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opera file system opera file system file system used 3do discs recently implemented linux operafs read copied clonecd v4.2 later
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Computer file systems
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sql programming tool field software sql programming tools provide platforms database administrators dbas application developers perform daily tasks efficiently accurately database administrators application developers often face constantly changing environments rarely completely control many changes result new development projects modifications existing code deployed production always produce expected result organizations better manage development projects teams develop code suppliers sql programming tools normally provide facility database administrator application developer aid database management quality code-deployment practices sql programming tools may include following features sql editors allow users edit execute sql statements may support following features tools may display information database objects relevant developers database administrators users may tools also provide features display dependencies among objects allow users expand dependent objects recursively example packages may reference views views generally reference tables super/subtypes database administrators application developers use session browsing tools view current activities user database check resource-usage individual users statistics information locked objects current running sql individual session dbas create edit delete disable enable user-accounts database using security-management tools dbas also assign roles system privileges object privileges storage-quotas users tools offer features debugging stored procedures step step step run exception breakpoints view set variables view call stack users debug program-unit without making modification including triggers object types monitoring tools may show database resources — usage summary service time summary recent activities top sessions session history top sql — easy-to-read graphs database administrators easily monitor health various components monitoring instance application developers may also make use tools diagnose correct application-performance problems well improve sql server performance test data generation tools populate database realistic test data server client side testing purposes also kind software upload sample blob files database
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Databases
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openpic mpic order compete intel advanced programmable interrupt controller apic enabled first intel 486-based multiprocessor systems early 1995 amd cyrix proposed somewhat similar-in-purpose openpic architecture supporting 32 processors openpic architecture least declarative support ibm compaq around 1995 x86 motherboard released openpic however openpic failure x86 market amd licensed intel apic architecture amd athlon later processors ibm however developed multiprocessor interrupt controller mpic based openpic register specification reference ibm design processors share mpic dcr bus access bus controlled dcr arbiter mpic supports four processors 128 interrupt sources various implementations mpic included powerpc reference designs retail computers ibm used mpic based openpic 1.0 rs/6000 f50 one based openpic 1.2 rs/6000 s70 systems also used dual 8259 pci-isa bridges ibm mpic also used rs/6000 7046 model b50 apple hydra mac i/o mio chip 1990s classic mac os era implemented mpic alongside scsi controller adb controller geoport controller timers apple implementation open pic apple documentation era spells first mio chip common hardware reference platform based version 1.2 register specification supported two processors 20 interrupt sources mpic also incorporated newer k2 i/o controller used power mac g5s freescale also uses mpic compatible open pic powerquicc qoriq processors linux kernel-based virtual machine kvm supports virtualized mpic 256 interrupts based freescale variants
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Computer architecture
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ikari warriors ikari warriors vertically scrolling run gun shoot 'em arcade game developed snk published north america europe tradewest released 1986 originally titled japan ikari warriors snk first major breakthrough us release game released time many commando clones market distinguished ikari warriors rotary joysticks two-player mode player characters ikari warriors colonel ralf second lieutenant clark later king fighters series known outside japan paul vince ikari series battling hordes enemies according designer keiko iju game inspired popular rambo films takes name japanese title rambo ikari dasshutsu furious escape ralf clark also make appearance playable characters metal slug 6 metal slug 7 well king fighters series stan szczepanski holds official guinness world record 1,799,000 points player takes role commando-like warriors named ralf red clark blue must try reach village ikari enemy units attempting kill player include tanks enemy soldiers helicopters number power-ups along way help player achieve victory players must proceed bottom screen upwards towards village ikari trying prevent reaching village enemy soldiers units along way players may commandeer enemy tanks helicopters nes version help fight way enemy personnel tanks immune enemy bullets limited supply fuel sustain damage runs tank caught explosion taking player unless exit tank get clear blows helicopters two different weapons spread gun cannon may fly water rotating joystick changes direction character faced independent direction character moving controlled pushing joystick gives player freedom attack walk eight different directions shot fired directly front player warrior uses machine gun right hand throws grenades left player character takes long moving screen computer starts using call fire red spot appears tracking fire speed game ikari warriors first popular video game used rotary joysticks rotated addition pushed eight directions less successful tnk iii released 1985 also snk first used joysticks system also features two buttons one standard gun another lobbing grenades one games time allow two-player cooperative side-by-side gameplay use vehicles game cabinet standard upright model ikari warriors printed circuit boards pcbs manufactured two different versions snk pinout jamma pinout snk-pinout units put ikari warriors cabinets jamma-pinout units supplied conversion kits snk-pinout boards 22/44-pin edge connectors jamma-pinout pcbs 28/56-pin edge connectors types consist stack three boards interconnects ikari warriors uses snk model ls-30 joysticks contain 12-way rotary switch box joysticks connected pcb via auxiliary wiring harnesses game known simply ikari japan ikari warriors united states europe addition changing names main characters ralf clark paul vince military commander player rescues end game named general kawasaki japanese version named snk founder eikichi kawasaki colonel cook us/euro version named tradewest founder leland cook general kawasaki name unchanged nes version enemies game actually neo-nazis evidenced presence swastika middle final room ikari warriors ported nintendo entertainment system ibm pc apple ii atari st atari 2600 atari 7800 amiga commodore 64 zx spectrum amstrad cpc msx port conversions 16-bit machines released 1987 pc commodore 64 ports developed quicksilver software 1989 second c64 version released uk elite software nes version developed micronics atari 2600 atari 7800 ports released 1990 one final published games systems game also included snk 40th anniversary collection nintendo switch playstation 4 1996 next generation listed arcade version ikari warriors number 61 top 100 games time lauding innovative joysticks play balance power-ups offer invigorating boost player character capabilities without taking away game challenge computer video games enthusiastically reviewed classy amstrad personal computer conversion calling graphics simply brilliant gameplay awesomely addictive said players wo n't see better ... probably quite amstrad graphics close dammit arcade machine playability goes c+vg scale pc version game received 4 5 stars dragon ikari warriors spawned sequels victory road 1986 1989 snk released ikari warriors clone 1987 called guerrilla war known guevara japan game features communist fighters che guevara fidel castro heroes
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Computer architecture
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free space bitmap free-space bitmaps one method used track allocated sectors file systems simplistic design highly inefficient advanced hybrid implementations free space bitmaps used modern file systems simplest form free space bitmap bit array i.e block bits example zero would indicate free sector one indicates sector use sector would fixed size explanatory purposes use 4 gib hard drive 4096 byte sectors assume bitmap stored elsewhere example disk would require 1,048,576 bits one sector 128 kib increasing size drive proportionately increase size bitmap multiplying sector size produce proportionate reduction operating system os needs write file scan bitmap finds enough free locations fit file 12 kib file stored example drive three zero bits would found changed ones data would written across three sectors represented bits file subsequently truncated 8 kib final sector bit would set back zero indicating available use drive size grows amount time needed scan free space become unreasonable address real world implementations free space bitmaps find ways centralize information free space one approach split bitmap many chunks separate array stores number free sectors chunk chunks insufficient space easily skipped total amount free space easier compute finding free space entails searching summary array first searching associated bitmap chunk exact sectors available approach drastically reduces cost finding free space n't help process freeing space combined size summary array bitmap greater readily stored memory large number files scattered sectors freed enormous amount disk access necessary find sectors decrement summary counter flip bits back zero greatly reduces benefits bitmap longer performing function summarizing free space rapidly without reading disk
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Computer file systems
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super cars super cars top-view racing game gremlin interactive later produced lotus series games stylistically game influenced super sprint 9 tracks 4 difficulty levels raced order although last track race made harder usual races win money spent temporary handling power upgrades plus armour plating front/rear shooting missiles knock racers player must finish top 3 race progress initially 4 computer opponents added progress game car upgraded throughout game via shop section player given initial price also number options things say salesman right combination price drop followed super cars ii 1991 three cars available purchase game taraco neoroder turbo vaug interceptor turbo retron parsec turbo appears based real car time retron parsec turbo based cizeta-moroder v16t vaug interceptor based honda nsx taraco neoroder based alfa romeo sz sprint zagato slight changes slight contrast box art blue starter car taraco instead closely resembles contemporary european ford fiesta escort cosworth convertible retron also portrayed differently box art lamborghini countach instead cizeta
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Computer architecture
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hillar aarelaid hillar aarelaid born december 31 1967 founder first ceo estonia computer emergency response team cert-ee director general estonian data protection inspectorate 1999 2003 aarelaid one central officials charge responding computer attacks estonia bronze soldier tallinn controversy american expert bill woodcock observers praised aarelaid calm professionalism displayed attacks
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Computer security
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webmacro webmacro framework developing java servlets enforces model-view-controller framework project allowing clean separation concerns design particular webmacro keeps program source code absolutely separate presentation html code webmacro open source software webmacro initially created designed justin wells semiotek inc. mid-2000 project taken team sourceforge extensive discussions webmacro java servlet-interest mailing list time may influential sun microsystems decision move java server pages product model-view-controller architecture webmacro also used generate arbitrary text output templates one uses automated code generation template language similar language used apache velocity automated script perform migration apache velocity project started clean room re-implementation jon scott stevens geir magnusson jason van zyl agreement could reached adoption apache license current version webmacro bsd licensed
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Web technology
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william a. martin william arthur martin 1938-1981 computer scientist oklahoma city oklahoma graduating northwest classen high school state wrestling champion attended mit received bachelor degree 1960 master 1962 ph.d. 1967 electrical engineering supervision marvin minsky dissertation symbolic mathematical laboratory obtaining degrees worked teaching assistant mit beginning 1960 became assistant professor 1968 promoted associate professor electrical engineering 1972 1975 received academic tenure held joint appointment mit sloan school management research pulled towards project mac became laboratory computer science artificial intelligence laboratory researched expert systems finishing ph.d. dissertation symbolic mathematics martin co-founded macsyma project 1968 directed 1971 macsyma later became successful commercial product also core free maxima system martin worked automatic programming knowledge representation natural language processing
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Programming language topics
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data-centric security data-centric security approach security emphasizes security data rather security networks servers applications data-centric security evolving rapidly enterprises increasingly rely digital information run business big data projects become mainstream data-centric security also allows organizations overcome disconnect security technology objectives business strategy relating security services directly data implicitly protect relationship often obscured presentation security end common processes data-centric security model include technical point view information data -centric security relies implementation following data access control selective restriction access data accessing may mean viewing editing using defining proper access controls requires map information resides important important sensitive data designing appropriate controls encryption proven data-centric technique address risk data theft smartphones laptops desktops even servers including cloud one limitation encryption always effective network intrusion occurred cybercriminals operate stolen valid user credentials data masking process hiding specific data within database table cell ensure data security maintained sensitive information exposed unauthorized personnel may include masking data users developers third-party outsourcing vendors etc data masking achieved multiple ways duplicating data eliminate subset data needs hidden obscuring data dynamically users perform requests monitoring activity data layer key component data-centric security strategy provides visibility types actions users tools requested authorized specific data elements continuous monitoring data layer combined precise access control contribute significantly real-time detection data breaches limits damages inflicted breach even stop intrusion proper controls place 2016 survey shows organizations still n't assess database activity continuously lack capability identify database breaches timely fashion cloud computing evolving paradigm tremendous momentum unique aspects exacerbate security privacy challenges heterogeneity diversity cloud services environments demand fine-grained access control policies services flexible enough capture dynamic context attribute-based access requirements data protection recent decades many organizations rely managing database services public clouds amazon web services oracle cloud google cloud platform microsoft azure organize data approach limitations users managing security sensitive data instance hardware security appliances agents running database servers longer option requires innovative ways secure data databases using reverse proxy sitting clients applications database servers requirements supporting load balancing high availability fail-over data-centric security brings additional challenges database security vendors must meet
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Computer security
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parametricity programming language theory parametricity abstract uniformity property enjoyed parametrically polymorphic functions captures intuition instances polymorphic function act way consider example based set x type x x → x functions x higher-order function twice x → x given twice f f ∘ f intuitively independent set x family functions twice parametrized sets x called parametrically polymorphic function simply write twice entire family functions write type formula_1 x x → x individual functions twice called components instances polymorphic function notice component functions twice act way given rule families functions obtained picking one arbitrary function x → x would uniformity called ad hoc polymorphic functions parametricity abstract property enjoyed uniformly acting families twice distinguishes ad hoc families adequate formalization parametricity possible prove parametrically polymorphic functions type formula_1 x x → x one-to-one natural numbers function corresponding natural number n given rule f formula_3 f i.e. polymorphic church numeral n contrast collection ad hoc families would large set parametricity theorem originally stated john c. reynolds called abstraction theorem paper theorems free philip wadler described application parametricity derive theorems parametrically polymorphic functions based types parametricity basis many program transformations implemented compilers haskell programming language transformations traditionally thought correct haskell haskell non-strict semantics despite lazy programming language haskell support certain primitive operations—such operator codice_1—that enable so-called selective strictness allowing programmer force evaluation certain expressions paper free theorems presence seq patricia johann janis voigtlaender showed presence operations general parametricity theorem hold haskell programs thus transformations unsound general
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Programming language topics
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trust service provider trust service provider tsp person legal entity providing preserving digital certificates create validate electronic signatures authenticate signatories well websites general trust service providers qualified certificate authorities required european union switzerland context regulated electronic signing procedures term trust service provider coined european parliament european council important relevant authority providing non-repudiation regulated electronic signing procedure first brought electronic signatures directive 1999/93/ec initially named certification-service provider directive repealed eidas regulation became official july 1 2016. ref name= 1999/93/ec /ref regulation binding legislative act requires eu member states follow trust service provider responsibility assure integrity electronic identification signatories services strong mechanisms authentication electronic signatures digital certificates eidas defines standards trust service providers perform services authentication non-repudiation regulation provides guidance eu member states trust service providers shall regulated recognized trust service defined electronic service entails one three possible actions first may concern creation verification validation electronic signatures well time stamps seals electronically registered delivery services certifications required services second action entails creation verification well validation certificates used authenticate websites third action preservation electronic signatures seals related certificates elevated level qualified trust service service must meet requirements set eidas regulation trust services provide trust framework facilitates continued relations electronic transactions conducted participating eu member states organizations qualified trust service provider plays important role process qualified electronic signing trust service providers must given qualified status permission supervisory government body provide qualified digital certificates used create qualified electronic signatures eidas requires eu maintain eu trust list lists providers services received qualified status trust service provider entitled provide qualified trust services eu trust list trust service providers eu trust list required follow strict guidelines established eidas need provide stamps valid time date creating certificates signatures expired certificates need revoked immediately eu obliges trust service providers deliver appropriate training personnel employed trust service provider shall provide tools software hardware trustworthy capable preventing forgeries certificates produced one major intents eidas facilitate public business services especially conducted parties across eu member state borders transactions safely expedited means electronic signing services provided trust service providers regards ensuring integrity signatures eu member states required eidas establish “ points single contact ” pscs trust services ensure electronic id schemes used cross-board public sector transactions including exchange access healthcare information across borders advanced electronic signature legally binding eidas qualified electronic signature created qualified trust service provider carries higher probative value used evidence court signature ’ authorship considered non-repudiable authenticity signature easily challenged eu member states obligated accept qualified electronic signatures created qualified certificate member states valid according eidas regulation i.e article 24 2 signature created qualified certificate legal value handwritten signature court standards evolving additional standards including policy definitions trust service providers development european telecommunication standards institute etsi swiss digital signing standard zertes defined comparable concept certificate service providers certificate service providers need audited conformity assessment bodies appointed schweizerische akkreditierungsstelle united states nist digital signature standard dss current release know anything comparable qualified trust service provider would allow enhance non-repudiation signatory qualified certificate however authors forthcoming review commentators publicly discussing amendment similar eidas zertes approach trusted service provision allow stringent non-repudiable global transactions legal relevance international harmonization would required several research institutes associations expressed concern respect establishment small group centralized trust service providers per country authenticate digital transactions state construct may negative impact privacy given central role trust service providers many transactions council european professional informatics societies cepis fears trust service providers would gain collect information distinguishing attributes citizens subject authentication regard requirement preserve data resulting expected efforts keep evidence potential liability requests inaccurate id cepis sees risk trust service providers could create store log entries authentication processes information gained allows monitoring profiling involved citizens transaction counterpart also identifies user interests communication behaviour additionally sharpen profiles gained big data analysis would allow far-reaching insights citizens privacy relationships direct connection qualifying governmental bodies could allow gain access gained data profiles authors claim truly take advantage secure seamless cross-border electronic transactions assurance levels definitions technical deployment need specified precisely
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Computer security
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global file system computer science global file system historically referred distributed virtual name space built set local file systems provide transparent access multiple potentially distributed systems global file systems properties blocking interface buffering etc guaranteed path name corresponds object computers deploying filesystem also called distributed file systems file systems rely redirection distributed systems therefore latency scalability affect file access depending target systems reside andrew file system attempted solve campus environment using caching weak consistency model achieve local access remote files recently global file systems emerged combine cloud object storage versioning local caching create single unified globally accessible file system rely redirection storage device serves files local cache maintaining single file system meta data object storage described google patents advantages global file systems include ability scale object storage use snapshots stored object storage versioning replace backup create centrally managed consolidated storage repository object storage
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Computer file systems
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moonsound moonsound name sound card released msx home-computer system tilburg computer fair 1995 name moonsound originated software moonblaster written people use hardware plug-in synthesizer moonsound sound-card produced msx home-computer system based yamaha ymf278 opl4 sound chip capable 18 channels fm sound well 24 channels 12 16 bit sample-based synthesis arrived us branch microsoft abandoned msx system focusing ibm pc 2 mb instrument rom containing multisampled instruments unusual time factory came equipped one 128 kb sram chip user samples designed electronic engineer henrik gilvad produced sunrise swiss semi-hobby basis two generations made first small size pcb without box later larger size pcb fit msx cartridge available later version room two sample sram chips resulting 1 mb compressed user samples moonblaster software designed remco schrijvers based time-step sequencer software msx sound cards moonblaster came two versions one fm one sample-based synthesis later marcel delorme took software development sound effects like chorus delay reverb omitted due cost size usability reasons yamaha effect chip requires specialised memory effect routing basic 18 fm channels 24 channels sample-based sound shares effect setting creative step-time sequencer programmers made pseudo effects like chorus reverb delay overdubbing using dedicated channels repeat notes delay stereo panning effective quickly reduces musical complexity possible moonsound version 1.0 1 socket user sample ram moonsound version 1.1 1.2 2 sockets 1mb sram hackers found stack 2 additional sram chips resulting 2mb sram based opl4 chip moonsound compatible fm register opl1 opl2 opl3 msx-audio contains chip also compatible opl1 therefore older software make use moonsound 2 mb rom contained 330 mono samples mostly 22.050 khz 12 bits drums 44.1 khz fm part opl4 chip configured several ways four-operator fm allows complex sounds reduces polyphony eight waveforms available fm synthesis moonsound audio power supply isolated digital supply attempt reduce noise separate stereo audio output mixed internal msx sound additional software tools able rip sound loops digitally audio cds inserted cd-rom drive connected scsi ata-ide interfaces software designed henrik gilvad msx club gouda sunrise swiss today moonsound emulated msx emulators bluemsx openmsx
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Computer architecture
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john ousterhout john kenneth ousterhout born october 15 1954 professor computer science stanford university founded electric cloud john graham-cumming ousterhout professor computer science university california berkeley created tcl scripting language tk platform-independent widget toolkit proposed idea coscheduling ousterhout also led research group designed experimental sprite operating system first log-structured file system ousterhout author magic vlsi computer-aided design cad program received bachelor degree physics yale university 1975 ph.d. computer science carnegie mellon university 1980 ousterhout received grace murray hopper award 1987 work cad systems very-large-scale integrated circuits work inducted 1994 fellow association computing machinery ousterhout member national academy engineering 1994 ousterhout left berkeley join sun microsystems laboratories hired team join tcl development several years sun left co-founded scriptics inc. later renamed ajuba solutions january 1998 provide professional tcl development tools tcl team followed sun ajuba purchased interwoven october 2000 joined faculty stanford university 2008
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Programming language topics
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jack nicklaus greatest 18 holes major championship golf jack nicklaus greatest 18 holes major championship golf golf-simulation video game developed sculptured software published accolade beginning 1988 released amiga amstrad cpc apple ii atari st commodore 64 c64 ms-dos macintosh msx nintendo entertainment system nes pc-88 sharp x68000 1990 1991 game released hucard cartridge cd-rom formats u.s turbografx-16 foreign counterpart pc engine turbografx-16 versions game titled jack nicklaus turbo golf pc engine version titled jack nicklaus world golf tour cd-rom format game boy version released jack nicklaus golf 1992 first series golf games named golfer jack nicklaus followed jack nicklaus unlimited golf course design 1990 game features jack nicklaus favorite 18 golf holes put together single course includes holes augusta national golf club muirfield pebble beach golf links royal lytham st annes golf club old course st andrews two courses designed nicklaus also featured game castle pines colorado desert mountain arizona additionally game boy version includes muirfield village course several add-on disks released computer versions add additional courses game features two game modes stroke play skins multiplayer option allows maximum total four players able play player also compete selection eight different cpu players includes jack nicklaus image nicklaus also appears holes gives tips player jack nicklaus turbo golf turbografx-16 differs versions cd-rom format game five courses including castle pines courses previously featured game early add-on disks australian golf club royal troon golf club kemper lakes golf club st. creek golf club cd-rom version allows player take 360-degree look around courses nicklaus appears courses give advice hole hucard cartridge version jack nicklaus turbo golf includes one course australian golf club includes eight golfer rivals well jack nicklaus accolade began publishing jack nicklaus greatest 18 holes major championship golf 1988 longest title software product time release august 1989 versions released united kingdom commodore 64 pc versions amiga amstrad cpc atari st scheduled release autumn apple ii version released late 1989 1990 macintosh version published accolade nes version published konami released united states march 1990 united kingdom release came august 1991 versions also released msx pc-88 sharp x68000 u.s. turbografx-16 game released jack nicklaus turbo golf hucard cd-rom formats game also released turbografx-16 foreign counterpart pc engine cd-rom format pc engine version published title jack nicklaus world golf tour game hucard format retained original jack nicklaus greatest 18 holes major championship golf title jack nicklaus turbo golf foreign counterparts released 1990 1991 game boy version jack nicklaus golf released united states may 1992 published tradewest along unrelated game title super nes computer versions game received criticism slow load times generating new screen criticized computer version including off-disc copy protection scheme deemed difficult use critics favorably compared game leader board golfing game series praise given graphics amiga amstrad cpc commodore 64 versions amstrad action called cpc version beyond shadow doubt best golf sim ever cpc however magazine also wrote game would immediately appeal golf fans people played computer golf games stating limitations unfairly cripple game popularity – crime entertaining well-programmed sports sim cu amiga-64 praised amiga version gameplay critical minimal sounds putting agonisingly slow computer golfer opponent zzap 64 reviewed commodore 64 version criticized sound effects well blocky scenery unusual color schemes games machine reviewing cpc st versions criticized blocky scenery murky colors well simple sound effects poorly animated golfer sprites reviewing amiga version magazine praised digitized image jack nicklaus appears holes criticized rest graphics tom malcom .info reviewed commodore 64 version called graphics adequate sound abominable concluded game overall good choice malcom subsequently reviewed amiga version praised gameplay felt graphics could also wished option turn jack nicklaus advice hole stating slowed gameplay considerably bob wade amiga format praised sound tony hetherington amiga criticized bad putting controls called game perfectly playable competently programmed still considered bland amiga action praised game recommended considered leader board superior amiga user international recommended game people already purchased mean 18 similar golf game also accolade dan muse incider praised apple ii version new standard computer golf games best sports game period regarding image nicklaus appears holes muse wrote okay little corny like michael dashe macworld praised macintosh version graphics realistic gameplay variety courses nes turbografx-16 versions also criticized slow reanimation raze reviewed nes version stated easy gameplay fun play people rather alone mean machines criticized nes version blocky scenery stating hampered gameplay magazine also criticized golfer sprite average sound effects lack music concluded tedious golf sim die-hard fans genre take chance chicago sun-times reviewing one game versions wrote great golfing enthusiasts good new golf chip jonathan carter writing philadelphia daily news reviewed turbografx-16 cartridge version stated additional courses would nice although praised gameplay graphics gamepro reviewed turbografx-16 cd-rom version recommended game golf fans criticized slow reanimation stated game offer much distinguish golf games
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Computer architecture
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bigquery bigquery restful web service enables interactive analysis massive datasets working conjunction google storage serverless platform service paas may used complementarily mapreduce limited testing period 2010 bigquery generally available november 2011 google atmosphere conference april 2016 european users service suffered 12-hour outage may 2016 support announced google sheets bigquery provides external access dremel technology scalable interactive ad hoc query system analysis read-only nested data bigquery requires requests authenticated supporting number google-proprietary mechanisms well oauth
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Web technology
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jit spraying jit spraying class computer security exploit circumvents protection address space layout randomization aslr data execution prevention dep exploiting behavior just-in-time compilation used exploit pdf format adobe flash just-in-time compiler jit definition produces code data since purpose produce executable data jit compiler one types programs run no-executable-data environment jit compilers normally exempt data execution prevention jit spray attack heap spraying generated code produce exploit code jit idea dion blazakis used input program usually javascript actionscript typically contains numerous constant values erroneously executed code example xor operation could used jit transform bytecode native x86 code like attacker uses suitable bug redirect code execution newly generated code example buffer overflow use free bug could allow attack modify function pointer return address causes cpu execute instructions way unintended jit authors attacker usually even limited expected instruction boundaries possible jump middle intended instruction cpu interpret something else non-jit rop attacks may enough operations usefully take control computer continuing example jumping second byte mov instruction results inc instruction computer hardware allows jumping middle instruction includes x86 x86-64 arm although especially effective type hardware jit spraying works systems well protect jit spraying jit code disabled made less predictable attacker
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Computer security
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fido2 project fido2 project joint effort fido alliance world wide web consortium w3c whose goal create strong authentication solution web core fido2 consists w3c web authentication webauthn standard fido client authenticator protocol ctap fido2 based upon previous work done fido alliance particular universal 2nd factor u2f authentication standard taken together webauthn ctap specify standard authentication protocol protocol endpoints consist user-controlled cryptographic authenticator smartphone hardware security key webauthn relying party also called fido2 server web user agent i.e. web browser together webauthn client form intermediary authenticator relying party single webauthn client device may support multiple webauthn clients example laptop may support multiple clients one conforming user agent running laptop conforming user agent implements webauthn javascript api name implies client authenticator protocol ctap enables conforming cryptographic authenticator interoperate webauthn client ctap specification refers two protocol versions called ctap1/u2f ctap2 authenticator implements one protocols typically referred u2f authenticator fido2 authenticator respectively fido2 authenticator also implements ctap1/u2f protocol backward compatible u2f
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Computer security
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interrupt request pc architecture computer interrupt request irq hardware signal sent processor temporarily stops running program allows special program interrupt handler run instead hardware interrupts used handle events receiving data modem network card key presses mouse movements interrupt lines often identified index format irq followed number example intel 8259 family pics eight interrupt inputs commonly referred irq0 irq7 x86 based computer systems use two pics combined set lines referred irq0 irq15 technically lines named ir0 ir7 lines isa bus historically attached named irq0 irq15 newer x86 systems integrate advanced programmable interrupt controller apic conforms intel apic architecture apics support programming interface 255 physical hardware irq lines per apic typical system implementing support around 24 total hardware lines working personal computer hardware installing removing devices system relies interrupt requests default settings configured system bios recognized operating system default settings altered advanced users modern plug play technology reduced need concern settings also virtually eliminated manual configuration typically systems using intel 8259 pic 16 irqs used irqs 0 7 managed one intel 8259 pic irqs 8 15 second intel 8259 pic first pic master one directly signals cpu second pic slave instead signals master irq 2 line master passes signal cpu therefore 15 interrupt request lines available hardware newer systems using intel apic architecture typically 24 irqs available extra 8 irqs used route pci interrupts avoiding conflict dynamically configured pci interrupts statically configured isa interrupts early apic systems 16 irqs intel 8259 interrupt controllers pci interrupt lines routed 16 irqs using pir integrated southbridge easiest way viewing information windows use device manager system information msinfo32.exe linux irq mappings viewed executing cat /proc/interrupts using procinfo utility early ibm-compatible personal computers irq conflict common hardware error received two devices trying use interrupt request irq signal interrupt programmable interrupt controller pic pic expects interrupt requests one device per line thus one device sending irq signals along line generally cause irq conflict freeze computer example modem expansion card added system assigned irq4 traditionally assigned serial port 1 likely cause irq conflict initially irq 7 common choice use sound card later irq 5 used found irq 7 would interfere printer port lpt1 serial ports frequently disabled free irq line another device irq 2/9 traditional interrupt line mpu-401 midi port conflicts acpi system control interrupt sci hardwired irq9 intel chipsets means isa mpu-401 cards hardwired irq 2/9 mpu-401 device drivers hardcoded irq 2/9 used interrupt-driven mode system acpi enabled rare conditions two devices could share irq long used simultaneously solve problem later pci bus specification allows irq sharing additional support message signaled interrupts msi later revisions pci express physical interrupt lines uses msi exclusively
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Computer architecture
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radio link protocol radio link protocol rlp automatic repeat request arq fragmentation protocol used wireless typically cellular air interface wireless air interfaces tuned provide 1 packet loss vocoders mutually tuned sacrifice little voice quality 1 packet loss however 1 packet loss intolerable variants tcp something must done improve reliability voice networks carrying tcp/ip data rlp detects packet losses performs retransmissions bring packet loss .01 even .0001 suitable tcp/ip applications rlp also implements stream fragmentation reassembly sometimes in-order delivery newer forms rlp also provide framing compression older forms rlp rely upon higher-layer ppp protocols provide functions rlp transport ask air interface provide certain payload size instead air interface scheduler determines packet size based upon constantly changing channel conditions upcalls rlp chosen packet payload size right transmission fragmentation protocols 802.11b ip used payload sizes determined upper layers call upon mac create payload certain size protocols flexible rlp sometimes fail transmit deep fade wireless environment rlp payload size little 11 bytes based upon cdma is-95 network smallest voice packet size rlp headers must small minimize overhead typically achieved allowing ends negotiate variable 'sequence number space used number byte transmission stream variants rlp sequence counter small 6 bits rlp protocol ack-based nak-based rlps nak-based meaning forward-link sender assumes transmission got receiver naks out-of-order segment received greatly reduces reverse-link transmissions spectrally inefficient longer latency cellular networks transmit pipeline goes idle nak-based rlp must eventually retransmit last segment second time case last fragment lost reach .01 packet loss rate duplicate transmission typically controlled flush timer set expire 200-500 milliseconds channel goes idle concept rlp protocol invented phil karn 1990 cdma is-95 networks january 2006 ieee 802.20 specification uses one newest forms rlp cellular networks gsm cdma use different variations rlp umts lte protocol called rlc radio link control
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Internet protocols
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dshell dshell open source python-based forensic analysis framework developed u.s. army research laboratory md tool provides users ability develop custom analysis modules helps understand events cyber intrusion framework handles stream reassembly ipv4 ipv6 network traffic also includes geolocation ip-to-asn mapping connection additionally framework plug-ins designed aid understanding network traffic present results user concise useful manner since dshell written entirely python code base customized particular problems modifying existing decoder extract different information existing protocols u.s. army research laboratory arl released version dshell github social coding website december 17 2014 100 downloads 2,000 unique visitors 18 countries publicly released dshell small select community users several government organizations users could use tool tool find exact information needed network data including looking names reassembled website requests decoded malware traffic arl chose release dshell github sharing world created security teams gaining another specialized tool keep networks secure furthermore increasing security internet whole increasing number skilled eyes looking bugs potential improvements throughout code 2014 nasa released 1,000 dshell agencies national security agency national guard air force research laboratory joined shortly following year github chosen dshell allows members easily download software code store edits provide mechanism offer feedback original designer additionally rolling enhancements official version make easier share software across organizations bypassing constant emailing sending cds june 2016 users created 11,000 copies tool offered approximately 62 suggested modifications original software additional modules within dshell framework accessed increase network security however ability rapidly develop share analytical modules core strength framework
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Computer security
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internet imaging protocol internet imaging protocol iip internet protocol designed international imaging industry association iip built top http communicate images metadata took inspiration flashpix image architecture emerged tackle problem image sizes resolution growing faster internet bandwidth difficult quickly browse high quality images web browsers iip allows detail fetched user needs whole data file downloaded practically defines software fetches image tiles server includes scale image small overview image retrieved initially zooming panning carried fetching higher resolution image tiles server means size image viewed web without downloading iip also makes possible use variety viewer software whereas systems may force use one server file format one viewer iip currently version 1.05 actively developing
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Internet protocols
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meteo system meteo system machine translation system specifically designed translation weather forecasts issued daily environment canada system used 1981 30 september 2001 environment canada translate forecasts issued french province quebec english issued english canadian provinces french since competitor program replaced meteo system open governmental bid system developed john chandioux often mentioned one success stories field machine translation meteo system operational use environment canada 1982 2001 stems prototype developed 1975-76 taum group known taum-meteo initial motivation develop prototype junior translator came taum ask help translating weather bulletins environment canada since official communications emanating canadian government must available french english official languages act 1969 weather bulletins represent large amount translation real time junior translators spend several months producing first draft translations revised seniors difficult tedious job specificities english french sublanguages used rewarding lifetime bulletin 4 hours taum proposed build prototype mt system environment canada agreed fund project prototype ready months basic integration workflow translation source target bulletins travelled telex lines time mt happened mainframe computer first version system meteo 1 went operation control data cdc 7600 supercomputer march 1977 chandioux left taum group manage operation improve taum group embarked different project taum-aviation 1977–81 benoit thouin made improvements initial prototype subsequent year turned operational system three years meteo 1 demonstrated feasibility microcomputer-based machine translation satisfaction canadian government translation bureau public works government services canada meteo 1 formally adopted 1981 replacing junior translators workflow need high quality translation revision step done senior translators maintained quality measured percentage edit operations inserting deleting word counts 1 replacing 2 mt results reached 85 1985 time mt part still implemented sequence q-systems q-systems formalism rule-based sllp specialized language linguistic programming invented alain colmerauer 1967 postdoc coopérant taum group later invented prolog language 1972 returning france becoming university professor marseille-luminy engine q-systems highly non-deterministic manipulated data structures ways simple without types string number chandioux encountered limitations efforts raise translation quality lower computation time point could run microcomputers 1981 chandioux created new sllp metalanguage linguistic applications based basic algorithmic ideas q-systems deterministic offering typed labels tree nodes following advice bernard vauquois colmerauer created gram r developed microcomputers 1982 could start developing gram r new system translating weather bulletins high-end cromemco microcomputer meteo 2 went operation 1983 software ran 48kb central memory 5mb hard disk paging meteo 2 first mt application run microcomputer 1985 system nothing left initial prototype officially renamed meteo translated 20 million words per year english french 10 million words french english quality 97 typically took 4 minutes bulletin english sent winnipeg come back french mt human revision 1996 chandioux developed special version system meteo 96 used translate weather forecasts different kinds bulletins issued us national weather service 1996 summer olympics atlanta last known version system meteo 5 dates 1997 ran ibm pc network windows nt translated 10 pages per second able fit 1.44mb floppy disk
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Computational linguistics
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compiler description language compiler description language cdl programming language based affix grammars similar backus–naur form bnf notation designed development compilers limited capabilities control flow intentionally benefits limitations twofold one hand make possible sophisticated data control flow analysis used cdl2 optimizers resulting extremely efficient code benefit foster highly verbose naming convention turn leads programs great extent self-documenting language looks bit like prolog surprising since languages arose time work affix grammars opposed prolog however control flow cdl deterministically based success/failure i.e. alternatives tried current one succeeds idea also used parsing expression grammars cdl3 third version cdl language significantly different previous two versions original version designed cornelis h. a. koster university nijmegen emerged 1971 rather unusual concept core typical programming language source translated machine instructions canned sequences instructions represent core basic abstractions given language supports primitives additions numbers copying variables cdl1 lacks core responsibility programmer provide primitive operations form turned machine instructions means assembler compiler traditional language cdl1 language concept primitives concept data types apart machine word abstract unit storage necessarily real machine word evaluation rules rather similar backus–naur form syntax descriptions fact writing parser language described bnf rather simple cdl1 basically language consists rules rule either succeed fail rule consists alternatives sequences rule invocations rule succeeds alternatives succeeds tried sequence alternative succeeds rule invocations succeed language provides operators create evaluation loops without recursion although strictly necessary cdl2 optimizer achieves effect shortcuts increase efficiency otherwise recursive evaluation basic concept apart obvious application context-free grammar parsing cdl also well suited control applications since lot control applications essentially deeply nested if-then rules cdl1 rule evaluated act data unspecified type ideally data changed unless rule successful side effects failure causes problems although rule may succeed rule invoking might still fail case data change take effect fairly easy albeit memory intensive assure behavior data dynamically allocated stack rather hard static data often case cdl2 compiler able flag possible violations thanks requirement direction parameters input output input-output type rules fail test predicate fail function action side effect predicate action side effect test function must specified programmer rule evaluation based calling simpler simpler rules bottom primitive rules actual work cdl1 surprising primitives provide rules need addition program create rule two input parameters one output parameter output set sum two inputs code cdl compiler uses code strings conventions refer input output variables simply emits needed describe adding rule using assembly need assembler translate cdl compiler output machine code describe primitive rules macros cdl terminology pascal c need pascal c compiler run cdl compiler lack core primitives painful write snippet code even simplest machine instruction operation hand gives great flexibility implementing esoteric abstract primitives acting exotic abstract objects 'machine word cdl like 'unit data storage reference kind data stored additionally large projects made use carefully crafted libraries primitives replicated target architecture os allowing production highly efficient code get feel language small code fragment adapted cdl2 manual primitive operations defined terms java c complete program must define java array items elsewhere cdl2 appeared 1976 kept principles cdl1 made language suitable large projects introduced modules enforced data-change-only-on-success extended capabilities language somewhat optimizers cdl2 compiler especially cdl2 laboratory ide cdl2 world class time one feature cdl2 laboratory optimizer almost unique perform optimizations across compilation units i.e. treating entire program single compilation cdl3 recent language gave open-ended feature previous cdl versions provides primitives basic arithmetic storage access extremely puritan syntax earlier cdl versions number keywords symbols run single digits also relaxed basic concepts expressed syntax rather explicit semantics addition data types introduced language commercial mbp cobol cobol compiler pc well mprolog system industrial strength prolog implementation ran numerous architectures ibm mainframe vax pdp-11 intel 8086 etc os-s dos/os/cms/bs2000 vms/unix dos/windows/os2 latter particular testimony cdl2 portability programs written cdl compilers least one commercial gui application developed maintained cdl application dental image acquisition application owned dexis dental office management system also developed cdl software mephisto iii chess computer written cdl2
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Programming language topics
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j2ee management j2ee management specification java specification request jsr-77 standardization j2ee server management j2ee management specification abstracts manageable parts j2ee architecture defines interface accessing management information helps system administrators integrate j2ee servers system management environment also helps application developers create management tools scratch goal jsr 77 abstract fundamental manageable aspects j2ee architecture provide well defined model implementing instrumentation information access addition specification defines standardized api inter-operating j2ee components participate monitoring control platform ’ resources implementation jsr-77 enterprise applications done application server done web container j2ee management model specification attributes operations architecture managed objects required compliant j2ee platform implementations model designed interoperable variety industry standard management systems protocols management ejb mejb component provides interoperable remote access model j2ee application components compliant implementations must support mejb component specification also provides standard mappings model cim/wbem common information model cim snmp management information base mib implementation support snmp cim/wbem optional latest version jsr 1.1 released 08 may 2006
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Programming language topics
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world reuse repair recycling association world reuse repair recycling association wr3a business consortium dedicated reform trade e-waste wr3a inspired fair trade organizations wr3a fair trade association tradename fair trade recycling reserved 2013 established improve export markets surplus electronics e-waste defend biased reporting racial profiling wr3a conceived 2006 following visit china group including usa electronics recycler american retroworks inc. university california davis recycling program director seattle recycler zero-export policy group inspired visit three china semi knock factories factories purchased usa computer monitors still functional crts crts knocked bare tube inserted new tv monitor case complete new tuner board etc wr3a founders observed western journalists reporting purchase import used crts invariably described primitive wire burning operations rather re-manufacturers often contract manufacturers originally assembled brand new crt monitors rebuilt second-hand crts usa crt refurbishing factory video display corp tucker georgia wr3a proposed form coalition usa companies export functional crt monitors directly reuse factories removing imploded damaged screen-burned older non-compliant raster e.g trinitron crts loads destined crt factories usa companies remove recycle bad 1/3 crts would benefit higher prices chinese factories would bypass sorting villages guiyu wr3a swamped orders asian factories year chinese government took new crt manufacturing capacity worldwide 1990s eventually opposed import used crts many skd factory owners relocated businesses countries indonesia malaysia thailand others relocated used monitor sourcing operations hong kong vietnam trucking crts overland chinese factories period several anti-globalist ngos began campaign end trade used electronics especially crts cbs 60 minutes economist businessweek others ran reports claiming 80 displays exported reused burned copper primitive scrapyards source 80 dumping claim later retracted eventually reuse operations asia turned re-export africa used local sources urban asian cities used crts used remanufacturing new tv monitor displays decline purchases used displays usa 2011 wr3a recognized organizational conflicts cooperative suppliers competing declining market organization refined mission 2013 emphasize anti-defamation overseas refurbishing companies promoted used electronics exports peer-reviewed fair trade agreements importers used equipment africa asia latin america consider organization defender tech sector refurbishers wr3a remains dedicated principle used computer exports outlawed outlaws export used computers organization members south america africa asia north america europe dedicated defending legitimate used electronics exporters organization considers false defamatory declarations e-waste toxics externalization 2015 2017 2018 wr3a led visits agbogbloshie district central accra bringing journalists al jazeera independent smithsonian others meet dagbani speaking translators visit led journalists discredit allegations agbogbloshie largest e-waste dump world former wetland outskirts city received hundreds sea containers full junk electronics wr3a found credible evidence dumping site exaggerated accra metropolitan association representatives interested relocating economic refugees develop property three months forced evictions used electronics processed site shown delivered carters wheelbarrows consist devices vcrs imported decades previously wr3a provided reporters world bank statistics showing domestic ghana generation accounted e-waste observed ghana recorded organization interviews ghana tech sector representatives uploaded youtube wr3a september 2013 wr3a adapted tradename fair trade recycling trademark registered uspto registered supplemental certification may 26 2015 organization claim recognized fairtrade one word april 2013 wr3a held fair trade recycling summit middlebury college vermont summit brought together researchers memorial university canada pontificia universidad catholica de peru university southern california usa massachusetts institute technology mit representatives usa international trade office basel convention secretariat interpol several used electronics importers africa asia latin america group deliberated beneficial development emerging markets electronics reuse repair labelled tinkerer blessing yuzo takahashi 2000 technology history network tinkerers. role electronics repair reverse engineering development contrasted so-called resource curse economic development natural resource exploitation middlebury students presenters discussed whether balanced approach recycling secondary materials may warranted follow meeting wr3a interpol held july 2013 november 2013 interpol announced new research program study used electronics trade continuing arrests african importers project eden debate fair trade recycling advocates anti-export organization basel action network profiled usa today september 26 2013 discovery magazine nih 2006 july 2012 memorial university newfoundland canada announced 5-year research project study map routes used electronics weee e-waste exports wr3a partner research grant along researchers universities peru california first year group document efforts develop fair trade recycling model mexico see npr pbs ap coverage research possible application model peru bangladesh china wr3a formerly adapted registered tradename fair trade recycling 2012 wr3a collaborated massachusetts institute technology publication mit january 2012 study e-waste generation exports wr3a provided researchers detailed reconciliations 3 years exports wr3a members mit compared wr3a data corroborating data isri usepa basel secretariat ghana nigeria studies may 2011 wr3a interviewed part e-waste german news magazine zdf.kultur investigated assumptions african imports primitive linked exports egypt green revolution march 2011 wr3a profiled motherboard.tv organization case reduced exports used electronics stewards unintended consequences october 2010 wr3a announced partnership basel action network reduce unnecessary breakage destruction working computer monitors california california sb20 laws followed report critical california cancellation policies published sacramento bee july 19 2010 july 30 2010 discovery news presented analysis contrasting wr3a fair trade engagement approach basel action network ban trade restriction approach abstained choosing sides. may 15 2009 national public radio npr program living earth profiled one wr3a members women cooperative tv repair recycling mexico january 2009 organization presented statistics film keynote address ces 2009 las vegas statistics demonstrated rate growth internet access much higher countries low incomes logically unlikely growth achieved new computers wr3a also presented film reuse refurbishing operations demonstrate proper recycling practices best available practices ten countries wr3a contracted consultant us environmental protection agency july 2008 publication electronic waste management united states
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Computer security
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.ds store apple macos operating system .ds_store file stores custom attributes containing folder position icons choice background image name abbreviation desktop services store reflecting purpose created maintained finder application every folder functions similar file desktop.ini microsoft windows starting full stop period character hidden finder many unix utilities internal structure proprietary file .ds_store created directory folder accessed finder application even remote file systems mounted servers share files example via server message block smb protocol apple filing protocol afp remote file systems however could excluded operating system settings permissions although primarily used finder files envisioned general-purpose store metadata display options folders icon positions view settings example mac os x 10.4 tiger later .ds_store files contain spotlight comments folder files comments also stored extended file attributes finder read earlier apple operating systems finder applications created similar files root volume accessed including foreign file systems collecting settings files volume instead separate files respective folder complaints many users prompted apple publish means disable creation files remotely mounted network file systems however instructions apply local drives including usb flash drives although workarounds mac os x 10.5 .ds_store files visible remote filesystems .ds_store files impose additional burdens revision control process inasmuch frequently changed therefore appear commits unless specifically excluded .ds_store files included archives zip created os x users along hidden files directories .ds_store files known adversely affect copy operations multiple files selected file transfer copy operation retroactively cancel progress upon reaching .ds_store file forcing user restart copy operation beginning 2015 .ds_store file led leakage tcl corporation admin portal
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Operating systems
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hp 200lx hp 200lx palmtop pc f1060a f1061a f1216a also known project felix personal digital assistant introduced hewlett-packard august 1994 often called palmtop pc notable minor exceptions ms-dos-compatible computer palmtop format complete monochrome graphic display qwerty keyboard serial port pcmcia expansion slot input accomplished via small qwerty-keyboard numeric keypad enclosed clamshell-style case less 25 size standard notebook computer palmtop runs 30–40 hours two size aa alkaline ni-cd rechargeable cells charge batteries ni-cd nimh via 12v dc wall adapter hp 200lx intel 80186 compatible embedded central processing unit named hornet runs ~7.91 megahertz upgraded overclocked 15.8 mhz 1 2 4 mb memory 640 kb ram rest used expanded memory ems memory-based storage space after-market updates bring memory chips 64 mb frees pcmcia slot modem ethernet card use silicom accton 2212/2216 netgear fa411 sohoware nd5120 network cards compatible ibm pc/xt compatible running ms-dos 5.0 rom hp 200lx run virtually program would run full-size pc compatible computer long code written intel 8086 8088 80186 cpu run using cga graphics also run programs written 80286 cpu provided require use protected mode 16-bit pcmcia type ii expansion slot supports 5 v 150 maximum sir compatible infrared port full serial port proprietary mini connector space constraint reasons built-in software suite runs rom includes lotus 1-2-3 release 2.4 spreadsheet calendar phone book terminal capable scientific/business calculator among applications large compactflash storage card serial mouse even microsoft windows 3.0 run palmtop running windows limited hardware maximum version could run windows 3.0 real mode however word 1.x excel 2.x windows would run since could run real mode allowing authoring ms office format-compatible files 640×200 resolution cga compatible 4-shade gray-scale lcd screen back light electroluminescent technology back light installation available third party since 2004 keen eyesight still required use small palmtop effectively without resorting using 2× 4× zoom modes true cga displays allow redefinable fonts text mode support hardware code page 437 hp 95lx supports code page 850 instead starting hp 100lx lx series even supports user-switchable text mode rom fonts code page 437 850 well software-definable ram fonts codepages 437g 437t 852 866 via keybez lotus 1-2-3 internally uses lotus international character set lics characters translated code page 850 display printing purposes hp 100lx palmtop pc f1020a 1 mb f1022a 2 mb model also known project cougar direct predecessor 200lx released 1993 available international english u.s. english french german spanish variants localized keyboard messages almost including hornet cpu ms-dos 5.0 earlier built-in application versions hp palmtop fx variant hp 100lx 2 mb flashable memory 1993 fat flash disk images could created written drive f special flashdsk.exe utility according one source developed korean insurance company hp 200lx aia 2 mb double-speed variant hp 200lx manufactured insurance company american international assurance aia hp 1000cx palmtop pc f1203a 1 mb march 1995 f1222a 2 mb model february 1997 also known project puma economy version 200lx hornet cpu without built-in software except ms-dos 5.0 operating system rom widespread use among example coca-cola warehouse managers loaded logistics software onto machine black clamshell 200lx dark green casing hp omnigo 700lx communicator plus f1206a codenamed columbia project hp calculator branch singapore hp omnigo 700lx essentially 2 mb hp 200lx including hornet cpu redesigned piggyback nokia 2110 gsm mobile telephone wireless mobility hp 200lx motherboard factory-modified support second pcmcia slot nokia data card owing relatively large size nokia telephone hp omnigo 700lx large pebble-shaped casing making handheld phone attached announced late 1995 part plans collaboration hp nokia shipment starting march 1996 production hp omnigo 700lx ceased nokia 2110 mobile telephone rendered obsolete later telephones device seen forerunner first smartphone nokia communicator 9000 hp 95lx palmtop pc f1000a 512 kb f1010a 1 mb model introduced basic design april 1991 known internally project jaguar nec v20 cpu enhanced intel 8088 clone intel 80186 instruction set compatibility additional intel 8080 emulation mode running 5.37 mhz hampered running pc applications quarter-cga resolution lcd screen mda compatible instead cga graphics chip hp 95lx part displayed graphics special lx graphics mode ran ms-dos 3.22 lotus 1-2-3 release 2.2 built also included cr2032 battery memory backup aa mains ran hp omnigo 100 organizer plus f1305a/f1310a designed sophisticated successor lx series incorporated hp-12c calculator functionality gui based controlled pen input keyboard however lacked versatility running unmodified dos programs normal operation mode dos-based pen/geos 2.1 graffiti handwriting recognition running datalight rom-dos 6.22 widely accepted calculator replacement palm pocket pcs became acceptable pdas equipped 1 mb ram based vadem vg230/v5h highly integrated system controller 16 mhz nec v30hl cpu instruction set compatible intel 80186 although product line discontinued hp order introduce windows ce product line starting hp 300lx strong interest hardware continued last palmtop hp ran ms-dos operating system much software desktop pcs came useful bundle software including 1-2-3 quicken compared machines windows-based operating systems ce dos programs compact efficient programs software carousel many applications programs could loaded third-party upgrades repairs renovations available maintain extend device small size hp 200lx popular japan much demise prompted open-source initiative design market amd elan sc400-based replacement fill place 'morphy one club organization created blueprints device prototype ever built reasons remain unclear argue scam scheme hundreds people lost deposits placed new palmtop advance project leaders argued key electronic components unavailable due strong demand mobile telephone manufacturing industry many easter eggs built hp 200lx known ones listed follows easter egg hp 200lx built game lair squid startup screen game user types word gallery gallerie french palmtop siegergalerie german palmtop galeria spanish palmtop he/she placed part maze contains photographs primary software developers worked hp 200lx user may exit gallery exiting door end corridor software developers photographs listed starting left right left right follows last panel right corridor contains thank message photographs developers described a-maze-ing easter egg hp 200lx self test mode palmtop powered user may press esc start self test mode cursor display option pressing enter 14 times step various screens user comes screen example text form limerick poem poem follows easter egg hp 200lx self test mode palmtop powered user may press esc start self test mode cursor display option pressing ctrl enter holding alt pressing enter 13 times user comes cryptic poem relating business issues faced software development team poem follows easter egg hp 200lx self test mode palmtop powered user may press esc start self test mode cursor display option pressing ctrl enter holding shift pressing enter 13 times user comes allegorical poem history future hp lx palmtops poem follows note project names hp 95lx hp 100lx hp 200lx 'jaguar 'cougar 'felix respectively 'felix first lx include quicken easter egg built system manager hp 200lx 'easter egg probably development tool easter egg case user may display function first pressing blue ... key start 'more applications user may hold alt pressing f9 4 times followed f10 long alt key held user observe columns data system manager compliant .exm programs registered system manager along arcane program information hp 200lx includes undocumented calculator application named hexcalc written andrew gryc provides arithmetical logical operations binary octal decimal hexadecimal system utility added applications menu entry following fields
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Computer architecture
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distributed.net distributed.net distributed computing effort attempting solve large scale problems using otherwise idle cpu gpu time governed distributed computing technologies incorporated dcti non-profit organization u.s. tax code 501 c 3 distributed.net working rc5-72 breaking rc5 72-bit key ogr-28 searching optimal 28-mark golomb ruler rc5-72 project pace exhaust keyspace 150 years although project end whenever required key found problems part series ogr part infinite series rc5 eight unsolved challenges rsa security although may 2007 rsa security announced would longer providing prize money correct key secret key challenges distributed.net decided sponsor original prize offer finding key result 2001 distributed.net estimated throughput 30 tflops 2009 throughput estimated much higher coordinated effort started february 1997 earle ady christopher g. stach ii hotjobs.com new media labs effort break rc5-56 portion rsa secret-key challenge 56-bit encryption algorithm 10,000 usd prize available anyone could find key unfortunately initial effort suspended result syn flood attacks participants upon server new independent effort named distributed.net coordinated jeffrey a. lawson adam l. beberg david c. mcnett along several others would serve board operate infrastructure late march 1997 new proxies released resume rc5-56 work began enhanced clients cow head selected icon application project mascot rc5-56 challenge solved october 19 1997 250 days correct key 0x532b744cc20999 plaintext message read unknown message time move longer key length rc5-64 challenge solved july 14 2002 1,757 days correct key 0x63de7dc154f4d039 plaintext message read unknown message things better left unread search ogrs order 24 25 26 27 completed distributed.net 13 october 2004 25 october 2008 24 february 2009 19 february 2014 respectively dnetc file name software application users run participate active distributed.net project command line program interface configure available wide variety platforms distributed.net refers software application simply client volunteers running 32-bit windows ati/amd stream enabled gpus contributed processing power rc5-72 project volunteers running 64-bit gnu/linux contributed processing power ogr-28 project portions source code client publicly available although users permitted distribute modified versions distributed.net rc5-72 ogr-28 projects available boinc client moo wrapper yoyo home projects respectively recent years work rc5-72 project submitted clients run gpu modern graphics cards although project already underway almost 6 years first gpus began submitting results march 2018 gpus represent 78 completed work units complete nearly 93 work units day
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Computer security
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comparison windows vista windows xp page comparison windows vista windows xp windows xp windows vista differ considerably regards security architecture networking technologies management administration shell user interface mobile computing windows xp suffered criticism security problems issues performance vista received criticism issues performance product activation another common criticism vista concerns integration new forms drm operating system user account control uac security technology windows vista faces backward compatibility problems many games utility programs work windows xp july 2008 2,000 applications specifically carried 'vista compatibility logo although majority applications without logo run without problems number low compared number programs currently work xp either natively simulation modality initial performance tests demonstrated windows xp outperforms vista several productivity areas file copy operations speculated one area vista performs better xp test run crn test center 1.25 gb file copied network share desktop xp took 2 minutes 54 seconds vista sp1 took 2 minutes 29 seconds vista implementation file copy arguably complete correct file register transferred completely transferred windows xp file completed dialogue box displayed prior file actually finishing copy transfer file completing dialogue displayed cause issue storage device ejected prior file successfully transferred copied windows xp due dialogue box premature prompt another test performed tom hardware january 2007 applications unreal tournament 2004 graphics benchmarking suite specviewperf 9.03 suffered heavily lack support opengl graphics library vista reached conclusion windows vista clearly great new performer comes executing single applications maximum speed hand find evidence windows vista desktop window manager dwm consumes energy windows xp window manager tests performed computer 2.93 ghz intel core 2 extreme x6800 processor 2× 1024 mb ddr2-800 ram radeon x1900xtx iceq3 graphics card 150 gb western digital wd1500adfd hard drive gigabyte ga-965p-dq6 motherboard scientific paper performance evaluation recent windows operating system performance concludes windows vista n't provide better overall performance high-end computer system compared windows xp performance improvements seen memory management graphics display parts os equal lower performance windows xp low-end computer system windows xp outperforms windows vista tested areas windows os network performance depends packet size used protocol however general windows vista compared windows xp shows better network performance particularly medium-sized packets security top priority windows vista development windows xp every user set administrator default unless added computer management result home users ran software administrator access however left users unwittingly open potential security threats hacking malware downloads large amount existing software ’ run well standard user due developers implementing principle least privilege design testing example many poorly written applications often assume incorrectly read write access entire filesystem system registry denying application access assumed rights cause application fail sometimes person logged standard user windows xp ca n't perform user-specific tasks changing system clock calendar changing computer time zone changing computer power management settings due so-called lua bugs user account control windows vista improves limiting application software standard user privileges administrator authorizes increase privilege level way uac prevents users making inadvertent changes system settings locks computer prevent unauthorized applications installing performing malicious actions windows vista able work around many lua bugs third party applications file registry virtualisation feature well application compatibility shims internet explorer 7 protected mode utilizes user account control isolate ie applications prevent writing content location except temporary internet files folder internet explorer 7 available xp support protected mode xp windows vista also includes windows defender spyware scanning removal tool also available windows xp free enterprise ultimate editions windows vista include bitlocker drive encryption aims help protect data case stolen devices vista implements address space layout randomization makes considerably difficult malicious code exploit return-to-libc attacks previous versions windows particularly 64-bit systems furthermore vista implements heap management enhancements make much difficult carry buffer overflow attacks 64-bit editions windows vista require kernel-mode drivers digitally signed initially making difficult rootkits install alureon managed overcome obstacle 2010 subverting master boot record firewall vista rewritten allowing outbound well inbound traffic blocked luna default visual style windows xp available three color schemes blue default olive green silver windows xp media center edition comes royale default theme editions windows vista default theme windows aero aero offers translucent window effects well live thumbnails animated transitions flip 3d however requires compatible graphics card wddm driver directx 9 support 32-bit color otherwise windows vista displayed using windows vista basic visual style
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Operating systems
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coccinella software coccinella latin coccinella ladybird free open-source cross-platform client xmpp/jabber-instant messaging-protocol software written tcl/tk language runs bsd linux mac os x solaris windows platforms support tcl/tk mats bengtsson published 1999 name whiteboard renamed coccinella 2003
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Internet protocols
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javafx script javafx script scripting language designed sun microsystems forming part javafx family technologies java platform javafx targeted rich internet application domain competing adobe flex microsoft silverlight specializing rapid development visually rich applications desktop mobile markets javafx script works integrated development environments netbeans eclipse intellij idea javafx released gnu general public license via sun sponsored openjfx project javafx script used called f3 form follows function f3 primarily developed chris oliver became sun employee acquisition seebeyond technology corporation september 2005 name changed javafx script became open sourced javaone 2007 javafx 1.0 released december 4 2008 september 10 2010 oracle announced javaone javafx script would discontinued although javafx api would made available languages java virtual machine september 27 2010 stephen chin announced visage declarative user-interface language based javafx script enhancements recently original f3 programming language process resurrected enhanced javafx script compiled statically typed declarative scripting language java platform provided automatic data-binding mutation triggers declarative animation using expression language syntax code blocks potentially yield values standard javafx apis supported retained mode vector graphics video playback standard swing components although f3 began life interpreted language prior first preview release q3 2008 javafx script shifted focus predominantly compiled interpreted javafx script still possible via jsr 223 'scripting java bridge built top java platform easy use java classes javafx script code compiled javafx script able run platform recent java runtime installed javafx script declarative syntax constructing user interfaces contrasts sharply verbose series method calls required construct equivalent interface swing directly simple hello world program javafx script shows following window/frame program also written way
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Programming language topics
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ios version history ios mobile operating system developed apple inc. iphone ipad ipod touch updates ios released itunes software since ios 5 via over-the-air software updates announcement ios 5 june 6 2011 usb connection itunes longer needed activate ios devices data synchronization happen automatically wirelessly apple icloud service major new ios releases announced yearly apple worldwide developers conference wwdc usually released september year usually coinciding release new iphone models recent stable release ios 12.4 released july 22 2019 june 3 2019 wwdc apple announced ios 13 new features include limited dark interface reworks reminders app redesign maps app recent ios 13 beta release ios 13.0 beta 7 released august 15 2019 june 2007 saw official release eventually became ios – concurrently first iphone ios official name official release iphone software development kit iphone sdk march 6 2008 apple marketing simply stated iphone ran version mac os x made specifically iphone ios introduced named iphone os officially renamed ios june 7 2010 announcement introduction ipad introduction ipad existence ipod touch meant iphone longer device run mobile operating system ios 4 first major ios release reflected name change apple licensed ios trademark cisco systems apple concurrently provides version ios comparable model iphone ipod touch usually devices released calendar year iphone users receive software updates free ipod touch users paid 2.0 3.0 major software updates ios 4 apple longer charges money ipod touch updates apple announced iphone os 1 iphone keynote january 9 2007 released public alongside original iphone june 29 2007 official name given initial release apple marketing literature simply stated iphone runs version apple desktop operating system os x release iphone os 1.1 brought support ipod touch 1st generation iphone os 1.1.5 final version iphone os 1 became unsupported 18 may 2010.what apple announce prototype code name acorn os looked like ipod classic style= background ececec padding:0 0.5em colspan= 5 |table versions iphone os 1.0.x
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Operating systems
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tricentis tosca tricentis tosca software testing tool used automate end-to-end testing software applications developed tricentis tricentis tosca combines multiple aspects software testing test case design test automation test data design generation analytics test guis apis business perspective two frequently-noted technologies used tricentis tosca related model-based testing risk-based testing instead using scripting test automation tricentis tosca applies model-based testing approach creates model application test technical details application test test case logic test data saved separately joined together test execution time element application test changes technical details updated central model since test cases inherit model various test cases test updated element need modified manually reflect change based risk assessment application test ’ requirements tricentis tosca uses risk-based test design suggest effective test cases identify risk contribution test cases also uses variety methodologies equivalence partitioning boundary testing combinatorial methods linear expansion try minimize number test cases increasing risk coverage tests executed tool aggregates risk coverage business technical compliance perspectives tricentis tosca features technologies gui testing api testing mobile testing service virtualization test data design generation business intelligence data warehouse testing exploratory testing sap-certified integration sap solutions used automate testing sap technologies sap s/4hana sap fiori 2.0 successfactors sap crm concur technologies sap ariba sap business information warehouse
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Web technology
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glove machine learning glove coined global vectors model distributed word representation model unsupervised learning algorithm obtaining vector representations words achieved mapping words meaningful space distance words related semantic similarity training performed aggregated global word-word co-occurrence statistics corpus resulting representations showcase interesting linear substructures word vector space developed open-source project stanford log-bilinear regression model unsupervised learning word representations combines features two model families namely global matrix factorization local context window methods glove used find relations words like synonyms company product relations zip codes cities etc also used spacy model build semantic word embeddings/feature vectors computing top list words match distance measures cosine similarity euclidean distance approach also used word representation framework online offline systems designed detect psychological distress patient interviews
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Computational linguistics
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metasan metasan cross-platform storage area network san management software developed sold tiger technology product ceased developed company 2014 however supported end 2016. metasan enables one share one physical virtual disk devices multiple hosts using fibre channel iscsi ethernet infiniband interconnect every computer participating san could read write storage volume folder time metasan file system distributed lock manager existing ntfs hfs+ file systems hardware agnostic worked off-the-shelf storage networking components offered per-node bandwidth control aimed enable fair distribution available storage bandwidth cross-platform setup metasan provided file-system translation services allowed mac windows linux workstations transparently access non-native volumes arbitrate accesses shared storage device one computer elected master san computer became metadata controller mdc computers clients san communicated sent metadata requests mdc lan request acknowledged clients could access storage device directly metasan setup member san could act mdc default first computer boot became mdc possible define priorities assign dedicated computer task metasan superseded tiger store http //www.tiger-technology.com/products/tiger-series/tiger-store/
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Computer file systems
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hacking tool hacking tool program designed assist hacking piece software used hacking purposes another example hacking tool computer worm malicious programs detect vulnerabilities operating systems worms however malicious nachi worms actually fixed operating system vulnerabilities downloading installing security patches microsoft website although much said threats linux system exist could increase future one biggest threats linux system given so-called rootkits programs special privileges able hide presence system administrator
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Computer security
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tanzania zanzibar international register shipping tanzania zanzibar international register shipping tzirs body appointed tanzania zanzibar government register ships tanzanian flag
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Databases
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paping paping pronounced pah ping computer network administration utility used test reachability host internet protocol tcp/ip network measure time takes connect specified port name play word ping another computer network administration utility icmp used identify operating system remote machine sometimes blocked icmp blocked ping used identify service responding publicly available services must keep relevant tcp udp ports open paping attempt make connections ports determine service responding similar utilities nmap allow range ports scanned however allow repetitively scan ports paping operates attempting connect internet protocol tcp/ip port target process measures time taken connection established records connection failures results test printed form statistical summary connections made including minimum maximum mean connection times paping cross-platform software currently supporting windows linux april 2013 project appears abandoned new fixes versions produced following sample output paping en.wikipedia.org tcp/ip port 80 http linux host
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Computer security
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ipad 1st generation first-generation ipad tablet computer designed marketed apple inc. first ipad line device features apple a4 processor 9.7 touchscreen display certain variants capability accessing cellular networks using ios operating system ipad play music send receive email browse web functions include ability play games access references gps navigation software social network services enabled downloading apps device announced unveiled january 27 2010 media conference april 3 2010 wi-fi variant device released united states followed release wi-fi cellular variant april 30 may 28 released australia canada france japan italy germany spain switzerland united kingdom device received primarily positive reviews various technology blogs publications reviewers praised device wide range capabilities labelled competitor laptops netbooks aspects criticized including closed nature operating system lack support adobe flash multimedia format first 80 days three million ipads sold launch ipad 2 apple sold 15 million ipads march 2 2011 apple announced ipad 2 reduced price first-generation ipad apple co-founder steve jobs stated 1983 speech company ’ apple ’ first tablet computer newton messagepad 100 introduced 1993 led creation arm6 processor core acorn computers apple also developed prototype powerbook duo-based tablet penlite decided sell order avoid hurting messagepad sales apple released several newton-based pdas final one messagepad 2100 discontinued 1998 apple reentered mobile-computing market 2007 iphone smaller yet announced ipad featuring camera mobile phone pioneered multitouch finger-sensitive touchscreen interface apple ’ ios mobile operating system late 2009 ipad release rumored several years speculation mostly talked “ apple ’ tablet ” specific names included itablet islate actual name reportedly homage star trek padd fictional device similar appearance ipad ipad announced january 27 2010 jobs apple press conference yerba buena center arts san francisco jobs later said apple began developing ipad iphone temporarily shelved effort upon realizing ideas would work well mobile phone ipad ’ internal codename k48 revealed court case surrounding leaking ipad information launch apple began taking pre-orders ipad us customers march 12 2010 major change device announcement available pre-order change behavior side switch sound muting screen rotation lock wi-fi version ipad went sale united states april 3 2010 wi-fi 3g version released april 30 3g service ipad united states provided initially sold two prepaid contract-free data plan options one unlimited data 250 mb per month half price june 2 2010 announced effective june 7 unlimited plan would replaced new customers 2 gb plan slightly lower cost existing customers would option keep unlimited plan plans activated ipad cancelled time ipad initially available purchase apple ’ online store retail locations since become available retailers including amazon walmart network operators ipad launched countries including australia canada france germany japan united kingdom may 28 online pre-orders countries began may 10 apple released ipad hong kong ireland mexico new zealand singapore july 23 2010 israel briefly prohibited importation ipad concerns wi-fi might interfere devices september 17 2010 ipad officially launched china ipad originally shipped iphone os 3.2 september 1 2010 announced ipad would get ios 4.2 november 2010 fulfill apple released ios 4.2.1 public november 22 comes several applications including safari mail photos video ipod itunes app store maps notes calendar contacts several improved versions applications developed iphone mac ipad syncs itunes mac windows pc apple ported iwork suite mac ipad sells pared-down versions pages numbers keynote apps app store although ipad designed replace mobile phone user use wired headset built-in speaker microphone place phone calls wi-fi 3g using voip application october 12 2011 ios 5 released various ios devices including first-generation ipad downloadable itunes update reported contain hundreds new features tweaks including twitter integration notification center imessage feature allows users send messages multimedia files users ios os x operating system apple computers icloud ios app apple-provided internet storage service allows users sync backup user data settings to/from devices also made available update june 11 2012 announced ios 6 would released first-generation ipad making ios 5.1.1 final operating system officially available device first-generation ipad features apple a4 soc comprises 1 ghz processor 256 mb ram powervr sgx535 gpu four physical switches ipad including home button near display returns user main menu three plastic physical switches sides wake/sleep volume up/down plus software-controlled switch whose function changed software updates originally switch locked screen current orientation ios 4.2 changed mute switch moving rotation lock function onscreen menu ios 4.3 update setting added allow user specify whether side switch used rotation lock mute unlike successors first-generation ipad cameras ipad touchscreen display 1,024 768 pixel liquid crystal display diagonal fingerprint- scratch-resistant glass result device screen dimensions resolution screen pixel density 132 ppi display responds sensors ambient light sensor adjust screen brightness 3-axis accelerometer sense ipad orientation switch portrait landscape modes unlike iphone ipod touch built-in applications work three orientations portrait landscape-left landscape-right ipad built-in applications support screen rotation four orientations including upside-down consequently device intrinsic native orientation relative position home button changes ipad equipped 16 gb 32 gb 64 gb solid-state flash memory program data storage furthermore device available two connectivity options wi-fi wi-fi cellular unlike successors wi-fi cellular variant first-generation ipad could support carriers utilized gsm/umts standards compatible cdma networks however like successors assisted gps services supported bluetooth also available models weight first-generation ipad varied dependent upon connectivity options chosen wi-fi variant weighs whereas variant wi-fi cellular weighs dimensions however identical across entire range variants measuring 9.56×7.47×0.50 243×190×13 mm apple offers several ipad accessories adapters proprietary 30-pin dock connector ipad port besides headphone jack dock holds ipad upright angle dock connector audio line-out port generation ipad requires corresponding dock dock included physical keyboard supported original ipad generations compatible bluetooth keyboards also work macs pcs ipad charged 10 w standalone power adapter also compatible ipods iphones media reaction announcement device device mixed media noted thousands people queued first day sale number countries many waited claiming worth walt mossberg wall street journal wrote software stupid meaning hardware features build less important ipad success software user interface first impressions largely positive mossberg also called price modest device capabilities praised ten-hour battery life others including pc advisor sydney morning herald wrote ipad would also compete proliferating netbooks use microsoft windows base model price 499 lower pre-release estimates wall street analysts apple competitors expecting much higher entry price point media also praised quantity applications well bookstore media applications contrast sources including bbc criticized ipad closed system mentioned ipad faces competition android-based tablets however time first-generation ipad launch yahoo news noted android tablet os known honeycomb open source fewer apps available ipad although later google released source code honeycomb independent criticized ipad readable bright light paper praised able store large quantities books uk release daily telegraph said ipad lack adobe flash support annoying ipad selected time magazine one 50 best inventions year 2010 popular science chose top gadget behind overall best new 2010 winner groasis waterboxx 300,000 ipads sold first day availability may 3 2010 apple sold million ipads half time took apple sell number original iphones passing one million mark continued selling rapidly reaching 3 million sales 80 days financial conference call october 18 2010 steve jobs announced apple sold ipads macs fiscal quarter total apple sold 15 million first-generation ipads prior launch ipad 2 – tablet pcs combined since ipad release reaching 75 tablet pc sales end 2010 cnet criticized ipad apparent lack wireless sync portable devices microsoft zune number years walt mossberg called pretty close laptop killer david pogue new york times wrote dual review one part technology-minded people part non-technology-minded people former section notes laptop offers features cheaper price ipad review latter audience however claims readers like concept device understand intended uses enjoy using device pc magazine tim gideon wrote winner undoubtedly driving force shaping emerging tablet landscape michael arrington techcrunch said ipad beats even optimistic expectations new category device also replace laptops many people pc world criticized ipad file sharing printing abilities arstechnica critically noted sharing files computer one least favorite parts ipad experience
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Operating systems
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advanced programmable interrupt controller computing intel advanced programmable interrupt controller apic family interrupt controllers name suggests apic advanced intel 8259 programmable interrupt controller pic particularly enabling construction multiprocessor systems one several architectural designs intended solve interrupt routing efficiency issues multiprocessor computer systems apic split architecture design local component lapic usually integrated processor optional i/o apic system bus first apic 82489dx discrete chip functioned local i/o apic 82489dx enabled construction symmetric multiprocessor smp systems intel 486 early pentium processors example reference two-way 486 smp system used three 82489dx chips two local apics one i/o apic starting p54c processor local apic functionality integrated intel processors silicon first dedicated i/o apic intel 82093aa intended piix3-based systems two components intel apic system local apic lapic i/o apic one lapic cpu system first implementation 82489dx lapic discrete circuit opposed thereafter implementation intel processors silicon typically one i/o apic peripheral bus system original system designs lapics i/o apics connected dedicated apic bus newer systems use system bus communication apic components apic whether discrete chip integrated cpu version register containing four-bit version number specific apic implementation example 82489dx apic version number 0 version 1 assigned first generation local apics integrated pentium 90 100 processors systems containing 8259 pic 8259 may connected lapic system bootstrap processor bsp one system i/o apics logically however 8259 connected given time first-generation intel apic chip 82489dx meant used intel 80486 early pentium processors actually external local i/o apic one circuit intel mp 1.4 specification refers discrete apic contrast integrated apic found pentium processors 82489dx 16 interrupt lines also quirk could lose isa interrupts multiprocessor 486 system cpu paired 82489dx additionally supplementary 82489dx used i/o apic 82489dx could emulate 8259a xt-pic also included physical chips backwards compatibility 82489dx packaged 132-pin pqfp local apics lapics manage external interrupts specific processor smp system addition able accept generate inter-processor interrupts ipis lapics lapics may support 224 usable interrupt vectors i/o apic vector numbers 0 31 0 255 reserved exception handling x86 processors intel processors starting p5 microarchitecture p54c built-in local apic however local apic disabled p5 processor re-enabled software limitation longer exists p6 processors later ones single-processor systems major advantage local apic pci cards longer need interrupts mapped isa interrupts use virtual pci irqs 15 resulting fewer conflicts better performance microsoft family operating systems windows xp first properly make use virtual irqs provided local apic partial support present windows 2000 windows 2000 spreading pci card interrupts virtual irq happens machine also i/o apic microsoft blamed windows 2000 implementation information received intel supposedly promising future systems would contain i/o apic well something retrospect happen microsoft document era even claimed without i/o apic system local apics useless situation windows 2000 revert using 8259 pic sudden widespread use local apic windows xp expose number bugs various bios implementations particular microsoft forced retain pci irq stacking behavior machine cardbus controller without i/o apic message signaled interrupts msi feature pci 2.2 later specifications used without local apic enabled use msi obviates need i/o apic additionally 224 interrupts supported msi mode irq sharing allowed another advantage local apic also provides high-resolution order one microsecond better timer used interval one-off mode apic timer initial acceptance woes microsoft document 2002 advocated adoption high precision event timer instead criticized lapic timer poor resolution stating clocks silicon sometimes buggy nevertheless apic timer used example windows 7 profiling enabled windows 8 circumstances windows 8 claimed exclusive rights timer also used programs like cpu-z microsoft windows apic timer shareable resource aperiodic interrupts offered apic timer used linux kernel 2.6.18 onwards implement tickless kernel feature legacy 8253 programmable interval timer longer used tickless kernels vmware document notes software reliable way determine frequency generally way determine local apic timer ’ frequency measure using pit cmos timer yields approximate result i/o apics contain redirection table used route interrupts receives peripheral buses one local apics first-generation dedicated i/o apic 82093aa support 24 interrupt lines packaged 64-pin pqfp 82093aa normally connected piix3 used integrated legacy 8259 pics according 2009 intel benchmark using linux i/o apic reduced interrupt latency factor almost three relative 8259 emulation xt-pic using msi reduced latency even factor nearly seven relative xt-pic baseline xapic introduced pentium 4 x2apic recent generation intel programmable interrupt controller introduced nehalem microarchitecture november 2008 major improvements x2apic address number supported cpus performance interface x2apic uses 32 bits address cpus allowing address 2 − 1 cpus using physical destination mode logical destination mode works differently introduces clusters using mode one address 2 − 16 processors x2apic architecture also provides backward compatibility modes original intel apic architecture introduced pentium/p6 xapic architecture introduced pentium 4 improved interface reduces number needed apic register access sending inter-processor interrupts ipis advantage qemu emulate x2apic older processors physically support going back conroe even amd opteron g-series processors neither natively support x2apic apicv intel brand name hardware virtualization support aimed reducing interrupt overhead guests apicv introduced ivy bridge-ep processor series sold xeon e5-26xx v2 launched late 2013 xeon e5-46xx v2 launched early 2014 amd announced similar technology called avic available family 15h models 6xh carrizo processors newer number known bugs implementations apic systems especially concern 8254 connected defective bioses may set interrupt routing properly provide incorrect acpi tables intel multiprocessor specification mps tables apic also cause system failure operating system support properly older operating systems i/o local apics often disabled possible anymore due prevalence symmetric multiprocessor multi-core systems bugs firmware operating systems rare occurrence amd cyrix proposed somewhat similar-in-purpose openpic architecture supporting 32 processors least declarative support ibm compaq around 1995 x86 motherboard released openpic however openpic failure x86 market amd licensed intel apic amd athlon later processors ibm however developed multiprocessor interrupt controller mpic based openpic register specifications mpic used powerpc based designs including ibm instance rs/6000 systems also apple late power mac g5s
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Computer architecture
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ibm websphere business events websphere business events ibm implementation event-processing engine event processing involves altering existing server software organization emit events small messages whenever notable event occurs event-processing software software monitor events look certain patterns interest useful prevention credit card fraud giving executives high-level view going company e.g share price drops extended period time detailed description see complex event processing software components following details websphere business events released june 2008 based upon acquisition aptsoft software
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Distributed computing architecture
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info-zip info-zip set open-source software handle zip archives circulation since 1989 consists 4 separately-installable packages zip unzip command-line utilities wiz maczip graphical user interfaces archiving programs microsoft windows classic mac os respectively info-zip zip unzip ported dozens computing platforms unzip web page describes unzip third portable program world surpassed hello world c-kermit possibly linux kernel zip unzip programs included linux unix distributions info-zip zip unzip addition info-zip releases parts info-zip including zlib used numerous file archivers programs many info-zip programmers also involved projects closely related deflate compression algorithm png image format zlib software library unzip package also includes three additional utilities zip package includes three additional utilities unzip 1.0 march 1989 released samuel m. smith written pascal c. pascal abandoned soon unzip 2.0 september 1989 released samuel m. smith included support unimploding method 6 introduced pkzip 1.01 george sipe created unix version unzip 2.0a december 1989 released carl mascott john cowan spring 1990 info-zip formed mailing list simtel20 released unzip 3.0 may 1990 became first public release info-zip group unzip 4.0 december 1990 adds support central directory within .zip archive unzip 5.0 august 1992 introduces support deflate method 8 compression method used pkzip 1.93a method 8 become de facto base standard zip archives 1994 1995 info-zip turned corner effectively became de facto zip program non-ms-dos systems huge number ports released year including numerous minicomputers mainframes practically every microcomputer ever developed unzip 5.41 april 2000 relicensed info-zip license unzip 5.50 february 2002 adds support deflate64 method 9 decompression unzip 6.0 adds support zip64 .zip archive bzip2 method 12 decompression support bzip2-style compression also zip 3.0f beta zip 1.9 august 1992 introduces support deflate method 8 compression method method 8 become de facto base standard zip archives zip 2.3 december 1999 first info-zip archiver tool new bsd-like info-zip license zip 3.0 2008-07-07 supports zip64 .zip archive 65536 files per archive multi-part archive bzip2 compression unicode utf-8 filename partial comment unix 32-bit uids/gids wiz 4.0 november 1997 released info-zip wiz 5.01 april 2000 relicensed info-zip license maczip 1.05 july 2000 released info-zip license maczip 1.06 released february 2001 written dirk hasse
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Computer file systems
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bootstrap protocol bootstrap protocol bootp computer networking protocol used internet protocol networks automatically assign ip address network devices configuration server bootp originally defined rfc 951 computer connected network powered boots operating system system software broadcasts bootp messages onto network request ip address assignment bootp configuration server assigns ip address based request pool addresses configured administrator bootp implemented using user datagram protocol udp transport protocol port number 67 used dhcp server receive client requests port number 68 used client receive dhcp server responses bootp operates ipv4 networks historically bootp also used unix-like diskless workstations obtain network location boot image addition ip address assignment enterprises used roll pre-configured client e.g. windows installation newly installed pcs originally requiring use boot floppy disk establish initial network connection manufacturers network cards later embedded protocol bios interface cards well system boards on-board network adapters thus allowing direct network booting parts bootp effectively superseded dynamic host configuration protocol dhcp adds feature leases parts bootp used provide service dhcp protocol dhcp servers also provide legacy bootp functionality bootp first defined september 1985 rfc 951 replacement reverse address resolution protocol rarp published rfc 903 june 1984 primary motivation replacing rarp bootp rarp link layer protocol made implementation difficult many server platforms required server present individual ip subnet bootp introduced innovation relay agents forwarded bootp packets local network using standard ip routing one central bootp server could serve hosts many subnets case 1 client server network case 2 client server different networks
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Internet protocols
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david venable david dave venable born january 11 1978 little rock arkansas former intelligence officer united states national security agency current cyber security professional businessman author speaker topics cyber security cyberwarfare international security also developed security-related internet protocols dave venable grew little rock arkansas arkansas later attended university arkansas majoring mathematics college venable joined united states air force studied korean defense language institute monterey california department defense educational research institution provides linguistic cultural instruction dod federal agencies venable also pursued graduate education mathematics university texas international relations harvard university 2005 venable served several intelligence roles national security agency including computer network exploitation cyberwarfare information operations digital network intelligence support global anti-terrorism operations also taught subjects serving adjunct faculty national cryptologic school school within national security agency provides training members united states intelligence community leaving federal service venable founded served ceo vanda security dallas-based security consultancy ultimately became security professional services practice masergy communications venable currently serves vice president cyber security venable regularly speaks industry government conferences including black hat briefings warsaw security forum serves cyber security expert think tanks policy research institutes serves colony texas technology board venable frequently contributes appears forbes bbc harvard business review bloomberg businessweek informationweek idg connect media outlets matters pertaining cyber security cyberwarfare international security
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Computer security
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cisco pix cisco pix private internet exchange popular ip firewall network address translation nat appliance one first products market segment 2005 cisco introduced newer cisco adaptive security appliance cisco asa inherited many pix features 2008 announced pix end-of-sale pix technology sold blade firewall services module fwsm cisco catalyst 6500 switch series 7600 router series reached end support status september 26 2007 pix originally conceived early 1994 john mayes redwood city california designed coded brantley coile athens georgia pix name derived creators aim creating functional equivalent ip pbx solve then-emerging registered ip address shortage time nat investigated viable approach wanted conceal block blocks ip addresses behind single multiple registered ip addresses much pbxs internal phone extensions began rfc 1597 rfc 1631 discussed now-familiar rfc 1918 yet submitted design testing carried 1994 john mayes brantley coile johnson wu network translation inc. brantley coile sole software developer beta testing pix serial number 000000 completed first customer acceptance december 21 1994 kla instruments san jose california pix quickly became one leading enterprise firewall products awarded data communications magazine hot product year award january 1995 shortly cisco acquired network translation november 1995 mayes coile hired two longtime associates richard chip howes pete tenereillo shortly acquisition 2 longtime associates jim jordan tom bohannon together continued development finesse os original version cisco pix firewall known pix classic time pix shared code another cisco product localdirector january 28 2008 cisco announced end-of-sale end-of-life dates cisco pix security appliances software accessories licenses last day purchasing cisco pix security appliance platforms bundles july 28 2008 last day purchase accessories licenses january 27 2009 cisco ended support cisco pix security appliance customers july 29 2013 may 2005 cisco introduced asa combines functionality pix vpn 3000 series ips product lines asa series devices run pix code 7.0 later pix os release 7.x pix asa use software images beginning pix os version 8.x operating system code diverges asa using linux kernel pix continuing use traditional finesse/pix os combination pix runs custom-written proprietary operating system originally called finese fast internet service executive software known simply pix os though classified network-layer firewall stateful inspection technically pix would precisely called layer 4 transport layer firewall access restricted network layer routing socket-based connections port ip address port communications occur layer 4 default allows internal connections outbound traffic allows inbound traffic response valid request allowed access control list acl conduit administrators configure pix perform many functions including network address translation nat port address translation pat well serving virtual private network vpn endpoint appliance pix became first commercially available firewall product introduce protocol specific filtering introduction fixup command pix fixup capability allows firewall apply additional security policies connections identified using specific protocols protocols specific fixup behaviors developed include dns smtp dns fixup originally implemented simple effective security policy allowed one dns response dns server internet known outside interface dns request client protected known inside interface inspect superseded fixup later versions pix os cisco pix also one first commercially available security appliances incorporate ipsec vpn gateway functionality administrators manage pix via command line interface cli via graphical user interface gui access cli serial console telnet ssh gui administration originated version 4.1 several incarnations cisco acquired pix network translation cli originally align cisco ios syntax starting version 7.0 configuration became much ios-like original nti pix pix classic cases sourced oem provider appro flash cards early encryption acceleration cards pix-pl pix-pl2 sourced productivity enhancement products pep later models cases cisco oem manufacturers pix constructed using intel-based/intel-compatible motherboards pix 501 used amd 5x86 processor standalone models used intel 80486 pentium iii processors pix boots proprietary isa flash memory daughtercard case nti pix pix classic 10000 510 520 535 boots integrated flash memory case pix 501 506/506e 515/515e 525 ws-svc-fwm-1-k9 latter part code pix technology implemented fire wall services module catalyst 6500 7600 router adaptive security appliance network firewall made cisco introduced 2005 replace cisco pix line along stateful firewall functionality another focus asa virtual private network vpn functionality also features intrusion prevention voice ip asa 5500 series followed 5500-x series 5500-x series focuses virtualization hardware acceleration security modules 2005 cisco released 5510 5520 5540 models asa continues using pix codebase asa os software transitioned major version 7.x 8.x moved finesse/pix os operating system platform linux operating system platform also integrates features cisco ips 4200 intrusion prevention system cisco vpn 3000 concentrator asa continues pix lineage intel 80x86 hardware cisco pix vpn product hacked nsa-tied group equation group somewhere 2016 equation group developed tool code-named benigncertain reveals pre-shared password attacker cve-2016-6415 equation group later hacked another group called shadow brokers published exploit publicly among others according ars technica nsa likely used vulnerability wiretap vpn-connections decade citing snowden leaks cisco asa-brand also hacked equation group vulnerability requires ssh snmp accessible attacker codename given exploit nsa extrabacon bug exploit cve-2016-6366 also leaked shadowbrokers batch exploits backdoors according ars technica exploit easily made work modern versions cisco asa leaked exploit handle 29th january 2018 security problem cisco asa-brand disclosed cedric halbronn ncc group use free-bug secure sockets layer ssl vpn functionality cisco adaptive security appliance asa software could allow unauthenticated remote attacker cause reload affected system remotely execute code bug listed cve-2018-0101
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Computer security
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nokia n900 nokia n900 smartphone made nokia supersedes nokia n810 default operating system maemo 5 linux-based os originally developed nokia 770 internet tablet first nokia device based upon texas instruments omap3 microprocessor arm cortex-a8 core unlike three nokia internet tablets preceding nokia n900 first maemo device include phone functionality quad-band gsm 3g umts/hsdpa n900 functions mobile internet device includes e-mail web browsing access online services 5-megapixel digital camera still video photography portable media player music video calculator games console word processor sms well mobile telephony using either mobile network voip via internet mobile wi-fi maemo provides x-terminal interface interacting core operating system launched nokia world 2 september 2009 released 11 november 2009 united states 9 european countries n900 launched alongside maemo 5 giving device overall touch-friendly interface predecessors customizable home screen mixes application icons shortcuts widgets maemo 5 supports adobe flash player 9.4 includes many applications designed specifically mobile platform new touch-friendly media player nokia n900 announced 17 september 2008 keynote presentation dr. ari jaaksi nokia new supported features announced maemo 5 cellular connectivity 3g/hspa ti omap3 processor high definition camera support news backward compatibility older internet tablets time frame established release pre-alpha maemo 5 software development kit december 2008 targeted exclusively omap3 architecture revamped user interface included support hardware graphics acceleration functionalities found internet tablets time cellular data connectivity high definition camera support first photo specifications n900 codenamed rover developed came may 2009 release fcc approval documents august 2009 confirmed device provided second codename rx-51 nokia n900 officially announced 2 september 2009 nokia world 2009 germany nokia says step 4 5 line maemo devices started 2005 nokia 770 device initially available selected markets starting november 2009 4 december uk retail price €599 finland germany italy netherlands spain €649 france 2499 zł poland 5995 kr sweden £499 united kingdom prices including vat excluding subsidies retail price launch us 649 united states excluding sales taxes subsidies available canada independent retailers around c 800 march 2010 nokia site australia lists n900 homepage hinting launch time near future black color available launch initially availability extremely limited leading delays statement nokia higher pre-order demand expected nokia n900 launched hong kong 29 may 2010 added features facilitate character handwriting input price launch 4998 hkd already released australia via optus nokia n900 powered omap 3430 arm cortex-a8 system-on-a-chip made texas instruments based 65 nanometer cmos process omap 3430 composed three microprocessors cortex a8 running 600 mhz 1.15 ghz correct overclocking used run os applications powervr sgx530 gpu made imagination technologies supports opengl es 2.0 capable 14 mpolys/s tms320c64x digital signal processors running 430 mhz used run image processing camera audio processing telephony data transmission tms320 c64x main purpose offload cortex a8 process audio video signal moreover omap 3430 n900 devices successfully over-clocked 1150 mhz using modified kernel editing kernel power configuration file system 256 mb dedicated high performance ram mobile ddr paired access 768 mb swap space managed os provides total 1 gb virtual memory nokia n900 resistive touchscreen resolution 800 × 480 pixel wvga 267 ppi according nokia xorg.log capable displaying 65k colours 565 rgb nokia n900 camera capability 2592x1944 pixels carl zeiss optics autofocus dual led flash video light geo-tagging lcd transflective permit usability wide range luminosity daylight dark haptic feedback provided touchscreen input applying small vibration sound user choose whether feature enabled stylus provided allow precise touch input access smaller user interface elements 3-axis accelerometer allows orientation screen change portrait landscape mode certain applications used user input games applications dashboard desktop active rotating device landscape portrait mode activates phone application feature also disabled user discretion update pr1.2 became possible view web pages portrait mode developers may add support portrait mode applications desired proximity sensor deactivates display touchscreen device brought near face call slide-out 4-row keyboard d-pad nokia n810 replaced nokia n900 slide-out 3-row backlit keyboard arrow keys previous internet tablets on-screen keyboard also available addition english qwerty layout slide keyboard available variants italian french german russian czech nordic finnish swedish spanish nokia n900 ambient light sensor adjusts display brightness activates backlit keyboard os comes word prediction software configured user preferences auto capitalization word completion auto spacing words device autonomous gps optional a-gps functionality comes pre-loaded ovi maps application ovi maps provides typical mapping features alternate views 3d landmarks satellite hybrid maps address/places interest searching route planning although turn-by-turn navigation yet 5-megapixel back camera autofocus feature dual led flash 4:3 16:9 aspect ratio options 3× digital zoom focal length camera 5.2 mm aperture f/2.8 focus range 10 cm infinity capable video recording 848 × 480 pixels 25 fps lens use protected sliding hatch opening hatch launches camera application although 0.3-megapixel front camera capable video recording 640 × 480 pixels pre-production units could used video calls ip using google talk retail version delivered without software enabling video calling video chatting update pr1.2 ota over-the-air skype video calling added enabling fascia camera software updates phone becomes capable play/record/stream 720p video holding device facing screen top left right rocking buttons function volume up/down zoom in/out depending context power on/off camera button pressing power button brings menu change profile activate offline mode a.k.a airplane flight mode turns emitted signals lock device either secure key code simple lock option end current task nokia n900 fewer hardware buttons makes use touchscreen display on-screen buttons example accept reject end call n900 microphone stereo speakers located side device 3.5 mm four-contact trrs connector simultaneously provides stereo audio output either microphone input video output pal ntsc tv possible using nokia video connectivity cable included upon purchase standard trrs 3x rca cable high-speed usb 2.0 usb micro-b connector provided data synchronization mass storage mode client battery charging micro-usb connector prone failure nokia n900 unlike previous versions nokia internet tablet n't enabled support usb on-the-go ability act usb host default order meet deadlines production usb certification ongoing community effort add support subsequently currently software beta stage requiring non-standard usb cable usb a-a adapter software development repository built-in bluetooth v2.1 supports wireless earpieces headphones hsp profile nokia n900 supports hardware capable stereo audio output a2dp profile built-in car hands-free kits also supported hfp profile file transfer supported ftp along opp profile sending/receiving objects possible remote control device avrcp profile dun profile permits access internet laptop dialing mobile phone wirelessly tethering hid profile provides support devices bluetooth keyboards pan profile networking using bluetooth unsupported enabled bluetooth set also functions fm receiver allowing one listen fm radio n900 also 88.1–107.9 mhz fm transmitter example play music separate radio note fm transmitter frequency range extended 76.0–107.9 mhz community supported modifications operating system furthermore nokia n900 wi-fi b/g connectivity support wep wpa wpa2 aes/tkip security protocols nokia n900 synchronize microsoft outlook activesync various e-mail calendar clients syncml bluetooth micro-usb contact information also exchanged via vcard file format supported commonly e-mail programs including evolution microsoft outlook device also features infrared port compatible irda used turn nokia n900 remote controller using third-party software battery life shipped bl-5j 1320mah battery n900 seems deficient able make full working day internet connection call usage press release nokia stated aiming one day full usage always online 2-4 days tcp/ip connected active online usage 1+ day early reports users range 12 hours wi-fi web browsing video gps 2 days online used continuously value appears highly dependent user choice background software active desktop widgets im email polling well mobile network signal quality especially 3g cases software bugs nokia reported talk times around 9 hours gsm 5 hours 3g battery life extended significantly switching gps/a-gps wi-fi bluetooth replacing 3g 2g gprs previous internet tablets used larger batteries 1500 mah compared n900 1320 mah based less efficient microprocessor typical battery time nokia n810 around 7 hours continuous full usage display wi-fi principle n900 figures expected much higher third party extended batteries 2400 mah capacity available n900 also community supported modifications performed 3rd party n900 compatible batteries usually involving putting two said batteries parallel increase effective battery capacity nokia n900 3000 mah sim card located battery accessed removing back panel nokia n900 microsd hc card socket also located back cover battery tool necessary remove back panel nokia n900 32 gb emmc 256 mb nand non-removable storage additional storage available via hot swappable microsdhc card socket claimed support 200 gb additional storage however sdhc specification supports cards 32 gb size difficulty reported use 64+ gb sdxc cards sandisk claims sdxc cards compatible n900 hot swapping achieved via software-supported magnetic sensor detects removal back cover partition residing microsdhc card unmounted back cover removed microsdhc card formatted supported file system ext2 ext3 fat16 fat32 32 gb emmc split 3 partitions 256 mb nand formatted ubifs contains bootloader kernel image root directory 100 mb free space programs larger 500 kb including dependencies stored /opt symlinked /home/opt therefore located 2 gb ext3 partition vfat partition also available storage needs used carefully unmounted exported usb cable connected device maemo 5 also known fremantle default operating system nokia n900 maemo 5 nokia adaptation linux desktop environment pocket-sized device ui fully customizable user able move widgets around add/remove widgets change background add shortcuts applications n900 comes preloaded variety applications 1500 additional applications overwhelming majority free download use created 3rd party developers custom kernels also available via app manager users need devices maemo uses upstart reduce boot time application called easy debian installs debian lxde image internal memory enabling applications iceweasel firefox browser openoffice.org suite run within maemo applications synaptic package manager included debian installation gimp run within lxde interface software also added debian using maemo chroot utility using synaptic apt-get command line stellarium zim desktop wiki accessed either via lxde desktop icons program manager shortcuts desktop nokia n900 sim application toolkit available also known operator menu possible use services require result support sim interact directly outside world initiate commands independently handset network making n900 vulnerable installation malicious sim java applications via text messages issues various value-added services resulting availability sim application toolkit include following nokia often offers new n8 e7 devices warranty replacements n900s although warranty terms consumer rights legislation differ across jurisdictions users reported success refusing pressing n900 least eu india recently august 2011 owners confident getting n900 warranty replacement often attempt repair devices sell nokia-provided replacement buy n900 instead n900 proximity sensor designed lock touch screen phone user ear prevent accidental operation locks screen unintentionally bright light usually outdoors call placed received nokia acknowledged hardware issue addressed unlock screen phone call tactile unlock switch right side device used however keep touch screen active accidental operation phone keys call may occur device used handset issue blamed application screen protectors however n900 users without screen protectors also experiencing problem n900 microusb charger port fragile people successfully fixed problem either epoxy glue resoldering usb port onto circuit board chips n900 gsm module might badly soldered circuit board resulting multiple n900 devices reported troubled inability sim card detected issue fixable putting something gsm-related chips shielding though proper fix would reballing announced may 2010 nokia n900 last mobile communication device running maemo 5 operating system replaced meego nokia continue support n900 updates necessary transition succeeding meego operating system possible mainly interest developers rather consumers officially supported nokia interest within user community working backporting meego developments maemo n900 places interesting device people within wider open source community consumers download meego operating system available officially supported nokia nokia used say meego going succeed maemo new devices however 11 february 2011 nokia announced primarily concentrating alliance microsoft meego development stopped one meego device become available 2011 3 march 2011 jukka eklund product manager meego os nokia announced meego-dev mailing list meego 1.2 developer edition n900 developed dedicated nokia team led mika leppinen target particular edition usable primary phone device developer/hacker person regular end users september 2011 announcement intel linux foundation abandoning meego favor tizen prompted developer community begin seriously doubt future meego n900 meego developer edition rename meego community edition evolved nemo based mer currently october 2012 actively developed nitdroid project ports android devices alternate operating system also available n900 however little progress made achieving voice calling nitdroid n900 main developer goes online handle e-yes moved developing devices nokia n9 community-based project aiming provide hardware upgrade n900 called neo900 began late 2013 collaboration openmoko maemo communities hardware upgrade quadruple device ram provide processor nearly twice fast one original n900 integrate additional sensors gyroscope compass likely modern lte modem also included
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Operating systems
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telechips telechips fabless company headquartered seoul founded 1999 regional offices japan china singapore designs integrated circuits company sells system chip products used automotive entertainment systems consumer electronics based arm architecture support android windows embedded compact nucleus rtos linux telechips also sells development kits
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Computer architecture
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servedby net servedby net llc cloud computing provider specializing infrastructure service company provides infrastructure efforts virtual servers storage server backup company current slogan serving clouds seattle servedby net founded seattle washington joshua breeds breeds developed interest cloud technology sector age 10 developed first web hosting company years later breeds founded servedby net llc 2011 working biochemistry degree university washington 2014 organization technology partner microsoft vmware parallels suse f5 networks servedby net offers cloud iaas infrastructure service well hosted services managed cloud services domain name registration
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Distributed computing architecture
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windows internal database windows internal database codenamed wyukon sometimes referred sql server embedded edition variant sql server express 2005–2014 included windows server 2008 sql 2005 windows server 2008 r2 sql 2005 windows server 2012 sql 2012 windows server 2012 r2 sql 2012 windows server 2016 sql 2014 included free microsoft products released 2007 require sql server database backend windows sharepoint services 3.0 windows server update services 3.0 include windows internal database used alternative using retail edition sql server wid 32-bit application even component windows server 2008 64-bit installs path windows server 2012 later 64-bit application installed windows internal database available standalone product use end-user applications microsoft provides sql server express microsoft sql server purpose additionally designed accessible windows services running machine several components windows server 2008 2012 use windows internal database data storage active directory rights management services windows system resource manager uddi services active directory federation services 2.0 ipam windows sharepoint services windows server 2003 sharepoint windows server update services install windows internal database use default data store retail sql server database instance provided knowledge base article published microsoft states windows internal database identify removable component provides instructions may uninstalled calling windows installer directly sql server management studio express used connect instance windows internal database using codice_1 2003–2008 codice_2 2012 instance name work locally remote connections enabled edition sql server also note windows authentication used opposed sql server authentication administrators seem best results authenticating successfully logged using administrative account created windows installed
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Operating systems
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thinkpad thinkpad line business-oriented laptop computers tablets designed developed marketed sold lenovo formerly ibm thinkpads known minimalist black boxy design initially modeled 1990 industrial designer richard sapper based concept traditional japanese bento lunchbox revealing nature opened according later interviews sapper also characterized simple thinkpad form elementary simple black cigar box similar proportions offers 'surprise opened thinkpad line first developed ibm yamato facility japan led arimasa naitoh dubbed father thinkpad first thinkpads released october 1992 considered innovative became large success ibm decade thinkpads especially popular businesses older models revered technology enthusiasts collectors power users due durable design relatively high resale value abundance aftermarket replacement parts thinkpads received somewhat cult following small loyal fanbase throughout years aftermarket parts developed models custom motherboards current processors created x60 x200 thinkpad laptops used outer space 2003 laptops certified use international space station name thinkpad product ibm corporate history culture thomas j. watson sr. first introduced think ibm slogan 1920s every minicomputer mainframe ibm installed almost leased – sold blue plastic sign placed atop operator console think command aluminum plate decades ibm distributed small notepads word think emblazoned brown leatherette cover customers employees name thinkpad suggested ibm employee denny wainwright think notepad pocket name opposed ibm corporate naming committee names ibm computers numeric time thinkpad kept due praise journalists public thinkpad ibm answer toshiba compaq notebook market well apple dec task making notebook given yamato facility japan led arimasa naitoh japanese man joined ibm 1970s dubbed father thinkpad ibm pushing thinkpad 1992 launch keep harvard business school happy april 1992 ibm announced first thinkpad tablet computer news conference first thinkpad tablet penpoint-based device formally known ibm 2521 thinkpad positioned developer release thinkpad tablet became available purchase general public october year addition giving innovative name ibm marketed thinkpad imaginative activities early customer pilot programs numerous pre-launch announcements extensive loaner program designed showcase product strengths weaknesses ibm even worked archaeologists excavating ancient egyptian city leontopolis field test thinkpad device loaned dig team summer resulting report documented thinkpad excellent performance difficult conditions report said thinkpad impressive machine rugged enough used without special care worst conditions egypt offer first thinkpad model announced april 1992 700 renamed 700t release three newer models 300 new 700 700c october 1992 bright red trackpoint kind pointing stick embedded keyboard enabled notebook used without external pointing device first thinkpads successful collecting 300 awards design quality thinkpad 755c laptop computers used payload general support computers aboard space shuttle 1990s thinkpad 760ed also tested part shuttle–mir program period 760ed computer used without modification model used space program contained intel 133 mega hertz pentium processor 48 megabytes ram four speed cd-rom power supply unit 1.44 megabyte floppy disk drive two 1.2 gigabyte hard drives accessories use space laptops subject radiation could cause errors 760ed noted improvement area 755c traditionally black thinkpads commonly featured magnesium carbon fiber reinforced plastic titanium composite cases thinkpad introduced innovations including trackpoint pointing device thinklight led keyboard light top lcd screen active protection system accelerometer sensor detects thinkpad falling shuts hard disk drive prevent damage roll cage design minimize motherboard flex stainless steel hinges biometric fingerprint reader client security solution improves security using built-in trusted platform module tpm facilitates deployment corporate environment thinkvantage technologies suite computer management applications drain holes help reduce damage keyboard components accidental spillage original design concept thinkpad created 1990 italy-based designer richard sapper corporate design consultant ibm since 2005 lenovo sapper noted design classic products tizio lamp artemide office chair knoll kitchenwares alessi ballpoint lamy design based concept traditional japanese bento lunchbox revealing nature opened according later interviews sapper also characterized simple thinkpad form elementary simple black cigar box similar proportions offers 'surprise opened computers also known iconic red trackpoint variation joystick middle keyboard first thinkpad notebook 700c announced 1992 first new product emerge ibm differentiated product personality strategy resulting collaboration sapper tom hardy head corporate ibm design program development 700c also involved close working relationship sapper kazuhiko yamazaki lead notebook designer ibm yamato design center japan liaison sapper yamato engineering 1990–1992 pre-internet collaboration italy japan facilitated special sony digital communications system transmitted high-res images telephone lines system established several key global design centers hardy ibm designers could visually communicate effectively interact directly sapper advice projects innovative design management leadership thinkpad development hardy named innovator year 1992 pc magazine since 1992 thinkpad design regularly updated developed refined years sapper respective teams ibm later lenovo included yamazaki tom takahashi sam lucente since 1995 david hill vice president user experience design leads manages design/user experience thinkpad hill approach maintaining evolution sapper original thinkpad design analogous porsche manages evolution classic 911 fold-out butterfly keyboard appeared thinkpad 701 series designed sapper collaboration sam lucente john karidis widely considered design masterpiece display museum modern art new york city thinkpad 760 series also included unusual keyboard design keyboard elevated two arms riding small rails side screen tilting keyboard achieve ergonomic design although almost models feature trackpoint models touchpad left right buttons possibly making mouse clicks less ergonomic touchpads x220 double regular mouse buttons also case newer models december 2013 cause problems accidental clicking much pressure exerted mouse movements occasion 20th anniversary thinkpad introduction david hill authored designed commemorative book thinkpad design titled thinkpad design spirit essence book revealed event held moma thinkpads especially popular businesses older models revered technology enthusiasts collectors power users due durable design relatively high resale value abundance aftermarket replacement parts thinkpads received somewhat cult following small loyal fanbase throughout years laptop magazine 2006 called thinkpad highest-quality laptop computer keyboard available ranked first reliability support pc magazine 2007 survey lenovo thinkpad pc magazine 2006 reader choice pc based laptops ranked number 1 support pc based laptops thinkpad series first product receive pc world hall fame award enderle group rob enderle said constant thing thinkpad brand stands quality build best keyboard business thinkpad x tablet-series pc magazine editor choice tablet pcs thinkpad x60s ranked number one ultraportable laptops pc world lasted 8 hours 21 minutes single charge 8-cell battery lenovo thinkpad x60s series pc world top 100 products 2006 2005 pc world reliability service survey ranked thinkpad products ahead brands reliability 2004 survey ranked second behind emachines lenovo named environment-friendly company electronics industry greenpeace 2007 since dropped place 14 17 october 2010 lenovo thinkpad t60p received editor choice award mobile graphic workstation pc magazine lenovo thinkpad x60 pc magazine editor choice among ultra-portable laptops lenovo thinkpad t400-series pc world top 100 products 2009 thinkpad laptops 2003 laptops certified use international space station 2017 currently operate linux windows xp windows vista software nasa purchased 500 thinkpad 750 laptops flight qualification software development crew training astronaut senator john glenn used thinkpad laptops spaceflight mission sts-95 1998 thinkpad models used shuttle missions include least three thinkpad 750c left spektr module mir module depressurized laptops used aboard space shuttle international space station feature safety operational improvements weightless environment must operate modifications include velcro tape attach surfaces upgrades cpu video card cooling fans accommodate microgravity hotter air n't rise lower density cabin air adapter station 28 volt dc power thinkpad 750 flew aboard space shuttle endeavour mission repair hubble space telescope 2 december 1993 thinkpad 750c task run nasa test program determined radiation inherent space environment causes memory anomalies 750c generates unexpected problems 755c also used 760ed tested well part shuttle–mir test thinkpads used conjunction joystick portable in-flight landing operations trainer pilot throughout 2006 thinkpad a31p used service module central post international space station seven thinkpad a31p laptops service orbit aboard international space station 2010 space station equipped 68 thinkpad a31 computers along 32 new lenovo thinkpad t61p laptops plus dedicated ip phone also limited video phone capabilities work incorporating laptops station lan continued june 2011 laptops aboard iss connected station lan via wi-fi connected ground 3 mbit/s 10 mbit/s comparable home dsl connection speeds 2005 chinese technology company lenovo purchased ibm personal computer business thinkpad flagship brand along speaking purchase ibm personal computer division liu chuanzhi said benefited three ways ibm acquisition got thinkpad brand ibm advanced pc manufacturing technology company international resources global sales channels operation teams three elements shored sales revenue past several years although lenovo acquired right use ibm brand name five years acquisition ibm personal computer business lenovo used three years majority thinkpad computers since 2005 acquisition brand lenovo made china addition chinese manufacturing facilities lenovo employs 300 people combined manufacturing distribution center near american headquarters morrisville north carolina device made facility packed box sports red-white-and-blue sticker proclaiming whitsett north carolina 2012 lenovo partially moved production thinkpad line computers japan thinkpads produced nec yonezawa yamagata akaemi watanabe president lenovo japan said japanese glad see return domestic production goal realize full-scale production improve image make products acceptable japanese customers 2014 although sales rose 5.6 percent previous year lenovo lost position top commercial notebook maker however company celebrated milestone 2015 shipment 100 millionth unit thinkpad line lenovo laptops x230 w530 t430 block third-party batteries lenovo calls feature battery safeguard first introduced models may 2012 laptops feature scan security chips thinkpad-branded batteries contain affected thinkpads flash message stating genuine lenovo battery attached third-party batteries used thinkpad yoga ultrabook-class convertible device functions laptop tablet computer yoga gets name consumer-oriented ideapad yoga line computers form factor thinkpad yoga backlit keyboard flattens flipped tablet mode accomplished platform surrounding keys rises level keyboard buttons locking mechanism prevents key presses feet pop prevent keyboard directly resting flat surfaces lenovo implemented design response complaints earlier yoga 13 11 models awkward use tablet mode reinforced hinge required implement design convertible form factor thinkpad yoga retains standard thinkpad features black magnesium-reinforced chassis island keyboard red trackpoint large buttonless trackpad released august 2011 thinkpad tablet first lenovo line business-oriented tablets thinkpad brand tablet described gadget mix premium business tablet since tablet primarily business-oriented includes features security anti-theft software ability remotely disable tablet sd card encryption layered data encryption cisco virtual private network vpn additionally thinkpad tablet able run software ibm lotus notes traveler stylus could used write notes tablet also included software convert handwritten content text another feature tablet drag-and-drop utility designed take advantage tablet touch capabilities feature could used transfer data usb devices internal storage sd card slashgear summarized thinkpad tablet saying stylus styling add distinctive slate n't merely attempt ape apple ipad order celebrate 20th anniversary thinkpad lenovo held large party new york announced several products including tablet 2 lenovo says thinkpad tablet 2 available 28 october 2012 windows 8 released thinkpad tablet 2 runs windows 8 professional operating system able run desktop software compatible version windows tablet 2 based clover trail version intel atom processor customized tablets tablet 2 2 gigabytes ram 64gb ssd tablet 2 10.1-inch ips display 16:9 aspect ratio resolution preview cnet wrote windows 8 looked readable functional metro standard windows-based interfaces mini-hdmi port included video output 8-megapixel rear camera 2-megapixel front camera included along noise-canceling microphone order facilitate video conferencing announced released january 2014 thinkpad 8 based intel bay trail atom z3770 processor 2 gb ram 128 gb built-in storage thinkpad 8 8.3-inch ips display 16:10 aspect ratio resolution pixels features include aluminum chassis micro-hdmi port 8-megapixel back camera flash optional 4g connectivity runs windows 8 operating system announced may 2014 lenovo thinkpad 10 successor thinkpad tablet 2 scheduled launch summer 2014 along accessories docking station external detachable magnetic keyboards used windows 8.1 pro operating system available 64 128gb variants 1.6ghz quad-core intel atom baytrail processor 2gb 4gb ram optionally supported 3g 4g lte display resolution announced paired stylus pen thinkpad x1 tablet fanless tablet powered core cpus available 4 8 16gb lpddr3 ram sata pcie nvme ssds 1tb ips screen supports touch pen input thinkpad 11e budget laptop computer schools students 11-inch screen without trackpoint 11e yoga convertible version 11e e series low-cost thinkpad line designed small business mass-market requirements currently contains 14 15 sub-lines e series line laptops replaced lenovo edge series somewhere countries currently may 2019 offered thinkpad edge/e series names l series replaced former r series positioned mid-range thinkpad offering mainstream intel core i3/i5/i7 cpus l series 3 sub-lines long-running 14 15.6 launched line two models l412 l512 2010 2018 also 13 l380 available replaces thinkpad 13 main difference e series l series basic mil-std-810 certification l series thinkpads series historically high-end features magnesium alloy rollcages high-density ips screens known flexview discontinued t60 series 7-row keyboards screen latches lenovo ultrabay thinklight models included 14.1-inch 15.4-inch displays available 4:3 16:10 aspect ratios since 2012 entire thinkpad line given complete overhaul modifications removal separate buttons use trackpoint reintroduced 2015 removal separate audio control buttons removal screen latch removal led indicator lights new ultra-portable models t430u t431s non-replaceable batteries newer models combination built-in replaceable battery enabling user switch replaceable without putting computer hibernation also non-widescreen displays longer available 16:9 aspect ratio remaining choice x series main high-end ultraportable thinkpad line offering lightweight highly portable laptop moderate performance current sub-lines x series includes daughter line includes x1 tablet confused 2005-2013 x series tablets mainstream current workhorse models x390 x390 yoga 13 successors classic discountinued 12 line lenovo x series thinkpads premium 14 /15 thin-and-light line 13.3 thinkpad models x300/x301 ultrabay cd-rom removable battery replaced modern premium x1-series ultrabook line x1 carbon x1 yoga x1 extreme sub-series discountinued mainstream lines 12 x200 x201 x220 models could ordered high-end thinkpad features like trackpoint thinklight 7-row keyboard docking port hot-swappable hdd solid magnesium case optional slice battery discontinued 12.5 x220 x230 still featured roll cage thinklight optional premium ips display first ips display non-tablet thinkpad since t60p 7-row keyboard offered x220 however lacked lid latch mechanism present previous x200 x201 versions discontinued slim 12 line contained x200s x201s low power cpus high resolution displays x230s low power cpus 12.5 x series thinkpads x240 later simplified design last 12 x280 model trackpoint feature partially magnesium case simplified docking port obsolete low-cost 11.6 netbook line x100e x120e plastic lacking latch thinklight using variant island keyboard known chiclet keyboard found edge series x100e also offered red addition blue white countries like high-end netbooks whereas x200 series like full ultraportables featuring intel core previously core 2 celeron series cpus rather amd netbook cpus x series tablet suffixes outdated variant 12 x series models low voltage cpus flip-screen tablet resistive touchscreen include traditional thinkpad features noted using higher quality affs-type screen better viewing angles compared screens used thinkpads p series line laptops replaced lenovo w series p series excluding models suffix designed engineers architects animators etc comes variety high-end options p series models included fingerprint readers first generation comes variety high-end options intel xeon processors 4k screens ddr4 ram 64gb 1080p screens intel core series cpus pcie ssds come standard p series uses cooling system known flex features two fans connected heat pipe located near cpu gpu three-button touchpad included color calibrator dropped nvidia pascal gpus new dock stations side connection port hardware update optional oled screen p1 gen2 thinkpad stack line products includes accessories designed portability interoperability line includes external hard drives wireless router power bank bluetooth 4.0 speaker stack device includes rubber feet magnets pogo-pin power connections allow use single cable combined weight stack devices slightly less two pounds stack series announced january 2015 international ces stack series accessories expanded 2016 international ces include 720p resolution projector 150 lumens brightness wireless charging station stack blocky black rectangular look thinkpad logo shares common design language thinkpad laptop computers dock stations finder thinkpad usb 3.0 secure hard drive thinkpad keyboards thinkpad stands japan-only thinkpad 235 type 2607 progeny ibm/ricoh rios project also known clavius chandra2 contains unusual features like presence three pcmcia slots use dual camcorder batteries source power features intel pentium mmx 233 mhz cpu support 160 mb edo memory built-in hard drive udma support hitachi marketed chandra2 prius note 210 ultraportable thinkpad 240 x z started intel celeron processor went 600 mhz intel pentium iii models using intel 440bx chipset ram expandable 320 mb max bios update screen key pitch standard key pitch also one first thinkpad series contain built-in mini pci card slot form factor 3b 240s optical disc drives external floppy drive optional extended battery sticks bottom like bar props back laptop weighing smallest lightest thinkpads ever made 300-series 300 310 340 350 360 365 380 385 390 various sub-series long-running value series starting 386sl/25 processor way pentium iii 450 300 series offered slightly lower-price alternative 700 series exceptions thinkpad 360pe unique model series could used regular laptop transform tablet flipping monitor top retailing 3,699 1995 360pe featured touch sensitive monitor operated stylus machine could run operating systems supported touch screen pendos 2.2 500-series 500 510 560 e x z 570 e main line ultraportable thinkpads starting 486slc2-50 blue lightning pentium iii 500 machines hard disk board drives external 570 case ultrabase weighed around 600-series 600 600e 600x direct predecessors series 600-series packed svga xga tft lcd pentium mmx pentium ii iii processor full-sized keyboard optical bay package weighing roughly ibm able create light fully featured machine using lightweight strong carbon fiber composite plastics battery shipped 600-series models manufacturing defect left vulnerable memory effect resulted poor battery life problem avoided use third-party battery 700-series 700 701 720 730 tablet 750 755 760 765 770 various sub-models considered cutting-edge intel-based thinkpads featured best screens largest hard drives fastest processors available time first successful thinkpad introduced 1992 first thinkpad tablet pc 700t model without keyboard mouse thinkpad 800-series 800/820/821/822/823/850/851/860 unique based powerpc architecture rather intel x86 architecture 800 series laptops used powerpc 603e cpu speeds 100 mhz 166 mhz 860 model although earliest 800 type 6020 direct ancestor 850 used 603 apparently offered developers units used scsi-2 instead ide hard disks id every scsi device system could configured cursor driven gui-based bios another unusual aspect series unique startup chime reminiscent apple macintosh computers time powerpc thinkpad line considerably expensive standard x86 thinkpads—even modestly configured 850 cost upwards 12,000 hand 800 850 851 later 860 861 capable supporting optional web camera one first commercially available webcams available laptop units could also record pal ntsc signals onboard composite connectors batteries contained internal processors regulate power usage optimized battery longevity powerpc thinkpads could run windows nt 3.5 4.0 os/2 warp connect powerpc edition aix 4.1.x solaris desktop 2.5.1 powerpc edition many powerpc operating systems corresponding compilers scarce hard find however also possible run certain powerpc versions linux 800 series thinkpad series introduced ibm 1999 geared towards multimedia focus many models featuring independent integrated cd players multimedia access buttons 1400 1500 models designed acer ibm contract featured similar hardware found acer laptops including ali chipsets three way audio jacks internal plastics painted copper paint series thinkpads particularly acer developed models prone broken hinges stress damage chassis one notable thinkpad series lineup s3x s30/s31 models featuring unique keyboard lid design allowing standard size keyboard fit chassis otherwise would n't able support protruding keyboard models largely available asia pacific ibm offered optional piano black lid models designed yamato design lab thinkpad since 701c feature special design accommodate keyboard physically larger laptop also thinkpad aside z61 deviate away standard matte lid a-series developed all-around productivity machine equipped hardware powerful enough make desktop replacement hence biggest heaviest thinkpad series time also features even found t-series age a-series dropped favor g-series r-series a31 released 2002 desktop replacement system equipped pentium 4-m processor clocked 1.6 1.8 1.9 2.0 ghz max supported 2.6 ghz ati mobility radeon 7500 128 256 mb pc2100 ram officially upgradable 1 gb unofficially upgraded 2 gb ibm high rate wireless prism 2.5 based modified support wpa-tkip equipped 20 30 40 gb hard disk drive r series budget line beginning r30 2001 ending r400 r500 presented 2008 successor r400 r500 models thinkpad l series l412 l512 models notable model r50p optional 15 ips lcd screen introduced 2003 g-series consisted three models g40 g41 g50 large heavy machines equipped powerful desktop processors line thinkpads consequently served mainly replacements desktop computers z series released high-end multimedia laptop result first thinkpad feature widescreen 16:10 aspect ratio display z-series also unique certain models featured optional titanium lid integrated wwan webcam also found configurations series ever included z60 z60m z60t z61 z61m z61t z61p latter first z-series thinkpad intel yonah dual core technology processor supports intel vt-x disabled bios turned bios update running fully virtualised operating systems via xen vmware therefore possible despite z61 carrying number t61 hardware z61 closer t60 likewise z60 closer t43 15-year anniversary thinkpad model based x60s laptop model initially known inside lenovo scout name horse ridden tonto sidekick 1950s television series lone ranger lenovo envisioned scout high-end thinkpad would analogous luxury car unit covered fine leather embossed owners initials extensive market research conducted consumers would perceive form factor determined appreciated emphasised warmth nature human relations technology scout soon renamed thinkpad reserve edition came bundled premium services including dedicated 24-hour technical support hotline would answered immediately released 2007 sold 5,000 united states sl series launched 2008 low-end thinkpad targeted mainly geared toward small businesses lacked several traditional thinkpad features thinklight magnesium alloy roll cage ultrabay lid latch use 6-row keyboard different layout traditional 7-row thinkpad keyboard also sl-series models ideapad-based firmware models offered included 14 sl400 sl410 15.6 sl500 sl510 13.3 model sl300 previously offered discontinued w series introduced 2008 replace p-suffixed performance series e.g t61p geared towards cad users photographers power users others need high-performance system demanding tasks w530 released june 2012 minimum specifications include intel core i5 i7 cpu 15.6 hd screen nvidia quadro k1000m graphics processor four dimm slots capable accepting maximum 32 gb ram previously available w7xx series 17 widescreen model w500 15.4 16:10 ratio model w510 15.6 16:9 ratio model w520 15.6 16:9 ratio model w700ds w701ds two displays 17 main lcd 10 slide-out secondary lcd w7xx series also available wacom digitizer built palm rest high-performance workstation models offered high-end components quad core cpus higher-end workstation graphics compared t-series powerful thinkpad laptops available w540 retained thinklight ultrabay roll cage lid latch found t-series w540 release marked end lid latch thinklight hot-swappable ultrabays found earlier models thinkpad w series discontinued replaced p series mobile workstations edge series released early 2010 small business consumer-end machines design radical departure compared traditional black boxy thinkpad design glossy surfaces optional matte finish later models rounded corners silver trim also offered red first traditionally black thinkpads like sl series targeted towards small businesses consumers lack roll cage ultrabay lid latch thinklight traditional thinkpads though 2011 e220s e420s thinklights also introduced island-style keyboard significantly different layout models included 12.5 e220 e220s 13.3 edge 13 14 edge 14 e420 e420s 15.6 edge 15 e520 e545 sizes 11.6 edge 11 model offered available united states series positioned mid-range thinkpad offering containing ultrabooks derived edge series august 2013 series includes s531 s440 models cases made aluminum magnesium alloy available silver gunmetal colors lenovo thinkpad twist s230u laptop/tablet computer hybrid aimed high-end users twist gets name screen ability twist manner converts device tablet twist 12.5 screen makes use intel core i7 processor ssd technology lieu hard drive review engadget dana wollman wrote lately feel like reviews windows 8 convertibles end way thinkpad twist plenty going bright ips display good port selection affordable price unrivaled typing experience like thinkpads past also offers useful software features businesses lacking dedicated departments good things road warrior battery barely lasts four hours something tells us twist still appeal lenovo loyalists folks trust thinkpad build quality would n't caught dead using keyboard 're brand-agnostic though windows 8 convertibles comfortable keyboards – mention sharper screens faster performance longer battery life helix convertible laptop satisfying tablet conventional notebook users uses rip flip design allows user detach display replace facing different direction sports 11.6 full hd 1920 × 1080 display support windows 8 multi-touch essential processing hardware contained display assembly multitouch capability detached monitor used standalone tablet computer helix high-end hardware build quality including gorilla glass stylus-based input intel vpro hardware-based security features designed appeal business users review published forbes jason evangelho wrote first laptop owned thinkpad t20 next one may likely thinkpad helix lenovo unveiled ces 2013 sea touch-inspired windows 8 hardware first ultrabook convertible form factor gets everything right first batch windows 8 ultrabooks get high marks inspired designs n't quite flexible enough truly byod bring device solutions lenovo ideapad yoga came close sensation feeling keyboard underneath fingers transformed tablet mode slightly jarring dell xps 12 solved problem clever rotating hinge design wanted ability remove tablet display entirely products thinkpad 13 also known thinkpad s2 mainland china budget model 13-inch screen versions running windows 10 google chrome os options powerful configuration skylake core i7 processor 512gb ssd connectivity includes hdmi usb 3.0 onelink+ usb type-c etc weighs thick 2017 second generation ultrabook model released kaby lake core i7 processor fhd touchscreen available certain countries lineup merged l-series 2018 l380 successor 13 second generation lenovo released 25th anniversary retro thinkpad 25 october 2017 model based t470 difference 7-row classic keyboard layout found −20 series logo received splash colour reminiscent ibm era last thinkpad models 7-row keyboard introduced 2011 september 2017 lenovo announced two thinkpad models featuring amd pro chipset technology – a275 a475 sees revival series nameplate seen since early 2000s thinkpads ibm ownership however likely moniker emphasised uses amd technology rather comparative product segment workstation class previous line n't first time lenovo offered amd derived thinkpad first released alternative premium offering established series x series thinkpads use intel chipsets instead
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Computer architecture
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michael hayden general michael vincent hayden born march 17 1945 retired united states air force four-star general former director national security agency principal deputy director national intelligence director central intelligence agency hayden currently co-chairs bipartisan policy center electric grid cyber security initiative 2017 hayden became national security analyst cnn director national security agency nsa 1999 2005 tenure director oversaw controversial nsa surveillance technological communications persons united states alleged foreign terrorist groups resulted nsa warrantless surveillance controversy april 21 2005 lt. gen hayden confirmed united states senate first principal deputy director national intelligence awarded fourth star-making highest-ranking military intelligence officer armed forces served position dni john negroponte may 26 2006 may 8 2006 hayden nominated position director central intelligence agency following resignation porter j. goss 23 may united states senate select committee intelligence voted 12–3 send nomination senate floor nomination confirmed united states senate 26 may vote 78–15 may 30 2006 following day cia lobby president george w. bush attendance hayden sworn director central intelligence agency july 1 2008 hayden retired air force 41 years service continued serve director cia february 12 2009 received honorary doctorate institute world politics washington d.c. 2009 currently principal chertoff group security consultancy co-founded former homeland security secretary michael chertoff also serves board directors caliburn international military contractor oversees operations homestead temporary shelter unaccompanied children hayden distinguished visiting professor george mason university schar school policy government elected board directors motorola solutions effective january 4 2011 michael vincent hayden born march 17 1945 pittsburgh pennsylvania irish-american couple sadie murray harry v. hayden jr. worked welder pennsylvania manufacturing company sister debby brother harry hayden attended st. peter elementary school 7th 8th grade played quarterback school football team coached late dan rooney son founder pittsburgh steelers former chairman team hayden graduated north catholic high school one first jobs equipment manager steelers went duquesne university pittsburgh earned bachelor arts history 1967 commissioned second lieutenant attended graduate school duquesne master degree modern american history continues avid fan hometown pittsburgh steelers since 1990s traveling wife family least three four games year hayden commissioned duquesne university air force reserve officers training corps program hayden entered active military service 1969 hayden married former jeanine carrier daughter margaret two sons michael liam november 2018 hayden hospitalized suffering stroke hayden served commander air intelligence agency director joint command control warfare center headquartered lackland air force base also served senior staff positions pentagon headquarters u.s. european command stuttgart germany national security council washington d.c. u.s. embassy then-people republic bulgaria prior becoming director national security agency general served deputy chief staff united nations command u.s forces korea yongsan garrison also worked intelligence guam 1996 1997 hayden served commander aia agency 16,000 charged defending exploiting information domain hayden served director national security agency chief central security service fort george g. meade maryland march 1999 april 2005 director nsa chief css responsible combat support agency department defense military civilian personnel stationed worldwide hayden came nsa time great trouble agency internal government analysis indicated suffered lack quality management outdated infrastructure fact soon came board huge part nsa network system crashed several days part plan revitalize agency introduce outside contractors induce lot old managers retire get rid old management structures part plan also included increased openness agency historically one secretive organs government notably allowed james bamford access book body secrets hayden also initially extremely concerned following laws domestic surveillance many reports say 9/11 became concerned stopping terrorism allegedly softened stance domestic surveillance hayden however said believed everything agency effective appropriate lawful 9/11 hayden immediately evacuated non-essential personnel nsa headquarters 9/11 agency greatly increased activity details operations largely hidden played major role wars afghanistan iraq war terror one notable example relationship unmanned aerial vehicle 'drone program may 2006 usa today reported hayden leadership nsa created domestic telephone call database nomination hearings hayden defended actions senator russ feingold others stating relied upon legal advice white house building database supported article two united states constitution executive branch powers president must take care laws faithfully executed overriding legislative branch statutes forbidding warrantless surveillance domestic calls included foreign intelligence surveillance act fisa previously action would required warrant fisa court stated purpose database eavesdrop international communications persons within u.s. individuals groups overseas order locate terrorists hayden also championed trailblazer project transformation project large information technology component project criticized several nsa staffers including privacy protections united states citizens waste money critics included diane roark house intelligence committee nsa workers thomas andrews drake william binney j. kirk wiebe loomis others hayden severely rebuked critics several quit protest investigations nsa inspector general dod inspector general congress trailblazer shut part intelligence reform terrorism prevention act 2004 cia chief longer would run intelligence community instead new office created purpose director national intelligence general hayden became principal deputy director national intelligence may 2005 may 2006 first dni john negroponte january 23 2006 hayden participated news conference youtube video posted michael hayden telling reporters press conference probable cause required searches seizures fourth amendment claiming instead standard whether search seizure reasonable probable cause required warrants whether search seizure deemed unreasonable hayden referred people believed torture cia detainees never yielded useful intelligence interrogation deniers may 8 2006 hayden nominated president george w. bush director central intelligence agency resignation porter j. goss may 5 2006 later confirmed may 26 2006 director 78–15 full u.s. senate vote critics nomination hayden attempts increase domestic surveillance included senator dianne feinstein stated may 11 2006 happen believe way major constitutional confrontation fourth amendment guarantees unreasonable search seizure hayden accused lying congress 2007 testimony cia 'enhanced interrogation program 2007 hayden lobbied allow cia conduct drone strikes purely behavior ground vehicles evidence connection terrorism 2008 hayden warned destabilizing consequences muslim migration europe might raise possibility civil unrest 2013 p5+1 reached nuclear agreement iran hayden said accepted iranian uranium enrichment 2014 senate intelligence committee report cia torture cited email prepared subordinate indicated cia director hayden instructed out-of-date information used briefing congress fewer 100 guantanamo bay detainees would reported september 2013 hayden stressed indisputable legality nsa called edward snowden troubled young man morally arrogant tremendous degree also said prospects russia suspect end like rest defectors went old soviet union isolated bored lonely depressed—and ended alcoholics 2008 native northside neighborhood city pittsburgh named part street going past heinz field honor july 26 2011 hayden inducted air force reserve officer training corps distinguished alumni ceremony maxwell afb alabama officiated lt. gen. allen g. peck commander air university serves member board advisors military cyber professionals association mcpa playing edge one new york times book review 100 notable books 2016
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Computer security
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estonian defence league cyber unit estonian defence league ’ cyber unit kkl group units within certain malevs estonian defense league established 2010 created inspiration 2007 cyberattacks estonia spearheaded informatics scientist ülo jaaksoo focuses defense estonian state private telecommunications infrastructure outside-derived cyberattacks mostly employs volunteer participation professionals kkl headquartered grounds tartu tallinn malevs jointly headed tallinn jaan priisalu tartu kuido külm kkl mission protect estonia high-tech way life protecting information infrastructure thus carrying broad defense goals defence minister jaak aaviksoo publicly suggested desire spread kkl units branches option conscripted estonian military
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Computer security
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zaxxon zaxxon first game employ axonometric projection lent name game axxon axon ometric projection type axonometric projection isometric projection effect simulates three dimensions third-person viewpoint also first arcade game advertised television commercial produced paramount pictures 150,000 world record zaxxon 4,680,740 points scored vernon kalanikaus lā'ie hawai march 15 1982 according twin galaxies intergalactic scoreboard object game hit many targets possible without shot running fuel—which replenished paradoxically blowing fuel drums 300 points blowing satellites gun turrets score 200 500 1,000 points two fortresses fly outer space segment end second fortress boss form zaxxon robot destroying robot rocket six hits firing scores 1,000 otherwise 200 surviving ordeal outer space scene destroying 20 ships scores 1,000 points player ship casts shadow indicate height altimeter also displayed space nothing ship cast shadow walls entrance exit fortress openings ship must right altitude pass within fortress additional walls ship shadow altimeter aid flying successfully extra ship awarded usually 10,000 points thereafter lives 19 levels completed give appear lower right corner screen 1982 1985 zaxxon ported apple ii atari 8-bit family atari 2600 atari 5200 msx zx spectrum commodore 64 dragon 32 colecovision intellivision ibm pc compatibles sega sg-1000 trs-80 color computer trs-80 atari 2600 intellivision ports noticeably different used 3rd-person behind-the-ship 3d perspective instead isometric graphics versions colecovision version programmed coleco staffer lawrence schick first home version use isometric graphics 1983 coleco released table top version zaxxon double-panel vfd screen bandai released 2 zaxxon handhelds one vfd table top european japanese market lcd card game sold worldwide video games 1983 called colecovision version zaxxon coup new system video magazine also praised colecovision version arcade alley column describing one thrilling games available noting passing serious criticism arcade original many players felt needed flying lessons even ghost chance performing well k-power rated color computer version 8 points 10 magazine praised excellent three-dimensional graphics concluded zaxxon game ca n't praised enough softline 1983 called atari 8-bit version superb three-dimensional computer game ... since choplifter game looked impressive magazine also liked graphics apple ii trs-80 versions despite computers hardware limitations predicted zaxxon would long-lived bestseller 1984 magazine readers named game fifth most-popular apple program worst apple program third-worst atari program 1983 ii computing listed zaxxon fourth list top apple ii games late 1985 based sales market-share data 2006 zaxxon games included bonuses sega genesis collection sony playstation 2 psp consoles original zaxxon game included ps2 super zaxxon one available psp zaxxon also included unlockable arcade game sonic ultimate genesis collection xbox 360 playstation 3 arcade version released wii virtual console japan december 15 2009 pal region march 5 2010 north america april 12 2010 zaxxon spawned arcade sequel super zaxxon color scheme different player ship flies faster making game difficult robot end second fortress replaced dragon well original future spy released sega 1984 uses hardware zaxxon similar gameplay realistic military theme 1982 milton bradley made zaxxon board game 1987 zaxxon 3-d released master system console variation made use 3-d glasses add-on extra depth perception atari 2600 intellivision ports forward-scrolling rather isometric october 1993 atari corporation filed lawsuit sega alleged infringement patent originally created atari corp. 1980s former seeking preliminary injunction stop manufacturing usage sales hardware software sega genesis game gear september 28 1994 parties reached settlement involved cross-licensing agreement publish five titles year across systems 2001 zaxxon 3-d one first five titles approved deal sega order converted atari jaguar never released zaxxon motherbase 2000 released sega 32x 1995 first zaxxon game incorporate polygon graphics game bore zaxxon brand united states japanese version named parasquad european version named motherbase u.s. gaming critics generally remarked game similar enough zaxxon justify use brand zaxxon escape released october 4 2012 ios android devices game criticized little resemblance original bootleg released arcades 1982 called jackson unauthorized adaptations game published ti 99/4a arcturus amstrad cpc zaxx bbc micro fortress 1984 trs-80 color computer zakssund 1983 hostile terrain encounter h.a.t.e zaxxon clone developed vortex software several 8-bit 16-bit computers published gremlin graphics 1989 2012 zaxxon shown art video games exhibition smithsonian home video game console port zaxxon shown music video new order track blue monday character tommy jarvis played corey feldman paramount feature film seen playing zaxxon character introduction zaxxon featured plot device 1986 independent feature film hollywood zap zaxxon seen numerous times video gamed-themed storyline show remington steele episode steele waters run deep npr podcast pop culture happy hour holds hosts zaxxon rule wherein forbidden bring topics unrelatable audience events one personal life season 1 episode alley abc sitcom home improvement randy plays zaxxon bowling alley attempting set record bully tries stop playing
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Computer architecture
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microsoft tinker tinker also known microsoft tinker puzzle video game developed fuel industries player controls robot various mazes obstacle courses originally released september 23 2008 part windows ultimate extras contained 60 levels including 20-level tutorial free map editor level builder also released however compatible games windows – live version tinker compatible windows ultimate extras version december 15 2009 expanded live-enabled version game released games windows – live client game available windows xp windows vista windows 7 including users access windows vista ultimate extras windows vista editions contains 160 levels including tutorial version also 15 achievements worth 200g similar many xbox live arcade games like every games windows live game requires user sign using gamertag assigned windows live id however windows vista ultimate extras version requirement tinker spatial/environmental puzzle game players must guide robot end point moving objects activating switches traversing obstacles playing field square board divided checkerboard pattern robot given limited number moves make runs energy player must guide goal marker without expiring motions essentially action robot makes counts move including taking step activating switch turning around players must carefully plan actions stage waste moves players replenish robot energy collecting batteries thus extend possible number moves allowed make players earn achievement star level completing course par time energy cog collection cogs exist level obstacles objects present levels include movable objects pushed pulled two objects row pushed even movable objects stacked top pushed bottom object movable e.g. tower consisting two dice blocks metal block moved one dice blocks bottom attempting push immovable object row objects result wasted move though attempting walk obstacle waste move robot destroyed rendered inoperable hit laser beam falling height greater two blocks running energy hazards destroy robot process reaching exit e.g. robot walks laser beam crosses exit square hazard trumps exit robot destroyed however level completed exit reached zero energy live-enabled version tinker previously possible earn achievement star set 07 level 19 due energy par value -1 player could unlock perfection achieved achievement thus able obtain 175 achievement points 200 fuel industries game developer nick iannitti mentioned tinker blog fix sent gfwl march 7 2010 fix hours removed due bug auto-update code required unnecessary reboot update officially released april 10 2010 making perfection achieved achievement obtainable
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Operating systems
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time-based one-time password algorithm time-based one-time password algorithm totp extension hmac-based one-time password algorithm hotp generating one-time password instead taking uniqueness current time adopted internet engineering task force standard rfc 6238 cornerstone initiative open authentication oath used number two-factor authentication systems latency network human unsynchronised clocks one-time password must validate range times authenticator authenticated time downsampled larger durations e.g. 30 seconds allow validity parties however hotp decreased uniqueness requires additional countermeasures rate limiting establish totp authentication authenticated authenticator must pre-establish hotp parameters following totp parameters authenticator authenticatee compute totpvalue authenticator checks totpvalue supplied authenticated matches locally-generated totpvalue authenticators allow values generated current time order account slight clock skews network latency user delays totp uses hotp algorithm substituting counter non-decreasing value based current time time counter c integer counting number durations difference current unix time epoch cf unix epoch latter values integer seconds note unix time strictly increasing specifically leap seconds inserted utc subsequent authentications work clocks authenticated authenticator need roughly synchronized authenticator typically accept one-time passwords generated timestamps differ ±1 time interval authenticated timestamp totpvalues phished passwords though require attackers proxy credentials real time rather collect later time implementations n't limit login attempts vulnerable brute forcing values attacker steals shared secret generate new valid totpvalues particular problem attacker breaches large authentication database totp devices batteries go flat clocks de-sync totp software versions run phones lost and/or stolen real-world implementations methods bypass protection e.g printed codes email-resets etc. cause considerable support burden large user-bases also gives fraudulent users additional vectors exploit totpvalues valid longer amount time show screen typically twice long concession authenticating authenticated sides clocks skewed large margin totp draft developed collaboration several oath members order create industry-backed standard complements event-based one-time standard hotp offers end user organizations enterprises choice selecting technologies best fit application requirements security guidelines 2008 oath submitted draft version specification ietf version incorporates feedback commentary authors received technical community based prior versions submitted ietf may 2011 totp officially became rfc 6238
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Internet protocols
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burp suite burp burp suite graphical tool testing web application security tool written java developed portswigger web security tool three editions community edition downloaded free charge professional edition enterprise edition purchased trial period community edition significantly reduced functionality developed provide comprehensive solution web application security checks addition basic functionality proxy server scanner intruder tool also contains advanced options spider repeater decoder comparer extender sequencer company behind burp suite also developed mobile application containing similar tools compatible ios 8 portswigger founded 2004 dafydd stuttard leading expert web security also authored popular manual web application security
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Computer security
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corpus electronic texts corpus electronic texts celt online database contemporary historical documents relating irish history culture 8 december 2016 celt contained 1,601 documents total 18 million words 1992 celt originated ashes unsuccessful partnership university college cork ucc/nui royal irish academy ria project named curia according celt database caters academic scholars teachers students general public world
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Databases
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file system file system bfs native file system beos linux kernel referred befs avoid confusion boot file system bfs developed dominic giampaolo cyril meurillon ten-month period starting september 1996 provide beos modern 64-bit capable journaling file system case-sensitive capable used floppy hard disks read-only media cd-roms however use small removable media advised file-system headers consume 600 kb 2 mb rendering floppy disks virtually useless like predecessor ofs old file system written benoit schillings formerly bfs includes support extended file attributes metadata indexing querying characteristics provide functionality similar relational database whilst intended 64-bit-capable file system size on-disk structures mean practical size limit approximately 2 exabytes similarly extent-based file allocation reduces maximum practical file size approximately 260 gigabytes best little blocks pathological worst case depending degree fragmentation design process application programming interface internal workings part documented book practical file system design file system addition original 1996 bfs used beos several implementations linux early 1999 makoto kato developed file system driver linux however driver never reached complete stable state 2001 dyson developed version linux bfs driver 2002 axel dörfler developers created released reimplemented bfs called openbfs haiku openbeos back january 2004 robert szeleney announced developed fork openbfs file system use skyos operating system regular openbfs implementation also ported syllable included since version 0.6.5
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Computer file systems
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immediately invoked function expression immediately invoked function expression iife pronounced iffy javascript programming language idiom produces lexical scope using javascript function scoping immediately invoked function expressions used avoid variable hoisting within blocks protect polluting global environment simultaneously allow public access methods retaining privacy variables defined within function immediately invoked function expressions may written number different ways common convention enclose function expressionand optionally invocation operatorwith grouping operator parentheses tell parser explicitly expect expression otherwise situations parser encounters codice_1 keyword treats function declaration statement function expression function /* ... */ function /* ... */ ways enforce function expression function /* ... */ ~function /* ... */ -function /* ... */ +function /* ... */ void function /* ... */ contexts expression expected wrapping parentheses necessary var f function /* ... */ true function /* ... */ 0 function /* ... */ passing variables scope done follows function b /* ... */ hello world initial parenthesis one case automatic semicolon insertion asi javascript cause problems expression instead interpreted call last term preceding line styles omit optional semicolons semicolon placed front parenthesis known defensive semicolon example b c // code ... avoid parsed codice_2 key understanding design patterns iife realize prior es6 javascript featured function scope thus lacking block scope passing values reference inside closures longer case es6 version javascript implements block scoping using new codice_3 codice_4 keywords lack block scope means variables defined inside example loop definition hoisted top enclosing function evaluating function depends variables modified outer function including iteration difficult see without loop update value defining invoking function var v getvalue v 1 getvalue function return v v 2 getvalue // 2 result may seem obvious updating codice_5 manually produce unintended results codice_6 defined inside loop hereafter function passes codice_5 argument invoked immediately preserving inner function execution context var v getvalue v 1 getvalue function x v v 2 getvalue // 1 equivalent following code var v getvalue v 1 function f x getvalue f v v 2 getvalue // 1 david herman effective javascript contains example illustrating problems evaluation context inside loops herman example deliberately convoluted arises directly lack block scope iifes also useful establishing private methods accessible functions still exposing properties later use following example comes alman post iifes // counter function returns object properties case functions var counter function // calls access function properties returned counter counter.get // 0 counter.set 3 counter.increment // 4 counter.increment // 5 attempt access codice_8 global environment undefined enclosed within invoked function property codice_9 likewise attempt access codice_10 result error declared codice_10 global environment originally known self-executing anonymous function ben alman later introduced current term iife semantically accurate name idiom shortly discussion arose comp.lang.javascript notably immediately invoked functions need anonymous inherently ecmascript5 strict mode forbids codice_12 rendering original term misnomer
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Programming language topics
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boot disk boot disk removable digital data storage medium computer load run boot operating system utility program computer must built-in program load execute program boot disk meeting certain standards almost modern computers boot hard drive containing operating system software would normally called boot disks removable media cd-roms common forms media used media magnetic paper tape drives zip drives recently usb flash drives used computer bios must support booting device question boot disks used term boot comes idea lifting oneself one bootstraps computer contains tiny program bootstrap loader load run program found boot device program may small program designed load larger capable program i.e. full operating system enable booting without requirement either mass storage device write boot medium usual boot program use system ram ram disk temporary file storage example computer compatible ibm pc able built-in software load contents first 512 bytes floppy execute viable program boot floppies simple loader program bytes process vulnerable abuse data floppies could virus written first sector silently infects host computer switched disk drive bootable floppy disks boot floppies pcs usually contain dos miniature versions linux commonly available floppy disk hold 1.4 mb data standard format making impractical loading large operating systems use boot floppies decline due availability higher-capacity options cd-roms usb flash drives modern pc configured attempt boot various devices certain order computer booting device desired floppy drive user may enter bios setup function pressing special key computer first turned delete f1 f2 f10 f12 changing boot order recent bioses permit interruption final stage boot process pressing function key usually f11 results list bootable devices presented selection may made modern apple computers boot appropriate disk user presses c key machine starting different operating systems use different boot disk contents boot disks must compatible computer designed files must version operating system complete boot disks prepared one operation installed operating system details vary
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Operating systems
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disk sector computer disk storage sector subdivision track magnetic disk optical disc sector stores fixed amount user-accessible data traditionally 512 bytes hard disk drives hdds 2048 bytes cd-roms dvd-roms newer hdds use 4096-byte 4 kib sectors known advanced format af sector minimum storage unit hard drive disk partitioning schemes designed files occupy integral number sectors regardless file actual size files fill whole sector remainder last sector filled zeroes practice operating systems typically operate blocks data may span multiple sectors geometrically word sector means portion disk center two radii corresponding arc see figure 1 item b shaped like slice pie thus disk sector figure 1 item c refers intersection track geometrical sector modern disk drives physical sector made two basic parts sector header area typically called id data area sector header contains information used drive controller information includes sync bytes address identification flaw flag error detection correction information header may also include alternate address used data area undependable address identification used ensure mechanics drive positioned read/write head correct location data area contains sync bytes user data error-correcting code ecc used check possibly correct errors may introduced data first disk drive 1957 ibm 350 disk storage ten 100 character sectors per track character six bits included parity bit number sectors per track identical recording surfaces recorded identifier field id associated sector 1961 ibm 1301 disk storage introduced variable length sectors termed records ibm added record record address field separate data record sector modern disk drives sector address fields called id fields separate data sector also 1961 bryant 4000 series introduced concept zoned recording allowed number sectors per track vary function track diameter sectors outer track inner track became industry practice 1990s standard today disk drives announced ibm system/360 1964 detected errors fields sectors records cyclic redundancy check crc replacing parity per character detection prior generations ibm sectors records time added third field physical sector key field aid searching data ibm physical sectors called records three basic parts count field acts id field key field present disk drive sectors data field frequently called ckd format record 1970 ibm 3330 disk storage replaced crc data field sector error correcting code ecc improve data integrity detecting errors allowing correction many errors ultimately fields disk sectors eccs prior 1980s little standardization sector sizes disk drives maximum number bits per track various system manufacturers subdivided track different sector sizes suit oses applications popularity pc beginning 1980s advent ide interface late 1980s led 512-byte sector becoming industry standard sector size hdds similar storage devices 1970s ibm added fixed-block architecture direct access storage devices fba dasds line ckd dasd ckd dasd supported multiple variable length sectors ibm fba dasd supported sector sizes 512 1024 2048 4096 bytes 2000 industry trade organization international disk drive equipment materials association idema started work define implementation standards would govern sector size formats exceeding 512 bytes accommodate future increases data storage capacities.by end 2007 anticipation future idema standard samsung toshiba began shipments 1.8-inch hard disk drives 4096 byte sectors 2010 idema completed advanced format standard 4096 sector drives setting date transition 512 4096 byte sectors january 2011 manufacturers advanced format drives soon became prevalent sector specifically means physical disk area term block used loosely refer small chunk data block multiple meanings depending context context data storage filesystem block abstraction disk sectors possibly encompassing multiple sectors contexts may unit data stream unit operation utility example unix program dd allows one set block size used execution parameter codice_1 specifies size chunks data delivered dd unrelated sectors filesystem blocks linux disk sector size determined codice_2 block size determined codice_3 sector defined intersection radius track case early hard drives floppy disks sectors towards outside disk physically longer nearer spindle sector still contains number bytes outer sectors lower bit density inner ones inefficient use magnetic surface solution zone bit recording wherein disk divided zones encompassing small number contiguous tracks zone divided sectors sector similar physical size outer zones greater circumference inner zones allocated sectors known zoned bit rate consequence zone bit recording contiguous reads writes noticeably faster outer tracks corresponding lower block addresses inner tracks bits pass head rotation difference 25 1998 traditional 512-byte sector size identified one impediment increasing capacity time growing rate exceeding moore law increasing length data field implementation advanced format using 4096-byte sectors removed impediment increased efficiency data surface area five thirteen percent increasing strength ecc turn allowed higher capacity format standardized industry consortium 2005 2011 incorporated new products hard drive manufacturers
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Computer file systems
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lexical choice lexical choice subtask natural language generation involves choosing content words nouns verbs adjectives adverbs generated text function words determiners example usually chosen realisation simplest type lexical choice involves mapping domain concept perhaps represented ontology word example concept finger might mapped word finger complex situation domain concept expressed using different words different situations example domain concept value-change expressed many ways sometimes words communicate additional contextual information example contextual information especially significant vague terms tall example 2m tall man tall 2m tall horse small lexical choice modules must informed linguistic knowledge system input data maps onto words question semantics also influenced syntactic factors collocation effects pragmatic factors context hence nlg systems need linguistic models meaning mapped words target domain genre nlg system genre tends important example verb veer specific meaning weather forecasts wind direction changing clockwise direction general english weather-forecast generator must aware genre-specific meaning cases major differences different people use word example people use evening mean 6pm others use mean midnight psycholinguists shown people speak agree common interpretation via lexical alignment something nlg systems yet ultimately lexical choice must deal fundamental issue language relates non-linguistic world example system chose colour terms red describe objects digital image would need know rgb pixel values could generally described red influenced visual lighting objects scene linguistic objects discussed context pragmatic connotations associated red example apple called red assumed ripe well colour red forth number algorithms models developed lexical choice research community example edmonds developed model choosing near-synonyms words similar core meanings different connotations however algorithms models widely used applied nlg systems systems instead often used quite simple computational models invested development effort linguistic analysis instead algorithm development
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Computational linguistics
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p6 microarchitecture p6 microarchitecture sixth-generation intel x86 microarchitecture implemented pentium pro microprocessor introduced november 1995 frequently referred i686 succeeded netburst microarchitecture 2000 eventually revived pentium line microprocessors successor pentium variant p6 microarchitecture core microarchitecture turn also derived p6 microarchitecture p6 core sixth generation intel microprocessor x86 line first implementation p6 core pentium pro cpu 1995 immediate successor original pentium design p5 p6 processors dynamically translate ia-32 instructions sequences buffered risc-like micro-operations analyze reorder micro-operations order detect parallelizable operations may issued one execution unit pentium pro first x86 chip use technique — nexgen nx586 introduced 1994 also used — first intel x86 chip techniques first used x86 space p6 core include p6 architecture lasted three generations pentium pro pentium iii widely known low power consumption excellent integer performance relatively high instructions per cycle ipc p6 line processing cores succeeded netburst p68 architecture appeared introduction pentium 4 completely different design based use long pipelines favoured high clock speed cost lower ipc higher power consumption upon release pentium 4-m mobile pentium 4 quickly realized new mobile netburst processors ideal mobile computing netburst-based processors simply efficient per clock per watt compared p6 predecessors mobile pentium 4 processors ran much hotter pentium iii-m processors n't offer significant performance advantages inefficiency affected cooling system complexity also all-important battery life realizing new microarchitecture n't best choice mobile space intel went back drawing board design would optimally suited market segment result modernized p6 design called pentium design overview pentium power efficient x86 processor notebooks several years consuming maximum 27 watts maximum load 4-5 watts idle processing efficiency gains brought modernization allowed rival mobile pentium 4 clocked 1 ghz higher fastest-clocked mobile pentium 4 compared fastest-clocked pentium equipped much memory bus bandwidth first pentium family processors banias internally support pae show pae support flag cpuid information causes operating systems primarily linux distributions refuse boot processors since pae support required kernels yonah cpu launched january 2006 core brand single dual-core mobile version sold core solo core duo pentium dual-core brands server version released xeon lv processors provided partial solutions pentium shortcomings adding resulted interim microarchitecture low-voltage cpus part way p6 following core microarchitecture july 27 2006 core microarchitecture derivative p6 launched form core 2 processor subsequently processors released core microarchitecture core 2 xeon pentium celeron brand names core microarchitecture intel final mainstream processor line use fsb later intel processors based nehalem later intel microarchitectures featuring integrated memory controller qpi dmi bus communication rest system improvements relative intel core processors chips technically derivatives pentium pro architecture gone several radical changes since inception
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Computer architecture
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data link connection identifier data link connection identifier dlci frame relay 10-bit-wide link-local virtual circuit identifier used assign frames specific pvc svc frame relay networks use dlcis statistically multiplex frames dlcis preloaded switch act road signs traveling frames standard allows existence 1024 dlcis dlci 0 reserved ansi/q993a lmi standard—only numbers 16 976 usable end-user equipment dlci 1023 reserved cisco lmi however numbers 16 1007 usable summary using cisco lmi numbers 16 1007 available end-user equipment rest reserved various management purposes dlci layer 2 addresses locally significant two devices dlci mapped interface one frame relay cloud
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Internet protocols
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freescale 683xx freescale 683xx formerly motorola 683xx family compatible microcontrollers use motorola 68000-based cpu core family designed using hardware description language making parts synthesizable amenable improved fabrication processes die shrinks two cpu cores used 683xx family 68ec000 cpu32 instruction set cpu32 core similar 68020 without bitfield instructions instructions unique cpu32 core table lookup interpolate instructions low-power stop mode modules microcontroller designed independently released new cpus could tested process let architects perform design-ahead silicon technologies available motorola designs ready implement go market many submodules carried forward coldfire line processors microcontrollers consist series modules connected internal bus modules available various processors 683xx family
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Computer architecture
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scareware scareware form malware uses social engineering cause shock anxiety perception threat order manipulate users buying unwanted software scareware part class malicious software includes rogue security software ransomware scam software tricks users believing computer infected virus suggests download pay fake antivirus software remove usually virus fictional software non-functional malware according anti-phishing working group number scareware packages circulation rose 2,850 9,287 second half 2008 first half 2009 apwg identified 585 increase scareware programs scareware label also apply application virus pranks users intent cause anxiety panic internet security writers use term scareware describe software products produce frivolous alarming warnings threat notices typically fictitious useless commercial firewall registry cleaner software class program tries increase perceived value bombarding user constant warning messages increase effectiveness way software packaged look feel mimics legitimate security software order deceive consumers websites display pop-up advertisement windows banners text computer may infected harmful spyware programs immediate removal may required scan click 'yes websites go far saying user job career marriage would risk products using advertisements often considered scareware serious scareware applications qualify rogue software scareware affiliated installed programs user encounter pop-up website indicating pc infected scenarios possible become infected scareware even user attempts cancel notification popups especially designed look like come user operating system actually webpage 2010 study google found 11,000 domains hosting fake anti-virus software accounting 50 malware delivered via internet advertising starting march 29 2011 1.5 million web sites around world infected lizamoon sql injection attack spread scareware research google discovered scareware using servers check internet connectivity data suggested million machines infected scareware company placed warning search results users whose computers appear infected another example scareware smart fortress site scares people thinking lots viruses computer asks buy professional service forms spyware also qualify scareware change user desktop background install icons computer notification area microsoft windows claiming kind spyware infected user computer scareware application help remove infection cases scareware trojans replaced desktop victim large yellow text reading warning spyware box containing similar text even forced screensaver change bugs crawling across screen winwebsec term usually used address malware attacks users windows operating system produces fake claims similar genuine anti-malware software spysheriff exemplifies spyware scareware purports remove spyware actually piece spyware often accompanying smitfraud infections antispyware scareware may promoted using phishing scam another approach trick users uninstalling legitimate antivirus software microsoft security essentials disabling firewall since antivirus programs typically include protection tampered disabled software scareware may use social engineering convince user disable programs would otherwise prevent malware working 2005 microsoft washington state successfully sued secure computer makers spyware cleaner 1 million charges using scareware pop-ups washington attorney general also brought lawsuits securelink networks high falls media makers quick shield october 2008 microsoft washington attorney general filed lawsuit two texas firms branch software alpha red producers registry cleaner xp scareware lawsuit alleges company sent incessant pop-ups resembling system warnings consumers personal computers stating critical error message registry damaged corrupted instructing users visit web site download registry cleaner xp cost 39.95 december 2 2008 u.s. federal trade commission ftc filed complaint federal court innovative marketing inc. bytehosting internet services llc well individuals sam jain daniel sundin james reno marc ’ souza kristy ross complaint also listed maurice ’ souza relief defendant alleged held proceeds wrongful conduct accusing violating law ftc alleged defendants violated ftc act deceptively marketing software including winfixer winantivirus drivecleaner errorsafe xp antivirus according complaint defendants falsely represented scans consumer computer showed compromised infected offered sell software fix alleged problems another type scareware involves software designed literally scare user use unanticipated shocking images sounds video
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Computer security
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setcontext setcontext one family c library functions others getcontext makecontext swapcontext used context control codice_1 family allows implementation c advanced control flow patterns iterators fibers coroutines may viewed advanced version setjmp/longjmp whereas latter allows single non-local jump stack codice_1 allows creation multiple cooperative threads control stack codice_1 specified posix.1-2001 single unix specification version 2 unix-like operating systems provide posix.1-2004 obsoleted functions posix.1-2008 removed posix threads indicated possible replacement citing ieee std 1003.1 2004 edition incorporation iso/iec 9899:1999 standard specification found iso c standard subclause 6.11.6 specifies use function declarators empty parentheses obsolescent feature therefore using function prototype making use obsolescent feature iso c standard therefore strictly conforming posix application use form therefore use getcontext makecontext swapcontext marked obsolescent way iso c standard specify non-obsolescent function prototype indicating function called arbitrary number including zero arguments arbitrary types including integers pointers data pointers functions composite types functions associated types defined codice_4 system header file includes codice_5 type four functions operate codice_6 points context resumed current context exits context created codice_7 secondary context codice_8 used store set signals blocked context codice_9 stack used context codice_10 stores execution state including registers cpu flags instruction pointer stack pointer codice_11 opaque type functions example demonstrates iterator using codice_1 note example correct may work intended cases function codice_7 requires additional parameters type codice_36 example passes pointers thus example may fail 64-bit machines specifically lp64-architectures problem worked around breaking reconstructing 64-bit values introduces performance penalty get set context smaller context handy makes infinite loop context holds program counter
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Operating systems
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l2tpv3 layer 2 tunnelling protocol version 3 ietf standard related l2tp used alternative protocol multiprotocol label switching mpls encapsulation multiprotocol layer 2 communications traffic ip networks like l2tp l2tpv3 provides pseudo-wire service scaled fit carrier requirements l2tpv3 regarded mpls ip atm simplified version concept much benefit achieved fraction effort cost losing technical features considered less important market case l2tpv3 features lost teletraffic engineering features considered important mpls however reason features could re-engineered top l2tpv3 later products protocol overhead l2tpv3 also significantly bigger mpls
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Internet protocols
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ibm international business machines corporation ibm american multinational information technology company headquartered armonk new york operations 170 countries company began 1911 founded endicott new york computing-tabulating-recording company ctr renamed international business machines 1924 ibm produces sells computer hardware middleware software provides hosting consulting services areas ranging mainframe computers nanotechnology ibm also major research organization holding record u.s. patents generated business 26 consecutive years inventions ibm include automated teller machine atm floppy disk hard disk drive magnetic stripe card relational database sql programming language upc barcode dynamic random-access memory dram ibm mainframe exemplified system/360 dominant computing platform 1960s 1970s ibm continually shifted business operations focusing higher-value profitable markets includes spinning printer manufacturer lexmark 1991 sale personal computer thinkpad/thinkcentre x86-based server businesses lenovo 2005 2014 respectively acquiring companies pwc consulting 2002 spss 2009 weather company 2016 red hat 2019 also 2015 ibm announced would go fabless continuing design semiconductors offloading manufacturing globalfoundries nicknamed big blue ibm one 30 companies included dow jones industrial average one world largest employers 380,000 employees known ibmers least 70 ibmers based outside united states country largest number ibmers india ibm employees awarded five nobel prizes six turing awards ten national medals technology usa five national medals science usa 1880s technologies emerged would ultimately form core international business machines ibm julius e. pitrap patented computing scale 1885 alexander dey invented dial recorder 1888 herman hollerith 1860–1929 patented electric tabulating machine willard bundy invented time clock record worker arrival departure time paper tape 1889 june 16 1911 four companies amalgamated new york state charles ranlett flint forming fifth company computing-tabulating-recording company ctr based endicott new york five companies 1,300 employees offices plants endicott binghamton new york dayton ohio detroit michigan washington d.c. toronto manufactured machinery sale lease ranging commercial scales industrial time recorders meat cheese slicers tabulators punched cards thomas j. watson sr. fired national cash register company john henry patterson called flint 1914 offered position ctr watson joined ctr general manager 11 months later made president court cases relating time ncr resolved learned patterson pioneering business practices watson proceeded put stamp ncr onto ctr companies implemented sales conventions generous sales incentives focus customer service insistence well-groomed dark-suited salesmen evangelical fervor instilling company pride loyalty every worker favorite slogan think became mantra company employees watson first four years revenues reached 9 million company operations expanded europe south america asia australia watson never liked clumsy hyphenated name computing-tabulating-recording company february 14 1924 chose replace expansive title international business machines 1933 subsidiaries merged one company ibm 1937 ibm tabulating equipment enabled organizations process unprecedented amounts data clients including u.s. government first effort maintain employment records 26 million people pursuant social security act tracking persecuted groups hitler third reich largely german subsidiary dehomag 1949 thomas watson sr. created ibm world trade corporation subsidiary ibm focused foreign operations 1952 stepped almost 40 years company helm son thomas watson jr. named president 1956 company demonstrated first practical example artificial intelligence arthur l. samuel ibm poughkeepsie new york laboratory programmed ibm 704 merely play checkers learn experience 1957 fortran scientific programming language developed 1961 ibm developed sabre reservation system american airlines introduced highly successful selectric typewriter 1963 ibm employees computers helped nasa track orbital flights mercury astronauts year later moved corporate headquarters new york city armonk new york latter half 1960s saw ibm continue support space exploration participating 1965 gemini flights 1966 saturn flights 1969 lunar mission april 7 1964 ibm announced first computer system family ibm system/360 spanned complete range commercial scientific applications large small allowing companies first time upgrade models greater computing capability without rewrite applications followed ibm system/370 1970 together 360 370 made ibm mainframe dominant mainframe computer dominant computing platform industry throughout period early 1980s operating systems ran os/vs1 mvs middleware built top cics transaction processing monitor near-monopoly-level hold computer industry became almost synonymous ibm products due marketshare 1974 ibm engineer george j. laurer developed universal product code ibm world bank first introduced financial swaps public 1981 entered swap agreement ibm pc originally designated ibm 5150 introduced 1981 soon became industry standard 1991 ibm spun printer manufacturing new business called lexmark 1993 ibm posted us 8 billion loss – time biggest american corporate history lou gerstner hired ceo rjr nabisco turn company around 2002 ibm acquired pwc consulting 2003 initiated project redefine company values hosting three-day online discussion key business issues 50,000 employees result three values dedication every client success innovation matters—for company world trust personal responsibility relationships 2005 company sold personal computer business chinese technology company lenovo 2009 acquired software company spss inc. later 2009 ibm blue gene supercomputing program awarded national medal technology innovation u.s. president barack obama 2011 ibm gained worldwide attention artificial intelligence program watson exhibited jeopardy game-show champions ken jennings brad rutter company also celebrated 100th anniversary year june 16 2012 ibm announced agreed buy kenexa year later also acquired softlayer technologies web hosting service deal worth around 2 billion 2014 ibm announced would sell x86 server division lenovo 2.1 billion also year ibm began announcing several major partnerships companies including apple inc. twitter facebook tencent cisco underarmour box microsoft vmware csc macy sesame workshop parent company sesame street salesforce.com 2015 ibm announced three major acquisitions merge healthcare 1 billion data storage vendor cleversafe digital assets weather company including weather.com weather channel mobile app also year ibmers created film boy atom first molecule movie tell story 2016 ibm acquired video conferencing service ustream formed new cloud video unit april 2016 posted 14-year low quarterly sales following month groupon sued ibm accusing patent infringement two months ibm accused groupon patent infringement separate lawsuit 2015 ibm bought digital part weather company october 2018 ibm announced intention acquire red hat 34 billion acquisition completed july 9 2019 june 2019 ibm cut 2,000 jobs ibm headquartered armonk new york community north midtown manhattan principal building referred chq glass stone edifice parcel amid 432-acre former apple orchard company purchased mid-1950s two ibm buildings within walking distance chq north castle office previously served ibm headquarters louis v. gerstner jr. center learning formerly known ibm learning center ilc resort hotel training center 182 guest rooms 31 meeting rooms various amenities ibm operates 174 countries mobility centers smaller markets areas major campuses larger ones new york city ibm several offices besides chq including ibm watson headquarters astor place manhattan outside new york major campuses united states include austin texas research triangle park raleigh-durham north carolina rochester minnesota silicon valley california ibm real estate holdings varied globally diverse towers occupied ibm include 1250 rené-lévesque montreal canada tour descartes paris france one atlantic center atlanta georgia usa beijing china ibm occupies pangu plaza city seventh tallest building overlooking beijing national stadium bird nest home 2008 summer olympics ibm india private limited indian subsidiary ibm headquartered bengaluru karnataka facilities bengaluru ahmedabad delhi kolkata mumbai chennai pune gurugram noida bhubaneshwar coimbatore visakhapatnam hyderabad notable buildings include ibm rome software lab rome italy hursley house winchester uk 330 north wabash chicago illinois united states cambridge scientific center cambridge massachusetts united states ibm toronto software lab toronto canada ibm building johannesburg johannesburg south africa ibm building seattle seattle washington united states ibm hakozaki facility tokyo japan ibm yamato facility yamato japan ibm canada head office building ontario canada watson iot headquarters munich germany defunct ibm campuses include ibm somers office complex somers new york company contributions industrial architecture design include works eero saarinen ludwig mies van der rohe i.m pei van der rohe building chicago recognized 1990 honor award national building museum ibm recognized one top 20 best workplaces commuters united states environmental protection agency epa 2005 recognized fortune 500 companies provided employees excellent commuter benefits help reduce traffic air pollution 2004 concerns raised related ibm contribution early days pollution original location endicott new york fiscal year 2017 ibm reported earnings us 5.7 billion annual revenue us 79.1 billion decline 1.0 previous fiscal cycle ibm shares traded 125 per share market capitalization valued us 113.9 billion september 2018 ibm ranked 34 2018 fortune 500 rankings largest united states corporations total revenue ibm large diverse portfolio products services offerings fall categories cloud computing artificial intelligence commerce data analytics internet things iot infrastructure mobile security ibm cloud includes infrastructure service iaas software service saas platform service paas offered public private hybrid cloud delivery models instance ibm bluemix paas enables developers quickly create complex websites pay-as-you-go model ibm softlayer dedicated server managed hosting cloud computing provider 2011 reported hosting 81,000 servers 26,000 customers ibm also provides cloud data encryption services icdes using cryptographic splitting secure customer data ibm also hosts industry-wide cloud computing mobile technologies conference interconnect year hardware designed ibm categories include ibm power microprocessors employed inside many console gaming systems including xbox 360 playstation 3 nintendo wii u. ibm secure blue encryption hardware built microprocessors 2014 company revealed truenorth neuromorphic cmos integrated circuit announced 3 billion investment following five years design neural chip mimics human brain 10 billion neurons 100 trillion synapses uses 1 kilowatt power 2016 company launched all-flash arrays designed small midsized companies includes software data compression provisioning snapshots across various systems outsourcing also represents major service provided ibm 40 data centers worldwide alphaworks ibm source emerging software technologies spss software package used statistical analysis ibm kenexa suite provides employment retention solutions includes brassring applicant tracking system used thousands companies recruiting ibm also owns weather company provides weather forecasting includes weather.com weather underground smarter planet initiative seeks achieve economic growth near-term efficiency sustainable development societal progress targeting opportunities smart grids water management systems solutions traffic congestion greener buildings services provisions include redbooks publicly available online books best practices ibm products developerworks website software developers professionals how-to articles tutorials well software downloads code samples discussion forums podcasts blogs wikis resources developers technical professionals ibm watson technology platform uses natural language processing machine learning reveal insights large amounts unstructured data watson debuted 2011 american game-show jeopardy competed champions ken jennings brad rutter three-game tournament watson since applied business healthcare developers universities example ibm partnered memorial sloan kettering cancer center assist considering treatment options oncology patients melanoma screenings also several companies begun using watson call centers either replacing assisting customer service agents january 2019 ibm introduced first commercial quantum computer ibm q system one ibm also provides infrastructure new york city police department ibm cognos analytics perform data visualizations compstat crime data research part ibm since founding organized efforts trace roots back 1945 watson scientific computing laboratory founded columbia university new york city converting renovated fraternity house manhattan west side ibm first laboratory ibm research constitutes largest industrial research organization world 12 labs 6 continents ibm research headquartered thomas j. watson research center new york facilities include almaden lab california austin lab texas australia lab melbourne brazil lab são paulo rio de janeiro china lab beijing shanghai ireland lab dublin haifa lab israel india lab delhi bangalore tokyo lab zurich lab africa lab nairobi terms investment ibm r expenditure totals several billion dollars year 2012 expenditure approximately us 6.9 billion recent allocations included 1 billion create business unit watson 2014 3 billion create next-gen semiconductor along 4 billion towards growing company strategic imperatives cloud analytics mobile security social 2015 ibm leading proponent open source initiative began supporting linux 1998 company invests billions dollars services software based linux ibm linux technology center includes 300 linux kernel developers ibm also released code different open source licenses platform-independent software framework eclipse worth approximately us 40 million time donation three-sentence international components unicode icu license java-based relational database management system rdbms apache derby ibm open source involvement trouble-free however see sco v. ibm famous inventions developments ibm include automated teller machine atm dynamic random access memory dram electronic keypunch financial swap floppy disk hard disk drive magnetic stripe card relational database risc sabre airline reservation system sql universal product code upc bar code virtual machine additionally 1990 company scientists used scanning tunneling microscope arrange 35 individual xenon atoms spell company acronym marking first structure assembled one atom time major part ibm research generation patents since first patent traffic signaling device ibm one world prolific patent sources 2018 company holds record patents generated business marking 25 consecutive years achievement five ibmers received nobel prize leo esaki thomas j. watson research center yorktown heights n.y. 1973 work semiconductors gerd binnig heinrich rohrer zurich research center 1986 scanning tunneling microscope georg bednorz alex müller also zurich 1987 research superconductivity several ibmers also turing award including first female recipient frances e. allen current research includes collaboration university michigan see computers act academic advisor undergraduate computer science engineering students university partnership combining cloud internet things iot platforms make interoperable provide developers easier tools company also involved research advanced algorithms machine learning decision-making processes end company recently released analysis tool algorithms make decisions scanning biases automated decision-making ibm nicknamed big blue part due blue logo color scheme also partially since ibm de facto dress code white shirts blue suits company logo undergone several changes years current 8-bar logo designed 1972 graphic designer paul rand general replacement 13-bar logo since period photocopiers render large areas well aside logo ibm used helvetica corporate typeface 50 years replaced 2017 custom-designed ibm plex ibm valuable brand result 100 years operations marketing campaigns since 1996 ibm exclusive technology partner masters tournament one four major championships professional golf ibm creating first masters.org 1996 first course cam 1998 first iphone app live streaming 2009 first-ever live 4k ultra high definition feed united states major sporting event 2016 result ibm ceo ginni rometty became third female member master governing body augusta national golf club ibm also major sponsor professional tennis engagements u.s. open wimbledon australian open french open company also sponsored olympic games 1960–2000 national football league 2003–2012 2012 ibm brand valued 75.5 billion ranked interbrand second-best brand worldwide year also ranked top company leaders fortune number two green company u.s. newsweek second-most respected company barron fifth-most admired company fortune 18th-most innovative company fast company number one technology consulting number two outsourcing vault 2015 forbes ranked ibm fifth-most valuable brand january 1969 last day johnson administration united states department justice antitrust division filed suit ibm alleging company engaged monopolistic business practices talks ibm would agree settlement consent decree two sides unable come terms case went trial 1975 legal matter justice department estimated would take 60 days three years millions pages evidence justice department decided drop suit new york times article states ibm never publicly disclosed much spent defending suit estimated tens millions dollars ibm one largest workforces world employees big blue referred ibmers company among first corporations provide group life insurance 1934 survivor benefits 1935 training women 1935 paid vacations 1937 training disabled people 1942 ibm hired first black salesperson 1946 1952 ceo thomas j. watson jr. published company first written equal opportunity policy letter one year u.s. supreme court decision brown vs. board education 11 years civil rights act 1964 human rights campaign rated ibm 100 index gay-friendliness every year since 2003 ibm providing same-sex partners employees health benefits anti-discrimination clause additionally 2005 ibm became first major company world commit formally use genetic information employment decisions 2017 ibm named working mother 100 best companies list 32nd consecutive year ibm several leadership development recognition programs recognize employee potential achievements early-career high potential employees ibm sponsors leadership development programs discipline e.g. general management gmldp human resources hrldp finance fldp year company also selects 500 ibmers ibm corporate service corps csc described corporate equivalent peace corps gives top employees month humanitarian work abroad certain interns ibm also program called extreme blue partners top business technical students develop high-value technology compete present business case company ceo internship end company also various designations exceptional individual contributors senior technical staff member stsm research staff member rsm distinguished engineer de distinguished designer dd prolific inventors also achieve patent plateaus earn designation master inventor company prestigious designation ibm fellow since 1963 company names handful fellows year based technical achievement programs recognize years service quarter century club established 1924 sellers eligible join hundred percent club composed ibm salesmen meet quotas convened atlantic city new jersey year company also selects 1,000 ibmers annually award best ibm award includes all-expenses paid trip awards ceremony exotic location ibm culture evolved significantly century operations early days dark gray suit white shirt sincere tie constituted public uniform ibm employees ibm management transformation 1990s ceo louis v. gerstner jr. relaxed codes normalizing dress behavior ibm employees company culture also given different plays company acronym ibm saying stands 've moved due relocations layoffs others saying stands 'm pursuant prevalent work-from-anywhere norm others saying stands 'm mentored due company open door policy encouragement mentoring levels terms labor relations company traditionally resisted labor union organizing although unions represent ibm workers outside united states japan ibm employees also american football team complete pro stadium cheerleaders televised games competing japanese x-league big blue 2015 ibm started giving employees option choosing either pc mac primary work device resulting ibm becoming world largest mac shop 2016 ibm eliminated forced rankings changed annual performance review system focus frequent feedback coaching skills development many ibmers also achieved notability outside work leaving ibm business former ibm employees include apple inc. ceo tim cook former eds ceo politician ross perot microsoft chairman john w. thompson sap co-founder hasso plattner gartner founder gideon gartner advanced micro devices amd ceo lisa su former citizens financial group ceo ellen alemany former yahoo chairman alfred amoroso former ceo c. michael armstrong former xerox corporation ceos david t. kearns g. richard thoman former fair isaac corporation ceo mark n. greene citrix systems co-founder ed iacobucci asos.com chairman brian mcbride former lenovo ceo steve ward former teradata ceo kenneth simonds government alumna patricia roberts harris served united states secretary housing urban development first african american woman serve united states cabinet samuel k. skinner served u.s. secretary transportation white house chief staff alumni also include u.s senators mack mattingly thom tillis wisconsin governor scott walker former u.s ambassadors vincent obsitnik slovakia arthur k. watson france thomas watson jr. soviet union former u.s representatives todd akin glenn andrews robert garcia katherine harris amo houghton jim ross lightfoot thomas j. manton donald w. riegle jr. ed zschau others nasa astronaut michael j. massimino canadian astronaut governor-general julie payette harvey mudd college president maria klawe western governors university president emeritus robert mendenhall former university kentucky president lee t. todd jr. nfl referee bill carollo former rangers f.c chairman john mcclelland recipient nobel prize literature j. m. coetzee thomas watson jr. also served 11th national president boy scouts america company 14 member board directors responsible overall corporate management includes ceos american express ford motor company boeing dow chemical johnson johnson cemex well president rensselaer polytechnic institute 2011 ibm became first technology company warren buffett holding company berkshire hathaway invested initially bought 64 million shares costing 10.5 billion dollars years increased ibm holdings however reduced 94.5 2.05 million shares end 2017 may 2018 completely ibm
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Distributed computing architecture
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new world rom new world rom computers macintosh models use macintosh toolbox rom logic board due mac os x requiring availability toolbox allowed rom sizes shrink dramatically typically facilitated use flash memory system firmware instead expensive less flexible mask rom previous macs used facility loading toolbox startup device however made available allowing use mac os 8 mac os 9 new world machines new world architecture developed macintosh network computer unrealized project eventually contributed several key technologies first-generation imac powerpc macs imac ibook blue white power mac g3 bronze keyboard lombard powerbook g3 forward new world rom machines previous models including beige power mac g3 beige platinum macs old world rom machines intel based macs incapable running mac os 9 machines efi used instead open firmware new world old world machines based new world rom macs first macs direct usage open firmware subsystem encouraged previous pci power macs used open firmware booting implementation complete machines expected probe pci devices immediately hand control mac os rom versions 1.0.5 2.x several serious bugs well missing functionality able load files hfs partition tftp server apple also set default input output devices ttya modem port beige macs made difficult normal users get open firmware necessary either hook terminal change open firmware settings inside mac os using tool boot variables apple system disk new world rom introduced much-improved version open firmware interpreter version 3.0 added many missing features fixed bugs earlier versions capability run chrp boot scripts toolbox rom embedded inside chrp script system folder called mac os rom along short loader stub copy happy mac icon suitable display open firmware rom loaded disk mac boot sequence continued usual open firmware could also run binary boot loader version 3.0 added support elf objects well xcoff files versions 1.0.5 2.0 supported also version 3.0 well last releases version 2.x starting powerbook 3400 officially supported direct access open firmware command prompt console setting auto-boot variable false mac os holding command-option-o-f boot one major difference old world rom macs new world rom macs least classic mac os gestalt selector machine type longer usable new world rom macs use mach id 406 decimal actual machine id encoded model compatible properties root node open firmware device tree new world rom also sets compatible property root node macrisc2 machines boot classic mac os using mac os rom macrisc3 machines boot mac os x another unix-like system somewhat easier boot non-mac-os operating system new world system indeed openbsd bootloader works new world system simplest way distinguish new world rom mac factory built-in usb port old world rom mac usb port factory equipment instead used adb keyboard mouse mini-din-8 modem printer serial ports peripherals also new world rom macs generally built-in floppy drive
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Operating systems
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bandit kings ancient china bandit kings ancient china also known japan turn-based strategy video game developed published koei released 1989 ms-dos amiga macintosh 1990 nintendo entertainment system 1996 koei issued remake japanese sega saturn sony playstation featuring vastly improved graphics new arrangements original songs based great classical novel water margin game takes place ancient china reign emperor huizong song dynasty bandit kings ancient china—a band ten bandits—engage war china minister war gao qiu evil person unlimited power objective game build sustain command army troops capture gao qiu jurchen invasion january 1127 players hold certain attributes strength dexterity wisdom players must also deal situations taxes care troops maintenance replacement weapons equipment forces nature troop unrest desertion battlefields take place hexagonal grids players move armies across various terrain order strategically engage defeat enemy army troops capability fighting either melee weapons bows arrows magic dueling swords player defeats enemy army option recruiting imprisoning exiling executing captured enemy troops attacker 30 days win castles defeat deployed enemy commanders automatically defeated game ends defeat player game calendar hit january 1127 game map shows empire composed 48 prefectures prefecture may invaded adjacent territory exception imperial capital kaifeng player must built sufficient popularity gain attention emperor confer imperial decree permitting player march capital reviewing nes version bandit kings ancient china nintendo power suggested players might find game pace slow compared action-oriented games others would enjoy game depth involvement attention detail compute magazine praised game one complete entertaining role-playing simulations available gave honorable mention war/strategy category 1991 compute choice awards reviewer austin american-statesman suggested game depth overwhelming calling game richest complex role-playing game ever published saying trouble figuring ... supposed pc magazine reviewed game positively concluding bandit kings ancient china addictive game brought alive mixture computer-driven personalities romance departed culture large battery options unpredictability game play computer gaming world gave game three five stars 1990 two stars 1993 amiga version received positive reviews amiga magazines game reviewed 1994 dragon 211 jay dee eye monitor column reviewers gave game 3½ 5 stars computer gaming world named bandit kings ancient china antagonist gao qiu twelfth memorable game villain
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Computer architecture
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distributed lock manager operating systems use lock managers organise serialise access resources distributed lock manager dlm runs every machine cluster identical copy cluster-wide lock database way dlm provides software applications distributed across cluster multiple machines means synchronize accesses shared resources dlms used foundation several successful clustered file systems machines cluster use storage via unified file system significant advantages performance availability main performance benefit comes solving problem disk cache coherency participating computers dlm used file locking also coordination disk access vmscluster first clustering system come widespread use relies openvms dlm way dec vms virtual memory system first widely available operating system implement dlm became available version 4 although user interface single-processor lock manager first implemented version 3 dlm uses generalized concept resource entity shared access must controlled relate file record area shared memory anything else application designer chooses hierarchy resources may defined number levels locking implemented instance hypothetical database might define resource hierarchy follows process acquire locks database whole particular parts database lock must obtained parent resource subordinate resource locked process running within vmscluster may obtain lock resource six lock modes granted determine level exclusivity granted possible convert lock higher lower level lock mode processes unlocked resource system information resource destroyed following truth table shows compatibility lock mode others process obtain lock resource enqueueing lock request similar qio technique used perform i/o enqueue lock request either complete synchronously case process waits lock granted asynchronously case ast occurs lock obtained also possible establish blocking ast triggered process obtained lock preventing access resource another process original process optionally take action allow access e.g demoting releasing lock lock value block associated resource read process obtained lock resource null lock updated process obtained protected update exclusive lock used hold information resource application designer chooses typical use hold version number resource time associated entity e.g database record updated holder lock increments lock value block another process wishes read resource obtains appropriate lock compares current lock value value last time process locked resource value process knows associated entity updated since last time read therefore unnecessary read hence technique used implement various types cache database similar application one processes obtained locks resources possible produce situation preventing another obtaining lock none proceed known deadlock e. w. dijkstra originally called deadly embrace simple example process 1 obtained exclusive lock resource process 2 obtained exclusive lock resource b process 1 tries lock resource b wait process 2 release process 2 tries lock resource processes wait forever openvms dlm periodically checks deadlock situations example second lock enqueue request one processes would return deadlock status would process take action resolve deadlock—in case releasing first lock obtained red hat oracle developed clustering software linux ocfs2 oracle cluster file system added official linux kernel version 2.6.16 january 2006 alpha-quality code warning ocfs2 removed 2.6.19 red hat cluster software including dlm gfs2 officially added linux kernel version 2.6.19 november 2006 systems use dlm modeled venerable vms dlm oracle dlm simpler api core function codice_1 eight parameters whereas vms service red hat dlm_lock 11 dlm implementations include following
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Distributed computing architecture
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content guru content guru cloud communications provider based bracknell uk provides services 30 countries storm platform direct partners vodafone kpn signed five-year renewal june 2017 deliver storm services across benelux region april 2016 content guru received queen award innovation storm contact multi-channel cloud contact centre solution contact used organisations across multiple sectors connect customers information devices choose notable clients including national health service serco sodexo travisperkins recognition solution deployed national health service nhs content guru several awards including vertical application solution year europa awards 2019 best use cloud services uk industry awards 2015 2016 best class digital transformation uk cloud awards 2017 best public sector digital project computing technology leaders award 2017 content guru founded 2005 sean martin taylor sister company hardware manufacturer software developer redwood technologies 2010 company storm platform used comres behalf itv news provide live audience polling first televised election leaders debate build-up uk 2010 general election 2013 content guru co-founded berkshire community foundation bcf business philanthropy club bpc enables businesses berkshire provide funding grassroots organisations projects local communities content guru sponsor along parent company redwood technologies group lead organiser pride bracknell forest awards since 2016 company announced would delivering services united states world largest contact centre market march 2017 later year august content guru vodafone handled 16,000 student enquiries ucas uk higher education applications service.. 2015 2016 2017 content guru positioned challenger gartner magic quadrant ccaas contact center service western europe january 2018 minority stake content guru sister company redwood technologies group sold scottish equity partners £25 million cash deal content guru announced partnership rakuten communications february 2018 deliver cloud contact centre services japan company came fire role manchester arena bombing may 2017 storm telecommunications platform failed operate resulted affected attack able contact police emergency services vodafone subcontracted services content guru providing national mutual aid telephony system however tried use found inability amend recorded message technical difficulties server suggests inadequate level knowledge expertise within vodafone sub-contractor content guru vodafone content guru continue partnership vodafone marketing content guru platform brand vodafone storm
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Distributed computing architecture
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lustre file system lustre type parallel distributed file system generally used large-scale cluster computing name lustre portmanteau word derived linux cluster lustre file system software available gnu general public license version 2 provides high performance file systems computer clusters ranging size small workgroup clusters large-scale multi-site clusters lustre file systems high performance capabilities open licensing often used supercomputers since june 2005 consistently used least half top ten 60 top 100 fastest supercomputers world including world 2 3 ranked top500 supercomputers 2014 titan sequoia lustre file systems scalable part multiple computer clusters tens thousands client nodes tens petabytes pb storage hundreds servers terabyte per second tb/s aggregate i/o throughput makes lustre file systems popular choice businesses large data centers including industries meteorology simulation oil gas life science rich media finance i/o performance lustre widespread impact applications attracted broad attention lustre file system architecture started research project 1999 peter j. braam staff carnegie mellon university cmu time braam went found company cluster file systems 2001 starting work intermezzo file system coda project cmu lustre developed accelerated strategic computing initiative path forward project funded united states department energy included hewlett-packard intel september 2007 sun microsystems acquired assets cluster file systems inc. including intellectual property sun included lustre high-performance computing hardware offerings intent bring lustre technologies sun zfs file system solaris operating system november 2008 braam left sun microsystems eric barton andreas dilger took control project 2010 oracle corporation way acquisition sun began manage release lustre december 2010 oracle announced would cease lustre 2.x development place lustre 1.8 maintenance-only support creating uncertainty around future development file system following announcement several new organizations sprang provide support development open community development model including whamcloud open scalable file systems inc. opensfs european open file systems eofs others end 2010 lustre developers left oracle braam several associates joined hardware-oriented xyratex acquired assets clusterstor barton dilger others formed software startup whamcloud continued work lustre august 2011 opensfs awarded contract lustre feature development whamcloud contract covered completion features including improved single server metadata performance scaling allows lustre better take advantage many-core metadata server online lustre distributed filesystem checking lfsck allows verification distributed filesystem state data metadata servers filesystem mounted use distributed namespace environment dne formerly clustered metadata cmd allows lustre metadata distributed across multiple servers development also continued zfs-based back-end object storage lawrence livermore national laboratory features lustre 2.2 2.4 community release roadmap november 2011 separate contract awarded whamcloud maintenance lustre 2.x source code ensure lustre code would receive sufficient testing bug fixing new features developed july 2012 whamcloud acquired intel whamcloud fastforward doe contract extend lustre exascale computing systems 2018 timeframe opensfs transitioned contracts lustre development intel february 2013 xyratex ltd. announced acquired original lustre trademark logo website associated intellectual property oracle june 2013 intel began expanding lustre usage beyond traditional hpc within hadoop 2013 whole opensfs announced request proposals rfp cover lustre feature development parallel file system tools addressing lustre technical debt parallel file system incubators opensfs also established lustre community portal technical site provides collection information documentation one area reference guidance support lustre open source community april 8 2014 ken claffey announced xyratex/seagate donating domain back user community completed march 2015 june 2018 lustre team assets acquired intel ddn ddn organized new acquisition independent division reviving whamcloud name new division lustre file system first installed production use march 2003 mcr linux cluster lawrence livermore national laboratory one largest supercomputers time lustre 1.0.0 released december 2003 provided basic lustre filesystem functionality including server failover recovery lustre 1.2.0 released march 2004 worked linux kernel 2.6 size glimpse feature avoid lock revocation files undergoing write client side data write-back cache accounting grant lustre 1.4.0 released november 2004 provided protocol compatibility versions could use infiniband networks could exploit extents/mballoc ldiskfs on-disk filesystem lustre 1.6.0 released april 2007 allowed mount configuration “ mountconf ” allowing servers configured mkfs mount allowed dynamic addition object storage targets osts enabled lustre distributed lock manager ldlm scalability symmetric multiprocessing smp servers provided free space management object allocations lustre 1.8.0 released may 2009 provided oss read cache improved recovery face multiple failures added basic heterogeneous storage management via ost pools adaptive network timeouts version-based recovery transition release interoperable lustre 1.6 lustre 2.0 lustre 2.0 released august 2010 based significant internally restructured code prepare major architectural advancements lustre 2.x clients interoperate 1.8 earlier servers however lustre 1.8.6 later clients interoperate lustre 2.0 later servers metadata target mdt ost on-disk format 1.8 upgraded 2.0 later without need reformat filesystem lustre 2.1 released september 2011 community-wide initiative response oracle suspending development lustre 2.x releases added ability run servers red hat linux 6 increased maximum ext4-based ost size 24 tb 128 tb well number performance stability improvements lustre 2.1 servers remained inter-operable 1.8.6 later clients lustre 2.2 released march 2012 focused providing metadata performance improvements new features added parallel directory operations allowing multiple clients traverse modify single large directory concurrently faster recovery server failures increased stripe counts single file across 2000 osts improved single-client directory traversal performance lustre 2.3 released october 2012 continued improve metadata server code remove internal locking bottlenecks nodes many cpu cores 16 object store added preliminary ability use zfs backing file system lustre file system check lfsck feature verify repair mds object index oi file system use file-level backup/restore case mds corruption server-side io statistics enhanced allow integration batch job schedulers slurm track per-job statistics client-side software updated work linux kernels version 3.0 lustre 2.4 released may 2013 added considerable number major features many funded directly opensfs distributed namespace environment dne allows horizontal metadata capacity performance scaling 2.4 clients allowing subdirectory trees single namespace located separate mdts zfs used backing filesystem mdt ost storage lfsck feature added ability scan verify internal consistency mdt fid linkea attributes network request scheduler nrs adds policies optimize client request processing disk ordering fairness clients optionally send bulk rpcs 4 mb size client-side software updated work linux kernels version 3.6 still interoperable 1.8 clients lustre 2.5 released october 2013 added highly anticipated feature hierarchical storage management hsm core requirement enterprise environments hsm allows customers easily implement tiered storage solutions operational environment release current opensfs-designated maintenance release branch lustre recent maintenance version 2.5.3 released september 2014 lustre 2.6 released july 2014 modest release feature wise adding lfsck functionality local consistency checks ost well consistency checks mdt ost objects nrs token bucket filter tbf policy added single-client io performance improved previous releases release also added preview dne striped directories allowing single large directories stored multiple mdts improve performance scalability lustre 2.7 released march 2015 added lfsck functionality verify dne consistency remote striped directories multiple mdts dynamic lnet config adds ability configure modify lnet network interfaces routes routers runtime new evaluation feature added uid/gid mapping clients different administrative domains along improvements dne striped directory functionality lustre 2.8 released march 2016 finished dne striped directory feature including support migrating directories mdts cross-mdt hard link rename well included improved support security-enhanced linux selinux client kerberos authentication rpc encryption network performance improvements lfsck lustre 2.9 released december 2016 included number features related security performance shared secret key security flavour uses gssapi mechanism kerberos provide client server node authentication rpc message integrity security encryption nodemap feature allows categorizing client nodes groups mapping uid/gid clients allowing remotely administered clients transparently use shared filesystem without single set uid/gids client nodes subdirectory mount feature allows clients mount subset filesystem namespace mds release also added support 16mib rpcs efficient i/o submission disk added codice_1 interface allow clients provide i/o hints servers prefetch file data server cache flush file data server cache improved support specifying filesystem-wide default ost pools improved inheritance ost pools conjunction file layout parameters lustre 2.10 released july 2017 number significant improvements lnet multi-rail lmr feature allows bonding multiple network interfaces infiniband omni-path and/or ethernet client server increase aggregate i/o bandwidth file layouts constructed multiple components based file offset allow different parameters stripe count ost pool etc determined based file size nrs token bucket filter tbf server-side scheduler implemented new rule types including rpc-type scheduling ability specify multiple parameters jobid nid rule matching tools managing zfs snapshots lustre filesystems added simplify creation mounting management mdt ost zfs snapshots separate lustre mountpoints lustre 2.11 released april 2018 contains two significant new features several smaller features file level redundancy flr feature expands 2.10 pfl implementation adding ability specify mirrored file layouts improved availability case storage server failure and/or improved performance highly concurrent reads data-on-mdt dom feature allows small mib files stored mdt leverage typical flash-based raid-10 storage lower latency reduced io contention instead typical hdd raid-6 storage used osts well lnet dynamic discovery feature allows auto-configuration lnet multi-rail peers share lnet network ldlm lock ahead feature allows appropriately modified applications libraries pre-fetch dlm extent locks osts files application knows predicts file extent modified near future reduce lock contention multiple clients writing file lustre 2.12 released december 21 2018 focused improving lustre usability stability improvements performance functionality flr dom features added lustre 2.11 well smaller changes nrs tbf hsm jobstats added lnet network health allow lnet multi-rail feature lustre 2.10 better handle network faults node multiple network interfaces lazy size mdt lsom feature allows storing estimate file size mdt use policy engines filesystem scanners management tools efficiently make decisions files without fully accurate file sizes blocks count without query osts information release also added ability manually restripe existing directory across multiple mdts allow migration directories large numbers files use capacity performance several mds nodes lustre rpc data checksum added scsi t10-pi integrated data checksums client kernel block layer scsi host adapter t10-enabled hard drives lustre file system three major functional units mdt ost client may node usually testing purposes typical production installations devices separate nodes communicating network mdt ost may part single filesystem though possible multiple mdts osts single node part different filesystems lustre network lnet layer use several types network interconnects including native infiniband verbs omni-path roce iwarp via ofed tcp/ip ethernet proprietary network technologies cray gemini interconnect lustre 2.3 earlier myrinet quadrics cray seastar rapidarray networks also supported network drivers deprecated networks longer commercially available support removed completely lustre 2.8 lustre take advantage remote direct memory access rdma transfers available improve throughput reduce cpu usage storage used mdt ost backing filesystems normally provided hardware raid devices though work block devices since lustre 2.4 mdt ost also use zfs backing filesystem addition ext4 allowing effectively use jbod storage instead hardware raid devices lustre oss mds servers read write modify data format imposed backing filesystem return data clients allows lustre take advantage improvements features underlying filesystem compression data checksums zfs clients direct access underlying storage ensures malfunctioning malicious client corrupt filesystem structure ost dedicated filesystem exports interface byte ranges file objects read/write operations extent locks protect data consistency mdt dedicated filesystem stores inodes directories posix extended file attributes controls file access permissions/acls tells clients layout object make regular file mdts osts currently use either enhanced version ext4 called ldiskfs zfs/dmu back-end data storage store files/objects using open source zfs-on-linux port client mounts lustre filesystem locally vfs driver linux kernel connects client server upon initial mount client provided file identifier fid root directory mountpoint client accesses file performs filename lookup mds mds filename lookup complete user client permission access and/or create file either layout existing file returned client new file created behalf client requested read write operations client interprets file layout logical object volume lov layer maps file logical offset size one objects client locks file range operated executes one parallel read write operations directly oss nodes hold data objects approach bottlenecks client-to-oss communications eliminated total bandwidth available clients read write data scales almost linearly number osts filesystem initial lookup file layout mds normally involved file io operations since block allocation data io managed internally ost clients directly modify objects data ost filesystems instead delegate task oss nodes approach ensures scalability large-scale clusters supercomputers well improved security reliability contrast shared block-based filesystems gpfs ocfs allow direct access underlying storage clients filesystem requires large back-end san attached clients increases risk filesystem corruption misbehaving/defective clients typical lustre installation linux client lustre filesystem driver module loaded kernel filesystem mounted like local network filesystem client applications see single unified filesystem even though may composed tens thousands individual servers mdt/ost filesystems massively parallel processor mpp installations computational processors access lustre file system redirecting i/o requests dedicated i/o node configured lustre client approach used blue gene installation lawrence livermore national laboratory another approach used early years lustre liblustre library cray xt3 using catamount operating system systems sandia red storm provided userspace applications direct filesystem access liblustre user-level library allows computational processors mount use lustre file system client using liblustre computational processors could access lustre file system even service node job launched linux client liblustre allowed data movement directly application space lustre osss without requiring intervening data copy kernel thus providing access computational processors lustre file system directly constrained operating environment liblustre functionality deleted lustre 2.7.0 disabled since lustre 2.6.0 untested since lustre 2.3.0 linux kernel version 4.18 incomplete port lustre client removed kernel staging area order speed development porting newer kernels out-of-tree lustre client server still available rhel sles ubuntu distro kernels well vanilla kernels traditional unix disk file system inode data structure contains basic information file data contained file stored lustre file system also uses inodes inodes mdts point one ost objects associated file rather data blocks objects implemented files osts client opens file file open operation transfers set object identifiers layout mds client client directly interact oss node object stored allows client perform i/o parallel across ost objects file without communication mds one ost object associated mdt inode object contains data lustre file one object associated file data file striped chunks round-robin manner across ost objects similar raid 0 striping file multiple ost objects provides significant performance benefits need high bandwidth access single large file striping used maximum file size limited size single target capacity aggregate i/o bandwidth scale number osts file striped also since locking object managed independently ost adding stripes one per ost scales file i/o locking capacity file proportionately file created filesystem may specify different layout parameters stripe count number ost objects making file stripe size unit data stored ost moving next ost selection performance capacity tuned optimally file many application threads reading writing separate files parallel optimal single stripe per file since application providing parallelism many threads reading writing single large file concurrently optimal one stripe ost maximize performance capacity file lustre 2.10 release ability specify composite layouts added allow files different layout parameters different regions file progressive file layout pfl feature uses composite layouts improve file io performance wider range workloads well simplify usage administration example small pfl file single stripe low access overhead larger files many stripes high aggregate bandwidth better ost load balancing composite layouts enhanced 2.11 release file level redundancy flr feature allows file multiple overlapping layouts file providing raid 0+1 redundancy files well improved read performance lustre 2.11 release also added data-on-metadata dom feature allows first component pfl file stored directly mdt inode reduces overhead accessing small files terms space usage ost object needed well network usage fewer rpcs needed access data dom also improves performance small files mdt ssd-based osts disk-based client initially mounts filesystem provided 128-bit lustre file identifier fid composed 64-bit sequence number 32-bit object id 32-bit version root directory mountpoint filename lookup client performs lookup pathname component mapping parent directory fid sequence number specific mdt via fid location database fldb lookup mds managing mdt using parent fid filename mds return fid requested pathname component along dlm lock mdt last parent directory determined directory operations non-striped directories take place exclusively mdt avoiding contention mdts dne striped directories per-directory layout stored parent directory provides hash function list mdt directory fids across directory distributed logical metadata volume lmv client hashes filename maps specific mdt directory shard handle operations file identical manner non-striped directory readdir operations entries directory shard returned client sorted local mdt directory hash order client performs merge sort interleave filenames hash order single 64-bit cookie used determine current offset within directory lustre distributed lock manager ldlm implemented openvms style protects integrity file data metadata access modification lustre file completely cache coherent among clients metadata locks managed mdt stores inode file using fid resource name metadata locks split separate bits protect lookup file file owner group permission mode access control list acl state inode directory size directory contents link count timestamps layout file striping since lustre 2.4 extended attributes xattrs since lustre 2.5 client fetch multiple metadata lock bits single inode single rpc request currently ever granted read lock inode mds manages modifications inode order avoid lock resource contention currently node gets write locks inodes file data locks managed ost object file striped using byte-range extent locks clients granted overlapping read extent locks part file allowing multiple concurrent readers file and/or non-overlapping write extent locks independent regions file allows many lustre clients access single file concurrently read write avoiding bottlenecks file i/o practice linux clients manage data cache units pages clients request locks always integer multiple page size 4096 bytes clients client requesting extent lock ost may grant lock larger extent originally requested order reduce number lock requests client makes actual size granted lock depends several factors including number currently granted locks object whether conflicting write locks requested lock extent number pending lock requests object granted lock never smaller originally requested extent ost extent locks use lustre fid object resource name lock since number extent lock servers scales number osts filesystem also scales aggregate locking performance filesystem single file striped multiple osts communication lustre clients servers implemented using lustre networking lnet originally based sandia portals network programming application programming interface disk storage connected lustre mds oss server nodes using direct attached storage sas fc iscsi traditional storage area network san technologies independent client-to-server network lnet use many commonly used network types infiniband tcp commonly ethernet networks allows simultaneous availability across multiple network types routing remote direct memory access rdma used data metadata transfer nodes provided underlying networks infiniband roce iwarp omni-path high availability recovery features enable transparent recovery conjunction failover servers since lustre 2.10 lnet multi-rail mr feature allows link aggregation two network interfaces client server improve bandwidth lnet interface types need network type 2.12 multi-rail enhanced improve fault tolerance multiple network interfaces available peers lnet provides end-to-end throughput gigabit ethernet networks excess 100 mb/s throughput 3 gb/s using infiniband quad data rate qdr links throughput 1 gb/s across 10 gigabit ethernet interfaces lustre file system high availability features include robust failover recovery mechanism making server failures reboots transparent version interoperability successive minor versions lustre software enables server upgraded taking offline failing standby server performing upgrade restarting active jobs continue run experiencing delay backup server takes storage lustre mdses configured active/passive pair one active/active mds pairs dne osses typically deployed active/active configuration provides redundancy without extra overhead often standby mds one filesystem mgs and/or monitoring node active mds another file system nodes idle cluster lustre provides capability multiple storage tiers within single filesystem namespace allows traditional hsm functionality copy archive files primary filesystem secondary archive storage tier archive tier typically tape-based system often fronted disk cache file archived released main filesystem leaving stub references archive copy released file opened coordinator blocks open sends restore request copytool completes open copytool completed restoring file addition external storage tiering possible multiple storage tiers within single filesystem namespace osts different types e.g hdd ssd declared named storage pools ost pools selected specifying file layouts different pools used within single pfl file layout files migrated storage tiers either manually control policy engine since lustre 2.11 also possible mirror file different ost pools flr file layout example pre-stage files flash computing job hsm includes additional lustre components manage interface primary filesystem archive hsm also defines new states files including lustre used many top500 supercomputers large multi-cluster sites six top 10 60 top 100 supercomputers use lustre file systems include k computer riken advanced institute computational science tianhe-1a national supercomputing center tianjin china jaguar titan oak ridge national laboratory ornl blue waters university illinois sequoia blue gene/l lawrence livermore national laboratory llnl also large lustre filesystems national energy research scientific computing center pacific northwest national laboratory texas advanced computing center brazilian national laboratory scientific computing nasa north america asia tokyo institute technology europe cea many others commercial technical support lustre often bundled along computing system storage hardware sold vendor vendors include cray dell hewlett-packard hp storageworks scalable file share circa 2004 2008 groupe bull silicon graphics international fujitsu vendors selling storage hardware bundled lustre support include hitachi data systems datadirect networks ddn netapp seagate technology others also possible get software-only support lustre file systems vendors including whamcloud amazon web services offers amazon fsx lustre fully managed service making easy launch run high-performance file systems cost effectively cloud
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Computer file systems
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identity interrogation identity interrogation method authentication identity proofing involves posing one knowledge-based authentication questions individual identity interrogation questions mother ’ maiden name last four digits social security number questioning process requires individuals reveal personally identifiable information pii order prove identity method businesses use prevent identity theft impersonation customers identity interrogation primarily employed remote in-person interactions teller bank many interactions require user authentication internet telephone employ identity interrogation substitute stronger authentication methods physical ownership authentication i.e presenting driver license bankcard biometrics i.e fingerprint facial recognition available mainly in-person interactions identity interrogation used assist risk management account security legal regulatory compliance remote interactions addition technique developed assist prevention identity fraud illegal use another person identity commit fraud criminal activities identity interrogation methods commonly used governments organizations companies banks financial intermediaries credit card companies internet providers telecommunications companies insurance providers others
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Computer security
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hidden file hidden directory computing hidden folder sometimes hidden directory hidden file folder file filesystem utilities display default showing directory listing commonly used storing user preferences preserving state utility frequently created implicitly using various utilities security mechanism access restricted usually intent simply clutter display contents directory listing files user directly create unix-like operating systems file folder starts dot character example /home/user/.config commonly called dot file dotfile treated hidden – codice_1 command display unless codice_2 flag codice_3 used command-line shells wildcards match files whose names start codice_4 unless wildcard starts explicit codice_4 convention arose using dotfiles user home directory store per-user configuration informational text early uses well-known dotfiles codice_6 codice_7 codice_8 configuration files bourne shell c shell shells compatible codice_9 codice_10 used codice_11 codice_12 commands many applications bash desktop environments gnome store per-user configuration way unix/linux freedesktop.org xdg base directory specification aims migrate user config files individual dotfiles codice_13 non-hidden files hidden directory codice_14 android operating system uses empty codice_15 files tell smartphone apps display include contents folder prevents digital photos digital music files shown picture galleries played mp3 player apps useful prevent downloaded voicemail files playing songs playlist keep personal photos private still allowing folders shared person friends family colleagues codice_15 file effect filesystem even operating system instead depends entirely individual app respect presence different files gnome desktop environment well programs written using glib filenames listed file named codice_17 directory also excluded display gnome file manager keyboard shortcut enables display kinds hidden files addition dotfile behaviour files invisible attribute hidden finder although codice_1 invisible attribute set cleared using codice_19 command example invoking codice_20 hide file jimbo starting mac os x snow leopard codice_21 command also used example codice_22 hide file jimbo dos systems file directory entries include hidden file attribute manipulated using attrib command use command line command codice_23 display files attribute hidden windows explorer content directory hidden appending pre-defined clsid end folder name directory still visible content becomes one windows special folders however real content directory still seen using cli command codice_24
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Computer file systems
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glite glite pronounced gee-lite middleware computer software project grid computing used cern lhc experiments scientific domains implemented collaborative efforts 80 people 12 different academic industrial research centers europe glite provides framework building applications tapping distributed computing storage resources across internet glite services adopted 250 computing centres used 15000 researchers europe around world prototyping phases 2004 2005 convergence lhc computing grid lcg-2 distribution reached may 2006 glite 3.0 released became official middle-ware enabling grids e-science egee project ended 2010 development glite middle-ware taken european middleware initiative maintained part emi software stack distributed computing infrastructure built egee supported european grid infrastructure runs grid middle-ware produced european middleware initiative many components came glite middle-ware glite user community grouped virtual organisations vos user must join vo supported infrastructure running glite authenticated authorized using grid resources grid security infrastructure gsi wlcg/egee enables secure authentication communication open network gsi based public key encryption x.509 certificates secure sockets layer ssl communication protocol extensions single sign-on delegation authenticate him/herself user needs digital x.509 certificate issued certification authority ca trusted infrastructure running middle-ware authorization user specific grid resource done two different ways first simpler relies grid-mapfile mechanism second way relies virtual organisation membership service voms lcas/lcmaps mechanism allow detailed definition user privileges access point glite grid user interface ui machine users personal account user certificate installed ui user authenticated authorized use wlcg/egee resources access functionalities offered information workload data management systems provides cli tools perform basic grid operations computing element ce grid terminology set computing resources localized site i.e cluster computing farm ce includes grid gate gg acts generic interface cluster local resource management system lrms sometimes called batch system cluster collection worker nodes wns nodes jobs run two ce implementations glite 3.1 lcg ce developed edg used lcg-22 glite ce developed egee sites choose install provide types gg responsible accepting jobs dispatching execution wns via lrms glite 3.1 supported lrms types openpbs/pbspro platform lsf maui/torque bqs condor sun grid engine storage element se provides uniform access data storage resources storage element may control simple disk servers large disk arrays tape-based mass storage systems mss wlcg/egee sites provide least one se storage elements support different data access protocols interfaces simply speaking gsiftp gsi-secure ftp protocol whole-file transfers local remote file access performed using rfio gsidcap storage resources managed storage resource manager srm middle-ware service providing capabilities like transparent file migration disk tape file pinning space reservation etc however different ses may support different versions srm protocol capabilities vary number srm implementations use varying capabilities disk pool manager dpm used fairly small ses disk-based storage castor designed manage large-scale mss front-end disks back-end tape storage dcache targeted mss large-scale disk array storage systems srm implementations development srm protocol specification also evolving classic ses srm interface provide simple disk-based storage model process phased information service provides information wlcg/egee grid resources status information essential operation whole grid via resources discovered published information also used monitoring accounting purposes much data published conforms glue schema defines common conceptual data model used grid resource monitoring discovery information system used glite 3.1 inherits main concepts globus monitoring discovery service mds however gris giis mds replaced berkeley database information index essentially openldap server updated external process purpose workload management system wms accept user jobs assign appropriate computing element record status retrieve output resource broker rb machine wms services run jobs submitted described using job description language jdl specifies example executable run parameters files moved worker node job run input grid files needed requirements ce worker node choice ce job sent made process called match-making first selects among available ces fulfill requirements expressed user close specified input grid files chooses ce highest rank quantity derived ce status information expresses goodness ce typically function numbers running queued jobs rb locates grid input files specified job description using service called data location interface dli provides generic interface file catalogue way resource broker talk file catalogs lfc provided dli interface recent implementation wms egee allows submission single jobs also collections jobs possibly dependencies much efficient way old lcg-2 wms many new options finally logging bookkeeping service lb tracks jobs managed wms collects events many wms components records status history job glite components services contributing partners
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Distributed computing architecture
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singleton variable computer programming singleton variable variable referred examples variable might referenced dummy argument function call address assigned another variable subsequently accesses allocated storage singleton variables sometimes occur mistake made – assigning value variable forgetting use later mistyping one instance variable name compilers lint-like tools flag occurrences singleton variables
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Programming language topics
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security shield security shield also known securityshield series rogue security software programs asks amount money get full version protection minor non-existent viruses
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Computer security
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scm scheme implementation scm programming language dialect language scheme written language c aubrey jaffer author slib scheme library jacal interactive computer algebra symbolic mathematics program conforms standards r4rs r5rs ieee p1178 free open-source software released gnu lesser general public license lgpl scm runs many different operating systems amigaos also emulation linux atari-st macos scm mac dos os/2 nos/ve unicos vms unix similar systems scm includes hobbit scheme-to-c compiler written originally 2002 tanel tammet generates c files binaries dynamically statically linked scm executable scm includes linkable modules slib features like sequence comparison arrays records byte-number conversions modules portable operating system interface posix system calls network sockets readline curses xlib platforms scm supports unexec developed emacs bash dumps executable image running scm results fast startup scm scm developed scheme one defun siod 1990 gnu guile developed scm 1993
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Programming language topics
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lessac technologies lessac technologies inc. lti american firm develops voice synthesis software licenses technology sells synthesized novels mp3 files firm currently seven patents granted lti technology partly based work late arthur lessac professor theater state university new york creator lessac kinesensic training lti licensed exclusive rights exploit arthur lessac copyrighted works fields speech synthesis speech recognition based view music speech speech music lessac work books focused body speech energies go together arthur lessac textual annotation system originally developed assist actors singers orators marking scripts prepare performance adapted lti speech synthesis system basic representation speech synthesized lessemes contrast many systems use phonetic representation lti ’ software two major components 1 linguistic front-end converts plain text sequence prosodic phonosensory graphic symbols lessemes based arthur lessac annotation system specify speech units synthesized 2 signal-processing back-end takes lessemes acoustic data produces human-sounding synthesized speech output using unit selection concatenation lti ’ text-to-speech system came second world-wide blizzard challenge 2011 2012 first-place team 2011 also employed lti front-end technology back-end blizzard challenge conducted language technologies institute carnegie mellon university devised way evaluate speech synthesis techniques different research groups build voices voice-actor recordings comparing results listening tests lti founded 2000 h. donald wilson chairman lawyer lexisnexis entrepreneur business associate arthur lessac gary a. marple chief inventor marple suggested arthur lessac kinesensic voice training might applicable computational linguistics wilson ’ death 2006 nephew john reichenbach became firm ’ ceo
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Computational linguistics
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paul graham programmer paul graham born 13 november 1964 english-born computer scientist entrepreneur venture capitalist author essayist best known work lisp former startup viaweb later renamed yahoo store co-founding influential startup accelerator seed capital firm combinator blog hacker news author several programming books lisp 1993 ansi common lisp 1995 hackers painters 2004 technology journalist steven levy described graham hacker philosopher paul graham family moved pittsburgh pennsylvania 1968 attended gateway high school graham received bachelor arts philosophy cornell university 1986 attended harvard university earning master science 1988 doctor philosophy 1990 degrees computer science also studied painting rhode island school design accademia di belle arti florence 1996 graham robert morris founded viaweb first application service provider asp viaweb software written mostly common lisp allowed users make internet stores summer 1998 viaweb sold yahoo 455,000 shares yahoo stock valued 49.6 million acquisition product became yahoo store later gained fame essays posts personal website paulgraham.com essay subjects range beating averages compares lisp programming languages introduced hypothetical programming language blub nerds unpopular discussion nerd life high school collection essays published hackers painters o'reilly includes discussion growth viaweb graham perceives advantages lisp program 2001 graham announced working new dialect lisp named arc years since written several essays describing features goals language internal projects combinator written arc notably hacker news web forum news aggregator program 2005 giving talk harvard computer society later published start startup graham along trevor blackwell jessica livingston robert morris started combinator provide seed funding large number startups particularly started younger technically oriented founders combinator invested 1300 startups including justin.tv xobni dropbox airbnb stripe businessweek included paul graham 2008 edition annual feature 25 influential people web 2008 paul graham married jessica livingston response proposed stop online piracy act sopa graham announced late 2011 representatives company supporting would invited combinator demo day events graham proposed disagreement hierarchy 2008 essay disagree putting types argument seven-point hierarchy observing moving disagreement hierarchy makes people less mean make happier graham also suggested hierarchy thought pyramid highest forms disagreement rarer following hierarchy graham notes articulate forms name-calling e.g author self-important dilettante different crude insults graham considers hierarchy programming languages example blub hypothetically average language right middle abstractness continuum powerful language powerful cobol machine language used graham illustrate comparison beyond turing completeness programming language power specifically illustrate difficulty comparing programming language one knows one one graham considers hypothetical blub programmer programmer looks power continuum considers lower languages less powerful miss feature blub programmer used looks fails realise looking merely sees weird languages unnecessary features assumes equivalent power hairy stuff thrown well graham considers point view programmer using language higher blub describes programmer looking blub noting missing features point view higher language graham describes blub paradox concludes induction programmers position see differences power various languages understand powerful one concept cited writers joel spolsky
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Programming language topics
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amd platform security processor amd platform security processor psp officially known amd secure technology trusted execution environment subsystem incorporated since 2013 amd microprocessors according amd developer guide subsystem responsible creating monitoring maintaining security environment functions include managing boot process initializing various security related mechanisms monitoring system suspicious activity events implementing appropriate response critics worry used backdoor security concern amd denied requests open source code runs psp psp similar intel management engine intel processors psp arm core inserted main cpu september 2017 google security researcher cfir cohen reported vulnerability amd psp subsystem could allow attacker access passwords certificates sensitive information patch rumored become available vendors december 2017 march 2018 handful alleged serious flaws announced amd zen architecture cpus epyc ryzen ryzen pro ryzen mobile israeli security company related psp could allow malware run gain access sensitive information amd announced firmware updates handle flaws claims flaws published purpose stock manipulation validity technical standpoint upheld independent security experts reviewed disclosures although high risks claimed cts labs often dismissed said independent experts
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Computer security
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ipad air 2019 third-generation ipad air tablet computer designed developed marketed apple inc announced march 18 2019 alongside 5th generation ipad mini device similar ipad air 2 10.5-inch ipad pro features apple a12 bionic chip 64 256 gb storage upgraded 10.5-inch retina display support apple pencil 1st generation bluetooth 5.0 faster memory lpddr4x instead ipad air 2 lpddr3 third-generation ipad air features upgraded front camera system 7mp 1080p camera used since 2016 starting iphone 7 continued iphone xs continues older 8mp 1080p rear camera system used since ipad air 2 2014 record 4k ipad air retains lightning port keeps headphone jack third-generation ipad air 2.49ghz six-core processor apple a12 bionic chip chip 66 faster clock speed 1.5ghz triple-core apple a8x third-generation ipad air predecessor ipad air 2 third-generation ipad air true tone display allows lcd adapt ambient lighting change color intensity different environments 3x faster ipad air 2 battery last 10 hours
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Operating systems
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tao exdos tao exdos emulator software application designed allow users old ms-dos applications run applications new operating systems windows 10 windows 8 windows 7 windows vista windows xp windows 2000 windows terminal server tao exdos enables users dos applications work applications new operating systems using built-in virtual 8086 mode x86 cpu tao exdos enables dos 16-bit windows applications run dos run effectively 32-bit windows desktop environments including windows 10/8/7/vista/xp/2000 windows terminal server 2003/2008 support 64-bit systems available windows 7 via virtual xp mode downloaded free microsoft windows 7 professional ultimate enterprise versions additional modules allow dos users print printers connected usb ports network printers fax printers pdf microsoft word html image files
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Computer architecture
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webos version history webos linux operating system smart devices formerly mobile operating system initially developed palm later acquired hewlett-packard lg electronics palm launched webos january 2009 various versions webos featured several devices including pre pixi veer phones hp touchpad tablet latest version 3.0.5 released 12 january 2012
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Operating systems
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javaserver pages standard tag library javaserver pages standard tag library jstl component java ee web application development platform extends jsp specification adding tag library jsp tags common tasks xml data processing conditional execution database access loops internationalization jstl developed java community process jcp java specification request jsr 52 may 8 2006 jstl 1.2 released followed jstl 1.2.1 dec 7 2011 jstl provides effective way embed logic within jsp page without using embedded java code directly use standardized tag set rather breaking java code leads maintainable code enables separation concerns development application code user interface total six jstl tag library descriptors addition jstl jcp following jsrs develop standard jsp tag libraries
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Programming language topics
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virus bulletin virus bulletin magazine prevention detection removal malware spam regularly features analyses latest virus threats articles exploring new developments fight viruses interviews anti-virus experts evaluations current anti-malware products virus bulletin founded 1989 monthly hardcopy magazine later distributed electronically pdf format monthly publication format discontinued july 2014 articles made available standalone pieces web site magazine located sophos headquarters abingdon oxfordshire uk co-founded owned jan hruska peter lammer co-founders sophos virus bulletin claims full editorial independence favour sophos products tests reviews technical experts anti-virus vendors written articles magazine also conducts comparison tests detection rates anti-virus software products manage detect 100 viruses wild without false alarming given vb100 award magazine holds annual conference late september early october computer security professionals recent years magazine conference branched discuss anti-spam security issues well malware notable previous speakers include mikko hyppönen eugene kaspersky graham cluley well representatives major anti-virus vendors
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Computer security
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icewall sso icewall sso web federated single sign-on software developed marketed hewlett packard enterprise globe released 1997 icewall sso evolved last 18 years.originally developed hp japan marketed global markets provides highly convenient comfortable yet highly secure environment since first release 1997 icewall sso seen adoption intranet b-to-c b-to-b many services globally 40 million user licenses sold far world latest version icewall sso 10.0 provides support new leading-edge technologies cloud virtualization icewall sso product line extended include windows support addition existing hp-ux linux versions furthermore support services icewall sso planned continue 2024 making product long stable service life latest version available 10.0 august 2010 supported platforms red hat enterprise linux hp-ux windows server icewall sso mainly reverse proxy type implementation configured work agent type well depending requirements icewall sso mainly consists two modules cgi process works reverse proxy accepts http/https requests web browser forwards backend applications.forwarder also handles loginprocess authorizations communicating authentication module mentioned daemon program accepts requests forwarder performs authentication getting user information certification db directory services rdb icp icewall cert protocol used forwarder authentication module
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Distributed computing architecture
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collaboration data objects collaboration data objects cdo previously known ole messaging active messaging application programming interface included microsoft windows microsoft exchange server products library allows developers access global address list server objects addition contents mailboxes public folders cdo technology building messaging collaboration applications cdo used separately connection outlook object model gain access outlook cdo part outlook object model n't provide event-based functionality outlook objects manipulated using cdo starting exchange 2007 neither messaging api mapi client libraries cdo 1.2.1 provided part base product installation available downloads
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Operating systems
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cube attack cube attack method cryptanalysis applicable wide variety symmetric-key algorithms published itai dinur adi shamir september 2008 preprint revised version preprint placed online january 2009 paper also accepted presentation eurocrypt 2009 cipher vulnerable output bit represented sufficiently low degree polynomial gf 2 key input bits particular describes many stream ciphers based lfsrs des aes believed immune attack works summing output bit value possible values subset public input bits chosen resulting sum linear combination secret bits repeated application technique gives set linear relations secret bits solved discover bits authors show cipher resembles random polynomial sufficiently low degree sets public input bits exist high probability discovered precomputation phase black box probing relationship input output various choices public secret input bits making use information construction cipher paper presents practical attack authors implemented tested stream cipher previous known attack would effective state 10,000 bit lfsr secret dense feedback polynomial filtered array 1000 secret 8-bit 1-bit s-boxes whose input based secret taps lfsr state whose output xored together bit lfsr initialized different secret dense quadratic polynomial 10 000 key iv bits lfsr clocked large secret number times without producing outputs first output bit given iv made available attacker short preprocessing phase attacker query output bits variety key iv combinations 2 bit operations required discover key cipher authors also claim attack version trivium reduced 735 initialization rounds complexity 2 conjecture techniques may extend breaking 1100 trivium 1152 initialization rounds maybe even original cipher best attack known trivium attack however embroiled two separate controversies firstly daniel j. bernstein disputes assertion previous attack 10,000-bit lfsr-based stream cipher existed claims attack reduced-round trivium n't give real reason think full trivium attacked claims cube paper failed cite existing paper xuejia lai detailing attack ciphers small-degree polynomials believes cube attack merely reinvention existing technique secondly dinur shamir credit michael vielhaber algebraic iv differential attack aida precursor cube attack dinur stated eurocrypt 2009 cube generalises improves upon aida however vielhaber contends cube attack attack another name however acknowledged parties involved cube use efficient linearity test blr test results new attack needing less time aida although substantial particular change remains dispute way cube aida differ vielhaber claims instance linear polynomials key bits obtained attack unusually sparse yet supplied evidence claims evidence appear forthcoming paper entitled algebraic iv differential attack aida attacking full trivium clear whether alleged sparsity applies ciphers trivium
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Computer security
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black onyx memory limitations another part game released separately platforms added magic system two parts announced allowed party explore wilderness allowed party take part arena battles sg-1000 version one last releases console succeeded portrait loretta english-language fan-translation made available sg-1000 version back-porting abandoned source files similar hobby conversion project colecovision system group called team pixelboy later used source files complete project released unofficial english-language colecovision game 2013 player create five-member party 4 members gbc ask friendly encounters join party fill empty slots party explore dungeons town utsuro ウツロ obtain legendary black onyx break curse binds town eternal night combat system concept distance bows similar missile weapons melee weapons shields armor however hospital town offer examinations display pcs stats bank town heroes deposit money protects money thieves interest deposits since time system labyrinth town several entrances hidden one locations town labyrinth six floors corresponding six colors computer display must solved proper order depends platform order create stairway black tower onyx resides black onyx adapted manga titled published gamest comics collection april 1999 drawn kouta hirano
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Computer architecture
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festi botnet festi botnet also known alias spamnost botnet mostly involved email spam denial service attacks festi botnet first discovered around autumn 2009 time estimated botnet consisted roughly infected machines spam volume capacity roughly 2.5 billion spam emails day recent estimates dated august 2012 display botnet sending spam unique ip addresses quarter total amount 1 million detected ip sending spam mails besides capable sending email spam research festi botnet demonstrated also capable performing denial service attacks
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Computer security
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continental circus continental circus racing simulation arcade game created manufactured taito 1987 1989 ports released amiga amstrad cpc atari st commodore 64 msx zx spectrum arcade version game comes upright sit-down models feature shutter-type 3d glasses hanging player head according computer video games 1988 world first three dimensional racing simulation home conversions continental circus lack full-on 3d special glasses arcade version circus common term racing france japan likely stemming latin term racecourse unrelated 1972 french film motor racing also called continental circus 2005 game made available playstation 2 xbox pc part taito legends in-game vehicle 1987 camel-sponsored honda/lotus 99t formula one car driven ayrton senna satoru nakajima due licensing reasons sponsor names camel delonghi intentionally misspelled prevent copyright infringement japanese law player must successfully qualify eight different races win beginning player must take 80th place better advance player advances worst possible position qualify player fails meet qualify timer runs game player however option continue player fails qualify final race game automatically player continue real f1 races car susceptible damage contact another car player hits car piece trackside scenery called pits let car smoke long catch fire message impending explosion appear either way fail make back hit another car crash explode costing several seconds also car reaches speeds excess 380 km/h speedometer turn yellow warning player let know car going much fast car hits another car behind collision send car devastating cartwheel explodes costing several seconds light going fast turn cause car lose grip road car loses grip spin control low chance wreck happening definitely take several seconds clock also time time thunderstorm occur causing track become wet causing car lose traction case message change tires appear player must immediately get pits change wet-tyres storm dies road covered puddles pose threat continental circus music race plays intro/outro music race vein pole position afterwards screen cuts start line race course announcement gentlemen start engines 30 seconds start spoken line lifted 1972 french documentary game bears name entire collection musical scores sound effects voice clips featured compilation soundtrack known 究極tiger -g.s.m.taito 2- musical score composed zuntata taito house band excerpts arcade soundtrack included sinclair user cover tape music home versions composed ben daglish game commercially successful number-two coinslot dedicated arcade game chart behind street fighter home conversion went number 2 uk sales chart behind power drift january 1989 issue sinclair user gave award 1988 cock-up year title continental circus appearing spell circuit incorrectly
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Computer architecture
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soname unix unix-like operating systems soname field data shared object file soname string used logical name describing functionality object typically name equal filename library prefix thereof e.g codice_1 soname often used provide version backwards-compatibility information instance versions 1.0 1.9 shared library codice_2 provide identical interfaces would soname e.g codice_3 system includes version 1.3 shared object filename codice_4 soname field shared object tells system used fill dependency binary originally compiled using version 1.2 note codice_5 particular case complex history see gnu c library application binary interface abi library changes backward-incompatible way soname would incremented e.g codice_6 codice_7 gnu linker uses codice_8 codice_9 specify library name field internally linker create codice_10 field populate codice_11 given shared object file one use following command get information within library file using objdump objdump -p libx.so.1.3 grep soname
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Operating systems
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usenet usenet worldwide distributed discussion system available computers developed general-purpose unix-to-unix copy uucp dial-up network architecture tom truscott jim ellis conceived idea 1979 established 1980 users read post messages called articles posts collectively termed news one categories known newsgroups usenet resembles bulletin board system bbs many respects precursor internet forums widely used today discussions threaded web forums bbss though posts stored server sequentially name comes term users network major difference bbs web forum usenet absence central server dedicated administrator usenet distributed among large constantly changing conglomeration servers store forward messages one another so-called news feeds individual users may read messages post messages local server operated commercial usenet provider internet service provider university employer server usenet culturally historically significant networked world given rise popularized many widely recognized concepts terms faq flame sockpuppet spam 1990s internet became commonly affordable usenet connections via fidonet dial-up bbs networks made long-distance worldwide discussions communication widespread needing server local telephone service usenet conceived 1979 publicly established 1980 university north carolina chapel hill duke university decade world wide web went online general public received access internet making one oldest computer network communications systems still widespread use originally built poor man arpanet employing uucp transport protocol offer mail file transfers well announcements newly developed news software news name usenet emphasized creators hope usenix organization would take active role operation articles users post usenet organized topical categories known newsgroups logically organized hierarchies subjects instance sci.math sci.physics within sci hierarchy science talk.origins talk.atheism talk hierarchy user subscribes newsgroup news client software keeps track articles user read newsgroups majority articles responses article set articles traced one single non-reply article called thread modern newsreaders display articles arranged threads subthreads example wine-making newsgroup rec.crafts.winemaking someone might start thread called best yeast thread conversation might grow dozens replies long perhaps six eight different authors several days conversation different wine yeasts might branch several sub-threads tree-like form user posts article initially available user news server news server talks one servers newsfeeds exchanges articles fashion article copied server server eventually reach every server network later peer-to-peer networks operate similar principle usenet normally sender rather receiver initiates transfers usenet designed conditions networks much slower always available many sites original usenet network would connect twice day batch-transfer messages largely pots network typically used transfers phone charges lower night format transmission usenet articles similar internet e-mail messages difference two usenet articles read user whose news server carries group message posted opposed email messages one specific recipients today usenet diminished importance respect internet forums blogs mailing lists social media usenet differs media several ways usenet requires personal registration group concerned information need stored remote server archives always available reading messages require mail web client news client however possible read participate usenet newsgroups large degree using ordinary internet browsers since newsgroups copied several internet sites groups alt.binaries still widely used data transfer many internet service providers many internet sites operate news servers users access isps operate servers directly often offer users account another provider specifically operates newsfeeds early news implementations server newsreader single program suite running system today one uses separate newsreader client software program resembles email client accesses usenet servers instead clients mozilla thunderbird outlook express provide abilities isps run news servers news server one difficult internet services administer large amount data involved small customer base compared mainstream internet services email web access disproportionately high volume customer support incidents frequently complaining missing news articles isp fault isps outsource news operation specialist sites usually appear user though isp ran server many sites carry restricted newsfeed limited number newsgroups commonly omitted newsfeed foreign-language newsgroups alt.binaries hierarchy largely carries software music videos images accounts 99 percent article data also usenet providers specialize offering service users whose isps carry news carry restricted feed see also news server operation overview news systems implemented newsgroups typically accessed newsreaders applications allow users read reply postings newsgroups applications act clients one news servers although historically usenet associated unix operating system developed newsreaders available major operating systems modern mail clients communication suites commonly also integrated newsreader often however integrated clients low quality compared standalone newsreaders incorrectly implement usenet protocols standards conventions many integrated clients example one microsoft outlook express disliked purists misbehavior rise world wide web www web front-ends web2news become common web front ends lowered technical entry barrier requirements one application usenet nntp server account numerous websites offering web based gateways usenet groups although people begun filtering messages made web interfaces one reason another google groups one web based front end web browsers access google groups via news protocol links directly minority newsgroups moderated meaning messages submitted readers distributed directly usenet instead emailed moderators newsgroup approval moderator receive submitted articles review inject approved articles properly propagated worldwide articles approved moderator must bear approved header line moderators ensure messages readers see newsgroup conform charter newsgroup though required follow rules guidelines typically moderators appointed proposal newsgroup changes moderators follow succession plan historically mod hierarchy existed usenet reorganization moderated newsgroups may appear hierarchy typically .moderated added group name usenet newsgroups big-8 hierarchy created proposals called request discussion rfd rfd required following information newsgroup name checkgroups file entry moderated unmoderated status group moderated least one moderator valid email address must provided information beneficial required includes charter rationale moderation policy group moderated discussion new newsgroup proposal follows finished members big-8 management board making decision vote either approve disapprove new newsgroup unmoderated newsgroups form majority usenet newsgroups messages submitted readers unmoderated newsgroups immediately propagated everyone see minimal editorial content filtering vs propagation speed form one crux usenet community one little cited defense propagation canceling propagated message usenet users use command news readers offer cancellation commands part article storage expires relatively short order anyway almost unmoderated usenet groups become collections spam usenet set protocols generating storing retrieving news articles resemble internet mail messages exchanging among readership potentially widely distributed protocols commonly use flooding algorithm propagates copies throughout network participating servers whenever message reaches server server forwards message network neighbors n't yet seen article one copy message stored per server server makes available demand typically local readers able access server collection usenet servers thus certain peer-to-peer character share resources exchanging granularity exchange however different scale modern peer-to-peer system characteristic excludes actual users system connect news servers typical client-server application much like email reader rfc 850 first formal specification messages exchanged usenet servers superseded rfc 1036 subsequently rfc 5536 rfc 5537 cases unsuitable content posted usenet support automated removal posting whole network creating cancel message although due lack authentication resultant abuse capability frequently disabled copyright holders may still request manual deletion infringing material using provisions world intellectual property organization treaty implementations united states online copyright infringement liability limitation act would require giving notice individual news server administrator internet usenet transported via network news transfer protocol nntp tcp port 119 standard unprotected connections tcp port 563 ssl encrypted connections offered sites major set worldwide newsgroups contained within nine hierarchies eight operated consensual guidelines govern administration naming current big eight see also great renaming alt hierarchy subject procedures controlling groups big eight result less organized groups alt hierarchy tend specialized specific—for example might newsgroup big eight contains discussions children books group alt hierarchy may dedicated one specific author children books binaries posted alt.binaries making largest hierarchies many hierarchies newsgroups distributed alongside regional language-specific hierarchies ne serve specific countries regions japan malta new england companies projects administer hierarchies discuss products offer community technical support historical hierarchy free software foundation microsoft closed newsserver june 2010 providing support products forums users prefer use term usenet refer big eight hierarchies others include alt well general term netnews incorporates entire medium including private organizational news systems informal sub-hierarchy conventions also exist *.answers typically moderated cross-post groups faqs faq would posted within one group cross post *.answers group head hierarchy seen refining information news group subgroups recursive—to point silliness alt.* usenet originally created distribute text content encoded 7-bit ascii character set help programs encode 8-bit values ascii became practical distribute binary files content binary posts due size often-dubious copyright status time restricted specific newsgroups making easier administrators allow disallow traffic oldest widely used encoding method binary content uuencode unix uucp package late 1980s usenet articles often limited 60,000 characters larger hard limits exist today files therefore commonly split sections require reassembly reader header extensions base64 quoted-printable mime encodings new generation binary transport practice mime seen increased adoption text messages avoided binary attachments operating systems metadata attached files use specialized encoding formats mac os binhex special mime types used lesser known encoding systems may used one time btoa xx encoding boo usr encoding attempt reduce file transfer times informal file encoding known yenc introduced 2001 achieves 30 reduction data transferred assuming 8-bit characters safely transferred across network without first encoding 7-bit ascii space common method uploading large binary posts usenet convert files rar archives create parchive files parity files used recreate missing data every part files reaches server news server generally allocates certain amount storage space post content newsgroup storage filled time new post arrives old posts deleted make room new content network bandwidth available server high storage allocation small possible huge flood incoming content overflow allocation push everything group flood large enough beginning flood begin deleted even last part flood posted binary newsgroups able function reliably sufficient storage allocated group allow readers enough time download parts binary posting flushed group storage allocation one time posting undesired content countered newsgroup would flooded random garbage data posts sufficient quantity push content suppressed compensated service providers allocating enough storage retain everything posted day including spam floods without deleting anything average length time posts able stay group deleted commonly called retention time generally larger usenet servers enough capacity archive several years binary content even flooded new data maximum daily speed available good binaries service provider must accommodate users fast connections 3 megabit also users slow connections 256 kilobit less need time download content period several days weeks major nsps retention time 4 years results 33 petabytes 33000 terabytes storage part long retention times well growing internet upload speeds usenet also used individual users store backup data practice called usenet backup ubackup commercial providers offer easy use online backup services storing data usenet free charge although access usenet may method requires user manually select prepare upload data anyone potentially download backup files data typically encrypted files uploaded uploader control files automatically copied usenet providers multiple copies spread different geographical locations around world—desirable backup scheme binary newsgroups used distribute completely legal user-created works open-source software public domain material binary groups used illegally distribute commercial software copyrighted media pornographic material isp-operated usenet servers frequently block access alt.binaries groups reduce network traffic avoid related legal issues commercial usenet service providers claim operate telecommunications service assert responsible user-posted binary content transferred via equipment united states usenet providers qualify protection dmca safe harbor regulations provided establish mechanism comply respond takedown notices copyright holders removal copyrighted content entire usenet network nearly impossible task due rapid propagation servers retention done server petitioning usenet provider removal removes one server retention cache others possible special post cancellation message distributed remove servers many providers ignore cancel messages standard policy easily falsified submitted anyone takedown petition effective across whole network would issued origin server content posted propagated servers removal content early stage would prevent propagation modern high speed links content propagated fast arrives allowing time content review takedown issuance copyright holders establishing identity person posting illegal content equally difficult due trust-based design network like smtp email servers generally assume header origin information post true accurate however smtp email usenet post headers easily falsified obscure true identity location message source manner usenet significantly different modern p2p services p2p users distributing content typically immediately identifiable users network address origin information usenet posting completely obscured unobtainable propagated past original server also unlike modern p2p services identity downloaders hidden view p2p services downloader identifiable others network address usenet downloader connects directly server server knows address connecting usenet providers keep usage logs make logged information casually available outside parties recording industry association america existence anonymising gateways usenet also complicates tracing postings true origin newsgroup experiments first occurred 1979 tom truscott jim ellis duke university came idea replacement local announcement program established link nearby university north carolina using bourne shell scripts written steve bellovin public release news form conventional compiled software written steve daniel truscott 1980 usenet connected arpanet connections usenet arpanet mark horton graduate student set connection began feeding mailing lists arpanet usenet fa arpanet identifier usenet gained 50 member sites first year including reed college university oklahoma bell labs number people using network increased dramatically however still longer usenet users could contribute arpanet uucp networks spread quickly due lower costs involved ability use existing leased lines x.25 links even arpanet connections 1983 thousands people participated 500 hosts mostly universities bell labs sites also growing number unix-related companies number hosts nearly doubled 940 1984 100 newsgroups existed 20 devoted unix computer-related topics least third recreation mesh uucp hosts rapidly expanded became desirable distinguish usenet subset overall network vote taken 1982 usenix conference choose new name name usenet retained established applied news name uucpnet became common name overall network addition uucp early usenet traffic also exchanged fidonet dial-up bbs networks mid-1990s almost 40,000 fidonet systems operation possible communicate millions users around world local telephone service widespread use usenet bbs community facilitated introduction uucp feeds made possible ms-dos implementations uucp ufgate uucp fidonet gateway fsuucp uupc 1986 rfc 977 provided network news transfer protocol nntp specification distribution usenet articles tcp/ip flexible alternative informal internet transfers uucp traffic since internet boom 1990s almost usenet distribution nntp early versions usenet used duke news software designed one two articles day matt glickman horton berkeley produced improved version called b news could handle rising traffic 50 articles day late 1983 message format offered compatibility internet mail improved performance became dominant server software c news developed geoff collyer henry spencer university toronto comparable b news features offered considerably faster processing early 1990s internetnews rich salz developed take advantage continuous message flow made possible nntp versus batched store-and-forward design uucp since time inn development continued news server software also developed usenet first internet community place many important public developments pre-commercial internet place tim berners-lee announced launch world wide web linus torvalds announced linux project marc andreessen announced creation mosaic browser introduction image tag revolutionized world wide web turning graphical medium many jargon terms common use internet originated popularized usenet likewise many conflicts later spread rest internet ongoing difficulties spamming began usenet sascha segan pc magazine said 2008 usenet dying years segan said people pointed eternal september 1993 beginning usenet decline segan believes pornographers software crackers began putting large non-text files usenet late 1990s usenet disk space traffic increased correspondingly internet service providers questioned needed host space pornography unauthorized software state new york opened investigation child pornographers used usenet many isps dropped usenet access access alt hierarchy response john biggs techcrunch said long folks think command line better mouse original text-only social network live aol discontinued usenet access 2005 may 2010 duke university whose implementation kicked usenet 30 years earlier decommissioned usenet server citing low usage rising costs 32 years usenet news service link university north carolina chapel hill news.unc.edu retired february 4 2011 time amount usenet traffic steadily increased number text posts made big-8 newsgroups averaged 1,800 new messages every hour average 25,000 messages per day however averages minuscule comparison traffic binary groups much traffic increase reflects increase discrete users newsgroup discussions instead combination massive automated spamming increase use .binaries newsgroups large files often posted publicly small sampling change measured feed size per day follows 2008 verizon communications time warner cable sprint nextel signed agreement attorney general new york andrew cuomo shut access sources child pornography time warner cable stopped offering access usenet verizon reduced access big 8 hierarchies sprint stopped access alt hierarchies stopped access alt.binaries hierarchies cuomo never specifically named usenet anti-child pornography campaign david dejean pc world said worry isps used cuomo campaign excuse end portions usenet access costly internet service providers high demand customers 2008 aol longer offered usenet access four providers responded cuomo campaign five largest internet service providers united states 50 u.s. isp marketshare june 8 2009 announced would longer provide access usenet service july 15 2009 aol announced would discontinue integrated usenet service early 2005 citing growing popularity weblogs chat forums on-line conferencing aol community tremendous role popularizing usenet 11 years earlier august 2009 verizon announced would discontinue access usenet september 30 2009 janet announced would discontinue usenet service effective july 31 2010 citing google groups alternative microsoft announced would discontinue support public newsgroups msnews.microsoft.com june 1 2010 offering web forums alternative primary reasons cited discontinuance usenet service general isps include decline volume actual readers due competition blogs along cost liability concerns increasing proportion traffic devoted file-sharing spam unused discontinued groups isps include pressure cuomo campaign child pornography one reasons dropping usenet feeds part services isps cox atlantic communications resisted 2008 trend eventually drop respective usenet feeds 2010 public archives usenet articles existed since early days usenet system created kenneth almquist late 1982 distributed archiving usenet posts suggested november 1982 scott orshan proposed every site keep articles posted forever also november year rick adams responded post asking anyone archived netnews anyone plan stating afraid admit started archiving 'useful newsgroups september 18 june 1982 gregory g. woodbury proposed automatic access archives system consisted automatic answering fixed-format messages special mail recipient specified machines 1985 two news archiving systems one rfc posted internet first system called keepnews mark m. swenson university arizona described program attempts provide sane way extracting keeping information comes usenet main advantage system allow users mark articles worthwhile retain second system ya news archiver chuq von rospach similar keepnews designed work much larger archives wonderful quadratic search time feature unix ... becomes real problem von rospach early 1985 posted detailed rfc archiving accessing usenet articles keyword lookup rfc described program could generate maintain archive usenet articles allow looking articles based article-id subject lines keywords pulled article also included c code internal data structure system desire fulltext search index archived news articles new either one request made april 1991 alex martelli sought build sort keyword index news archive early may mr. martelli posted summary responses usenet noting popular suggestion award must definitely go 'lq-text package liam quin recently posted alt.sources huge site http //asstr.org archives indexes erotic pornographic stories posted usenet group alt.sex.stories today archiving usenet led fear loss privacy archive simplifies ways profile people partly countered introduction x-no-archive yes header controversial web-based archiving usenet posts began 1995 deja news large searchable database 2001 database acquired google google groups hosts archive usenet posts dating back may 1981 earliest posts date may 1981 june 1991 donated google university western ontario help david wiseman others originally archived henry spencer university toronto zoology department archives late 1991 early 1995 provided kent landfield netnews cd series jürgen christoffel gmd archive posts march 1995 onward started company dejanews later deja purchased google february 2001 google began archiving usenet posts starting second week august 2000 google criticized vice wired contributors well former employees stewardship archive breaking search functionality usenet whole administrators server administrator free whatever pleases long end users peer servers tolerate accept nevertheless famous administrators
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Internet protocols
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winlogon computing winlogon component microsoft windows operating systems responsible handling secure attention sequence loading user profile logon optionally locking computer screensaver running requiring another authentication step actual obtainment verification user credentials left components winlogon common target several threats could modify function memory usage increased memory usage process might indicate hijacked windows vista later operating systems winlogon roles responsibilities changed significantly winlogon handles interface functions independent authentication policy creates desktops window station implements time-out operations versions windows prior windows vista provides set support functions gina takes responsibility configuring machine user group policy winlogon also checks copy windows legitimate license windows xp later versions winlogon following responsibilities
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Computer security
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intel core microarchitecture intel core microarchitecture previously known next-generation micro-architecture multi-core processor microarchitecture unveiled intel q1 2006 based yonah processor design considered iteration p6 microarchitecture introduced 1995 pentium pro high power consumption heat intensity resulting inability effectively increase clock speed shortcomings inefficient pipeline primary reasons intel abandoned netburst microarchitecture switched completely different architectural design delivering high efficiency small pipeline rather high clock speeds core microarchitecture never reached clock speeds netburst microarchitecture even moving 45 nm lithography however many generations successor microarchitectures developed core basis nehalem sandy bridge intel managed surpass clock speeds netburst using devil canyon improved version haswell microarchitecture reached base frequency 4 ghz maximum tested frequency 4.4 ghz using 22 nm lithography ultimately derives p6 microarchitecture core microarchitecture many succeeding improvements first processors used architecture code-named 'merom 'conroe 'woodcrest merom mobile computing conroe desktop systems woodcrest servers workstations architecturally identical three processor lines differ socket used bus speed power consumption mainstream core-based processors branded pentium dual-core pentium low end branded celeron server workstation core-based processors branded xeon intel first 64-bit desktop mobile core-based processors branded core 2 core microarchitecture returned lower clock rates improved usage available clock cycles power compared preceding netburst microarchitecture pentium 4/d-branded cpus core microarchitecture provides efficient decoding stages execution units caches buses reducing power consumption core 2-branded cpus increasing processing capacity intel cpus varied widely power consumption according clock rate architecture semiconductor process shown cpu power dissipation tables like last netburst cpus core based processors feature multiple cores hardware virtualization support marketed intel vt-x well intel 64 ssse3 however core-based processors hyper-threading technology found pentium 4 processors core microarchitecture descendant p6 microarchitecture used pentium pro pentium ii pentium iii pentium m. l1 cache size enlarged core microarchitecture 32 kb pentium ii iii 16 kb l1 data 16 kb l1 instruction 64 kb l1 cache/core 32 kb l1 data 32 kb l1 instruction pentium core/core 2 consumer version also lacks l3 cache found gallatin core pentium 4 extreme edition though exclusively present high-end versions core-based xeons l3 cache hyper-threading reintroduced consumer line nehalem microarchitecture core microarchitecture major architectural revision based part pentium processor family designed intel israel penryn pipeline 12–14 stages long — less half prescott signature feature wide order execution cores penryn successor nehalem borrowed heavily pentium 4 20-24 pipeline stages core execution unit 4 issues wide compared 3-issue cores p6 pentium 2-issue cores netburst microarchitectures new architecture dual core design linked l1 cache shared l2 cache engineered maximum performance per watt improved scalability one new technology included design macro-ops fusion combines two x86 instructions single micro-operation example common code sequence like compare followed conditional jump would become single micro-op unfortunately technology work 64-bit mode new technologies include 1 cycle throughput 2 cycles previously 128-bit sse instructions new power saving design components run minimum speed ramping speed dynamically needed similar amd cool n'quiet power-saving technology well intel speedstep technology earlier mobile processors allows chip produce less heat consume little power possible woodcrest cpus front side bus fsb runs 1333 mt/s however scaled 1066 mt/s lower end 1.60 1.86 ghz variants merom mobile variant initially targeted run fsb 667 mt/s second wave meroms supporting 800 mt/s fsb released part santa rosa platform different socket may 2007 desktop-oriented conroe began models fsb 800 mt/s 1066 mt/s 1333 mt/s line officially launched july 22 2007 power consumption new processors extremely low—average use energy consumption 1–2 watt range ultra low voltage variants thermal design powers tdps 65 watts conroe woodcrests 80 watts 3.0 ghz woodcrest 40 watts low-voltage woodcrest comparison amd opteron 875he processor consumes 55 watts energy efficient socket am2 line fits 35 watt thermal envelope specified different way directly comparable merom mobile variant listed 35 watts tdp standard versions 5 watts tdp ultra low voltage ulv versions previously intel announced would focus power efficiency rather raw performance however idf spring 2006 intel advertised promised numbers processors core microarchitecture categorized number cores cache size socket combination unique code name product code used across number brands instance code name allendale product code 80557 two cores 2 mb l2 cache uses desktop socket 775 marketed celeron pentium core 2 xeon different sets features enabled mobile desktop processors come two variants differ size l2 cache specific amount l2 cache product also reduced disabling parts production time wolfdale-dp quad-core processors except dunnington qc multi-chip modules combining two dies 65 nm processors product code shared processors different dies specific information one used derived stepping original core 2 processors based around dies identified cpuid family 6 model 15 depending configuration packaging code names conroe lga 775 4 mb l2 cache allendale lga 775 2 mb l2 cache merom socket 4 mb l2 cache kentsfield multi-chip module lga 775 2x4mb l2 cache merom allendale processors limited features found pentium dual core celeron processors conroe allendale kentsfield also sold xeon processors additional code names processors based model woodcrest lga 771 4 mb l2 cache clovertown mcm lga 771 2×4mb l2 cache tigerton mcm socket 604 2×4mb l2 cache marketed xeon brand conroe-l merom-l processors based around core conroe merom contain single core 1 mb l2 cache significantly reducing production cost power consumption processor expense performance compared dual-core version used ultra-low voltage core 2 solo u2xxx celeron processors identified cpuid family 6 model 22 intel tick-tock cycle 2007/2008 tick shrink core microarchitecture 45 nanometers cpuid model 23 core 2 processors used code names penryn socket p wolfdale lga 775 yorkfield mcm lga 775 also sold celeron pentium xeon processors xeon brand wolfdale-dp harpertown code names used lga 771 based mcms two four active wolfdale cores architecturally 45nm core 2 processors feature sse4.1 new divide/shuffle engine chips come two sizes 6 mb 3 mb l2 cache smaller version commonly called penryn-3m wolfdale-3m well yorkfield-6m respectively single-core version penryn listed penryn-l separate model like merom-l version penryn-3m model one active core xeon dunnington processor cpuid family 6 model 29 closely related wolfdale comes six cores on-chip l3 cache designed servers socket 604 marketed xeon core 2 core microarchitecture uses number steppings unlike previous microarchitectures represent incremental improvements also different sets features like cache size low power modes steppings used across brands typically disabling features limiting clock frequencies low-end chips steppings reduced cache size use separate naming scheme means releases longer alphabetic order additional steppings used internal engineering samples listed tables many high-end core 2 xeon processors use multi-chip modules two three chips order get larger cache sizes two cores early es/qs steppings b0 cpuid 6f4h b1 6f5h e0 6f9h steppings b2/b3 e1 g0 model 15 cpuid 06fx processors evolutionary steps standard merom/conroe die 4 mib l2 cache short-lived e1 stepping used mobile processors stepping l2 m0 allendale chips 2 mib l2 cache reducing production cost power consumption low-end processors g0 m0 steppings improve idle power consumption c1e state add c2e state desktop processors mobile processors support c1 c4 idle states steppings e1 g0 m0 add support mobile intel 965 express santa rosa platform socket p earlier b2 l2 steppings appear socket based mobile intel 945 express napa refresh platform model 22 stepping a1 cpuid 10661h marks significant design change single core 1 mib l2 cache reducing power consumption manufacturing cost low-end like earlier steppings a1 used mobile intel 965 express platform steppings g0 m0 a1 mostly replaced older steppings 2008 2009 new stepping g2 introduced replace original stepping b2 model 23 cpuid 01067xh intel started marketing stepping full 6 mib reduced 3 mib l2 cache time giving identical cpuid values steppings new sse4.1 instructions stepping c1/m1 bug fix version c0/m0 specifically quad core processors used stepping e0/r0 adds two new instructions xsave/xrstor replaces earlier steppings mobile processors stepping c0/m0 used intel mobile 965 express santa rosa refresh platform whereas stepping e0/r0 supports later intel mobile 4 express montevina platform model 30 stepping a1 cpuid 106d1h adds l3 cache well six instead usual two cores leads unusually large die size 503 mm² february 2008 found way high-end xeon 7400 series dunnington conroe conroe xe allendale use socket lga 775 however every motherboard compatible processors supporting chipsets yorkfield xe model qx9770 45 nm 1600 mt/s fsb limited chipset compatibility x38 p35 overclocking high-performance x48 p45 motherboards compatible bios updates gradually released provide support penryn technology qx9775 compatible intel d5400xs motherboard wolfdale-3m model e7200 also limited compatibility least xpress 200 chipset incompatible although motherboard may required chipset support conroe motherboards based above-mentioned chipsets support conroe conroe-based processors require new power delivery feature set specified voltage regulator-down vrd 11.0 requirement result conroe significantly lower power consumption compared pentium 4/d cpus replaced motherboard supporting chipset vrd 11 supports conroe processors even boards need updated bios recognize conroe fid frequency id vid voltage id unlike previous pentium 4 pentium design core 2 technology sees greater benefit memory running synchronously front side bus fsb means conroe cpus fsb 1066 mt/s ideal memory performance ddr2 pc2-8500 configurations using pc2-5300 instead pc2-4200 actually decrease performance going pc2-6400 significant performance increase ddr2 memory models tighter timing specifications improve performance difference real world games applications often negligible optimally memory bandwidth afforded match bandwidth fsb say cpu 533 mt/s rated bus speed paired ram matching rated speed example ddr2 533 pc2-4200 common myth installing interleaved ram offer double bandwidth however increase bandwidth installing interleaved ram roughly 5–10 agtl+ psb used netburst processors well current medium-term pre-quickpath core 2 processors provide 64-bit data path current chipsets provide couple either ddr2 ddr3 channels jobs requiring large amounts memory access quad-core core 2 processors benefit significantly using pc2-8500 memory runs exactly speed cpu fsb officially supported configuration number motherboards support core 2 processor require use ddr2 intel 975x p965 chipsets require memory motherboards chipsets support core 2 processors ddr memory using ddr memory performance may reduced lower available memory bandwidth core 2 memory management unit mmu x6800 e6000 e4000 processors operate previous specifications implemented previous generations x86 hardware may cause problems many serious security stability issues existing operating system software intel documentation states programming manuals updated coming months information recommended methods managing translation lookaside buffer tlb core 2 avoid issues admits rare instances improper tlb invalidation may result unpredictable system behavior hangs incorrect data among issues stated intel errata ax39 ax43 ax65 ax79 ax90 ax99 said particularly serious 39 43 79 cause unpredictable behavior system hang fixed recent steppings among stated errata particularly serious openbsd theo de raadt dragonfly bsd matthew dillon taking contrasting view linus torvalds calling tlb issue totally insignificant adding biggest problem intel documented tlb behavior better microsoft issued update kb936357 address errata microcode update performance penalty bios updates also available fix issue
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Computer architecture
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