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instantgo instantgo formerly connected standby microsoft specification windows 8 hardware software aims bring smartphone-type power management capabilities pc platform well increasing physical security specification describes microsoft proprietary standard windows 8 software hardware developers hardware vendors optionally comply meet user requirements devices able turned instantly mode also allows operating system continue performing background tasks updating content apps devices must able turn less 500 milliseconds hardware requirements extend battery life systems must drain 5 battery capacity idle 16-hour period requires following additional security-specific requirements example memory soldered motherboard prevent cold boot attack vectors involve removing memory machine well support secure boot windows 8.1 supporting instantgo trusted platform module tpm 2.0 chip allow device use passive device encryption system systems support specification incapable booting legacy bios operating systems pcs connected standby also manually enter sleep hibernate power states
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Operating systems
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programming domain programming domain defines specific kind use programming language examples programming domains
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Programming language topics
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nitix nitix properly pronounced /nitiks/ retail linux distribution produced canada software developed net integration technologies inc. acquired ibm january 2008 currently operates ibm lotus foundations nitix originally named weaver first created september 1997 linux-based server required little configuration primarily built pre-configured hardware platforms named net integrators nitix first became standalone operating system capable deployment third-party hardware january 2004 programming earliest versions weaver done primarily avery pennarun dave coombs students university waterloo nitix claimed linux-based os autonomic features june 2004 ibm press released new book autonomic computing mentions nitix nitix one first companies deliver promise autonomic technology complete set intelligent networking solutions smb market june 2005 nitix virtual server released allowed hosting applications system architecture application services nitix allowed applications run virtual server environment completely separated controlled os environment virtual server rpm based filesystem incorporates yellow dog updater modified application retrieval tool simultaneously net integration technologies began sponsoring ready nitix program encouraged independent software vendors certify applications nitix also june 2005 nitix began support ns3 scalable services structure allows centralized user management across multiple servers well dns propagation march 2007 nitixblue released new flavor nitix nitixblue supports nearly hands-free installation ibm lotus domino touting administrative headaches complete automation maintenance tasks considered large step small medium businesses previously realistic stepping stone towards enterprise-level functionality provided ibm lotus domino january 2008 ibm announced acquire net integration technologies functions separate entity lotus software group nitix includes automated installation process installs onto hard disks performs proper partitioning system setup process also performs network scan determines whether enable dhcp server finds gateway internet access automatically configures firewall modifications installation process keyboard monitor attached server changes made console modifications made web interface web interface designed access needed configuration modifications cases interface set users teams file access email collaboration exchangeit antivirus antispam web sites ftp rsync services nfs samba appletalk nitix offers multi-layer security protection based anti-virus technology kaspersky anti-spam technology vircom engate nitix claim fame proprietary intelligent disk backup idb automatically backs files emails databases incrementally often every 15 minutes backups made hard drive located system rotated provide off-site redundancy restoring files done individually user entire system web-based interface u.s. patent 7,165,154 nitix includes many open source applications provide lot functionality january 18 2008 ibm announced intention purchase net integrations technologies ibm merged products offering known ibm lotus foundations lotus foundations offered software-only application server platform well hardware appliance known net integrator july 2 2008 ibm officially started offering lotus foundations opposed nitix blue ibm lotus foundations products withdrawn marketing march 14 2013 longer available purchase support ibm lotus foundations products withdrawn september 30 2014 nitix discontinued favour ibm lotus foundations start nitix currently sold distribution channel either software-only net integrator software-only versions nitix sb nitix se nitix pe come 1 cd geared towards partners complement third party hardware systems nitix differences number client access licenses included software assurance prices nitix also pre-configured hardware systems named micro micro 2 mark mark ii hardware selection depends number hard drives form factor nitix discontinued sale distribution channels favor latest lotus foundations start support active value added resellers purchase lotus foundations resell end users part complete solution usually involving services custom made applications
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Operating systems
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microsoft digital crimes unit microsoft digital crimes unit dcu microsoft sponsored team international legal internet security experts employing latest tools technologies stop interfere cyber crime cyber threats microsoft digital crimes unit assembled 2008 shortly 2013 cybercrime center dcu opened redmond washington 100 members dcu stationed redmond washington original cybercrime center members dcu include lawyers data scientists investigators forensic analysts engineers dcu international offices located major cities beijing berlin bogota delhi dublin hong kong sydney washington d.c dcu main focuses child protection copyright infringement malware crimes dcu must work closely law enforcement ensure perpetrators punished full extent law dcu taken many major botnets citadel rustock zeus around world malware cost users 113 billion dcu jobs shut accordance law three areas dcu concentrates trespass chattel legal term microsoft digital crimes unit takes cyber criminals chattel old english cattle considered valuable property owner essentially meaning property land referred chattel cattle spam malware infects user computer network considered trespass chattel trespassing user property cybercrime criminal trespassed user computer network responsible spam malware intended harm user dcu legal team pursue cyber criminal court using old legal doctrines laws charge crime trespassing botnet network compromised computer zombies controlled without user knowledge usually used repetitive tasks spam also used distributing malware distributed denial service ddos attacks botnets controlled single criminal network criminals microsoft digital crimes unit constantly hunting botnet networks used tasks dcu dealt botnets spamming key-logging data ransom dcu also taken botnets citadel rustock zeus everyday fight dcu continue locate new threats botnets take march 18th 2011 microsoft digital crimes unit took rustock botnet rustock botnet responsible half spam worldwide sent users controlled 1 million computers spam viruses attached emails phishing emails microsoft help u.s marshals got warrants seize identified local command-and-control servers analysis dcu u.s. marshals raided servers located chicago columbus dallas denver kansas city scranton seattle dcu seized servers terminated entire world large decrease spam since spam rustock botnet march 25th 2012 microsoft digital crimes unit took zeus botnet investigation also known operation b71 zeus botnet responsible stealing 100 million 13 million infected computers botnet installed user computer pirated versions windows hidden download online zeus botnet works waiting user computer open web browser attempt banking online shopping show similar looking webpage field enter login information login information sent zeus server criminal access user accounts dcu accompanied u.s marshals shut botnet raiding two command-and-control server facilities located scranton pennsylvania lombard illinois dcu made case prosecute 39 unnamed cyber criminals responsible botnet accessing servers retrieving stolen data botnet shut starter code since sold black market make variations botnet citadel many therefore zeus botnet code still active evolved june 6th 2013 microsoft digital crimes unit took citadel botnet 1000 servers citadel botnet infected estimated 5 million computers using key-logging program steal information citadel responsible stealing least 500 million online personal bank accounts 80 countries stole banks american express bank america paypal hsbc royal bank canada wells fargo citadel code emerged cybercrime kit known zeus sold starter code black market thousands creators citadel unknown dcu prepared large amount charges prosecute dcu since helped users update systems get rid malware may still computers inactive december 5 2013 microsoft digital crimes unit fbi europol industry partners attempted disrupt zeroaccess botnet although efforts took 18 hosts part zeroaccess command control network peer-to-peer nature botnet zeroaccess remains active
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Computer security
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knightmare 1986 video game knightmare short 1986 msx vertical scrolling shooter computer game player knight popolon fight way several levels defeat hudnos rescue aphrodite knightmare innovative upward-scrolling shoot 'em game msx system released game cartridge top-view graphics considered sophisticated time similar msx games nemesis penguin adventure konami also released slightly altered version could bought links network japanese internet replacement 80 version could submit high scores online server
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Computer architecture
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patrick naughton patrick naughton american software developer one creators java programming language 1983 naughton co-wrote macpaint clone painter apprentice russ nelson sun microsystems engineer patrick naughton become frustrated state sun c++ c apis application programming interfaces tools considering moving next naughton offered chance work new technology thus stealth project started stealth project soon renamed green project james gosling mike sheridan joining naughton together engineers began work small office sand hill road menlo park california attempting develop new technology programming next generation smart appliances sun expected major new opportunity june july 1994 three days brainstorming john gage director science sun james gosling bill joy naughton wayne rosing eric schmidt team re-targeted platform world wide web felt advent first graphical web browser mosaic internet way evolving highly interactive medium envisioned cable tv prototype naughton wrote small browser webrunner later renamed hotjava 1994 naughton quit sun starwave property paul allen develop server java applications web sites author java handbook osborne 1995 co-author java complete reference herbert schildt osborne 1996 1998 walt disney internet group acquired starwave amalgamated infoseek go network company result naughton became executive vice president infoseek arrest 1999 naughton fired infoseek sept. 14 1999 naughton flew seattle los angeles private disney jet expecting five-foot blonde haired 13-year-old girl wait pier near roller coaster carrying green backpack instructed naughton naughton written love sex wanted get alone hotel room nowiki /nowiki nowiki /nowiki strip naked naughton arranged meeting posing hot seattle online predator handle online chat room called dad daughtersex girl actually fbi agent two days later arrested fbi charged traveling interstate commerce intent sex minor violation 18 u.s.c §2423 b trial ended hung jury naughton struck plea agreement took reduced sentence admitted traveled seattle los angeles last september dominant purpose engage sexual acts krisla online chat buddy believed 13-year-old girl ended serving prison time exchange working fbi free year line defense claimed persuaded participate online ritualized sexual role-playing exercise dealing mature woman acting girl then-novel defense became known fantasy defense pedophiles
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Programming language topics
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sinec h1 sinec h1 industrial ethernet communications protocol provides transport layer function widely used automation process control applications protocol developed siemens used mainly control applications large bandwidth well suited transmission large volumes data used part control infrastructure cern lhc
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Internet protocols
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criticism linux criticism linux focuses issues concerning use operating systems use linux kernel linux-based android operating system dominates smartphone market many countries linux used new york stock exchange supercomputers used desktop laptop computers much criticism linux related lack desktop laptop adoption although 2015 growing unease project perspective security adoption systemd controversial security professionals say rise prominence operating system-level virtualization using linux raised profile attacks kernel linus torvalds reticent add mitigations kernel-level attacks official releases linux 4.12 released 2017 enabled kaslr default effectiveness debated con kolivas former kernel developer tried optimize kernel scheduler interactive desktop use finally dropped support patches due lack appreciation development 2007 interview quit kernel developer con kolivas stated linuxcon 2009 linux creator linus torvalds said linux kernel become bloated huge linuxcon 2014 linux creator linus torvalds said thinks bloat situation better modern pcs lot faster interview german newspaper zeit online november 2011 linus torvalds stated linux become complex concerned developers would able find way software anymore complained even subsystems become complex told publication afraid day error evaluated anymore andrew morton one linux kernel lead developers explains many bugs identified linux never fixed theo de raadt founder openbsd compares openbsd development process linux critics linux desktop frequently argued lack top-selling video games platform holds adoption back september 2015 steam gaming service 1,500 games available linux compared 2,323 games mac 6,500 windows games desktop operating system linux criticized number fronts including another common complaint levelled linux abundance distributions available august 2014 distrowatch lists 285 major distributions linux advocates defended number example freedom choice critics cite large number cause confusion lack standardization linux operating systems alexander wolfe wrote informationweek caitlyn martin linuxdevcenter critical number linux distributions recent decades since established dominance microsoft windows hardware developers often reluctant provide full technical documentation products allow drivers written meant linux user carefully hand pick hardware made system ensure functionality compatibility problems largely addressed one time linux systems required removable media floppy discs cd-roms manually mounted could accessed mounting media automatic nearly distributions development udev companies emperorlinux addressed problems laptop hardware compatibility mating modified linux distributions specially selected hardware ensure compatibility delivery traditional directory structure heritage linux unix roots 1970s criticized inappropriate desktop end users linux distributions like gobolinux moonos proposed alternative hierarchies argued easier end users though achieved little acceptance 2004 microsoft initiated get facts marketing campaign specifically criticized linux server usage particular claimed vulnerabilities windows fewer number linux distributions windows reliable secure linux total cost ownership linux higher due complexity acquisition costs support costs use linux places burden liability businesses linux vendors provide little indemnification coverage addition corporation published various studies attempt prove – factuality heavily disputed different authors claim microsoft comparisons flawed many linux distributors offer indemnification customers internal microsoft reports halloween documents leak presented conflicting views particularly documents 1998 1999 ceded linux ... trusted mission critical applications – due open source code – long term credibility exceeds many competitive oss advanced win32 gui user would short learning cycle become productive linux long term simple experiments indicate linux chance desktop market ... overall respondents felt compelling reason support oss 'offers low total cost ownership tco linux community mixed responses criticisms mentioned criticism led new features better user-friendliness linux community whole reputation resistant criticism writing pc world keir thomas noted time world linux tends anti-critical anybody community dares critical get stomped upon 2015 interview linus torvalds also mentioned tendency linux desktop environment projects blame users instead case criticism
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Operating systems
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juno first juno first ported commodore 64 atari 8-bit family greg hiscott published datasoft 1983 1984 respectively juno first presents set number enemies per level make gallery formation like galaga space invaders instead player ship move forward backward addition left right hunt enemies orientation vertical horizon-oriented tilt style gameplay would re-used later konami shooter axelay player destroys waves enemies finish levels starting formations vary stage stage addition player pick humanoid upon screen red tint happens every enemy player shoots earn player 200 points previous enemy destroyed original score shooting enemy humanoid mode depends stage unofficial hobbyist port—with name original—was made available atari 2600
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Computer architecture
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load shedding load shedding technique used information systems especially web services avoid overloading system making unavailable users idea ignore requests rather crashing system making fail serve request considerations shaping design load shedding algorithms include popular open-source tool defending delays downstream systems finagle
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Web technology
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sap business bydesign sap business bydesign byd cloud enterprise resource planning software cloud erp sold operated software service sap se designed small 20 mio revenue medium-sized enterprises =350 mio revenue software designed provide business processes across application areas financials human resources embedded business analytics mobility e-learning support sap business bydesign built principles service oriented architecture soa integration business capabilities accomplished via messages underlying technology stack multi-tenancy enabled sap netweaver stack leveraging sap in-memory hana database bydesign deployed 144 countries supports 12 languages including simplified chinese japanese korean polish hebrew sap delivers 39 countries either fully localized pre-localized 118 countries sap offers basic tax content addition customers partners create custom country versions using localization toolkit provided sap examples 72 localizations customers partners taiwan malaysia vietnam chile peru sap business bydesign processes grouped application areas interlinked so-called business scenarios scenarios provide business processes span across companies partners departments employees main application areas core business scenarios sap announced sap business bydesign 19 september 2007 event new york previously known code name a1s since initial general available release 2007 so-called feature pack 1.2 enhanced quarterly releases
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Distributed computing architecture
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nintendo dsi system software nintendo dsi system software set updatable firmware versions software frontend nintendo dsi including xl variant video game console updates downloaded via system internet connection allow nintendo add remove features software updates also include changes previous updates user interface nintendo dsi redesigned nintendo ds nintendo ds lite dsi user interface slideable single row icons moving programs fairly snappy icons big enough new touchscreen allow navigation using fingers instead built-in stylus users load dsi first time system snaps shot faces faces fill entire top screen whenever main menu main menu take picture time pressing shoulder buttons camera used also selected within programs power button doubles home button bringing back main screen soft reset nintendo dsi provides built-in applications initially users able access following programs main menu dsi camera dsi sound dsi shop pictochat download play dsi menu akin channel interface nintendo wii new programs downloaded added interface dsi camera application snap shots sorts zany real-time filters users put photos squish heads however subject low resolution actual cameras 0.3mp additionally program recognize shots users taken digital cameras editing dsi sound application thematically similar dsi camera serving sound recorder editor along low bitrate aac music player notable features like excitebike starfox-themed equalizers modulators make user voice sound like robot parakeet dsi shop would serve ds version wii shop channel unlike nintendo previous handheld consoles nintendo ds nintendo ds lite nintendo dsi built music playback support dsi music program split two modes voice recording music playback offer plenty entertainment value tools gimmicks nintendo included recording mode lets users record 18 clips maximum 10 seconds length recorded clip play around various ways example users make clip play backwards forwards isolate small sections using a-b repeat modify speed tone dragging pointer around 2d graph also apply 12 effects clip used transform sound music playback mode also many play options song loaded users change speed tone like recording mode also overlay recordings made recording mode songs point addition nintendo provided set sound effects selected quickly using stylus inserted freely using shoulder buttons unlike built-in dsi camera application would read files generated dsi dsi music application restriction comes files directory structure files stored multi-level directory structure root directory sd card dsi parsed instantly displayed internal directories quick access playback users access features forwarding rewinding volume controls nintendo presumably envisioned dsi music substitute real music player however important drawback ds music application support popular mp3 format instead player supports aac format .mp4 .m4a .3gp filename extensions furthermore compared sony playstation portable difficult interface dsi pc usb port system order transfer music podcasts users need remove sd card plug directly pc one major updates nintendo dsi brings nintendo ds line full network connectivity unlike original nintendo ds nintendo ds lite featured minimal network connectivity download content firmware updates core dsi experience similar wii sony playstation portable consoles example users first power system click dsi shop icon main menu immediately prompted run firmware update nintendo dsi supports wep wpa aes/tkip wpa2 aes/tkip wireless encryption software built-in support use latter two encryption types supported ds ds lite dsi shop application users purchase various dsiware titles cute music blocky interface somewhat similar counterpart wii users permanently login club nintendo account track purchase rewards main shopping interface also lets users add dsi points read dsi shop manual firmware updates dsi shopping experience quite similar wii although big problem dsi shopping slow speed furthermore like previous nintendo ds ds lite nintendo dsi includes web browser version opera browser support html5 canvas object css opacity however limitations features web surfing either platforms whole good experience addition slow download speeds browser difficulty rendering pages example many pages would load completely compatible movie files music files adobe flash multimedia content sites like youtube nintendo dsi collection games applications specifically designed nintendo dsi handheld game console available download via dsi shop known dsiware since games applications specifically targeted nintendo dsi compatible original nintendo ds nintendo ds lite consoles nintendo dsi nintendo first region-locked handheld prevents using certain software released another region unlike original nintendo ds models member nintendo ds line nintendo dsi backward compatible original nintendo ds games cartridge software compatible previous models including original ds games internet browsing photo sharing region-locked later successor nintendo 3ds consoles also adopted approach result nintendo dsi 3ds-specific games locked certain region original ds games still region-free addition dsiware dsi-exclusive although later also run 3ds also dsi-enhanced games containing dsi-exclusive features still played earlier nintendo ds models original ds games run dsi dsi backward compatible game boy advance gba games original ds games require gba slot since dsi lacks slot unlike ds ds lite absence dsi also backward compatible accessories requiring gba slot nintendo ds rumble pak homebrew flash cards designed previous ds models incompatible dsi new cards capable running ds software even dsiware dsi available users transfer purchased dsiware nintendo dsi consoles units dsiware transferred nintendo 3ds although saved data like nintendo dsi nintendo 3ds backward compatible nintendo ds nintendo dsi software list major system updates nintendo dsi gaming platforms nintendo gaming platforms next generation gaming platforms generation
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Operating systems
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nokia pc suite nokia pc suite software package used establish interface nokia mobile devices computers run microsoft windows operating system first release 1997 originally called nokia data suite replaced nokia suite integrated ovi service suite nokia pc suite used transfer music photos applications also used send short message service sms messages act modem connect computer internet mobile phone connected usb bluetooth infrared older nokia phones lack compatibility later versions pc suite official site supplies table matches phone model recent compatible version latest version nokia pc suite also contains several integrated applications including file manager application installer nokia communication centre data viewer pc suite users also access on-device features e.g battery memory call handling well nokia pc sync functionality earliest devices worked nokia data suite nokia 3110 nokia 6110 nokia 8110 nokia pc suite unimproved replaced nokia next generation phone suite software nokia suite supported platforms addition windows nokia suite drops lotus notes client sync support present nokia pc suite instead requiring user use lotus notes traveler software must installed maintained lotus notes server synchronization using pc suite works phone user pc synchronization phone nokia suite must use third party software backup feature pc suite uses non-documented binary file format .nbu used restore phone proprietary client means data accessed restore working phone third-party programs either commercial free used read file greatly vary amount information retrieve nokia pc sync allows user synchronize contacts calendar notes to-do items e-mails bookmarks files/folders supported nokia mobile phone pc sync 7.0.9.2 contained major bug truncating street addresses edited pc run one line synchronized back phone possible lose large parts contacts address information due issue nokia pc suite unable add update maps voices nokia maps application requires nokia map loader nokia suite require microsoft windows .net framework installed however possible download maps nokia maps without need nokia map loader nokia suite pointing web browser directly map files nokia maps server
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Operating systems
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bitarmor bitarmor systems inc. firm based gateway center downtown pittsburgh pennsylvania founded 2003 two carnegie mellon university alumni bitarmor sold software-based encryption data management technologies company mainly focused industries required protection sensitive data retail education health care bitarmor primary product bitarmor datacontrol software solution combined full disk encryption persistent file encryption technology company completed 5 million round venture capital funding may 2009 bitarmor used venture capital fund development efforts expand marketing sales time round financing bitarmor employed 35 people bitarmor acquired trustwave january 2010 order strengthen latter pci services
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Computer security
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matthew garrett matthew garrett technologist programmer free software activist major contributor series free software projects including linux gnome debian ubuntu red hat recipient free software award free software foundation work secure boot uefi linux kernel garrett states born galway ireland phd genetics university cambridge author several articles drosophila melanogaster i.e. fruit fly genetics garrett contributor gnome debian linux projects early contributor ubuntu initial member ubuntu technical board worked contractor canonical ltd. worked red hat canonical ltd. red hat garrett worked power management linux red hat garrett also worked issues relating secure boot uefi linux kernel preserve users ability run operating system choosing hardware supporting secure boot work eventually led awarded 2013 fsf free software award garrett worked cloud computing platform company coreos cited press expert cloud computing issues since 28 january 2017 working google recipient free software award free software foundation work secure boot uefi linux kernel garrett strong advocate software freedom compliance gnu general public license gpl linux kernel example garrett filed complaint us customs fusion garage due violations gpl october 2014 garrett stated blog would longer contribute linux kernel changes relating intel hardware response intel pulling ads gamasutra gamergate controversy however intel took steps demonstrate commitment diversity way appreciated edited post reflect happy resume working
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Operating systems
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cfq completely fair queuing cfq i/o scheduler linux kernel written 2003 jens axboe cfq places synchronous requests submitted processes number per-process queues allocates timeslices queues access disk length time slice number requests queue allowed submit depends i/o priority given process asynchronous requests processes batched together fewer queues one per priority cfq explicit anticipatory i/o scheduling achieves effect good aggregate throughput system whole allowing process queue idle end synchronous i/o thereby anticipating close i/o process considered natural extension granting i/o time slices process february 2003 andrea arcangeli put forward idea stochastic fair queueing i/o scheduler jens axboe implemented jens axboe made improvements first implementation calling new version completely fair queueing scheduler produced patch apply 2.5.60 development series kernel cfq i/o scheduler first integrated mainline kernel optional i/o scheduler possible change scheduler boot time 'elevator parameter kernel red hat enterprise linux 4 used i/o scheduler default even though used kernel based 2.6.9 second release cfq scheduler dubbed cfqv2 included 2.6.10 improvements include better responsiveness elimination starvation issues present earlier version scheduler also switchable run time modifying /sys/block/ block_device /queue/scheduler variable sysfs filesystem cfq scheduler moved new time sliced design dubbed cfqv3 among things implements ioprio_get 2 ioprio_set 2 allows user set per-process i/o priorities usually using ionice 1 command although using nice 1 also modifies i/o priorities somewhat cfq became default scheduler replacing anticipatory scheduler
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Operating systems
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netcat netcat often abbreviated nc computer networking utility reading writing network connections using tcp udp command designed dependable back-end used directly easily driven programs scripts time feature-rich network debugging investigation tool since produce almost kind connection user could need number built-in capabilities list features includes port scanning transferring files port listening used backdoor original netcat features include rewrites like gnu openbsd support additional features example openbsd nc supports tls nc mail.server.net 25 full response including http headers dumped standard output file accessed via web browser nowiki http //servername:8080/ /nowiki netcat serves file first client connects exits also provides content length browsers expect work fine lan may potentially fail kind firewall between. versions netcat like netcat-traditional debian 8.6 need specify -p port number nc -vzu 192.168.0.1 nowiki 80-90 /nowiki note udp tests always show open test useful shell access server tested know whether firewall blocking specific udp port server listening host i.e server whose port needs checked following sending host following – note codice_1 hostname listening host text typed sending host type something hit enter displayed also listening host udp port 4172 open open get error connection refused caveat machines ipv6 may default ip version use codice_2 thus host specified hostname contacted using ipv6 user might know ports may appear closed test even though would open using ipv4 difficult notice may cause false impression port blocked actually open force use ipv4 using adding codice_3 options codice_4 commands echo 0 message nc -w 1 -u loggerhost 514 uncommon use codice_2 port scanning netcat considered best tool job sufficient advanced tool nmap codice_6 parameter prevents dns lookup codice_7 makes codice_4 receive data server codice_9 makes connection timeout 1 second inactivity another useful behaviour using codice_2 proxy ports hosts redirected look example port 12345 represents request starts codice_4 server port 12345 connections get redirected codice_12 web browser makes request codice_4 request sent google response sent web browser pipes unidirectional worked around named pipe redirect input output codice_14 option may also used codice_15 implementation using named pipe reliable method using codice_14 option provides one-shot proxy another useful feature proxy ssl connections way traffic viewed wire sniffing applications wireshark accomplished unixes utilizing codice_17 codice_2 codice_19 codice_2 used make process network server listen port pipe input receives process codice_21 option spawns executable input output redirected via network socket example possible expose bourne shell process remote computers computer ip address 192.168.1.2 run command computer network one could run codice_4 command way codice_21 option used create rudimentary backdoor administrators perceive risk thus allow codice_2 computer ncat similar tool netcat provided nmap suite ncat n't built code “ traditional ” netcat implementation ncat definitely based netcat spirit functionality codice_29 user host1 ncat -l 9899 outputfile user host2 ncat host1 9899 inputfile user host1 ncat -l 9899 inputfile user host2 ncat host1 9899 outputfile suppose ssh tunnel want copy file remote machine could codice_32 directly opens another connection goal re-use existing connection use netcat ssh add codice_33 port forwarding sending everything port 31000 remote machine port local machine extra overhead tcp takes care error correction ssh already encrypted pipe original version netcat unix program last version 1.10 released march 1996 several implementations posix systems including rewrites scratch like gnu netcat openbsd netcat latter supports ipv6 tls openbsd version ported freebsd base windows/cygwin mac os x comes netcat installed osx 10.13 users use macports install variant dos version netcat called ntool included freedos package group networking based wattcp stack licensed european union public licence version 1.1 known ports embedded systems includes versions windows ce named netcat 4 wince iphone busybox includes default lightweight version netcat solaris 11 includes netcat implementation based openbsd netcat socat complex variant netcat larger flexible options must configured given task february 1 2016 santiago zanella-beguelin microsoft vulnerability research issued security advisory regarding composite diffie-hellman parameter hard-coded openssl implementation socat implausibility composite might unintentionally introduced prime number required led suspicion sabotage introduce backdoor software vulnerability socat bug affected version 1.7.3.0 2.0.0-b8 corrected following releases 1.7.3.1 2.0.0-b9 cryptcat version netcat integrated transport encryption capabilities middle 2005 nmap announced another netcat incarnation called ncat features new possibilities connection brokering tcp/udp redirection socks4 client server support ability chain ncat processes http connect proxying proxy chaining ssl connect/listen support ip address/connection filtering like nmap ncat cross-platform systems modified versions similar netcat utilities go command name codice_4 codice_15 codice_38 codice_39 codice_40 codice_41 codice_42
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Computer security
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structured stream transport computer networking structured stream transport sst experimental transport protocol provides ordered reliable byte stream abstraction similar tcp enhances optimizes stream management permit applications use streams much fine-grained fashion feasible tcp streams
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Internet protocols
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spanish cybersecurity research conference spanish cybersecurity research conference spanish jornadas nacionales de investigación en ciberseguridad jnic scientific congress works meeting point different actors working field cybersecurity research universities technological research centres companies public authorities exchange knowledge experience shared goal strengthening research cybersecurity field national level need run kind conferences identified drafting summary report feasibility study design network centers excellence r cybersecurity consensus participants strategic plan spanish network excellence cybersecurity research included measure 17 creation national cybsersecurity r d+i conferences intended scientific meeting point network excellence particular research ecosystem general could demonstrate capacities terms knowledge talent terms research findings potential transference market equally measure 12 study proposed design open call proposals mechanisms evaluate select candidates order grant awards acknowledgement research excellence edition conferences organised institution selected according procedure laid regulation jnic organising committee named based regulations established jnic general chair committee representative organising institution responsible event spanish national cybersecurity institute incibe mission support research cybersecurity strengthening cybersecurity sector participates organization conference aim converting jnic scientific forum excellence national cybersecurity field promotes innovation first time 2017 edition complete technological transfer program designed instrument bring final users companies organisms etc contact researchers order solve cybersecurity problems currently unresolved formulated scientific challenges good reception success participation new initiative challengers research teams expected program continue grow transfer track part jnic future editions
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Computer security
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iqnavigator iqnavigator provides services procurement solutions vendor management system vms managed services offerings 2010 iqnavigator recognized leading services procurement software vendor forrester research inc. forrester wave™ services procurement q3 2010 september 2010 forrester indicated iqnavigator provides all-around excellent solution privately funded iqnavigator inc founded april 1999 focuses helping companies achieve competitive advantage talent management company headquarters denver colorado london england along satellite locations throughout europe asia iqnavigator vendor management system saas platform accessed 100 countries daily iqnavigator clients manage billions spend contingent labor outside services iqnavigator offers ability create custom report fields including customer defined fields reports either run real-time scheduled run predefined bases weekly monthly etc. iqnavigator offers variety mobile computing features including time entry approvals sourcing real-time access statistics interactive reports data views features available blackberry iphone ipad android devices
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Distributed computing architecture
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nessus software nessus proprietary vulnerability scanner developed tenable inc. nasdaq tenb examples vulnerabilities exposures nessus scan include nessus scans cover wide range technologies including operating systems network devices hypervisors databases web servers critical infrastructure results scan reported various formats plain text xml html latex results also saved knowledge base debugging unix scanning automated use command-line client exist many different commercial free open source tools unix windows manage individual distributed nessus scanners nessus provides additional functionality beyond testing known network vulnerabilities instance use windows credentials examine patch levels computers running windows operating system nessus also support configuration compliance audits scada audits pci compliance nessus project started renaud deraison 1998 provide internet community free remote security scanner october 5 2005 tenable network security company renaud deraison co-founded changed nessus 3 proprietary closed source license nessus 2 engine minority plugins still gpl leading forked open source projects based nessus like openvas porz-wahn today product still exists two formats limited free version full-feature paid subscription option nessus available linux windows mac os x. tenable inc. went public july 26 2018 twenty years nessus ’ creation
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Computer security
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malwarebytes software malwarebytes formerly malwarebytes anti-malware abbreviated mbam anti-malware software microsoft windows macos android ios finds removes malware made malwarebytes corporation first released january 2006 available free version scans removes malware started manually paid version additionally provides scheduled scans real-time protection flash-memory scanner malwarebytes formerly known malwarebytes anti-malware primarily scanner scans removes malicious software including rogue security software adware spyware malwarebytes scans batch mode rather scanning files opened reducing interference another on-demand anti-malware software also running computer malwarebytes available free premium paid version free version run manually user desired whereas paid version perform scheduled scans automatically scan files opened block ip addresses malicious web sites scan services programs device drivers currently use december 8 2016 malwarebytes inc. released version 3.0 general public includes protection malware ransomware exploit malicious websites november 2 2009 malwarebytes accused rival iobit incorporating database malwarebytes anti-malware several products vendors named security software iobit security 360 iobit denied accusation stated database based user submissions sometimes signature names malwarebytes get placed results said time filter signature names similar malwarebytes iobit also stated malwarebytes convincing proof promised databases stolen declaration iobit malwarebytes replied convinced argument iobit malwarebytes claims served dmca infringement notices cnet download.com majorgeeks order download sites remove iobit software iobit said version 1.3 database updated address accusations intellectual property theft made earlier malwarebytes vonteera adware uses stolen certificates disables anti-malware virus protection malwarebytes malwarebytes listed solution eliminating threat february 2 2016 project zero announced four vulnerabilities malwarebytes flagship product including lack server-side encryption update files lack proper payload signing within encrypted data combination allowed attacker recompile encrypted payload exploits malwarebytes responded one day disclosure blog article detailing extreme difficulty executing attacks well revealing announced server-side encryption issues resolved within days private disclosure outstanding time project zero published research malwarebytes also published information protect current users patch released event also resulted establishment formal bug bounty program malwarebytes offers 1000 per disclosure depending severity exploitability
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Computer security
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lords time lords time interactive fiction computer game designed sue gazzard released level 9 computing 1983 originally purely textual adventure 8 bit microcomputers game later released part time magik compilation graphics added floppy disk versions like level 9 adventures time written in-house a-code language platform-independent – implementation virtual machine allowed quick porting across platforms anonymous hero game controlled player appears computer programmer contemporary times start game hero contacted father time sends hero quest recover nine treasures order defeat machinations evil time lords game divided 9 eras time including starting section hero living room 20th century ice age age dinosaurs dark ages future middle ages tudor england roman empire due meddling time lords anachronisms abound example cavemen found living era dinosaurs access nine different eras via grandfather clock turns time machine disguise game re-released 1988 part time magik compilation alongside red moon price magik although positioned within compilation first part trilogy real connection latter two opposed sister compilation release silicon dreams three games form trilogy reception lords time positive crash reviewing spectrum version declared find impossible justly describe brilliant adventure lords time really computer video games magazine multiformat review claimed ..the game light-hearted one fun play difficult progress suspect take rather long time complete could ask personal computer games rated pcg hit
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Computer architecture
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database theory database theory encapsulates broad range topics related study research theoretical realm databases database management systems theoretical aspects data management include among areas foundations query languages computational complexity expressive power queries finite model theory database design theory dependency theory foundations concurrency control database recovery deductive databases temporal spatial databases real time databases managing uncertain data probabilistic databases web data research work traditionally based relational model since model usually considered simplest foundational model interest corresponding results data models object-oriented semi-structured models recently graph data models xml often derivable relational model central focus database theory understanding complexity power query languages connection logic starting relational algebra first-order logic equivalent codd theorem insight important queries graph reachability expressible language powerful language based logic programming fixpoint logic datalog studied another focus foundations query optimization data integration work studied conjunctive queries admit query optimization even constraints using chase algorithm main research conferences area acm symposium principles database systems pods international conference database theory icdt
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Databases
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native cloud application native cloud application nca type computer software natively utilizes services infrastructure cloud computing providers amazon ec2 force.com microsoft azure ncas exhibit combined usage three fundamental technologies
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Distributed computing architecture
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swfaddress swfaddress open-source javascript library enables adobe flash/flex javascript/ajax websites web applications support deep linking practice enables users link specific section page content importance rich internet application platforms provide single url access specific content user navigation within content uniquely identified shared means url developer content integrates swfaddress users able use standard browser navigation functionality share bookmark unique urls represent currently displayed section state content library commonly used flash websites web applications available deep linking javascript library flash web swfaddress found used 100,000 websites 2011 swfaddress uses hash portion url interact web browsers simulate page navigation works two ways library built integrate free google analytics web analytics system order record page view statistics track popularity individual pages viewer navigates virtual pages states content also integrates popular swfobject javascript library automatically enable deep linking content loaded swfaddress works major web browsers major operating systems integrated flash content written outdated actionscript 1 recent actionscript 2 latest actionscript 3
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Web technology
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verinice verinice free open source information security management system isms application help creating maintaining systems information security management verinice written maintained primarily german company named sernet service network gmbh verinice licensed gnu general public license version 3 later main users usually small medium companies big enterprises government agencies germany verinice recommended verinice supports operating systems windows linux os x licensed baseline protection catalogs federal office information security
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Computer security
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sybil attack sybil attack attacker subverts reputation system peer-to-peer network creating large number pseudonymous identities uses gain disproportionately large influence named subject book sybil case study woman diagnosed dissociative identity disorder name suggested 2002 brian zill microsoft research term pseudospoofing previously coined l. detweiler cypherpunks mailing list used literature peer-to-peer systems class attacks prior 2002 term gain much influence sybil attack sybil attack computer security attack wherein reputation system subverted forging identities peer-to-peer networks reputation system vulnerability sybil attack depends cheaply identities generated degree reputation system accepts inputs entities chain trust linking trusted entity whether reputation system treats entities identically evidence showed large-scale sybil attacks could carried cheap efficient way extant realistic systems bittorrent mainline dht entity peer-to-peer network piece software access local resources entity advertises peer-to-peer network presenting identity one identity correspond single entity words mapping identities entities many one entities peer-to-peer networks use multiple identities purposes redundancy resource sharing reliability integrity peer-to-peer networks identity used abstraction remote entity aware identities without necessarily knowing correspondence identities local entities default distinct identity usually assumed correspond distinct local entity reality many identities may correspond local entity adversary may present multiple identities peer-to-peer network order appear function multiple distinct nodes adversary may thus able acquire disproportionate level control network affecting voting outcomes context human online communities multiple identities sometimes known sockpuppets notable sybil attack conjunction traffic confirmation attack launched tor anonymity network several months 2014 unknown perpetrators validation techniques used prevent sybil attacks dismiss masquerading hostile entities local entity may accept remote identity based central authority ensures one-to-one correspondence identity entity may even provide reverse lookup identity may validated either directly indirectly direct validation local entity queries central authority validate remote identities indirect validation local entity relies already accepted identities turn vouch validity remote identity question identity-based validation techniques generally provide accountability expense anonymity undesirable tradeoff especially online forums wish permit censorship-free information exchange open discussion sensitive topics validation authority attempt preserve users anonymity refusing perform reverse lookups approach makes validation authority prime target attack alternatively authority use mechanism knowledge user real identity verification unidentified person physical presence particular place time enforce one-to-one correspondence online identities real-world users sybil prevention techniques based connectivity characteristics social graphs also limit extent damage caused given sybil attacker preserving anonymity though techniques prevent sybil attacks entirely may vulnerable widespread small-scale sybil attacks examples prevention techniques sybilguard advogato trust metric also sparsity based metric identify sybil clusters distributed p2p based reputation system alternatively proof work used make sybil attacks expensive i2p implementation kademlia modified mitigate kademlia vulnerabilities sybil attacks
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Computer security
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articulatory speech recognition articulatory speech recognition means recovery speech forms phonemes syllables words acoustic signals help articulatory modeling extra input articulatory movement data speech recognition automatic speech recognition acoustic speech recognition means recovery speech acoustics sound wave articulatory information extremely helpful acoustic input low quality perhaps noise missing data
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Computational linguistics
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invincea invincea suite endpoint protection products formerly sold sophos invincea inc. originally secure command llc venture backed software company provided malware threat detection prevention pre-breach forensic intelligence acquired sophos 2017 sophos ended immediate end sale invincea products april 2018 founded 2006 anup ghosh company headquartered fairfax virginia major investors include dell ventures new atlantic ventures grotech ventures aeris capital harbert venture partners 2012 invincea used 21 million grant darpa improve security us military android-based devices tablet pcs smart phones invincea software secures data unauthorized access protects device malicious applications june 2013 dell announced oem partnership invincea began shipping new endpoint security solution dubbed “ dell data protection protected workspace ” commercial tablets pcs worldwide december 2013 invincea acquired sandboxie undisclosed amount sandboxie pioneer windows containment sandboxing market making logical addition invincea ’ technology portfolio may 2016 invincea launched x invincea x protects endpoints detecting blocking known unknown malware—without signatures real-time x combines deep learning advanced form machine learning behavioral analysis isolation technology one lightweight agent february 2017 invincea acquired sophos security software hardware company august year subsidiary invincea labs renamed two six labs january 2018 sophos announced invincea would integrated intercept x end-point security product april 16 2018 announced immediate end sale invincea-branded products support maintenance available existing contracts december 31st 2019 point support maintenance invincea products cease april 16 2018 sophos announced would longer selling invincea-related products although would continue support existing sales end 2019
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Computer security
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openezx openezx project tries gather information linux based motorola ezx phone platform tries provide 100 free software stack phones especially way avoid proprietary filesystem and/or device drivers also aims provide current 2.6.x kernel required hardware support ezx phones currently supported phones
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Operating systems
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windows workflow foundation windows workflow foundation wf microsoft technology provides api in-process workflow engine rehostable designer implement long-running processes workflows within .net applications current version wf released part .net framework version 4.5 referred wf45 workflow defined series distinct programming steps phases step modeled wf activity .net framework provides library activities writeline activity writes text console form output custom activities also developed additional functionality activities assembled visually workflows using workflow designer design surface runs within visual studio designer also hosted applications encapsulating programming functionality activities allows developer create manageable applications component execution developed common language runtime object whose execution managed workflow runtime windows workflow foundation used create applications execute ordered business process steps needed approve document hire candidate position make purchase processes execute short amount time typically long-running application need shut conserve memory steps typically business processes modeled workflows following features workflows created either defined xaml extensible application markup language using workflow designer assembled programmatically .net language c vb.net designer used activities assembled workflow designer canvas dragging toolbox workflow arguments variables also created assigned within designer workflow assembled code activities instantiated like clr objects assembled collections single parent activity usually sequence flowchart single parent activity executed using workflowapplication workflowinvoker runs workflow term workflow usually refers root activity executed host workflows use out-of-box activities custom activities out-of-box activities include flow control activities dowhile flowchart-related activities flowdecision wcf messaging activities send primitive activities perform simple tasks like assign writeline custom activities user-created clr objects derive class system.activitiesactivity provide declarative functionality allowing developer define execution behavior activity code custom activities benefit custom activity designer associated enhance visual authoring experience visual studio ide
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Operating systems
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csg 65ce02 csg 65ce02 8/16-bit microprocessor developed commodore semiconductor group 1988 member mos technology 6502 family developed cmos wdc 65c02 released western design center 1983 65ce02 built 2 µm cmos process instead original 6502 8 µm nmos technology making chip smaller thus less expensive well using much less power addition changes made 65c02 65ce02 also included improvements processor pipeline allow one-byte instructions complete 1 cycle rather 6502 variants minimum 2 cycles also removed 1 cycle delays crossing page boundaries changes improved performance much 25 clock speed changes included addition third index register z along addition modification number instructions use register zero-page first 256 bytes memory used pseudo-registers could moved page main memory using b ase page register stack register widened 8 16-bits using similar page register sph stack pointer high allowing stack moved page one grow larger sizes 65ce02 basis system chip csg 4501 developed unreleased commodore 65 65ce02 later used a2232 serial port card amiga computer appears seen use original 6502 designed era microcomputers existed microprocessors used basis simpler systems like smart terminals desktop calculators many different industrial controller systems also era memory devices generally based static ram expensive low memory density reasons ability handle large amounts memory required many processors operating modes worked small portions larger address space order offer higher performance case 6502 used first memory page zero page provide faster access second page page one hold 256-byte stack late 1970s original mos technology team designed 6502 broken bill mensch moved arizona set western design center wdc provide 6502-based design services around 1981 main licensees 6502 design rockwell semiconductor gte signetics began redesign effort mensch led wdc 65c02 mainly cmos implementation original nmos 6502 used 10 20 times less power also included number new instructions help improve code density certain applications new instructions included codice_1 increment decrement accumulator codice_2 write zero memory location codice_3 jump branch-style 1-byte relative address 65c02 also fixed number minor bugs original 6502 design 65ce02 improved version 65c02 expands memory model make suitable system large amounts main memory adds 8-bit b register base page offsets zero page location memory b set zero power-up reset initially works exactly like 6502 however value placed b register using codice_4 transfer b zero page moves new location significant use feature allow small routines fit within 256 bytes page use zero-page addressing known base page addressing makes code smaller addresses longer second byte also makes code run faster second byte fetched memory 65ce02 also extends stack original 256-bytes page one theory entire address space adding another 8-bit register like b register sph stack pointer high normally works like b offsetting base address stack page one selected page otherwise continues work maximum size one page 256 bytes like b startup reset sph set 01 works exactly like 65c02 however new stack extend bit status register set using new codice_5 instructions stack pointer becomes true 16-bit value value register added value original sp known spl stack pointer low produce 16-bit pointer bottom stack unlike b register however sph used stack extend bit status register set cleared startup reset using bit allows pipeline avoid construct full 16-bit address needed saving cycles stack accesses mode explicitly set using new codice_5 instructions clear set flag 65ce02 also adds new index register z set zero startup reset meaning store-z-to-memory instruction codice_2 works like 65c02 instruction means store-zero-to-memory allows unmodified 65c02 code run 65ce02 number instructions added modified allow access z register among codice_8 load value memory codice_9 transfer value accumulator codice_10 push pull z stack codice_11 increment decrement codice_12 compare value z value memory 65c02 added codice_3 branch always essentially codice_14 used branch-style 8-bit relative address instead absolute 16-bit address could simulated original 6502 using codice_15 branch overflow clear reasons almost always clear 6502 longer true 65c02 certain operations correctly set flag unknown reasons 65ce02 changed mnemonic codice_16 also added codice_17 instruction branch subroutine uses relative addressing mode codice_18 jump subroutine addition added 16-bit addressing word relative existing branch instructions previously branches could move backward 128 locations forward 127 based signed 8-bit value relative address 65ce02 could -32768 +32767 locations following branch 16-bit value previously perform long branch one normally use codice_14 branch n't want instance one wanted branch address 1234 accumulator zero one would codice_20 meaning want skip 3-byte codice_14 accumulator zero 65ce02 reduced something like codice_22 thereby making code obvious removing two bytes instructions removing need lost cycles fetching running branch however still uses relative addressing relative address calculated programmer assembler another addition system number word instructions carried operations 16-bit data included codice_23 increment decrement value memory codice_24 perform arithmetic shift left word rotate left word finally minor changes include addition codice_25 bit-shift right 6502 left shift codice_26 instruction performs two complement negation accumulator codice_27 variation codice_28 return subroutine returns address offset stack instead top avoiding need explicitly codice_29 anything routine added ran system also added new addressing mode used base address stack basis indirect addressing major oddity original 6502 one-byte instructions like codice_30 still took two cycles complete allowed simplifications pipeline system next byte memory fetched operation decoded meaning next byte fetched matter instructions byte would part whole operand could fed now-decoded instruction instruction required one byte processor read following byte next instruction however way feed back first stage pipeline decode case fetched byte discarded re-read feed decoder wastes cycle although led number instructions slower could feature retained 65c02 although whether order retain pipeline simplicity cycle timing explained available sources maintaining cycle compatibility requirement 65ce02 new fabrication processes made extra circuitry pipeline non-issue pipeline re-arranged correctly handle one-byte instructions result 65ce02 recover faster engagement sync signal reduces minimum instruction execution time 2 cycles 1 cycle improvements allow 65ce02 execute code 25 faster previous 65xx models fabricated using 2 µm cmos technology allowing lower power operation compared previous nmos hmos versions 65xx family housed 40-pin dip pin compatible 6502 4510 system package sip variant 65ce02 includes two 6526 cia i/o port controllers custom mmu expand address space 20 bit 1 megabyte housed 84-pin plcc 4510 used unreleased commodore 65 home computer unreleased commodore cdtv cost-reduced revision 65ce02 used commodore a2232 serial port card amiga computer
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Computer architecture
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mcst-r1000 mcst r1000 64-bit microprocessor developed moscow center sparc technologies mcst fabricated tsmc development microprocessor designated mcst-4r
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Computer architecture
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ahi amiga ahi ahi audio system retargetable audio subsystem amigaos morphos aros created martin blom mid-1990s allow standardized operating system support audio hardware native amiga sound chip example 16-bit sound cards ahi offers improved functionality available amigaos audio device driver seamless audio playback user selected audio device applications supported ahi standardized functionality audio recording efficient software mixing routines combining multiple sound channels thus overcoming four channel hardware limit original amiga chipset also incorporated unique mode produced 14-bit playback using amiga chipset combining two 8-bit channels set different volumes first official release ahi 1996 ahi became widely supported standard audio hardware audio software amiga systems officially included later operating system releases author stated referring software correct term 'ahi audio system 'ahi 'audio hardware interface term sometimes used press
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Operating systems
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servicenow servicenow inc. service-now 2011 american cloud computing company headquarters santa clara california founded 2004 fred luddy servicenow listed new york stock exchange constituent russell 1000 index servicenow founded glidesoft inc. 2003 fred luddy previous cto software companies peregrine systems remedy corporation later incorporated california 2004 luddy previously served chief technology officer peregrine systems enterprise software company based san diego 2002 founding company luddy intended provide services previously available defunct peregrine systems mid-2005 luddy employee concentrated developing software company would offer came first hires five people raising venture financing jmi equity 2006 company changed name servicenow 2007 servicenow reported annual revenue opened first silicon valley office san jose 2007 also first year company went cash flow positive company 275 employees san diego chicago new york atlanta london frankfurt offices well partnership accenture 100 servicenow consultants time company known service-now april 2011 company named frank slootman chief executive officer june 2012 servicenow became publicly traded company following ipo shortly thereafter company relocated headquarters san diego santa clara california first technology company taken public morgan stanley since facebook october 2017 company acquired san diego human-centered design firm telepathy founded 2001 acquisition doubled size servicenow internal design agency design experience organization october 2017 servicenow acquired skygiraffe enterprise mobility platform consequently formed basis servicenow mobile platform offering released march 2019 skygiraffe founded boaz hecht itay braun 2012 headquartered california r israel april 2018 servicenow acquired vendorhawk software-as-service-management company may 2018 servicenow acquired parlo artificial intelligence natural language understanding workforce solution october 2018 servicenow acquired friendlydata company specializing form natural language processing enables queries asked plain language 2019 servicenow acquired appsee ltd. analytics startup helped developers understand users interact mobile apps servicenow software-as-a-service provider providing technical management support service management operations large corporations including providing help desk functionality company core business revolves around management incident problem change operational events fee model based cost per user seat per month cost ranging
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Distributed computing architecture
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side-channel attack computer security side-channel attack attack based information gained implementation computer system rather weaknesses implemented algorithm e.g cryptanalysis software bugs timing information power consumption electromagnetic leaks even sound provide extra source information exploited side-channel attacks require technical knowledge internal operation system although others differential power analysis effective black-box attacks rise web 2.0 applications software-as-a-service also significantly raised possibility side-channel attacks web even transmissions web browser server encrypted e.g. https wifi encryption according researchers microsoft research indiana university many powerful side-channel attacks based statistical methods pioneered paul kocher attempts break cryptosystem deceiving coercing people legitimate access typically considered side-channel attacks see social engineering rubber-hose cryptanalysis general classes side channel attack include cases underlying principle physical effects caused operation cryptosystem side provide useful extra information secrets system example cryptographic key partial state information full partial plaintexts forth term cryptophthora secret degradation sometimes used express degradation secret key material resulting side-channel leakage works monitoring security critical operations aes t-table entry modular exponentiation multiplicand accesses attacker able recover secret key depending accesses made made victim deducing encryption key also unlike side-channel attacks method create fault ongoing cryptographic operation invisible victim 2017 cache-based vulnerabilities discovered cpus dubbed meltdown spectre allow attacker leak memory contents processes operating system timing attack watches data movement cpu memory hardware running cryptosystem algorithm simply observing variations long takes perform cryptographic operations might possible determine entire secret key attacks involve statistical analysis timing measurements demonstrated across networks power-analysis attack provide even detailed information observing power consumption hardware device cpu cryptographic circuit attacks roughly categorized simple power analysis spa differential power analysis dpa fluctuations current also generate radio waves enabling attacks analyze measurements electromagnetic emanations attacks typically involve similar statistical techniques power-analysis attacks historical analogues modern side-channel attacks known recently declassified nsa document reveals far back 1943 engineer bell telephone observed decipherable spikes oscilloscope associated decrypted output certain encrypting teletype according former mi5 officer peter wright british security service analyzed emissions french cipher equipment 1960s 1980s soviet eavesdroppers suspected planted bugs inside ibm selectric typewriters monitor electrical noise generated type ball rotated pitched strike paper characteristics signals could determine key pressed power consumption devices causes heating offset cooling effects temperature changes create thermally induced mechanical stress stress create low level acoustic emissions operating cpus 10 khz cases recent research shamir et al suggested information operation cryptosystems algorithms obtained way well acoustic cryptanalysis attack surface cpu chip cases cpu package observed infrared images also provide information code executed cpu known thermal-imaging attack optical side-channel attack examples include gleaning information hard disk activity indicator reading small number photons emitted transistors change state side-channel attacks rely relationship information emitted leaked side channel secret data countermeasures fall two main categories 1 eliminate reduce release information 2 eliminate relationship leaked information secret data make leaked information unrelated rather uncorrelated secret data typically form randomization ciphertext transforms data way undone cryptographic operation e.g. decryption completed first category displays special shielding lessen electromagnetic emissions reducing susceptibility tempest attacks commercially available power line conditioning filtering help deter power-monitoring attacks although measures must used cautiously since even small correlations remain compromise security physical enclosures reduce risk surreptitious installation microphones counter acoustic attacks micro-monitoring devices cpu power-draw thermal-imaging attacks another countermeasure still first category jam emitted channel noise instance random delay added deter timing attacks although adversaries compensate delays averaging multiple measurements generally using measurements analysis amount noise side channel increases adversary needs collect measurements another countermeasure first category use security analysis software identify certain classes side channel attacks found design stages underlying hardware timing attacks cache attacks identifiable certain commercially available security analysis software platforms allow testing identify attack vulnerability well effectiveness architectural change circumvent vulnerability comprehensive method employ countermeasure create secure development lifecycle hardware includes utilizing available security analysis platforms respective stages hardware development lifecycle case timing attacks targets whose computation times quantized discrete clock cycle counts effective countermeasure design software isochronous run exactly constant amount time independently secret values makes timing attacks impossible countermeasures difficult implement practice since even individual instructions variable timing cpus one partial countermeasure simple power attacks differential power-analysis attacks design software pc-secure program counter security model pc-secure program execution path depend secret values words conditional branches depend public information even though multiply operations draw power nop practically cpus using constant execution path prevents operation-dependent power differences differences power choosing one branch another leaking secret information architectures instruction execution time data-dependent pc-secure program also immune timing attacks another way code non-isochronous modern cpus memory cache accessing infrequently used information incurs large timing penalty revealing information frequency use memory blocks cryptographic code designed resist cache attacks attempts use memory predictable fashion accessing input outputs program data according fixed pattern example data-dependent table lookups must avoided cache could reveal part lookup table accessed partial countermeasures attempt reduce amount information leaked data-dependent power differences operations use power correlated number 1 bits secret value using constant-weight code using fredkin gates dual-rail encoding reduce leakage information hamming weight secret value although exploitable correlations likely remain unless balancing perfect balanced design approximated software manipulating data complement together several secure cpus built asynchronous cpus global timing reference cpus intended make timing power attacks difficult subsequent research found timing variations asynchronous circuits harder remove typical example second category decorrelation technique known blinding case rsa decryption secret exponent formula_1 corresponding encryption exponent formula_2 modulus formula_3 technique applies follows simplicity modular reduction omitted formulas decrypting computing result formula_4 given ciphertext formula_5 system picks random number formula_6 encrypts public exponent formula_2 obtain formula_8 decryption done formula_9 obtain formula_10 since decrypting system chose formula_6 compute inverse modulo formula_3 cancel factor formula_6 result obtain formula_4 actual result decryption attacks require collecting side-channel information operations data controlled attacker blinding effective countermeasure since actual operation executed randomized version data attacker control even knowledge another general countermeasure effective side-channel attacks masking countermeasure principle masking avoid manipulating sensitive value formula_5 directly rather manipulate sharing set variables called shares formula_16 formula_17 formula_18 xor operation attacker must recover values shares get meaningful information
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Computer security
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xtreemfs xtreemfs object-based distributed file system wide area networks xtreemfs outstanding feature full components real failure scenarios including network partitions fault tolerance maintaining posix file system semantics fault-tolerance achieved using paxos-based lease negotiation algorithms used replicate files metadata ssl x.509 certificates support make xtreemfs usable public networks xtreemfs development since early 2007 first public release made august 2008 xtreemfs 1.0 released august 2009 1.0 release includes support read-only replication failover data center replica maps parallel reads writes native windows client 1.1 added automatic on-close replication posix advisory locks mid-2011 release 1.3 added read/write replication files version 1.4 underwent extensive testing considered production-quality improved hadoop integration support ssds added version 1.5 xtreemfs funded european commission ist programme original xtreemfs team founded quobyte inc. 2013 quobyte offers professional storage system commercial product
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Computer file systems
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eagle application server eagle web-based mainframe-powered application server provides direct secure high performance internet access mainframe computer data transactions using real-time transaction processing rather middleware external gateways originally based ibm 3270 environment developed university florida reduce delivery time student record applications engine configured web 1996 removed need screen scraping interface eagle provides direct network access mainframe data transactions web applications talk directly native mainframe resources without complexity expense middleware non-mainframe resources accessed via hooks customized communication programs using xml edi since eagle mainframe computer transaction application pages created internally delivered via web reduces overhead compared external call interfaces resulting considerable performance gains periods peak demand university florida eagle routinely handles 400,000 transactions per day maintaining sub-second response time web defined stateless environment—normally web page requested web page delivered interaction eagle associates pages user handles authentication authorization eagle session management engine protected behind mainframe security eagle awarded patent 6,532,463 state maintenance mechanism
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Web technology
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philip wadler philip lee wadler born april 8 1956 american computer scientist known contributions programming language design type theory particular contributed theory behind functional programming use monads functional programming design purely functional language haskell xquery declarative query language 1984 created orwell programming language wadler involved adding generic types java 5.0 also author paper theorems free gave rise much research functional language optimization see also parametricity wadler received bachelor science degree mathematics stanford university 1977 master science degree computer science carnegie mellon university 1979 completed doctor philosophy computer science carnegie mellon university 1984 thesis entitled listlessness better laziness supervised nico habermann wadler research interests programming languages wadler research fellow programming research group part oxford university computing laboratory st cross college oxford 1983–87 progressively lecturer reader professor university glasgow 1987 1996 wadler member technical staff bell labs lucent technologies 1996–99 avaya labs 1999–2003 since 2003 professor theoretical computer science school informatics university edinburgh wadler editor journal functional programming 1990 2004 wadler currently working new functional language designed writing web applications called links supervised numerous doctoral students completion since 2003 wadler professor theoretical computer science laboratory foundations computer science university edinburgh chair theoretical computer science also member university blockchain technology laboratory h-index 70 24,447 citations google scholar wadler received influential popl paper award 2003 1993 popl symposium paper imperative functional programming jointly simon peyton jones 2005 elected fellow royal society edinburgh 2007 inducted acm fellow association computing machinery acm
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Programming language topics
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associative entity associative entity term used relational entity–relationship theory relational database requires implementation base relation base table resolve many-to-many relationships base relation representing kind entity called informally associative table mentioned associative entities implemented database structure using associative tables tables contain references columns different database tables within database associative junction table maps two tables together referencing primary keys data table effect contains number foreign keys many-to-one relationship junction table individual data tables pk associative table typically composed fk columns associative tables colloquially known many names including association table bridge table cross-reference table crosswalk intermediary table intersection table join table junction table link table linking table many-to-many resolver map table mapping table pairing table pivot table used incorrectly laravel confused correct use pivot table spreadsheets transition table example practical use associative table would assign permissions users multiple users user assigned zero permissions individual permissions may granted one users select-statement junction table usually involves joining main table junction table return list users permissions inserting junction table involves multiple steps first inserting main table updating junction table using foreign keys database automatically dereference values userpermissions table tables
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Databases
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multiuser dos federation multiuser dos federation mdos industry alliance promote growth acceptance multi-user dos-based solutions 286 386 486 computers formed july 1990 idea reduce costs allowing workgroups run dos applications shared pc working terminals workstations 18 february 1991 several members multiuser dos federation issued press release regarding intentions support dpmi mostly dpmi 1.0 products including alloy computer products inc. pc-plus bluebird systems inc. superdos concurrent controls inc. cci multiuser dos digital research inc. dr multiuser dos h computer systems inc. tsx-32 starpath systems inc. vmos/3 software link pc-mos/386 theos software corporation theos intelligent graphics corporation vm/386
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Computer architecture
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rudolf berghammer rudolf berghammer born 1952 oberndorf germany german mathematician works computer science rudolf berghammer worked electrician farbwerke hoechst kelheim 1966 1970 began studying mathematics computer science 1973 tu münchen academic teachers friedrich l. bauer klaus samelson gottfried tinhofer gunther schmidt obtaining diploma 1979 started working assistant mainly gunther schmidt friedrich l. bauer tu münchen obtained award-winning ph.d. 1984 1988 worked assistant gunther schmidt faculty computer science universität der bundeswehr münchen finally got habilitation 1990 since 1993 professor computer-aided program development department computer science university kiel many years served head steering committee international ramics conference series formerly termed relmics rudolf berghammer known work relational mathematics formal methods programming semantics relational methods computer science developed relview system manipulation visualisation relations relational programming instance 2019 coauthor cryptomorphic topological structures computational relation algebraic approach work relates classical neighborhood system approach topology closure operators kernel operators aumann contact relations formulation one approach another done calculus relations article notes contributions relview experiments finite topologies instance set seven elements 9,535,241 topologies tested see § 9 one hobbies mountaineering youth climbed ortler piz bernina noted summits active climber spending several days alps every year
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Programming language topics
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precision time protocol precision time protocol ptp protocol used synchronize clocks throughout computer network local area network achieves clock accuracy sub-microsecond range making suitable measurement control systems ptp currently employed synchronize financial transactions mobile phone tower transmissions sub-sea acoustic arrays networks require precise timing lack access satellite navigation signals ptp originally defined ieee 1588-2002 standard officially entitled standard precision clock synchronization protocol networked measurement control systems published 2002 2008 ieee 1588-2008 released revised standard also known ptp version 2 improves accuracy precision robustness backward compatible original 2002 version according john eidson led ieee 1588-2002 standardization effort ieee 1588 designed fill niche well served either two dominant protocols ntp gps ieee 1588 designed local systems requiring accuracies beyond attainable using ntp also designed applications bear cost gps receiver node gps signals inaccessible ieee 1588 standards describe hierarchical master-slave architecture clock distribution architecture time distribution system consists one communication media network segments one clocks ordinary clock device single network connection either source master destination slave synchronization reference boundary clock multiple network connections accurately synchronize one network segment another synchronization master selected network segments system root timing reference called grandmaster grandmaster transmits synchronization information clocks residing network segment boundary clocks presence segment relay accurate time segments also connected simplified ptp system frequently consists ordinary clocks connected single network boundary clocks used grandmaster elected clocks synchronize directly ieee 1588-2008 introduces clock associated network equipment used convey ptp messages transparent clock modifies ptp messages pass device timestamps messages corrected time spent traversing network equipment scheme improves distribution accuracy compensating delivery variability across network ptp typically uses epoch unix time start 1 january 1970 unix time based coordinated universal time utc subject leap seconds ptp based international atomic time tai ptp grandmaster communicates current offset utc tai utc computed received ptp time synchronization management ptp system achieved exchange messages across communications medium end ptp uses following message types messages categorized event general messages event messages time-critical accuracy transmission receipt timestamp accuracy directly affects clock distribution accuracy sync delay_req pdelay_req pdelay_resp event messages general messages conventional protocol data units data messages importance ptp transmission receipt timestamps announce follow_up delay_resp pdelay_resp_follow_up management signaling messages members general message class ptp messages may use user datagram protocol internet protocol udp/ip transport ieee 1588-2002 uses ipv4 transports extended include ipv6 ieee 1588-2008 ieee 1588-2002 ptp messages sent using multicast messaging ieee 1588-2008 introduced option devices negotiate unicast transmission port-by-port basis multicast transmissions use ip multicast addressing multicast group addresses defined ipv4 ipv6 see table time-critical event messages sync delay_req pdelay_req pdelay_resp sent port number 319 general messages announce follow_up delay_resp pdelay_resp_follow_up management signaling use port number 320 ieee 1588-2008 encapsulation also defined devicenet controlnet profinet domain interacting set clocks synchronize one another using ptp clocks assigned domain virtue contents subdomain name ieee 1588-2002 domainnumber ieee 1588-2008 fields ptp messages receive generate domains allow multiple clock distribution systems share communications medium best master clock bmc algorithm performs distributed selection best candidate clock based following clock properties ieee 1588-2008 uses hierarchical selection algorithm based following properties indicated order ieee 1588-2002 uses selection algorithm based similar properties clock properties advertised ieee 1588-2002 sync messages ieee 1588-2008 announce messages current clock master transmits information regular interval clock considers better master clock transmit information order invoke change master clock current master recognises better clock current master stops transmitting sync messages associated clock properties announce messages case ieee 1588-2008 better clock takes master bmc algorithm considers self-declared quality clocks take network link quality consideration use bmc algorithm ptp selects master source time ieee 1588 domain network segment domain clocks determine offset master let variable formula_1 represent physical time given slave device offset formula_2 time formula_1 defined formula_5 represents time measured slave clock physical time formula_1 formula_7 represents time measured master clock physical time formula_1 master periodically broadcasts current time message clocks ieee 1588-2002 broadcasts per second ieee 1588-2008 10 per second permitted broadcast begins time formula_9 sync message sent master clocks domain clock receiving message takes note local time formula_10 message received master may subsequently send multicast follow_up accurate formula_9 timestamp masters ability present accurate timestamp sync message transmission complete able retrieve accurate timestamp sync transmission network hardware masters limitation use follow_up message convey formula_9 masters ptp capabilities built network hardware able present accurate timestamp sync message need send follow_up messages order accurately synchronize master clocks must individually determine network transit time sync messages transit time determined indirectly measuring round-trip time clock master clocks initiate exchange master designed measure transit time formula_13 exchange begins clock sending delay_req message time formula_14 master master receives timestamps delay_req time formula_15 responds delay_resp message master includes timestamp formula_15 delay_resp message exchanges clock learns formula_9 formula_10 formula_14 formula_15 formula_13 transit time sync message formula_22 constant offset master slave clocks combining two equations find clock knows offset formula_22 transaction correct amount bring agreement master one assumption exchange messages happens period time small offset safely considered constant period another assumption transit time message going master slave equal transit time message going slave master finally assumed master slave accurately measure time send receive message degree assumptions hold true determines accuracy clock slave device ieee 1588-2008 standard lists following set features implementations may choose support
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Internet protocols
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ws-reliability ws-reliability soap-based soap 1.1 soap 1.2 part 1 oasis specification fulfills reliable messaging requirements critical applications web services ws-reliability superseded ws-reliablemessaging soap http sufficient application-level messaging protocol must also guarantee level reliability security specification defines reliability context current web services standards specification designed use combination complementary protocols builds previous experiences e.g. ebxml message service
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Web technology
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make software software development make build automation tool automatically builds executable programs libraries source code reading files called makefiles specify derive target program though integrated development environments language-specific compiler features also used manage build process make remains widely used especially unix unix-like operating systems besides building programs make used manage project files must updated automatically others whenever others change number dependency-tracking build utilities make one widespread primarily due inclusion unix starting pwb/unix 1.0 featured variety tools targeting software development tasks originally created stuart feldman april 1976 bell labs feldman received 2003 acm software system award authoring widespread tool feldman inspired write make experience coworker futilely debugging program executable accidentally updated changes make introduction unix build system commonly consisted operating system dependent make install shell scripts accompanying program source able combine commands different targets single file able abstract dependency tracking archive handling important step direction modern build environments make gone number rewrites including number from-scratch variants used file format basic algorithmic principles also provided number non-standard enhancements posix includes standardization basic features operation make utility implemented varying degrees completeness unix-based versions make general simple makefiles may used various versions make reasonable success gnu make makepp versions bsd make default looking first files named gnumakefile makeppfile bsdmakefile respectively allows one put makefiles use implementation-defined behavior separate locations make typically used build executable programs libraries source code generally though make applicable process involves executing arbitrary commands transform source file target result example make could used detect change made image file source transformation actions might convert file specific format copy result content management system send e-mail predefined set users indicating actions performed make invoked list target file names build command-line arguments make target ... without arguments make builds first target appears makefile traditionally symbolic phony target named make decides whether target needs regenerated comparing file modification times solves problem avoiding building files already date fails file changes modification time stays past changes could caused restoring older version source file network filesystem source files clock timezone synchronized machine running make user must handle situation forcing complete build conversely source file modification time future triggers unnecessary rebuilding may inconvenience users make searches current directory makefile use e.g gnu make searches files order file named one gnumakefile makefile makefile runs specified default target file makefile language similar declarative programming class language necessary end conditions described order actions taken important sometimes confusing programmers used imperative programming one problem build automation tailoring build process given platform instance compiler used one platform might accept options one used another well handled make problem typically handled generating platform-specific build instructions turn processed make common tools process autoconf cmake gyp advanced ng makefile consists rules rule begins textual dependency line defines target followed colon optionally enumeration components files targets target depends dependency line arranged target left hand colon depends components right hand colon common refer components prerequisites target usually rule single unique target rather multiple targets example c .o object file created .c files .c files come first i.e specific object file target depends c source file header files make understand recognize distinguish different kinds files opens possibility human error forgotten extra dependency may immediately obvious may result subtle bugs generated software possible write makefiles generate dependencies calling third-party tools makefile generators automake toolchain provided gnu project automatically dependency line may followed series tab indented command lines define transform components usually source files target usually output prerequisites recent modification time target command lines run gnu make documentation refers commands associated rule recipe first command may appear line prerequisites separated semicolon targets prerequisites command example hello echo hello make decide start topological sorting command line must begin tab character recognized command tab whitespace character space character special meaning problematic since may visual difference tab series space characters aspect syntax makefiles often subject criticism described eric s. raymond one worst design botches history unix unix-haters handbook said using tabs part syntax like one pungee stick traps green berets feldman explains choice caused workaround early implementation difficulty preserved desire backward compatibility first users however gnu make since version 3.82 allows choose symbol one character recipe prefix using .recipeprefix special variable example .recipeprefix command executed separate shell command-line interpreter instance since operating systems use different command-line interpreters lead unportable makefiles instance gnu make default executes commands /bin/sh unix commands like cp normally used contrast microsoft nmake executes commands cmd.exe batch commands like copy available necessarily cp rule may command lines defined dependency line consist solely components refer targets example realclean clean distclean command lines rule usually arranged generate target example file.html newer converted text contents makefile file.txt file.html rule would triggered make updates file.txt following invocation make would typically use rule update file.txt target file.html newer make file.txt command lines one following three prefixes ignoring errors silencing echo alternatively obtained via special targets .ignore .silent microsoft nmake predefined rules omitted makefiles e.g c.obj cc cflags makefile contain definitions macros macros usually referred variables hold simple string definitions like cc=clang macros makefiles may overridden command-line arguments passed make utility environment variables also available macros macros allow users specify programs invoked custom behavior build process example macro cc frequently used makefiles refer location c compiler user may wish specify particular compiler use new macros simple variables traditionally defined using capital letters macro definition macro used expanding traditionally done enclosing name inside codice_1 omitting parentheses leads make interpreting next letter entire variable name equivalent form uses curly braces rather parentheses i.e codice_2 style used bsds new_macro macro macro2 macros composed shell commands using command substitution operator denoted backticks codice_3 yyyymmdd date content definition stored lazy evaluation used meaning macros normally expanded expansions actually required used command lines rule extended example package package version date y. archive package version dist generic syntax overriding macros command line make macro= value macro= value ... target target ... makefiles access number predefined internal macros common target component1 component2 suffix rules targets names form codice_4 used launch actions based file extension command lines suffix rules posix specifies internal macro codice_5 refers first prerequisite codice_6 refers target example converts html file text shell redirection token codice_7 part command line whereas codice_5 macro referring html file .suffixes .txt .html .html.txt called command line example expands make -n file.txt lynx -dump file.html file.txt suffix rules prerequisites treated normal files unusual names suffix rules gnu make supports suffix rules compatibility old makefiles otherwise encourages usage pattern rules pattern rule looks like ordinary rule except target contains exactly one character target considered pattern matching file names match substring zero characters characters match prerequisites likewise use show names relate target name example suffix rule would look like following pattern rule .txt .html single-line comments started hash symbol directives makefiles include makefiles line continuation indicated backslash codice_9 character end line makefiles traditionally used compiling code *.c *.cc *.c etc also used providing commands automate common tasks one makefile called command line make without argument runs first target make help show available targets make dist make release archive current dir makefile package package version date y. release_dir .. release_file package version help list dist simple makefile default rule listed first compiles source file called helloworld.c using system c compiler also provides clean target remove generated files user desires start codice_6 codice_5 two so-called internal macros also known automatic variables stand target name implicit source respectively example codice_12 expands space delimited list prerequisites number internal macros cflags -g helloworld helloworld helloworld.o helloworld.o helloworld.c clean frc frc many systems come predefined make rules macros specify common tasks compilation based file suffix lets users omit actual often unportable instructions generate target source system makefile could modified follows helloworld helloworld helloworld.o clean frc .c.o frc .suffixes .c helloworld.o depends helloworld.c automatically handled make simple example one illustrated hardly matters real power suffix rules becomes evident number source files software project starts grow one write rule linking step declare object files prerequisites make implicitly determine make object files look changes source files simple suffix rules work well long source files depend files header files another route simplify build process use so-called pattern matching rules combined compiler-assisted dependency generation final example requiring gcc compiler gnu make generic makefile compiles c files folder corresponding object files links final executable compilation takes place dependencies gathered makefile-friendly format hidden file .depend included makefile portable programs ought avoid constructs used ifneq makefile requires gnu make endif program foo c_files wildcard *.c objs patsubst .c .o c_files cc cc cflags -wall -pedantic ldflags ldlibs -lm program program .depend objs depend .depend .depend cmd gcc -mm -mf depend var cat depend » .depend .depend -include .depend .o .c .c clean .phony clean depend
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Programming language topics
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iphone 5 iphone 5 smartphone designed marketed apple inc sixth generation iphone succeeding iphone 4s preceding iphone 5s iphone 5c formally unveiled part press event september 12 2012 released september 21 2012 iphone 5 first iphone announced september setting trend subsequent iphone releases first iphone completely developed guidance tim cook last iphone overseen steve jobs iphone 5 featured major design changes comparison predecessor included aluminum-based body thinner lighter previous models taller screen nearly aspect ratio apple a6 system-on-chip lte support lightning new compact dock connector replaced 30-pin design used previous iphone models second apple phone include new sony-made 8 mp camera first introduced iphone 4s apple began taking pre-orders september 14 2012 two million received within 24 hours initial demand iphone 5 exceeded supply available launch september 21 2012 described apple extraordinary pre-orders sold twenty times faster predecessors reception iphone 5 generally positive consumers reviewers noted hardware issues unintended purple hue photos taken phone coating prone chipping reception also mixed apple decision switch different dock connector design change affected iphone 5 compatibility accessories otherwise compatible previous iterations line iphone 5 officially discontinued apple september 10 2013 announcement successors iphone 5s iphone 5c iphone 5 second-shortest lifespan iphone ever produced twelve months production breaking apple standard practice selling existing iphone model reduced price upon release new model broken iphone x ten-months production november 2017 september 2018 replaced midrange entry-level device iphone 5c 5c internal hardware specifications almost identical 5 albeit less expensive polycarbonate exterior iphone 5 supports ios 6 7 8 9 10 iphone 5 second iphone support five major versions ios iphone 4s rumors began shortly announcement iphone 4s though detailed leaks emerge june 2012 july 30 2012 reports pinpointed dates iphone 5 would unveiled released along accurate predictions features september 4 2012 apple announced would hosting event yerba buena center arts san francisco september 12 2012 shadow numeral 5 featured invitations sent media suggesting next iphone would unveiled event unveiling apple announced iphone 5 also introduced new ipod nano ipod touch models also stated pre-orders would accepted starting september 14 2012 two million pre-orders received within 24 hours initial demand new phone exceeded record set predecessor iphone 4s selling 5 million units first three days november 30 2012 apple added unlocked version iphone 5 online us store 16 gb model starting us 649 iphone 5 officially discontinued apple september 10 2013 announcement successors iphone 5s iphone 5c 5c shared almost internal hardware iphone 5 5c used lower-cost poly-carbonate plastic case place original 5 aluminum form introduction 5c deviated apple previous market strategy previous iphone model would remain production sold lower price point new model april 28 2014 apple initiated warranty recall program replace failing power buttons iphone 5 models manufactured prior march 2013 cost august 23 2014 apple announced program replace batteries iphone 5 models may suddenly experience shorter battery life need charged frequently sold september 2012 january 2013 following release iphone 5 samsung announced filing lawsuit apple infringing eight patents case scheduled begin 2014 statement samsung said little choice take steps necessary protect innovations intellectual property rights litigation two involving patent infringement ongoing fought several court cases around world components labor required construct basic iphone 5 estimated cost us 207 us 19 cost components corresponding iphone 4s model lte module iphone 5 alone costs 34 10 cellular module iphone 4s similarly screens used iphone 5 cost 44 7 screen predecessor mashable noted profit margin selling device huge iphone 5 retails us 649 announcement device lack supply evident due shortage components screen reports emerged stating sharp unable ship screen debut iphone 5 manufacturers reported difficult keep demand result number pre-orders rose due uncertainty stock retail stores delivery dates pre-orders postponed dates initial release date device china labor watch new york state–based ngo reported three four thousand foxconn workers work iphone 5 production plant zhengzhou stopped working october 5 2012 strikes occurred apple implemented stricter quality standard products includes 0.02 mm restriction indentations inflicted production imposed demands related scratches frames back covers strikes also attributed employer forcing employees work public holiday report stated training inadequate quality demands expected led employees producing products meet standards strike conflicts quality control inspectors employees resulted brawls china labor watch also claimed concerns raised inspectors addressed factory management foxconn spokesmen admitted micromanagement problem exists also said 300 400 workers absent conflicts influence production processes november 2012 foxconn chairman terry gou reported delay production due undisclosed difficulties assembly features ios apple mobile operating system user interface ios based concept direct manipulation using multi-touch gestures interface control elements consist sliders switches buttons interaction os includes gestures swipe tap pinch reverse pinch specific definitions within context ios operating system multi-touch interface internal accelerometers used applications respond shaking device one common result undo command rotating vertically one common result switching portrait landscape mode iphone 5 shipped ios 6 released september 19 2012 many features work specifically included ios 6.0 operating system worked certain territories release apple said rolling program take longer implement across regions phone act hotspot sharing internet connection wifi bluetooth usb also accesses app store online application distribution platform ios developed maintained apple service allows users browse download applications itunes store developed xcode ios sdk published apple play music movies television shows ebooks audiobooks podcasts sort media library songs artists albums videos playlists genres composers podcasts audiobooks compilations options always presented alphabetically except playlists retain order itunes users rotate device horizontally landscape mode access cover flow like itunes feature shows different album covers scroll-through photo library scrolling achieved swiping finger across screen alternatively headset controls used pause play skip repeat tracks iphone 5 volume changed included apple earphones voice control feature used identify track play songs playlist specific artist create genius playlist like iphone 4s iphone 5 siri allows user operate iphone spoken commands software improved ios 6 include ability make restaurant reservations launch apps dictate facebook twitter updates retrieve movie reviews detailed sports statistics texting aided voice assistant converts speech text addition regular texting messaging supports imessage specialized instant messaging program service allows unlimited texting apple devices running ios 5 later supports inclusion content images sound text messages integration device voice-controlled software assistant read acknowledgements sent messages input device comes keyboard displayed multi-touch screen voice-to text speaking microphone entered text supported predictive suggestion software multi-language spell-checker recognises many regional accents different languages ios 6 features several new and/or updated apps includes apple maps passbook apple built-in maps app replaced former maps app powered google maps universally derided lacked many features present competing maps apps uses apple new vector-based engine eliminates lag making smoother zooming new maps turn-by-turn navigation spoken directions 3d views major cities real-time traffic ios 6 able retrieve documents boarding passes admission tickets coupons loyalty cards new passbook app ios device passbook scanned reader process mobile payment locations compatible hardware app context-aware features notifications relevant coupons immediate vicinity given store facebook comes integrated apple native apps ios 6 facebook features directly accessed within native apps calendar sync facebook events use facebook like button within apple app store new privacy settings available user addition location services following added ios 6 photos already partially restricted ios 5 contacts address book calendars reminders bluetooth sharing twitter facebook sina weibo ios 6 also comes limit ad tracking user control general settings menu allow users option prevent targeted advertising apple advertising identifier replaces company existing unique device identification udid standard advertising networks yet using apple advertising identifier device identifier standard would affected although apple require standard future apple emphasized improved build quality iphone 5 press event frame used previous versions redesigned use aluminum composite frame used stainless steel instead aluminium due steve jobs preference metal thought looks beautiful wears 18 thinner 20 lighter 12 less overall volume predecessor iphone 4s phone aluminum body thick september 2012 conference apple claimed thinnest smartphone world 7.6 mm though claim disputed chinese oppo finder thinner smartphones could considered thinner depending upon thickness measured oppo finder measured thinnest point thickest point making overall thinner iphone uses system chip soc called apple a6 soc comprises 1.3 ghz dual-core processor 1gb ram tri-core powervr sgx543mp4 running 266 mhz. ref name= geekbench test 28/9 /ref operating memory lpddr2-1066 edram doubled 512 mb 1 gb storage capacities available fixed 16 32 64 gb 4s plug-in memory cards supported two color options black black glass slate-colored metal trim white white ceramic silver-colored metal trim color options though differently implemented predecessor 4s iphone 5 retains 8 megapixel back camera iphone 4s improved low-light performance 40 faster photo capture predecessors purple hue strong source light present photograph front camera accessible facetime camera app lower resolution 1.2 megapixels rechargeable lithium-ion battery charge capacity 1440mah built replaced user rated ≤225 hours standby time ≤8 hours talk time three separate models phone available one supporting cdma two gsm versions knock-on effects version device actually work countries/regions phone takes nano-sim smaller micro-sim hardware benchmarking conducted using geekbench glbenchmark validates several claims apple included website mentioned unveiling device include two times faster two times graphics performance geekbench overall hardware assessment iphone 5 received score approximately 2.5 times higher iphone 4s benchmark conducted using glbenchmark iphone 5 returned score 2 times better iphone 4s result however inconsistent 3d graphics benchmark assessment using passmark returned score approximately 1.45 times better iphone 4s battery life assessments conducted anandtech concluded battery life shorter iphone 5 predecessor performing certain tasks however performing tasks iphone 5 battery outlasts iphone 4s retina display 1,136 × 640 pixels aspect ratio almost exactly 16:9 minus one extra row horizontal pixels diagonal 4 display size 6.7 square inches compared 5.7 iphone 4 4s pixel density remains 4s model 326 pixels per inch screen icons iphone 5 arranged matrix six rows four icons increased screen size allows sixth row icons added five rows present iphone 4 in-cell touch sensor technology sharp slims screen allows thinner phone screen color saturation 44 greater predecessor three microphones placed front side back noise cancellation video calls april 28 2014 apple initiated warranty recall program replace failing power buttons iphone 5 models manufactured prior march 2013 cost august 23 2014 apple announced program replace batteries iphone 5 models may suddenly experience shorter battery life need charged frequently sold september 2012 january 2013 well ipod touch 5th generation ipod nano 7th generation ipad 4th generation ipad mini feature new dock connector named lightning replaces 30-pin apple dock connector introduced 2003 apple ipod 3rd generation apple lightning connector eight pins signaling digital new connector smaller previous one helping slimmer predecessors apple lightning cables duplicate pins two sides plug inserted either way round various accessories available convert apple lightning connector older 30-pin apple dock connector usb although old accessories work signals available particular video output ipod feature bmw automobiles earphones known apple earpods included iphone 5 devices announced apple media event september 12 2012 superseded earphones included previous generation iphones ipods according technology commentators redesign earphones aimed improve sound quality allowing air travel freely apple states redesign earphones allows rival high-end headphones cost hundreds dollars reviews gizmodo techradar reported although redesigned earphones sounded better predecessor reviewers felt quality sound produced poor verizon sprint offer lte access us uk ee three able offer lte access march 26 2013 t-mobile announced would begin carrying iphone 5 making first iphone available four nationwide carriers united states t-mobile version iphone features modified version a1428 iphone 5 model enabling advanced wireless services aws support carriers canada selling lte networks including rogers wireless fido solutions bell mobility virgin mobile canada telus mobility koodo mobile 42 officially recognized bands exist lte however rollouts coalescing around more-popular bands based historically made available specific regions europe bands available lte include 2.6 ghz 3g-expansion band 800 mhz cleared analogue tv 1,800 mhz appearing places including uk germany carrier network supported t-mobile 1,800 mhz band allocated lte countries europe including denmark norway sweden others—will able offer lte connectivity via iphone 5 customers current lte networks already deployed lte 2.6 ghz band iphone 5 support november 2012 representative swisscom reported iphone 5 supports lte networks tested certified apple unlike iphone 4s world phone produced apple three versions iphone 5 differ frequency used three work 2g gsm/gprs 3g umts/edge networks 800 1900 mhz bands used americas 900 1800 mhz bands used elsewhere cdma a1429 model works cdma networks sprint verizon another version supports lte 1700/2100 mhz aws band 700 mhz band recovered conversion digital television us channels 52 56 currently network supports band gsm a1429 supports several lte bands available countries lte bands 1 3 5 received mainly positive reviews commentators reviewers tim stevens engadget praised high resolution screen surpassing considered one best phone screens available market stevens critical new connector incompatible devices cables use superseded 30-pin connector although la times reported change necessary make device smaller predecessor engadget agreed apple fulfilled promises stated website better battery performance two times graphics performance two times faster david pogue new york times considered 4-inch retina display nice life-changing change praised lightning connector size sturdiness reversibility noting lack support older accessories remarking apple long history killing technologies inconveniently expensively public come love technology columnist ed baig usa today impressed apple met public lofty expectations iphone 5 competitive market repair-ability review ifixit found iphone 5 easier disassemble repair predecessor wired reported iphone 5 design carried iphone 5s iphone se regarded long golden child apple phone design benchmark phones general succeeding iphone 6/6s design less critically acclaimed felt little bit wrong though holding slick 650 bar soap wired described iphone 5 elegance rooted way aluminum glass work together felt streamlined yet substantial different iphone 6 feels substantial size alone plus unlike ubiquitous rounded corners 6 iphone 5 ’ really look like anything else market time however iphone 5 design suited scaling contrast iphone 6/6s could better accommodate growing consumer trend towards larger screen sizes indeed spawned 6/6s plus phablet models reviewers commentators critical new maps app replaced google maps ios 6 reported contain errors misplacement landmark tags directing users incorrect locations poor satellite images nine days maps release apple issued statement apologizing frustration caused customers recommending try alternate mapping services gizmodo editor diaz discussed correspondence apple reader purple flare pictures taken iphone 5 camera apple response issue normal advised customer aim camera away bright light sources taking photos tests conducted techcrunch indicate problem existed iphone 4s distinct pronounced iphone 5 consumer reports found purple haze effect occurred several manufacturers phones including samsung galaxy iii motorola droid razr maxx less pronounced iphone 4s report concluded digital cameras general including higher-end slrs suffer lens flare purple-tinted effect uncommon anecdotal claims iphone 5 coating chipping exposing bright aluminium underneath apple executive response email correspondence affected customer summarized normal aluminum scratch term scuffgate reference antennagate affected iphone 4 applied various sources cnet yahoo news things digital describe scuffing issue users reported internet white model leaked light behind screen though issue unique iphone 5 also affected apple devices techcrunch reported sold twenty times faster 4 4s models apple said blown away customer response phil schiller apple vice-president worldwide marketing said two million orders received first 24 hours said fastest-selling iphone company ever offered selling five million units launch weekend exceeding supply available release sale iphone 5 also slowed growth android according market share reports released kantar worldpanel comtech first 16 days phone initial release comprised 20 phones sold period j.p. morgan chief economist michael feroli said sales could boost annualized us gdp growth 3.2 billion 12.8 billion annual rate shortly announcement iphone 5 preceding launch apple stock price rose record 705.07 within three months fell 507.48 according analysis eric savitz apple stock decline resulting losses result issue new maps application disappointed investors points initial hardware sales five million compared projections twice primary cause since release iphone 5 discounts previous generation iphones enabled apple maintain market lead united states japan iphone continued lag behind combined total android phones global market
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Operating systems
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annapurna labs annapurna labs israel-based microelectronics company acquired amazon.com amazon web services division reputedly us 350–370m january 2015 annapurna labs owned avigdor willenz investors including british-based holding companies venture capital firm walden international board members include lip-bu tan ceo walden international cadence design systems features features al73400 announced november 2018 amazon aws invent 2018 features
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Computer architecture
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macrium reflect macrium reflect backup utility microsoft windows developed paramount software uk ltd 2006 creates disk images file backup archives using microsoft volume shadow copy service ensure 'point time data accuracy macrium reflect backup whole partitions individual files folders single compressed mountable archive file used restore exact images partitions hard disk disaster recovery new hard disk data migration received numerous favorable reviews often recommended used example program cloning backup tutorials macrium reflect create full incremental differential backup images selectively back individual files folders data compressed encrypted real time using lz-based compression aes encryption algorithms images mounted drive letter windows explorer restored using custom macrium reflect rescue cd event partial complete system loss image used restore entire disk one partitions individual files folders macrium reflect clone one disk onto another restore image new hardware using pre-created macrium reflect rescue cd critical drivers required new system inserted image taken old system making compatible new hardware central management console available enables scheduling restore monitoring multiple networked computers running macrium reflect using web browser user interface unsupported free edition available home commercial use lacks features full versions incremental backup though includes differential backup still features found expensive commercial products
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Computer security
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ettore perazzoli ettore perazzoli june 15 1974 december 10 2003 italian free software developer born milan italy studied engineering politecnico di milano university wrote port x64 commodore 64 emulator unix dos thus turning cross-platform emulator renamed vice maintainer vice many years started microsoft windows port popular version vice started contributing gnome linux desktop environment helped writing gtkhtml nautilus evolution close friend nat friedman miguel de icaza invited work company founded ximian accepted 2001 moved boston united states ximian headquartered ximian led effort create evolution remained project manager died started writing application managing digital photo albums c personal use november 8 2003 published gnome concurrent versions system cvs server name f-spot december 12 2003 gnomedesktop.org website announced death
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Operating systems
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avg antivirus avg antivirus previously known avg abbreviation anti-virus guard family antivirus software developed avg technologies subsidiary avast available windows macos android brand avg comes grisoft first product anti-virus guard launched 1992 czech republic 1997 first avg licenses sold germany uk avg introduced u.s. 1998 avg free edition helped raise awareness avg product line 2006 avg security package grew include anti-spyware avg technologies acquired ewido networks anti-spyware group avg technologies acquired exploit prevention labs xpl december 2007 incorporated company linkscanner safe search surf technology avg 8.0 security product range released march 2008 january 2009 avg technologies acquired sana security developer identity theft prevention software software incorporated avg security product range march 2009 according avg technologies company 200 million active users worldwide including 100 million use products services mobile devices 7 july 2016 avast announced agreement acquire avg 1.3 billion avg provides avg antivirus free windows avg antivirus mac macos avg antivirus android android devices freemium products free download install update use technical support premium plan must purchased avg stopped providing new features windows xp windows vista january 2019 new versions require windows 7 later virus definitions still provided previous versions avg features common functions available modern antivirus internet security programs including periodic scans scans sent received emails including adding footers emails indicating ability repair virus-infected files quarantine area virus vault infected files held patent pending linkscanner technology acquired exploit prevention labs built avg products provides real-time updated protection exploits drive-by downloads linkscanner includes search-shield – safe search component places safety ratings next link google yahoo msn search results plus active surf-shield – safe surf component scans contents web site real-time ensure safe opened concerns regarding web analytics made linkscanner controversial component see linkscanner concerns avg 8.0 first released linkscanner safe search feature shown cause increase traffic web sites appear high search engine results pages since linkscanner disguises scans coming internet explorer 6 browser prescans site listed search results web site usage logs showed incorrect overinflated site visitor statistics prescanning every link search results also caused web sites transfer data usual resulting higher bandwidth usage web site operators slow performance users avg initially said site administrators would able filter linkscanner traffic site statistics leaving problem excess bandwidth usage still solved pay-per-click advertising affected increase traffic avg online shield feature designed check files ensure safe avg online shield also ensures safety exchanging files via instant messengers voip clients response complaints avg announced 9 july 2008 search-shield longer scan search result online new exploits causing spikes webmasters addressed us releasing new build date applies local blacklist prefetches scans links clicked user 2014 numerous reports dating back 2012 avg safeguard toolbar installs without consent user side effect installing applications toolbar program appears cause significant ram issues considered intrusive potentially unwanted program pup installed avg toolbar virtually impossible remove toolbar uninstaller function instead re-installing add-on manually removed consequently many discussions blog posts described complex procedures removal avg toolbar mixed results september 2015 avg announced would start tracking users profit analyzing data sale advertising industry measure received criticism consumers press security industry many users intended use software order protect spyware would expect functions spyware hidden security software december 2015 avg web tuneup google chrome extension automatically installed avg antivirus revealed contain multiple critical security vulnerabilities notably chrome users browsing history could exposed website cookies site user visited could read attacker trivial cross-site scripting xss issues could allow website execute arbitrary code another domain xss vulnerability allowed user mail mail.google.com read website financial information read user online banking site avg team fixed allowing mysearch.avg.com webtuneup.avg.com execute scripts despite remediation attackers could leverage attacks xss vulnerability found avg sites april 2016 web tuneup still available download avg website avg antivirus free 2012 selected pc magazine editors choice free antivirus category avg antivirus free 2015 received editor choice badge softchamp
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Computer security
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purple penelope purple penelope demonstration secure system created defence research agency dra uk aim show security functionality windows nt could extended support users handling classified information purple penelope implemented domain based security model developed uk ministry defence dra take advantage using commercial shelf cots software implement secure systems within security domain access controls designed stop users accessing material without need-to-know prevent making mistakes handling classified data controls sharing information security domains stringent defend attacks hold users account actions model calls discretionary security labelling role based access controls within domain user-sanctioned release information domain coupled application oriented accounting audit purple penelope extended windows nt microsoft office application suite main features system discretionary labelling trusted path authorising security critical actions discretionary labelling mechanism added security labels files application windows clipboard user desktop display augmented stripe across top screen showed security label application window focus security label clipboard data copied clipboard clipboard label set source application window data copied clipboard destination application window label floated label new data user free change label window clipboard time user also access shared file store files shared file store labelled opened application application window label set file shared file store could written directly application user able copy files shared file store required confirm action using trusted path interface inaccessible applications software created purple penelope project licensed argus systems developed product called deep purple software also laid foundation qinetiq sybard suite product work cross-domain guard led production dera swipsy firewall toolkit purple derived colour associated joint operations uk mod time penelope name wife odysseus tricked suitors weaving burial shroud day unpicking night slow progress thought reflect state secure system development time
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Computer security
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gradius video game arcade version gradius released internationally outside japan title nemesis although subsequent home releases original title home versions released various platforms nes msx home computer pc engine player controls trans-dimensional spaceship vic viper must battle waves enemies various environments game became synonymous phrase destroy core standard boss battles gradius series involved combat giant craft center would situated one several blue colored spheres bosses would designed way would straight passage exterior giant craft leads directly one cores player must fire shots passage avoiding attack patterns weapon emplacements body boss however small destructible walls situated passage impeding bullet shots damaging core must whittled away repeated well-placed shots way tiny walls represent boss shielding gauge core finally vulnerable attack bosses ability regenerate walls core sustained enough hits usually changes color blue red indicating critical condition destruction imminent upon destruction core piece boss may put commission seeing longer powered core cores destroyed entire boss defeated explodes satisfyingly note cores present organic bosses gradius bosses weak spots places mouth head eye gameplay begins vic viper relatively slow weak gun level capability generally insufficient engaging enemies vic viper gain greater capabilities collecting using power-up items arcade games utilize distinct power up-items correspond specific effect player character gradius single power-up item effect power-up item advance currently selected item power-up menu appears bottom screen desired power-up highlighted player obtain pressing power-up button returning menu initial state power-up highlighted development gradius began series creator hiroyasu machiguchi given team work asked kind game wanted develop response shoot 'em intent surpassing namco xevious made horizontal shooting game wanted reuse material scramble much possible originally naming game scramble 2 development lasted year refining experimenting gameplay team originally tried twenty different movement patterns options used process elimination something work story hiroyasu team inspired science fiction movies popular sci-fi films time star wars anime adaptations lensman team saw lensman together influenced game story plasma laser impressed gradius features laser weapon moai included add mysterious element game like xevious nazca lines gradius first released japan konami bubble system arcade board allows operators change software used proprietary magnetic-based media called bubble software game distributed standard printed circuit board north america europe title nemesis north american version nemesis features considerably increased difficulty compared japanese european version balance game spawns fleet orange enemies player loses life order provide many power-up capsules possible order recover many upgrades possible title screen also updated showing in-game reproduction promotional artwork behind logo first home conversion gradius released nintendo famicom console april 25 1986 japan due hardware limitations famicom many level designs simplified moai stage example lacks vertical scrolling present arcade game maximum amount options player upgrade reduced four two version added cheat code entered game paused grants player ship almost power-ups code would appear many later konami nes consoles contra life force becoming known konami code nes version gradius released north america december 1986 first nes game released konami region unlike original arcade game title kept unchanged regions nes version produced arcades nintendo vs. system board title vs. gradius well playchoice 10 cabinet msx version gradius released july 25 1986 japan months famicom version also released europe nemesis title version underwent changes similar famicom version adds slew exclusive content make downgrade new stage bone planet added inverted volcano stage antennoid stage featuring exclusive enemy types also four hidden warp zones ability play titular ship twinbee msx version game played alongside nemesis pc engine version gradius released november 15 1991 exclusively japan released 2-megabit hucard relatively omissions compared nes msx versions added desert planet stage similar bone planet stage msx version lower resolution pc engine compared original arcade hardware pc engine features slight vertical-scrolling addition msx gradius also ported microcomputers shortly release zx spectrum amstrad cpc commodore 64 europe nemesis final challenge well nec pc-8801 sharp x1 japan port x68000 computer also included early models computer original gradius also included collection gradius deluxe pack playstation sega saturn gradius collection playstation portable arcade version digitally released playstation 4 part arcade archives series option play four regional variants game game went number 2 uk sales charts behind feud western cover art nes version claimed sold one million copies japan gamespot stated gradius one toughest side-scrolling shooter games available nes second contra ign given game rating 7 10 re-release wii virtual console hailed one greatest classic side-scrolling shooter games gradius spawned several sequels first 1986 salamander series continued seventh generation gradius rebirth also re-released windows store december 20 2013 gamenow may 2014 playstation 4 arcade archives january 25 japan nes port re-released nintendo switch online september 19 2018 worldwide update release november 14 2018 worldwide
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Computer architecture
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package macos apple macos operating system package file system directory normally displayed user finder single file directory may top-level directory tree objects stored files may archives files objects various purposes installer packages backup archives package common file system abstraction used apple operating systems macos ios directory may contain hierarchy files objects represent preserved organized state package displayed users like single file finder application avoid changed user however content packages may accessed special keyboard mouse combination events purpose control-click right-click menu displays directive show package contents documents may represented packages uniform type identifier uti package com.apple.package package standardized structure storing executable code associated resources called bundle
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Operating systems
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boundschecker boundschecker memory checking api call validation tool used c++ software development microsoft visual c++ created numega early 1990s numega purchased compuware 1997 boundschecker became part larger tool suite devpartner studio micro focus purchased product line compuware 2009 comparable tools include purify insure++ valgrind boundschecker may run two distinct modes activecheck work application finalcheck makes use instrumentation added application built activecheck performs less intrusive analysis monitors calls application c runtime library windows api calls com objects monitoring memory allocations releases detect memory leaks overruns monitoring api com calls enables activecheck check parameters returns exceptions report exceptions occur thread deadlocks also detected monitoring synchronization objects calls giving actual potential deadlock detection finalcheck requires instrumented build gives much deeper intrusive analysis provides detection features activecheck plus ability detect buffer overflows read write uninitialized memory accesses monitors every scope change tracks pointers referencing memory objects api calls monitored input parameters verified function calls actually performed warning possible problems api return codes also monitored error codes logged validation limited apis known boundschecker currently several thousand number memory tracking enabled api call validation make use information gathered precise validation memory pointers memory tracking api validation enabled becomes possible detect many kinds array buffer overrun conditions compiler instrumentation enhances ability feature product originally named api com method .net interop function calls logged detail noting call parameter values resulting return values feature limited value non-trivial applications often result session log quickly becoming large report generated analyzing .net interop garbage collection finalizer activity life process test certain kinds deadly embraces lockups detected current version 11.4.2898 boundschecker supports 32-bit 64-bit native applications windows xp windows 10 2019 spring update ms-dos 16-bit windows windows 2000 applications longer supported part devpartner studio product integrates visual studio 2005 sp1 2008 sp1 2010 sp1 2012 update 4 2013 update 4 2015 update 3 2017 update 15.9.11 2019 update 16.0.3 may 2019 deadlock analysis feature yet supported x64 applications
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Operating systems
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host protected area host protected area hpa area hard drive solid-state drive normally visible operating system first introduced ata-4 standard cxv t13 2001 ide controller registers contain data queried using ata commands data returned gives information drive attached controller three ata commands involved creating using host protected area commands operating systems use identify device command find addressable space hard drive identify device command queries particular register ide controller establish size drive register however changed using set max address ata command value register set less actual hard drive size effectively host protected area created protected os work value register returned identify device command thus normally unable address parts drive lie within hpa hpa useful software firmware e.g bios able use software firmware able use hpa referred 'hpa aware ata command entities use called read native max address command accesses register contains true size hard drive use area controlling hpa-aware program changes value register read identify device found register read read native max address operations complete register read identify device returned original fake value identification hpa hard drive achieved number tools methods note hpa feature hidden dco commands documentation states hpa use frozen next power-down hard disk password protected windows program atatool detect hpa instance see first disk hpa use command using linux various ways detect existence hpa recent versions linux print message system booting hpa detected example program hdparm versions 8.0 detect hpa drive sdx invoked parameters versions hdparm 8 one compare number sectors output 'hdparm -i number sectors reported hard drive model published statistics windows program atatool used create hpa instance create 10gb hpa linux program hdparm version 8.0 create hpa invoked parameters sdx target drive number non-hpa visible sectors
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Computer security
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cp/m cp/m originally standing control program/monitor later control program microcomputers mass-market operating system created 1974 intel 8080/85-based microcomputers gary kildall digital research inc initially confined single-tasking 8-bit processors 64 kilobytes memory later versions cp/m added multi-user variations migrated 16-bit processors combination cp/m s-100 bus computers loosely patterned mits altair early standard microcomputer industry computer platform widely used business late 1970s mid-1980s cp/m increased market size hardware software greatly reducing amount programming required install application new manufacturer computer important driver software innovation advent comparatively low-cost microcomputers running cp/m independent programmers hackers bought shared creations user groups cp/m displaced dos soon 1981 introduction ibm pc minimal 8-bit cp/m system would contain following components hardware system cp/m sold digital research would support intel 8080 development system manufacturers cp/m-compatible systems customized portions operating system combination installed memory disk drives console devices cp/m would also run systems based zilog z80 processor since z80 compatible 8080 code digital research distributed core cp/m bdos ccp core transient commands use z80-specific instructions many z80-based systems used z80 code system-specific bios many applications dedicated z80-based cp/m machines machines bootstrap minimal bootloader rom combined means minimal bank switching means injecting code bus since 8080 needs see boot code address 0 start-up cp/m needs ram others bootstrap entered memory using front-panel controls time system started cp/m used 7-bit ascii set 128 characters made possible 8-bit byte standardized example one kaypro used greek characters osborne machines used 8th bit set indicate underlined character wordstar used 8th bit end-of-word marker international cp/m systems commonly used iso 646 norm localized character sets replacing certain ascii characters localized characters rather adding beyond 7-bit boundary 8-bit versions running cp/m operating system loaded memory three components bios bdos memory-resident ccp memory-resident unless overwritten application case automatically reloaded application finished running number transient commands standard utilities also provided transient commands resided files extension .com disk bios directly controlled hardware components cpu main memory contained functions character input output reading writing disk sectors bdos implemented cp/m file system input/output abstractions redirection top bios ccp took user commands either executed directly internal commands dir show directory era delete file loaded started executable file given name transient commands pip.com copy files stat.com show various file system information third-party applications cp/m also essentially transient commands bdos ccp standard transient commands ideally installations particular revision cp/m bios portion always adapted particular hardware adding memory computer example meant cp/m system reinstalled updated bios capable addressing additional memory utility provided patch supplied bios bdos ccp allow run higher memory installed operating system bios bdos ccp stored reserved areas beginning disk would used boot system start-up bootloader usually contained rom firmware chip would load operating system disk drive codice_1 modern standards cp/m primitive owing extreme constraints program size version 1.0 provision detecting changed disk user changed disks without manually rereading disk directory system would write new disk using old disk directory information ruining data stored disk version 1.1 1.2 onwards changing disk trying write directory read would cause fatal error signalled avoided overwriting disk required reboot loss data stored disk majority complexity cp/m isolated bdos lesser extent ccp transient commands meant porting limited number simple routines bios particular hardware platform entire os would work significantly reduced development time needed support new machines one main reasons cp/m widespread use today sort abstraction common oss hardware abstraction layer time cp/m birth oss typically intended run one machine platform multilayer designs considered unnecessary console command processor ccp accepted input keyboard conveyed results terminal cp/m would work either printing terminal video terminal cp/m commands typed command line console would often display codice_2 prompt indicate current default disk drive used video terminal would usually followed blinking cursor supplied terminal ccp would await input user ccp internal command form drive letter followed colon could used select default drive example typing codice_3 pressing enter command prompt would change default drive b command prompt would become codice_4 indicate change cp/m command-line interface patterned operating systems digital equipment rt-11 pdp-11 os/8 pdp-8 commands took form keyword followed list parameters separated spaces special characters similar unix shell builtin internal command recognized carried ccp otherwise would attempt find executable file currently logged disk drive later versions user area load pass additional parameters command line referred transient programs completion cp/m would reload part ccp overwritten application programs — allowed transient programs larger memory space commands could sometimes obscure instance command duplicate files named codice_5 peripheral-interchange-program name old dec utility used purpose format parameters given program standardized single option character differentiated options file names different programs could use different characters following list built-in commands supported cp/m console command processor transient commands cp/m include cp/m plus cp/m version 3 includes following built-in commands basic disk operating system bdos provided access operations opening file output console printing application programs would load processor registers function code operation addresses parameters memory buffers call fixed address memory since address independent amount memory system application programs would run way type configuration hardware basic input output system bios provided lowest level functions required operating system included reading writing single characters system console reading writing sector data disk bdos handled buffering data diskette cp/m 3.0 assumed disk sector size fixed 128 bytes used single-density 8-inch floppy disks since 5.25-inch disk formats used larger sectors blocking deblocking management disk buffer area handled model-specific code bios customization required hardware choices constrained compatibility one popular standard example manufacturers used separate computer terminal others designed built-in integrated video display system serial ports printers modems could use different types uart chips port addresses fixed machines used memory-mapped i/o instead 8080 i/o address space variations hardware concealed modules system use bios used standard entry points services required run cp/m character i/o accessing disk block since support serial communication modem rudimentary bios may absent altogether common practice cp/m programs used modems user-installed overlay containing code required access particular machine serial port file names specified string eight characters followed period followed file name extension three characters 8.3 filename format extension usually identified type file example codice_6 indicated executable program file codice_7 indicated file containing ascii text disk drive identified drive letter example drive codice_8 drive codice_9 refer file specific drive drive letter prefixed file name separated colon e.g codice_10 drive letter prefixed access files current default drive 8.3 filename format drive letter colon combination survived ms-dos drive letter colon convention survived microsoft windows still used today addition file extensions example codice_11 codice_12 compiled file codice_13 executable file still used identify file types many operating systems file size specified number 128 byte records directly corresponding disk sectors 8-inch drives occupied file disk generally supported way specifying byte-exact file sizes current size file maintained file file control block fcb operating system since many application programs text editors prefer deal files sequences characters rather sequences records convention text files terminated control-z character ascii sub hexadecimal 1a determining end text file therefore involved examining last record file locate terminating control-z also meant inserting control-z character middle file usually effect truncating text contents file advent larger removable fixed disk drives disk de-blocking formulas employed resulted disk blocks per logical file allocation block allowed larger file sizes also meant smallest file could allocated increased size 1 kb single-density drives 2 kb double-density drives 32 kb file containing single byte made inefficient use disk space disk contained large number small files file modification time stamps supported releases cp/m 2.2 optional feature mp/m cp/m 3.0 cp/m 2.2 subdirectories file structure provided 16 numbered user areas organize files disk change user one simply type user x command prompt x number user wanted security non-existent believed necessary user area concept make single-user version cp/m somewhat compatible multi-user mp/m systems common patch cp/m derivative operating systems make one user area accessible user independent currently set user area user command allowed user area changed area 0 15 user 0 default one changed another user user 1 material saved disk user would available user 1 user 2 would able see access however files stored user 0 area accessible users location specified prefatory path since files user 0 visible someone logged user 0 user area feature arguably little utility small floppy disks useful organizing files machines hard drives intent feature ease use computer different tasks example secretary could data entry switching user areas another employee could use machine billing without files intermixing read/write memory address 0100 hexadecimal lowest address bdos transient program area tpa available cp/m application programs although z80 8080 processors could address 64 kilobytes memory amount available application programs could vary depending design particular computer computers used large parts address space things bios roms video display memory result systems tpa memory available others bank switching common technique allowed systems large tpa switching rom video memory space needed cp/m 3.0 allowed parts bdos bank-switched memory well cp/m came dynamic debugging tool nicknamed ddt insecticide i.e bug-killer allowed memory program modules examined manipulated allowed program executed one step time cp/m originally support equivalent terminate stay resident program dos programmers could write software could intercept certain operating system calls extend alter functionality using capability programmers developed sold auxiliary desk accessory programs smartkey keyboard utility assign string bytes key cp/m 3 however added support dynamically loadable resident system extensions rsx similar solutions like rsm also retrofitted cp/m 2.2 systems third-parties although cp/m provided hardware abstraction standardize interface disk i/o console i/o typically application programs still required installation make use features equipment printers terminals often controlled escape sequences altered different devices example escape sequence select bold face printer would differed among manufacturers sometimes among models within manufacturer range procedure defined operating system user would typically run installation program would either allow selection range devices else allow feature-by-feature editing escape sequences required access function repeated application program since central operating system service provided devices initializing codes model printer written application use program wordstar one printer say fast dot matrix printer slower presentation-quality daisy wheel printer separate version wordstar prepared one load wordstar version corresponded printer selected exiting reloading change printers gary kildall originally developed cp/m 1974 operating system run intel intellec-8 development system equipped shugart associates 8-inch floppy disk drive interfaced via custom floppy disk controller written kildall pl/m programming language microcomputers various aspects cp/m influenced tops-10 operating system decsystem-10 mainframe computer kildall used development environment cp/m originally stood control program/monitor name implies resident monitor—a primitive precursor operating system however conversion cp/m commercial product trademark registration documents filed november 1977 gave product name control program microcomputers cp/m name follows prevailing naming scheme time kildall pl/m language prime computer pl/p programming language prime suggesting ibm pl/i ibm cp/cms operating system kildall used working naval postgraduate school renaming cp/m part larger effort kildall wife/business partner convert kildall personal project cp/m intel-contracted pl/m compiler commercial enterprise kildalls intended establish digital research brand product lines synonymous microcomputer consumer mind similar ibm microsoft together later successfully accomplished making personal computer synonymous product offerings intergalactic digital research inc. later renamed via corporation change-of-name filing digital research inc. september 1981 digital research sold cp/m licenses infoworld stated actual market likely larger sublicenses many different companies produced cp/m-based computers many different markets magazine stated cp/m well way establishing small-computer operating system companies chose support cp/m large library software xerox 820 ran operating system literally thousands programs written would unwise take advantage xerox said xerox included howard w. sams cp/m manual compensation digital research documentation infoworld 1982 described atrocious 1984 columbia university used source code build kermit binaries dozen different cp/m systems plus generic version operating system described software bus allowing multiple programs interact different hardware standardized way programs written cp/m typically portable among different machines usually requiring specification escape sequences control screen printer portability made cp/m popular much software written cp/m operating systems ran one brand hardware one restriction portability certain programs used extended instruction set z80 processor would operate 8080 8085 processor another graphics routines especially games graphics programs generally machine-specific used direct hardware access speed bypassing os bios also common problem early dos machines bill gates claimed apple ii family z-80 softcard single most-popular cp/m hardware platform many different brands machines ran operating system notable examples altair 8800 imsai 8080 osborne 1 kaypro luggables msx computers best-selling cp/m-capable system time probably amstrad pcw uk cp/m also available research machines educational computers cp/m source code published educational resource bbc micro equipped z80 co-processor furthermore available amstrad cpc series commodore 128 trs-80 later models zx spectrum cp/m 3 also used niat custom handheld computer designed a.c. nielsen internal use 1 mb ssd memory wordstar one first widely used word processors dbase early popular database program microcomputers originally written cp/m two early outliners kamas knowledge mind amplification system cut-down successor out-think without programming facilities retooled 8080/v20 compatibility also written cp/m though later rewritten ms-dos turbo pascal ancestor borland delphi multiplan ancestor microsoft excel also debuted cp/m ms-dos versions became available visicalc first-ever spreadsheet program made available cp/m another company sorcim created supercalc spreadsheet cp/m would go become market leader de facto standard cp/m supercalc would go competitor spreadsheet market ms-dos world autocad cad application autodesk debuted cp/m host compilers interpreters popular programming languages time basic borland turbo pascal fortran available among several earliest microsoft products cp/m software often came installers adapted wide variety computers source code basic programs easily accessible forms copy protection ineffective operating system kaypro ii owner example would obtain software xerox 820 format copy run kaypro-format disks lack standardized graphics support limited video games various character text-based games ported telengard gorillas hamurabi lunar lander along early interactive fiction including zork series colossal cave adventure text adventure specialist infocom one publishers consistently release games cp/m format lifeboat associates started collecting distributing user-written free software one first xmodem allowed reliable file transfers via modem phone line another program native cp/m outline processor kamas ibm system/34 ibm 3740 single-density single-sided format cp/m standard 8-inch floppy disk format standard 5.25-inch cp/m disk format exists kaypro morrow designs osborne others using infoworld estimated september 1981 two dozen formats popular enough software creators consider reach broadest possible market jrt pascal example provided versions 5.25-inch disk north star osborne apple heath hard sector soft sector superbrain one 8-inch version ellis computing also offered software heath formats 16 5.25-inch formats including two different trs-80 cp/m modifications certain disk formats popular others software available xerox 820 format computers kaypro ii compatible single manufacturer however prevailed 5.25-inch era cp/m use disk formats often portable hardware manufacturers software manufacturer prepare separate version program brand hardware run manufacturers kaypro example even standardization across company different models situation disk format translation programs allowed machine read many different formats became popular reduced confusion programs like kermit allowed transfer data programs one machine another using serial ports cp/m machines various formats used depending characteristics particular systems degree choices designers cp/m supported options control size reserved directory areas disk mapping logical disk sectors seen cp/m programs physical sectors allocated disk many ways customize parameters every system set standardized way existed system load parameters disk formatted another system degree portability different cp/m machines depended type disk drive controller used since many different floppy types existed cp/m era 8-inch 5.25-inch format disks could hard soft sectored single double density single double sided 35 track 40 track 77 track 80 track sector layout size interleave could vary widely well although translation programs could allow user read disk types different machines also depended drive type controller 1982 soft sector single sided 40 track 5.25-inch disks become popular format distribute cp/m software used common consumer-level machines time apple ii trs-80 osborne 1 kaypro ii ibm pc translation program allowed user read disks machine similar format—for example kaypro ii could read trs-80 osborne ibm pc epson disks disk types 80 track hard sectored completely impossible read first half double sided disks like epson qx-10 could read cp/m accessed disk tracks sequentially track 0 first outermost track side 1 track 79 40 track disk last innermost track side 2 apple ii users could use anything apple gcr format obtain cp/m software apple format disks else transfer via serial link fragmented cp/m market requiring distributors either stock multiple formats disks invest multiformat duplication equipment compared standardized ibm pc disk formats contributing factor rapid obsolescence cp/m 1981 one last notable cp/m capable machines appear commodore 128 1985 z80 cp/m support addition native mode using 6502-derivative cpu using cp/m required either 1571 1581 disk drive could read soft sector 40 track mfm format disks first computer use 3.5-inch floppy drive sony smc-70 ran cp/m 2.2 commodore 128 bondwell-2 laptop micromint/ciarcia sb-180 msx trs-80 model 4 running montezuma cp/m 2.2 also supported use cp/m 3.5-inch floppy disks amstrad pcw ran cp/m using 3 inch floppy drives first later switched 3.5 inch drives although graphics-capable s-100 systems existed commercialization s-100 bus cp/m provide standardized graphics support 1982 gsx graphics system extension owing small memory available graphics never common feature associated 8-bit cp/m operating systems systems could display rudimentary ascii art charts diagrams text mode using custom character set computers kaypro line trs-80 model 4 video hardware supporting block graphics characters accessible assembler programmers basic programmers using chr command model 4 could display 640 240 pixel graphics optional high resolution board 1979 multi-user compatible derivative cp/m released mp/m allowed multiple users connect single computer using multiple terminals provide user screen keyboard later versions ran 16-bit processors last 8-bit version cp/m version 3 often called cp/m plus released 1983 incorporated bank switching memory management mp/m single-user single-task operating system compatible cp/m 2.2 applications cp/m 3 could therefore use 64 kb memory 8080 z80 processor system could configured support date stamping files operating system distribution software also included relocating assembler linker cp/m 3 available last generation 8-bit computers notably amstrad pcw amstrad cpc zx spectrum +3 commodore 128 msx machines radio shack trs-80 model 4 versions cp/m 16-bit cpus well first version 16-bit family cp/m-86 intel 8086 soon followed cp/m-68k motorola 68000 original version cp/m-68k 1982 written pascal/mt+68k ported c later point original 8-bit cp/m became known retronym cp/m-80 avoid confusion ca 1982/1983 also port zilog z8000 olivetti m20 written c named cp/m-8000 cp/m-86 expected standard operating system new ibm pcs dri ibm unable negotiate development licensing terms ibm turned microsoft instead microsoft delivered pc dos based 86-dos although cp/m-86 became option ibm pc dri threatened legal action never overtook microsoft system customers repelled significantly greater price ibm charged cp/m-86 pc dos digital equipment corporation dec put rainbow 100 compete ibm came cp/m-80 using z80 chip cp/m-86 ms-dos using 8088 microprocessor cp/m-86/80 using z80 8088 cpus ran concurrently benefit rainbow could continue run 8-bit cp/m software preserving user possibly sizable investment moved 16-bit world ms-dos cp/m-68k already running motorola exormacs systems initially used atari st computer atari decided go newer disk operating system called gemdos cp/m-68k also used sord m68 m68mx computers 16-bit versions cp/m required application programs re-compiled new cpus written assembly language translated using tools like digital research xlt86 program written gary kildall 1981 translated .asm source code intel 8080 processor .a86 source code intel 8086 using global data flow analysis 8080 register usage translator would also optimize output code size take care calling conventions cp/m-80 mp/m-80 programs could ported cp/m-86 mp/m-86 platforms automatically xlat86 written pl/i-80 available cp/m-80 platforms well dec vms vax 11/750 11/780 many expected cp/m would standard operating system 16-bit computers 1980 ibm approached digital research bill gates suggestion license forthcoming version cp/m new product ibm personal computer upon failure obtain signed non-disclosure agreement talks failed ibm instead contracted microsoft provide operating system resulting product ms-dos soon began outselling cp/m many basic concepts mechanisms early versions ms-dos resembled cp/m internals like file-handling data structures identical referred disk drives letter codice_1 codice_3 etc. ms-dos main innovation fat file system similarity made easier port popular cp/m software like wordstar dbase however cp/m concept separate user areas files disk never ported ms-dos since ms-dos access memory ibm pcs sold less 64 kb memory cp/m could run 16 kb necessary commands built command-line shell making ms-dos somewhat faster easier use floppy-based computers although one first peripherals ibm pc softcard-like expansion card let run 8-bit cp/m software cp/m rapidly lost market share microcomputing market moved ibm-compatible platform never regained former popularity byte magazine time one leading industry magazines microcomputers essentially ceased covering cp/m products within years introduction ibm pc example 1983 still advertisements s-100 boards articles cp/m software 1987 longer found magazine 1984 article infoworld stated efforts introduce cp/m home market largely unsuccessful cp/m software expensive home users 1986 stated kaypro stopped production 8-bit cp/m-based models concentrate sales ms-dos compatible systems long vendors ceased production new equipment software cp/m later versions cp/m-86 made significant strides performance usability made compatible ms-dos reflect compatibility name changed cp/m-86 became dos plus turn became dr-dos zcpr z80 command processor replacement introduced 2 february 1982 drop-in replacement standard digital research console command processor ccp initially written group computer hobbyists called ccp group frank wancho keith petersen archivist behind simtel time ron fowler charlie strom bob mathias richard conn. richard fact driving force group maintained contact email zcpr1 released disk put sig/m special interest group/microcomputers part amateur computer club new jersey zcpr2 released 14 february 1983 released set ten disks sig/m zcpr2 upgraded 2.3 also released 8080 code permitting use zcpr2 8080 8085 systems zcpr3 released bastille day 14 july 1984 set nine disks sig/m code zcpr3 could also compiled reduced features 8080 would run systems requisite z80 microprocessor january 1987 richard conn stopped developing zcpr echelon asked jay sage already privately enhanced zcpr 3.1 continue work thus zcpr 3.3 developed released zcpr 3.3 longer supported 8080 series microprocessors added features upgrade zcpr line features zcpr version 3 included zcpr3.3 also included full complement utilities considerably extended capabilities enthusiastically supported cp/m user base time zcpr alone insufficient slow demise cp/m number cp/m-80 derivatives existed former east-bloc various names including scp scp/m cp/a cp/kc cp/l cp/ksob cp/z microdos bcu880 zoaz os/m tos/m zsdos m/os cos-psa dos-psa csoc csos cz-cpm others also cp/m-86 derivatives named scp1700 cp/k k8918-os produced east-german veb robotron others number behaviors exhibited microsoft windows result backward compatibility ms-dos turn attempted backward compatibility cp/m drive letter 8.3 filename conventions ms-dos early windows versions originally adopted cp/m wildcard matching characters used windows based cp/m reserved filenames used redirect output printer prn console con drive names b used designate two floppy disk drives cp/m systems typically used hard drives appeared designated c survived ms-dos codice_16 command prompt control character ^z marking end text files also attributed cp/m 1997 1998 caldera released cp/m 2.2 binaries source code open source license also allowing redistribution modification collected digital research files related cp/m mp/m families tim olmstead unofficial cp/m web site since 1997 olmstead death 12 september 2001 distribution license refreshed expanded lineo meanwhile become owner digital research assets 19 october 2001 october 2014 mark 40th anniversary first presentation cp/m computer history museum released early source code versions cp/m number active vintage hobby retro-computer people groups small commercial businesses still developing supporting compute platforms use cp/m mostly 2.2 host operating system
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Operating systems
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third-generation programming language third-generation programming language 3gl generational way categorize high-level computer programming languages assembly languages categorized second-generation programming languages machine-dependent 3gls much machine independent programmer-friendly includes features like improved support aggregate data types expressing concepts way favors programmer computer third generation language improves second generation language computer take care non-essential details 3gls abstract previous generations languages thus considered higher level languages first second generation counterparts first introduced late 1950s fortran algol cobol examples early 3gls popular general-purpose languages today c c++ c java basic pascal also third-generation languages although languages subdivided categories based contemporary traits 3gls support structured programming many support object-oriented programming traits like often used describe language rather 3gl programming language c fortran pascal enables programmer write programs less independent particular type computer languages considered high-level closer human languages machine languages hence require compilation interpretation contrast machine languages considered low-level designed executed physical hardware without translation required main advantage high-level languages low-level languages easier read write maintain ultimately programs written high-level language must translated machine language compiler directly behaviour interpreter programs could run different machines machine-independent new abstract languages developed however concept high low level languages become rather relative many early high level languages considered relatively low level comparison languages python ruby common lisp features fourth-generation programming languages
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Programming language topics
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leading edge hardware products leading edge hardware products inc. computer manufacturer 1980s 1990s based canton massachusetts leading edge founded 1980 thomas shane michael shane outset pc peripherals company selling aftermarket products elephant memory systems brand floppy disk media elephant never forgets printer ribbons acting sole north american distributor/reseller printers japanese manufacturer c. itoh memorable popular low-end dot-matrix printer gorilla banana 1984 company sold computer aftermarket product line sales division dennison computer supplies division dennison manufacturing 1984 began use daewoo parts 1989 acquired daewoo part recovery chapter 11 bankruptcy shane declared costs legal dispute mitsubishi lead bankruptcy january 1990 daewoo hired al agbay veteran executive panasonic lead company chapter 11 bankruptcy three years followed agbay executive team repaid dealers approximately 16 million increased annual revenues 250 million contract dispute severed agbay daewoo relationship october 1995 daewoo sold company manuhold investment ag swiss electronics company leading edge sold 185,000 pc clones united states 1994 1995 sales fell 90,000 first half almost none second half 1997 company defunct first known computer produced leading edge model released 1982 1986 sold 1695 us monitor two floppy drives used intel 8088-2 processor running maximum 7.16 mhz 8 bit bus compared 6 mhz ibm pc-at 16 bit bus 'm stands mitsubishi parts provider began producing leading edge model june 1985 began use daewoo parts model described quality good price right consumer reports best buy ibm compatible using intel 8088 16 bit processor ibm pc two floppy disc drives 256k ram amber monitor machine sold 1495 us sold 125,000 first 13 months reduced price 1295 us ibm started supplying 20 meg hard drives standard newer pc-xt leading edge supplied 30 meg hard drive standard later released model d86 intel 8086 model d2 1988 65 mb hard drive 2495 us 10 mhz processor intel 80286 model d3 intel 80386 1993 leading edge marketed winpro series computers computers i486 intel 80486 processors low end model i486 sx25 processor—which lacked fpu i486 dx33 processor fpu computers 3.5 inch floppy 5.25 floppy 170mb hard drive 4mb ram could expanded 20mb needed windows 3.1 ms-dos 5.0 operating systems cost leading edge computer ranged 1299.99 2199.99 time 1994 leading edge marketed wintower 486 multimedia pc 66 mhz processor 8 mb ram 340 mb hard drive 2 floppies cd rom modem sound card monitor street price 2600 us one programs offered leading edge computers leading edge word processor described easy use created automatic backup copies loaded 256 k ram described large amount program memory floppy drives available storage introduced 1983 sold 1984 100 u.s. lewp called easy use word processor features bred newer systems great deal later automatically fixed transpositions run feature seen sophisticated contemporary word processing programs 1984 leading edge also released innovative database application called nutshell developed company called nashoba systems distributed leading edge nutshell earlier form program later released filemaker subsequently filemaker pro
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Computer architecture
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james martin author james martin 19 october 1933 – 24 june 2013 british information technology consultant author known work information technology engineering james martin born 19 october 1933 ashby-de-la-zouch england earned degree physics keble college oxford martin joined ibm 1959 since 1980s established several consultancy firms starting 1981 dixon doll tony carter established dmw doll martin worldwide london uk later renamed james martin associates jma partly bought texas instruments software 1991 later co-founded database design inc. ddi ann arbor michigan promulgate database design techniques develop tools help implement becoming market leader information technology engineering software ddi renamed knowledgeware eventually purchased fran tarkenton took public martin awarded honorary fellowship keble college oxford honorary doctor science degree university warwick july 2009 gave turing lecture 2008 according computerworld ’ 25th anniversary issue ranked fourth among 25 individuals influenced world computer science 1990s onwards martin lived private island agar ’ island bermuda died 24 june 2013 apparently swimming accident martin expert field systems design software development methodology information technology engineering computer-aided software engineering one first promote fourth-generation programming languages one main developers rapid application development methodology information technology engineering ite approach designing developing information systems somewhat chequered history follows two distinct threads said originated australia 1976 1980 appears first literature 1981 savant institute publication information engineering james martin clive finkelstein information technology engineering first provided data analysis database design techniques could used database administrators dbas systems analysts develop database designs systems based upon understanding operational processing needs organisations 1980s finkelstein thread evolved 1980 data processing dp -driven variant ie 1983 till 1986 ie evolved business-driven variant ie intended address rapidly changing business environment technical director charles m. richter 1983 1987 played significant role revamping ie methodology well designing ie software product user-data helped automate ie methodology opening way next generation information architecture martin thread information technology engineering strategy-driven outset 1983 focused possibility automating development process provision techniques business description could used populate data dictionary encyclopaedia could turn used source material code generation martin methodology provided foundation case computer-aided software engineering tool industry martin significant stakes least four case tool vendors—intech excelerator higher order software knowledgeware originally database design inc information engineering workbench james martin associates originally dmw headstrong original designers texas instruments ’ ca gen facility principal developers methodology end 1980s early 1990s martin thread incorporated rapid application development rad business process re-engineering bpr soon also entered object oriented field rapid application development rad term originally used describing software development process first developed successfully deployed mid-1970s d.dinadasa getahetta telephone co systems development center direction dan gielan following series remarkably successful implementations process gielan lectured extensively various forums methodology practice benefits process martin introduced approach 1991 martin ’ methodology involves iterative development construction prototypes recently term acronym come used broader generic sense encompasses variety techniques aimed speeding application development use web application frameworks types software frameworks rad approaches may entail compromises functionality performance exchange enabling faster development facilitating application maintenance 2004 martin donated £60m help establish james martin 21st century school 2010 renamed oxford martin school university oxford largest single donation university school aims formulate new concepts policies technologies make future better place 2009 martin pledged additional 50 million could matched donors condition met april 2010 martin wrote hundred books many best sellers information technology industry selection
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Databases
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imo number international maritime organization imo number unique reference ships registered ship owners management companies imo numbers introduced improve maritime safety security reduce maritime fraud consist three letters imo followed unique seven-digit numbers assigned international convention safety life sea solas 1987 imo adopted resolution a.600 15 aimed enhancement maritime safety pollution prevention prevention maritime fraud assigning ship permanent identification number imo number remains linked hull lifetime regardless changes names flags owners imo adopted existing unique 7-digit numbers applied ships lloyd register since 1969 modified 6-digit numbers introduced 1963 solas regulation xi/3 adopted 1994 came force 1 january 1996 made imo numbers mandatory applied cargo vessels least 300 gross tons gt passenger vessels least 100 gt solas convention cargo ships means ships passenger ships imo scheme however apply december 2002 diplomatic conference maritime security adopted number measures aimed enhancing security ships port facilities included modification solas regulation xi-1/3 require ships identification numbers permanently marked visible place either ship hull superstructure well internally ship certificates passenger ships also carry marking horizontal surface visible air may 2005 imo adopted new solas regulation xi-1/3-1 mandatory company registered owner identification number scheme entry force 1 january 2009 regulation provides every ship owner management company shall unique identification number amendments require numbers added relevant certificates documents international safety management code ism international ship port facility security code isps like imo ship identification number company identification number seven-digit number prefix imo example ship atlantic star imo 5304986 referred former ship manager pullmantur cruises ship management ltd imo 5364264 former owner pullmantur cruises empress ltd. imo identification numbers ships companies registered owners assigned ihs markit previously lloyd register-fairplay new vessels imo number assigned hull construction generally upon keel laying many vessels fall outside mandatory requirements solas numbers allocated lloyd register ihs markit numerical series including fishing vessels commercial yachts imo number made three letters imo followed seven-digit number consists six-digit sequential unique number followed check digit integrity imo number verified using check digit done multiplying first six digits factor 2 7 corresponding position right left rightmost digit sum check digit example imo 9074729 9× 7 0× 6 7× 5 4× 4 7× 3 2× 2 139 01718423143
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Databases
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egress filtering computer networking egress filtering practice monitoring potentially restricting flow information outbound one network another typically information private tcp/ip computer network internet controlled tcp/ip packets sent internal network examined via router firewall similar edge device packets meet security policies allowed leave – denied egress egress filtering helps ensure unauthorized malicious traffic never leaves internal network corporate network typical recommendations traffic except emerging select set servers would denied egress restrictions made select protocols http email dns allowed user workstations would need configured either manually via proxy auto-config use one allowed servers proxy corporate networks also typically limited number internal address blocks use edge device boundary internal corporate network external networks internet used perform egress checks packets leaving internal network verifying source ip address outbound packets within range allocated internal address blocks egress filtering may require policy changes administrative work whenever new application requires external network access reason egress filtering uncommon feature consumer small business networks
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Computer security
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iglue iglue experimental database detailed search options containing entities information editing tool organizes interrelated images videos individuals institutions objects websites geographical locations cohesive data structures important components iglue system flexible database contains semantic elements entities relational connections in4 kft established august 2007 company specialised development online applications based university researches participation young university researchers power dream ventures financial investor
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Computational linguistics
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cardinality data modeling database design cardinality fundamental principle one data aspect respect another critical feature relationship one must precise exact order explain aspect links together relational model tables related one-to-many many-to-many one-to-zero-or-one etc.. said cardinality given table relation another example consider database designed keep track hospital records database could many tables like model one-to-one relationship mostly used split table two order provide information concisely make understandable hospital example relationship could used keep apart doctors unique professional information administrative details data modeling collections data elements grouped data tables contain groups data field names called database attributes tables linked key fields primary key assigns field special order table example doctor last name field might assigned primary key doctor table people last name organized alphabetically according first three letters first name table also foreign key indicates field linked primary key another table complex data model involve hundreds related tables renowned computer scientist edgar f. codd created systematic method decompose organize relational databases codd steps organizing database tables keys called database normalization avoids certain hidden database design errors delete anomalies update anomalies real life process database normalization ends breaking tables larger number smaller tables real world data modeling critical data grows voluminous tables linked keys must used speed programmed retrieval data data model poorly crafted even computer applications system million records give end-users unacceptable response time delays reason data modeling keystone skills needed modern software developer entity–relationship model proposes technique produces entity–relationship diagrams erds employed capture information data model entity types relationships cardinality crow foot shows one-to-many relationship alternatively single line represents one-to-one relationship object-oriented application programming paradigm related database structure design uml class diagrams may used object modeling case object relationships modeled using uml associations multiplicity used associations denote cardinality examples
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Databases
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dataflow dataflow term used computing various meanings depending application context term used context software architecture data flow relates stream processing reactive programming dataflow software paradigm based idea disconnecting computational actors stages pipelines execute concurrently dataflow also called stream processing reactive programming multiple data-flow/stream processing languages various forms see stream processing data-flow hardware see dataflow architecture alternative classic von neumann architecture obvious example data-flow programming subset known reactive programming spreadsheets user enters new values instantly transmitted next logical actor formula calculation distributed data flows also proposed programming abstraction captures dynamics distributed multi-protocols data-centric perspective characteristic data flow programming promotes high-level functional specifications simplifies formal reasoning system components hardware architectures dataflow major topic computer architecture research 1970s early 1980s jack dennis mit pioneered field static dataflow architectures designs use conventional memory addresses data dependency tags called static dataflow machines machines allow multiple instances routines executed simultaneously simple tags could differentiate designs use content-addressable memory called dynamic dataflow machines arvind use tags memory facilitate parallelism data flows around computer components computer gets entered input devices leave output devices printer etc. dataflow network network concurrently executing processes automata communicate sending data channels see message passing kahn process networks named gilles kahn processes determinate implies determinate process computes continuous function input streams output streams network determinate processes determinate thus computing continuous function implies behavior networks described set recursive equations solved using fixed point theory movement transformation data represented series shapes lines
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Computer architecture
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attack killer tomatoes 1986 video game attack killer tomatoes computer game released 1986 sinclair spectrum amstrad cpc msx based 1978 comedy film name player takes control wimp plasbot works tomato puree plant must rid plant mutated killer tomatoes referred title wimp plasbot checked 9:00 begin another day work discovered tomatoes mutated wimp must destroy killer tomatoes ensuring pizza parlours still supplied puree bouncing ones player must control wimp explores various isometric 3d rooms attempts destroy mutated killer tomatoes three different types tomato found factory killer tomatoes walk around legs square patterns kill wimp touch wimp must destroy tomatoes crushing hammer found somewhere factory second type tomato bounce wimp must stop bouncing squirting tomato sauce take crusher keep supply tomato puree third type tomato sit floor factory wimp touches cause time clock accelerate short clocking time reached killer tomatoes destroyed player loses punch cards found around factory give player extra time reviews fairly positive crash giving 89 sinclair rating 8/10 zx computing rating great crash said game despite awfulness movie name akt excellent game though owe quite lot previous releases rachael smith sinclair said ... converting film nominated worst vegetable movie time global created tie-in far better original deserved far better many superior films received zx computing said killer tomatoes quite complex professionally produced game keep occupied quite similarity knight lore inspired titles left feeling n't really offer anything n't seen
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Computer architecture
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web services invocation framework web services invocation framework wsif supports simple java api invoking web services matter services provided framework allows maximum flexibility invocation web services description language wsdl -described service using wsif wsdl become centerpiece integration framework accessing software running diverse platforms using widely varying protocols precondition software needs described using wsdl included description binding client wsif framework provider wsif defines comes packaged providers local java enterprise javabeans ejb java message service jms java ee connector architecture jca protocols means client define ejb java message service-accessible service directly wsdl binding access transparently using wsif using api one would use soap service local java class wsdl binding defines map abstract porttype real service format protocol example soap binding defines encoding style soapaction header namespace body targeturi forth wsdl allows multiple implementations web service multiple ports share porttype words wsdl allows interface bindings example soap iiop wsif provides api allow client code access available binding client code written porttype deployment configuration setting code choice port binding uses wsif uses providers support multiple wsdl bindings provider piece code supports wsdl extension allows invocation service particular implementation wsif providers use j2se jar service provider specification making discoverable runtime clients utilize new implementations delegate choice port infrastructure runtime allows implementation chosen basis quality service characteristics business policy wsif defines additional binding extensions enterprise javabean ejbs local java classes software accessible message queues using java message service jms api software invoked using java connector architecture also described wsdl wsif packaged providers allow transparent invocation software given corresponding wsdl description wsif enables developers interact abstract representations web services wsdl descriptions instead working directly simple object access protocol soap apis usual programming model wsif developers work programming model regardless web service implemented accessed wsif allows stubless completely dynamic invocation web service based upon examination meta-data service runtime also allows updated implementations binding plugged wsif runtime allows calling service defer choosing binding runtime finally wsif closely based upon wsdl invoke service described wsdl complicated enterprise software system consists various pieces software developed period tens years ejbs legacy apps accessed using java connector architecture soap services hosted external servers old code accessed messaging middleware – necessary write software applications use pieces useful things yet differences protocols mobility software etc get way software one uses moves different server code breaks soap libraries one uses change example one moves using apache soap apache axis – code breaks uses deprecated soap api something previously accessible ejb available messaging middleware via jms need fix code uses software one ejb offered soap service external clients using soap results performance penalty compared accessing ejb directly soap baseline protocol platform language independence n't java clients able take advantage fact software accessing really ejb java customers pay performance penalty since use soap accommodate non-java clients wsif fixes problems allowing wsdl used normalized description disparate software allows one access software manner independent protocol location whether soap ejb jms potentially .net software frameworks api centered around wsdl used access functionality lets one write code adapts changes easily separation api actual protocol also means flexibility switch protocols location etc without even recompile client code externally available soap service becomes available ejb one switch using rmi/iiop changing service description wsdl without make modification applications use service exploit wsdl extensibility capability offer multiple bindings service deciding binding runtime etc axis implementation soap includes server-side infrastructure deploying web service implementations routing soap messages clients implementations also implements jax-rpc specification invoking soap services wsif similar client piece axis used invoking services however wsif api wsdl-driven protocol independent allows protocol-specific code providers plugged invoking soap services wsif packaged axis provider uses axis apis i.e jax-rpc invocation wsif operates abstract level axis jax-rpc api invoking xml-based rpc services – essentially current scope limited invocation soap services wsif api invoking wsdl-described services whether happen soap services example wsif defines wsdl bindings ejbs enterprise software accessible using jms java connector architecture well local java classes described first-class wsdl services invoked using protocol-independent wsif api
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Web technology
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program slicing computer programming program slicing computation set program statements program slice may affect values point interest referred slicing criterion program slicing used debugging locate source errors easily applications slicing include software maintenance optimization program analysis information flow control slicing techniques seeing rapid development since original definition mark weiser first slicing static i.e. applied source code information source code bogdan korel janusz laski introduced dynamic slicing works specific execution program given execution trace forms slicing exist instance path slicing based original definition weiser informally static program slice consists statements program p may affect value variable v statement x slice defined slicing criterion c= x v x statement program p v variable x static slice includes statements affect value variable v statement x possible input static slices computed backtracking dependencies statements specifically compute static slice x v first find statements directly affect value v statement x encountered recursively statement affect value v statement x compute slices variables z affect value v. union slices static slice x v example consider c program let compute slice write sum sum value sum directly affected statements sum sum w n 1 int sum 0 n 1 slice write sum sum union three slices int sum 0 statement dependencies fairly easy see slice sum sum w sum consists sum sum w int sum 0 two prior statements affect value sum sum sum w similarly slice sum sum w contains 1 n ++i slice sum sum w w contains statement int w 7 union statements executable code make slice executable slice merely add end brace loop declaration resulting static executable slice shown original code static executable slice criteria codice_1 sum new program shown fact static slicing techniques including weiser technique also remove codice_1 statement since statement codice_1 value codice_4 dependent statement often slice particular statement x include one variable v set variables statement x slice x v union slices criteria x v v variable set v. fast scalable yet slightly less accurate slicing approach extremely useful number reasons developers low cost practical means estimate impact change within minutes versus days important planning implementation new features understanding change related parts system also provide inexpensive test determine full expensive analysis system warranted fast slicing approach open new avenues research metrics mining histories based slicing slicing conducted large systems entire version histories practical time frames opens door number experiments empirical investigations previously costly undertake makes use information particular execution program dynamic slice contains statements actually affect value variable program point particular execution program rather statements may affected value variable program point arbitrary execution program example clarify difference static dynamic slicing consider small piece program unit iteration block containing if-else block statements codice_5 codice_6 blocks effect variable case static slicing since whole program unit looked irrespective particular execution program affected statements blocks would included slice case dynamic slicing consider particular execution program wherein codice_5 block gets executed affected statements codice_6 block get executed particular execution case dynamic slice would contain statements codice_5 block
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Programming language topics
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eset nod32 eset nod32 antivirus commonly known nod32 antivirus software package made slovak company eset eset nod32 antivirus sold two editions home edition business edition business edition packages add eset remote administrator allowing server deployment management mirroring threat signature database updates ability install microsoft windows server operating systems acronym nod stands nemocnica na okraji disku hospital end disk pun related czechoslovak medical drama series nemocnice na kraji města hospital end city first version nod32 called nod-ice dos-based program created 1987 miroslav trnka peter paško time computer viruses started become increasingly prevalent pcs running dos due limitations os lack multitasking among others n't feature on-demand/on-access protection features current versions besides virus scanning cleaning functionality featured heuristic analysis increasing popularity windows environment advent 32-bit cpus shift pc market increasing popularity internet came need completely different antivirus approach well thus original program re-written christened nod32 emphasize radical shift previous version win32 system compatibility initially program gained popularity workers eastern european countries eset based slovakia though program abbreviation originally pronounced individual letters worldwide use program led common single-word pronunciation sounding like english word nod additionally 32 portion name anachronism release 64-bit version windows 7 era company reached 10000th update virus definitions june 25 2014 march 10 2010 eset released eset mail security microsoft exchange server contains antimalware antispam modules supports microsoft exchange 5.5 2000 2003 2007 2010 eset mobile security replacement eset mobile antivirus provided anti-malware antispam functionality eset mobile security contains features older product adds new anti-theft features sim locking remote wipe well security audit firewall versions windows mobile symbian os available september 2010 home enterprise users eset remote administrator central management console designed allow network administrators manage eset software across corporate network november 5 2007 eset released internet security suite eset smart security version 3.0 compete security suites companies mcafee symantec avg kaspersky eset smart security incorporates anti-spam bidirectional firewall along traditional anti-malware features eset nod32 antivirus march 2 2009 eset smart security version 4.0 released adding integration eset sysinspector support mozilla thunderbird windows live mail new self-defense module updated firewall module eset sysrescue wizard creating bootable cd usb flash drives initially compatibility problems eset smart security 4.0 windows vista service pack 2 remedied update august 17 2010 eset smart security version 4.2 released new features enhancements changes september 14 2011 eset smart security version 5.0 released january 15 2013 eset smart security version 6.0 released version included anti-theft feature tracking lost misplaced stolen laptop october 16 2013 eset smart security version 7.0 released offers enhanced operation memory scanning blocks misuses known exploits october 2 2014 eset smart security version 8.0 released adds exploit blocking java botnet protection october 13 2015 eset smart security version 9.0 released eset sysinspector diagnostic tool allows in-depth analysis various aspects operating system including running processes registry content startup items network connections anti-stealth technology used discover hidden objects rootkits master boot record boot sector registry entries drivers services processes sysinspector logs standard xml files submitted experts analysis two logs compared find set items common logs log file saved service script removing malicious objects computer eset sysrescue live linux-based bootable live cd/usb image used boot clean heavily infected computers independent installed operating system program offered free charge download updates network connection present eset released free standalone removers malware widespread mebroot june 1 2010 first release candidate eset file security microsoft windows server v4.3 made available public program updated version eset nod32 antivirus business edition designed microsoft windows server operating systems contains revised user interface automatic exclusions critical directories files unspecified optimizations operation servers april 22 2010 eset mobile security windows mobile symbian os went public beta home edition released september 2 2010 january 20 2011 business edition went beta april 29 2011 eset beta test version android released august 10 2011 release candidate made available december 2 2009 eset nod32 antivirus 4 mac os x desktop eset nod32 antivirus 4 linux desktop released public testing eset stated release automatically detects cleans cross-platform malware scans archives automatically scans removable media usb flash drives mounted performs real-time scanning provides reports offers gui similar microsoft windows version second beta test versions released january 9 2010 third june 10 2010 september 13 2010 eset released eset nod32 antivirus mac os x business edition announced release candidate eset cybersecurity mac os x september 24 2010 eset released release candidate eset cybersecurity mac os x january 21 2011 eset released release candidate eset nod32 antivirus linux desktop may 5 2011 eset released beta test version eset smart security 5.0 beta version adds parental control cloud-based file reputation service gamer mode hips improvements antispam firewall removable media control functions june 14 2011 eset released release candidate eset smart security version 5.0 august 5 2014 eset smart security version 8.0 public beta 1 released offers enhanced exploit blocking botnet detection eset mobile antivirus aimed protecting smartphones viruses spyware adware trojans worms rootkits unwanted software also provided antispam filtering sms messages versions windows mobile symbian os available eset discontinued eset mobile antivirus january 2011 provides eset mobile security free upgrade licensed users eset mobile antivirus 1 february 2010 eset discontinued version 2.7 nod32 antivirus previous version nod32 antivirus removed eset website including product pages e-store version 2.7 last version supporting microsoft 95/98/me novell netware operating systems virus signature database updates customer support discontinued february 1 2012 network nod32 clients update central mirror server network nod32 antivirus holds icsa labs certifications nod32 accumulated one hundred eleven vb100 awards virus bulletin failed receive award three times comparative report virus bulletin published 2 september 2008 nod32 detected 94.4 malware 94.7 spyware stood competitors like norton internet security zonealarm windows live onecare avira antivir rap averages quadrant december 2011 june 2012 virus bulletin found eset pretty much level 94 noted ability block spam phishing earning award award 19 antivirus companies able acquire 28 april 2008 robert vamosi cnet.com reviewed version 3.0 nod32 gave score 3.5/5 6 march 2009 seth rosenblatt download.com reviewed 4.0 version nod32 gave rating 4.6/5 15 september 2011 seth rosenblatt cnet reviewed 5.0 version nod32 gave rating 5/5
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Computer security
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michael jackson moonwalker michael jackson moonwalker name several video games based 1988 michael jackson film moonwalker u.s. gold published various games home computers released 1989 sega developed two similarly themed beat 'em video games 1990 one released arcades another released mega drive/genesis master system games stories loosely follow story film michael jackson must rescue kidnapped children evil mr. big incorporate synthesized versions musician songs versions game released popular 8-bit 16-bit home computers time developed two small software houses irish emerald software ltd american keypunch software published u.k. company u.s. gold game features four different levels first level top-down maze-style level next level similar gameplay riding motorcycle collecting tokens third level side-scrolling level based smooth criminal clip player collects ammunition shoots gangsters openings player character last level involves morphing robot shooting soldiers openings player controlling crosshair different home computer version arcade video game sega programming triumph international audiovisuals help jackson released sega system 18 hardware game suffered sega suicide battery arcade board battery accidentally otherwise renders game unplayable end lifespan arcade distinctively different gameplay computer console counterparts focusing beat 'em gameplay elements rather platform game essentially beat-em-up although jackson attacks magic powers instead physical contact ability shoot short-ranged magic power enemies magic power charged holding attack button increase range damage magic power close enemies jackson executes spinning melee attack using magic power cabinet supports three people play simultaneously three players play jackson dressed suit white player 1 red player 2 black player 3 jackson special attack termed dance magic three different dance routines may performed player starts one three attacks per credit depending machine set bubbles chimpanzee michael real-life pet appears level collected rescued chimp transforms michael robotic version pop singer ability shoot laser bursts missiles absorb significantly damage home versions game released sega mega drive/genesis master system home video game systems though gameplay completely different arcade version version also rated pegi release virtual console never materialized never specified version considered rerelease home console versions actually based evolved version home computer version game gameplay somewhat similar shinobi series contrast arcade version three-quarters view shooter/fighter type game game involves player controlling pop star quest save kids kidnapped mr. big game levels music borrowed film though many music tracks taken jackson thriller album well player ability destroy enemies making dance jackson become robot rescuing certain child grabbing comet falls sky gameplay focused finding children resemble katie movie scattered throughout level behind objects doors objects empty contain enemies jackson standard attack stylized high kick commonly incorporated dance routines player continues hold kick button moves jackson backwards performs moonwalk dance move critical reviews mixed positive sinclair compared spectrum version game gauntlet operation wolf saying well animated surprising amount fun megatech said megadrive version addictive platform game excellent graphics mega magazine placed game number 91 list best megadrive games time saying average jackson later would go cameo role sega space channel 5 music/rhythm games dreamcast playstation 2 jackson also appeared secret character
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Computer architecture
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process computing computing process instance computer program executed one many threads contains program code activity depending operating system os process may made multiple threads execution execute instructions concurrently computer program passive collection instructions process actual execution instructions several processes may associated program example opening several instances program often results one process executed multitasking method allow multiple processes share processors cpus system resources cpu core executes single task time however multitasking allows processor switch tasks executed without wait task finish depending operating system implementation switches could performed tasks perform input/output operations task indicates switched hardware interrupts common form multitasking time-sharing time-sharing method allow high responsiveness interactive user applications time-sharing systems context switches performed rapidly makes seem like multiple processes executed simultaneously processor seeming execution multiple processes simultaneously called concurrency security reliability modern operating systems prevent direct communication independent processes providing strictly mediated controlled inter-process communication functionality general computer system process consists said following resources operating system holds information active processes data structures called process control blocks subset resources typically least processor state may associated process threads operating systems support threads child processes operating system keeps processes separate allocates resources need less likely interfere cause system failures e.g. deadlock thrashing operating system may also provide mechanisms inter-process communication enable processes interact safe predictable ways multitasking operating system may switch processes give appearance many processes executing simultaneously parallel though fact one process executing one time single cpu unless cpu multiple cores multithreading similar technologies used usual associate single process main program child processes spin-off parallel processes behave like asynchronous subroutines process said resources image program memory one resource however multiprocessing systems many processes may run share reentrant program location memory process said image program processes often called tasks embedded operating systems sense process task something takes time opposed memory something takes space description applies processes managed operating system processes defined process calculi process requests something must wait blocked process blocked state eligible swapping disk transparent virtual memory system regions process memory may really disk main memory time note even portions active processes/tasks executing programs eligible swapping disk portions used recently parts executing program data physical memory associated process active operating system kernel allows multitasking needs processes certain states names states standardised similar functionality processes communicate called inter-process communication ipc processes frequently need communicate instance shell pipeline output first process need pass second one process preferred well-structured way using interrupts even possible two processes running different machines operating system os may differ one process therefore mediator called protocols needed early 1960s computer control software evolved monitor control software example ibsys executive control software time computers got faster computer time still neither cheap fully utilized environment made multiprogramming possible necessary multiprogramming means several programs run concurrently first one program ran single processor result underlying uniprocessor computer architecture shared scarce limited hardware resources consequently concurrency serial nature later systems multiple processors multiple programs may run concurrently parallel programs consist sequences instructions processors single processor run one instruction time impossible run programs time program might need resource input device large delay program might start slow operation sending output printer would lead processor idle unused keep processor busy times execution program halted operating system switches processor run another program user appear programs run time hence term parallel shortly thereafter notion program expanded notion executing program context concept process born also became necessary invention re-entrant code threads came somewhat later however advent concepts time-sharing computer networks multiple-cpu shared memory computers old multiprogramming gave way true multitasking multiprocessing later multithreading
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Operating systems
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memory segmentation memory segmentation computer primary memory management technique division computer primary memory segments sections computer system using segmentation reference memory location includes value identifies segment offset memory location within segment segments sections also used object files compiled programs linked together program image image loaded memory segments usually correspond natural divisions program individual routines data tables segmentation generally visible programmer paging alone different segments may created different program modules different classes memory usage code data segments certain segments may shared programs segmentation originally invented method system software could isolate different software processes tasks data using intended increase reliability systems running multiple processes simultaneously x86-64 architecture considered legacy x86-64-based modern system software n't use memory segmentation instead handle programs data utilizing memory-paging also serves way memory protection however x86-64 implementations still support backward compatibility reasons moreover segmentation user end memory management scheme system using segmentation computer memory addresses consist segment id offset within segment hardware memory management unit mmu responsible translating segment offset physical address performing checks make sure translation done reference segment offset permitted segment length set permissions example read write execute associated process allowed make reference segment type reference allowed permissions offset within segment within range specified length segment otherwise hardware exception segmentation fault raised segments may also used implement virtual memory case segment associated flag indicating whether present main memory segment accessed present main memory exception raised operating system read segment memory secondary storage segmentation one method implementing memory protection paging another combined size memory segment generally fixed may small single byte segmentation implemented several different ways different hardware without paging intel x86 memory segmentation fit either model discussed separately also greater detail separate article associated segment information indicates segment located memory— segment base program references memory location offset added segment base generate physical memory address implementation virtual memory system using segmentation without paging requires entire segments swapped back forth main memory secondary storage segment swapped operating system allocate enough contiguous free memory hold entire segment often memory fragmentation results enough contiguous memory even though may enough total instead actual memory location segment information includes address page table segment program references memory location offset translated memory address using page table segment extended simply allocating another memory page adding segment page table implementation virtual memory system using segmentation paging usually moves individual pages back forth main memory secondary storage similar paged non-segmented system pages segment located anywhere main memory need contiguous usually results reduced amount input/output primary secondary storage reduced memory fragmentation burroughs corporation b5000 computer one first implement segmentation perhaps first commercial computer provide virtual memory based segmentation later b6500 computer also implemented segmentation version architecture still use today unisys clearpath libra servers ge-645 computer modification ge-635 segmentation paging support added designed 1964 support multics intel iapx 432 begun 1975 attempted implement true segmented architecture memory protection microprocessor prime stratus apollo ibm system/38 ibm as/400 computers use memory segmentation memory segmentation used early x86 processors beginning intel 8086 provide protection program running processors access segment restrictions segment identified starting location length checking segmentation intel 80286 later provides protection introduction 80286 intel retroactively named sole operating mode previous x86 cpu models real mode introduced new protected mode protection features backward compatibility x86 cpus start real mode memory protection fixed 64 kib segments 20-bit 1024 kib addressing 80286 later processor must switched another mode software order use full address space advanced mmu features x86 implementation segmentation segment table rather pointing page table segment contains segment address linear memory address mapped physical address using separate page table unlike paged implementations segmentation prevents segments dynamically growing size x86-64 architecture use segmentation long mode 64-bit mode x86-64 architecture considered legacy x86-64-based modern system software n't use memory segmentation instead handle programs data utilizing memory-paging also serves way memory protection though x86-64 implementations still support backward compatibility reasons four segment registers cs ss ds es forced 0 limit 2 segment registers fs gs still nonzero base address allows operating systems use segments special purposes
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Operating systems
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dragon knight video game dragon knight ドラゴンナイト fantasy-themed eroge role-playing video game original entry dragon knight franchise originally developed published elf corporation 1989 remake created nec avenue 1995 versions released japan game adapted anime film 1991 followed dragon knight ii 1990 gameplay-wise dragon knight dungeon crawler typical era similar early wizardry games exploration combat shown first-person perspective using 2d engine combat game turn-based enemies encountered randomly similar system also used first sequel new floor mazes becomes sophisticated however helpful mini-map grid coordinates enemies getting stronger fights first game difficult unbalanced protagonist attack defend use spells items fight monsters three kingdom strawberry fields ストロベリーフィールズ place inhabited women goddess tower protected land people generations one day monstrous dragon knights corrupted evil led demon gazelbaan ゲイゼルバーン descended upon tower people strawberry fields suddenly find threatened army monsters turned goddess aquarina アクァーリナー stone captured warrior women demanding six gems source magical power goddess delivered else would kill hostages answering plea help queen luna ルナ voiced noriko hidaka young warrior traveler yamato takeru ヤマト・タケル voiced akira kamiya takes luna mother voiced rei sakuma floor tower captured females takeru rescue rapists game originally released 1989 pc88 pc98 msx followed sharp x68000 version 1990 1995 remake dragon knight graffiti pc engine developed released nec avenue two soundtracks dragon knight treasure king water chapter ドラゴンナイト～水の宝王篇～ pc engine world — dragon knight graffiti released japan datam polystar 1990 nec avenue distributed nippon columbia 1995 respectively ova anime adaptation released polystar vhs ld 1991 soft cel pictures distributed english version vhs format also re-released dvd 2003 cast included yasunori matsuno takeru yūko mizutani luna release famicom tsūshin scored pc engine remake 22 40 also giving 8 10 reader cross review information russian article square faction japanese wikipedia
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Computer architecture
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brendan gregg brendan gregg kernel performance engineer netflix known work systems performance analysis previously worked sun microsystems oracle corporation joyent gregg born newcastle new south wales attended university newcastle australia working technical instructor sun microsystems later consultant hired join sun fishworks team san francisco october 2010 left oracle position lead performance engineer joyent march 2014 became senior performance architect netflix gregg one leading experts dtrace creator dtracetoolkit author books dtrace systems performance also star shouting data center viral video november 2013 awarded lisa outstanding achievement award contributions field system administration particularly groundbreaking work systems performance analysis methodologies investigates writes linux performance new blog gregg developed various methodologies performance analysis notably use method methodology short utilization saturation errors method also created visualization types aid performance analysis including latency heat maps utilization heat maps subsecond offset heat maps flame graphs
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Operating systems
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pac611 socket pac611 611 pin microprocessor socket designed interface intel itanium 2 processor rest computer usually via motherboard provides electrical interface well physical support socket designed support microprocessor module socket pac611 introduced intel second generation itanium 2002 supported bus speeds 200 mhz double-pumped socket pac611 processors reach speeds 1.66 ghz
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Computer architecture
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apttus apttus american business-to-business software provider specializing business process automation company provides calls “ middle office ” solutions utilizing artificial intelligence optimize various financial commercial functions quote-to-cash revenue management e-commerce management apttus ’ software originally developed leverage salesforce customer relationship management platform since integrated microsoft azure ibm cloud well september 2018 private equity firm thoma bravo purchased majority stake apttus resulted significant turnover executive ranks thoma bravo installed new ceo cfo chief legal officer chief people officer vice president finance corporate controller end 2018 apttus founded 2006 kirk krappe neehar giri kent perkocha three co-founders reportedly developed company ideas written napkins laundry room krappe served company ’ first ceo giri chief solutions officer perkocha chief customer officer company bootstrapped took outside funding 2013 raised 37 million series financing group investors including k1 capital iconiq salesforce time 2018 buyout apttus received total 404 million investment capital five rounds fundraising gave company valuation approximately 1.3 billion september 2016 despite publicly discussing likelihood initial public offering 2016 apttus never went public acquired thoma bravo 2015 acquisition apttus rival steelbrick salesforce early apttus investor widely blamed apttus ’ inability complete ipo find buyer favorable terms july 2018 krappe departed apttus little warning move later reported driven accusations sexual assault misrepresentations company ’ financial performance allegations became public november 1 2018 publication business insider investigative piece highlighted company sales retreat one palmilla resort near cabo san lucas mexico krappe reportedly sexually assaulted 26 year-old female business development employee allegations accused krappe presenting misleading data apttus ’ size financial health time report “ several ” sexual harassment claims underway well three lawsuits financial misrepresentation issues
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Distributed computing architecture
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infrastructure service infrastructure service iaas online services provide high-level apis used dereference various low-level details underlying network infrastructure like physical computing resources location data partitioning scaling security backup etc hypervisor xen oracle virtualbox oracle vm kvm vmware esx/esxi hyper-v lxd runs virtual machines guests pools hypervisors within cloud operational system support large numbers virtual machines ability scale services according customers varying requirements typically iaas involves use cloud orchestration technology like open stack apache cloudstack open nebula manages creation virtual machine decides hypervisor i.e physical host start enables vm migration features hosts allocates storage volumes attaches vms usage information billing lots alternative hypervisors linux containers run isolated partitions single linux kernel running directly physical hardware linux cgroups namespaces underlying linux kernel technologies used isolate secure manage containers containerisation offers higher performance virtualization hypervisor overhead also container capacity auto-scales dynamically computing load eliminates problem over-provisioning enables usage-based billing iaas clouds often offer additional resources virtual-machine disk-image library raw block storage file object storage firewalls load balancers ip addresses virtual local area networks vlans software bundles nist definition cloud computing defines infrastructure service according internet engineering task force ietf basic cloud-service model providers offering infrastructure — virtual machines resources — service subscribers iaas-cloud providers supply resources on-demand large pools equipment installed data centers wide-area connectivity customers use either internet carrier clouds dedicated virtual private networks deploy applications cloud users install operating-system images application software cloud infrastructure model cloud user patches maintains operating systems application software cloud providers typically bill iaas services utility computing basis cost reflects amount resources allocated consumed
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Distributed computing architecture
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fireblade company fireblade acquired stackpath israeli company founded 2008 provides website security traffic management software based cloud ’ two tier saas application protects websites ddos attacks data scrapping improves website health security performance fireblade founded shay rapaport erez azaria ceo cto respectively offers integration cpanel whm service offers protection ddos attacks spam scrapping cms vulnerability brute force anda reputational behavioral firewalls also offers dynamic optimization 30 points presence tier-1 cdn tools
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Computer security
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ext3cow ext3cow third extended filesystem copy-on-write open source versioning file system based ext3 file system versioning implemented block-level copy-on-write shares many performance characteristics ext3 ext3cow provides time-shifting interface permits real-time continuous view data past time-shifting novel interface introduced ext3cow allowing users navigate access past namespaces adding time component commands ext3cow designed platform compliance versioning auditability requirements recent us electronic record retention legislation sarbanes-oxley hipaa version ext3cow linux 2.6 kernel released march 30 2007 details ext3cow implementation found 2005 paper
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Computer file systems
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enough operating system enough operating system jeos pronounced juice paradigm customizing operating systems fit needs particular application software appliance platform includes operating system components required support particular application third-party components contained appliance e.g. kernel makes appliance smaller faster boot execute particular application potentially secure application running full general-purpose os typically jeos consist following important differentiate true fully minimalized os install profiles forced example security hardening tools representing recovery console images jeos richer install profiles designed built wider audience usage vm/va creators users easily perform needed installation configuration tasks
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Operating systems
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unix programming environment unix programming environment first published 1984 prentice hall book written brian w. kernighan rob pike bell labs considered important early document unix operating system book addresses unix philosophy small cooperating tools standardized inputs outputs kernighan pike give brief description unix design unix philosophy authors write goal book communicate unix programming philosophy book starts introduction unix beginners next goes basics file system shell reader led topics ranging use filters use c programming robust unix applications basics grep sed make awk book closes tutorial making programming language parser yacc use troff ms mm format documents preprocessors tbl eqn pic making man pages man macro set appendices cover ed editor abovementioned programming language named hoc stands high-order calculator although unix still exists decades publication book book describes already mature unix 1984 unix already development 15 years since 1969 published peer-reviewed journal 10 years earlier sosp 1974 unix timesharing system least seven official editions manuals published see version 7 unix 1984 several commercial academic variants unix already existed e.g. xenix sunos bsd unix system v hp-ux year earlier ritchie thompson prestigious turing award work unix book written unix starting already popular enough worthy book published masses new users coming retrospect 1984 early stage unix evolution respects end unix evolution least bell labs important unix variants already forked research unix earlier system v published 1983 bsd based 1979 seventh edition unix commercial unix variants based system v bsd combination eighth edition unix came right book development unix bell labs ninth tenth edition never made outside bell labs effort evolved plan 9 bell labs book written ansi c first drafted programs follow older k r style however source code available book website updated ansi c conformance technical editor ben everard linux voice magazine praised book providing relevant documentation despite 30 years old good book aspiring programmers n't know much linux
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Operating systems
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browserless web browserless web communication web applications without need web browser term coined article network world referring mainly business-to-business interaction
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Web technology
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outline computer security following outline provided overview topical guide computer security computer security – security applied computing devices computers smartphones well computer networks private public networks including whole internet field covers processes mechanisms digital equipment information services protected unintended unauthorized access change destruction growing importance line increasing reliance computer systems societies worldwide computer security includes measures taken ensure integrity files stored computer server well measures taken prevent unauthorized access stored data securing physical perimeter computer equipment authentication users computer accounts accessing data providing secure method data transmission computer security described following variety threats combined rapid development new threats made cyber insecurity removal information assurance 'status quo long man continues use computer man also takes interest manipulating modifying creating bypassing 'rules 'security standards common effective method violating computer security protocols phishing phishing process providing cloned login page site victim uses example google gmail user enters his/her login information data captured access victims account gained many corporations executive mid-ranking managers even low level staff many current u.s. corporations idea malicious user quietly passively intercepting communications strong motivation theft intellectual property often victims phishing either never become aware privacy breached many months pass become aware privacy lost methods computer network attack computer network exploitation social engineering frequent method attack take form phishing spear phishing corporate government world well counterfeit websites hid spoofing keylogger access control – selective restriction access place resource act accessing may mean consuming entering using permission access resource called authorization application security data security – protecting data database destructive forces unwanted actions unauthorized users independent organization evaluates rates antivirus security suite software microsoft windows android operating systems according variety criteria every month researchers publish results testing list products awarded certification organisation based magdeburg germany internet police – police secret police departments law enforcement agencies charge policing internet major purposes internet police depending state fighting cybercrime well censorship propaganda monitoring manipulating online public opinion rubber-hose cryptanalysis
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Computer security
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cherax snowden cherax snowden species crayfish west papua indonesia oinsok river drainage sawiat district chendravasikh kepala burung peninsulas wild live freshwater river tributaries popular freshwater aquarium pet across asia europe north america orange-tipped claws specimens previously misidentified members cherax holthuisi also west papua adult body length 10 cm males 7 cm females different shades green brownish-green bluish-green predominant body color throughout lives claw tips orange first samples became known west 2006 means internet pet shops time examined professional zoologists 2015 cherax snowden new species crayfish crustacea decapoda parastacidae kepala burung vogelkop peninsula irian jaya west papua indonesia already popular pet europe east asia america name orange tip scientific species description published german zoologists institute environmental sciences university koblenz-landau landau species named edward snowden honor contribution freedom speech
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Computer security
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peter macdonald computer programmer peter macdonald canadian software engineer best known creator softlanding linux system sls widely regarded first complete linux distribution work served foundation wine also created tcl web browser browsex pdqi suite tcl utilities current projects include jsish embeddable javascript interpreter builtin type-checking peter charles macdonald born victoria british columbia june 28 1957 graduated computer science program university victoria bsc 1989 msc 1996 master thesis decomposing linux kernel dynamically loadable modules macdonald co-developed early features linux kernel early 1990s including shared libraries pseudo terminals select call virtual consoles announced softlanding linux system sls first standalone linux install testing august 1992 15 floppy disks general release october 1992 recommending least 10 mb disk space sls became popular also drew criticism macdonald criticized trying make money free software defended linus torvalds two early linux distributions made specifically reaction sls ian murdock debian compensate sls bugs patrick volkerding slackware include installer patches n't added sls macdonald would n't allow volkerding distribute independently initial 1993 wine windows emulator based tcl/tk windowing functions macdonald wrote though later rewritten direct xlib calls macdonald founded browsex systems 1999 put version 1.0 browsex open source tcl-based cross-platform web browser meant smaller faster netscape last update browsex 2003 company renamed pdq interfaces inc. put set various tcl based utilities jsish javascript interpreter builtin sqlite json websocket zvfs support
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Operating systems
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logical volume management computer storage logical volume management lvm provides method allocating space mass-storage devices flexible conventional partitioning schemes store volumes particular volume manager concatenate stripe together otherwise combine partitions block devices general larger virtual partitions administrators re-size move potentially without interrupting system use volume management represents one many forms storage virtualization implementation takes place layer device-driver stack operating system os opposed within storage devices network volume-manager implementations share basic design start physical volumes pvs either hard disks hard disk partitions logical unit numbers luns external storage device volume management treats pv composed sequence chunks called physical extents pes volume managers hp-ux linux pes uniform size others veritas variably-sized pes split merged normally pes simply map one-to-one logical extents les mirroring multiple pes map le pes drawn physical volume group pvg set same-sized pvs act similarly hard disks raid1 array pvgs usually laid reside different disks data buses maximum redundancy system pools les volume group vg pooled les concatenated together virtual disk partitions called logical volumes lvs systems use lvs raw block devices like disk partitions creating mountable file systems using swap storage striped lvs allocate successive le different pv depending size le improve performance large sequential reads bringing bear combined read-throughput multiple pvs administrators grow lvs concatenating les shrink returning les pool concatenated les contiguous allows lvs grow without move already-allocated les volume managers allow re-sizing lvs either direction online changing size lv necessarily change size file system merely changes size containing space file system resized online recommended allows system adjust storage on-the-fly without interrupting applications pvs lvs shared span different vgs although volume managers may allow moving vgs host allows administrators conveniently bring vgs online take offline move host systems single administrative unit vgs grow storage pool absorbing new pvs shrink retracting pvs may involve moving already-allocated les pv volume managers perform movement online underlying hardware hot-pluggable allows engineers upgrade replace storage without system downtime hybrid volume volume intentionally opaquely makes use two separate physical volumes instance workload may consist random seeks ssd may used permanently store frequently used recently written data using higher-capacity rotational magnetic media long-term storage rarely needed data linux bcache dm-cache may used purpose fusion drive may used os x. zfs also implements functionality file system level allowing administrators configure multi-level read/write caching hybrid volumes present similar concept hybrid drives also combine solid-state storage rotational magnetic media volume managers also implement snapshots applying copy-on-write le scheme volume manager copy le copy-on-write table written preserves old version lv snapshot may later reconstructed overlaying copy-on-write table atop current lv unless volume management supports thin provisioning discard le origin volume written permanently stored snapshot volume snapshot volume made smaller origin common practice may render snapshot inoperable snapshots useful backing self-consistent versions volatile data table files busy database rolling back large changes operating system upgrade single operation snapshots similar effect rendering storage quiescent similar shadow copy vss service microsoft windows linux-based live cds also use snapshots simulate read-write access read-only optical disc logical volumes suffer external fragmentation underlying storage devices allocate pes contiguously reduce i/o performance slow-seeking media magnetic disks rotational media volume managers use fixed-size pes however typically make pes relatively large example linux lvm uses 4 mb default order amortize cost seeks implementations solely volume management core storage linux lvm separating abstracting away volume management file system loses ability easily make storage decisions particular files directories example certain directory entire file system permanently moved faster storage file system layout underlying volume management layer need traversed example linux would needed manually determine offset file contents within file system manually extents along data related file faster storage volume file management implemented within subsystem instead implemented separate subsystems makes overall process theoretically simpler
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Computer file systems
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internet information services internet information services iis formerly internet information server extensible web server created microsoft use windows nt family iis supports http http/2 https ftp ftps smtp nntp integral part windows nt family since windows nt 4.0 though may absent editions e.g windows xp home edition active default first microsoft web server research project european microsoft windows nt academic centre emwac part university edinburgh scotland distributed freeware however since emwac server unable handle volume traffic going microsoft.com microsoft forced develop web server iis almost every version iis released either alongside version microsoft windows versions iis prior 7.0 running client operating systems supported 10 simultaneous connections single website microsoft criticized vendors web server software including o'reilly associates netscape licensing early versions windows nt workstation edition os permitted ten simultaneous tcp/ip connections whereas expensive server edition otherwise additional features permitted unlimited connections bundled iis implied intended discourage consumers running alternative web server packages cheaper edition netscape wrote open letter antitrust division u.s. department justice regarding distinction product licensing asserted technical merit o'reilly showed user could remove enforced limits meant cripple nt 4.0 workstation web server two registry key changes trivial configuration file tweaking iis 6.0 higher support following authentication mechanisms iis 7.0 modular architecture modules also called extensions added removed individually modules required specific functionality installed iis 7 includes native modules part full installation modules individual features server uses process requests include following iis 7.5 includes following additional enhanced security features authentication changed slightly iis 6.0 iis 7 notably anonymous user named iusr_ machinename built-in account vista future operating systems named iusr notably iis 7 authentication mechanism isolated module installed uninstalled iis 8.0 offers new features targeted performance easier administration new features iis 8.5 several improvements related performance large-scale scenarios used commercial hosting providers microsoft cloud offerings also several added features related logging troubleshooting new features iis express lightweight 4.5–6.6 mb version iis available standalone freeware server may installed windows xp service pack 3 subsequent versions microsoft windows iis 7.5 express supports http https protocols portable stores configuration per-user basis require administrative privileges attempts avoid conflicting existing web servers machine iis express downloaded separately part webmatrix visual studio 2012 later visual studio 2010 earlier web developers developing asp.net apps used asp.net development server codenamed cassini default iis express serves local traffic iis releases new feature modules major version releases add new functionality following extensions available iis 7.5 according netcraft february 2014 iis market share sites 32.80 making second popular web server world behind apache http server 38.22 netcraft showed rising trend market share iis since 2012 14 february 2014 however w3techs shows different results according w3techs iis third used web server behind apache http server 1st place nginx furthermore shows consistently falling trend iis use since february 2013 netcraft data february 2017 indicates iis market share top million busiest sites 10.19 making third popular web server world behind apache 41.41 nginx 28.34 iis 4 iis 5 affected ca-2001-13 security vulnerability led infamous code red attack however versions 6.0 7.0 reported issues specific vulnerability iis 6.0 microsoft opted change behaviour pre-installed isapi handlers many culprits vulnerabilities 4.0 5.0 thus reducing attack surface iis addition iis 6.0 added feature called web service extensions prevents iis launching program without explicit permission administrator default iis 5.1 earlier run websites single process running context system account windows account administrative rights 6.0 request handling processes run context network service account significantly fewer privileges vulnerability feature custom code wo n't necessarily compromise entire system given sandboxed environment worker processes run iis 6.0 also contained new kernel http stack codice_1 stricter http request parser response cache static dynamic content according secunia iis 7 total six resolved vulnerabilities iis 6 total eleven vulnerabilities one still unpatched unpatched security advisory severity rating 2 5 june 2007 google study 80 million domains concluded iis market share 23 time iis servers hosted 49 world malware apache servers whose market share 66 study also observed geographical location dirty servers suggested cause could use unlicensed copies windows could obtain security updates microsoft blog post 28 april 2009 microsoft noted supplies security updates everyone without genuine verification 2013 mass surveillance disclosures made widely known iis particularly bad supporting perfect forward secrecy pfs especially used conjunction internet explorer possessing one long term asymmetric secret keys used establish https session make easier derive short term session key decrypt conversation even later time diffie–hellman key exchange dhe elliptic curve diffie–hellman key exchange ecdhe 2013 ones known property 30 firefox opera chromium browser sessions use nearly 0 apple safari microsoft internet explorer sessions
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Web technology
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netcentrics netcentrics corporation based herndon virginia contractor us federal government netcentrics provides enterprise cloud cybersecurity services netcentrics founded 1995 bob dixon bob dougherty company first ceo july 2017 cynthia barreda succeeded dougherty current ceo netcentrics recognized comparably 2017 2018 receiving total 13 awards including best companies dc best ceo best company diversity best company outlook 2018 barreda recognized dca live federal entrepreneur netcentrics recognized one fastest growing cybersecurity companies washington metropolitan area
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Computer security
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ralf brown interrupt list ralf brown interrupt list aka rbil x86 interrupt list ms-dos interrupt list inter comprehensive list interrupts calls hooks interfaces data structures cmos settings memory port addresses well processor opcodes special function registers x86 machines including many clones start pc era 1981 2000 still applying pcs today list covers operating systems device drivers application software documented undocumented information including bugs incompatibilities shortcomings workarounds version locale date information often detail level far beyond found contemporary literature large part covers system bioses internals operating systems dos os/2 windows well interactions widely used resource ibm pc system developers analysts well application programmers pre-windows era parts compiled information used creation several books systems programming also translated chinese japanese russian compilation proven important resource developing various closed open source operating systems including linux freedos today still used reference bios calls develop programs dos well system-level software project result research collaborative effort 650 listed contributors worldwide period 15 years 290 provided significant information 55 even original list created january 1985 janet jack others named interrupt list ms-dos subsequently maintained mailed requestors usenet ross m. greenberg 1986 since october 1987 maintained ralf d. brown researcher carnegie mellon university language technologies institute information several interrupt listings merged list order establish one comprehensive reference compilation years michael a. shiels timothy patrick farley matthias r. paul robin d. h. walker wolfgang lierz tamura jones became major contributors project providing information list project also expanded include pc development related information therefore absorbed number independently maintained lists pc i/o ports wim osterholt matthias r. paul bios cmos memory contents atley padgett peterson processor opcodes alex v. potemkin bugs harald feldmann brown paul also conducted several systematic surveys specific hard- software details among number dedicated user groups order validate info help fill gaps list originally list distributed archive named interrup various compression formats well form diffs distribution file name changed include version form internyy n issue number yy 2-digit release year 1988 mid 1989 distribution settled use zip compression archive reached size 360 kb floppy june 1991 distribution split several files following interrrp.zip naming scheme rr revision starting 26 version 91.3 p part indicator package starting letter officially named ms-dos interrupt list x86 interrupt list abbreviated inter maintainer community coined unofficial name ralf brown interrupt list abbreviated rbil 1990s publication currently revision 61 17 july 2000 almost 8 mb ascii text including close entries plus tables fully cross linked would result 3700 pages 60 lines per page condensed information printed interrupt list makes 5.5 mb 2500 pages printed project officially abandoned website still maintained 2018 new releases forthcoming long time despite fact information still pending release even inter61 release 2000 new releases planned several times 2001 2002 materialize portions new information dos pc internals provided paul circulated preliminary form development community peer-review assist operating system development
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Computer architecture
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usher software usher enterprise security platform released microstrategy inc. 2015 technology designed replace user-entered passwords biometric identity multi-step authentication methods features digital badges geo-fencing administration options service takes form mobile application allows users access physical digital space based passive identification methods facial recognition bluetooth discovery etc usher positioned password killer based moving towards security credentials tied identity place applications managed via usher include salesforce.com google apps select microsoft software security features product backed usher analytics allows administrators assess data real time identify threats behavioral abnormalities organizations use usher include
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Computer security
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goonies msx video game goonies 1986 platform game konami msx based film name music simple rendition song goonies r good enough cyndi lauper goonies platform puzzle game featuring five 'scenes successfully completed scene key word given thus player continue game point time
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Computer architecture
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intel management engine intel management engine also known manageability engine autonomous subsystem incorporated virtually intel processor chipsets since 2008 located platform controller hub modern intel motherboards part intel active management technology allows system administrators perform tasks machine remotely system administrators use turn computer login remotely computer regardless whether operating system installed intel management engine always runs long motherboard receiving power even computer turned ime attractive target hackers since top level access devices completely bypasses operating system intel released much information intel management engine prompting speculation may include backdoor electronic frontier foundation voiced concern ime amd processors similar feature called amd secure technology subsystem primarily consists proprietary firmware running separate microprocessor performs tasks boot-up computer running asleep long chipset soc connected current via battery power supply continues run even system turned intel claims required provide full performance exact workings largely undocumented code obfuscated using confidential huffman tables stored directly hardware firmware contain information necessary decode contents intel main competitor amd incorporated equivalent amd secure technology formally called platform security processor virtually post-2013 cpus starting 11 based intel quark x86-based 32-bit cpu runs minix 3 operating system state stored partition spi flash using embedded flash file system effs previous versions based arc core management engine running threadx rtos versions 1.x 5.x used arctangent-a4 32-bit instructions whereas versions 6.x 8.x used newer arcompact mixed 32- 16-bit instruction set architecture starting 7.1 arc processor could also execute signed java applets mac ip address out-of-band interface direct access ethernet controller one portion ethernet traffic diverted even reaching host operating system support exists various ethernet controllers exported made configurable via management component transport protocol mctp also communicates host via pci interface linux communication host done via /dev/mei release nehalem processors usually embedded motherboard northbridge following memory controller hub mch layout newer intel architectures intel 5 series onwards included platform controller hub pch intel current terminology 2017 one several firmware sets converged security manageability engine csme prior amt version 11 csme called intel management engine bios extension intel mebx russian company positive technologies dmitry sklyarov found firmware version 11 runs minix 3 several weaknesses found may 1 2017 intel confirmed remote elevation privilege bug sa-00075 management technology every intel platform provisioned intel standard manageability active management technology small business technology nehalem 2008 kaby lake 2017 remotely exploitable security hole several ways disable without authorization could allow functions sabotaged found additional major security flaws affecting large number computers incorporating trusted execution engine txe server platform services sps firmware skylake 2015 coffee lake 2017 confirmed intel 20 november 2017 sa-00086 unlike sa-00075 bug even present amt absent provisioned disabled known unofficial methods july 2018 another set vulnerabilitites disclosed sa-00112 september 2018 yet another vulnerability published sa-00125 normally possible user disable undocumented methods discovered however methods supported intel security architecture designed prevent disabling thus possibility considered intel security vulnerability example virus could abuse make computer lose functionality typical end-user expects ability play media drm hand malicious actor could use remotely compromise system strictly speaking none known methods disables completely since required booting main cpu known methods merely make go abnormal states soon boot seems working functionality still physically connected current microprocessor continuing execute code 2016 me_cleaner project found integrity verification broken supposed detect tampered case shut pc forcibly every 30 minutes system start prevents compromised system running undetected yet allows owner fix issue flashing valid version firmware grace period project found making unauthorized changes firmware possible force abnormal error state prevented triggering shutdown even large parts firmware overwritten thus made inoperable august 2017 russian company positive technologies dmitry sklyarov published method disable via undocumented built-in mode intel confirmed contains switch enable government authorities nsa make go high-assurance platform hap mode boot mode disables functions authorized use government authorities supposed available machines produced yet turned machines sold retail market tricked activating switch.. manipulation hap bit quickly incorporated me_cleaner project late 2017 several laptop vendors announced intentions ship laptops intel disabled none two methods disable discovered far turned effective countermeasure sa-00086 vulnerability vulnerability early-loaded module essential boot main cpu ring −3 rootkit demonstrated invisible things lab q35 chipset work later q45 chipset intel implemented additional protections exploit worked remapping normally protected memory region top 16 mb ram reserved rootkit could installed regardless whether amt present enabled system chipset always contains arc coprocessor −3 designation chosen coprocessor works even system s3 state thus considered layer system management mode rootkits vulnerable q35 chipset keystroke logger me-based rootkit demonstrated patrick stewin another security evaluation vassilios ververis showed serious weaknesses gm45 chipset implementation particular criticized amt transmitting unencrypted passwords smb provisioning mode ide redirection serial lan features used also found zero touch provisioning mode ztc still enabled even amt appears disabled bios 60 euros ververis purchased go daddy certificate accepted firmware allows remote zero touch provisioning possibly unsuspecting machines broadcast hello packets would-be configuration servers may 2017 intel confirmed many computers amt unpatched critical privilege escalation vulnerability cve-2017-5689 vulnerability nicknamed silent bob silent researchers reported intel affects numerous laptops desktops servers sold dell fujitsu hewlett-packard later hewlett packard enterprise hp inc. intel lenovo possibly others researchers claimed bug affects systems made 2010 later reports claimed bug also affects systems made long ago 2008 vulnerability described giving remote attackers june 2017 platinum cybercrime group became notable exploiting serial lan sol capabilities amt perform data exfiltration stolen documents months previous bugs subsequent warnings eff security firm positive technologies claimed developed working exploit 20 november 2017 intel confirmed number serious flaws found management engine mainstream trusted execution engine tablet/mobile server platform services high end server firmware released critical firmware update essentially every intel-based computer last several years including desktops servers found vulnerable security compromised although potential routes exploitation entirely known possible patch problems operating system firmware uefi bios update motherboard required anticipated take quite time many individual manufacturers accomplish ever would many systems none known unofficial methods disable prevent exploitation vulnerability firmware update vendor required however discovered vulnerability note firmware updates fully effective either attacker access firmware region simply flash old vulnerable version exploit bug july 2018 intel announced 3 vulnerabilities cve-2018-3628 cve-2018-3629 cve-2018-3632 discovered patch csme firmware would required intel indicated would patch 3rd generation core processors earlier despite chips chipsets far back intel core 2 duo vpro intel centrino 2 vpro affected critics like electronic frontier foundation eff security expert damien zammit accused backdoor privacy concern zammit stresses full access memory without parent cpu knowledge full access tcp/ip stack send receive network packets independently operating system thus bypassing firewall intel responded saying intel put back doors products products give intel control access computing systems without explicit permission end user intel design backdoors access products recent reports claiming otherwise misinformed blatantly false intel participate efforts decrease security technology context criticism intel amd secure technology pointed nsa budget request 2013 contained sigint enabling project goal insert vulnerabilities commercial encryption systems systems … conjectured intel amd secure technology might part programme google attempting eliminate proprietary firmware servers found hurdle shortly sa-00086 patched vendors amd processor mainboards started shipping bios updates allow disabling amd secure technology subsystem similar function management engine often confused intel amt amt runs available processors vpro amt enables owners remote administration computer like turning reinstalling operating system however built intel chipsets since 2008 amt amt unprovisioned owner official documented way disable
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Computer security
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positive hack days positive hack days phdays computer security conference held every year moscow first conference held 2011 conference addresses topics zero-day attacks digital investigations cryptography cyberwarfare security person state cyberworld attendance fee required free tickets available winners special hacking contests students participated positive education program phdays aimed wide range audience hackers technical experts businessmen politicians presentations given russian english first conference held may 19 2011 reports workshops covered topics government control information security russia internet banking system safety secure connection voip protection data cloud virtualization system security keynote speaker event dmitry sklyarov conference capture flag ctf competition held among information security specialists different countries u.s. team ppp winner hacking contests one participant detected zero-day vulnerability safari windows among speakers experts kaspersky lab russian agricultural bank vimpelcom rostelecom cisco systems leta it-company positive technologies pwc 500 people attended one-day event second conference conducted may 30 31 2012 digital october center new technologies along six parallel streams presentations workshops ctf competition security-related contests held topics divided two areas technical exploiting radio noise password protection telecom security usage sqlmap business internet banking security data leakage government seeking specialists information security conference featured bruce schneier american cryptographer author applied cryptography datuk mohd noor amin impact un alexander peslyak known solar designer creator password cracking tool john ripper significant events include demonstration zero-day vulnerabilities windows xp freebsd 8.3 cracking iphone 4s contests taking control ar.drone analyzing internet banking system security young school competition young scientists research papers took place first time among conference participants representatives kaspersky lab national agency computer security tunisia cisco systems eset openwall project highload lab companies phdays 2012 gathered 2,000 people third conference held may 23 24 world trade center among main topics ics protection web application mobile application security preventing attacks banking systems cooperation government researchers information society marc van hauser heuse creator thc-hydra amap susefirewall founder hacker choice became leading speaker significant events include report scada strangelove security siemens simatic software workshop hacking atm workshop open organisation lockpickers experts nondestructive lock opening model railroad controlled real industrial systems labyrinth rooms laser field motion detectors george hotz geohot participated ctf contest member ppp first unlock iphone allowed using providers besides george hotz also 2drunk2hack contest participants hack web applications strong drink fail specialists kaspersky lab cisco systems nokia rsa iponweb qualys visited conference phdays iii saw 2,500 attendees movie preparation conference released 2013 conference took place may 21 22 2014 digital october among main topics protection ics critical infrastructure components internet banking system security internet things regulation information security industry cyberwarfare alisa shevchenko detected several zero-day vulnerabilities indusoft web studio 7.1 contest analyzing ics security significant events include contest identifying threats smart home discussion security telecommunications companies lack really smart grids power industry security-related competition participants managed withdraw money banking system developed especially competition filled vulnerabilities commonly occur real internet banking systems specialists kaspersky lab cisco systems revuln toool parameter security took part conference phdays iv drew 2,500 attendees conference held 26 27 may 2015 world trade center moscow russia conference held 17 18 may 2016 world trade center moscow russia conference held 23 24 may 2017 world trade center moscow russia conference held 15 16 may 2018 12 krasnopresnenskaya embankment moscow russia conference held 21 22 may 2019 crocus expo international exhibition center moscow russia technical reports workshops competitions discussions regulation industry business development commonly held phdays however feature conference providing special activities aimed creating open cyberpunk atmosphere conference always ends live performances popular russian rock bands 2014 cyberpunk movies played night two days conference
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Computer security
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mizar system mizar system consists formal language writing mathematical definitions proofs proof assistant able mechanically check proofs written language library formalized mathematics used proof new theorems system maintained developed mizar project formerly direction founder andrzej trybulec 2009 mizar mathematical library largest coherent body strictly formalized mathematics existence mizar project started around 1973 andrzej trybulec attempt reconstruct mathematical vernacular checked computer current goal apart continual development mizar system collaborative creation large library formally verified proofs covering core modern mathematics line influential qed manifesto currently project developed maintained research groups białystok university poland university alberta canada shinshu university japan mizar proof checker remains proprietary mizar mathematical library—the sizable body formalized mathematics verified—is licensed open-source papers related mizar system regularly appear peer-reviewed journals mathematic formalization academic community include studies logic grammar rhetoric intelligent computer mathematics interactive theorem proving journal automated reasoning journal formalized reasoning distinctive feature mizar language readability common mathematical text relies classical logic declarative style mizar articles written ordinary ascii language designed close enough mathematical vernacular mathematicians could read understand mizar articles without special training yet language enables increased level formality necessary automated proof checking proof admitted steps justified either elementary logical arguments citing previously verified proofs results higher level rigor detail customary mathematical textbooks publications thus typical mizar article four times long equivalent paper written ordinary style formalization relatively labor-intensive impossibly difficult one versed system takes one week full-time work textbook page formally verified suggests benefits reach applied fields probability theory economics mizar mathematical library mml includes theorems authors refer newly written articles approved proof checker evaluated process peer-review appropriate contribution style accepted published associated journal formalized mathematics added mml july 2012 mml included 1150 articles written 241 authors aggregate contain 10,000 formal definitions mathematical objects 52,000 theorems proved objects 180 named mathematical facts benefited formal codification examples hahn–banach theorem kőnig lemma brouwer fixed point theorem gödel completeness theorem jordan curve theorem breadth coverage led suggest mizar one leading approximations qed utopia encoding core mathematics computer verifiable form mml articles available pdf form papers journal formalized mathematics full text mml distributed mizar checker freely downloaded mizar website ongoing recent project library also made available experimental wiki form admits edits approved mizar checker mml query website implements powerful search engine contents mml among abilities retrieve mml theorems proved particular type operator mml built axioms tarski–grothendieck set theory even though semantically objects sets language allows one define use syntactical weak types example set may declared type nat internal structure conforms particular list requirements turn list serves definition natural numbers set sets conform list denoted nat implementation types seeks reflect way mathematicians formally think symbols streamline codification distributions mizar proof checker major operating systems freely available download mizar project website use proof checker free non-commercial purposes written free pascal source code available members association mizar users
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Programming language topics
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uniloc uniloc corporation patent assertion entity founded australia 1992 develops try buy software distributed via magazines preinstalled new computers uniloc technology based patent granted inventor ric richardson also principal uniloc company original patent application dated late 1992 australia granted us 1996 covers technology popularly known product activation try buy software machine locking 1993 uniloc distributed try buy versions software multiple publishers via marketing agreement ibm initial success sale thousands copies software package first aid developed cybermedia distributed front cover windows sources magazine 1994 later uniloc worked us magazine publisher ziff davis distribute unlockable versions software front cover magazines including windows magazine 1997 us subsidiary set called uniloc pc preload produce preloaded unlockable editions popular software products new pcs distribution agreements executed emachines toshiba family pc magazine also produced two months magazines featuring unlockable software uniloc pc preload cover 2000 2003 uniloc corporation set us subsidiary called uniloc usa operates rhode island southern california company currently licensing patented technology software publishers entertainment companies including sega uniloc sued 73 companies alleges violated one copy-protection patents according uniloc 25 companies settled court due abstract nature patents litigious activities uniloc deemed patent troll critics uniloc sued microsoft 2003 violating patent relating technology designed deter software piracy 2006 us district judge william smith ruled favour microsoft appeals court overturned decision saying genuine issue material fact ruled case without hearing jury april 8 2009 rhode island jury found microsoft violated patent told microsoft pay uniloc 388 million damages success uniloc filed new patent infringement suits sony america mcafee activision quark borland software aspyr media decision microsoft subsequently overturned september 29 2009 judge smith vacated jury verdict ruled favour microsoft saying jury lacked grasp issues reached finding without legally sufficient basis uniloc appealed judge decision alleging bias 2011 jury verdict reinstated microsoft us court appeals federal circuit said instead using usual 25 percent rule damage awards infringement would need recalculated july 20 2012 uniloc filed lawsuit mojang citing minecraft pocket edition infringement upon patents claiming exclusive rights method software license checking markus persson mojang stated believe minecraft infringes uniloc us patent 6,857,067 mojang ab defend lawsuit lawsuit also filed android game developers including electronic arts maker bejeweled 2 laminar research maker x-plane distinctive developments gameloft halfbrick studios madfinger games square enix
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Computer security
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security awareness security awareness knowledge attitude members organization possess regarding protection physical especially informational assets organization many organizations require formal security awareness training workers join organization periodically thereafter usually annually topics covered security awareness training include security aware means understand potential people deliberately accidentally steal damage misuse data stored within company computer systems throughout organization therefore would prudent support assets institution information physical personal trying stop happening according european network information security agency 'awareness risks available safeguards first line defence security information systems networks 'the focus security awareness consultancy achieve long term shift attitude employees towards security whilst promoting cultural behavioural change within organisation security policies viewed key enablers organisation series rules restricting efficient working business 2016 study developed method measuring security awareness specifically measured understanding circumventing security protocols disrupting intended functions systems collecting valuable information getting caught p. 38 researchers created method could distinguish experts novices people organize different security scenarios groups experts organize scenarios based centralized security themes novices organize scenarios based superficial themes
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Computer security
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palm i705 palm i705 upgrade last series palm pdas use discontinued palm.net service access world wide web palm devices featured 8mb onboard memory sd/mmc slots used motorola dragonball vz 33 mhz processor ran palm os 4.1 noted first palm.net capable device without flip antenna internal rechargeable battery though third three models manufactured palm
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Computer architecture
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atmel avr instruction set atmel avr instruction set machine language atmel avr modified harvard architecture 8-bit risc single chip microcontroller developed atmel 1996 avr one first microcontroller families use on-chip flash memory program storage 32 general-purpose 8-bit registers r0–r31 arithmetic logic operations operate registers load store instructions access ram limited number instructions operate 16-bit register pairs lower-numbered register pair holds least significant bits must even-numbered last three register pairs used pointer registers memory addressing known x r27 r26 r29 r28 z r31 r30 postincrement predecrement addressing modes supported three z also support six-bit positive displacement instructions allow immediate value limited registers r16–r31 8-bit operations register pairs r25 r24–r31 r30 16-bit operations adiw sbiw variants mul operation limited eight registers r16 r23 addition 32 general-purpose registers cpu special-purpose registers status register bits following address spaces available first 64 i/o registers accessible i/o data address space therefore two different addresses usually written 0x00 0x20 0x3f 0x5f first item i/o address second parentheses data address special-purpose cpu registers exception pc accessed i/o registers registers rampx rampy may present machines less 64 kib addressable memory typical atmega memory map may look like ramend last ram address parts lacking extended i/o ram would start 0x0060 arithmetic operations work registers r0–r31 directly ram take one clock cycle except multiplication word-wide addition adiw sbiw take two cycles ram i/o space accessed copying registers indirect access including optional postincrement predecrement constant displacement possible registers x z accesses ram takes two clock cycles moving registers i/o one cycle moving eight sixteen bit data registers constant register also one cycle reading program memory lpm takes three cycles instructions one 16-bit word long save including 16-bit 22-bit address take two words two types conditional branches jumps address skips conditional branches brxx test alu flag jump specified address skips sbxx test arbitrary bit register i/o skip next instruction test true following instructions implemented atmel avr controllers case instructions performing multiplications extended loads/jumps/calls long jumps power control optional instructions may grouped three categories higher-end processors tend capable cores memory presence one guarantee presence beginning original classic core enhancements organized following levels includes preceding less capable classic cpu cores two subsets avr1 core avr tiny confusingly attiny branded processors variety cores including avr1 attiny11 attiny28 classic attiny22 attiny26 classic+ attiny24 avrtiny attiny20 attiny40 avr1 subset popular new models introduced since 2000 omits ram except 32 registers mapped address 0–31 i/o ports addresses 32–95 stack replaced 3-level hardware stack codice_7 codice_8 instructions deleted 16-bit operations deleted codice_9 codice_10 load store addressing modes except indirect via z second successful attempt subset avr instruction set avr tiny core significant change avrtiny core omits registers r0–r15 registers also memory-mapped i/o ports 0–63 general-purpose ram beginning address 64 16-bit arithmetic operations codice_11 codice_12 omitted load/store displacement addressing modes codice_13 codice_14 predecrement postincrement addressing modes retained codice_1 instruction omitted instead program rom mapped data address space may accessed normal load instructions finally avrtiny core deletes 2-word codice_16 codice_17 instructions direct ram addressing instead uses opcode space previously assigned load/store displacement instructions new 1-word codice_16 codice_17 instructions access first 128 locations general-purpose ram addresses 0x40 0xbf codice_20 codice_21 instructions provide direct access i/o space 0 0x3f smallest cores ≤256 bytes data address space meaning ≤128 bytes ram i/o ports reserved addresses removed ≤8192 bytes 8 kib program rom 8-bit stack pointer spl support 12-bit relative jump/call instructions codice_22/codice_23 avr program counter counts 16-bit words bytes 12-bit offset sufficient address 2 bytes rom additional memory addressing capabilities present required access available resources three instructions present models corresponding hardware facility architectures avr1 named according avr-libc conventions bit assignments atmel avr uses many split fields bits contiguous instruction word load/store offset instructions extreme example 6-bit offset broken three pieces
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Computer architecture
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socket am2+ socket am2+ cpu socket immediate successor socket am2 used several amd processors athlon 64 x2 socket am2+ mid-migration socket am2 socket am3 am2+ am2 socket cpus motherboards potential operate together actual interoperability depends upon factors especially availability compatible bios software pc retailers dell provided compatible bios versions allow use socket am2+ cpus products utilizing socket am2 motherboards inspiron 531 main differences socket am2 am2+ socket processors follows technical documentation readily available earlier generations amd processor sockets am2r2 processor functional data sheet amd document number 41607 made publicly available amd confirmed am2 processors work am2+ motherboards am2+ processors work am2 motherboards however operation am2+ processors am2 motherboards limited specifications socket am2 1 ghz hypertransport 2.0 one power plane cores imc am2 processors benefit faster hypertransport 3.0 separate power planes am2+ motherboards am2 components am2+ cpus motherboards designed use ddr2 ram exclusively many manufacturers dell case inspiron 531 yet may choose release bios updates would enable compatibility result consumers unable upgrade pcs am2+ cpus despite technically possible instead would buy new motherboard upgrade processor msi simply stated am2 motherboards compatible am2+ processors amd confirmed upgrade path socket am2+ am3 pin configuration am2+ socket 940 pins mechanically different am3 socket 941 pins 4 holes fastening heatsink motherboard placed rectangle lateral lengths 48 mm 96 mm amd sockets socket am2 socket am2+ socket am3 socket am3+ socket fm2 cooling solutions therefore interchangeable motherboard manufacturers e.g asrock jetway msi released hybrid motherboards equipped am2+ socket ddr2 ddr3 memory slots boards permit use am2/am2+ processors ddr2 ram am3 processors either ddr2 ddr3 ram sole principal change am2+ am3 support ddr3 sdram am3+ modification am3 socket designed cpus use bulldozer microarchitecture
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Computer architecture
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polymorphic association polymorphic association term used discussions object-relational mapping respect problem representing relational database domain relationship one class multiple classes statically typed languages java multiple classes subclasses superclass languages duck typing ruby necessarily case java persistence hibernate chapter 5 bauer christian gavin king manning copyright 2007
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Databases
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