobile application backend service providers appcelerator parse stackmob marketing mentions november 5 2012 ca technologies formerly computer associates filed lawsuit us district court eastern district new york lawsuit claims new relic violated three patents came ca technologies possession acquisitions three patents question numbers b2 b1 b2 first two actions ca technologies filed connection alleged infringement patents obtained acquisition wily technology company also founded lew cirne april 2013 ca technologies filed lawsuit asserting patent infringement three apm patents software developer appdynamics however april 20 2015 appdynamics ca settled two-year-old patent dispute appdynamics said paid modest fixed payment
|
Distributed computing architecture
|
digic digital imaging integrated circuit often styled dig c canon inc. name family signal processing control units digital cameras camcorders digic units used image processors canon digital imaging products several generations digics exist distinguished version number suffix currently digic implemented application-specific integrated circuit asic designed perform high speed signal processing well control operations product incorporated numerous generations digic evolved system involving number discrete integrated circuits single chip system many based around arm instruction set custom firmware units developed add features cameras original digic used powershot g3 sep 2002 canon s1 mar 2004 a520 mar 2005 cameras consists three separate chips video processing ic image processing ic camera control ic digic ii single chip system introduced 2004 unlike first digic allowed compact designs digic ii also improved upon original adding larger buffer increasing processing speed used advanced consumer-level cameras many discontinued digital slrs canon eos 5d canon eos 30d digic ii uses high-speed ddr-sdram improves startup time af performance write memory card speeds 5.8 mb/sec additionally canon claims digic ii improves color sharpness automatic white balance cmos sensor digital slr camera line digic iii image processor introduced 2006 advertised deliver improved image quality faster operation extended battery life compared predecessor digic iii provides faster interface sd memory card canon powershot g7 g9 sd750 sd800 sd850 sd900 sd 1000 a560 a570 a590 a650 a720 a495 eos xs/1000d eos xsi/450d eos 40d eos 1d mark iii eos 1ds mark iii s5 also provides higher resolution lcd screens additionally 14-bit converter providing greater bit depth previous versions digic iii provides face detection af/ae finds tracks nine faces controls exposure flash ensure proper illumination faces well rest frame reducing detrimental effect overexposed darkened faces photo reverts aiaf system subject either detected deemed subject based isaps database latter useful tourist spots may many people around intended subject scene isaps scene-recognition technology developed canon digital cameras using internal database thousands different photos isaps also works digic iii image processor improve focus speed accuracy well exposure white balance canon eos-1d mark iii uses dual digic iii processors achieve capture rate 10 frames per second 10.1 mp maximum burst 110 jpeg images depending speed attached storage canon eos-1ds mark iii also uses dual digic iii processors achieve capture rate five frames per second 21.1 mp 2008 canon introduced digic 4 processor used eos 1100d/rebel t3 eos 500d/rebel t1i eos 550d/rebel t2i eos 600d/rebel t3i eos 50d eos 60d eos 1200d/rebel t5 eos 5d mark ii eos-1d x metering af also used newer cameras canon powershot lines g sd sx canon claims improvements dual digic 4 processors used eos 7d eos-1d mark iv cpu introduced 2014 replace digic 5 mid-range compact cameras particularly elph/ixus sx series full specifications made available introduction canon claims 60 speed bump original digic 4 2011 canon introduced digic 5 featured canon compact cameras like powershot sx40 hs achieve capture rate 10.3 frames per second full resolution high-speed burst hq full hd 1080p videos intelligent image stabilization canon claims new digic 5 processor six times faster digic 4 processor efficiently manages increase scene information simultaneously reduces appearance image noise 75 according canon digic 5 analyses four times image information create pixel recording detail colour scene ever digic 5 co-designed texas instruments ti manufactured ti foundry partnership asia using 45 nm node technology fanned ti digic 5 used eos 650d/rebel t4i/kiss x6i eos 700d/rebel t5i/kiss x7i canon eos eos 100d/rebel sl1/kiss x7 well powershot cameras canon powershot n s100 s110 g15 canon powershot sx50 hs digic 5+ enhancement digic 5 digic 4 performance said 17x performance digic 4 additional processing power allows higher frame rate continuous shooting burst modes greater noise correction use signal processing digic 5+ used eos-1d x eos 6d eos 5d mark iii eos 70d eos-1d x includes dual digic 5+ processors allowing capture rate 12 frames per second raw jpeg additional digic 4 processor specifically intelligent subject analysis system introduced 2013 digic 6 image processor enables improved low-light performance iso 6400 reduced noise addition enables improved af times reduced lag previous models improved performance allows shots 14 fps advancements attributed digic 6 experienced movie mode records mp4 format doubles frame-rate 60 fps 1080p also features reduced noise 30 fps improved image stabilization digic 6 used eos 750d/rebel t6i eos 760d/rebel t6s eos 80d powershot g16 powershot n100 powershot s120 powershot sx270 hs powershot sx280 hs powershot sx60 hs powershot sx700 hs powershot sx710 hs powershot sx720 hs february 2014 canon also released compact canon powershot g1 x mark ii released newest compact mirrorless canon eos m3 february 2015 canon eos m10 october 2015 also utilize internal wlan 802.11b/g/n canon eos 5d mark iv includes digic 6+ processor canon eos 7d mark ii includes dual digic 6 processors allowing capture rate 10 frames per second raw jpeg additional digic 6 processor specifically intelligent subject analysis system canon eos 5ds eos 5ds r also use dual digic 6 processors capability shoot five 50.6mp frames per second canon eos-1d x mark ii includes dual digic 6+ processors allowing capture rate 170 consecutive raw images 14 fps 4k video 60 fps introduced 2016 canon powershot g7 x mark ii first canon camera include digic 7 processor following cameras also using processor mirrorless interchangeable lens camera canon eos m5 introduced 2016 canon eos 77d canon eos 800d introduced february 2017 announced february 2017 canon eos m6 canon eos 6d mark ii released july 2017 canon eos 200d known eos rebel sl2 americas eos kiss x8 japan released july 2017 currently last series canon eos m100 released august 2017 digic 8 introduced together canon eos m50 february 2018 process 4k videos 30 fps using mpeg-4 avc/h.264 compression cameras using processor include digic dv used canon single-chip ccd digital camcorders well dc20 dc40 dvd camcorders digic dv ii utilizes hybrid noise reduction system new gamma system processor used canon high-definition camcorders exception dc20 dc40 dvd camcorders including new sd camcorders fs100 fs10 fs11 digic dv iii processor used legria pal /vixia ntsc high-definition hfs100 hfs10 hf200 hf20 digic dv iii also incorporated cinema eos line digital cinema camera commencing c300 late 2011 digic dv 4 processor introduced 2013 vixia/legria g r mini series camcorders well year xa-20 -25 professional camcorders canon claims capable recording simultaneous mp4 avchd video streams digic dv 5 first seen canon xc10 canon eos c300 mark ii announced 8 april 2015 right nab show xc10 uses single digic dv 5 c300 mark ii uses dual digic dv 5 implementation capable 4k 24 25 30fps 4:2:2 color sampling xf-avc h.264 codec digic dv 6 used canon eos c200 announced may 31 2017 c200 uses dual digic dv 6 implementation capable 4k 60fps digic board contains x86 compatible processor nec v30 emulation running datalight rom-dos s1is running vxworks two chips image processor motorola 68hc12 digic ii digic iii asics contain embedded 32-bit processors based arm instruction set around 2007 canon point-and-shoot cameras ran vxworks-based operating system recent cameras based dryos operating system developed in-house canon free software canon hack development kit chdk project started andrey gratchev successfully enhanced many canon powershot cameras without replacing stock firmware allows programmatic control many canon compact cameras enabling users add features including games scripts written ubasic lua features include shooting raw usb-cable remote shutter-release synchronized shooting multiple cameras motion-detection triggered photography customizable high-speed continuous burst tv av iso focus bracketing increasing depth field 1 gig video-size limit removed earlier cameras shutter aperture iso overrides shutter speeds 64 1/10,000 higher chdk project augment extend firmware necessary obtain copies cameras original firmware cases done via pure software method others rely method using blinking led camera optical serial port transmit firmware host computer however install precompiled firmware powershot camera necessary download correct binary copy sd memory card sd card set lock boot flag enabled camera turned camera autoboot binary file card chdk loaded camera ram card unlocked removed camera start original canon firmware chdk mask lock sd card camera still write however alternatively chdk loaded manually canon menu 400plus free firmware add-on offers additional functionality canon 400d non-destructive non-permanent way spy lantern surveillance camera commercial project based powershot chdk open script magic lantern firmware add-on written canon 5d mark ii trammell hudson 2009 ported 550d/t2i/kiss x4 1.0.8 july 2010 author starting september 2010 a1ex chdk forum people ported add-on 550d/t2i 1.0.9 60d 500d/t1i/kiss x3 600d/t3i/kiss x5 1.0.1 50d also runs 7d firmware released gnu general public license originally developed dslr filmmaking feature base expanded include tools useful still photography well current features include planned future features include clean hdmi output anamorphic preview custom curves installing magic lantern replace stock canon firmware modify rom rather runs alongside easy remove carries little risk canon made official statements regarding add-on firmware either subject warranty features
|
Computer architecture
|
dryos dryos real-time operating system made canon used latest digital cameras camcorders since late 2007 digic-based cameras shipped using dryos replaces vxworks wind river systems used digic2 digic ii digic3 digic iii cameras dryos existed use canon hardware digital video cameras high-end webcams dryos 16 kilobytes kernel module core currently compatible 10 cpu types provides simulation-based development environment debugging canon also developed usb- middleware-compatible device driver file systems network devices like video server dryos aims compatible µitron 4.0 posix following cameras known run dryos
|
Operating systems
|
bold delphi bold delphi advanced object relational mapper orm application framework written delphi designed significantly increase developer productivity providing following facilities application uses bold model created attributes links methods interface generated model application use application evolves model may need changed changes inteface generated well db-script sql code change database structure existing data database methods code preserved programmer make advanced use database without touching sql code good tutorial found bold founded boldsoft company stockholm framework sale borland bought boldsoft put hold discussions release code open source borland copyrights long time currently embarcadero legal rights framework bold still active developed attracs company eco follower bold delphi available .net framework bold delphi 2006
|
Databases
|
tulip system-1 tulip system 16-bit personal computer based intel 8086 made tulip computers formerly import company exidy sorcerer called compudata systems 6845-based video display controller could display 80×24 text 8 different fonts supporting different languages including videotex based font 2×3 pseudo graphic symbols displaying 160×72 pixel graphics text mode video display generator could also display graphics 384×288 768×288 color 768×576 monochrome pixel resolution using built-in nec 7220 video display coprocessor hardware supported drawing functions advanced set bit-block transfers could line generating arc circle ellipse ellipse arc filled arc filled circle filled ellipse filled elliptical arc many varied commands memory could upgraded units 128 kb 896 kb much 640 kb original pc included sasi hard disk interface predecessor scsi-standard optionally delivered 5 mb 10 mb hard disk floppy disk size 400 kb 10 sectors instead 8 9 ibm pc 800kb 80 tracks ran 8 mhz almost twice speed ibm pc xt launched months earlier july 1983 possibility use 8087 coprocessor math increased speed 200 kflops near mainframe data time initially using cp/m-86 quickly switched using generic ms-dos 2.00 rudimentary ibm-bios-emulator allowed user use wordstar ibm-pc software compudata b.v. shipped wordstar software adopted software computer programming support compudata b.v. ms-basic ms-pascal ms-fortran private base tex turbo pascal ported tulip system 1
|
Computer architecture
|
machine check architecture computing machine check architecture mca intel mechanism cpu reports hardware errors operating system intel pentium 4 intel xeon p6 family processors well itanium architecture implement machine check architecture provides mechanism detecting reporting hardware machine errors system bus errors ecc errors parity errors cache errors translation lookaside buffer errors consists set model-specific registers msrs used set machine checking additional banks msrs used recording errors detected
|
Computer architecture
|
sender id sender id anti-spoofing proposal former marid ietf working group tried join sender policy framework spf caller id sender id defined primarily experimental rfc 4406 additional parts rfc 4405 rfc 4407 rfc 4408 sender id heavily based spf additions differences discussed sender id tries improve spf spf verify header addresses one indicate claimed sending party one header addresses typically displayed user may used reply emails header addresses different address spf tries verify spf verifies mail address also called envelope sender however many similar email header fields contain sending party information therefore sender id defines rfc 4407 purported responsible address pra well set heuristic rules establish address many typical headers email syntactically sender id almost identical spf except codice_1 replaced one syntactical difference sender id offers feature positional modifiers supported spf practice far positional modifier specified sender id implementation practice pra scheme usually offers protection email legitimate offering real protection case spam phishing pra legitimate email either familiar header field case mailing lists sender header field case phishing spam however pra may based resent-* header fields often displayed user effective anti-phishing tool mua mail user agent mail client need modified display either pra sender id return-path header field spf pra tries counter problem phishing spf mfrom tries counter problem spam bounces auto-replies forged return-paths two different problems two different proposed solutions pra disadvantage forwarders mailing lists support modifying mail header e.g insert codice_6 codice_7 latter violates rfc 2822 incompatible rfc 822 spf mailing lists continue work forwarders wishing support spf need modify smtp mail rcpt mail new concept original rfc 821 smtp forwarders always added host name reverse path mail problematic point core sender id specification recommendation interpret codice_1 policies like codice_3 instead codice_2 never intended published spf drafts since 2003 unknown large number codice_1 policies evaluation pra could cause bogus results many cases pra mfrom different problem basis appeal internet architecture board iab response another prior appeal iesg already noted sender id advance ietf standards track without addressing incompatibility must rfc 2822 sender id proposal subject controversy regarding intellectual property licensing issues microsoft holds patents key parts sender id used license patents terms compatible gnu general public license considered problematic free software implementations general october 23 2006 microsoft placed patents open specification promise compatible free open source licenses recent version gpl license version 3.x
|
Computer security
|
larceny scheme implementation larceny implementation scheme programming language built around twobit optimizing compiler larceny offers several back-ends able target native x86 armv7 code petit larceny also available emits c source code compiled native code ordinary c compiler older versions 0.98 included support sparc architecture larceny microsoft common language runtime via common larceny larceny supports major scheme standards rrs ieee/ansi rrs rrs larceny software open source available online
|
Programming language topics
|
terascale microarchitecture terascale codename family graphics processing unit microarchitectures developed ati technologies/amd second microarchitecture implementing unified shader model following xenos terascale replaced old fixed-pipeline microarchitectures competed directly nvidia first unified shader microarchitecture named tesla terascale used hd 2000 manufactured 80 nm 65 nm hd 3000 manufactured 65 nm 55 nm hd 4000 manufactured 55 nm 40 nm hd 5000 hd 6000 manufactured 40 nm terascale also used amd accelerated processing units code-named brazos llano trinity richland terascale even found succeeding graphics cards brands terascale vliw simd architecture tesla risc simd architecture similar terascale successor graphics core next terascale implements hyperz llvm code generator i.e compiler back-end available terascale seems missing llvm matrix e.g mesa 3d makes use siggraph 08 december 2008 amd employee mike houston described terascale microarchitecture fosdem09 matthias hopf amds technology partner suse linux presented slide regarding programming open-source driver r600 previous gpu architectures implemented fixed-pipelines i.e distinct shader processors type shader terascale leverages many flexible shader processors scheduled process variety shader types thereby significantly increasing gpu throughput dependent application instruction mix noted r600 core processes vertex geometry pixel shaders outlined direct3d 10.0 specification shader model 4.0 addition full opengl 3.0 support new unified shader functionality based upon long instruction word vliw architecture core executes operations parallel shader cluster organized 5 stream processing units stream processing unit retire finished single precision floating point mad add mul instruction per clock dot product dp special cased combining alus integer add 5th unit complex additionally handle special transcendental functions sine cosine shader cluster execute 6 instructions per clock cycle peak consisting 5 shading instructions plus 1 branch notably vliw architecture brings classic challenges inherent vliw designs namely maintaining optimal instruction flow additionally chip co-issue instructions one dependent results performance gpu highly dependent mixture instructions used application well real-time compiler driver organize said instructions r600 core includes 64 shader clusters rv610 rv630 cores 8 24 shader clusters respectively terascale includes multiple units capable carrying tessellation similar programmable units xenos gpu used xbox 360 tessellation officially specified major api starting directx 11 opengl 4 terascale 1 2 based gpu hd 2000 3000 4000 series conformant direct3d 10 opengl 3.3 terascale 3 based gpu starting radeon hd 5000 series first conform direct3d 11 opengl 4.0 supporting tesselation feature de facto terascale tessellator units allow developers take simple polygon mesh subdivide using curved surface evaluation function different tessellation forms bézier surfaces n-patches b-splines nurbs also subdivision techniques surface usually includes displacement map kind texture essentially allows simple low-polygon model increased dramatically polygon density real-time small impact performance scott wasson tech report noted amd demo resulting model dense millions polygons appeared solid terascale tessellator reminiscent ati truform brand name early hardware tessellation unit used initially radeon 8500 tessellation hardware part opengl 3.3 direct3d 10.0 requirements competitors geforce 8 series lacked similar hardware microsoft added tessellation feature part directx 10.1 future plans ati truform received little attention software developers games madden nfl 2004 serious sam unreal tournament 2003 2004 unofficially morrowind support ati tesselation technology included slow adaptation fact feature shared nvidia gpus since implemented competing tessellation solution using quintic-rt patches achieved even less support major game developers since xbox 360 gpu based ati architecture microsoft saw hardware-accelerated surface tessellation major gpu feature couple years later tesselation feature became mandatory release directx 11 2009 gcn geometric processor amd acquired ati gpu business current solution carrying tessellation using gpu although r600 significant departure previous designs still shares many features predecessor radeon r520 ultra-threaded dispatch processor major architectural component r600 core radeon x1000 gpus processor manages large number in-flight threads three distinct types vertex geometry pixel shaders switches amongst needed large number threads managed simultaneously possible reorganize thread order optimally utilize shaders words dispatch processor evaluates goes parts r600 attempts keep processing efficiency high possible lower levels management well simd array 80 stream processors sequencer arbiter arbiter decides thread process next sequencer attempts reorder instructions best possible performance within thread texturing final output aboard r600 core similar also distinct r580 r600 equipped 4 texture units decoupled independent shader core like r520 r580 gpus render output units rops radeon hd 2000 series performs task multisample anti-aliasing msaa programmable sample grids maximum 8 sample points instead using pixel shaders radeon x1000 series also new capability filter fp16 textures popular hdr lighting full-speed rop also perform trilinear anisotropic filtering texture formats r600 totals 16 pixels per clock fp16 textures higher precision fp32 textures filter half-speed 8 pixels per clock anti-aliasing capabilities robust r600 r520 series addition ability perform 8× msaa 6× msaa r300 r580 r600 new custom filter anti-aliasing cfaa mode cfaa refers implementation non-box filters look pixels around particular pixel processed order calculate final color anti-alias image cfaa performed shader instead rops brings greatly enhanced programmability filters customized may also bring potential performance issues use shader resources launch r600 cfaa utilizes wide narrow tent filters samples outside pixel processed weighted linearly based upon distance centroid pixel linear function adjusted based wide narrow filter chosen memory controllers connected via internal bi-directional ring bus wrapped around processor radeon hd 2900 1,024-bit bi-directional ring bus 512-bit read 512-bit write 8 64-bit memory channels total bus width 512-bits 2900 xt radeon hd 3800 512-bit ring bus radeon hd 2600 hd 3600 256-bit ring bus radeon hd 2400 hd 3400 ring bus series saw half-generation update die shrink 55 nm variants rv670 rv635 rv620 variants support pci express 2.0 directx 10.1 shader model 4.1 features dedicated ati unified video decoder uvd models powerplay technology desktop video cards except radeon hd 3800 series variants supported 2 integrated displayport outputs supporting 24- 30-bit displays resolutions 2,560×1,600 output included 1 2 4 lanes per output data rate 2.7 gbit/s per lane ati claimed support directx 10.1 bring improved performance processing efficiency reduced rounding error 0.5 ulp compared average error 1.0 ulp tolerable error better image details quality global illumination technique used animated films improvements consumer gaming systems therefore giving realistic gaming experience see list chips pages terascale 2 vliw5 introduced radeon hd 5000 series gpus baptized evergreen hpg10 mark fowler presented evergreen stated e.g 5870 cypress 5770 juniper 5670 redwood support max resolution 6 times 2560×1600 pixels 5470 cedar supports 4 times 2560×1600 pixels important amd eyefinity multi-monitor support release cypress terascale graphics engine architecture upgraded twice number stream cores texture units rop units compared rv770 architecture stream cores largely unchanged adds support directx 11/directcompute 11 capabilities new instructions also similar rv770 four texture units tied 16 stream cores five processing elements making total 80 processing elements combination referred simd core unlike predecessor radeon r700 directx 11 mandates full developer control interpolation dedicated interpolators removed relying instead simd cores stream cores handle higher rounding precision fused multiply–add fma instruction single double precision increases precision multiply–add mad compliant ieee 754-2008 standard instruction sum absolute differences sad natively added processors instruction used greatly improve performance processes video encoding transcoding 3d engine simd core equipped 32 kib local data share 8 kib l1 cache simd cores share 64 kib global data share memory controller ties two quad rops one per 64-bit channel dedicated 512 kib l2 cache redwood one quad rop per 256-bit channel amd powerplay supported see terascale 3 vliw4 replaces previous 5-way vliw designs 4-way vliw design new design also incorporates additional tessellation unit improve direct3d 11 performance terascale 3 implemented radeon hd 6900-branded graphics cards also trinity richland apus chips baptized northern islands family amd powertune dynamic frequency scaling gpus introduced radeon hd 6900 december 15 2010 prone development ever since like couple reviews anandtech document hpg11 august 2011 amd employees michael mantor senior fellow architect mike houston fellow architect presented graphics core next microarchitecture succeeding terascale
|
Computer architecture
|
single version truth computerized business management single version truth svot technical concept describing data warehousing ideal either single centralised database least distributed synchronised database stores organisation data consistent non-redundant form contrasts related concept single source truth ssot refers data storage principle always source particular piece information one place systems context message processing systems often realtime systems term also refers goal establishing single agreed sequence messages within database formed particular arbitrary sequencing records key concept data combined certain sequence truth may analyzed processed giving particular results although sequence arbitrary thus another correct equally arbitrary sequencing would ultimately provide different results analysis desirable agree sequence enshrined single version truth version considered truth conclusions drawn analysis database valid unarguable technical context database may duplicated backup environment ensure persistent record kept single version truth key point database created using external data source sequence trading messages stock exchange arbitrary selection made one possibility two equally valid representations input data henceforth decision sets stone one one version truth critics svot applied message sequencing argue concept scalable world moves towards systems spread many processing nodes effort involved negotiating single agreed-upon sequence becomes prohibitive pointed owen rubel api world talk 'the new api pattern svot always going service layer distributed architecture input/output meet also endpoint binding belongs allow modularization better abstraction i/o data across architecture avoid architectural cross cutting concern
|
Databases
|
touchwiz touchwiz samsung touchwiz user interface created designed developed samsung electronics partners featuring full touch user interface touchwiz available samsung devices sometimes incorrectly identified operating system touchwiz used internally samsung smartphones feature phones tablet computers available licensing external parties android version touchwiz also comes samsung-made app store galaxy apps first original edition touchwiz released 2008 1.0 version officially launched original samsung solstice 2009 latest version touchwiz touchwiz 6.0 samsung galaxy j1 mini prime touchwiz nature ux 5.0 samsung galaxy j3 2016 feature refined user interface compared previous versions found samsung older phones released prior galaxy s5 release status bar transparent home screen mode touchwiz nature ux 2.0 touchwiz nature ux 2.5 touchwiz 4.0 galaxy ii galaxy note later updated nature ux features added include panning tilt makes use accelerometer gyroscope phone detect motion touchwiz abandoned samsung late 2016 favor samsung experience touchwiz used samsung proprietary operating systems bada rex well phones based android operating system also present phones running tizen operating system touchwiz central issue apple v. samsung released 2010 support android froyo 2.1 – 2.2 version premiered samsung galaxy s. lite version touchwiz 3.0 reduced features used samsung galaxy proclaim second version touchwiz released 2011 support android gingerbread android honeycomb 2.3 3.2.6 galaxy ii first device preloaded touchwiz 4.0 version includes better hardware acceleration 3.0 well multiple touchscreen options involving multi-touch gestures using phone accelerometer one feature allows users place two fingers screen tilt device towards away zoom respectively panning touchwiz 4.0 allows users scroll home screens moving device side side third version touchwiz renamed touchwiz nature ux released 2012 supported android ice cream sandwich 4.0 galaxy iii galaxy star galaxy note 10.1 first devices preloaded version although lite version used beforehand samsung galaxy tab 2 7.0 touchwiz nature ux contains interactive elements previous version water ripple effect lock screen smart stay feature uses eye tracking technology determine user still watching screen complement touchwiz interface response apple siri version introduces voice samsung intelligent personal assistant version supports android jellybean 4.2.2 released 2013 samsung galaxy s4 first device use touchwiz nature ux 2.0 even eye tracking abilities introduced version smart scroll allows users scroll webpages tilting head downwards upwards respectively touchwiz nature ux 2.5 released 2013 support last updates android jellybean 4.3 4.4 first used galaxy note 3 galaxy note 10.1 2014 edition version completely supports samsung knox security solution well multi-user capabilities camera also improved update shutter lag reduced features like 360° panorama mode added update released 2014 support android kitkat first seen galaxy s5 galaxy note pro 12.2 home screen settings menu made user-friendly larger icons less clutter also icons context menus removed disabled options previously would visible unusable show budget devices samsung galaxy trend 2 lite galaxy j1 ace galaxy v plus feature reduced version touchwiz nature ux 3.0 called touchwiz essence ux adapted devices less 1 gb ram version ultra-power-saving mode drastically extends battery duration making screen grayscale restricting apps used turning features like wi-fi bluetooth slightly modified version touchwiz nature ux 3.0 released 2014 galaxy note 4 galaxy note edge galaxy a-series 2015 changes made minor aesthetic ones including overhaul cluttered settings menu inclusion quick setting shortcuts centralization lock screen clock however camera application stripped basic features nonetheless gaining af/ae lock version comes galaxy s5 supports android lollipop released 2015 update 4.0 eventually became available galaxy s5 note 3 note 4 lollipop-compatible devices less features version touchwiz continued design initially seen galaxy s5 slightly rounded icons also incorporated lollipop additions changes making notification drop-down menu merely overlay instead full-screen drawer touchwiz nature ux 4.0 also included visual overhaul whole system changing black background system apps white theme similar touchwiz ux 3.5 seen note 4 series black theme place since original galaxy reduced battery consumption samsung mainly uses amoled display technology changed patent licensing deal google required touchwiz interface follow design stock android closely touchwiz 5.0 samsung reverted earlier simpler naming system without nature ux infix perhaps reflect aesthetic changes version released 2015 primarily samsung galaxy s6 supports later updates android lollipop 5.0.2 5.1.1 update cleaned user interface reduced number duplicate functions used brighter simpler colours new version touchwiz 5.0 released september 2015 galaxy note 5 s6 edge+ new version features updated iconography stock apps featuring squircle icons instead freeform version touchwiz began initial beta testing android marshmallow galaxy s6 december 2015 users signed beta program became formally available february 2016 features redesigned notification drop-down colour overhaul replacing original blue green hue white version also removed weather centring enlarging clock lock screen well bringing back ability customize shortcuts lock screen icons slightly modified flatter look removing shadows featured previously smart manager removed app moved settings option instead version samsung also added ability change display density setting although initially accessible third-party app setting hidden system update galaxy s7 s7 edge made official allowing users change display settings touchwiz 6.0 also includes google additions android doze app standby improve battery performance although samsung app optimization feature remains available thus meaning two separate app optimization settings one within smart manager app within battery usage screen tap quickly access intelligent personal assistant google permission control limit permissions granted particular application first released samsung galaxy note 7 android marshmallow grace ux named device codename eventually made way older devices including galaxy note 5 update galaxy s7 s7 edge official android nougat update grace ux features cleaner flatter look iconography extensive use white space touchwiz grace ux devices also benefit secure folder functionality enables users keep certain data even apps behind secure password addition countries languages absent previous versions android marshmallow earlier available release starting galaxy tab s3
|
Operating systems
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.