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joseph henry condon joseph henry 'joe condon born february 15 1935 january 2 2012 american computer scientist engineer physicist spent career bell labs son edward condon distinguished american nuclear physicist pioneer quantum mechanics participant development radar nuclear weapons world war ii part manhattan project emilie honzik condon named 19th century american physicist joseph henry condon developed interest physics electronics early age credited introduction analytical thinking anonymous instrument maker attended johns hopkins university received bs degree physics 1958 northwestern university received ph.d. physics 1963 graduate school condon joined metallurgy research division bell laboratories murray hill new jersey arrived time division split formerly physics metallurgy chemistry one executive director split physics director chemistry metallurgy another worked five years solid-state physics metals low temperatures electronic band structure metals means oscillatory diamagnetic susceptibility de haas–van alphen effect studies beryllium silver 19661968 showed magnetic domains later called 'condon domains form non-ferromagnetic metals oscillating differential magnetic susceptibility greater unity developed theory verified experimentally condon became interested electronics engineering moving physics exposed unix honeywell 516 machines early 1970s 1960s condon contributed development local area network digital telephone switching condon ken thompson promoted use c programming language switching system control programs condon acquired small pbx telephone switch handled 50 phones made necessary hardware changes thompson wrote necessary software programs pbx code rewrite c success hastened adoption c switching system software within circa 19681969 condon head department 13 owned pdp-7 computer computer loaned dennis ritchie ken thompson used create famous early computer game space travel port various features recently cancelled multics project developments directly led development unix operating system modern derivatives 1975 condon joined computer research center bell labs c programming language unix operating system created condon colleagues automated laborious error-prone task manually converting drawings fabricate circuit boards system unix circuit design system ucds enabling rapid prototyping collaboration thompson condon created chess-playing machine belle condon designed custom hardware ken designed software 1982 condon collaborated andrew ogielski create spin glass machine single-purpose computer 5-10 times faster cray-1 designed facilitate monte carlo calculations theoretical physicists determine properties class recently discovered complex magnetic materials spin glasses various random antiferromagnets thus combining interests digital systems physics condon obituary physics today called work spin glass machine classic remain accurate day despite immense increases computing power condon retired 1989 continued consult bell labs another 10 years condon died january 2 2012 joe said natural teacher drew deep understanding physics explaining problem either basic physics digital design addition unlimited curiosity extensive knowledge delightful sense humor designs said parsimonious personal interests included american indian crafts classical music theater travel wife carol rv quaker frequent volunteer fish hospitality program local charity providing shelter homeless people single mothers
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Operating systems
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accredited symbian developer accredited symbian developer asd defunct accreditation program software developers using symbian os mobile phone operating system terminated april 2011 closure symbian foundation scheme operated independently foundation behalf majinate limited also closed business foundation closed primary qualification accredited asd pass on-line multiple choice examination adhered principles symbian os curriculum curriculum reviewed annual basis ensure accreditation kept date developments symbian operating system final release curriculum made 2009 although still adhered closely asd primer learning aid published wiley symbian press imprint final version curriculum contained following major topics topic assessed marked separately examination pass required high score coverage majority topics
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Operating systems
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ios 7 ios 7 seventh major release ios mobile operating system developed apple inc. successor ios 6 announced company worldwide developers conference june 10 2013 released september 18 2013 succeeded ios 8 september 17 2014. ios 7 introduced completely redesigned user interface design credited team led apple senior vice president design jony ive new look featuring flatter icons new slide-to-unlock function new animations described ive profound enduring beauty simplicity new design implemented throughout operating system including notification center updated three tabs offering different views information notifications visible lock screen redesigned siri voice assistant offering visual indicators control center offering easy access commonly used features ios 7 also introduced airdrop wireless sharing technology carplay phone car integration automatic app updates app store reception ios 7 mixed new design language criticized critics noting implementation design changes rather actual productivity improvements citing examples animations delaying access lack icon consistency buttons hidden negative aspects user experience addition control center praised updates siri multitasking shortly release reports new design causing sickness trend explained caused animations similar effects car sickness user adoption ios 7 fast ios market share reported high 35 one day installed 200 million devices within 5 days apple claimed fastest software upgrade history ios 7 introduced apple worldwide developers conference june 10 2013 beta release made available registered developers announcement ios 7 officially released september 18 2013. ios 7.0.1 released september 20 2013 specifically iphone 5c iphone 5s update included bug fixes allow users purchase itunes content touch id fingerprint recognition scanner rather passcode ios 7.0.2 released september 26 2013 update fixed bugs could allow someone bypass lock screen passcode reintroduced greek keyboard option passcode entry ios 7.0.3 released october 23 2013 support ipad air ipad mini 2 also included support icloud keychain password generator safari web browser updated lock screen delay slide unlock text touch id use many bug fixes ios 7.0.4 released november 14 2013 bug fixes addressing facetime calls failing ios 7.0.5 released january 29 2014 fix correcting network provisioning iphone 5s iphone 5c models china ios 7.0.6 released february 21 2014 fix ssl connection verification issue ios 7.1 released march 10 2014 update included improvements touch id fingerprint technology support carplay fix home screen crash issue also brought visual updates shift caps lock keys keyboard refined icons several apple standard apps redesign aspects phone dialer shutdown screens ios 7.1.1 released april 22 2014 bug fixes ios 7.1.2 released june 30 2014 bug fixes improved ibeacon connectivity stability last version ios supported iphone 4. ios 7 introduced complete visual overhaul user interface sharper flatter icons slimmer fonts new slide-to-unlock function new control panel slides bottom screen frequently accessed settings operating system also significantly redesigned standard pre-installed apps apple jony ive apple head design commented profound enduring beauty simplicity clarity efficiency true simplicity derived much absence clutter ornamentation bringing order complexity ... ios 7 clear representation goals whole new structure coherent applied across entire system ios 7 introduced airdrop wireless sharing technology accessible share icon lets users send files local device nearby ios devices enabled control center options controlling discovery devices including contacts everyone launch airdrop available iphone 5 later fourth-generation ipad later ipad minis fifth-generation ipod touch ios 7 introduced control center menu users access swiping bottom screen providing access frequently used settings airplane mode wi-fi bluetooth disturb mode rotation lock slider adjusting screen brightness controls music playback along volume slider flashlight toggle also available icon quickly accessing camera ios 7 overhauled notification center visual functional changes three tabs today information coming day missed notifications visible phone lock screen notifications synchronized across devices users n't need dismiss notification multiple times different devices ios 7 expanded screen app switching users double-tapped home button taken current app view full-screen thumbnails recently accessed apps carplay formerly ios car released part ios 7.1 integrates selected car models offer phone interaction including music controls maps navigation car display users also talk siri send messages hands-free supports lightning-equipped iphones ios 7.1 later siri features new design assistant fades background app blurred speaking visual vocal waves appear form spinning circle device communicates apple servers siri control limited set device settings including bluetooth assistant alternatively send user directly settings menu query controlled voice otherwise displays error request ca n't processed searching internet bing became default search engine siri web resources expanded include wikipedia siri also deeply connected twitter offering full tweet search ios 7 also allowed user change siri gender new options male female voices spotlight search accessed holding dragging home screen ios 7 came new wallpapers included parallax effect icons appear moving user moves phone around producing illusion icons floating background wallpaper settings users option make custom vibrations certain types notifications turn parallax wallpaper animation effect using reduce motion setting block callers block applying across multiple devices apps including phone messages facetime home screen newly installed apps recently updated apps blue dot next user opens app first time folders updated incorporate different pages similar home screen layout allowing significant expansion folder functionality page folder contain nine apps 15 pages total allowing total 135 apps single folder app store received several significant changes ios 7 users enable automatic app updates users view history updates installed app location services enabled app store near tab recommends popular apps based user geographic location also became possible download older versions apps case new ios versions left older devices incompatible system updates allowing users maintain working copy last supported update app ios 7 introduced square photo mode camera app enabling instagram-style photos also new live filters nine different filter options change photo appearance improvements camera included ability pinch-to-zoom video recording burst mode easily taking successive photos holding shutter button causing phone take 10 frames per second iphone 5s slow-motion video option added ability shoot video high frame rate 120 frames per second edited photos app users decide start end slow-motion part photos app updated new categorization options three tabs bottom photos shared albums open different app sections featuring galleries main photos interface app displays timeline photos sorted years collections moments filters added allowing users choose several types filters add photos alongside existing options sharing pictures app updated support new airdrop functionality music app integrated apple itunes radio service station-based music service let users choose artist service generating station based similar artists songs users able skip songs search history previous songs addition able purchase songs directly itunes store playing itunes radio also feature showed songs currently trending twitter itunes radio free ad-supported users could subscribe itunes match enabled ad-free playback two years release itunes radio eventually discontinued january 2016 features moving new apple music music subscription service beats 1 radio station ios 7 safari web browser received multiple significant updates two search bars found previous iterations browser combined single smart search field tab management improved allow eight open tabs well stacking tabs top vertically opposed horizontal card view option enter private tab built app rather settings menus new track button allows user manage privacy levels apple maps features turn-by-turn walking directions design maps updated feature full-screen view interface elements search bar disappear view alongside new translucent search lower toolbars night mode automatically activates users drive night separate siri volume control available maps enabling users change relative volume siri voice feedback independently system volume n't shout loud background music weather app ios 7 received significant changes including new icon absence static weather indicator app thumbnail home screen new dynamic visual representations current weather ios 7 facetime app iphone facetime audio feature allows users call wi-fi facetime audio accessible phone app contacts app facetime app available devices running ios 7 later messages app allows users see timestamps every message sent received reception ios 7 mixed mark rogowsky forbes criticized multiple aspects new design including 3d effect home screen wallpaper writing interaction ios 7 screen background challenging best writing new overall design language operating system icons fly screen whenever unlock like kind videogame effect pointless delays access phone fraction second arguably distracting joshua topolsky verge also criticized design noting lack icon consistency different parts os well writing instead correcting issues notification panel alerts apple simply given fresh coat paint several layers sub-navigation ... nothing actually speed productivity device nielsen norman group research company wrote extensive report user-experience ios 7 summarizing report flat design hides calls action swiping around edges interfere carousels scrolling david pogue new york times however liked minimalist design ios 7 writing longer spend new os 're grateful fixing de-annoyifying display swipe upward bottom screen open control center compact visual palette controls settings functions 're likely need also praised improvements siri voice assistant writing siri much better concluded writing structure layout features represent apple best work look ios 7 — well judgment darrell etherington techcrunch focused many new features introduced praising control center incredibly useful airdrop great although noting lack interoperability ios mac time siri generally useful new multitasking features smarter multitasking screen much better conclusion wrote question ios 7 dramatic change ios many users already know love balance update packed plenty new features make using apple mobile devices easier enjoyable critics noted influence competition mobile platforms design functionality ios 7 note use concepts android windows phone similarly minimal typographic design control center equivalent similar settings toggles notification shade android similar multitasking menu webos even design weather app almost identical windows 8 htc sense sascha segan pc magazine stated apple brilliance putting pieces together marketing apple developer apis history making money developers still reign supreme—there less piracy android bigger audience design flexibility windows phone adoption rate ios 7 reported high 35 one day within five days ios 7 installed 200 million devices apple claimed fastest software upgrade history august 2014 reported 91 ios devices ran ios 7 time september 2013 pranav dixit fast company reported user complaints shared apple support forums new design ios 7 including many zoom animations multitasking opening closing apps addition slight parallax effect causing users feel sick dixit noted parallax effect could turned animations option dr. george kikano division chief family medicine uh case medical center ohio told fox news ’ validity people susceptible fox news wrote dr. kikano said new parallax function causes background phone subtly move back forth feature leads effect unlike car sickness inner ear responsible balance eyes vision things sync feel dizzy nauseous people get people n't people get used adrian kingsley-hughes zdnet wrote march 2014 iphone ipad users reported battery drain ios 7.1 update lab testing andrew cunningham ars technica found hardware models experienced minor battery depletion others experienced statistically significant changes dom esposito 9to5mac reported june 2014 new lock screen bypass method discovered ios 7 allowing access phone 5 seconds certain circumstances issue later fixed ios 7 release fake advertisements claimed update would cause devices become waterproof airdrop mechanism protecting device screen breaking dropped release apple dropped support older devices specifically iphone 3gs fourth-generation ipod touch
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trojan horse computing computing trojan horse trojan malware misleads users true intent term derived ancient greek story deceptive trojan horse led fall city troy trojans generally spread form social engineering example user duped executing e-mail attachment disguised appear suspicious e.g. routine form filled clicking fake advertisement social media anywhere else although payload anything many modern forms act backdoor contacting controller unauthorized access affected computer trojans may allow attacker access users personal information banking information passwords personal identity also delete user files infect devices connected network ransomware attacks often carried using trojan unlike computer viruses worms trojans generally attempt inject files otherwise propagate terminology occurred first time us air force report 1974 analysis vulnerability computer systems made popular ken thompson 1983 turing award acceptance lecture reflections trusting trust subtitled mentioned knew possible existence trojan horses report security multics unfortunately unable find reference however paul karger roger schell affirm cited report trojan way may require interaction malicious controller necessarily distributing trojan fulfil purpose possible involved trojans scan computers network locate trojan installed hacker control trojans take advantage security flaw older versions internet explorer google chrome use host computer anonymizer proxy effectively hide internet usage enabling controller use internet illegal purposes potentially incriminating evidence indicates infected computer ip address host computer may may show internet history sites viewed using computer proxy first generation anonymizer trojan horses tended leave tracks page view histories host computer later generations trojan tend cover tracks efficiently several versions sub7 widely circulated us europe became widely distributed examples type trojan german-speaking countries spyware used made government sometimes called govware govware typically trojan software used intercept communications target computer countries like switzerland germany legal framework governing use software examples govware trojans include swiss minipanzer megapanzer german state trojan nicknamed r2d2 german govware works exploiting security gaps unknown general public accessing smartphone data becomes encrypted via applications due popularity botnets among hackers availability advertising services permit authors violate users privacy trojans becoming common according survey conducted bitdefender january june 2009 trojan-type malware rise accounting 83 global malware detected world trojans relationship worms spread help given worms travel across internet bitdefender stated approximately 15 computers members botnet usually recruited trojan infection
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Computer security
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ibm topview topview first object-oriented multitasking windowing personal computer operating environment pc dos developed ibm announced august 1984 shipped march 1985 topview provided text-mode although also ran graphics mode operating environment allowed users run one application time pc ibm demonstrated early version product key customers making generally available around time shipped new pc computer microsoft announced windows 1.0 november 1983 international business machines ibm microsoft important partner popularizing ms-dos ibm pc notably announce support forthcoming window environment ibm determined microcomputer market needed multitasking environment released topview 1985 press speculated software start ibm plan increase control ibm pc even though nothing ibm pc proprietary including bios published world creating proprietary operating system similar ibm offered years larger computers topview also allowed ibm serve customers surprised new ibm come operating system able use hardware multitasking protected mode features new 80286 cpu dos applications still running 8086/8088 real mode even given topview virtual memory management capabilities hardware limitations still held new environment back—a base 256 kb ram room 80 kb application code data ram dos topview loaded 512-640 kb recommended load two typical application programs time maximum earlier ibm xt could installed loaded topview took back much memory consumed dos still enough satisfy industry critics topview ran real mode x86 processor could run well behaved dos programs i.e programs write directly screen used bios int 10h dos int 21h ibm assistant series productivity programs arrangement windows well behaved applications would use standard dos bios function calls access system services hardware misbehaving programs i.e programs write directly screen lotus 1-2-3 wordstar dbase iii would still run topview environment would consume entire screen object-oriented applications written using topview api topview updated make use virtual 8086 mode added intel 80386 processors allowed better virtualization initially compatibility extended features limited mainly ibm applications along third-party products like wordperfect volkswriter chicken-and-egg situation developed third-party developers reluctant add extended feature support block insert delete allow users cut/copy/paste applications see market demand dos programs however support functions allow user perform cut copy paste operations using topview pop-up menus believed ibm planned use topview force rely comply new technical specifications later versions topview released able successfully make challenging dos apps run multitasking fashion intercepting direct access system services hardware topview first introduced program information files pif files defined given dos program run multi-tasking environment notably avoid giving unnecessary resources could remain available programs topview pif files inherited extended quarterdeck desqview microsoft windows concept program information files also used digital research operating systems concurrent dos multiuser dos datapac system manager real/32 however using pifed command necessary program information got directly embedded .exe .com executable file version 1.1 introduced june 1986 added support ibm pc network ibm 3270 terminal emulation importantly support swapping non-resident programs added—onto hard disk computers high memory area machines equipped 286 cpu initially poor support dos batch files improved version 1.12 introduced april 1987 added support new ibm ps/2 series dos 3.30 operating system new ps/2 mice could also use four serial ports topview sold expectations start many potential users already satisfied cheaper less memory-intensive tsr task switchers like ready spotlight borland sidekick n't need multitasking environment topview ran graphics mode topview /g however rarely used mid-1987 ibm began shift focus away topview promoting use os/2 developers end users alike os/2 1.0 pre-emptive multitasking multithreading os allowed one real mode multiple 16-bit protected mode sessions run time pc/at based 80286 provided dos alternative announced april 1987 made available later december graphical user interface presentation manager added os/2 1.1 october 1988 1.1 could run without presentation manager well embedded system screen keyboard mouse interface required ibm officially stopped marketing final release topview version 1.12 3 july 1990 topview concept carried forward dos multitaskers notably quarterdeck desqview retained topview user interface many features plus added features support special features 80286 80386 compatible processors desqview/x released june 1992 true gui interface running dos variety similar programs topview also available including one dynamical systems called mondrian microsoft bought 1986 stated intention implementing topview api compatibility windows never happened later april 1992 ibm introduced os/2 2.0 included virtual 8086 mode full 32-bit support intel 80386 superseding even desqview similar environments os/2 2.0 priority based preemptive multitasking multithreading os including 32 levels priority time critical idle time 386 topview requires ibm pc dos versions 2.0 5.0 ms-dos 2.0 6.0 run later releases key contributors topview included david morrill father topview code-named orion glass project moved boca raton dennis mckinley tasking ross cook memory management bob hobbs topview toolkit neal whitten product manager bill gates steve ballmer gordon letwin key microsoft executives accepted invitation ibm executive estridge ibm boca raton see special demonstration topview gates disturbed windows multitasking windows used cooperative method share cpu windowing capabilities i.e overlapping windows etc topview gates witnessed topview running multiple copies microsoft basic interpreter running windows overlapping side-by-side multitasking fashion microsoft later released multitasking version ms-dos 4.0 multitasking learned meeting even though joint development agreement microsoft development topview estridge asked later told whitten whitten topview team wishes turn source code documentation topview microsoft within short time meeting estridge request granted gates gave code documentation group headed nathan myhrvold code modified according gates specifications purchased company product mondrian never released gates however gave members team key positions microsoft led joint development agreement microsoft agreement previously included dos co-develop os/2 agreement lasted 1990 done order satisfy usa vs. ibm anti-trust court case filed 1969 even though dismissed 1982 ibm mired antitrust troubles decade dismissal recover legal morass early mid-90s june 1990 ftc probe launched possible collusion microsoft ibm pc software market infoworld 1985 described topview bland plain vanilla software hogs far much memory byte also criticized topview memory usage stated find software written ibm pc topview-compatible noting low price innovative multitasking features magazine predicted software attract lot takers 1985 digital research positioned multitasking concurrent dos 4.1 gem alternative topview
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excellent sme excellent sme international project aiming establish white list small medium enterprises sme means certification system project brings emphasis web site certification since internet becoming prevailing media promotion search business opportunities partners project built three pillars excellent sme certificate obtained companies meeting basic criteria certificate issued period 1 year however credit score permanent monitoring certificate revoked prematurely holder credit score drops 6 publishing certificate holder exposes good standing business successful practices publishing possible holder web site stationery promotional materials vehicles etc observer thus instantly establish level trust would otherwise require inquiries credit rating agencies consequence selection business partner becomes easier faster cheaper risk free growing number certified companies business environment becomes transparent good enterprises exposed visible client easier task finding partner project initiated 2012 slovenia partners chamber commerce industry slovenia credit rating agency technology provider connet d.o.o serbia joined project year 2013 macedonia romania followed 2014 bulgaria joined
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Computer security
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registry open access repositories registry open access repositories roar searchable international database indexing creation location growth open access institutional repositories contents roar created eprints university southampton uk 2003 began institutional archives registry renamed registry open access repositories 2006 date 3,000 institutional cross-institutional repositories registered 2015 roar uk-based directory open access repositories opendoar considered two leading open access directories worldwide roar larger directory allows direct submissions directory opendoar controls submission materials dependent discretion staff opendoar requires open access scholarly publications whereas roar allows types materials included roar allows filtering country type repository sorting repository name roar companion registry open access repository mandates policies roarmap searchable international database policies charts growth open access mandates policies adopted universities research institutions research funders require researchers provide open access peer-reviewed research article output depositing open access repository created eprints university southampton 2003 institutional self-archiving policy registry became registry open access repository material archiving policies 2006 registry open access repositories mandatory archiving policies registry open access repository mandates policies around 2014 roarmap mandates classified terms strength effectiveness melibea october 2015 open-access mandates adopted 520 universities 75 research funders worldwide
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Databases
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ipkg ipkg itsy package management system lightweight package management system designed embedded devices resembles debian dpkg used unslung operating system linksys nslu2 optware openwrt openmoko webos gumstix ipaq qnap nas appliances elsewhere early 2017 still used synology nas appliances luneos operating system although opkg increasingly common replacement usual package management systems ipkg command-line utility allows installation new packages upgrading removal existing packages querying package repositories available packages listing already installed packages development project discontinued many projects formerly used ipkg adopted ipkg fork opkg replacement
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Operating systems
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playstation 4 system software playstation 4 system software updatable firmware operating system playstation 4 operating system orbis os based freebsd 9 native operating system playstation 4 orbis os fork freebsd version 9.0 released 12 january 2012 playstation 4 features two graphics apis low level api named gnm high level api named gnmx developers start gnmx wraps around gnm turn manages esoteric gpu details familiar way work developers used platforms like direct3d 11 another key area game programmable pixel shaders sony playstation shader language pssl introduced playstation 4 suggested playstation shader language similar hlsl standard directx 11 subtle differences could eliminated part preprocessor macros besides kernel related components components included worth mentioning cairo jquery lua mono openssl webkit pixman rendering library many open-source software although playstation 4 open console software development kit sdk based llvm clang sony chosen due conformant c c++ front-ends c++11 support compiler optimization diagnostics playstation 4 uses playstation dynamic menu graphical shell contrast xrossmediabar xmb used playstation portable playstation 3 well livearea used playstation vita playstation tv named dynamic menu options offers players context sensitive changing based player actually playstation 4 given time makes navigation simpler previous iteration dynamic menu alter little time possible users placing game disc drive actual gameplay beginning playstation 4 user interface attempts simplicity priority main place entertainment options content area prominently displayed large square icons horizontal line arranged recently used users scroll gamer newsfeed alternating brick-like formation reminiscent social media site pinterest many main objects display additional information cursor selected game may news updates advertisements downloadable content recently played games receive tiles along number mandatory items like live playstation internet browser applications content icon customization options sort would give players way mold display better suit needs augmented reality application playroom comes pre-installed playstation 4 console demonstrated e3 2013 utilizes sony playstation camera technology according sony fantastically fresh augmented reality entertainment experience created combining light bar located front dualshock 4 controller playstation camera players allowed produce small floating robot called asobi interacts players scans faces shoots fireballs playstation camera identifies player help light bar front flick touchpad dualshock 4 controller brings augmented reality bots function playroom creates illusion hundreds little bots inside controller released simply tap track pad functions like playstation vita ps4 owners view smartphone playstation vita drawing object flick anywhere augmented reality bots play remote play users operate ps4 uses playstation vita handheld game console allowing play ps4 games media small device via streaming games except exceptions require playstation move playstation camera compatible second screen used display unique content playing games support option confused split screen second screen may used show extra contents example maps alternate camera angles radar even playbooks sports games apart playstation vita mobile devices ipad android tablet also used second screen comes form official playstation app game companion apps knack quest heavy emphasis social features placed playstation 4 console loading ps4 number share-centric apps features new feature allows users check friends latest activities via landing page full pictures trophies recent events easy way find friends hand cross-chat feature dubbed party chat interesting way keep touch gives gamers ability chat users whether 're playing title ps4 sharing capabilities adds another layer console gaming ps4 owners able capture livestream gameplay simple button touch record 60 minutes latest gaming exploits quick press share button controller footage shared facebook twitter youtube also ability broadcast gameplay real time twitch ustream addition recording videos also social features community creation introduced via system updates favorite groups new section within friends app acts way quickly access people user plays feature aimed making easier faster get game session friends hand communities new hubs formed around shared interests like games activities play styles also exist smaller social features ps4 ability message friend request watch gameplay live playstation 4 console function without internet connection provide functionality connected internet example updates system software may downloaded internet users may play online internet properly connected online play main pillar playstation 4 playstation plus subscription required play majority ps4 titles online unlike playstation 3 titles according sony developing many new ways play connect ps4 requires large investment resources result sony claim keep service free maintain quality time considering cost thus decided would better charge fee order continue offer good service web browser included playstation 4 console based open source webkit layout engine unlike playstation 3 uses netfront browser using modern webkit core safari apple ps4 web browser receives high score html5 compliance testing however support adobe flash means websites require flash might display properly function intended also pdf format supported however one clear advantage gamers able cut gaming browsing back loss gameplay due multitasking feature web browser additionally ps4 web browser limited support usb keyboards seem support usb mice furthermore internet connection enabled playstation 4 allows users access variety playstation network psn services including playstation store playstation plus subscription service users may download buy games contents services also gamers able play selection ps3 titles via internet-based playstation gaming service playstation 4 supports playing 2d 3d blu-rays dvds. previously system software update required standard new consoles instead console needs go online activate player first time used system support audio cds internally year console launch sony partnered spotify bring music streaming service playstation 4 well predecessor february 2015 including ability stream music background game application plus ability control music playback via smartphone computers etc available free premium subscribers spotify sony later added blu-ray 3d support console via system update users also use media player application enjoy videos photos music saved usb storage devices media servers ps4 may serve good portable device video enjoyment addition game playing following multimedia file formats supported although according playstation support website ps4 could play mp4 videos support mp4 files encoded h.264/mpeg-4 avc high profile aac-lc playstation 4 backward compatible games previous playstation consoles launch though playstation 4 users play playstation 3 games directly 2014 playstation cloud-based streaming service allowed streaming selected ps3 games december 2015 sony added playstation 2 backward compatibility republished ps2 games dark cloud grand theft auto iii ps4 via playstation store americas europe supported ps2 games run via software emulation upscaled high definition ps4 systems instead remastered one updated access various ps4 features including trophies share play broadcasting remote play second-screen features however original ps2 game discs ps2 classics re-released ps3 compatible ps4 system arabic chinese simplified chinese traditional czech danish dutch english united kingdom english united states french canada french france finnish german greek hungarian indonesian italian japanese korean norwegian polish portuguese brazil portuguese portugal russian romanian spanish latin america spanish spain swedish thai turkish vietnamese initial version system software playstation 4 1.01 pre-installed original consoles support remote play second screen experiences added version 1.50 launched day playstation 4 console released north america november 15 2013 features accessible playstation vita console using ps4 link application second screen functionality also accessible smartphones tablets playstation mobile app also able record share video clips well broadcasting gameplay twitch.tv ustream supports blu-ray dvd-video playback version 1.60 released february 4 2014 improving dvd playback version 1.60 also adds support pulse elite wireless headsets version 1.70 released april 30 2014 adds number new features addition rich video editor called sharefactory offers users tools combine edit personalize captured video clips update also adds abilities share video clips screenshots streaming copy video clips screenshots usb storage version 1.75 released july 29 2014 adding support playback blu-ray 3d also improves sound quality 1.5-speed playback blu-ray dvd video version 1.76 released september 2 2014 came minor changes last update version 2.0 released october 28 2014 version 2.00 major upgrade playstation 4 system software among features introduced share play allows playstation plus users invite online friend join play session via streaming even copy game users pass control game entirely remote user partake cooperative multiplayer physically present version also adds youtube app ability upload video clips youtube users play music stored usb storage devices also support custom themes ability change background color users set themes home screens function screens user version version 2.50 released march 26 2015 adding suspend/resume feature allow players jump games ps button games suspended low-power rest mode instead closing completely version also allows console hard drive backed restored usb flash drive september 30 2015 sony released ps4 update 3.00 introduced entirely new features user-interface enhancements among new features ability share videos directly twitter dedicated playstation plus section tweaks interface streaming youtube improvements social features messages group creation ability save screenshots pngs increase online storage capacity 1 gb 10 gb also introduced playstation plus members sony states update create new ways connect friends players around world expanding social capabilities system even april 6 2016 sony released ps4 update 3.50 would enable ps4 use remote play functionality windows macos formerly named os x vg247 reported update allow remote play functionality computers running windows 8.1 windows 10 os x yosemite os x el capitan furthermore article explains remote play support resolution options 360p 540p 720p frame rate options 30 fps 60 fps one dualshock 4 controller connected via computer usb port september 13 2016 sony released ps4 update 4.00 added high dynamic range hdr home screen folder support 1080p streaming tweaks menus game info screens greater overview streamlined interfaces march 9 2017 sony released next major firmware update version 4.50 update includes support installing applications external hard drives custom wallpapers refined quick menu simplified notifications list custom status updates new 3d blu-ray support playstation vr includes support preloading game patches however developer make use first game take advantage feature littlebigplanet 3 october 3 2017 sony released ps4 update 5.00 overhauling master/sub-account system update allows customization accounts family members roles applying parental controls account groups system replaced new friends management system along support 5.1 7.1 surround sound configurations playstation vr new tournament bracket viewer made along tweaks broadcasting 1080p streaming 60 frames per second twitch possible changes ps message notifications quick menu lastly introduces localization czech greek hungarian indonesian romanian thai vietnamese languages 5.50 released march 8 2018 includes playtime restrictions child accounts ability hide applications library custom wallpapers via usb supersampling mode ps4 pro ability delete notifications september 13 2018 sony released ps4 update 6.00 major feature added ability use remote play ios devices minor improvements may 10 2019 sony interactive entertainment added ability remove purchased games download list playstation store delete games profile gaming platforms sony gaming platforms generation gaming platforms seventh generation
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Operating systems
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tim teitelbaum ray tim teitelbaum born april 12 1943 united states american computer scientist known early work integrated development environments ides syntax-directed editing incremental computation educator faculty member cornell university computer science department since 1973 recognized large-scale teaching introductory programming mentoring highly successful graduate students businessman known co-founded grammatech inc. sole ceo since 1988 teitelbaum educated massachusetts institute technology carnegie mellon university 1978 teitelbaum created cornell program synthesizer one seminal systems demonstrated power tightly integrating collection program development tools deeply knowledgeable programming language semantics one unified framework 45 lectures demonstrations early ide 1979-82 well credo 1981 paper co-authored thomas reps asserted programs text hierarchical compositions computational structures edited executed debugged environment consistently acknowledges reinforces viewpoint motivated importance immediate feedback interactive systems ides teitelbaum ’ research 1980s 1990s focused problem incremental computation given program p written language l result executing p input x one efficiently determine result running p input x ’ difference x x ’ small increment x ’ -x body work graduate students teitelbaum investigated problem range languages l included attribute grammars sql first-order functional languages lambda calculus addition incremental evaluation methods work also included program transformation methods i.e. automatic derivation p incremental program p ’ executing p ’ previous result p x increment x ’ -x auxiliary information retained previous executions efficiently performs computation executing p input x ’ teitelbaum recent work aimed design implementation tools assist making software safer secure techniques include static program analysis dynamic program analysis source code machine code teitelbaum co-recipient association computing machinery sigsoft retrospective impact paper award 2010 1984 paper co-authored thomas reps synthesizer generator
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Programming language topics
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2 gb limit 2 gb limit refers physical memory barrier process running 32-bit operating system use maximum 2 gb memory problem mainly affects 32-bit versions operating systems like microsoft windows linux although variants latter overcome barrier also found servers like ftp servers embedded systems like xbox use physical address extension pae help overcome barrier linux freebsd unix-likes support pae long hardware windows needs boot option enabled manually known 4-gigabyte tuning 4gt /3gb switch enabled executables large address aware flag set increase memory limit 3gb 32-bit processes 64-bit windows also limited 2gb however use large address aware flag well except n't require /3gb switch increases limit 4gb could also refer maximum partition size fat16 file system versions windows prior xp
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Computer file systems
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dymola dymola commercial modeling simulation environment based open modelica modeling language large complex systems composed component models mathematical equations describe dynamic behavior system developed european company dassault systèmes dymola available standalone product integrated 3dexperience part catia dymola 2020 supports version 3.4 modelica language version 3.2.3 modelica standard library well versions 1.0 2.0 functional mock-up interface fmi dymola initially designed 1978 hilding elmqvist phd thesis lund institute technology later part lund university first version dymola based dynamic modeling language also called dymola implemented simula 67 later re-implemented pascal c++ 1992 elmqvist created swedish company dynasim ab continue development dymola 2006 dassault systèmes acquired dynasim ab started integrate dymola catia 1996 elmqvist initiated modelica design effort goal develop object-oriented language modeling technical systems reuse exchange dynamic system models standardized format modelica based dymola language experience modeling languages taken account september 1997 version 1.0 modelica specification released basis prototype implementation within dymola year 2000 non-profit modelica association formed manage continually evolving modelica language development free modelica standard library since 2002 modelica language supported dymola dymola multi-engineering capabilities mean models consist components many engineering domains using modelica language sub-systems represented interconnected components lowest level dynamic behavior described mathematical equations algorithms connections components form additional equations dymola processes complete system equations order generate efficient simulation code domain-specific knowledge represented modelica libraries containing components mechanical electrical control thermal pneumatic hydraulic power train thermodynamics vehicle dynamics air conditioning etc commercial libraries dymola supports information hiding encryption typical application areas facilitated modelica libraries include automotive applications fall three main categories engine drive train modeled using engines powertrain libraries flexibility open modelica language particularly suitable modeling hybrid alternative drive trains using battery brushless dc drives electrified powertrains libraries modal bodies flexible shafts available flexible bodies library engine battery cooling supported cooling library combined hvac library human comfort library adds models occupant comfort complete vehicle thermal modeling controller components available modelica standard library hierarchically structured open-source modelica models offer unprecedented flexibility multiple vehicle configurations reusing common components multitude libraries offer capacity model complex thermo-fluid systems aircraft ranging fuel systems environmental control human comfort library provides additional models occupant comfort cabin thermal modeling flight dynamics library enables rapid modeling simulation analysis flight dynamic characteristics wide range aircraft uavs actuators flight control subsystems use brushless dc drives electrified powertrains libraries flexible beams modal bodies finite element models managed flexible bodies library ever stringent requirements environmental impact drive trend towards detailed modeling physics control systems heat ventilation air conditioning hvac library allows minimize building hvac operating costs selecting correct system control strategy avoid costly hvac system design errors early building design process human comfort library provides integrated approach simulate thermal comfort within occupied building vehicle thermo-fluid system typically modeled thermalsystem library industrial process simulation library focused paper pulp industries kinds industrial equipment modeled using mechanical libraries modelica standard library including 3d multi-body systems options flexible beams modal bodies originating finite element model actuators control systems modeled battery brushless dc drives electrified powertrains libraries thermal properties industrial machinery easily modeled cooling library addition libraries available dymola product portfolio several libraries developed third parties claytex modelon ab tlk-thermo xrg simulation additional free commercial libraries available modelica association homepage model calibration option based process measured data real device used tune parameters simulation results good agreement measured data design optimization option used tune parameters device controller improve system dynamics multiple criteria multiple cases model management includes support encryption models version control dymola utilities checking testing comparing models also included support common version management tools cvs svn git steps system development dimensioning detailed design implementation important access c code image model run hardware loop rapid prototyping simulations build simulators validation training purposes several options available achieve activities dymola supports import export according functional mockup interface fmi appropriate options exported code generated export without run-time license source code exported functional mockup units used several simulation platforms
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Programming language topics
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bundle macos nextstep openstep gnustep lineal descendants macos ios bundle file directory defined structure file extension allowing related files grouped together conceptually single item examples bundles contain executable code include applications frameworks plugins kind bundle usually contains one file representing executable code files represent resources nibs templates images sounds media systems microsoft windows resources usually included directly executable file compile time older macintoshes similar technique used additional metadata added file resource fork similar concept application directories used risc os rox desktop examples bundles contain executable code include document packages iwork documents media libraries iphoto library bundles programmatically accessed codice_1 class cocoa nextstep gnustep foundation frameworks codice_2 core foundation uniform type identifier uti apple bundle codice_3 application bundles directory hierarchies top-level directory name ends codice_4 extension application bundle first directory bundle underneath top-level directory usually named codice_5 within codice_5 usually another directory called codice_7 macs using application name gnustep contains application executable code within codice_5 folder usually also directory called codice_9 contains resources application among things codice_9 folder contains localized versions application nib files common subdirectories include codice_11 codice_12 codice_13 codice_12 directory contains frameworks used application used even another version framework exists system codice_13 directory contains frameworks used application contains applications used newer version exist elsewhere system codice_11 contains extensible code used application default finder displays application bundles also referred packages opaque files underlying structure contents bundle shown show package contents context menu item macos frameworks also stored bundles top-level directory framework bundle name name framework followed extension codice_17 top-level directory codice_18 directory subdirectories one versions framework subdirectory containing dynamic library code framework file whose name name framework possibly codice_19 folder containing header files framework subfolders codice_9 codice_18 directory also contains symbolic link codice_22 directory current version framework top-level directory symbolic links contents codice_23 finder displays framework bundles directories rather opaque files loadable bundles bundles contain code loaded runtime loadable bundles usually extension codice_24 often used plug-ins macos way load bundles even applications n't support allowing third party hacks popular applications safari apple mail default finder displays loadable bundles also referred packages opaque files underlying structure contents bundle shown show package contents context menu item many third-party macos applications utilize custom bundle format e.g candybar codice_25 aperture codice_26 vmware fusion codice_27 etc. .lproj file bundle contains localization files macos software typically contains .nib files given language along string files images need example readme license files localized files used install makers customize install packages also included application bundle
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Operating systems
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centre cybersecurity amp cybercrime investigation university college dublin centre cybersecurity cybercrime investigation ucd cci centre research education cybersecurity cybercrime digital forensic science dublin ireland ucd centre cybersecurity cybercrime investigation established early 2000s developed collaborative relationships law enforcement industry across world centre cybersecurity cybercrime investigation widely regarded europe leading centre research education cybersecurity cybercrime digital forensics ucd cci trains specialist officers irish national police service garda síochána irish military personnel defence forces well international law enforcement agencies interpol europol authorities 40 countries cci also runs educational qualifications training industry sector multinational corporations memorandum understanding centre cybersecurity cybercrime investigation ucd national cyber security centre ncsc dccae irish government computer emergency response team ucd cci network formal relationships garda síochána irish defence forces interpol europol visa inc. irish banking federation well collaborations united nations office drugs crime unodc organization security co-operation europe osce european anti-fraud office olaf microsoft citibank ebay director ucd centre cybersecurity cybercrime investigation professor joe carthy bsc. phd
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Computer security
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wdc 65c134 western design center wdc w65c134s microcontroller complete fully static 8-bit computer fabricated single chip using low power cmos process w65c134s complements established growing line 65xx products wide range microcomputer applications w65c134s developed hi-rel applications minimum power required w65c134s consists w65c02s static central processing unit cpu 4096 bytes read memory rom 192 bytes random access memory ram two 16 bit timers low power serial interface bus sib configured token passing local area network universal asynchronous receiver transmitter uart baud rate timer one 16-bit monitor watch-dog timer restart interrupt twenty-two priority encoded interrupts ice interface real-time clock features including time day tod clock bus control register bcr external memory bus control interface circuitry peripheral devices many low power features innovative architecture demonstrated high performance w65c02s cpu well instruction simplicity result system cost-effectiveness wide range computational power features make w65c134s leading candidate hi-rel microcomputer applications product description assumes reader familiar w65c02s cpu hardware programming capabilities refer w65c02s data sheet additional information
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Computer architecture
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palmtop pc palmtop pc approximately pocket calculator-sized battery-powered computer compatible ibm personal computer horizontal clamshell design integrated keyboard display could used like subnotebook light enough comfortably used handheld well palmtop pcs small enough stored user shirt jacket pocket palmtop pcs distinguish palmtop computers using mostly ibm-compatible pc architecture bios well intel-compatible x86 processor devices dos-based dos stored rom many palmtop pcs came number pda office applications pre-installed rom could also run generic off-the-shelf pc software little modifications could also run operating systems geos windows 1.0-3.0 real mode minix 2.0 palmtop pcs based static hardware design low power consumption instant-on/off without need reboot depending model battery could power device several hours several days running week year standby mode combined instant-on/off feature battery would typically last week several months practical use pda first palmtop pc dip pocket pc aka atari portfolio 1989 palmtop pcs include touch-screen computers may also counted category clamshell design now-discontinued ultra-mobile pcs umpc seen successors class example
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Computer architecture
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wing computing wing pronounced win gee application programming interface designed provide faster graphics performance windows 3.x operating environments initially positioned way help game developers easily port dos games microsoft windows although quickly discontinued favor directx wing fixed two problems first problem wing fixed windows 3.x support creating device contexts dcs based device independent bitmaps actual display devices one major limitation gdi dcs write-only data written could retrieved second problem gdi drawing implemented windows 3.x video drivers included drawing bitmaps obviously performance routines varied across drivers alex st. john one creators directx said 2000 interview microsoft announced wing 1994 game developers conference demonstrating port id software doom wing shipped september 21 1994 wing interesting still fundamentally based drawing bitmaps memory outputting frames drawing done result wing deprecated directx built however windows nt 3.5 windows 95 introduced createdibsection provide support creating dcs based dibs video drivers also eventually improved wing introduced new type dc called wingdc allowed programmers read write directly using device-independent bitmaps dibs wingdib.drv driver effectively gave programmers ability windows 'd without hardware access limitations dos years programmers could write dibs wingdc yet would still access individual bits image data meant fast graphics algorithms could written allow fast scrolling overdraw dirty rectangles double buffering animation techniques wing also provided much better performance blitting graphics data physical graphics device memory since wing used dib format possible mix original gdi api calls wing calls wing would also perform graphics hardware/driver profiling test first execution program order determine best way draw dibs test showed window full red curved lines sections would wobble performance tested wing determined fastest calls cause graphics corruption profile would saved test would need performed wing out-of-the-box support i.e separate api win32 dropped windows 98 second edition integrated directx 6 absolutely nothing pass win32 apis wrapping including createdibsection wing dlls sometimes distributed application point merely became matter copying files wing.dll wing32.dll wingde.dll wingdib.drv wngpal.wnd system32 directory 32 bit windows syswow64 directory 64 bit windows regain system-wide support
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Operating systems
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nokia n86 8mp nokia n86 8mp high-end smartphone announced 17 february 2009 released may 2009 runs symbian os 9.3 s60 3rd edition fp2 part nseries shares similar design features n97 one main selling points carl zeiss photography features nokia first camera phone 8 megapixel sensor although late compared manufacturers features multiple aperture settings mechanical shutter uncommon features standards camera phones carl zeiss lens wide angle view 28 mm equivalent also auto focus dual led flash 3rd generation dual-leds af assist light video capture resolution 640 × 480 pixels vga 30 frames per second n86 continuous form factor nokia n95 n85 dual-sliding form factor whilst adding toughened glass front cover metal detailing keypad making look feel premium 2.6-inch amoled display fast 434 mhz processor 8 gb internal memory also kickback stand n85 possible use small standalone screen possible configure opening stand launch applications video player also supports n-gage gaming platform n86 8mp regarded spiritual successor n95 8gb due feature set sliding form factor commercial failure n96 regard successor n82 due camera n86 8mp 3.5g 3.75g 3gpp device dual-band hsdpa support quad-band gsm wi-fi a-gps receiver links location-based services via nokia maps photographs automatically geo-tagged also built-in digital compass fm radio also fm transmitter rated give 6 hours talktime 25 hours music playback 11 days standby full charge optional dvb-h nokia mobile tv receiver su-33w possible watch television screen phone ovi maps 3.03 free navigation released 17 march 2010 nokia n86 new version available via sw update application file size 8.24 mb n86 e72 e55 e52 6730 6710 s60 3rd edition feature pack 2 nokia symbian^1 s60 5th edition devices get experience beta-testing free navigation 6 july 2009 nokia n86 8mp received big firmware upgrade v11.043 brought official ovi store compatibility ovi web site shortcut option download dedicated client camera tweaks usual early firmware bug fixes improvements 30 september 2009 nokia n86 8mp received v20 firmware upgrade full week ahead schedule 8 mb large air ota update significant changes improved still image video quality close-up focus face detection indicated yellow square red-eye removal added new focus point indication shows scene camera focusing 11 january 2010 nokia n86 8mp got minor update v21 firmware version 21.006 replaced v20.115 maintenance release improving performance fixing number minor bugs 15 april 2010 version 30.009 firmware mainly features latest ovi maps client available via nokia software update 142 mb air 5085 kb includes latest ovi maps 3.03 free navigation sharing location via facebook realplayer interface tweaked d-pad problem playing videos usual minor fixes improvements 20 may 2010 includes latest ovi maps 3.04 new version adds formal support wifi positioning method part overhaul positioning functionality plus significant performance improvements search zooming map panning number consumer-friendly ui tweaks addition qype information places database nokia n87 successor n86 leaked internet full specifications december 2009 early 2010 however never released instead touchscreen nokia n8 introduced november 2010 prototype n87 appeared ebay shows running probably symbian^3 listing removed time seller nokia would never release another high-end non-touchscreen device n86 8mp
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Operating systems
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pry software pry interactive shell ruby programming language notable smalltalk-inspired ability start repl within running program lets programmers debug modify current state system pry exposes introspective capabilities using filesystem metaphor example codice_1 command start interacting particular object uses codice_2 list methods variables possible start pry point inside running program due reflective nature ruby lets programmer inspect program change current state correct source code without restarting process number third party plugins available pry add tighter integration ruby projects enhance abilities pry make pry available remote connection
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Programming language topics
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forcepoint forcepoint previously known websense raytheon|websense austin-based company owned u.s. defense contractor raytheon private equity firm vista equity partners develops markets cybersecurity software prevent employees viewing inappropriate malicious content leaking confidential data also sells firewall cloud access cross-domain security products forcepoint founded 1994 reseller called netpartners renamed websense 1999 went public following year vista equity partners acquired websense 2013 906 million taking public market raytheon acquired 80 interest websense april 2015 1.9 billion afterwards websense acquired network security vendor stonesoft intel renamed combined company forcepoint websense founded 1994 phil trubey dot-com boom name netpartners company began reseller network security products developed software controlling internet use employees 1998 netpartners raised 6 million venture capital funding 6 million annual revenue later year investors pushed trubey ceo position appointed john carrington replacement 1999 netpartners renamed websense following year websense raised 65.7 million initial public offering 2006 former mcafee ceo gene hodges succeeded carrington websense ceo year websense acquired fingerprint security company called portauthority 90 million followed 400 million acquisition email security vendor surfcontrol 2007 2009 websense acquired defensio spam malware company focused social media undisclosed sum 2009 websense 1,400 employees offices england china australia israel two years later facebook deployed websense check every link users shared site 2013 websense became private company vista equity partners acquired 906 million websense headquarters moved san diego year austin texas 2014 raytheon acquired 80 interest websense april 2015 1.9 billion followed 389 million purchase two companies stonesoft sidewinder october 2015 intel stonesoft network security product previously known mcafee next-generation firewall sidewinder firewall previously known mcafee firewall enterprise january 2016 three companies combined rebranded forcepoint new company also included raytheon cyber products business time forcepoint 2,000 employees one-third customers departments federal government united states forcepoint became smallest five major businesses owned raytheon highest profit margins following year forcepoint began shuffling executives re-organization effort included layoffs company divided four business units cloud security network security data insider threat security global governments february 2017 forcepoint announced acquisition cloud-based access broker casb security product imperva called skyfence undisclosed sum april 2016 matthew moynahan appointed ceo forcepoint august 2017 forcepoint acquired user entity behavior analytics company redowl undisclosed amount company products used block certain websites portions website inspect network traffic filter e-mails control sensitive files accessed forcepoint products also used prevent employees accessing websites deemed inappropriate workplace viewing employer example employers may prevent employees viewing pornographic content work material sex education religion dating politics forcepoint also develops markets firewall products based part technology acquired mcafee former stonesoft business intel security sidewinder product. ref name= http //www.channelweb.co.uk 2017 /ref company develops markets cloud access security broker casb products using technology acquired previously imperva skyfence product also sells analytics software detect insider data leaks several cross domain security products using forcepoint products employees internet browsers usually modified direct traffic proxy server server hosts local copies frequently-visited websites order improve download speed software also checks every url employee visits databases websites identified malware prohibited subject-matter employee url history analyzed identify risky behaviors 1997 three years forcepoint founded company published version 3 software version 3.0 introduced software first graphical web-based administrative user interface time forcepoint software used prevent employees viewing certain types content work 2006 features added detect employees attempting visit websites suspected hosting malicious code 2007 websense introduced product control content user see social media websites endpoint security product website reputation ranker small business version additionally product added websense suite identifies sensitive files un-secure locations corporate network looks records files transmitted websense introduced first appliance product 2009 following year products consolidated triton software became responsible increasingly large portions company revenue february 2012 forcepoint released cloud-based suite security products smartphones tablets laptops usb drives mobile devices upgrades suite 2012 added ability identify confidential information image file three new products revisions introduced 2016 focused security risks caused employees forcepoint policy selling governments isps engage internet censorship however criticized perceived link censorship free speech dissemination knowledge 2009 discovered yemeni government using forcepoint products monitor public internet use block tools allow citizens hide internet use government software alkasir created circumvent forcepoint responded cutting country access forcepoint database updates 2011 forcepoint said would join global network initiative focused privacy internet freedom left initiative 2014 2002 study jama found forcepoint best-performing web-filtering products terms blocking pornography allowing health information contrast 2005 report rhode island branch american civil liberties union said forcepoint blunt instrument public libraries equipped forcepoint people ages still denied access wide range legitimate material 2006 report brennan center justice found forcepoint often blocked websites discussed pornography actually feature pornography forcepoint software also blocked furniture website called the-strippers.com pornographic instead website furniture refinisher author study 0-15 percent sites blocked forcepoint viewable user 10 percent objectionable websites let rather blocked according blogger jillian york forcepoint blocks pages contain pornographic links anywhere content even comments section said malicious attacker could get whole site blocked time simple procedure leaving dangerous malicious pornographic links blog comments approximately 15 minutes 2009 forcepoint classified router company cisco website 'hack sites due one cisco ip addresses named hacking website ip address reviewed deemed threat
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Computer security
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assuresign assuresign electronic signature software solution deployed software service saas application installed customer premises documents signed using computer internet connection assuresign electronic signature technology first use patent-pending biometric handwritten mouse-based signatures assuresign documentnow documenttrak api tools enable users integrate existing environments assuresign maintains partner program includes integration partners resellers available via microsoft dynamics marketplace salesforce.com appexchange assuresign also integrated third party applications including microsoft sharepoint oracle duck creek technologies insurance applications assuresign electronic signature technology developed 2006 offering third party verification inc. 3pv assuresign llc formed separate company 2008 david brinkman dale combs assuresign 3pv consistently ranked orlando sentinel top 100 companies working families
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Computer security
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union mount computer operating systems union mounting way combining multiple directories one appears contain combined contents union mounting supported linux bsd several successors plan 9 similar subtly different behavior example application union mounting consider need update information contained cd-rom dvd cd-rom writable one overlay cd mount point writable directory union mount updating files union directory cause end writable directory giving illusion cd-rom contents updated plan 9 operating system bell labs mid-1980s onward union mounting central concept replacing several older unix conventions union directories example several directories containing executables unioned together single directory replace variable command lookup shell plan 9 union semantics greatly simplified compared implementations posix-style operating systems union two directories simply concatenation contents directory listing union may display duplicate names also effort made recursively merge subdirectories leading extremely simple implementation directories unioned controllable order union directory denotes file called first constituent directory contains file unix/posix implementations unions different requirements plan 9 implementation due constraints traditional unix file system behavior greatly complicates implementation often leads compromises problems union mounting unix-like operating systems encounters include early attempts add unioning unix filesystems included 3-d filesystem bell labs translucent file service sunos sun microsystems 1988 implementation union mounting added bsd version unix version 4.4 1994 taking inspiration earlier attempts plan 9 stackable file systems spring sun 1994 4.4bsd implements stack-of-directories approach outlined like plan 9 operations traverse stack top-down resolve names unlike plan 9 bsd union mounts recursive contents subdirectories appear merged union directory also unlike plan 9 version layers except top read-only modifying files union causes contents first copied top layer stack modifications applied deletion files implemented writing special type file called whiteout top directory effect marking file name non-existent hiding files name lower layers stack whiteouts require support underlying file system union mounting implemented linux 0.99 1993 initial implementation called inheriting file system abandoned developer complexity next major implementation unionfs grew fist project stony brook university attempt replace unionfs aufs released 2006 followed 2009 overlayfs 2014 last union mount implementation added standard linux kernel source code similarly glusterfs offers possibility mount different filesystems distributed across network rather located machine
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Computer file systems
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anatoly kucherena anatoly grigorievich kucherena born 23 august 1960 russian attorney public figure doctor law professor mid-2013 kucherena represented former nsa contractor edward snowden interests russian federation kucherena continues represent snowden pro bono occasional basis 2013 according izvestia known person spoke favour banning anonymizer software advocating prosecution development distribution usage including malware software category view contradicts terminology used industry june 2014 american film director oliver stone acquired rights screen adaptation kucherena novel time octopus story fictional american whistleblower joshua kold threatened government waiting decision request russian asylum cold spends three weeks transit area moscow airport stone said anatoly written 'grand inquisitor'-style russian novel weighing soul fictional whistleblower gravity 1984 tyranny achieved global proportions book first psychological-political thriller trilogy released 3 march 2015 russian 29 january 2017 english moscow times reported kucherena said snowden received copy book liked april 2015 wikileaks revealed oliver stone paid 1 million movie rights kucherena novel different times kucherena also represented
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Computer security
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unikernel unikernel specialised single address space machine image constructed using library operating systems developer selects modular stack minimal set libraries correspond os constructs required application run libraries compiled application configuration code build sealed fixed-purpose images unikernels run directly hypervisor hardware without intervening os linux windows first systems exokernel nemesis late 1990s library operating system protection boundaries pushed lowest hardware layers resulting library os architecture several advantages disadvantages compared conventional os designs one advantages since single address space need repeated privilege transitions move data user space kernel space therefore library os provide improved performance allowing direct access hardware without transition user mode kernel mode traditional kernel transition consists single trap instruction context switch performance gains may realised elimination need copy data user space kernel space although also possible zero-copy device drivers traditional operating systems disadvantage separation trying run multiple applications side side library os strong resource isolation become complex addition device drivers required specific hardware library os runs since hardware rapidly changing creates burden regularly rewriting drivers remain date os virtualization overcome drawbacks commodity hardware modern hypervisor provides virtual machines cpu time strongly isolated virtual devices library os running virtual machine needs implement drivers stable virtual hardware devices depend hypervisor drive real physical hardware however protocol libraries still needed replace services traditional operating system creating protocol libraries bulk work lies implementing modern library os additionally reliance hypervisor may reintroduce performance overheads switching unikernel hypervisor passing data hypervisor virtual devices reducing amount code deployed unikernels necessarily reduce likely attack surface therefore improved security properties unikernels shown around 4 size equivalent code bases using traditional os due nature construction possible perform whole-system optimisation across device drivers application logic thus improving specialisation unikernels regularly shown boot extremely quickly time respond incoming requests requests time-out unikernels lend creating systems follow service-oriented microservices software architectures high degree specialisation means unikernels unsuitable kind general purpose multi-user computing traditional operating systems used adding additional functionality altering compiled unikernel generally possible instead approach compile deploy new unikernel desired changes number new approaches constructing unikernels varying degrees maturity
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Computer architecture
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cooperative cyber defence centre excellence nato ccd coe officially nato cooperative cyber defence centre excellence nato küberkaitsekoostöö keskus one nato centres excellence located tallinn estonia centre established 14 may 2008 received full accreditation nato attained status international military organisation 28 october 2008 nato cooperative cyber defence centre excellence international military organisation mission enhance capability cooperation information sharing among nato member nations partners cyber defence virtue education research development lessons learned consultation 2003 prior country official accession nato estonia proposed creation centre excellence 2006 riga summit listed possible cyber attacks among asymmetric threats common security acknowledged need programs protect information systems long term cyber attacks estonia 2007 highlighted first time potential vulnerability nato countries institutions societies even nato disruption penetration information communications systems estonia proposals nato cyber excellence center received strong support alliance secretary-general jaap de hoop scheffer nato completed assessment situation partly light estonia experience april 2007 approved nato policy cyber defence january 2008 nato summit communiqué bucharest april announced nato readiness provide capability assist allied nations upon request counter cyber attack august 30 2018 colonel jaak tarien replaced merle maigre director organisation cyber defence center tallinn one 21 accredited centres excellence coes training technically sophisticated aspects nato operations funded nationally multi-nationally centers closely linked allied command transformation promote alliance-approved transformation goals main agenda facility centre also responsibilities include currently 22 sponsoring nations joined centre addition centre three contributing participants nato ccd coe founding nations estonia germany italy latvia lithuania slovakia spain hungary poland united states netherlands joined following years 2014 france united kingdom czech republic austria first non-nato country joined centre november 2015 finland greece turkey joined june 2019 bulgaria denmark norway romania joined membership nato ccd coe open nato nations nato ccd coe also establish cooperative relations non-nato nations universities research institutions businesses contributing participants
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Computer security
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big ball mud big ball mud software system lacks perceivable architecture although undesirable software engineering point view systems common practice due business pressures developer turnover code entropy type design anti-pattern term popularized brian foote joseph yoder 1997 paper name defines term foote yoder credited brian marick originator 'big ball mud term sort architecture programmers control big ball mud project strongly encouraged study understand accomplishes use loose basis formal set requirements well-designed system could replace technology shifts client-server web-based file-based database-based may provide good reasons start scratch discussion lisp programming language term big ball mud used differently case describe malleability lisp system lisp generally possible result confluence features lisp extraordinarily flexible even extent language implementation may completely rewritten runtime i.e reflective metaprogramming result lisp systems becoming muddy time due fluidity ease may extended evolve simple use metalinguistic abstraction prominent characteristic lisp also allows programmers develop entirely new idiosyncratic conceptual vocabularies describe processes functions programs go tackling problem domain combined poor software documentation result lisp systems work quite well indeed quite well-structured design perspective comprehensible original coders anyone else willing invest time sift layers highly recursive code joel moses credited coining phrase 1970s apl like beautiful diamond – flawless beautifully symmetrical ca n't add anything try glue another diamond n't get bigger diamond lisp like ball mud add still ball mud – still looks like lisp moses strongly denies claiming instead called lisp bean bag always returns original shape
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Programming language topics
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tomasulo algorithm tomasulo ’ algorithm computer architecture hardware algorithm dynamic scheduling instructions allows out-of-order execution enables efficient use multiple execution units developed robert tomasulo ibm 1967 first implemented ibm system/360 model 91 ’ floating point unit major innovations tomasulo ’ algorithm include register renaming hardware reservation stations execution units common data bus cdb computed values broadcast reservation stations may need developments allow improved parallel execution instructions would otherwise stall use scoreboarding earlier algorithms robert tomasulo received eckert–mauchly award 1997 work algorithm following concepts necessary implementation tomasulo algorithm common data bus cdb connects reservation stations directly functional units according tomasulo preserves precedence encouraging concurrency two important effects instructions issued sequentially effects sequence instructions exceptions raised instructions occur order would in-order processor regardless fact executed out-of-order i.e non-sequentially tomasulo algorithm uses register renaming correctly perform out-of-order execution general-purpose reservation station registers hold either real value placeholder value real value unavailable destination register issue stage placeholder value initially used placeholder value tag indicating reservation station produce real value unit finishes broadcasts result cdb placeholder replaced real value functional unit single reservation station reservation stations hold information needed execute single instruction including operation operands functional unit begins processing free source operands needed instruction real practically speaking may exceptions enough status information exception available case processor may raise special exception called imprecise exception imprecise exceptions occur non-oooe implementations processor state changed program order see risc pipeline exceptions programs experience precise exceptions specific instruction took exception determined restart re-execute point exception however experience imprecise exceptions generally restart re-execute system determine specific instruction took exception three stages listed stages instruction passes time issued time execution complete issue stage instructions issued execution operands reservation stations ready else stalled registers renamed step eliminating war waw hazards execute stage instruction operations carried instructions delayed step operands available eliminating raw hazards program correctness maintained effective address calculation prevent hazards memory write result stage alu operations results written back registers store operations written back memory concepts reservation stations register renaming common data bus tomasulo algorithm presents significant advancements design high-performance computers reservation stations take responsibility waiting operands presence data dependencies inconsistencies varying storage access time circuit speeds thus freeing functional units improvement overcomes long floating point delays memory accesses particular algorithm tolerant cache misses additionally programmers freed implementing optimized code result common data bus reservation station working together preserve dependencies well encouraging concurrency tracking operands instructions reservation stations register renaming hardware algorithm minimizes read-after-write raw eliminates write-after-write waw write-after-read war computer architecture hazards improves performance reducing wasted time would otherwise required stalls equally important improvement algorithm design limited specific pipeline structure improvement allows algorithm widely adopted multiple-issue processors additionally algorithm easily extended enable branch speculation tomasulo algorithm outside ibm unused several years implementation system/360 model 91 architecture however saw vast increase usage 1990s 3 reasons many modern processors implement dynamic scheduling schemes derivative tomasulo ’ original algorithm including popular intel x86-64 chips
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Computer architecture
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list linux adopters linux adopters organizations individuals moved operating systems linux local governments come pressure institutions world trade organization international intellectual property alliance turned linux free software affordable legal alternative pirated software expensive proprietary computer products microsoft apple commercial companies spread linux affords leverage countries companies developed world bid government contracts since low-cost option exists furnishing alternative path development countries like india pakistan many citizens skilled computer applications afford technological investment first world prices cost factor one considered though – many governmental institutions public military sectors north america european union make transition linux due superior stability openness source code turn leverages information security linux often used technical disciplines universities research centres due several factors including linux available free charge includes large body free/open-source software extent technical competence computer science software engineering academics also contributor stability maintainability upgradability ibm ran advertising campaign entitled linux education featuring young boy supposed linux examples large scale adoption linux education include following linux used extensively servers businesses long time linux also used corporate environments desktop platform employees commercially available solutions including red hat enterprise linux suse linux enterprise desktop ubuntu
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Operating systems
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hazard computer architecture domain central processing unit cpu design hazards problems instruction pipeline cpu microarchitectures next instruction execute following clock cycle potentially lead incorrect computation results three common types hazards data hazards structural hazards control hazards branching hazards several methods used deal hazards including pipeline stalls/pipeline bubbling operand forwarding case out-of-order execution scoreboarding method tomasulo algorithm instructions pipelined processor performed several stages given time several instructions processed various stages pipeline fetch execute many different instruction pipeline microarchitectures instructions may executed out-of-order hazard occurs two simultaneous possibly order instructions conflict data hazards occur instructions exhibit data dependence modify data different stages pipeline ignoring potential data hazards result race conditions also termed race hazards three situations data hazard occur consider two instructions occurring program order read write raw data hazard refers situation instruction refers result yet calculated retrieved occur even though instruction executed prior instruction prior instruction processed partly pipeline example first instruction calculating value saved register second going use value compute result register however pipeline operands fetched 2nd operation results first yet saved hence data dependency occurs data dependency occurs instruction dependent completion instruction write read war data hazard represents problem concurrent execution example situation chance may finish i.e. concurrent execution must ensured result register stored chance fetch operands write write waw data hazard may occur concurrent execution environment example write back wb must delayed finishes executing structural hazard occurs part processor hardware needed two instructions time canonical example single memory unit accessed fetch stage instruction retrieved memory memory stage data written and/or read memory often resolved separating component orthogonal units separate caches bubbling pipeline detected using hazard control unit branching hazards also termed control hazards occur branches many instruction pipeline microarchitectures processor know outcome branch needs insert new instruction pipeline normally fetch stage bubbling pipeline also termed pipeline break pipeline stall method preclude data structural branch hazards instructions fetched control logic determines whether hazard could/will occur true control logic inserts pipeline thus next instruction would cause hazard executes prior one sufficient time finish prevent hazard number equals number stages pipeline processor cleared instructions proceed free hazards forms stalling introduce delay processor resume execution flushing pipeline occurs branch instruction jumps new memory location invalidating prior stages pipeline prior stages cleared allowing pipeline continue new instruction indicated branch several main solutions algorithms used resolve data hazards case out-of-order execution algorithm used task removing data dependencies delegated compiler fill appropriate number instructions dependent instructions ensure correct operation re-order instructions possible example write value 3 register 1 already contains 6 add 7 register 1 store result register 2 i.e following execution register 2 contain value 10 however i1 write 3 register 1 fully exit pipeline i2 starts executing means r1 contain value 3 i2 performs addition event i2 adds 7 old value register 1 6 register 2 contains 13 instead i.e error occurs i2 reads register 1 i1 committed/stored result write operation register 1 i2 reading contents register 1 register 1 still contains 6 3 forwarding described helps correct errors depending fact output i1 3 used subsequent instructions value 3 committed to/stored register 1 forwarding applied example means wait commit/store output i1 register 1 example output 3 making output available subsequent instruction case i2 effect i2 uses correct recent value register 1 commit/store made immediately pipelined forwarding enabled instruction decode/execution id/ex stage pipeline two inputs value read register specified example value 6 register 1 new value register 1 example value 3 sent next stage instruction execute/memory access ex/mem added control logic used determine input use avoid control hazards microarchitectures event branch causes pipeline bubble incorrect instructions entered pipeline care must taken prevent wrongly-loaded instructions effect processor state excluding energy wasted processing discovered loaded incorrectly memory latency another factor designers must attend delay could reduce performance different types memory different accessing time memory thus choosing suitable type memory designers improve performance pipelined data path
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Computer architecture
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visual cloud visual cloud implementation visual computing applications rely cloud computing architectures cloud scale processing storage ubiquitous broadband connectivity connected devices network edge devices cloud data centers model providing visual computing services consumers business users allowing service providers realize general benefits cloud computing low cost elastic scalability high availability providing optimized infrastructure visual computing application requirements rise cloud computing enabled convergence powerful low-cost computer hardware high-capacity networks advances hardware virtualization satisfy high consumer demand visually-based entertainment video gaming well online social interaction service providers began deploy visually oriented applications centralized data centers use distributed content delivery networks make content accessible users mobile consumption video content particular makes cloud delivery video attractive remote processing storage compensate limitations mobile devices much 75 world ’ mobile data traffic expected video 2020 first generation visual cloud technologies mostly oriented around streaming media applications mid-2000s saw introduction professional user generated video-on-demand services like netflix youtube multiplayer online games mogs like call duty massively multiplayer online games mmogs like world warcraft another common usage visual cloud emerged timeframe desktop virtualization based remote desktop instances hosted using cloud infrastructure visual cloud technology become capable demanding usages begun emerge use visual cloud virtual reality augmented reality 3d scene understanding interactivity immersive live experiences visual cloud applications roughly divided four primary domains overall amount video delivered throughout world increasing significantly new sources develop processing distribution content may increasingly addressed means visual cloud sources content include applications cloud communications media/entertainment enterprise environments global mobile data traffic forecast increase nearly 7x 2016 2021 three primary models content distribution compute-intensive visual workloads media content creation delivery segment include media processing e.g. compression transcoding enhancement restoration compositing content stored data centers ultimately transmitted end-users workloads many others may applied content factors bit rate resolution tailored match transmission medium capabilities end-consumer device interactive 3d e.g. virtual desktop infrastructure batch rendering e.g. renderman operations may performed scale visual cloud usages user remote site rendering operations example usages domain include following varying requirements scale performance density among workloads implications cloud resources optimally support example visual cloud infrastructure support remote desktops would likely configured goal supporting greatest practical number desktop instances per server cloud game streaming hand requires far greater attention meeting peak graphics performance likely requiring lower density per server interactive usages also highly latency sensitive remote batch rendering values time completion latency playing far less important role computations based media visual cloud used manipulate provide deeper understanding media content well provide insights based users interact media analytics treats visual information unstructured data processed fed analytics engines interpretation images audio video implement usages web visual search autonomous transportation surveillance smart cities robotics visual computing technologies media analytics segment include three subdomains media analytics often makes use “ deep learning ” frameworks involve training algorithm using large amounts source data training portion approach typically takes place extended period time involves teaching algorithm mapping large amounts input data specific output classifications resulting trained algorithm make rapid instantaneous interpretations new input data based rules developed training stage making use capabilities three usage areas described i.e. media content creation delivery cloud graphics media analytics visual data manipulated based contents support emerging usages live panoramic video augmented virtual reality vr immersive reality gaming example builds game experience top physical surroundings player real time experiences consumed purpose-built displays vr head-mounted displays conventional devices pcs tablets phones visible usages technologies include google street view pokémon go commercially available examples immersive media include voke vr live streaming freed virtual replay technology facebook 360° photos oculus rift microsoft hololens vr goggles usages immersive media segment require compute-intensive scene analysis must often performed real time near-real time visual cloud applications workloads distributed end devices cloud example head-mounted display rendering might done locally user minimize latency live vr content distribution could done predominantly cloud
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Distributed computing architecture
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object resurrection object-oriented programming languages garbage collection object resurrection object comes back life process object destruction side effect finalizer executed object resurrection causes number problems particularly possibility object resurrection – even occur – makes garbage collection significantly complicated slower major reason finalizers discouraged languages deal object resurrection various ways solutions problems rare circumstances object resurrection used implement certain design patterns notably object pool circumstances resurrection undesired bug caused error finalizers general resurrection discouraged object resurrection occurs via following process first object becomes garbage longer reachable program may collected destroyed deallocated object destruction garbage collector deallocates object finalizer method may run may turn make object another garbage object reachable object finalizer reachable creating references finalizer may contain arbitrary code happens referenced object – necessarily finalized object – longer garbage deallocated otherwise references would become dangling references cause errors used generally program crash unpredictable behavior instead order maintain memory safety object returned life resurrected order detect garbage collector generally two-phase collection presence finalizers first finalize garbage finalizer re-check garbage garbage reachable objects finalizers case finalizers resurrected garbage adds overhead delays memory reclamation resurrected object may treated objects may treated specially many languages notably c java python python 3.4 objects finalized avoid possibility object repeatedly resurrected even indestructible c objects finalizers default finalized re-registered finalization cases resurrected objects considered errors notably objective-c treated identically objects notably python prior python 3.4 resurrected object sometimes called zombie term used various object states related object destruction usage depending language author zombie object specialized meaning objective-c however detailed zombie objects somewhat analogous zombie processes undergone termination state change close deallocation details significantly different .net framework notably c vb.net object resurrection instead refers state object finalization object brought back life inaccessible finalizer run returned inaccessible longer registered future finalization .net objects need finalization tracked object-by-object instead stored finalization queue rather notion resurrected objects sense article one speaks objects queued finalization objects re-enqueued finalization via codice_1 taking care multiply enqueue objects two main ways object resurrect another object creating reference object reach garbage reachable garbage reference non-garbage objects creating reference environment global variables cases static variables variables closure python examples follow object resurrecting also possible object resurrect objects collected given garbage collection cycle mechanisms resurrects creating reference object reach resurrects creating reference global environment examples cpython prior 3.4 run finalizers repeatedly objects garbage-collected cpython 3.4 later finalizers called objects garbage-collected second time become unreachable object resurrection causes large number problems languages adopted several different methods coping object resurrection commonly two-phase garbage collection presence finalizers prevent dangling references finalizing objects particularly marking objects finalized via flag ensure objects destroyed java free object proven object unreachable run finalizer python prior python 3.4 standard cpython implementation would treat resurrected objects identically objects never finalized making indestructible objects possible would garbage collect cycles contained object finalizer avoid possible problems object resurrection starting python 3.4 behavior largely java objects finalized marked already finalized garbage collection cycles two phases second phase checking resurrected objects objective-c 2.0 put resurrected objects zombie state log messages sent nothing else see also automatic reference counting zeroing weak references handling weak references .net framework notably c vb.net object finalization determined finalization queue checked object destruction objects finalizer placed queue creation dequeued finalizer called manually dequeued prior finalization codice_3 re-enqueued codice_4 thus default objects finalizers finalized finalization suppressed objects finalized multiple times resurrected made accessible re-enqueued finalization weak references default track resurrection meaning weak reference updated object resurrected called short weak references weak references track resurrection called long weak references object resurrection useful handle object pool commonly used objects obscures code makes confusing used objects may frequently used construction/destruction time-consuming example could array random numbers large number created destroyed short time actually small number use time object resurrection pooling technique would reduce unnecessary overhead creation destruction pool manager would get onto object stack information form reference object currently destructed pool manager keep object reuse later
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Operating systems
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ricoh 2a03 ricoh 2a03 rp2a03 ntsc version ricoh 2a07 rp2a07 pal version 8-bit microprocessor manufactured ricoh nintendo entertainment system video game console contained second sourced mos technology 6502 core modified disable 6502 binary-coded decimal mode 22 memory-mapped i/o registers controlled apu rudimentary dma game controller polling also used sound chip secondary cpu nintendo arcade games punch-out donkey kong 3 pal versions nes sold europe asia australia used ricoh 2a07 rp2a07 processor identical 2a03 except different clock divider 50 hz vertical refresh rate used pal television standard exception 16 hard-coded sampling rates delta modulation-encoded sample playback unit changes made order sampled sounds maintain original pitch rp2a03 new clock divider
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Computer architecture
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smack software smack full name simplified mandatory access control kernel linux kernel security module protects data process interaction malicious manipulation using set custom mandatory access control mac rules simplicity main design goal officially merged since linux 2.6.25 release main access control mechanism meego mobile operating system also used sandbox html5 web applications tizen architecture commercial wind river linux solutions embedded device development philips digital tv products. intel ostro os iot devices since 2016 smack required automotive grade linux agl implementations provides association linux facilities base agl security framework smack consists three components smack criticized written new lsm module instead selinux security policy provide equivalent functionality selinux policies proposed none demonstrated smack author replied would practical due selinux complicated configuration syntax philosophical difference smack selinux designs
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Operating systems
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nop code computer science nop no-op noop pronounced op short operation assembly language instruction programming language statement computer protocol command nothing computer instruction sets include instruction whose explicit purpose change state programmer-accessible registers status flags memory often takes well-defined number clock cycles execute instruction sets nop simulated executing instruction operands cause effect e.g sparc processor instruction codice_1 recommended solution nop commonly used timing purposes force memory alignment prevent hazards occupy branch delay slot render void existing instruction jump place-holder replaced active instructions later program development replace removed instructions reorganizing would problematic time-consuming cases nop minor side effects example motorola 68000 series processors nop opcode causes synchronization pipeline listed nop instruction cpu architectures hardware design point view unmapped areas bus often designed return zeroes since nop slide behavior often desirable gives bias coding all-zeroes opcode nop sometimes used description action performed function sequence programming language statements function code effect might also called redundant code common compiler optimization detection removal kind code code may required grammar programming language allow blank ada codice_2 statement serves nop syntax forbids control statements functions empty codice_2 statement must used specify action required thus programmer forgets write sequence statements program fail compile second line example single c statement behaves like nop practice compilers generate code statement statement performs addition discards result indeed statement without side effects affect control flow e.g. break return removed result computation discarded simplest possible statement c behaves like nop so-called null statement semi-colon context requiring statement compiler required generate nop instruction case typically instructions whatsoever would generated alternatively empty block compound statement may used may legible cases body function block must used empty c statements empty – simple statements must end semicolon compound statements enclosed braces need following semicolon thus contexts statement grammatically required null statement used null statement useless syntactic use wider context e.g. within context loop alternatively tersely note last form may confusing generates warning compilers compiler options semicolon usually indicates end function call instruction placed round parenthesis end line code continues calling function getchar returns \n newline character essentially fast-forwarding current reading location standard input beginning next line fortran codice_4 statement used contexts last statement loop although used anywhere functionality c used used null statement fact due specification language begin end block semicolon optional end statement thus semicolon used superfluous also block consisting codice_5 may used placeholder indicate action even placed inside another begin end block python programming language codice_6 statement effect executed thus serves nop primarily used ensure correct syntax due python indentation-sensitive syntax example syntax definition class requires indented block class logic expressed codice_6 empty jquery library provides function codice_8 nothing angular framework provides angular.noop function performs operations 'codice_9 colon character shell builtin similar effect nop do-nothing operation technically nop changes special parameter exit status last command 0 may considered synonym shell builtin 'true exit status true 0 lodash library provides function codice_10 returns undefined nothing many computer protocols telnet include nop command client issue request response server without requesting actions command used ensure connection still alive server responsive noop command part following protocols partial list note unlike protocols listed imap4 noop command specific purpose allows server send pending notifications client telnet ftp servers respond noop command ok +ok programmers added quirky responses client example codice_11 daemon minix responds noop message nops often involved cracking software checks serial numbers specific hardware software requirements presence absence hardware dongles etc accomplished altering functions subroutines bypass security checks instead simply return expected value checked instructions security check routine unused would replaced nops thus removing software security functionality without attracting attention nop opcode used form nop slide allows code execute exact value instruction pointer indeterminate e.g. buffer overflow causes function return address stack overwritten
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Computer architecture
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esobi esobi integrated desktop-based information management tool standalone news aggregator delivered worldwide acer computers esobi shareware application full version esobi consists four functions 1 rss reader 2 podcast receiver 3 meta-search engine 4 data library esobi supports 32-bit 64-bit windows 7 windows vista well windows xp esobi first developed esobi inc. taipei taiwan 2006 windows computers started first market combine rss reader meta-search engine scrapbook one application aiming ease information overload web recent updates september 2009 added podcast receiver features new ui design since 2008 acer bundled simpler version esobi computers including popular netbook acer aspire one version esobi includes rss reader data library free purchase acer computers esobi also software partner transcend information inc. 90-day trial version delivered selected transcend jetflash usb flash drives esobi windows mobile android platforms also available esobi received cnet download.com 5-star editor ’ review softpedia 4-star “ good ” editor ’ review 2009
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Internet protocols
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promiscuous mode computer networking promiscuous mode mode wired network interface controller nic wireless network interface controller wnic causes controller pass traffic receives central processing unit cpu rather passing frames controller specifically programmed receive mode normally used packet sniffing takes place router computer connected wired network one part wireless lan interfaces placed promiscuous mode software bridges often used hardware virtualization ieee 802 networks ethernet ieee 802.11 frame includes destination mac address non-promiscuous mode nic receives frame drops unless frame addressed nic mac address broadcast multicast addressed frame promiscuous mode however nic allows frames thus allowing computer read frames intended machines network devices many operating systems require superuser privileges enable promiscuous mode non-routing node promiscuous mode generally monitor traffic nodes within broadcast domain ethernet ieee 802.11 ring token ring computers attached ethernet hub satisfy requirement network switches used combat malicious use promiscuous mode router may monitor traffic routes promiscuous mode often used diagnose network connectivity issues programs make use feature show user data transferred network protocols like ftp telnet transfer data passwords clear text without encryption network scanners see data therefore computer users encouraged stay away insecure protocols like telnet use secure ones ssh promiscuous mode used malicious way capture private data transit network computer security professionals might interested detecting network devices promiscuous mode promiscuous mode software might send responses frames even though addressed another machine however experienced sniffers prevent e.g. using carefully designed firewall settings example sending ping icmp echo request wrong mac address right ip address adapter operating normal mode drop frame ip stack never sees responds adapter promiscuous mode frame passed ip stack machine mac address meaning respond would ping sniffer prevent configuring firewall block icmp traffic following applications applications classes use promiscuous mode
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Computer security
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opensparc opensparc open-source hardware project started december 2005 initial contribution project sun microsystems register-transfer level rtl verilog code full 64-bit 32-thread microprocessor ultrasparc t1 processor march 21 2006 sun released source code t1 ip core gnu general public license v2 full opensparc t1 system consists 8 cores one capable executing four threads concurrently total 32 threads core executes instruction order logic split among 6 pipeline stages december 11 2007 sun also made ultrasparc t2 processor rtl available via opensparc project also released gnu general public license v2 opensparc t2 8 cores 16 pipelines 64 threads
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Computer architecture
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nufw nufw software package extends netfilter linux kernel-internal packet filtering firewall module nufw adds authentication filtering rules nufw also provided hardware firewall edenwall firewalling appliance nufw restarted ffi renamed ufwi nufw ufwi extension netfilter brings notion user ip filtering nufw ufwi nufw ufwi refuses idea ip == user ip address easily spoofed thus uses algorithm perform authentication depends two subsystems nufw connected netfilter nuauth connected clients nufw algorithm following algorithm realizes posteriori authentication connection time-based association ensures identity user sent packet nufw real authentication firewall never associates user machine
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Computer security
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libwww libwww library world wide web modular client-side web api unix windows also name reference implementation libwww api used applications varying sizes including web browsers editors internet bots batch tools pluggable modules provided libwww add support http/1.1 caching pipelining post digest authentication deflate purpose libwww serve testbed protocol experiments software developers reinvent wheel libcurl considered modern replacement libwww 1991 1992 tim berners-lee student cern named jean-françois groff rewrote various components original worldwideweb browser nextstep operating system portable c code order demonstrate potential world wide web beginning libwww referred common library available separate product becoming generally available libwww integrated cern program library cernlib july 1992 library ported decnet may 1993 world wide web newsletter berners-lee announced common library called libwww licensed public domain encourage development web browsers initially considered releasing software gnu general public license rather public domain decided due concerns large corporations ibm would deterred using restrictions gpl rapid early development library caused robert cailliau problems integrating macwww browser 25 november 1994 version 2.17 henrik frystyk nielsen responsible libwww 21 march 1995 release version 3.0 cern put full responsibility libwww world wide web consortium w3c 1995 onwards line mode browser longer released separately part libwww package w3c created arena web browser testbed testing tool html3 css png features like libwww beta 3 arena replaced amaya 2 september 2003 w3c stopped development library due lack resources expectation development would come open source community libwww supports following protocols features include libwww supports plug-ins 19 applications used libwww integrated applications libwww developers libcurl criticised libwww portable thread-safe lacking several http authentication types neither libcurl libwww lightweight enough projects
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Web technology
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content addressable network content addressable network distributed decentralized p2p infrastructure provides hash table functionality internet-like scale one original four distributed hash table proposals introduced concurrently chord pastry tapestry like distributed hash tables designed scalable fault tolerant self-organizing architectural design virtual multi-dimensional cartesian coordinate space type overlay network multi-torus n-dimensional coordinate space virtual logical address completely independent physical location physical connectivity nodes points within space identified coordinates entire coordinate space dynamically partitioned among nodes system every node possesses least one distinct zone within overall space node maintains routing table holds ip address virtual coordinate zone neighbors node routes message towards destination point coordinate space node first determines neighboring zone closest destination point looks zone node ip address via routing table join joining node must find node already overlay network bootstrapping nodes may used inform joining node ip addresses nodes currently overlay network joining node receives ip address node already attempt identify zone joining node randomly picks point coordinate space sends join request directed random point one received ip addresses nodes already overlay network route join request correct device via zone-to-ip routing tables node managing destination point zone receives join request may honor join request splitting zone half allocating first half allocating joining node second half honor join request joining node keeps picking random points coordinate space sending join requests directed random points successfully joins network zone split allocation complete neighboring nodes updated coordinates two new zones corresponding ip addresses routing tables updated updates propagated across network handle node departing must detecting node departure done instance via heartbeat messages periodically broadcast routing table information neighbors predetermined period silence neighbor neighboring node determined failed considered departing node alternatively node willingly departing may broadcast notice neighbors departing node identified zone must either merged taken first departed node zone analyzed determine whether neighboring node zone merge departed node zone form valid zone example zone 2d coordinate space must either square rectangle l-shaped validation test may cycle neighboring zones determine successful merge occur one potential merges deemed valid merge zones merged none potential merges deemed valid neighboring node smallest zone takes control departing node zone take-over take-over node may periodically attempt merge additionally controlled zones respective neighboring zones merge successful routing tables neighboring zones nodes updated reflect merge network see subsection overlay network one single zone merge treat routing processing mindset effectuate take-over take-over node updates neighboring zones nodes routing tables requests either zone resolve take-over node network still sees subsection overlay network two separate zones treats routing processing mindset sylvia ratnasamy paul francis mark handley richard karp scott shenker
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Distributed computing architecture
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synonym database synonym alias alternate name table view sequence schema object used mainly make easy users access database objects owned users hide underlying object identity make harder malicious program user target underlying object synonym alternate name object requires storage definition application uses synonym dbms forwards request synonym underlying base object coding programs use synonyms instead database object names insulate changes name ownership object locations frequently refer database object long name might appreciate able refer shorter name without rename alter code referring synonyms powerful point view allowing users access objects lie within schema synonyms created explicitly create synonym command underlying objects located database databases connected two major uses synonyms create table procedure created schema users access using schema name prefix object name way around schema owner creates synonym name table name public synonyms owned special schema oracle database called public mentioned earlier public synonyms referenced users database public synonyms usually created application owner tables objects procedures packages users application see objects following code shows create public synonym employee table user see table typing original table name wish could provide different table name table create synonym statement remember dba must create public synonyms see table public private synonym ’ mean also perform select insert update delete operations table able perform operations user needs specific privileges underlying object either directly roles application owner private synonym synonym within database schema developer typically uses mask true name table view stored procedure database object application schema private synonyms unlike public synonyms referenced schema owns table object may want create private synonyms want refer table different contexts private synonym overrides public synonym definitions create private synonyms way create public synonyms omit public keyword create statement following example shows create private synonym called addresses locations table note create private synonym refer synonym exactly would original table name synonyms private public dropped manner using drop synonym command one important difference dropping public synonym need add keyword public keyword drop all_synonyms dba_synonyms view provides information synonyms database
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Databases
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noisy text analytics noisy text analytics process information extraction whose goal automatically extract structured semistructured information noisy unstructured text data text analytics growing mature field great value huge amounts data produced processing noisy text gaining importance lot common applications produce noisy text data noisy unstructured text data found informal settings online chat text messages e-mails message boards newsgroups blogs wikis web pages also text produced processing spontaneous speech using automatic speech recognition printed handwritten text using optical character recognition contains processing noise text produced circumstances typically highly noisy containing spelling errors abbreviations non-standard words false starts repetitions missing punctuations missing letter case information pause filling words “ um ” “ uh ” texting speech disfluencies text seen large amounts contact centers chat rooms optical character recognition ocr text documents short message service sms text etc documents historical language also considered noisy respect today knowledge language text contains important historical religious ancient medical knowledge useful nature noisy text produced contexts warrants moving beyond traditional text analysis techniques missing punctuation use non-standard words often hinder standard natural language processing tools part-of-speech tagging parsing techniques learn noisy data able process noisy data developed
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Computational linguistics
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semantic heterogeneity semantic heterogeneity database schema datasets domain developed independent parties resulting differences meaning interpretation data values beyond structured data problem semantic heterogeneity compounded due flexibility semi-structured data various tagging methods applied documents unstructured data semantic heterogeneity one important sources differences heterogeneous datasets yet multiple data sources interoperate one another essential reconcile semantic differences decomposing various sources semantic heterogeneities provides basis understanding map transform data overcome differences one first known classification schemes applied data semantics william kent two decades ago kent approach dealt structural mapping issues differences meaning pointed data dictionaries potentially solving one comprehensive classifications pluempitiwiriyawej hammer classification scheme semantic schematic heterogeneities xml data sources classify heterogeneities three broad classes moreover mismatches conflicts occur set elements population mismatch attributes description mismatch michael bergman expanded upon schema adding fourth major explicit category language also added examples kind semantic heterogeneity resulting 40 distinct potential categories table shows combined 40 possible sources semantic heterogeneities across sources different approach toward classifying semantics integration approaches taken sheth et al concept split semantics three forms implicit formal powerful implicit semantics either largely present easily extracted formal languages though relatively scarce occur form ontologies description logics powerful soft semantics fuzzy limited rigid set-based assignments sheth et al main point first-order logic fol description logic inadequate alone properly capture needed semantics besides data interoperabiity relevant areas information technology depend reconciling semantic heterogeneities include data mapping semantic integration enterprise information integration among many others conceptual actual data differences perspective vocabularies measures conventions two data sources brought together explicit attention semantic heterogeneities one means get information integrate interoperate mere twenty years ago information technology systems expressed stored data multitude formats systems internet web protocols done much overcome sources differences large number categories semantic heterogeneity categories also patterned anticipated corrected patterned sources inform kind work must done overcome semantic differences still reside
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Computer architecture
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branch computer science branch instruction computer program cause computer begin executing different instruction sequence thus deviate default behavior executing instructions order branch branching branched may also refer act switching execution different instruction sequence result executing branch instruction branch instructions used implement control flow program loops conditionals i.e. executing particular sequence instructions certain conditions satisfied branch instruction either unconditional branch always results branching conditional branch may may cause branching depending condition also depending specifies address new instruction sequence target address branch instruction generally classified direct indirect relative meaning instruction contains target address specifies target address found e.g. register memory location specifies difference current target addresses mechanically branch instruction change program counter pc cpu program counter stores memory address next instruction executed therefore branch cause cpu begin fetching instructions different sequence memory cells branch taken cpu program counter set argument jump instruction next instruction becomes instruction address memory therefore flow control changes branch taken cpu program counter unchanged therefore next instruction executed instruction branch instruction therefore flow control unchanged term branch used referring programs high level languages well programs written machine code assembly language high-level programming languages branches usually take form conditional statements various forms encapsulate instruction sequence executed conditions satisfied unconditional branch instructions goto used unconditionally jump begin execution different instruction sequence machine level branch instructions sometimes called jump instructions machine level jump instructions typically unconditional conditional forms latter may taken taken depending condition usually distinct forms one-way jumps often called jump subroutine invocations known call automatically save originating address return address stack allowing single subroutine invoked multiple locations code cpus flag registers earlier instruction sets condition flag register earlier instruction may arithmetic logic instruction often close branch though necessarily instruction immediately branch stored condition used branch jump overflow-flag set temporary information often stored flag register may also located elsewhere flag register design simple slower simple computers fast computers flag register place bottleneck speed instructions could otherwise operate parallel several execution units need set flag bits particular sequence also machines particular instructions condition may checked jump instruction branch label register x negative simple computer designs comparison branches execute arithmetic use power flag register branches fast computer designs comparison branches run faster flag register branches comparison branches access registers parallelism using cpu mechanisms calculation early simple cpu architectures still found microcontrollers may implement conditional jump rather conditional skip next instruction operation conditional jump call thus implemented conditional skip unconditional jump call instruction depending computer architecture assembly language mnemonic jump instruction typically shortened form word jump word branch often along informative letters extra parameter representing condition sometimes details included well range jump offset size special addressing mode used locate actual effective offset table lists machine level branch jump instructions found several well-known architectures achieve high performance modern processors pipelined consist multiple parts partially process instruction feed results next stage pipeline start working next instruction program design expects instructions execute particular unchanging sequence conditional branch instructions make impossible know sequence conditional branches cause stalls pipeline restarted different part program several techniques improve speed reducing stalls conditional branches historically branch prediction took statistics used result optimize code programmer would compile test version program run test data test code counted branches actually taken statistics test code used compiler optimize branches released code optimization would arrange fastest branch direction taken would always frequently taken control flow path permit cpus must designed least predictable branch timing cpus instruction sets power isa designed branch hints compiler tell cpu branch taken problem software branch prediction requires complex software development process run software hardware branch predictors moved statistics electronics branch predictors parts processor guess outcome conditional branch processor logic gambles guess beginning execute expected instruction flow example simple hardware branch prediction scheme assume backward branches i.e smaller program counter taken part loop forward branches larger program counter taken leave loop better branch predictors developed validated statistically running simulation variety test programs good predictors usually count outcomes previous executions branch faster expensive computers run faster investing better branch prediction electronics cpu hardware branch prediction branch hints let compiler presumably superior branch prediction override hardware simplistic branch prediction logic written without branches fewer branches often possible use bitwise operations conditional moves branch predication instead branches another technique branch delay slot approach one instruction branch always executed therefore computer use instruction useful work whether pipeline stalls approach historically popular risc computers family compatible cpus complicates multicycle cpus pipeline faster cpus longer-than-expected pipelines superscalar cpus execute instructions order
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Computer architecture
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hp network management center hp network management center nmc suite integrated hp software solutions used network managers information technology departments solutions allows network operators see catalog monitor routers switches devices network alerts staff network device fails predicts network node connection point may go designed improve operational efficiency hp longer packages network management solutions hp network management center hp offers automation orchestration cloud management software automating lifecycle services.. hp software assets first became part hewlett packard enterprise finally micro focus hp bsa security compliance subscription service attacks vulnerabilities automation providing industry compliance security alerts hp business service automation bsa software alerts come vendor bulletins agencies like national vulnerability database pci security standards council center internet security originally acquired stratavia 2010 hp database middleware automation software automates administrative tasks like provisioning configuration compliance patching release management associated databases application servers version 10 announced may 2013 hp network automation software designed simplify management complex distributed multi-vendor networks large enterprise data centers provides process-powered automation automate complete operational lifecycle network devices provisioning policy-based change management compliance security administration hp network node manager nnmi 10.00 hp nnmi smart plug-in modules use continuous spiral discovery network discovery technology provides up-to-date network topology root cause analysis allows network administrators ascertain level congestion networks identify root cause congestion product helps departments monitor networks isolate issues find outages improve network availability performance solution supports multitenancy architecture including tenant user-level map incident security allows teams manage customers departments sites one console hp network node manager smart plug-in modules ispis extend hp network node manager software ’ nnmi fault availability management hp nnm ispis performance advanced network services hp smart plug-ins integrate fault availability performance advanced network services physical virtualized network infrastructure allow network operators determine display network fault availability performance advanced services status one view progress unified workflow drill context hp automated network management anm software bundles hp network node manager hp network automation several hp smart plug-ins unify network fault availability change configuration compliance performance monitoring automated diagnostics single solution package hp network node manager delivers common console unified fault performance configuration networks second product bundle hp nnm ispis performance metrics traffic quality assurance designed monitor ensure performance network third product bundle hp ispi network engineering toolset net automates common operator tasks provides trap analytics map export capabilities hp network automation handles network change configuration management fourth product bundle hp operations orchestration software creates “ runbooks ” automate provisioning infrastructure deployment faster automated previously version 10 announced may 2013 out-of-the-box support 5,000 operations including amazon s3 storage hp arcsight hp fortify openstack sap applications hp server automation software provides enterprise server lifecycle automation tasks provisioning patching configuration compliance version 10 announced may 2013 allows organizations deploy maintain patching updating thousands servers version also update virtual servers sleeping well active may 2013 hp also released hp server automation software appliance called hp server automation standard includes much core configuration deployment compliance checking functionality found full software edition hp storage essentials single tool provides storage optimization capacity planning june 2013 hp announced version 9.6 expanded support third-party storage arrays including emc vnx block storage brocade access gateway also provided deeper integration hp 3par hp 6000 eva management server development support oracle sap business objects
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Distributed computing architecture
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php standard recommendation php standard recommendation psr php specification published php framework interop group similar java specification request java serves standardization programming concepts php aim enable interoperability components provide common technical basis implementation proven concepts optimal programming testing practices php-fig formed several php frameworks founders psr suggested members voted according established protocol act consistently line agreed upon processes php-fig official website psr documentation follows nowiki rfc 2119 /nowiki written scott bradner march 1997 harvard university
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Programming language topics
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optical add-drop multiplexer optical add-drop multiplexer oadm device used wavelength-division multiplexing systems multiplexing routing different channels light single mode fiber smf type optical node generally used formation construction optical telecommunications networks add drop refer capability device add one new wavelength channels existing multi-wavelength wdm signal and/or drop remove one channels passing signals another network path oadm may considered specific type optical cross-connect traditional oadm consists three stages optical demultiplexer optical multiplexer method reconfiguring paths demultiplexer multiplexer set ports adding dropping signals demultiplexer separates wavelengths input fiber onto ports reconfiguration achieved fiber patch panel optical switches direct wavelengths multiplexer drop ports multiplexer multiplexes wavelength channels continue demultiplexer ports add ports onto single output fiber lightpaths directly pass oadm termed cut-through lightpaths added dropped oadm node termed added/dropped lightpaths oadm remotely reconfigurable optical switches example 1×2 middle stage called reconfigurable oadm roadm ones without feature known fixed oadms term oadm applies types often used interchangeably roadm physically several ways make oadm variety demultiplexer multiplexer technologies including thin film filters fiber bragg gratings optical circulators free space grating devices integrated planar arrayed waveguide gratings switching reconfiguration functions range manual fiber patch panel variety switching technologies including microelectromechanical systems mems liquid crystal thermo-optic switches planar waveguide circuits although add/drop functionality oadms distinct add-drop multiplexers former function photonic domain wavelength-division multiplexing latter implicitly considered function traditional sonet/sdh networks
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Internet protocols
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caudium web server caudium open source web server originally created fork roxen challenger server server written c pike pike also used create extensions server caudium different apache configuration process different directory structure different generally languages used program server extensions dynamic pages different although support php according caudium website caudium offers different performance profile apache n't fork external processes making better suited cope sudden spikes traffic
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Web technology
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security token security token physical device used gain access electronically restricted resource token used addition place password acts like electronic key access something examples include wireless keycard opening locked door case customer trying access bank account online use bank-provided token prove customer claim tokens may store cryptographic keys may used generate digital signature biometric data fingerprint details may also store passwords designs incorporate tamper resistant packaging others may include small keypads allow entry pin simple button start generating routine display capability show generated key number connected tokens utilize variety interfaces including usb near-field communication nfc radio-frequency identification rfid bluetooth tokens audio capability designed vision-impaired people tokens contain secret information used prove identity four different ways information used time-synchronized one-time passwords change constantly set time interval e.g. per minute sort synchronization must exist client token authentication server disconnected tokens time-synchronization done token distributed client token types synchronization token inserted input device main problem time-synchronized tokens time become unsynchronized however systems rsa securid allow user resynchronize server token sometimes entering several consecutive passcodes also replaceable batteries last 5 years replaced – additional cost another type one-time password uses complex mathematical algorithm hash chain generate series one-time passwords secret shared key password unguessable even previous passwords known open source oauth algorithm standardized algorithms covered us patents password observably unpredictable independent previous ones wherefore adversary would unable guess next password may even knowledge previous passwords tokens contain chips functions varying simple complex including multiple authentication methods simplest security tokens need connection computer tokens physical display authenticating user simply enters displayed number log tokens connect computer using wireless techniques bluetooth tokens transfer key sequence local client nearby access point alternatively another form token widely available many years mobile device communicates using out-of-band channel like voice sms ussd still tokens plug computer may require pin depending type token computer os either read key token perform cryptographic operation ask token firmware perform operation related application hardware dongle required computer programs prove ownership software dongle placed input device software accesses i/o device question authorize use software question commercial solutions provided variety vendors proprietary often patented implementation variously used security features token designs meeting certain security standards certified united states compliant fips 140 federal security standard tokens without kind certification sometimes viewed suspect often meet accepted government industry security standards put rigorous testing likely provide level cryptographic security token solutions designs independently audited third-party agencies disconnected tokens neither physical logical connection client computer typically require special input device instead use built-in screen display generated authentication data user enters manually via keyboard keypad disconnected tokens common type security token used usually combination password two-factor authentication online identification connected tokens tokens must physically connected computer user authenticating tokens category automatically transmit authentication information client computer physical connection made eliminating need user manually enter authentication information however order use connected token appropriate input device must installed common types physical tokens smart cards usb tokens require smart card reader usb port respectively increasingly universal 2nd factor u2f tokens supported open specification group fido alliance become popular consumers mainstream browser support beginning 2015 supported popular websites social media sites older pc card tokens made work primarily laptops type ii pc cards preferred token half thick type iii audio jack port relatively practical method establish connection mobile devices iphone ipad android accessories well known device called square credit card reader iphone android use special purpose interface e.g crypto ignition key deployed united states national security agency tokens also used photo id card cell phones pdas also serve security tokens proper programming many connected tokens use smart card technology smart cards cheap around ten cents contain proven security mechanisms used financial institutions like cash cards however computational performance smart cards often rather limited extreme low power consumption ultra-thin form-factor requirements smart-card-based usb tokens contain smart card chip inside provide functionality usb tokens smart cards enable broad range security solutions provide abilities security traditional smart card without requiring unique input device computer operating system point view token usb-connected smart card reader one non-removable smart card present unlike connected tokens contactless tokens form logical connection client computer require physical connection absence need physical contact makes convenient connected disconnected tokens result contactless tokens popular choice keyless entry systems electronic payment solutions mobil speedpass uses rfid transmit authentication info keychain token however various security concerns raised rfid tokens researchers johns hopkins university rsa laboratories discovered rfid tags could easily cracked cloned another downside contactless tokens relatively short battery lives usually 5–6 years low compared usb tokens may last 10 years tokens however allow batteries changed thus reducing costs bluetooth low energy protocols serve long lasting battery lifecycle wireless transmission however automatic transmission power control antagonizes attempts radial distance estimates escape available apart standardised bluetooth power control algorithm provide calibration minimally required transmission power bluetooth tokens often combined usb token thus working connected disconnected state bluetooth authentication works closer 32 feet 10 meters bluetooth link properly operable token may inserted usb input device function another combination smart card store locally larger amounts identity data process information well another contactless ble token combines secure storage tokenized release fingerprint credentials usb mode operation sign-off requires care token mechanically coupled usb plug advantage bluetooth mode operation option combining sign-off distance metrics respective products preparation following concepts electronic leash near-field communication nfc tokens combined bluetooth token may operate several modes thus working connected disconnected state nfc authentication works closer 1 foot 0.3 meters nfc protocol bridges short distances reader bluetooth connection serves data provision token enable authentication also bluetooth link connected token may serve locally stored authentication information coarse positioning nfc reader relieves exact positioning connector types single sign-on sso solutions like enterprise single sign-on use token store software allows seamless authentication password filling passwords stored token users need remember passwords therefore select secure passwords secure passwords assigned usually tokens store cryptographic hash password token compromised password still protected programmable tokens marketed drop-in replacement mobile applications google authenticator miniotp used mobile app replacement well parallel backup means measures securing data may overcome applies well security tokens major threat incautious operation users shall aware permanent options threat simplest vulnerability password container theft loss device chances happening happening unawares reduced physical security measures locks electronic leash body sensor alarm stolen tokens made useless using two factor authentication commonly order authenticate personal identification number pin must entered along information provided token time output token system allows users authenticate via untrusted network internet vulnerable man-in-the-middle attacks type attack fraudster acts go-between user legitimate system soliciting token output legitimate user supplying authentication system since token value mathematically correct authentication succeeds fraudster granted access citibank made headline news 2006 hardware-token-equipped business users became victims large ukrainian-based man-in-the-middle phishing attack 2012 prosecco research team inria paris-rocquencourt developed efficient method extracting secret key several pkcs 11 cryptographic devices including securid 800 findings documented inria technical report rr-7944 id hal-00691958 published crypto 2012 trusted regular hand-written signature digital signature must made private key known person authorized make signature tokens allow secure on-board generation storage private keys enable secure digital signatures also used user authentication private key also serves proof user ’ identity tokens identify user tokens must kind number unique approaches fully qualify digital signatures according national laws tokens on-board keyboard another user interface used signing scenarios confirming bank transaction based bank account number funds transferred
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Computer security
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nokia c5-03 nokia c5-03 budget resistive touchscreen smartphone wlan cseries released december 2010 phone shazam music identification software social networking software included available download assisted gps ovi maps 3.0 integrated
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Operating systems
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vp/css vp/css time-sharing operating system developed national css began life 1968 copy ibm cp/cms time distributed ibm customers charge source code form without support part ibm type-iii library extensive in-house development today would termed software fork national css took vp/css different direction cp/cms although two systems would eventually share many capabilities technical implementations diverged substantive ways vp/css ran ibm ibm plug compatible hardware owned ncss customers site licenses including bank america standard oil california initial period running ibm system/360-67 platform used cp/cms vp/css ported system/370 series made possible ibm added virtual memory capabilities s/370 series 1972 vp/css notable supporting large numbers interactive users per machine compared ibm mainframe operating systems technical operations commercial factors played role making national css commercially viable service business vp/css shared basic architecture concepts cp/cms revolutionary time control program called cp cp/cms vp vp/css created multiple independent virtual machines vms implementing full virtualization underlying hardware – meaning time-sharing user provided private virtual machine appeared entire stand-alone computer capable running software could run bare machine including operating systems concept pioneered ibm research system cp-40 first version cp/cms design departure ibm monolithic operating systems isolating users improved system stability bug one user software could crash another user virtual machine underlying control program approach made cp/cms superior choice commercial time-sharing thus strong foundation national css broke new ground would become important new industry vm created vp ran simple single-user operating system called css derived ibm cambridge monitor system css allowed users run programs manipulate file system manage virtual devices since vp css began life cp cms respectively closely resembled systems particularly early days continuous development introduction new features vp/css ibm vm led significant differences time systems retained obvious family resemblance ibm decision add virtualization virtual memory features s/370 reflects success virtual machine approach time-sharing credit belated decision attributed ibm awareness commercial success national css 1968 founders national css saw cp/cms operating system would good foundation time-sharing business – system technical merits ability share mainframe resources among many interactive users availability source code form cost another firm interactive data corporation reached conclusion firm lured away key cp/cms technical personnel csc mit union carbide national css quickly discovered however cp/cms initial performance adequate sustain profitable operations – literally selling every available minute interactive time would pay 50k/month equipment lease crash technical project began improve performance led number fundamental enhancements soon allowed business make money thus began lengthy reimplementation effort would occupy large development team course fifteen years end lifespan vp/css diverged long way cp/cms roots boasted surprising array features would considered quite modern even today key enhancements original cp/cms system included changes dispatching algorithm paging system virtual memory course new concept time ibm system/360-67 address translation technology enabled various technical approaches ultimately vp/css page migration algorithm three-queue dispatcher became well-known ncss personnel eventually joined ibm thomas j. watson research center work vm technologies another area throughput improvement performance css single-user operating system one important change replacing channel command words ccws expensive simulated instructions something like today termed bios calls simulating complex s/360 i/o architecture virtualization amazing feat – done cp complex innermost core routine called ccwtrans i/o operations trapped within virtual machine however proved enormously cheaper make direct hypervisor calls targeted functions rather simulating operation low-level i/o commands vp/css done using paravirtualization via non-virtualized diag diagnose instruction technique used ibm cp/cms release 3.1 carried forward vm/370 unclear implementation came first – whether invented independently early national css technical efforts quickly established vp/css commercially viable version cp/cms vp/css reputed much better performance ibm reimplementation cp/cms vm/370 – turn reputed substantial performance advantage ibm preferred timesharing solution tso unfortunately documented period performance statistics hard find today however several data points support claims following relative performance believed accurate although documented sources remain located described history cp/cms ibm primary emphasis mvs successors core mainframe operating system led ibm waste substantial technical advantage represented vm/370 made possible independent vendor like ncss strike new territory industry observers pointed hardware vendor natural preference selling hardware increasing number users per machine ncss gained technical advantages ultimately became successful commercially despite fact optimization techniques used enhance vp css performance well understood well-documented literature day ultimately amdahl corporation publicized sales wins several large vp/css data centers ibm began pay public attention ncss technical innovations long thereafter time-sharing industry began feel pressure personal computer revolution need super-optimized multiuser mainframe operating system waned ncss moved away vp/css mid 80s retargeting nomad vm platforms unknown long ncss site-license customers continued use vp/css equipment though seems unlikely could continue long without ongoing ncss operating system support
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Operating systems
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netiq netiq enterprise software company based houston texas whose products provide identity access management security data center management flagship offerings netiq identity manager netiq access manager key software titles include appmanager secure configuration manager sentinel micro focus international owned netiq since 2014 mfi acquired attachmate acquired netiq 2006 six years latter acquired mission critical software .. netiq founded ching-fa hwang her-daw che hon wong ken prayoon cheng tom kemp september 1995 appmanager introduced 1996 february 2000 merger mission critical software widened company focus include systems management well performance 2001 netiq acquired webtrends whose software monitors corporate internet traffic 2006 netiq acquired attachmate attachmate acquired novell 2011 netiq added identity security products well data center virtualization offerings attachmate acquisition led today ’ alignment netiq products three categories 2014 attachmate merged micro focus international
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Computer security
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cleanup stack cleanup stack concept widely used symbian os suitable use places dynamic memory used allocated programming problem dynamic memory sole discretion underlying os whether request memory allocation shall succeed applications requester memory must prepared handle rejection large programs dynamic memory used almost everywhere application frequently adds code handle failure increase code size significantly symbian used mostly phones increase code size amplify memory allocation failures symbian features ingenious solution problem application notes memory allocation may fail places earlier allocated memory address location symbian aware location called cleanup stack event failure symbian knows whatever resource placed cleanup stack needs freed way resources freed program crashes leaves freeing performed automatically symbian os applications die peacefully without worrying would clean mess left cleanup stack make idea keep copy pointer allocated memory elements cleanup stack popped destroyed using push pop popanddestroy example
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Operating systems
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meet-in-the-middle attack meet-in-the-middle attack mitm generic space–time tradeoff cryptographic attack encryption schemes rely performing multiple encryption operations sequence mitm attack primary reason double des used triple des key 168-bit bruteforced attacker 2 space 2 operations trying improve security block cipher tempting idea encrypt data several times using multiple keys one might think doubles even n -tuples security multiple-encryption scheme depending number times data encrypted exhaustive search possible combination keys simple brute-force would take 2 attempts data encrypted k -bit keys n times mitm generic attack weakens security benefits using multiple encryptions storing intermediate values encryptions decryptions using improve time required brute force decryption keys makes meet-in-the-middle attack mitm generic space–time tradeoff cryptographic attack mitm attack attempts find keys using range ciphertext domain plaintext composition several functions block ciphers forward mapping first functions backward mapping inverse image last functions quite literally meeting middle composed function example although double des encrypts data two different 56-bit keys double des broken 2 encryption decryption operations multidimensional mitm md-mitm uses combination several simultaneous mitm attacks like described meeting happens multiple positions composed function diffie hellman first proposed meet-in-the-middle attack hypothetical expansion block cipher 1977 attack used space–time tradeoff break double-encryption scheme twice time needed break single-encryption scheme 2011 bo zhu guang gong investigated multidimensional meet-in-the-middle attack presented new attacks block ciphers gost ktantan hummingbird-2 assume someone wants attack encryption scheme following characteristics given plaintext p ciphertext c enc encryption function dec decryption function defined enc inverse mapping k k two keys naive approach brute-forcing encryption scheme decrypt ciphertext every possible k decrypt intermediate outputs every possible k total 2 2 2 operations meet-in-the-middle attack uses efficient approach decrypting c k one obtains following equivalence attacker compute enc p values k dec c possible values k total 2 2 2 k k size operations result enc p operations matches result dec c operations pair k k possibly correct key potentially-correct key called candidate key attacker determine candidate key correct testing second test-set plaintext ciphertext mitm attack one reasons data encryption standard des replaced triple des double des attacker use mitm attack bruteforce double des 2 operations 2 space making small improvement des triple des uses triple length 168-bit key also vulnerable meet-in-the-middle attack 2 space 2 operations considered secure due size keyspace compute following match found keep k k candidate key-pair table test pairs new pair confirm validity key-pair work new pair mitm new pair keysize k attack uses 2encryptions decryptions 2 memory case look-up table built set forward computations contrast naive attack needs 2 encryptions 1 space 1d-mitm efficient sophisticated attack developed multidimensional meet-in-the-middle attack also abbreviated md-mitm preferred data encrypted using 2 encryptions different keys instead meeting middle one place sequence md-mitm attack attempts reach several specific intermediate states using forward backward computations several positions cipher assume attack mounted block cipher encryption decryption defined plaintext p encrypted multiple times using repetition block cipher md-mitm used cryptanalysis among many gost block cipher shown 3d-mitm significantly reduced time complexity attack compute following possible guess intermediate state formula_18 compute following whether matches formula_38 case use found combination sub-keys formula_39 another pair plaintext/ciphertext verify correctness key note nested element algorithm guess every possible value done guess previous make element exponential complexity overall time complexity md-mitm attack time complexity attack without brute force formula_40⋅formula_41⋅formula_42 regarding memory complexity easy see formula_43 much smaller first built table candidate values formula_44 increases candidate values contained formula_45 must satisfy conditions thereby fewer candidates pass end destination formula_38 upper bound memory complexity md-mitm denotes length whole key combined data complexity depends probability wrong key may pass obtain false positive formula_48 intermediate state first mitm phase size intermediate state block size often considering also many keys left testing first mitm-phase formula_49 therefore first mitm phase formula_50 |⋅| denotes length main memory consumption restricted construction sets b much smaller others data complexity see subsection complexity md-mitm
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Computer security
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query flooding query flooding method search resource p2p network simple scales poorly thus rarely used early versions gnutella protocol operated query flooding newer versions use efficient search algorithms p2p network generally consists large number nodes connected nodes small subset nodes node wants find resource network may node know could simply broadcast search query immediate neighbours neighbours resource asks neighbours forward query neighbours turn repeated resource found nodes contacted perhaps network-imposed hop limit reached query flooding simple implement practical small networks requests contacts reachable nodes network precisely determine whether resource found network freenet example returns probabilistic result hand every request may cause every node contacted node might generate small number queries however query floods network thus larger network would generate far traffic per node smaller one making inherently unscalable additionally node flood network simply issuing request nonexistent resource could possible launch denial-of-service attack network version 0.6 gnutella protocol mandates query routing query routing specification explains ideas original research implemented file sharing networks kad network use distributed hash tables index files keyword searches bittorrent creates individual overlay networks sharing individual files archives searches performed mechanisms locating torrent files indexed web site similar mechanism use gnutella network magnet links instance bitzi provides web interface search magnet links earlier p2p networks napster used centralized database locate files scaling problem central server single point failure
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Internet protocols
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internet explorer mac os x internet explorer mac os x also referred internet explorer macintosh internet explorer macintosh edition internet explorer mac ie mac unsupported inactive proprietary web browser developed microsoft macintosh platform initial versions developed code base internet explorer windows later versions diverged particularly release version 5 included cutting edge fault-tolerant highly standards-compliant tasman layout engine result five-year agreement apple microsoft 1997 default browser classic mac os mac os x 1998 superseded apple safari web browser 2003 release mac os x 10.3 panther june 13 2003 microsoft announced ceasing development internet explorer mac final update released july 11 2003 browser included default installation mac os x 10.4 tiger released april 29 2005 microsoft stopped releases product december 31 2005 removed application macintosh downloads site january 31 2006 microsoft recommended users migrate recent web browsing technologies apple safari archived version download available softonic.com works mac os x 10.6 earlier versions discontinuation rosetta versions internet explorer macintosh released starting version 2 1996 version 5 received last patch 2003 ie versions mac typically lagged several months year behind windows versions included unique developments including layout engine tasman first version internet explorer macintosh operating system beta version internet explorer 2.0 macintosh released january 23 1996 free download microsoft website first version based spyglass mosaic web browser licensed spyglass available 68k ppc based macs running system 7.0.1 later supported embedding number multimedia formats web pages including avi quicktime formatted video aiff wav formatted audio final version released three months later april 23 version 2.1 released august year mostly aimed fixed bugs improving stability also added features support npapi first version internet explorer platform support quicktime vr aol 3.0 macintosh used ie 2.1 rendering engine built-in web browser november 5 1996 microsoft announced release beta version internet explorer version 3.0 macintosh release added support html version 3.2 cascading style sheets java applets activex controls final version made available january 8 1997 also added support ssl ntlm security protocols pics rsaci rating systems used control access websites based content ratings problem operating system extension used mac os called cfm68k runtime enabler led delay release version 3.0 macs based 68k line processors four months later may 14 microsoft released version 3.01 included version 68k-based machines version also included features windows version internet explorer 4.0 autocomplete monitoring favorites notified users sites favorites list updated also included support javascript introduced download manager cookie manager 1997 macworld expo boston august 6 steve jobs bill gates announced partnership microsoft apple amongst things apple agreed make internet explorer default browser instead netscape navigator five months later january 6 1998 macworld expo san francisco microsoft announced release final version internet explorer version 4.0 macintosh version 4 included support offline browsing dynamic html new faster java virtual machine security zones allow users administrators limit access certain types web content depending zone example intranet internet content coming publicized feature internet explorer 4.0 support microsoft active channel technology intended deliver regularly updated content users could personally tailor interests however active channel failed reach wide audience event apple announced release mac os 8.1 first version macintosh operating system bundle internet explorer default browser per agreement microsoft however version 4.0 ready time included version 3.01 bundled cds following year san francisco macworld expo january 9 1999 microsoft announced release internet explorer 4.5 macintosh edition new version dropped 68k processor support introduced form autofill print preview page holder pane let user hold page links one side screen opened pages right hand support mac os technology like sherlock year later january 5 2000 microsoft announced new version internet explorer san francisco macworld expo internet explorer 5 macintosh edition released two months later march 27 2000 windows version internet explorer 5 released year earlier used trident layout engine macintosh edition introduced new rendering engine called tasman designed compliant emerging w3c standards html 4.0 css level 1 dom level 1 ecmascript also introduced number features later added browsers complete support png image standard previous versions support doctype switching text zoom xml source view also included auction manager tracking auctions sites like ebay internet scrapbook allow users quickly easily store organize web content example image piece selected text preview releases browser included feature called mediabar integrated mp3 internet radio playback feature dropped final version initial release mac os 8 mac os 9 however two months release may 15 mac os x version released bundled mac os x dp4 release handed developers 2000 worldwide developers conference mac os x public beta included another preview mac os x version ie release mac os x 10.0 march 24 2001 included yet another preview mac os x version ie 5 updated later release mac os x v10.1 september 25 2001 included final version internet explorer 5.1 mac os x. ie 5.1 mac os 8 9 released december 18 2001 according jorg brown one ie mac developers microsoft version 5 team produced ie mac moved another project ie mac relegated something expected work spare time june 17 2002 microsoft announced release version 5.2 first mac os x-only release included performance security fixes support mac os x features likes quartz text smoothing 2002 microsoft reassigned developers develop version 6 internet explorer mac intended used base new product msn mac os x would subscription-only browser worked online msn service incorporate features like address book junk mail filters msn messenger client however hearing apple started development browser canceled standalone browser development concentrated msn browser released may 15 2003 june 13 2003 pc pro reported macintosh business unit general manager roz ho confirmed aside updates fix security problems would new versions internet explorer microsoft three days later june 16 2003 microsoft released final version mac os x ppc version 5.2.3 month later july 11 2003 released final version mac os 8 9 version 5.1.7 last versions internet explorer mac os x ppc distinguishing blue logo base logo used internet explorer 6 windows windows one lighter blue less 3-d features found internet explorer mac found common contemporary browsers possible exception internet explorer windows still features many browsers features found internet explorer mac contemporaries acid1 included offline easter egg accessible typing 'tasman internet explorer 5 mac os text replaced names developers
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Internet protocols
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exokernel exokernel operating system kernel developed mit parallel distributed operating systems group also class similar operating systems operating systems generally present hardware resources applications high-level abstractions virtual file systems idea behind exokernels force abstractions possible application developers enabling make many decisions possible hardware abstractions exokernels tiny since functionality limited ensuring protection multiplexing resources considerably simpler conventional microkernels implementation message passing monolithic kernels implementation high-level abstractions implemented applications called library operating systems may request specific memory addresses disk blocks etc kernel ensures requested resource free application allowed access low-level hardware access allows programmer implement custom abstractions omit unnecessary ones commonly improve program performance also allows programmers choose level abstraction want high low exokernels seen application end-to-end principle operating systems force application program layer abstractions top abstractions designed different requirements mind example mit exokernel project cheetah web server stores preformatted internet protocol packets disk kernel provides safe access disk preventing unauthorized reading writing disk abstracted application libraries application uses traditionally kernel designers sought make individual hardware resources invisible application programs requiring programs interact hardware via abstraction model models include file systems disk storage virtual address spaces memory schedulers task management sockets network communication abstractions hardware make easier write programs general limit performance stifle experimentation new abstractions security-oriented application might need file system leave old data disk reliability-oriented application might need file system keeps data failure recovery one option remove kernel completely program directly hardware entire machine would dedicated application written conversely entire application codebase would dedicated machine exokernel concept compromise let kernel allocate basic physical resources machine e.g disk blocks memory pages processor time multiple application programs let program decide resources program link support library implements abstractions needs implement mit developed two exokernel-based operating systems using two kernels aegis proof concept limited support storage xok applied exokernel concept thoroughly essential idea mit exokernel system operating system act executive small programs provided application software constrained requirement exokernel must able guarantee use hardware safely mit exokernel manages hardware resources follows available library operating systems exokernel include custom exos system emulator bsd addition exokernel team created cheetah web server uses kernel directly exokernel concept around since least 1994 exokernels still research effort used major commercial operating systems concept operating exokernel system nemesis written university cambridge university glasgow citrix systems swedish institute computer science mit also built several exokernel-based systems including exos
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Computer architecture
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threat matrix database threat matrix intelligence-based measure thorough assessments database program pakistani government officials military science circles use evaluating perceived external internal threats challenge national security pakistan development began 2011 government prime minister yousaf raza gillani program identifies military operational priorities goes beyond comprehensively describing existential non-existential threats country threat matrix program viewed become permanent fixture national security policy pakistan database comprehensive existence revealed political scientist dr. farrukh saleem work published news international 2013 earlier mentioned ispr press briefing given media published thesis saleem critically opined source existential threats always state actor non-state armed forces threat matrix two defined dimensions conventional threats sub-conventional threats conventional threats external threats national security outside country sub-conventional threats refer internal threats national security within country january 2013 major-general asif salim inter-services public relations ispr briefed news media new recent studies conducted pakistan military according ispr armed forces programmed conventional warfare current situation necessitated change forces fighting front-line tribal regions program according requirements sub-conventional warfare interview military scientist talat masood noted new doctrine india viewed 1 enemy first time realised pakistan faces real threat within threat concentrated areas along western borders conflict northwest closely tied war afghanistan factors like militant insurgency future us pullout afghanistan intertwined effect conflict pakistan according lieutenant-general khalid rabbani commander xi corps peshawar withdrawal foreign combat troops afghanistan since 2014 may trigger challenging ramifications pakistan terms threat matrix afghanistan leaving giving notion success taliban afghanistan notion success may snowballing effect threat matrix afghanistan along challenges posed western front india still retains important focus threat assessments pakistan civil-military foreign policy doctrine according express tribune editorial potential threat arch-rival india east effect state threat matrix western front dwindling capacity state cope terrorism owed pakistan 'vigilance eastern border pakistan static 'threat matrix expects india attack occupy pakistan never accepted creation pakistan harsh v. pant outlook india thinks pakistan fast-growing nuclear arsenal expanding greater rate india charged sociopolitical atmosphere country rapidly changing dynamics nuclear matrix region tactically underscores pakistani military establishment india-centric threat matrix 2016 pakistan navy revealed developing maritime doctrine response evolving conventional subconventional threat matrix region indian ocean doctrine would aim protect pakistan maritime interests region according j. berkshire miller diplomat military establishment pakistan meanwhile still views threat matrix india-centric lens—pakistan genuinely believes rightly wrongly india continues work aggressively strategic interests bribery espionage afghanistan comprehensive thesis minimum deterrence pakistan dilemma published royal united services institute rusi nuclear strategist theorist brigadier-general retired feroz hassan khan states pakistan threat matrix dramatically changed events 1971 war india nuclear bomb test 1974 country threat perception became dominated twin threat india conventional force superiority nuclear weapons capability acquisition nuclear weapons hence became pakistan highest national security objective unanimity across parts political spectrum augmented strong perception outside powers could relied upon moments crisis war term also economic connotations instance us secretary state hillary clinton outlined downturn global financial crisis effect pakistan especially context war militancy economic crisis left unresolved create massive unemployment upend governments unfortunately breed instability ... appreciated putting context threat matrix look pakistan country know stabilized benefit south asia beyond june 2013 pakistan armed forces started joint-war game exercise codenamed azm-i-nau iv aim update military readiness strategy dealing complex security threat environment objective exercise assess military tactics procedures techniques event emerging threat environment explore joint operations strategies response combating threat three branches military army air force navy exercise took place amid renewed fears situation afghanistan post-withdrawal coalition forces 2014 well continuing internal threat terrorism india growing regional ambitions newspaper dawn reported senior military official said war games meant coming comprehensive response threats explained threat matrix evolving transforming includes internal challenge terror groups various shades conventional threat external aggression 2009 azm-i-nau exercises aimed preempting india cold start doctrine improving joint armed forces response conventional threat work published dr. farrukh saleem current threat matrix five major elements military nuclear terrorism cyber economic according saleem first two threats military nuclear existential nature threaten basis state physical existence existential threats essentially threaten unity demography integrity nation-state pakistan last three threats terrorism cyber economic non-existential nature asymmetric sense belligerents possess unequal military resources weaker opponent uses unconventional weapons tactics exploit vulnerabilities enemy government military science officials describing threat matrix program legally morally sound recent joint military exercises conducted rapidly respond threat matrix falls category low-intensity conflict confronted areas country soon revelation program international media ispr international media quoted change policy seen paradigm shift country policy however pakistani political science scholar ghazi salahuddin remains uncertain described paradigm shift
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Databases
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hybrid array hybrid array form hierarchical storage management combines hard disk drives hdds solid-state drives ssds i/o speed improvements hybrid storage arrays aim mitigate ever increasing price-performance gap hdds dram adding non-volatile flash level memory hierarchy hybrid arrays thus aim lower cost per i/o compared using ssds storage hybrid architectures simple involving single ssd cache desktop laptop computers complex configurations data centers cloud computing commercial products building hybrid arrays include
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Operating systems
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sticky notes sticky notes desktop notes application included windows 7 windows 8 windows 10 present windows vista gadget windows sidebar originated windows xp tablet edition 2002 program allows users take notes using post-it note–like windows desktop according microsoft employee eight million monthly sticky notes users april 2016 original sticky notes gadget one many included vista although gadgets continued windows 7 sticky notes removed list made standalone app built win32 platform could still open startup version directly support pen input default color yellow five colors offered sticky notes jumplists taskbar preview shows notes stack sticky notes automatically saved version reused windows 8 initial releases windows 10 windows 10 anniversary update new version built universal windows platform introduced launched standalone app part windows ink workspace latter method causes space behind notes become blurred new version directly accepts pen input recognize words letters handwritten text new sticky notes provides stock information ticker typed written provides flight info flight number typed written cortana integration create reminders notes include date unlike windows 7 version version taskbar preview shows stock image rather notes user created originally jump list added back version 1.6.2 february 6 2017 sticky notes sync notes across multiple devices windows 10 also ios android devices running microsoft onenote web client edit sticky notes also available onenote website obscure codice_1 location
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Operating systems
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l4 microkernel family l4 family second-generation microkernels generally used implement unix-like operating systems also used variety systems l4 like predecessor l3 microkernel created german computer scientist jochen liedtke response poor performance earlier microkernel-based operating systems liedtke felt system designed start high performance rather goals could produce microkernel practical use original implementation hand-coded intel i386-specific assembly language code 1993 sparked intense interest computer industry since introduction l4 developed platform independence also improving security isolation robustness various re-implementations original binary l4 kernel interface abi successors including l4ka :pistachio uni karlsruhe l4/mips unsw fiasco tu dresden wrmos wrmlab reason name l4 generalized longer refers liedtke original implementation applies whole microkernel family including l4 kernel interface different versions l4 widely deployed one variant okl4 open kernel labs shipped billions mobile devices specifying general idea microkernel liedtke states concept tolerated inside microkernel moving outside kernel i.e. permitting competing implementations would prevent implementation system required functionality spirit l4 microkernel provides basic mechanisms address spaces abstracting page tables providing memory protection threads scheduling abstracting execution providing temporal protection inter-process communication controlled communication across isolation boundaries operating system based microkernel like l4 provides services servers user space monolithic kernels like linux older generation microkernels include internally example order implement secure unix-like system servers must provide rights management mach included inside kernel poor performance first-generation microkernels mach led number developers re-examine entire microkernel concept mid-1990s asynchronous in-kernel-buffering process communication concept used mach turned one main reasons poor performance induced developers mach-based operating systems move time-critical components like file systems drivers back inside kernel somewhat ameliorated performance issues plainly violates minimality concept true microkernel squanders major advantages detailed analysis mach bottleneck indicated among things working set large ipc code expresses poor spatial locality results many cache misses in-kernel analysis gave rise principle efficient microkernel small enough majority performance-critical code fits first-level cache preferably small fraction said cache jochen liedtke set prove well designed thinner ipc layer careful attention performance machine-specific opposed platform independent design could yield massive real-world performance improvements instead mach complex ipc system l3 microkernel simply passed message without additional overhead defining implementing required security policies considered duties user space servers role kernel provide necessary mechanism enable user-level servers enforce policies l3 developed 1988 proved safe robust operating system used many years example tüv süd experience using l3 liedtke came conclusion several mach concepts also misplaced simplifying microkernel concepts even developed first l4 kernel primarily designed high performance mind order wring every bit performance entire kernel written assembly language ipc 20 times faster mach dramatic performance increases rare event operating systems liedtke work triggered new l4 implementations work l4-based systems number universities research institutes including ibm liedtke started work 1996 tu dresden unsw ibm thomas j. watson research center liedtke colleagues continued research l4 microkernel based systems general especially sawmill os 1999 liedtke took systems architecture group university karlsruhe continued research microkernel systems proof concept high performance microkernel could also constructed higher level language group developed l4ka :hazelnut c++ version kernel ran ia-32- arm-based machines effort success — performance still acceptable — release pure assembly language versions kernels effectively discontinued parallel development l4ka :hazelnut 1998 operating systems group tud os tu dresden dresden university technology started develop c++ implementation l4 kernel interface called l4/fiasco contrast l4ka :hazelnut allow concurrency kernel successor l4ka :pistachio allows interrupts kernel specific preemption points l4/fiasco fully preemptible exception extremely short atomic operations achieve low interrupt latency considered necessary l4/fiasco used basis drops hard real-time capable operating system also developed tu dresden however complexities fully preemptible design prompted later versions fiasco return traditional l4 approach running kernel interrupts disabled except limited number preemption points release l4ka :pistachio newer versions fiasco l4 microkernels inherently tied close underlying cpu architecture next big shift l4 development development platform-independent api still retained high performance characteristics despite higher level portability although underlying concepts kernel new api provided many significant changes relative previous l4 versions including better support multi-processor systems looser ties threads address spaces introduction user-level thread control blocks utcbs virtual registers releasing new l4 api version x.2 a.k.a version 4 early 2001 system architecture group university karlsruhe implemented new kernel l4ka :pistachio completely scratch focus high performance well portability released two-clause bsd license l4/fiasco microkernel also extensively improved years supports several hardware platforms ranging x86 amd64 several arm platforms notably version fiasco fiasco-ux run user-level application top linux l4/fiasco implements several extensions l4v2 api exception ipc enables kernel send cpu exceptions user-level handler applications help alien threads possible perform fine-grained control system calls x.2-style utcbs added furthermore fiasco contains mechanisms controlling communication rights well kernel-level resource consumption top fiasco collection basic user level services developed called l4env amongst others used para-virtualise current linux version 4.19 may 2019 called l4linux development also took place university new south wales unsw developers implemented l4 several 64-bit platforms work resulted l4/mips l4/alpha resulting liedtke original version retrospectively named l4/x86 like liedtke original kernels unsw kernels written mixture assembly c unportable implemented scratch release highly portable l4ka :pistachio unsw group abandoned kernels favor producing highly tuned ports l4ka :pistachio including fastest-ever reported implementation message passing 36 cycles itanium architecture group also demonstrated user-level device drivers perform well in-kernel drivers developed wombat highly portable version linux l4 runs x86 arm mips processors xscale processors wombat demonstrates context-switching costs 50 times lower native linux later unsw group new home nicta forked l4ka :pistachio new l4 version called nicta :l4-embedded name implies aimed use commercial embedded systems consequently implementation trade-offs favored small memory footprints aimed reduce complexity api modified keep almost system calls short enough need preemption points ensure high real-time responsiveness november 2005 nicta announced qualcomm deploying nicta l4 version mobile station modem chipsets led use l4 mobile phone handsets sale late 2006 august 2006 ertos leader unsw professor gernot heiser spun company called open kernel labs ok labs support commercial l4 users develop l4 commercial use brand name okl4 close collaboration nicta okl4 version 2.1 released april 2008 first generally available version l4 featured capability-based security okl4 3.0 released october 2008 last open-source version okl4 recent versions closed source based rewrite support native hypervisor variant called okl4 microvisor ok labs also distributed paravirtualized linux called ok linux descendant wombat well paravirtualized versions symbianos android ok labs also acquired rights sel4 nicta okl4 shipments exceeded 1.5 billion early 2012 mostly qualcomm wireless modem chips deployments include automotive infotainment systems apple mobile application processors beginning a7 contain secure enclave coprocessor running l4 operating system based l4-embedded kernel developed nicta 2006 implies l4 shipping ios devices total shipment estimated 310 million year 2015 2006 nicta group commenced from-scratch design third-generation microkernel called sel4 aim providing basis highly secure reliable systems suitable satisfying security requirements common criteria beyond beginning development aimed formal verification kernel ease meeting sometimes conflicting requirements performance verification team used middle-out software process starting executable specification written haskell sel4 uses capability-based access control enable formal reasoning object accessibility formal proof functional correctness completed 2009 proof provides guarantee kernel implementation correct specification implies free implementation bugs deadlocks livelocks buffer overflows arithmetic exceptions use uninitialised variables sel4 claimed first-ever general-purpose operating-system kernel verified sel4 takes novel approach kernel resource management exporting management kernel resources user level subjects capability-based access control user resources model also adopted barrelfish simplifies reasoning isolation properties enabler later proofs sel4 enforces core security properties integrity confidentiality nicta team also proved correctness translation c executable machine code taking compiler trusted computing base sel4 implies high-level security proofs hold kernel executable sel4 also first published protected-mode os kernel complete sound worst-case execution-time wcet analysis prerequisite use hard real-time systems 29 july 2014 nicta general dynamics c4 systems announced sel4 end end proofs released open-source licenses kernel source proofs gplv2 libraries tools 2-clause bsd license researchers state cost formal software verification lower cost engineering traditional high-assurance software despite providing much reliable results specifically cost one line code development sel4 estimated around compared traditional high-assurance systems darpa high-assurance cyber military systems hacms program nicta together project partners rockwell collins galois inc university minnesota boeing developed high-assurance drone based sel4 along assurance tools software planned technology transfer onto optionally piloted autonomous unmanned little bird helicopter development boeing final demonstration hacms technology took place sterling va april 2017 darpa also funded several small business innovative research sbir contracts related sel4 program started dr. john launchbury small businesses receiving sel4-related sbir included dornerworks techshot wearable inc real time innovations critical technologies osker os written haskell targeted l4 specification although project focused use functional programming language os development microkernel research per se codezero l4 microkernel targeting embedded systems focus virtualization implementation native os services gpl-licensed version version relicensed developers closed source forked 2010 f9 microkernel bsd-licensed l4 implementation built scratch deeply embedded devices performance arm cortex-m3/m4 processors power consumption memory protection mind fiasco.oc third generation microkernel evolved predecessor l4/fiasco fiasco.oc capability based supports multi-core systems hardware assisted virtualization completely redesigned user-land environment running top fiasco.oc called l4 runtime environment l4re provides framework build multi-component systems including client/server communication framework common service functionality virtual file-system infrastructure popular libraries c library libstdc++ pthreads platform also offers l4linux multi-architecture virtualized linux system l4re fiasco.oc run x86 ia-32 amd64 arm powerpc wip supersede previous system l4env l4/fiasco nova os virtualization architecture research project focus constructing secure efficient virtualization environment small trusted computing base nova consists microhypervisor user level virtual-machine monitor unprivileged componentised multi-server user environment running top called nul nova runs x86-based multi-core systems wrmos open source real time operating system rtos based l4 microkernel implementations kernel standard libraries network stack following architectures supported sparc arm x86 x86_64 wrmos kernel based l4 kernel reference manual version x.2 paravirtualized linux kernel w4linux working top wrmos
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Computer architecture
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webalizer webalizer web log analysis software generates web pages analysis access usage logs one commonly used web server administration tools initiated bradford l. barrett 1997 statistics commonly reported webalizer include hits visits referrers visitors countries amount data downloaded statistics viewed graphically presented different time frames day hour month website traffic analysis produced grouping aggregating various data items captured web server form log files website visitor browsing website webalizer analyzes web server log files extracting items client ip addresses url paths processing times user agents referrers etc grouping order produce html reports web servers log http traffic using different file formats common file formats common log format clf apache custom log format extended log file format example clf log line shown apache custom log format customized log http parameters including request processing time size request format custom log controlled format line typical apache log format configuration shown microsoft internet information services iis web server logs http traffic w3c extended log file format similarly apache custom log format iis logs may configured capture extended parameters request processing time w3c extended logs may recognized presence one format lines one shown webalizer process clf apache w3c extended log files well http proxy log files produced squid servers log file formats usually converted clf order analyzed addition logs compressed either gzip .gz bzip2 .bz2 processed directly without need uncompress use webalizer command line application launched operating system shell prompt typical command shown command instructs webalizer analyze log file access_log run incremental mode -p interpret log clf log file -f use domain name en.wikipedia.org report links -n produce output subdirectory current directory use -h option see complete list command line options besides command line options webalizer may configured parameters configuration file default webalizer reads file webalizer.conf interprets line processing instruction alternatively user-specified file may provided using -c option example webmaster would like ignore requests made particular group hosts use ignoresite parameter discard log records ip address matching specified pattern one hundred available configuration parameters make webalizer highly configurable web traffic analysis application complete list configuration parameters please refer readme file shipped every source binary distribution default webalizer produces two kinds reports yearly summary report detailed monthly report one analyzed month yearly summary report provides information number hits file page requests hosts visits well daily averages counters month report accompanied yearly summary graph monthly reports generated single html page containing monthly summary report listing overall number hits file page requests visits hosts etc daily report grouping counters days month aggregated hourly report grouping counters hour day together url report grouping collected information url host report ip address website entry exit url reports showing common first last visit urls referrer report grouping referring third-party urls leading analyzed website search string report grouping items search terms used search engines google user agent report grouping browser type country report grouping host country origin standard html reports described lists top entries item e.g top 20 urls actual number lines reports controlled configuration webalizer may also configured produce separate report items list every single item website visitors requested urls etc addition html reports webalizer may configured produce comma-delimited dump files list report data plain-text file dump files may imported spreadsheet applications databases analysis html reports may produced reports 30 languages including catalan croatian czech danish dutch english estonian finnish french galician german greek hungarian icelandic indonesian italian japanese korean latvian malay norwegian polish portuguese portuguese brazil romanian russian serbian simplified chinese slovak slovene spanish swedish turkish ukrainian generate reports alternate language requires separate webalizer binary compiled specifically language
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Web technology
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.htaccess .htaccess hypertext access file directory-level configuration file supported several web servers used configuration website-access issues url redirection url shortening access control different web pages files 'dot period full stop file name makes hidden file unix-based environments site could one .htaccess file files placed inside web tree i.e inside directories sub-directories hence name distributed configuration files .htaccess files act subset server global configuration file like httpd.conf directory sub-directories original purpose .htaccess—reflected name—was allow per-directory access control example requiring password access world wide web content commonly however .htaccess files define override many configuration settings content type character set common gateway interface handlers etc .htaccess files written apache directives variant perl compatible regular expressions pcre language learning basic pcre help mastering work files historical reasons format .htaccess files limited subset apache http server global configuration file httpd.conf even used web servers oracle iplanet web server zeus web server different native global configuration files controlling apache using main server configuration file httpd.conf often preferred security performance reasons
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Web technology
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internet content adaptation protocol internet content adaptation protocol icap lightweight http-like protocol specified rfc 3507 used extend transparent proxy servers thereby freeing resources standardizing way new features implemented icap generally used implement virus scanning content filters transparent http proxy caches content adaptation refers performing particular value added service content manipulation associated client request/response icap concentrates leveraging edge-based devices caching proxies help deliver value-added services core process cache proxy client transactions process web servers icap servers focused specific function example ad insertion virus scanning multi-av scanning opswat content translation language translation content filtering off-loading value-added services web servers icap servers allows web servers scaled according raw http throughput versus handle extra tasks icap proposed late 1999 peter danzig john schuster network appliance gillies took project spring 2000 enhanced protocol three main ways gillies prototyped first icap client server netcache series internet caches mid-2000 known icap 0.9 protocol produced training materials vendors client written c++ core netcache server demonstration icap server written perl employed debian word-replacement filters rewrite web pages skipping html tags translating web pages swedish chef jive real time knowledge learned prototyping experience gillies revised ietf draft standard make rpcs using chunked encoding greatly simplifying icap protocol
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Internet protocols
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package format package format type archive containing computer programs additional metadata needed package managers archive file format may unchanged package formats bear additional metadata manifest file certain directory layouts packages may contain either source code executable files packages may converted one type another software alien arch linux pacman slackware use tar archives generic naming specific internal structures
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Operating systems
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dos xl dos xl discontinued disk operating system dos written paul laughton mark rose bill wilkinson mike peters published optimized systems software atari 8-bit family home computers designed compatible atari dos came shipped atari inc. disk drives direct descendant os/a+ dos xl provided additional features atari equipped floppy disk drives included single double density support command-line mode called command processor cp menu mode executable loaded memory batch file support support xl extended memory oss supercartridge banked memory later versions included axlon ramdisk support mosaic ramdisk support bit-3 support bug/65 addition supporting auto-booting codice_1 files dos xl batch features provided auto-booting batch feature naming batch file codice_2 would execute batch commands startup os/a+ unfortunately feature n't compatible programs e.g atariwriter dos xl distributed flippy disk one side single-density version double-density version features add-ons included placed double-density side due lack disk space manual dos xl subset os/a+ oss considered manual addendum os/a+ 150+ pages bound spine loose-leaf form like os/a+ manual dos xl came two versions 2.20 2.30 2.20 users pay 20 upgrade 2.30 last version 2.30p dos xl originally sold 30 price later increased 39 file writing verify turned dos xl due oss experience resulted faster writes virtually risk errors command file verify.com included reenable writes verify atari dos 2.0s default verified file writes disk several disk drive manufacturers shipped dos xl drives trak percom astra indus amdek rana c copy files p protect files version 2.30p newer version 2.30 fix two problems patch dos xl 2.30 make 2.30p plans dos xl 4 scrapped due low demand competition oss reissued os/a+ 4.1 mainly double-sided support dos xl along oss products became part icd catalog atari products january 1988 however dos xl dropped favor icd spartados
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Operating systems
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comparison multi-paradigm programming languages programming languages grouped number types paradigms supported concise reference programming paradigms listed article
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Programming language topics
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cloudbook cloudbook discontinued x86 subnotebook ultra-mobile pc developed everex using via processor chipset nanobook reference design competed asus eee pc olpc xo-1 classmate pc device categorized netbook around 2008 term cloudbook resurrected refer small-storage laptops depend networked storage services cloud come packaged device google chrome os cloudbooks chromebooks installed google drive windows os cloudbooks bundled microsoft onedrive sales gpc tc2502 everex desktop left company inquiries customers seeking similar additional open source mobile platforms everex decided build two systems classic laptop also running gos v2 called gbook system based via nanobook reference design also used packard bell easynote xs release originally planned january 25 2008 everex pushed release back citing problems version gos wanted use delay needed everex wanted rewrite gos v2 cloudbook would use gnome window manager instead enlightenment 17 making even compatible ubuntu e17 dock replaced avant window navigator approach looks functionality older gos versions cloudbook expected released united states february 15 2008 wal-mart zareason pushed back february 21 wal-mart zareason received part shipment price device set us 399 came one year limited warranty 24/7 toll free technical support nivio also created cloudbook based nokia/intel meego platform owned us trademark cloudbook cloudpc aiming use linux platform delivering full windows experience desktop service appstore renting software launched airtel india nivio co-founded sachin dev duggal saurabh p dhoot everex cloudbook uniquely located built-in pointing device stamp-sized touchpad upper right side computer instead bottom keyboard common notebook computers cloudbook intended held one hand typing two hands using mouse-cursor control left thumb controlling two mouse buttons right thumb small trackpad mousepad keys placed directly screen design chosen system could even used standing walking around instead sitting cloudbook sold ultra-mobile pc umpc feature even though touch-screen cloudbook came completely new version compared version used gpc gos linux distribution based ubuntu application software mozilla skype facebook faqly openoffice.org google originally gos came enlightenment 0.17 window manager though pre-installed operating system gos everex released windows xp hardware drivers making simple install microsoft windows xp however everex warns software outside original gos covered warranty though hardware warranty unaffected next generation cloudbook advertised processor running 1.6 ghz 80gb disk drive touch pad wimax however company ceased operations
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Distributed computing architecture
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department defense information assurance certification accreditation process dod information assurance certification accreditation process diacap united states department defense dod process means ensure companies organizations apply risk management information systems diacap defines dod-wide formal standard set activities general tasks management structure process certification accreditation c dod maintains information assurance ia posture throughout system life cycle note march 12 2014 though official transition take place may 2015 diacap replaced risk management framework rmf dod information technology although re-accreditations continue late 2016 systems yet started accreditation may 2015 transition rmf processes dod rmf aligns national institute standards technology nist risk management framework rmf diacap resulted nsa directed shift underlying security approaches interim version diacap signed july 6 2006 superseded interim ditscap guidance final version called department defense instruction 8510.01 signed march 12 2014 previous version november 28 2007 dodi 8500.01 cybersecurity http //www.dtic.mil/whs/directives/corres/pdf/850001_2014.pdf dodi 8510.01 risk management framework rmf dod information technology http //www.dtic.mil/whs/directives/corres/pdf/851001_2014.pdf diacap differs ditscap several ways—in particular embrace idea information assurance controls defined dodd 8500.1 dodi 8500.2 primary set security requirements automated information systems aiss ia controls determined based system mission assurance category mac confidentiality level cl
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Computer security
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federico heinz federico heinz argentinian programmer free software advocate living london co-founder current president fundación vía libre non-profit organization promotes free flow knowledge motor social progress use development free software helped legislators argentina ing dragan dr. conde peru dr. villanueva draft defend legislation demanding use free software areas public administration works google uk office speaks fluent spanish english german
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Operating systems
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cyber essentials cyber essentials uk government information assurance scheme operated national cyber security centre ncsc encourages organisations adopt good practice information security includes assurance framework simple set security controls protect information threats coming internet developed collaboration industry partners including information security forum isf information assurance small medium enterprises consortium iasme british standards institution bsi endorsed uk government launched 2014 department business innovation skills organisations earn two levels certification badges annual recertification recommended certifying bodies turn licensed accreditation bodies appointed uk government five current accreditation bodies apmg crest iasme irm security qg council registered ethical security testers crest developed assessment framework iasme incorporated cyber essentials wider iasme information assurance standard iso/iec 27001 organisations may choose limit scope certification certain subset business five main technical controls cyber essentials guidance breaks finer details controls mapped controls required iso/iec 27001 standard good practice iasme governance although cyber essentials narrower focus emphasising technical controls rather governance risk policy cyber essentials scheme launched 5 june 2014 several organisations quickly certified end june since october 2014 cyber essentials certification required suppliers central uk government handle certain kinds sensitive personal information intended encourage adoption businesses wishing bid government contracts insurers suggested certified bodies may attract lower insurance premiums 6,000 cyber essentials certificates awarded businesses organisations wannacry ransomware attack nhs digital refused finance £1 billion estimated cost meeting cyber essentials plus standard saying would constitute value money invested £60 million planned plan spend £150 million address key cyber security weaknesses next two years
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Computer security
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miva script miva script proprietary computer scripting language mainly used internet applications e-commerce 2015 developed maintained owned miva merchant inc. based san diego california many web hosting companies support miva script servers significantly less widespread popular web languages language first developed name htmlscript joe austin others 1995 company htmlscript corporation formed following year origins miva script began 1993 david haldy joseph austin built first version htmlscript first version written programming language perl called logic enhanced html lehtml joseph austin wrote wrapper programming language c let start root process downgrade immediately ownership permissions owner script file wrapper made suitable use hosting service called volant turnpike time joseph austin eventually sold volant turnpike dave haldy perl allowed self-executing code lehtml expression analyzer parsed expression perl syntax passed perl volant turnpike users liked using lehtml joseph austin ron ahern wrote expression analyzer re-implemented lehtml syntax c language joseph austin called end result htmlscript registered name united states patent trademark office uspto joseph austin troy mccasland derek finley founders company called htmlscript corporation htmlscript concept loop low server processing power time would enough bring whole server even one program ran away joseph austin implement loop make impossible htmlscript server process run away also implemented macro first version htmlscript would allow self-executing code macro powerful eventually security issues 1997 jon burchmore extensively rewrote language make syntactically consistent although new engine supported old htmlscript new named mivascript syntaxes jon burchmore rewrote htmlscript syntax joe developed help softquad using emerging xml standard jon burchmore wrote replacement koolkat became miva merchant new end-product supported old htmlscript syntax new named miva script syntaxes october 14 1997 htmlscript ’ name changed miva script company name changed miva soon afterward miva merchant followed suit name product name miva comes egyptian hieroglyphics word cat word cat combination two symbols milk basin followed quail milk basin pronounced mee quail pronounced waa combined say cat joseph austin thought clever called koolkat “ electronic cat alog. ” joseph showed german friend could pronounce waa sound instead kept pronouncing va joseph austin registered domain miva.com filed trademark 1998 firm renamed miva corporation 1998 first version miva merchant came 2002 miva script compiler delivered htmlscript syntax macros dropped engine miva corporation sold 2003 mid-cap public company called findwhat subsequently findwhat bought name miva 2007 russell carroll group investors bought original miva technologies customer base miva started miva merchant inc. miva script often described 'xml-like although something misnomer consists tags may interspersed html xhtml start mv paired stand-alone empty tags version 4.14 miva script interpreted miva script engine empresa version 4.00 introduced compiler boosting performance significantly one distinguishing features miva script native support variation dbase database platform dbf iii tables proprietary index format support sql many installations today running mysql database variables untyped pre-declared miva script uses file extensions .mv .mvc .mvt common file extension runtime compiled template source files empresa underlying engine miva script versions numbered less 4.0 miva merchant empresa script interpreter available web servers running *nix microsoft windows operating systems recent interpreter version 3.9705 interpreted miva script still widely supported many web hosts versions numbered 3.9x transitional form language implementing new features found version 4 arrays since 4.0 miva merchant empresa virtual machine running compiled miva script available versions *nix microsoft windows current version level 5.x added new language constructs native sql support new access-methodology dbase3 tables called miva-sql new templating syntax empresa virtual machine compile fly version 5.08 later support gd graphics library miva merchant mia version empresa engine designed run windows pc localhost server watching specified port usually 8000 8080 server software needed unless post office protocol pop smtp functions used provides portable stand-alone development environment miva merchant mia updated miva merchant empresa release like empressa versions pre-4 interpreters post-4.0 work compiled script minor differences miva merchant script compiler introduced mid-2002 claiming offer better performance closure application source code compilability required changes language support old htmlscript syntax macros evaluated runtime often considered security risk dropped compiler produces platform-independent bytecode runs miva merchant empresa miva merchant mia virtual machines minor variations exist empresa mia virtual machines may 2005 miva corporation made script compiler available free 2011 built licensing code removed simplifying installation august 2007 miva merchant separated parent company due management buy-out ref press release miva script 5.0 introduced page template compiler command basis miva merchant storemorph trade page template system compiler within compiler offers simplified subset full language suitable end user creation editing web page templates storemorph trade pages allow modular components created mivascript added template extending capabilities february 2011 introduced new mivascript.com website fully documenting latest version language including gd graphics library
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Programming language topics
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laim working group laim log anonymization information management working group nsf onr funded research group national center supercomputing applications direction adam slagell work group focuses upon log anonymization internet privacy laim group established 2005 released 3 different log anonymization tools canine scrub-pa flaim flaim tool still active development
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Computer security
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daniel balsam daniel balsam american lawyer best known lawsuits e-mail spammers violations internet spam laws balsam filing lawsuits spammers since 2002 earned 1 million court judgments filing lawsuits balsam aims publicize names principals profiting spam advertising aims make spamming less profitable cause companies reconsider decision market products spam balsam describes practice cleaning internet although critics accuse taking advantage legal system balsam decided begin suing spammers became enraged volume breast enlargement spam received working marketing began filing lawsuits small claims court 2002 initially seeing lawsuits hobby balsam soon decided make vocation attended university california hastings college law graduated 2008 time graduated law school balsam filed several dozen lawsuits files lawsuits based spam receives e-mail addresses makes enough money court judgments support full-time help attorney timothy walton judgments 1,000 per e-mail spam messages identify company sending message often difficult identify source balsam frequently faced fictitious business names registered post office boxes balsam awarded 1.125 million verdict pornography company sent 1,125 e-mails able collect judgment however domain registrar tucows refused identify owner company sent spam balsam lawsuits brought california anti-spam laws although many cases tried small claims court filed first spam lawsuit brought trial california superior court— balsam v. trancos inc. —which currently appeal among companies balsam sued small claims court various inc. dba adult friendfinder tagged.com deniro marketing llc dba amateurmatch stockton asparagus festival balsam critical can-spam act arguing tough enough spammers also believes u.s. government enough enforce laws spam still law school balsam helped draft bill ab 2950 sponsored california state assemblyman jared huffman would toughened california anti-spam laws bill aimed close proponents characterized loopholes tighten ambiguous language business professions code 17529.5 clearly set forth practices unlawful make easier bring lawsuits deceptive spammers spamvertisers although bill passed state assembly governor arnold schwarzenegger vetoed bennet kelley internet lawyer balsam faced court vocally critical balsam tactics balsam also sued valueclick inc. twice bloosky interactive llc allegedly violating settlement confidentiality and/or non-disparagement agreements shortly entering settlement balsam maintains suits retaliatory
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Computer security
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bracket computing bracket computing cloud computing company founded 2011 tom gillis jason lango previously ironport systems based mountain view california 2015 company raised 45 million investment round led fidelity goldman sachs bringing funding total 130 million primary software offering called computing cell october 2015 company employed 70 people planned hire software engineers 1 may 2018 vmware announced tom gillis lead vmware network security business unit vmware intends acquire bracket computing intellectual property members bracket staff bracket computing website redirects 403 forbidden page
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Distributed computing architecture
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mandatory integrity control context microsoft windows family operating systems mandatory integrity control mic core security feature introduced windows vista implemented subsequent desktop line windows operating systems adds integrity levels il -based isolation running processes il represents level trustworthiness object mechanism goal use pre-existing integrity control policies involved objects il selectively restrict access permissions contexts considered potentially less trustworthy compared contexts running user account trusted mandatory integrity control defined using new access control entry ace type represent object il security descriptor windows access control lists acls used grant access rights read write execute permissions privileges users groups il assigned subject access token initialized subject tries access object example file security reference monitor compares integrity level subject access token integrity level object security descriptor windows restricts allowed access rights depending whether subject il higher lower object depending integrity policy flags new access control entry ace security subsystem implements integrity level mandatory label distinguish discretionary access user control acls provide windows vista defines four integrity levels low sid s-1-16-4096 medium sid s-1-16-8192 high sid s-1-16-12288 system sid s-1-16-16384 default processes started regular user gain medium il elevated processes high il introducing integrity levels mic allows classes applications isolated enabling scenarios like sandboxing potentially-vulnerable applications internet-facing applications processes low il called low-integrity processes less access processes higher ils access control enforcement windows objects access control lists named objects including files registry keys even processes threads entry system access control list governing access defines minimum integrity level process use object windows makes sure process write delete object integrity level equal higher requested integrity level specified object additionally privacy reasons process objects higher il out-of-bounds even read access processes lower il consequently process interact another process higher il process perform functions inject dll higher il process using codice_1 api function send data different process using codice_2 function processes inherit integrity level process spawned integrity level customized time process creation well defining boundary window messages user interface privilege isolation uipi technology mandatory integrity control used applications like adobe reader google chrome internet explorer windows explorer isolate documents vulnerable objects system internet explorer 7 introduces mic-based protected mode setting control whether web page opened low-integrity process provided operating system supports mic based security zone settings thereby preventing classes security vulnerabilities since internet explorer case runs low il process modify system level objects—file registry operations instead virtualized adobe reader 10 google chrome two notable applications introducing technology order reduce vulnerability malware microsoft office 2010 introduced protected view isolated sandbox environment excel powerpoint word prohibits potentially unsafe documents modifying components files resources system protected view operates low-integrity process windows vista later versions windows uses mic uipi restrict sandbox however cases higher il process need execute certain functions lower il process lower il process need access resources higher il process access example viewing webpage protected mode save file downloaded internet folder specified user high il low il processes still communicate using files named pipes lpc shared objects shared object must integrity level low low il process shared low il high il processes since mic prevent low il process sharing objects higher il process trigger flaws higher il process work behalf low il process thereby causing squatting attack shatter attacks however prevented using user interface privilege isolation takes advantage mic
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Operating systems
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devices profile web services devices profile web services dpws defines minimal set implementation constraints enable secure web service messaging discovery description eventing resource-constrained devices objectives similar universal plug play upnp addition dpws fully aligned web services technology includes numerous extension points allowing seamless integration device-provided services enterprise-wide application scenarios dpws specification initially published may 2004 submitted standardization oasis july 2008 dpws 1.1 approved oasis standard together ws-discovery 1.1 soap-over-udp 1.1 june 30 2009 dpws defines architecture devices run two types services hosting services hosted services hosting services directly associated device play important part device discovery process hosted services mostly functional depend hosting device discovery addition hosted services dpws specifies set built-in services dpws builds following core web services standards wsdl 1.1 xml schema soap 1.2 ws-addressing comprises ws-metadataexchange ws-transfer ws-policy ws-security ws-discovery ws-eventing microsoft windows vista windows embedded ce6r2 platforms natively integrate dpws stack called wsdapi included part windows rally technologies support osgi way dpws supports dynamic discovery part evolving vision distributed applications leverage ws-* standards application automation environments clear 2007 consumer electronics show “ next gen ” home highlighted automation system life|ware exceptional innovation uses dpws communicate lighting system audio distribution system security system motorized shades security cameras thermostats washers dryers motorized television mount show demonstrated tremendous consumer interest prospect bringing controllable devices environment digital entertainment manufacturers taking notice many manufacturers first step towards dpws adoption creation small “ device bridge ” native usually proprietary code web services least 117 automation av products 37 different vendors currently support dpws either natively bridge international security controls isc trade show major security company demonstrated security system supported dpws kitchen bath show kbis saw two major appliance manufacturers demonstrating washers dryers communicated using dpws communicative oven demonstrated international building show past two years even greater sign drive towards market acceptance dpws introduced-in-2006 connectedlife.home home automation package offered us retailer best buy package uses automation software controllable devices leverage dpws communications within sirena project auspices european research initiative itea schneider electric produced early dpws implementation targeted embedded devices implementation open-sourced soa4d.org soa devices website dpws stack c java versions add-ons like ws-management ws-security implementations freely downloaded also stemming sirena project web services devices ws4d.org website provides information downloads news three dpws implementations one c implementation integrating gsoap one java implementation using axis another java implementation use different java editions including java following sirena project new european research project itea named soda service oriented device delivery architecture went development implementation embedded dpws stack devices associated tools eu research project socrades composed heavyweights like abb sap schneider electric siemens focusing implementing testing piloting prototypes dpws-enabled devices industrial automation domain extending work eu aesop project several proposals and/or projects worked integration dpws osgi i.e mainly providing implementation java framework
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Web technology
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xswitch xswitch interconnect used xcore processor interconnect protocol defined xmos based around routing messages comprising 9-bit tokens cores network protocol specifically designed on-chip board-level communication using lvds drivers also run longer cables interconnect routes sequences messages message consists header specifies core address sequence tokens end-token 512 tokens 256 data tokens 256 control tokens data tokens used transport data e.g audio data stream control tokens used send in-band control data order implement protocols interconnect message routed sequence switches interconnected xlinks two control tokens used end message end ends message pause suspends message tokens free route switches difference end pause end token delivered receiver whereas pause token silently thrown away last switch since messages terminated token rather packet length sender may choose terminate message creates open circuit guaranteed bandwidth latency applications use example one series links form circuit stream audio use another series links small packets containing control data circuits guarantee order delivery tokens transmitted messages may delivered order multiple paths circuits permanently occupy series links whereas messages occupy links short periods time xswitch interconnect architecture implements media layer osi model physical layer signal either transmitted using serial protocol two wires using fast protocol five wires cases signal transmitted series transitions using 1 code two-wire system transition wire 0 signals 0 bit transition wire 1 signals 1 bit token transmitted sequence exactly 10 transitions first eight signal eight data bits msb first one bit signal whether control token finally return-to-zero bit returns wires zero nine transitions one wire high five-wire system four data wires 0 1 2 3 transition 0 signals '00 transition 1 signals '01 etc sequence four transitions transmits eight data bits fifth wire escape wire used transmit control tokens unlike two-wire system even number wires high token wires return zero end message modes degree asynchronous clock transitions signal data order transitions signal order bits transmitter must transmit data faster receiver interpret data must make sure sufficient gaps edges overtake pads data transmission suspended time link layer protocol relies use credits order signal whether data transmitted receivers always issue credits transmitter transmitter allowed send data link give 8 32 64 credits never issue 127 credits guarantees side always record credits using 7 bit counters conversely large numbers credits given link needs large receive buffers minimum size receive buffer 8 tokens 72 bits network layer routes messages interconnect nodes network identified means 16-bit address messages routed successively matching bits destination address every node message brought closer destination taking first non matching bit looking set links used destination message routed link route rolled end pause control token found given header precedes packet implements wormhole routing routing set deadlock free free starvation interconnects arbitrate incoming messages without locking link switches xcore xs1-g4 xcore xs1-l1 xcore-200 processors implementations xswitch implementations differ terms number internal external links supported xs1-g4 switch 32 links 16 links external links operate speed 400 mbits per second 16 links connected four cores four links per core internal links operate 3.2 gbits per second maximum throughput implementation xswitch 57.6 gbits per second 6.4 gbit per second external links 51.2 gbits per second internal links xs1-l1 switch 12 links eight links external links operate speed 400 mbits per second four links connected internally core internal links operate 3.2 gbits per second maximum throughput implementation xswitch 16 gbits per second 3.2 gbit per second external links 12.8 gbits per second internal links xcore200 switch 17 links eight input links links external links operate speed 400 mbits per second eight links internal connected cores four core internal links operate 4 gbits per second final link connected on-chip usb phy maximum throughput implementation xswitch 35.25 gbits per second 3.2 gbit per second external links 32 gbits per second internal links plus 0.05 gbit/s final internal link
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Internet protocols
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public key infrastructure public key infrastructure pki set roles policies hardware software procedures needed create manage distribute use store revoke digital certificates manage public-key encryption purpose pki facilitate secure electronic transfer information range network activities e-commerce internet banking confidential email required activities simple passwords inadequate authentication method rigorous proof required confirm identity parties involved communication validate information transferred cryptography pki arrangement binds public keys respective identities entities like people organizations binding established process registration issuance certificates certificate authority ca depending assurance level binding may carried automated process human supervision pki role assures valid correct registration called registration authority ra ra responsible accepting requests digital certificates authenticating entity making request microsoft pki registration authority usually called subordinate ca entity must uniquely identifiable within ca domain basis information entity third-party validation authority va provide entity information behalf ca x.509 standard defines commonly used format public key certificates public key cryptography cryptographic technique enables entities securely communicate insecure public network reliably verify identity entity via digital signatures public key infrastructure pki system creation storage distribution digital certificates used verify particular public key belongs certain entity pki creates digital certificates map public keys entities securely stores certificates central repository revokes needed pki consists broadly speaking traditionally three approaches getting trust certificate authorities cas web trust wot simple public key infrastructure spki primary role ca digitally sign publish public key bound given user done using ca private key trust user key relies one trust validity ca key ca third party separate user system called registration authority ra may may separate ca key-to-user binding established depending level assurance binding software human supervision term trusted third party ttp may also used certificate authority ca moreover pki often used synonym ca implementation model trust relationships ca trusted third party – trusted subject owner certificate party relying upon certificate according netcraft industry standard monitoring active transport layer security tls certificates states that- although global tls ecosystem competitive dominated handful major cas — three certificate authorities symantec comodo godaddy account three-quarters issued tls certificates public-facing web servers top spot held symantec verisign purchased symantec ever since survey began currently accounting third certificates illustrate effect differing methodologies amongst million busiest sites symantec issued 44 valid trusted certificates use — significantly overall market share approach involves server acts offline certificate authority within single sign-on system single sign-on server issue digital certificates client system never stores users execute programs etc temporary certificate common find solution variety x.509-based certificates alternative approach problem public authentication public key information web-of-trust scheme uses self-signed certificates third party attestations certificates singular term web trust imply existence single web trust common point trust rather one number potentially disjoint webs trust examples implementations approach pgp pretty good privacy gnupg implementation openpgp standardized specification pgp pgp implementations allow use e-mail digital signatures self-publication public key information relatively easy implement one web trust one benefits web trust pgp inter-operate pki ca fully trusted parties domain internal ca company willing guarantee certificates trusted introducer web trust completely trusted nature web trust trusting one certificate granting trust certificates web pki valuable standards practices control issuance certificates including pgp personally instituted web trust could significantly degrade trustworthiness enterprise domain implementation pki web trust concept first put forth pgp creator phil zimmermann 1992 manual pgp version 2.0 another alternative deal public authentication public key information simple public key infrastructure spki grew three independent efforts overcome complexities x.509 pgp web trust spki associate users persons since key trusted rather person spki use notion trust verifier also issuer called authorization loop spki terminology authorization integral design emerging approach pki use blockchain technology commonly associated modern cryptocurrency since blockchain technology aims provide distributed unalterable ledger information qualities considered highly suitable storage management public keys cryptocurrencies support storage different public key types ssh gpg rfc 2230 etc provides open source software directly supports pki openssh servers blockchain technology approximate proof work often underpinning confidence trust relying parties pki issues remain administrative conformance policy operational security software implementation quality certificate authority paradigm issues regardless underlying cryptographic methods algorithms employed pki seeks endow certificates trustworthy properties must also address issues list known blockchain-based pki developments pki occurred early 1970s british intelligence agency gchq james ellis clifford cocks others made important discoveries related encryption algorithms key distribution however developments gchq highly classified results work kept secret publicly acknowledged mid-1990s public disclosure secure key exchange asymmetric key algorithms 1976 diffie hellman rivest shamir adleman changed secure communications entirely development high-speed digital electronic communications internet predecessors need became evident ways users could securely communicate consequence ways users could sure actually interacting assorted cryptographic protocols invented analyzed within new cryptographic primitives could effectively used invention world wide web rapid spread need authentication secure communication became still acute commercial reasons alone e.g. e-commerce online access proprietary databases web browsers sufficient taher elgamal others netscape developed ssl protocol 'https web urls included key establishment server authentication prior v3 one-way pki structure thus created web users/sites wishing secure communications vendors entrepreneurs saw possibility large market started companies new projects existing companies began agitate legal recognition protection liability american bar association technology project published extensive analysis foreseeable legal aspects pki operations see aba digital signature guidelines shortly thereafter several u.s. states utah first 1995 jurisdictions throughout world began enact laws adopt regulations consumer groups raised questions privacy access liability considerations taken consideration jurisdictions others enacted laws regulations differed technical operational problems converting pki schemes successful commercial operation progress much slower pioneers imagined would first years 21st century underlying cryptographic engineering clearly easy deploy correctly operating procedures manual automatic easy correctly design even designed execute perfectly engineering required standards existed insufficient pki vendors found market quite market envisioned mid-1990s grown slowly somewhat different ways anticipated pkis solved problems expected several major vendors gone business acquired others pki success government implementations largest pki implementation date defense information systems agency disa pki infrastructure common access cards program pkis one type another several vendors many uses including providing public keys bindings user identities used argue purchasing certificates securing websites ssl securing software code signing costly venture small businesses however emergence free alternatives let encrypt changed presently symantec holds major share pki certificate market sold one third certificates issued globally 2013 http/2 latest version http protocol allows unsecured connections theory practice major browser companies made clear would support state-of-art protocol pki secured tls connection web browser implementation http/2 including edge microsoft chrome google firefox mozilla opera supports http/2 tls using alpn extension tls protocol would mean get speed benefits http/2 website owners would forced purchase ssl certificates controlled corporations symantec current web browsers carry pre-installed intermediary certificates issued signed certificate authority means browsers need carry large number different certificate providers increasing risk key compromise key known compromised could fixed revoking certificate compromise easily detectable huge security breach browsers issue security patch revoke intermediary certificates issued compromised root certificate authority practical security vulnerabilities x.509 certificates known cases keys stolen major certificate authority listed
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Computer security
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joseph wenger joseph numa wenger june 7 1901 – september 2 1970 rear-admiral united states navy served first deputy director armed forces security agency afsa later first vice director national security agency december 1952 november 1953 separate divisions afsa merged nsa wenger one leaders responsible development nsa native patterson louisiana wenger one architects centralized cryptology february 1942 navy power struggles led ousting laurance safford op-20-g two new sections headed wenger communications decryption translation john r. redman communications combat intelligence safford removed current intelligence support research role safford sidelined remainder war ultimately joseph rochefort wenger integral starting afsa armed forces security agency predecessor nsa world war ii suggested navy spend 2 million build 360 four wheel bombes break effective british monopoly bombe died 1970
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Computer security
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serial communication telecommunication data transmission serial communication process sending data one bit time sequentially communication channel computer bus contrast parallel communication several bits sent whole link several parallel channels serial communication used long-haul communication computer networks cost cable synchronization difficulties make parallel communication impractical serial computer buses becoming common even shorter distances improved signal integrity transmission speeds newer serial technologies begun outweigh parallel bus advantage simplicity need serializer deserializer serdes outstrip disadvantages clock skew interconnect density migration pci pci express example many serial communication systems originally designed transfer data relatively large distances sort data cable practically long-distance communication transmits data one bit time rather parallel reduces cost cable cables carry data serial cable computer ports plug usually referred specific name reduce confusion keyboard mouse cables ports almost invariably serial—such ps/2 port apple desktop bus usb cables carry digital video almost invariably serial—such coax cable plugged hd-sdi port webcam plugged usb port firewire port ethernet cable connecting ip camera power ethernet port fpd-link etc cables ports transmitting data one bit time include serial ata serial scsi ethernet cable plugged ethernet ports display data channel using previously reserved pins vga connector dvi port hdmi port many communication systems generally designed connect two integrated circuits printed circuit board connected signal traces board rather external cables integrated circuits expensive pins reduce number pins package many ics use serial bus transfer data speed important examples low-cost serial buses include rs-232 spi i²c dc-bus uni/o 1-wire pci express ic serial bus may typically implemented using multiplexer utilizes technique called multiplexing communication links across computers parts computers talk one another may either serial parallel parallel link transmits several streams data simultaneously along multiple channels e.g. wires printed circuit tracks optical fibers whereas serial link transmits single stream data although serial link may seem inferior parallel one since transmit less data per clock cycle often case serial links clocked considerably faster parallel links order achieve higher data rate several factors allow serial clocked higher rate many cases serial cheaper implement parallel many ics serial interfaces opposed parallel ones fewer pins therefore less expensive
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Internet protocols
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kylo web browser kylo discontinued open-source web browser developed hillcrest labs microsoft windows mac os x initially released 2010 browser features 10-foot user interface large fonts buttons make easy see across room making especially suitable use home theater pc connected directly high-definition television 2011 kylo ces consumer electronics show innovations awards honoree category online audio/video content may 15 2012 kylo released open source software terms mozilla public license
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Internet protocols
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principle least privilege information security computer science fields principle least privilege polp also known principle minimal privilege principle least authority requires particular abstraction layer computing environment every module process user program depending subject must able access information resources necessary legitimate purpose principle means giving user account process privileges essential perform intended function example user account sole purpose creating backups need install software hence rights run backup backup-related applications privileges installing new software blocked principle applies also personal computer user usually work normal user account opens privileged password protected account superuser situation absolutely demands applied users terms least user access least-privileged user account lua also used referring concept user accounts times run privileges possible also launch applications privileges possible principle least privilege widely recognized important design consideration enhancing protection data functionality faults fault tolerance malicious behavior computer security benefits principle include practice exist multiple competing definitions true least privilege program complexity increases exponential rate number potential issues rendering predictive approach impractical examples include values variables may process addresses need precise time things required object capability systems allow instance deferring granting single-use privilege time used currently closest practical approach eliminate privileges manually evaluated unnecessary resulting set privileges typically exceeds true minimum required privileges process another limitation granularity control operating environment privileges individual process practice rarely possible control process access memory processing time i/o device addresses modes precision needed facilitate precise set privileges process require original formulation jerome saltzer peter j. denning paper fault tolerant operating systems set broader perspective among four fundamental principles fault tolerance dynamic assignments privileges earlier discussed roger needham 1972 historically oldest instance least privilege probably source code login.c begins execution super-user permissions and—the instant longer necessary—dismisses via setuid non-zero argument demonstrated version 6 unix source code kernel always runs maximum privileges since operating system core hardware access one principal responsibilities operating system particularly multi-user operating system management hardware availability requests access running processes kernel crashes mechanisms maintains state also fail therefore even way cpu recover without hard reset security continues enforced operating system properly respond failure possible detect failure kernel execution either halted program counter resumed execution somewhere endless and—usually—non-functional loop would akin either experiencing amnesia kernel execution failure trapped closed maze always returns starting point closed loops execution picks crash loading running trojan code author trojan code usurp control processes principle least privilege forces code run lowest privilege/permission level possible means code resumes code execution-whether trojan simply code execution picking unexpected location—would ability perform malicious undesirable processes one method used accomplish implemented microprocessor hardware example intel x86 architecture manufacturer designed four ring 0 ring 3 running modes graduated degrees access-much like security clearance systems defence intelligence agencies implemented operating systems processes execute potential privilege set active privilege set privilege sets inherited parent determined semantics fork executable file performs privileged function—thereby technically constituting component tcb concomitantly termed trusted program trusted process—may also marked set privileges logical extension notions set user id set group id inheritance file privileges process determined semantics exec family system calls precise manner potential process privileges actual process privileges file privileges interact become complex practice least privilege practiced forcing process run privileges required task adherence model quite complex well error-prone trusted computer system evaluation criteria tcsec concept trusted computing base tcb minimization far stringent requirement applicable functionally strongest assurance classes viz b3 a1 evidentiarily different functionally identical least privilege often associated privilege bracketing assuming necessary privileges last possible moment dismissing soon longer strictly necessary therefore ostensibly reducing fallout erroneous code unintentionally exploits privilege merited least privilege also interpreted context distribution discretionary access control dac permissions example asserting giving user u read/write access file f violates least privilege u complete authorized tasks read permission
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Computer security
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justine tunney justine alexandra roberts tunney born c. 1985 software developer former occupy movement activist blogger like many former black hat hackers kevin mitnick tunney participated sides cybersecurity black hat white hat tunney case first computer hacker later life volunteer fixing security vulnerabilities open source software 1999 age 14 operating online name oogle tunney built rampage toolz 2.o exploiting security vulnerabilities aol sending spam tunney said rampage toolz popular third-party aol prog time ran ads site height dot-com boom earned hundreds dollars month teenager know tunney stated never heard google time similar name oogle coincidence tunney published screenshots rampage toolz oogle.net website source code tool statute limitations expired 2016 employee google tunney discovered open source projects github vulnerable security vulnerability discovered five months previously software library projects used called apache commons collections started raising pull requests github fix problems recruiting volunteers scale problem became apparent team volunteers swelled 50 google employees working 20 time ultimately tunney coworkers used bigquery discover vulnerable github software projects discovered 2,600 projects time directly indirectly vulnerable sent pull requests close security holes also raised public awareness severe cybersecurity threat posed continued use vulnerable versions libraries subsequent post google open source blog effort noting san francisco municipal transportation agency recently hacked ransomware due usage vulnerable version apache commons collections 2011 kalle lasn founder left-wing magazine adbusters put call activists occupy wall street response perceived political corruption american democracy wall street context 2008 financial crisis aftermath tunney one first individuals respond lasn call quickly creating occupywallst twitter handle occupywallst.org web site july 14 2011 became main online hub occupy movement february 2014 tunney took back exclusive control occupy wall street twitter account originally created removing posting access activists previously access stated founding organizer movement wrote locked twitter account partly order keep mouthpiece democratic party also said large number twitter users misogynist transphobic tunney described occupy wall street far-left movement former comrades described technocratic fascist written viewed activists within occupy wall street disagreed taking initiative ows movement sat meetings trying devise ways boss around unskilled unintelligent parasites tunney vocal supporter gamergate movement contributed unsuccessful crowdfunding campaign create gamergate movement website posted support gamergate movement occupy wall street twitter account tunney prolific blogger twitter user often writes political topics twitter personal blogs websites political writing sometimes controversial extreme degree daily dot vice various twitter users speculated might trolling performing online performance art might expressing sincerely held views daily dot cited tunney saying free speech rights respected techies progressives hopefully 'll live see day muckraking progressive reporters/bloggers sent prisons tunney characterised activities trolling multiple times since march 2014 response question put askfm regards asker suspicion tunney trying deliberately piss liberals tunney wrote answer included sentence favorite tactic trolling progressives simply use newspeak tunney also said trolling way get away saying certain things current regime tunney said entirely different person offline 2014 tunney petitioned us government people hold referendum asking support retire government employees full pensions transfer administrative authority technology industry appoint google chairman eric schmidt ceo america tunney works software engineer google petition expired failed meet people signature threshold doctors found tumor 2012 since removed
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Computer security
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hal sparc64 sparc64 microprocessor developed hal computer systems fabricated fujitsu implements sparc v9 instruction set architecture isa first microprocessor sparc64 hal first microprocessor first sparc64 brand operates 101 118 mhz sparc64 used exclusively fujitsu systems first systems fujitsu halstation model 330 model 350 workstations formally announced september 1995 introduced october 1995 two years late succeeded sparc64 ii previously known sparc64+ 1996 sparc64 superscalar microprocessor issues four instructions per cycle executes order multichip design consisting seven dies cpu die mmu die four cache dies clock die cpu die contains majority logic execution units level 0 l0 instruction cache execution units consist two integer units address units floating-point units fpus memory units fpu hardware consists fused multiply add fma unit divide unit fma instructions really fused single rounding sparc64 vi fma unit pipelined four-cycle latency one-cycle-throughput divide unit pipelined significantly longer latencies l0 instruction cache capacity 4 kb direct-mapped one-cycle latency cpu die connected cache mmu dies ten 64-bit buses four address buses carrying virtual addresses lead cache die two data buses write data register file two cache dies implement data cache four buses one cache die deliver data instructions cpu cpu die contained 2.7 million transistors dimensions 17.53 mm 16.92 mm area 297 mm 817 signal bumps 1,695 power bumps mmu die contains memory management unit cache controller external interfaces sparc64 separate interfaces memory input/output i/o bus used access memory 128 bits wide system interface hal i/o hio bus 64-bit asynchronous bus mmu die area 163 mm four dies implement level 1 l1 instruction data caches require two dies caches capacity 128 kb latency caches three cycles caches four-way set associative data cache protected error correcting code ecc parity uses 128-byte line size cache die implements 64 kb cache portion cache tags cache die contains 4.3 million transistors dimensions 14.0 mm 10.11 mm die area 142 mm 1,854 solder bumps 446 signals 1408 power sparc64 consisted 21.9 million transistors fabricated fujitsu cs-55 process 0.40 µm four-layer metal complementary metal–oxide–semiconductor cmos process seven dies packaged rectangular ceramic multi-chip module mcm connected underside mcm solder bumps mcm 565 pins 286 signal pins 218 power pins organized pin grid array pga mcm wide buses connect seven dies sparc64 ii sparc64+ development sparc64 second-generation sparc64 microprocessor operated 141 161 mhz used fujitsu halstation model 375 141 mhz model 385 161 mhz workstations introduced november 1996 december 1996 respectively sparc64 ii succeeded sparc64 iii 1998 sparc64 ii higher performance due higher clock frequencies enabled new process circuit tweaks higher instructions per cycle ipc count due following microarchitecture improvements fabricated fujitsu cs-60 process 0.35 µm five-layer metal cmos process new process reduced area dies cpu die measuring 202 mm mmu die 103 mm cache die 84 mm sparc64 gp series related microprocessors developed hal fujitsu used fujitsu gp7000f primepower servers first sparc64 gp development sparc64 ii third-generation sparc64 microprocessor known sparc64 iii introduced sparc64 gp operated clock frequencies 225 250 275 mhz first microprocessor hal support multiprocessing main competitors hp pa-8500 ibm power3 sun ultrasparc ii sparc64 gp taped july 1997 announced 11 april 1998 225 250 mhz versions introduced december 1998 275 mhz version introduced march 1999 single-die implementation sparc64 ii integrated modifications cpu die two four cache dies numerous modifications improvements made microarchitecture replacement mmu new system interface using ultra port architecture improved branch prediction extra pipeline stage improve clock frequencies second fpu could execute add subtract instructions fpu less functionality added instead duplicate first save die area second fpu half size first three-cycle latency instructions complex sparc64 ii memory management unit mmu replaced simpler one compatible solaris operating system previously sparc64 systems ran sparc64/os derivative solaris developed hal supported sparc64 l1 caches halved capacity 64 kb 128 kb reduce die area reason two four cache dies integrated sparc64 ii associated performance loss mitigated provision large external l2 cache capacity 1 16 mb l2 cache accessed dedicated 128-bit data bus operates half clock frequency microprocessor l2 cache inclusive super-set l1 caches l1 l2 cache data protected ecc tags parity sparc64 ii proprietary system interface replaced one compatible ultra port architecture enabled sparc64 iii use chipsets sun microelectronics system bus operates half third quarter fifth frequency microprocessor maximum 150 mhz contained 17.6 million transistors 6 million logic 11.6 million contained caches tlbs die area 210 mm fabricated fujitsu cs-70 process 0.24 µm five-layer metal cmos process packaged 957-pad flip-chip land grid array lga package dimensions 42.5 mm 42.5 mm 957 pads 552 signals 405 power ground internal voltage 2.5 v i/o voltage 3.3 v. peak power consumption 60 w 275 mhz ultra port architecture upa signals compatible 3.3 v low voltage transistor transistor logic lvttl levels exception differential clock signals compatible 3.3 v pseudo emitter coupled logic pecl levels second third sparc64 gps fourth generation sparc64 microprocessors second sparc64 gp development first operated 400 563 mhz first versions operating 400 450 mhz introduced 1 august 2000 larger l1 instruction data caches doubled capacity 128 kb better branch prediction result larger bht consisting 16,384 entries support visual instruction set vis l2 cache built double data rate ddr sram contained 30 million transistors fabricated fujitsu cs80 process 0.18 µm cmos process six levels copper interconnect used 1.8 v internal power supply 2.5 3.3 v power supply i/o packaged 1,206-contact ball grid array bga measuring 37.5 mm 37.5 mm 1,206 contacts 552 signals 405 power ground third sparc64 gp identical second terms microarchitecture operated 600 810 mhz first versions introduced 2001 700 788 810 mhz versions introduced 17 july 2002 fabricated fujitsu 0.15 µm cs85 process six levels copper interconnect used 1.5 v internal power supply 1.8 2.5 v power supply i/o
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Computer architecture
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ipad 2 ipad 2 tablet designed developed marketed apple inc compared first ipad second model ipad line gained faster dual core a5 processor lighter build structure first ipad feature vga front-facing 720p rear-facing cameras designed facetime video calling device available initially three storage sizes – 16 32 64gb – two varying connectivity options – wi-fi wi-fi cellular variation device available either black white front glass panel however upon release 3rd generation ipad march 2012 16gb variation two connectivity options two front color options remained available product became available march may 2011 device received mixed positive reception various blogs publications although praised hardware improvement new apple a5 chip software restriction ipad 2 ios general drew criticism various technology commentators device sold well first month sales 2.4–2.6 million units sold 11.12 million units sold third quarter 2011 popular product lower screen resolution performance two retina models followed lighter build longer battery life remained apple line-up entry-level ipad model three years march 2014 latterly silent upgrade die-shrunk version a5 processor basic design formed core first ipad mini screen pixel count similar features smaller size ipad 2 device receive six major versions ios 4 9 ios 12 released iphone 5s ipad air ipad mini 2 apple sent invitations journalists february 23 2011 media event march 2 march 2 2011 ceo steve jobs unveiled device yerba buena center arts despite medical leave upon announcement ipad 2 original ipad discontinued sales online apple authorized retail stores apple began selling ipad 2 website march 11 u.s. retail stores 5 pm local time date many stores major cities new york sold within hours online shipping delays increased three four weeks sunday four five weeks tuesday ipad 2 released internationally 25 countries march 25 2011 countries included australia austria belgium canada czech republic denmark finland france germany greece iceland italy ireland hungary luxembourg mexico netherlands new zealand norway poland portugal spain sweden switzerland united kingdom april 29 2011 release date japan postponed due earthquake tsunami struck nation march 11 2011 ipads delayed due nand flash storage chip used ipads created toshiba affected earthquake tsunami thus resulting suspension operations indefinite period time slowdown caused analysts downgrade apple stock ipad 2 later released hong kong south korea singapore philippines malaysia countries including japan april 29 2011 released numerous nations include china estonia thailand brazil russia taiwan two major release dates may 6 27 32 64gb models discontinued march 7 2012 upon introduction third generation ipad 16gb wi-fi 16gb wi-fi 3g models discontinued march 18 2014 late march 2011 ipad 2 released alongside ios 4.3 primarily introduced airplay mirroring home sharing among features october 12 2011 upon release iphone 4s ipad upgradable ios 5 firmware brought 200 new user features ios compatible devices including notification center imessage reminders updated notifications system using new banner style instead previously used pop-up alert style ipad 2 comes several applications default including safari mail photos video music itunes store maps notes calendar photo booth contacts app store also available default application enables users download database 800,000 applications price applications set developers like ios devices ipad 2 sync music videos apps photos mac pc using itunes although using ios 5 later user connect ipad computer icloud also allows users backup sync data compatible ios devices via internet game center available native social gaming platform ios games downloaded via app store feature enabled able integrate achievement points high-scores bonus system across ios devices single accumulative points social platform although tablet designed make phone calls cellular network user use wired headset built-in speaker microphone place phone calls wi-fi cellular using voip application ipad 2 also adds ability run garageband imovie iwork apps pages keynote numbers applications come ipad instead official applications apple sold within app store march 7 2012 unveiling third generation ipad firmware ipad 2 upgradable ios 5.1 scott rohde senior sony executive described ipad game console disguised device appropriated business workplace september 19 2012 almost week announcement iphone 5 ios 6 released numerous ios devices including ipad 2 however ios 6 features available ipad 2 software upgrade downloadable air ota update package contains two-hundred new features including mapping software designed apple dubbed apple maps clock app features timer stopwatch alarm facebook integration among new features tweaks ipad 2 compatible ios 7 released september 18 2013 however features available example like iphone 4 notification center control center use transparent style instead translucent style later ios models also airdrop first released ios 7 supported ipad 4 later ipad 2 run ios 8 released september 17 2014 making first ios device run five major versions ios including ios 4 5 6 7 8 os runs device new features work relatively aged hardware therefore performance limited users also reported numerous problems receiving update including accessibility features battery-related issues many users predicted ipad 2 going dropped updating ios 8 along iphone 4 process happened iphone 3gs ipod touch fourth generation earlier models considering model 3 years old confirmed june 8 2015 apple wwdc ipad 2 would run ios 9 made ipad 2 first ios device run six major versions ios previous releases though many headline features unavailable ipad 2 including predictive siri translucency effects split-view slide-over picture-in-picture multitasking health app ios 9 said feature performance improvements may help aging device function smoothly initial tests suggest significantly impact available space a5-based devices also run ios 9 including iphone 4s five major ios versions ipad mini four major ios versions ipod touch 5g four major ios versions june 13 2016 release ios 10 apple dropped continuing compatibility ipad 2 hardware limitations goes ipad 3rd generation ipad mini 1st generation making ios 9 final version run device ipad 2 one many computers mobile devices susceptible broadpwn exploit publicized july 2017 apple quickly released update ios 10 fix problem fix never released ios 9 earlier versions ios result older apple devices incompatible ios 10 including ipad 2 left vulnerable indefinitely raised concerns potentially widespread attacks using exploit particularly locations concentrated ipad 2 deployment certain primary secondary schools january 2018 apple suddenly started firmware signing ios 6.1.3 ipad 2 iphone 4s allowing users downgrade devices ios 6. ios 8 available over-the-air update ios 6 allowing users update devices ios 8.4.1 august 2019 still supported ipad 2 features apple a5 package-on-package pop system-on-chip soc comprises 1 ghz dual-core 32-bit cortex-a9 cpu 512 mb ram dual-core powervr sgx543mp2 gpu features include front rear cameras three-axis gyroscope headset controls proximity ambient light sensors microphone magnetometer accelerometer 9.7 inch multi-touch screen maximum resolution 1024×768 hence resulting 132 ppi ipad 2 four physical switches including home button near display returns user home screen three plastic physical switches sides wake/sleep volume up/down third switch either screen rotation lock mute home button ipad 2 easier double tap previous generation ipad apple reduced size ipad eliminating stamped sheet metal frame display integrating new thinner glass technology touch screen overlay slightly reducing space display battery ipad 2 screen thinner lighter yet stronger original ipad ipad 2 also supports screen mirroring via digital av adapter airplay ios 5 ipad 2 25 w·h rechargeable lithium-ion polymer battery lasts 10 hours like original ipad charged via usb included 10 w 2 power adapter battery 2.5 mm thick 59 smaller original three cells instead two improvements allowed injection-molded plastic support frame omitted 10 w usb power adapter provides 4x power conventional usb port tablet audio frequency response 20 hz 20 khz without third-party software play following audio formats he-aac aac protected aac mp3 mp3 vbr audible formats 2 3 4 aea aax aax+ alac aiff wav revised tablet adds front- rear-facing cameras allow facetime video calls ipad 2s third generation ipad iphone 4 4s fourth-generation ipod touch macintosh computers running mac os x 10.6.6 later webcam 0.3 mp front camera shoots vga-quality 30 frame/s video vga-quality still photos 0.7 mp back camera shoot 720p hd video 30 frame/s 5× times digital zoom shoot photo fullscreen aspect ratio rear camera shoots video 16:9 widescreen match 720p standard although central 4:3 part recording shown screen recording forward-facing camera shoots 4:3 apple a5 chip doubles processing speed graphics processing nine times faster previous ipad however benchtests hardware assessments performed various third party news sources technology blogs indicate claims exaggerated benchmark assessment conducted anandtech showed gpu ipad 2 3 times faster original ipad cpu benchmarks conducted ipad 2 iosnoops indicate 66 performance increase compared original ipad 3g versions ipad 2 offer cdma2000 support customers using device cdma network gsm/umts support customers using device gsm/umts network ipad wi-fi 3g model includes a-gps receiver tracking user location given permission also ipad 2 3g model includes plastic cap-like band top back 3g antenna metallic grille microphone replaced matching plastic black grille 3g model gsm models ipad 2 use sim card cdma models use esn connect cellular network device 15 lighter 33 thinner original ipad thinner iphone 4 0.5 mm wi-fi version gsm cdma versions known respectively verizon versions us differ weight slightly due mass difference gsm cdma cellular radios gsm model cdma model size ipad 2 also less original ipad 9.50×7.31×0.34 241.2×185.7×8.8 mm compared original ipad size 9.56×7.47×0.5 242.8×189.7×13.4 mm announcement release third generation ipad ipad 2 continued available purchase received hardware upgrade upgraded variant ipad 2 features smaller version apple a5 soc able reduce battery consumption benchmark tests conducted anandtech concluded upgraded variant able last longer least hour half depending task conducted device maximum temperature device heated also less original ipad 2 tests conducted organisation revealed upgraded variant able operate 1 degree lower performing intensive tasks performance difference two variants according anandtech negligible smart cover first introduced ipad 2 screen protector magnetically attaches face ipad cover three folds allow convert stand also held together magnets original ipad owners could purchase black case included similarly folding cover smart cover meant minimal easily detachable protects screen smart covers microfiber bottom cleans front ipad wakes ipad cover removed five different colors polyurethane leather leather expensive polyurethane version apple offers several accessories ipad 2 adapters proprietary 30-pin dock connector ipad port besides headphone jack dock holds ipad upright angle dock connector audio line port ipad use bluetooth keyboards also work macs pcs ipad charged standalone power adapter wall charger also used ipods iphones 10 w charger included ipad ipad 2 received mixed positive reviews praising apple a5 processor 720p camera joshua topolsky engadget said n't yet made leap feel free take deep breath dive – ipad 2 good gets right really quite good jason snell macworld said following though ipad 2 improvement original ipad numerous ways ’ still evolutionary product revolutionary one ’ happy current ipad ’ reason dump ’ shinier newer one say millions people ’ mean shiny ’ invested ipad accessories dock case keep mind probably ’ able use new ipad techcrunch mg siegler stated let sum simple way ipad 2 buy one maybe — depends factors want buy one yes use information wisely closed proprietary nature ios garnered criticism particularly digital rights advocates electronic frontier foundation computer engineer activist brewster kahle internet-law specialist jonathan zittrain free software foundation protested ipad introductory event targeted ipad defective design campaign competitor microsoft via pr spokesman also criticized apple control platform issue restrictions imposed design ios namely drm intended lock purchased media apple platform development model requiring yearly subscription distribute apps developed ios centralized approval process apps well apple general control lockdown platform particularly issue ability apple remotely disable delete apps tech community expressed concern locked-down ios represents growing trend apple approach computing particularly apple shift away machines hobbyists tinker note potential restrictions stifle software innovation ipad 2 users reported performance issues running ios 8 apple improved performance ipad 2 iphone 4s ios 8.1.1 update however 2 devices still n't run fast later models first weekend sale one million units sold soon first weekend ashok kumar technology analyst financial firm predicted apple would sell 35 million ipad 2s 2011 investment banking firm piper jaffray monitored initial sales ipad 2 reported 70 ipad 2 sales first-time ipad buyers 49 buyers owning pc compared initial buyers original ipad 26 buyers owned pc 12,000 units sold auction site ebay first two weeks release iphone 4s released rumors third generation ipad caused decline ipad 2 sales official figures released fourth quarter 2011 indicate apple sold 11.4 million ipads third quarter 166 increase third quarter 2010 product helped create newer larger markets apple south east asia 2011 two ipad 2 tablets taken international space station approved apple products taken iss include ipod also two iphone 4 phones personal computing system aboard iss various versions thinkpad laptop ibm later lenovo brand applications ipads used include angry birds game iss fit international space station food intake tracker tracking astronauts food consumption
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Operating systems
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windows nt startup process windows nt startup process process windows nt 4.0 windows 2000 windows xp windows server 2003 operating systems initialize windows vista later process changed significantly see windows vista startup process information changed windows nt installer works similarly regular windows nt install except runs cd-rom boot method work bios must compatible el torito specification iso 9660 file system install cd fully compatible standard although level 1 file names n't file version appended boot image emulation type 1 sector long 2048 bytes loaded segment 0x7c0 extracted iso image using file-extraction program 7-zip winzip iso image also hybridized like iso images linux distributions therefore contain master boot record mbr makes unable boot copying image block device pen drive installer also run ms-dos command prompt previous versions microsoft windows already installed upgraded run installer ms-dos based operating system windows 98 windows user must start system dos mode execute i386/winnt.exe cd-rom floppy disk containing ms-dos used start installer versions installer floppies also available sale windows vista onwards installer runs boot.wim contains bootable version windows pe windows pe 2.0 based windows vista kernel later windows pe versions based later windows versions regular cd-rom install bios executes post searches boot descriptor cd-rom boot descriptor points boot catalog file iso 9660 file system bios searches boot image compatible current architecture loads memory runs boot image analogous boot sector hard drive boot image loads setupldr.bin analogous ntldr fails reason message displayed saying ntldr found may misleading moreover ntldr cd never used loading phase installer process also assumes file versions unavailable starting boot loader boot image checks whether windows install system already present starts codice_1 install found disk mbr starts boot loader directly thus obviating need codice_1 codice_1 started displays string press key boot cd waits user input none detected seconds boots next device behavior essential booting second stage installer starts hard disk codice_4 codice_5 composed two binary files concatenated also found installation cd compressed cab files first file codice_6 flat binary file loads second file second file regular exe file portable executable format codice_4 second file codice_8 codice_5 second file codice_10 codice_8 codice_10 embedded file system drivers basic access fat ntfs iso 9660 differently regular *.sys drivers boot loader uses bios interrupts access boot disk also contain built-in ini parser cab decompressor installer starts running prints string setup inspecting computer hardware configuration ... codice_13 called system information stored memory displays blue screen vga text mode title windows setup white line bottom behaves status bar looks codice_14 parses file works key-value database like *.ini *.inf registry keys may either contain list files associated install location script line therefore database stores data code parsing blank lines ignored sections name merged file codice_15 also loaded resolve hardware quirks key-value syntax codice_16 section follows installer asks additional drivers need loaded loads text mode drivers loaded floppy disk hidden feature shows screen prompting user select computer type f5 pressed first message text mode drivers different pnp drivers loaded regardless hardware present loading phase installer displays messages screen current file loaded message setup loading files file description ... files loaded phase located sections ending codice_17 sections key gives driver name value gives file driver name looked section without codice_17 suffix find driver user-friendly name kernel also needs registry hive mounted load registry codice_19 also loaded file names files loaded boot loader hard-coded except drivers pnp devices identified bus driver address checked section codice_20 corresponding driver name given used step boot files loaded boot loader message setup starting windows displayed kernel starts like normal install starts drivers loads service codice_21 runs kernel mode starts gui still text mode drivers nt based bios interrupts used anymore user asked choose file system layout selected partition formatted necessary files txtsetup.sif copied system creates registry hives automatically restart system nt system start bootstrap section hiveinfs points files used fill hives default values fresh install section named codice_22 files reg files also ini files understood ini interpreter bundled installer disk formatter program statically linked codice_21 many freeware tools available internet customize txtsetup.sif creation unattended installs integrate drivers hotfixes process sometimes referred slipstreaming following command shows remastered cd created minimum set options linux assumes current directory cd mount point image created home directory file codice_24 used make install unattended required present model file cd named codice_25 setup tries detect winnt.sif codice_26 directory root directory floppy disk windows nt startup process starts computer finds windows boot loader portion windows operating system responsible finding microsoft windows starting prior windows vista however boot loader ntldr microsoft also released operating systems intel itanium processors use ia-64 architecture boot loader editions windows ia64ldr.efi later referred simply ia64ldr extensible firmware interface efi program boot loader executed searches windows operating system windows boot manager reading boot configuration data bcd complex firmware-independent database boot-time configuration data predecessor codice_5 reading simpler codice_28 boot.ini file missing boot loader attempt locate information standard installation directory windows nt 2000 machines attempt boot codice_29 windows xp 2003 machines boot codice_30 databases may contain list installed microsoft operating systems may loaded local hard disk drive remote computer local network ntldr supports operating systems installed disks whose file system ntfs fat file systems cdfs iso 9660 udfs windows boot manager also supports operating systems installed inside vhd file stored ntfs disk drive windows 2000 later versions windows hibernation supported windows boot loader starts search operating systems searching hiberfil.sys ntldr looks root folder default volume specified boot.ini windows boot manager looks location hiberfil.sys bcd file found active memory set found boot loader loads contents file compressed version physical memory dump machine memory restores computer state prior hibernation next boot loader looks list installed operating system entries one operating system installed boot loader shows boot menu allow user select operating system non nt-based operating system windows 98 selected specified ms-dos style path e.g c boot loader loads associated boot sector file listed boot.ini bcd default bootsect.dos file name specified passes execution control otherwise boot process continues operating system starts certain basic drivers flagged boot loaded memory appropriate file system driver partition type ntfs fat fat32 windows installation resides amongst point boot process boot loader clears screen displays textual progress bar often seen due initialization speed windows 2000 also displays text starting windows ... underneath user presses f8 phase advanced boot menu displayed containing various special boot modes including safe mode last known good configuration debugging enabled case server editions directory services restore mode boot mode selected f8 never pressed booting continues following files loaded sequentially next ntdetect.com windows nt kernel ntoskrnl.exe hardware abstraction layer hal.dll loaded memory multiple hardware configurations defined windows registry user prompted point choose one kernel memory boot-time device drivers loaded yet initialized required information along information detected hardware windows services stored codice_31 portion registry set registry keys collectively called control set multiple control sets typically two kept event settings contained currently-used one prohibit system booting codice_31 contains control sets labeled codice_33 codice_34 etc. well codice_35 regular operation windows uses codice_35 read write information codice_35 reference one control sets stored registry windows picks real control set used based values set codice_38 registry key control set chosen codice_44 key gets set accordingly codice_40 key also set codice_44 end boot process codice_42 also set codice_44 boot process completes successfully services started order group started provided following keys purposes booting driver may one following finished control passed boot loader kernel initialization kernel subsystem windows executive subsystems done two phases first phase basic internal memory structures created cpu interrupt controller initialized memory manager initialized creating areas file system cache paged non-paged pools memory object manager initial security token assignment first process system process manager system idle process well system process created point second phase involves initializing device drivers identified ntldr system drivers process loading device drivers progress bar visible bottom display windows 2000 systems windows xp windows server 2003 replaced animated bar represent actual progress prior windows xp part boot process took significantly longer drivers would initialized one time windows xp server 2003 drivers initialized asynchronously boot system drivers loaded kernel system thread starts session manager subsystem codice_51 files opened autochk started smss.exe autochk mounts drives checks one time see whether cleanly unmounted autochk determines one volumes dirty automatically run chkdsk provides user short window abort repair process pressing key within 10 seconds introduced windows nt 4.0 service pack 4 earlier versions would allow user abort chkdsk since windows 2000 xp 2003 show text screen point unlike nt 3.1 4.0 displayed blue text screen user see different background picture holding mini-text-screen center screen show progress chkdsk boot time session manager subsystem session manager stores configuration codice_58 exact operation items based configuration set registry winlogon starts local security authority subsystem service lsass service control manager scm turn start windows services set auto-start also responsible responding secure attention sequence sas loading user profile logon optionally locking computer screensaver running login process follows user trying log local host codice_70 key used database user trying log another host netlogon service used carry data windows xp gina shown user presses secure attention sequence winlogon support plugins get loaded notified specific events lsass also supports plugins security packages rootkits bundle winlogon plugins loaded user logs keys allow multiple comma-separated values supplied allow malicious program executed time legit system file hashing algorithms stored sam database known broken winlogon responsibilities login process changed significantly windows vista userinit first program runs user credentials responsible start programs compose user shell environment shell program typically codice_71 started registry entry codice_72 pointed registry entry key codice_73 default value codice_74 evaluates codice_75 userinit runs startup programs following locations successfully boot client must support pxe booting windows deployment services wds component must installed server installed default wds successor remote installation services ris pxe program found bios rom chip network card pxe booting technology specific windows also used start linux system fact linux system act server service dhcp tftp pxe used start windows setup install system client computer run operating system ram latter called remote boot introduced windows xp embedded sp1 available flavor windows general process methods follows boot information negotiation layer binl windows 2000 service running server communicates client nbp already loaded pxe
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Operating systems
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macintosh quadra 660av macintosh quadra 660av originally called macintosh centris 660av personal computer designed manufactured sold apple computer inc. july 1993 september 1994 introduced alongside quadra 840av av model numbers signifies video input output capabilities enhanced audio 660av discontinued months introduction power macintosh 6100/60av apple also sold power macintosh upgrade card upgraded 660av match 6100/60av specifications users ready move powerpc quadra 630 also suitable replacement 660av uses pizza box form factor earlier centris 610 660av full motorola 68040 instead 610 fpu-less 68lc040 like 840av 660av features video input/output capability onboard 3210 digital signal processor clocked 55 mhz make video handling less burden cpu 660av also first macintosh include geoport optional geoport telecom adapter enables fax modem capabilities earliest centris 660avs older auto-inject floppy drive opening similar 610 centris models quadra models drive similar power macintosh 6100 lacking ‘ auto-inject ’ feature models deep round indent center floppy drive slot make possible insert disk way quadra av macs introduced new universal rom codenamed supermario would later used powerpc systems includes scsi manager 4.3 sound manager 3.0 also vectorized making easier patch introduced july 29 1993 introduced october 1 1993
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Computer architecture
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mcclim mcclim free software implementation common lisp interface manager project named mike mcdonald person started
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Programming language topics
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white ops white ops ad verification bot detection cybersecurity firm white ops cofounded chief scientist dan kaminsky 2012 white ops president michael tiffany ash kalb tamer hassan ceo company gene fay company ’ coo headquartered new york city international offices 2016 discovered methbot network bots six thousand online publishers platforms affected including facebook generating 3- 5 million fraudulent ad revenue per day 2017 white ops uncovered 3ve bot network one largest ad fraud enterprises yet discovered 1.7 infected computers leading thirteen department justice indictments 2018 investigation network google fbi originally operating prevent ad fraud online 2018 white ops expanded ad fraud activities include television detects bots bot networks uses human verification part process processes trillion transactions per month 2018 white ops produced reports ad fraud association national advertisers since 2014 2017 white ops began partnering trade desk block fraudulent impressions advertisers make bids following year 2018 whiteops began similar partnership beachfront media video management platform telaria white ops also partners adobe advertising cloud provide independent third-party bot detection 2019 white ops began partnering media.net
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Computer security
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adaptive replacement cache adaptive replacement cache arc page replacement algorithm better performance lru least recently used accomplished keeping track frequently used recently used pages plus recent eviction history algorithm developed ibm almaden research center 2006 ibm granted patent adaptive replacement cache policy basic lru maintains ordered list cache directory resource entries cache sort order based time recent access new entries added top list bottom entry evicted cache hits move top pushing entries arc improves basic lru strategy splitting cache directory two lists t1 t2 recently frequently referenced entries turn extended ghost list b1 b2 attached bottom two lists ghost lists act scorecards keeping track history recently evicted cache entries algorithm uses ghost hits adapt recent change resource usage note ghost lists contain metadata keys entries resource data i.e entry evicted ghost list data discarded combined cache directory organised four lru lists t1 b1 together referred l1 combined history recent single references similarly l2 combination t2 b2 whole cache directory visualised single line inner brackets indicate actual cache although fixed size move freely across b1 b2 history l1 displayed right left starting top indicated marker indicates target size t1 may equal smaller larger actual size indicated entries re- entering cache t1 t2 cause move towards target marker free space exists cache marker also determines whether either t1 t2 evict entry arc currently deployed ibm ds6000/ds8000 storage controllers sun microsystems scalable file system zfs uses variant arc alternative traditional solaris filesystem page cache virtual memory modified allow locked pages currently use vacated postgresql used arc buffer manager brief time version 8.0.0 quickly replaced another algorithm citing concerns ibm patent arc vmware vsan formerly virtual san hyper-converged software-defined storage sds product developed vmware uses variant arc caching algorithm
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Operating systems
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distributed universal number discovery distributed universal number discovery dundi voip routing protocol provides directory services asterisk systems dundi peered nodes share dialplan information protocol actually carry calls rather provides addressing information peers dundi cluster query peers telephone number call requested user result query dial string asterisk application dial protocol invented mark spencer author asterisk asterisk pbx systems use dundi peered cooperating system dundi nodes certain configuration access dundi instance least one node dundi configuration one limit number consecutive lookups peers setting ttl dundi peer advertise extensions context e.g connect local e.164 number advertise dundi configuration assigns priority weight advertised extension low values represent high priority must chosen first one answer received lookup asterisk cli one lookup hand test dundi configuration works dundi lookup tells pbx ask known peers know reach extension 301 priv network answer consists 6 parts order prevent network overloading time keep responses quick possible involved peers cache lookups see used keys may become invalid period lookup expiry date defaults one hour context given lookup dundi defaults e.164 context means looking normal international phone-numbers like 0031201234567 bogus number amsterdam netherlands order peer least one peer e164 trust group peers group bound digium gpa digium general peering agreement pdf
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Internet protocols
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layered security layered security also known layered defense describes practice combining multiple mitigating security controls protect resources data like security methods layered security designed protect assets asset anything want protect include people property data etc layered security used environment military operations individuals community residents homeowners neighborhood watch groups etc words layered security practice using many different security controls different levels protect assets provides strength depth reduce effects threat goal create redundancies backups case security measures fail bypassed defeated placing assets innermost perimeter provide layers security measures increasing distances protected asset number layers security measures use depend threat importance asset term bears similarity defense depth term adopted military strategy involves multiple layers defense resist rapid penetration attacker yield rather exhaust too-rigid tactics incursion progresses resources consumed progress slowed halted turned back information assurance use term defense depth assumes merely technical security tools deployment also implies policy operations planning user training physical access security measures direct information assurance personnel involvement dealing attempts gain unauthorized access information resources within defense depth security strategy layered security regarded merely delaying tactic used buy time bring security resources bear deal malicious security cracker activities layered security example swiss cheese model cumulative act effect used risk analysis risk management model security systems likened multiple slices swiss cheese stacked side side risk threat becoming reality mitigated fact must pass holes defenses i.e trapped detected different defense defenses different kinds locations layered behind therefore theory lapses weaknesses one defense easily allow risk materialize since defenses also exist prevent single point weakness every category threat effective control deployed mitigate threat security vendors sometimes cite differing solutions grouped consumer enterprise categories ad hoc security strategy numerous vendors abundance different sometimes incompatible security solutions products leave gaps protection whereas vertically integrated vendor stack could provide comprehensive defense single-vendor solutions improve interoperability components complete security strategy may offer performance price benefits multi-vendor approach contrasting commercial security product argument best breed approach provides effective protection single vendor vertically integrated product stack may offering choice vendors want monopolize client customer business could also argued component comprehensive security strategy evaluated performance within niche open compatibility non-integrated components whole
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Computer security
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collateral circulation collateral circulation alternate circulation around blocked artery vein via another path nearby minor vessels may occur via preexisting vascular redundancy analogous engineered redundancy circle willis brain may occur via new branches formed adjacent blood vessels neovascularization eye retinal embolism formation may provoked pathological conditions high vascular resistance ischaemia example usefulness collateral circulation systemic thromboembolism cats thrombotic embolus lodges external iliac artery common iliac artery blocking external internal iliac arteries effectively shutting blood supply hind leg even though main vessels leg blocked enough blood get tissues leg via collateral circulation keep alive blood flow brain humans animals maintained via network collateral arteries anastomose join circle willis lies base brain circle willis so-called communicating arteries exist front anterior back posterior parts circle willis well left right side circle willis another example humans animals acute myocardial infarction heart attack collateral circulation heart tissue sometimes bypass blockage main artery supply enough oxygenated blood enable cardiac tissue survive recover central retinal vein occlusion neovascularization may restore blood flow retina new vessels bulk also presents risk causing acute glaucoma blocking drainage aqueous humour hepatic cirrhosis arising congestion hepatic portal vein may give rise collateral circulation branches portal caval veins liver two caval veins consequences newly established venous collaterals arising portal hypertension include esophageal varices hemorrhoids portocaval collateral circulation
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Computer security
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document structuring document structuring subtask natural language generation involves deciding order grouping example paragraphs sentences generated text closely related content determination nlg task assume four sentences want include generated text 24 4 orderings messages including orderings better others example texts shown human readers prefer 1234 2314 4321 ordering also many ways sentences grouped paragraphs higher-level structures sections example 8 2**3 ways sentences 1234 grouped paragraphs including ordering human readers prefer groupings others example 12 34 preferred 1 23 4 document structuring task choose ordering grouping sentences results coherent well-organised text reader perspective three basic approaches document structuring schemas corpus-based heuristic schemas templates explicitly specify sentence ordering grouping document well content determination information typically constructed manually analysing corpus human-written texts target genre extracting document template texts schemas work well practice texts short 5 sentences less and/or standardised structure problems generating texts longer fixed structure corpus-based structuring techniques use statistical corpus analysis techniques automatically build ordering and/or grouping models techniques common automatic summarisation computer program automatically generates summary textual document principle could applied text generated non-linguistic data work infancy part challenge texts generated natural language generation systems generally expected fairly high quality always case texts generated automatic summarisation systems final approach heuristic-based structuring algorithms perform structuring task based heuristic rules come theories rhetoric psycholinguistic models and/or combination intuition feedback pilot experiments potential users heuristic-based structuring appealing intellectually difficult get work well practice part heuristics often depend semantic information sentences relate always available hand heuristic rules focus best text readers whereas approaches focus imitating authors many human-authored texts well structured perhaps ultimate document structuring challenge generate good narrative—in words text starts setting scene giving introduction/overview describes set events clear fashion readers easily see individual events related link together concludes summary/ending note narrative sense applies factual texts well stories current nlg systems good job generating narratives major source user criticism generating good narratives challenge aspects nlg fundamental challenge probably document structuring
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Computational linguistics
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shazam software shazam comprehensive econometrics statistics package estimating testing simulating forecasting many types econometrics statistical models shazam originally created 1977 kenneth white shazam version 11 available windows platforms server workstation desktop windows xp later shazam editions read write fixed free format text formats using read format statements data stored observation row variable column without variable names supplied windows environment formats comma-separated values csv microsoft excel xls xlsx may also read written shazam professional edition contains comprehensive data import capabilities data connector sql editor allowing import machine data source tab space comma separated text formats file-based proprietary binary formats including various microsoft excel formats well microsoft access lan wan internet data source user driver system addition shazam import data database management systems dbms shazam ships drivers common data database management systems shazam extensible development shazam procedures included reused shazam command files numerous shazam procedures written available shazam website many sites throughout internet shazam currently available four editions shazam command line edition shazamd shazamq text user interface versions allow batch processing operate double quad precisions shazam standard edition shazamw adds native windows application incorporates multiple document interface mdi interface including command data matrix graph editors workspace viewer along integrated online help samples examples shazam professional edition shazamp adds menu wizard driven facilities executing shazam techniques data connector sql editor well integrated debugger main guide available using shazam offers detailed descriptions shazam features commands options well providing guidance statistical techniques performed algorithms used construction shazam techniques contains numerous theoretical explanations practical examples sample code
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Programming language topics
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result set sql result set set rows database well metadata query column names types sizes column depending database system number rows result set may may known usually number known front result set built on-the-fly result set effectively table codice_1 clause used query impose certain sort condition rows without clause guarantee whatsoever order rows returned
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Databases
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e4m encryption masses e4m free disk encryption software windows nt windows 9x families operating systems e4m longer maintained author paul le roux joined shaun hollingworth author scramdisk produce commercial encryption product drivecrypt security company securstar popular source-available freeware program truecrypt based e4m source code however truecrypt uses different container format e4m makes impossible use one programs access encrypted volume created shortly truecrypt version 1.0 released february 2004 truecrypt team reported receiving emails wilfried hafner manager securstar claiming paul le roux stolen source code e4m securstar employee according truecrypt team emails stated le roux illegally distributed e4m authored illegal license permitting anyone base derivative work e4m distribute freely hefner alleges le roux right claiming versions e4m always belonged securstar time led truecrypt team stop developing distributing truecrypt
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Computer file systems
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comparison open-source operating systems tables compare free software open-source operating systems versions support feature first version supports listed
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Operating systems
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stacheldraht stacheldraht german barbed wire malware written mixter linux solaris systems acts distributed denial-of-service ddos agent tool detects automatically enables source address forgery stacheldraht uses number different denial-of-service dos attacks including user datagram protocol udp flood internet control message protocol icmp flood transmission control protocol tcp syn flood smurf attack combines features trinoo tribe flood network tfn adds encryption
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Computer security
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