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personal firewall personal firewall application controls network traffic computer permitting denying communications based security policy typically works application layer firewall personal firewall differs conventional firewall terms scale personal firewall usually protect computer installed compared conventional firewall normally installed designated interface two networks router proxy server hence personal firewalls allow security policy defined individual computers whereas conventional firewall controls policy networks connects per-computer scope personal firewalls useful protect machines moved across different networks example laptop computer may used trusted intranet workplace minimal protection needed conventional firewall already place services require open ports file printer sharing useful laptop could used public wi-fi hotspots time decide level trust set individual security policies network unlike network firewalls many personal firewalls able control network traffic allowed programs secured computer application attempts outbound connection firewall may block blacklisted ask user whether blacklist yet known protects malware implemented executable program personal firewalls may also provide level intrusion detection allowing software terminate block connectivity suspects intrusion attempted common personal firewall features firewalls help protecting internal network hackers however firewall limitations mid 1990s part information security architecture project fortune 100 corporation united states anheuser-busch corporation one members three-man architectural development team came concept regards improving overall security operating system used computers within networked system network system referred budnet improving overall security operating system commonly referred os hardening member team charged ssgt donald r. woeltje jr. concept came installation special software firewall software every budnet server workstation perimeter security device indeed every single windows system budnet network concept commonly referred personal firewall software ssgt woeltje invent personal firewall software invent idea personal firewall evidence fact exists anheuser-busch security model proposal document made ssgt woeltje time ssgt woeltje brought leading firewall vendors meetings concerning products considered use perimeter security budnet network ssgt woeltje brought concept personal firewall vendors asked firewall product could used way exception representatives cyberguard corporation every vendor said firewall software could used way also said idea crazy unworkable today know wrong use personal firewall software become de facto computer security standard companies ssgt woeltje discussed personal firewall software among others cisco checkpoint axent technologies milkyway networks cyberguard network one trusted information systems secure computing corporation
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Computer security
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ios 11 ios 11 eleventh major release ios mobile operating system developed apple inc. successor ios 10 announced company worldwide developers conference june 5 2017 released september 19 2017 succeeded ios 12 september 17 2018 among ios 11 changes lock screen notification center combined allowing notifications displayed directly lock screen various pages control center unified gaining custom settings ability 3d touch icons options app store received visual overhaul focus editorial content daily highlights files file manager app allowed direct access files stored locally cloud services siri updated translate languages use privacy-minded on-device learning technique better understand user interests offer suggestions camera new settings improved portrait-mode photos utilised new encoding technologies reduce file sizes newer devices later release messages integrated icloud better synchronize messages across ios macos devices previous point release also added support person-to-person apple pay payments operating system also introduced ability record screen limited forms drag-and-drop functionality support augmented reality certain new features appeared ipad including always-accessible application dock cross-app drag-and-drop new user interface show multiple apps ios 11 received mixed reviews critics significantly praised application dock new multitasking interface ipad crediting renewing user experience praise directed redesigned control center offering customizable toggles though criticized lack third-party app support lack wi-fi network selection ability difficult usage small screen sizes along instability critics also noted new augmented reality development tools said impact would depend third-party apps fast developers embraced praise also directed app store redesign new file-management tools shortly release discovered disabling wi-fi bluetooth connections control center disable respective chips device order remain functional background connectivity design decision sparking criticism misleading users reducing security due potential vulnerabilities inactive open connections ios 11.2 update added warning messages new toggle color explain new functions ios 11 also received continuous criticism critics end-users perceived stability performance issues particularly older devices apple issued numerous software updates address issues dedicated ios 12 mainly toward stability performance improvements response two months release 52 ios devices running ios 11 slower adoption rate previous ios versions number increased 85 devices september 2018 june 4 2018 worldwide developers conference apple announced successor ios 12. ios 11 introduced apple worldwide developers conference keynote address june 5 2017 first developer beta version released keynote presentation first public beta released june 26 2017. ios 11 officially released september 19 2017. ios 11.0.1 released september 26 2017 first update ios 11 update contained bug fixes improvements including fix bug prevented emails sent exchange servers ios 11.0.2 released october 3 2017 mainly fixed crackling earpiece issue affected iphone 8 8 plus units ios 11.0.3 released october 11 2017 fixed issue audio haptic feedback iphone 7 7 plus issue iphone 6s touch input unresponsive device display serviced non-genuine apple parts ios 11.1 released october 31 2017 added 70 new emoji fixed krack wi-fi vulnerability reintroduced 3d touch multitasking gesture incorporated bug fixes ios 11.1.1 released november 9 2017 fixed keyboard autocorrect bug hey siri malfunction ios 11.1.2 released november 16 2017 fixed display issue iphone x screen would become unresponsive due rapid temperature drop well fixing issue distortion live photos videos captured iphone x. ios 11.2 released december 2 2017 added apple pay cash enabled faster 7.5w wireless charging introduced new live wallpapers iphone x two new pop-ups added explain new functionality wi-fi bluetooth control center toggles app store allows user pre-order app yet available app available app automatically downloaded tv app includes sports section update also included bug fixes calculator bug i.t autocorrect bug december 2 crash bug ios 11.2.1 released december 13 2017 update fixed remote access homekit devices following major security glitch also fixed camera autofocus iphone 8 8 plus x devices ios 11.2.2 released january 8 2018 update made changes safari webkit mitigate effects spectre attack ios 11.2.5 released january 23 2018 update fixed bugs added support homepod allows siri read news articles works us uk australia ios 11.2.6 released february 19 2018 update fixed bug caused applications crash processing particular character telugu script ios 11.3 released march 29 2018 update introduced battery health feature allows user disable performance throttling using older battery reveals issues iphone 6s battery recall ios 11.3 introduces new privacy icon displays whenever app using personal data update also includes arkit 1.5 gives better accuracy non-flat surfaces allows developers place objects vertical surfaces update adds new skeleton lion dragon bear animoji new health records feature allows patients view health records iphone available certain institutions new business chat feature allows customers interact certain business right messages app including customer support apple pay support added advanced mobile location supported countries ios 11.3.1 released april 24 2018 update improves security addresses issue touch input unresponsive iphone 8 devices serviced non-genuine displays ios 11.4 released may 29 2018 messages stored icloud airplay 2 brings support multi-room homepod speakers apple tv homepod stereo speaker pair pairs homepod syncing updating latest version command siri play song room ios 11.4.1 released july 9 2018 fixes issue prevented users viewing last known location airpods find phone app improves reliability syncing mail contacts notes exchange accounts lock screen notification center combined allowing users see notifications directly lock screen scrolling either show hide notifications control center redesign unifies pages allows users 3d touch long press devices without 3d touch buttons options sliders adjust volume brightness control center customizable via settings app allows settings shown including cellular service low power mode shortcut notes app siri intelligent personal assistant human voice supports language translation english chinese french german italian spanish available launch also support follow-up questions users users also able type siri siri able use on-device learning privacy-minded local learning technique understand user behavior interests inside different apps offer better suggestions recommendations new disturb driving mode lets users block unnecessary notifications long iphone connected vehicle bluetooth auto-reply feature sends specific reply senders messages let know user currently unavailable text passengers granted full notification access phone new smart invert feature dubbed dark mode publications inverts colors display except images apps user interface elements using iphone x utilizes oled technology news outlets reported feature conserve battery life turning pixels black saving energy preventing displaying white pixel users get expanded control apps location usage every app featuring using app location toggle settings differs previous ios versions apps required never always location options users remove rarely-used apps without losing app data using offload app button allows later reinstallation app available app store data returns usage continue users also apps removed automatically offload unused apps setting app offloaded app appears home screen grayed-out icon personalized suggestions help user free storage space device including emptying photos trash backing messages enabling icloud photo library backing photos videos certain new ios 11 features appear ipad application dock gets overhaul bringing closer design seen macos accessible screen letting users easily open apps split-screen view users also drag-and-drop files across different apps new multitasking interface shows multiple apps screen time floating windows additionally combination slide split view picture-in-picture modes users four active apps on-screen time letter ipad keyboard features alternative background number symbol accessible pulling respective key releasing control center visible multitasking window ipads running ios 11 9.7-inch 10.5-inch 2nd-generation 12.9-inch ipad pros flashlight support ios 11 introduces optical image stabilization flash photography high dynamic range portrait photos live photos receives new loop bounce long exposure effects uses high efficiency image file format decrease photo sizes devices apple a10 chip newer photos compressed new high efficiency image file format videos encoded new high efficiency video coding video compression format enabling improved quality also decreasing size half apple significantly changed wallpapers available use ios 11 initial beta version released apple developer conference apple included one new wallpaper removed six live animated fish wallpapers introduced iphone 6s 2015 ios 11.2 release later brought iphone x/8/8 plus-exclusive wallpapers older iphones iphone x exclusively features six live wallpapers seven new dynamic wallpapers ios 11 introduces native support qr code scanning camera app qr code positioned front camera notification created offering suggestions actions based scanned content twitter users far discovered joining wi-fi networks adding someone contacts list supported qr codes third-party keyboards add one-handed mode users able record screen natively order record screen users must first add feature control center settings app added users start stop recordings dedicated control center icon distinctly colored bar appearing top screen indicating active recording pressing bar gives option end recording videos saved photos app ios 11 device attempting connect wi-fi network nearby ios 11 macos high sierra devices already connected wirelessly send password streamlining connection process volume change overlay longer covers screen playing video smaller scrubber appears top right screen user takes screenshot thumbnail screenshot appear bottom left screen user tap thumbnail bring interface allows crop annotate delete screenshot third-party apps also able take advantage icloud keychain allow autofilling passwords user airline flight information viewed spotlight dedicated widget ios 11 switches top-left cellular network strength icons five dots four signal bars similar ios 7 new automatic setup feature aims simplify first-time setup new devices wireless transfer old new device transferring preferences apple id wi-fi info preferred settings icloud keychain passwords similar ipad drag-and-drop file support available iphone though limitations specifically supported within apps many apple pre-installed applications including notes contacts reminders maps app store redesigned home screen icons emergency sos feature added disables touch id pressing sleep/wake button five times quick succession prevents touch id working iphone passcode entered ios 11 adds support 8-bit 10-bit hevc devices apple a9 chip newer support hardware decoding older devices support software-based decoding empty space mail app users draw inline messages application synchronizes messages across ios macos icloud reflecting message deletion across devices feature temporarily removed fifth beta release returned may 29 2018 ios 11.4 released time ios 11 announcement june 2017 apple presented functionality letting users send person-to-person payments apple pay messages time ios 11 release september 2017 feature present removed earlier beta version apple announcing feature coming fall update ios 11 launched days ios 11.2 update went live although initially available united states new app drawer imessage apps aims simplify experience using apps stickers optimized storage system reduces backup size messages messages app also incorporates business chat feature businesses communicate directly customers app accessed message icon next search results businesses however feature included initial release ios 11 instead launching ios 11.3 messages app iphone x introduces face-tracking emoji called animoji animated emoji using face id app store receives complete redesign greater focus editorial content daily highlights design described cleaner consistent apps developed apple app design mimics design seen apple music app ios 10 select locations apple maps offer indoor maps shopping malls airports new lane guidance speed limit features aim guide drivers unfamiliar roads photos app ios 11 gains support viewing animated gifs users access gif images inside album titled animated memories viewed phone portrait orientation podcasts app receives redesign similar app store focus editorial content notes app built-in document scanner using device camera feature removes artifacts glare perspective instant notes feature ipad pro allows user start writing note lock screen putting apple pencil onto screen app also allows users input inline tables open space notes app user draw inline new files app lets users browse files stored device well stored across various cloud services including icloud drive dropbox onedrive google drive app supports organization structured sub-folders various file-based options files app also includes built-in player flac audio files files app available ipad iphone user flight information found safari app calculator app receives redesign rounded buttons replacing grid ones seen ios 7 new arkit application programming interface api lets third-party developers build augmented reality apps taking advantage device camera cpu gpu motion sensors arkit functionality available users devices apple a9 later processors according apple processors deliver breakthrough performance enables fast scene understanding lets build detailed compelling virtual content top real-world scenes new core ml software framework speed app tasks involving artificial intelligence image recognition new depth api allows third-party camera app developers take advantage iphone 7 plus iphone 8 plus iphone x dual-camera portrait mode let apps implement depth-sensing technology available default ios camera app simulate shallow depth-of-field new core nfc framework gives developers limited access near field communication nfc chip inside supported iphones opening potential use cases apps scan nearby environments give users information apps must compiled 64-bit architecture order supported ios 11 32-bit apps supported shown app store ios 11 users attempt open apps receive alert app incompatibility ios 11 drops native system integration twitter facebook flickr vimeo icloud drive app removed replaced files app ability trigger multitasking using 3d touch removed original ios 11 release response bug report apple engineer wrote please know feature intentionally removed apple software engineering chief craig federighi wrote reply email company temporarily drop support due technical constraint pledging bring back future update ios 11 brought back ios 11.1 ios 11.2 toggle switch wi-fi bluetooth unexpectedly changed completely turning two things temporarily next day real turn settings app dieter bohn verge liked new control center setup including customizable toggles 3d touch-expandable options writing panels 'm really impressed specifically highlighting apple tv remote possible replacement normal remote however note lack third-party access control center hope support future lack wi-fi network selection ability praised screen-recording functionality calling super neat bohn severely criticized notifications view writing serious disagreement apple manage elaborating prefers use screen much possible stating apple philosophy 'm trying way hard control speedy notifications bohn liked new files app new drag-and-drop functionality home screen enabling users drag multiple apps significantly praised multitasking ipad writing multitasking ipad near-revelatory experience enjoyed application dock ability place three apps screen freedom placement bohn conceded intuitive simple easy manipulate traditional windowing system like 'll get mac pc chromebook still praised radically powerful ever available ipad finally bohn praised siri improvements voice highlighted augmented reality allowing incredible games reiterated earlier sentiment ios 11 ambitious software update apple long time macworld jason snell wrote hype surrounding ios 11 justified snell praised new smoother transfer mode data settings old iphone new iphone referring previous experience manually frustrating exercise entering passwords repeatedly tapping long series questions activating deactivating numerous ios features also praised control center design calling great upgrade though also highlighting inability easily switch wi-fi networks snell noted app store design unchanged years received full redesign ios 11 wrote apple commitment editorial pages impressive making app store richer fun experience regarding introduction augmented reality stated apps using bad though also mind-blowingly good adding huge potential depended third-party apps using snell also praised improvements ipad experience including multitasking drag-and-drop across apps latter stated actually surpasses expectations due ease use review summarization states ios 11 apple ’ ambitious impressive upgrade years romain dillet techcrunch focused mostly ipad review writing ios 11 turns ipad completely different machine much efficient multitasking improved ease access application dock also praised design overhaul app store calling huge improvement compared previous app store also highlighted design changes apps including huge bold header name app section although acknowledged many tech friends told hate change dillet stated think people like ’ visually pleasing distinctive stated augmented reality become relevant days following ios 11 release third-party developers incorporate features apps praised apple creating arkit development tools makes much easier implement augmented reality features conclusion dillet wrote ten years ago ios started constrained operating system one biggest digital playgrounds devindra hardawar engadget stated focus ios 11 transforming ios something desktop-like many enhancements ipad leaving iphone bit behind mixed feelings control center writing small phone screen sizes feels like jumbled mess adding true comfort may present larger screens troubling situation owners non-plus devices however praised ability customize buttons including removing user never uses ability quickly record screen enable accessibility features called new app designs attractive favorably pointed new app drawer bottom conversations messages app referring big improvement messy interface last year praised siri improved voice photos app creating better memories new social features apple music though noting lack people social circle using service referencing ikea ikea place app uses augmented reality virtually place objects room significantly praised performance augmented reality technology iphone writing great job rendering furniture physical spaces using iphone 8 even impressively ran smoothly iphone 6s finally hardawar also enjoyed new functionality ipad calling multitasking application dock drag-and-drop dramatic changes highlighting particularly useful experience dragging internet content directly web new files app summarization recognized significant strides made ipad ios 11 writing shame ios 11 n't bring table iphone though acknowledging rise augmented reality november 2017 apple app store support page updated reflect 52 ios devices running ios 11 slower migration rate release ios 10 year prior saw 60 user adoption october 2016 number increased 59 devices december 2017 september 2017 jesus diaz fast company criticized design details ios 11 apple built-in apps adhering apple user interface guidelines headers aligned properly different apps elements centered different colors sizing caused diaz write comes software apple ’ attention detail crumbling away however also looked back history mentioning apple music original design lack optical typography alignment calendar app previously-fixed ios design mistakes ported macos software established inconsistency lack attention detail new apple firmly stated perhaps inevitable given monumental task update operating system every year company claims obsessive attention detail acceptable november 2017 gizmodo adam clark estes wrote extensively software bugs product imperfections experienced using ios 11 estes pointed issues keyboard covering messages disappearing reply field messages app letter converting unicode symbol screen becoming unresponsive writing new operating system turned phone bug-infested carcass former self frustration trying use sometimes makes want die also wrote aspect technology becoming advanced sophisticated explaining back iphone 4 came ... smartphones lot simpler cameras joyfully crappy screens small number apps could download things could connect paltry compared today ... expect bugs guess complex pieces technology contain points failure ’ oversimplifying issue concluded theorizing technological development writing however trying understand exactly life computers veered dramatically days windows 95 nothing worked right golden age iphone 4 everything seemed perfect handful ios bugs make feel like world falling apart ... maybe ’ annoying thing whiny one ’ upset nothing seems perfect maybe maybe apple slipping wrong trust along shortly ios 11 released vice motherboard discovered new behaviors wi-fi bluetooth toggles control center users tap turn features ios 11 disconnects chips active connections disable respective chips device report states feature bug referencing documentation pages apple confirming new toggle behaviors means disconnect connections remain active airdrop transfers airplay streaming apple pencil input handoff features security researcher andrea barisani told motherboard new user interface obvious making user experience uncomfortable october 2017 electronic frontier foundation published article calling interface misleading bad user security due higher risk security vulnerabilities wi-fi bluetooth chips activated active use foundation recommended apple fix loophole connectivity writing simply question communicating better users giving control clarity want settings off-ish ios 11.2 changes behavior slightly turning toggles white showing warning message explains functions toggles control center toggles turned users experienced battery drain problems updating ios 11 poll website 70 9to5mac visitors reported decreased battery life updating new operating system however article featuring twitter complaints battery life daily express wrote honestly expected happens every year completely normal major ios releases hammer battery device much faster first days use forbes stating article days install new version ios idevice busy sorts housekeeping practically apps updates ios busy downloading installing background ... additionally install new version ios something called re-indexing process ios 11 comb data device cataloged quick spotlight searching article states good news things temporary within week launch 11.3.1 update users began reporting continued issues update regarding battery drainage reports indicated drains 57 3 3 minutes even users health battery measuring 96 noticed iphones draining around 1 per minute addition battery drains iphone users noticed devices excessive heat buildup recommended technology experts users upgrade software release version subsequent 11.3.1 unless specifically plagued 'third party display issue october 2017 users reported reddit quickly typing equation built-in ios calculator app gives incorrect answers notably making query 1+2+3 result 24 rather 6 analysts blamed animation lag caused redesign app ios 11 problem worked around typing numbers slowly downloading alternative calculator apps app store problem large amount bug reports filed apple employee chris espinosa indicated twitter company aware issue ios 11.2 fixed issue november 2017 users reported bug default ios keyboard pressing resulted system rendering text along incomprehensible symbol featuring question mark box symbol known variation selector 16 intended purpose merging two characters emoji apple acknowledged issue support document advising users set text replacement feature device keyboard settings temporary workaround company confirmed wall street journal devices using older ios 11 versions opposed latest 11.1 version time publication affected issue apple spokesperson announced fix released soon ios 11.1.1 released november 9 2017 fixing issue end month another keyboard autocorrection bug reported time replacing word i.t macrumors suggested users set text replacement feature way earlier autocorrection issue though report notes users insist solution solve problem fixed release ios 11.2 early december users wrote twitter reddit exactly 12:15 a.m. local time december 2 app store app sends local notifications would cause device repeatedly restart reddit users reported disabling notifications turning background app refresh would stop issue apple staff twitter reported bug date handling recommending users manually set date prior december 2 macrumors wrote issue looks like limited devices running ios 11.1.2 users 11.2 beta release affected ios 11.2 released day fixed issue december 2017 9to5mac uncovered security vulnerability ios 11.2 within apple homekit smart home system allowing unauthorized access smart locks garage door openers noted apple already issued server-side fix preventing unauthorized access also limited homekit functionality upcoming software fix ios operating system intended restore lost functionality december 13 apple released ios 11.2.1 fixed limitation remote access ios 11 drops support devices 32-bit processor specifically iphone 5 iphone 5c fourth-generation ipad first version ios run exclusively ios devices 64-bit processors
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Operating systems
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von duprin von duprin brand security products producer first panic bar style door mechanism allows door public building locked outside still easy exit inside 1903 iroquois theatre fire chicago claimed lives almost 600 people carl prinzler supposed attend show theatre fateful day however business dealings called elsewhere era common theatres like lock interior exterior doors prevent non-paying persons entering also inhibited persons inside exiting case iroquois theatre fire doors locked and/or bolted prevented patrons exiting causing burned alive succumb smoke inhalation prinzler astounded enormous senseless loss life night sought way doors public facilities locked outside allow egress inside minimal effort emergency prinzler tapped architectural engineering abilities henry h. dupont develop product 1908 first model panic bar style egress device released vonnegut hardware company utilized market owing joint effort develop sell product sold name von duprin combination names vonnegut dupont prinzler popular 88 series crossbar exit devices still manufactured von duprin look similar original design although significant engineering changes made von duprin continues manufacture security related products brand allegion plc
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Computer security
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hp business service automation hp business service automation collection software products data center automation hp software division hewlett-packard company products could help information technology departments create common enterprise-wide view business service enable automation change compliance across devices make business service connect processes coordinate teams via common workflows integrate monitoring ticketing tools form complete integrated business service management solution hp provides many capabilities part hp business service management software solutions longer competes past practices cost structures competes costs structures cloud computing software service saas providers hosts remain competitive determine retain outsource needs make systems applications perform better efficiently also needs automate applications systems keep complexity costs line visibility automation management essential regardless underlying infrastructure also allow function best broker services regardless servers may reside efficiencies type integration automation management led rise converged infrastructure environments type data center environment allows enterprises get applications running faster easier manageability less maintenance enables rapidly adjust resources servers storage networking meet fluctuating unpredictable business demand hp business service automation consisted several software products encompassed data center automation client automation runtime visibility control data center hp server automation software automates server lifecycle physical virtual servers automates deployment applications hp application deployment manager adm software automated release process bridge gap among development quality assurance operations teams hp network automation software delivers network change configuration management real-time visibility automation control network compliance security cost savings hp operations orchestration software process automation platform provides single view automating processes hybrid infrastructures including cloud computing environments hp radia client automation software persistent systems automates key processes across pc lifecycle hp storage essentials software standards-based storage resource management software provides visibility applications drilling host storage infrastructure hp database middleware automation software acquisition stratavia automates provisioning patching compliance configuration management heterogeneous databases application servers hp service automation visualizer software presented global interactive picture environment including servers software network devices storage configurations interdependencies hp business service automation bsa essentials provides content infrastructure services users includes portal security updates compliance policy checks content application management profiles bsa essentials reporting reporting engine ad hoc cross-domain analysis compliance reports
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Distributed computing architecture
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microsoft egypt microsoft egypt division microsoft markets microsoft products egypt microsoft established branch egypt 1995 office representative becoming limited liability company 1997 microsoft launched cairo microsoft innovation center september 2007 located smart village near cairo mission work concept-level research problems relatively short market headed tarek el-abbadi long time program manager microsoft redmond office
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Distributed computing architecture
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comparison instant messaging protocols following comparison instant messaging protocols contains basic general information protocols note 1 part known hostmask either server connected cloak granted server administrator realistic example tilde generally indicates username provided irc client signon verified ident service note 2 part resource distinguishes user logged multiple locations possibly simultaneously realistic example note 3 scalability issue protocol gets increasingly inefficient number contacts note 4 one-to-many/many-to-many communications primarily comprise presence information publish/subscribe groupchat distribution technologies ability distribute data multicast avoiding bottlenecks sending side caused number recipients efficient distribution presence currently however technological scalability issue xmpp sip/simple note 5 reports users antispam filter used censor links im programs websites note 6 serverless protocols n't central entities usually companies controlling network serverless network consists clients systems usually extremely resistant surveillance censorship
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Internet protocols
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language identification natural language processing language identification language guessing problem determining natural language given content computational approaches problem view special case text categorization solved various statistical methods several statistical approaches language identification using different techniques classify data one technique compare compressibility text compressibility texts set known languages approach known mutual information based distance measure technique also used empirically construct family trees languages closely correspond trees constructed using historical methods mutual information based distance measure essentially equivalent conventional model-based methods generally considered either novel better simpler techniques another technique described cavnar trenkle 1994 dunning 1994 create language n-gram model training text languages models based characters cavnar trenkle encoded bytes dunning latter language identification character encoding detection integrated piece text needing identified similar model made model compared stored language model likely language one model similar model text needing identified approach problematic input text language model case method may return another similar language result also problematic approach pieces input text composed several languages common web recent method see řehůřek kolkus 2009 method detect multiple languages unstructured piece text works robustly short texts words something n-gram approaches struggle older statistical method grefenstette based prevalence certain function words e.g. english one great bottlenecks language identification systems distinguish closely related languages similar languages like serbian croatian indonesian malay present significant lexical structural overlap making challenging systems discriminate recently dsl shared task organized providing dataset tan et al. 2014 containing 13 different languages language varieties six language groups group bosnian croatian serbian group b indonesian malaysian group c czech slovak group brazilian portuguese european portuguese group e peninsular spain argentine spanish group f american english british english best system reached performance 95 results goutte et al. 2014 results dsl shared task described zampieri et al 2014
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Computational linguistics
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key distribution center cryptography key distribution center kdc part cryptosystem intended reduce risks inherent exchanging keys kdcs often operate systems within users may permission use certain services times others instance administrator may established policy certain users may back tape many operating systems control access tape facility via system service system service restricts tape drive operate behalf users submit service-granting ticket wish use remains task distributing tickets appropriately permitted users ticket consists includes key one term mechanism distributes kdc usually situations kdc also operates system service typical operation kdc involves request user use service kdc use cryptographic techniques authenticate requesting users also check whether individual user right access service requested authenticated user meets prescribed conditions kdc issue ticket permitting access kdcs mostly operate symmetric encryption cases kdc shares key parties kdc produces ticket based server key client receives ticket submits appropriate server server verify submitted ticket grant access user submitting security systems using kdcs include kerberos actually kerberos partitions kdc functionality two different agents authentication server tgs ticket granting service
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Computer security
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motorola 56000 motorola dsp56000 also known 56k family digital signal processor dsp chips produced motorola semiconductor later known freescale semiconductor acquired nxp starting 1986 still produced advanced models 2010s 56k series quite popular time number computers including next atari falcon030 sgi indigo workstations using 56001 upgraded 56k versions still used audio equipment radars communications devices like mobile phones various embedded dsp applications 56000 also used basis updated 96000 commercially successful dsp56000 uses fixed-point arithmetic 24-bit program words 24-bit data words includes two 24-bit registers also referred single 48-bit register also includes two 56-bit accumulators 8-bit extension aka headroom otherwise accumulators similar 24/48-bit registers modified harvard architecture processor 56k three memory spaces+buses on-chip memory banks models program memory space/bus two data memory space/bus 24 bits selected basic word length gave system reasonable number range precision processing audio sound 56000 main concern 24 bits correspond large dynamic range sufficient 1980s analog-to-digital converters adcs digital-to-analog converters dacs rarely exceeded 20 bits one example adsl applications filters typically require 20 bits accuracy leftmost four bits considered ample headroom calculations processor capable carrying 16.5 million instructions per second mips maximum specified clock speed hardware support block-floating point fft uses ttl levels consumes approximately designs 56000 dedicated one single task digital signal processing using special hardware mostly real-time allow interruption somewhat mildly demanding tasks time-critical simple if-then type designers normally use separate cpu mcu 56000 execute 1024-point complex fast fourier transform fft takes rate 555 operations per second allowing realtime decoding encoding of/to reasonably advanced audio codecs mp3 direct-to-disc recording purposes addition simd instructions desktop computer cpus meant dedicated dsp chips like 56000 partly retreated application fields continue used widely communications professional uses end 56800 series added complete mcu created single-chip dspcontroller solution opposite occurred 68456—a 68000 56000 still quite prevalent model 56000 third generation 563xx family developed 2000s features several models special applications hard- firmware built-in like pci interface logic crc processors audio companders core clock frequencies ranged
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Computer architecture
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sedna database sedna open-source database management system provides native storage xml data distinctive design decisions employed sedna schema-based clustering storage strategy xml data ii memory management based layered address space data organization sedna designed goal providing balance performance xml queries updates execution two primary design decisions data organization sedna following figure illustrates overall principles data organization sedna descriptive schema represented tree schema nodes central component data organization schema node labeled xml node kind e.g element attribute text etc pointer data blocks store xml nodes corresponding given schema node depending node kind schema nodes also labeled names e.g. element nodes attribute nodes data blocks related common schema node linked via pointers bidirectional list node descriptors list blocks partly ordered according document order
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Databases
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page description language digital printing page description language pdl computer language describes appearance printed page higher level actual output bitmap overlapping term printer control language includes hewlett-packard printer command language pcl postscript one noted page description languages markup language adaptation pdl page description markup language page description languages text human-readable binary data streams usually intermixed text graphics printed distinct graphics application programming interfaces apis gdi opengl called software generate graphical output various page description languages exist
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Programming language topics
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open security open security use open source philosophies methodologies approach computer security information security challenges traditional application security based premise application service whether malware desirable relies security obscurity open source approaches created technology linux extent android operating system additionally open source approaches applied documents inspired wikis largest example wikipedia open security suggests security breaches vulnerabilities better prevented ameliorated users facing problems collaborate using open source philosophies approach requires users legally allowed collaborate relevant software would need released license widely accepted open source examples include massachusetts institute technology mit license apache 2.0 license gnu lesser general public license lgpl gnu general public license gpl relevant documents would need generally accepted open content license include creative commons attribution cc-by attribution share alike cc-by-sa licenses creative commons non-commercial licenses no-derivative licenses developer side legitimate software service providers independent verification testing source code information technology side companies aggregate common threats patterns security solutions variety security issues
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Computer security
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dmpl dmpl digital microprocessor plotter language vector graphics file format houston instruments developed control pen plotters later used cutting plotters language compatible hp-gl see eagle definition
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Programming language topics
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web services protocol stack web service protocol stack protocol stack stack computer networking protocols used define locate implement make web services interact web service protocol stack typically stacks four protocols web service protocol stack also includes whole range recently defined protocols bpel
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Web technology
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apple prodos prodos name two similar operating systems apple ii series personal computers original prodos renamed prodos 8 version 1.2 last official operating system usable 8-bit apple ii series computers distributed 1983 1993 prodos 16 stop-gap solution 16-bit apple ii replaced gs/os within two years prodos marketed apple meaning professional disk operating system became popular operating system apple ii series computers 10 months release january 1983 prodos released address shortcomings earlier apple operating system called simply dos beginning show age apple dos built-in support 5.25 floppy disks requires patches use peripheral devices hard disk drives non-disk-ii floppy disk drives including 3.5 floppy drives prodos adds standard method accessing rom-based drivers expansion cards disk devices expands maximum volume size 400 kilobytes 32 megabytes introduces support hierarchical subdirectories vital feature organizing hard disk storage space supports ram disks machines 128kb memory prodos addresses problems handling hardware interrupts includes well-defined documented programming expansion interface apple dos always lacked although prodos also includes support real-time clock rtc support went largely unused release apple ii first apple ii series include rtc board third-party clocks available ii plus iie iic however prodos unlike earlier apple dos versions developmental roots sos operating system ill-fated apple iii computer released 1980 pre-release documentation prodos including early editions beneath apple prodos documented sos error codes notably one switched disks prodos could never generate disk format programming interface completely different apple dos prodos read write dos 3.3 disks except means conversion utility low-level track-and-sector format dos 3.3 disks retained 5.25 inch disks high-level arrangement files directories completely different reason machine-language programs run apple dos work prodos however basic programs work though sometimes require minor changes third-party program called dos.master enables users multiple virtual dos 3.3 partitions larger prodos volume release prodos came end support integer basic original apple ii model long since effectively supplanted applesoft basic apple ii plus whereas dos 3.3 always loads built-in support basic programming prodos job given separate system program called basic.system one launches run write applesoft basic programs basic continued built apple roms basic.system merely command interpreter enhancement allows basic programs access prodos means control-d text output used dos 3.3 basic.system alone requires much memory whole dos 3.3 since prodos kernel stowed away language card ram usable amount ram basic programmers remains prodos dos 3.3 despite prodos many advantages many users programmers resisted time investment learning ins outs apple dos apple-dos-based software data formats contributing reason prodos allows 15 characters filename compared apple dos 30 apple integrated software package appleworks released 1984 proved compelling reason switch end 1985 new software products released older operating system apple iis continued able boot older dos even apple ii boot older dos floppies 3.5 floppies hard disks became prevalent users spent bulk time prodos apple iie also released 1983 first apple ii computer 64kb memory built apple shipped dos 3.3 prodos new computers original prodos renamed prodos 8 prodos 16 released support 16-bit apple ii computer although prodos 16 soon replaced gs/os editions prodos require apple ii series computer licensed compatible prodos 8 requires 64kb memory run original prodos 8 1.0 1.0.2 requires 48kb kernel nearly programs including basic.system needed use applesoft basic require 64kb making 48kb system useless prodos practical matter support 48kb machines removed version 1.1 prodos 8 version 2.x requires 65c02 later 65802 65816 cpu prodos 8 2.x runs 64kb utility programs system disk require 128kb systems 6502 cpu instead 65c02 must use prodos 8 versions prior version 2.0 unofficial prodos 8 2.4 released august 16 2016 removes 65c02 requirement run apple ii computers least 64 kb ram although basic.system still requires applesoft rom prodos 16 requires apple iigs release prodos version 1.01 higher check added see running official apple-manufactured computer word apple found computer rom firmware prodos load normal anything else found e.g golden franklin elite prodos refuses run locking boot splash screen measure taken apple computer discourage use unlicensed apple ii clones still possible run newer versions prodos clones however users apply small byte patch every successive version prodos users go far replacing physical rom chip illegal copied version apple rom failing custom patched rom apple added name prodos 8 natively supports disk ii-compatible floppy drives ram drive approximately 59kb computers 128k ram block devices whose controllers support pascal firmware protocol standardized method accepting block reads writes originally introduced use ucsd p-system latter category includes 3.5 disk hard drives custom block device drivers hooked os well prodos uses file system earlier apple sos apple iii sos/prodos file system native apple sos prodos 8 prodos 16 gs/os classic mac os versions also come file system translator handle file system volume allocated 512-byte blocks 5.25 floppy disks still formatted using 256-byte sectors format required controller rom boot disk prodos simply treats pairs 256-byte sectors single block drives volume capacity 32 megabytes file 16 megabytes volume floppy disk hard drive partition volume name filename used base directory name two volumes volume name result conflicts necessary prodos searches available drives find named volume subdirectories supported concept prefix working directory current path provided make working subdirectories easier file directory volume names 1 15 characters starting letter containing letters digits periods file entry also contains 16 bit 2 byte pointer block containing beginning file block index 16-bit block count 24-bit 3-byte file size 8-bit 1-byte filetype 16-bit auxiliary type meaning depends upon filetype creation modification timestamps data related file stored volume sparse files supported files never sparsified removing zero-filled blocks volume header contains similar information relevant volumes directories including root directory sequentially indexed block starting address previous block zero none subsequent block zero none root directory disks initialized 4 blocks allowing 51 entries excluding volume header never changes size except manual intervention special tools subdirectories begin one block grow automatically needed normal files progressively indexed single-block files 513 bytes index block directory entry points directly block file data files 2 256 blocks 513 bytes 128 kb data single index block directory entry points contains list 256 data block addresses larger files master index block containing list 256 index block addresses apple iigs introduced new storage format introduced files two forks typical iigs system program files directory entry points informational block tells computer storage format two forks files read written natively prodos 8 though volume remains compatible volume bitmap used blocks central file allocation table prodos 8 volume formatted apple tools boot sector supports booting prodos sos depending computer booted block 0 apple ii boot block block 1 boots sos allows disk used boot either apple ii apple iii computers putting operating system kernels top directory apple ii boot sector looks file prodos apple iii boot sector looks file sos.kernel third-party formatting utilities often provide sos boot block would even mark block 1 available user data prodos kernel support file systems necessary conversion utility main system disk used transfer files individually prodos older apple dos 3.3 disks use different low-level disk format dos 3.3 prodos transferring data dos 3.2 disks prodos two-step process using dos 3.3 disk intermediary utilizing dos 3.3 utility muffin similar
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Operating systems
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intervasion uk intervasion uk 1994 electronic civil disobedience collective action john major criminal justice bill sought outlaw outdoor dance festivals music repetitive beat launched group called zippies san francisco 181 club guy fawkes day november 5 1994 resulted government websites going least week utilised form distributed denial service ddos known email bomb order overload servers form online protest internet activism first use internet technology weapon struggle and/or civil disobedience preceded criminal justice public order act 1994 definition music played rave given music includes sounds wholly predominantly characterised emission succession repetitive beats sections 63 64 65 act targeted electronic dance music played raves criminal justice public order act empowered police stop rave open air ten people attending two making preparations rave section 65 allowed uniformed constable believes person way rave within radius stop direct away area non-compliant citizens may subject maximum fine exceeding level 3 standard scale £1000 zippies sought jam mailboxes uk politicians associated bill order bring attention issue natural justice involving basic rights freedoms effect collective action saying take away freedom power take away something take granted way deploys internet weapon several hackers directly associated group launched all-out penetration testing load testing operations several uk government websites resulting tit-for-tat battle zippies mailbox morph.com went along entire server morph well-known bay area bbs event broadcast radio free berkeley protest action occurred manhunt kevin mitnick thus partly underground event media also refused entertain implications electronic civil disobedience public attention focused problem illegal raves black-hat hackers prompting scare stories evil hackers young hoodlums penetrating british defences zippies written nothing electrohippies criticism intervasion expressed electronic frontier foundation complained lack cutoff date criticism whole earth 'lectronic link well bbs centered use militant language online protest action also suffered conflict stated aims clog servers uk government call send email messages uk politicians thus jamming mailboxes email large file attachments defeated purpose exercise essentially early form hacktivism nature collective action also articulated well enough instance digital be-in occurred launch timothy leary chaos cyberculture leary kidnapped without consent publisher forced ddos uk government simply protest message sent repeatedly mail-boxes around world
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Computer security
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proximic proximic platform provides real-time data services contextual data online advertisers agencies company based palo alto research development facilities munich company ceo philipp pieper co-founded company mathematician thomas nitsche thomas nitsche elmar henne proximic chief architect developed mephisto chess computer chief scientist louis monier founder altavista search engine proximic launched alpha testing mode late 2007 2010 company integrated real-time ad platform appnexus started offer contextual data services display advertisers agencies may 2015 proximic acquired comscore
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Web technology
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zeek zeek formerly bro free open-source software network analysis framework originally developed 1994 vern paxson named reference george orwell big brother novel nineteen eighty-four used network intrusion detection system nids additional live analysis network events released bsd license ip packets captured pcap transferred event engine accepts rejects accepted packets forwarded policy script interpreter event engine analyzes live recorded network traffic trace files generate neutral events generates events something happens triggered zeek process initialization termination zeek process well something taking place network trace file analyzed zeek witnessing http request new tcp connection zeek uses common ports dynamic protocol detection involving signatures well behavioral analysis make best guess interpreting network protocols events policy neutral good bad simply signals script land something happened events handled policy scripts analyze events create action policies scripts written turing complete zeek scripting language default zeek simply logs information events files zeek also supports logging events binary output however configured take actions sending email raising alert executing system command updating internal metric even calling another zeek script default behavior produces netflow-like output conn log well application event information zeek scripts able read data external files blacklists use within zeek policy scripts zeek analyzers located zeek event engine accompanying policy script policy script customized user analyzers perform application layer decoding anomaly detection signature matching connection analysis zeek designed easy add additional analyzers application layer analyzers included zeek http ftp smtp dns amongst others non-application layer analyzers include analyzers detect host port scans intermediary hosts syn-floods zeek also includes signature detection allows import snort signatures
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Computer security
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lispworks lispworks computer software proprietary implementation integrated development environment ide programming language common lisp lispworks developed uk software company harlequin ltd. first published 1989 harlequin ultimately spun lisp division xanalys ltd. took management rights lispworks january 2005 xanalys lisp team formed lispworks ltd. market develop support software lispworks features include enterprise edition also includes knowledgeworks supports rule-based logic programming including support prolog commonsql database interface common object request broker architecture corba binding september 2009 announced lispworks 6 would support concurrent threads capi graphics toolkit extended support gtk+ lispworks 6.1 released january 2012 includes many enhancements capi support anti-aliased drawing lispworks ran spacecraft deep space 1 application called rax nasa software year award 1999
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Programming language topics
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btrfs btrfs pronounced butter fuss better f butter f b-tree f simply spelling file system based copy-on-write cow principle initially designed oracle corporation use linux development btrfs began 2007 since november 2013 file system on-disk format marked stable btrfs intended address lack pooling snapshots checksums integral multi-device spanning linux file systems chris mason principal btrfs author stated goal let linux scale storage available scaling addressing storage also means able administer manage clean interface lets people see used makes reliable core data structure btrfsthe copy-on-write b-treewas originally proposed ibm researcher ohad rodeh presentation usenix 2007 chris mason engineer working reiserfs suse time joined oracle later year began work new file system based b-trees 2008 principal developer ext3 ext4 file systems theodore ts stated although ext4 improved features major advance uses old technology stop-gap ts said btrfs better direction offers improvements scalability reliability ease management btrfs also number design ideas reiser3/4 btrfs 1.0 finalized on-disk format originally slated late-2008 release finally accepted linux kernel mainline 2009 several linux distributions began offering btrfs experimental choice root file system installation july 2011 btrfs automatic defragmentation scrubbing features merged version 3.0 linux kernel mainline besides mason oracle miao xie fujitsu contributed performance improvements june 2012 chris mason left oracle fusion-io left year later josef bacik join facebook companies mason continued work btrfs 2012 two linux distributions moved btrfs experimental production supported status oracle linux march followed suse linux enterprise august 2015 btrfs adopted default filesystem suse linux enterprise server 12 august 2017 red hat announced release notes red hat enterprise linux rhel 7.4 longer planned move btrfs included technology preview since rhel 6 beta fully supported feature noting would remain available rhel 7 release series btrfs removed rhel 8 may 2019 version 5.0 linux kernel btrfs implements following features 2009 btrfs expected offer feature set comparable zfs developed sun microsystems oracle acquisition sun 2009 mason oracle decided continue btrfs development btrfs provides clone operation atomically creates copy-on-write snapshot file cloned files sometimes referred reflinks light associated linux kernel system calls cloning file system create new link pointing existing inode instead creates new inode initially shares disk blocks original file result cloning works within boundaries btrfs file system since version 3.6 linux kernel may cross boundaries subvolumes certain circumstances actual data blocks duplicated time due copy-on-write cow nature btrfs modifications cloned files visible original file vice versa cloning confused hard links directory entries associate multiple file names actual files file system hard links taken different names file cloning btrfs provides independent files share disk blocks support btrfs feature added version 7.5 gnu coreutils via codice_2 option codice_3 command btrfs subvolume thought separate posix file namespace mountable separately passing codice_4 codice_5 options utility also accessed mounting top-level subvolume case subvolumes visible accessible subdirectories subvolumes created place within file system hierarchy also nested nested subvolumes appear subdirectories within parent subvolumes similarly way top-level subvolume presents subvolumes subdirectories deleting subvolume possible subvolumes nesting hierarchy deleted result top-level subvolumes deleted btrfs file system always default subvolume initially set top-level subvolume mounted default subvolume selection option passed codice_6 default subvolume changed required btrfs snapshot subvolume shares data metadata subvolume using btrfs copy-on-write capabilities modifications snapshot visible original subvolume writable snapshot made treated alternate version original file system example roll back snapshot modified original subvolume needs unmounted snapshot needs mounted place point original subvolume may also deleted copy-on-write cow nature btrfs means snapshots quickly created initially consuming little disk space since snapshot subvolume creating nested snapshots also possible taking snapshots subvolume recursive process thus snapshot subvolume created every subvolume snapshot subvolume already contains mapped empty directory name inside snapshot taking snapshots directory possible subvolumes snapshots however workaround involves reflinks spread across subvolumes new subvolume created containing cross-subvolume reflinks content targeted directory available snapshot new volume created subvolume btrfs quite different traditional logical volume manager lvm logical volume lvm logical volume separate block device btrfs subvolume treated used way making dd lvm snapshots btrfs leads dataloss either original copy mounted computer given pair subvolumes snapshots btrfs generate binary diff using codice_7 command replayed later using codice_8 possibly different btrfs file system send–receive feature effectively creates applies set data modifications required converting one subvolume another send/receive feature used regularly scheduled snapshots implementing simple form file system master–slave replication purpose performing incremental backups quota group qgroup imposes upper limit space subvolume snapshot may consume new snapshot initially consumes quota data shared parent thereafter incurs charge new files copy-on-write operations existing files quotas active quota group automatically created new subvolume snapshot initial quota groups building blocks grouped codice_9 command hierarchies implement quota pools quota groups apply subvolumes snapshots quotas enforced individual subdirectories users user groups possible however workarounds possible using different subvolumes users user groups require quota enforced result little metadata anchored fixed locations btrfs warp fit unusual spatial layouts backend storage devices codice_10 tool exploits ability in-place conversion ext2/3/4 reiserfs file system nesting equivalent btrfs metadata unallocated space—while preserving unmodified copy original file system conversion involves creating copy whole ext2/3/4 metadata btrfs files simply point blocks used ext2/3/4 files makes bulk blocks shared two filesystems conversion becomes permanent thanks copy-on-write nature btrfs original versions file data blocks preserved file modifications conversion becomes permanent blocks marked free ext2/3/4 used hold new btrfs modifications meaning conversion undone time although erase changes made conversion btrfs converted files available writable default subvolume btrfs sparse file holding references original ext2/3/4 filesystem created separate subvolume mountable read-only disk image allowing original converted file systems accessed time deleting sparse file frees space makes conversion permanent june 2015 4.x versions linux kernel mainline in-place ext3/4 conversion considered untested rarely used feature however rewritten scratch 2016 codice_11 4.6. considered stable since in-place conversion reiserfs introduced september 2017 kernel 4.13 creating new btrfs existing btrfs used read-only seed file system new file system act copy-on-write overlay seed form union mounting seed later detached btrfs point rebalancer simply copy seed data still referenced new file system detaching mason suggested may useful live cd installer might boot read-only btrfs seed optical disc rebalance target partition install disk background user continues work eject disc complete installation without rebooting 2009 interview chris mason stated support encryption planned btrfs meantime workaround combining encryption btrfs use full-disk encryption mechanism dm-crypt luks underlying devices create btrfs filesystem top layer unix systems traditionally rely fsck programs check repair filesystems functionality implemented via codice_12 program since version 4.0 functionality deemed relatively stable however august 2017 btrfs documentation suggests used tried recovery methods another tool named codice_13 used recover files unmountable filesystem without modifying broken filesystem i.e. non-destructively normal use btrfs mostly self-healing recover broken root trees mount time thanks making periodic data flushes permanent storage default every 30 seconds thus isolated errors cause maximum 30 seconds filesystem changes lost next mount period changed specifying desired value seconds codice_14 mount option ohad rodeh original proposal usenix 2007 noted b+ trees widely used on-disk data structures databases could efficiently allow copy-on-write-based snapshots leaf nodes linked together leaf copy-on-written siblings parents would well would siblings parents entire tree copied suggested instead modified b-tree leaf linkage refcount associated tree node stored ad-hoc free map structure certain relaxations tree balancing algorithms make copy-on-write friendly result would data structure suitable high-performance object store could perform copy-on-write snapshots maintaining good concurrency oracle later year chris mason began work snapshot-capable file system would use data structure almost exclusively—not metadata file data also recursively track space allocation trees allowed traversal modifications funneled single code path features copy-on-write checksumming mirroring needed implemented benefit entire file system btrfs structured several layers trees using b-tree implementation trees store generic items sorted 136-bit key first 64 bits key unique object id middle 8 bits item type field use hardwired code item filter tree lookups objects multiple items multiple types remaining right-hand 64 bits used type-specific ways therefore items object end adjacent tree ordered type choosing certain right-hand key values objects put items type particular order interior tree nodes simply flat lists key-pointer pairs pointer logical block number child node leaf nodes contain item keys packed front node item data packed end two growing toward leaf fills every tree appears object root tree tree tree roots trees file system trees log trees variable number instances given object id trees singletons data relocation extent chunk trees assigned special fixed object ids ≤256 root tree appears tree object id 1 trees refer object id may also refer individual nodes trees triplet tree object id node level within tree leftmost key value references independent tree actually stored user-visible files directories contained file system tree one file system tree per subvolume subvolumes nest case appear directory item described whose data reference nested subvolume file system tree within file system tree file directory object inode item extended attributes acl entries stored alongside separate items within directory directory entries appear directory items whose right-hand key values crc32c hash filename data location key key inode item points directory items together thus act index path-to-inode lookups used iteration sorted hash effectively randomly permuting means user applications iterating opening files large directory would thus generate many disk seeks non-adjacent files—a notable performance drain file systems hash-ordered directories reiserfs ext3 htree-indexes enabled ext4 tea-hashed filenames avoid directory entry directory index item whose right-hand key value item set per-directory counter increments new directory entry iteration index items thus returns entries roughly order stored disk besides inode items files directories also reference item whose right-hand key value object id parent directory data part reference item filename inode known directory allows upward traversal directory hierarchy providing way map inodes back paths files hard links multiple directories multiple reference items one parent directory files multiple hard links directory pack links filenames reference item design flaw limited number same-directory hard links however many could fit single tree block default block size 4 kib average filename length 8 bytes per-filename header 4 bytes would less 350 applications made heavy use multiple same-directory hard links git gnus gmame backuppc later observed fail hitting limit limit eventually removed october 2012 merged pending release linux 3.7 introducing spillover extended reference items hold hard link filenames could otherwise fit file data kept outside tree extents contiguous runs disk blocks extent blocks default 4kib size headers contain possibly compressed file data compressed extents individual blocks compressed separately rather compression stream spans entire extent files extent data items track extents hold contents item right-hand key value starting byte offset extent makes efficient seeks large files many extents correct extent given file offset computed one tree lookup snapshots cloned files share extents small part large extent overwritten resulting copy-on-write may create three new extents small one containing overwritten data two large ones unmodified data either side overwrite avoid re-write unmodified data copy-on-write may instead create bookend extents extents simply slices existing extents extent data items allow including offset extent tracking items bookends non-zero offsets file data small enough fit inside tree node instead pulled in-tree stored inline extent data item tree node stored tree block —a single uncompressed block header tree block regarded free-standing single-block extent extent allocation tree acts allocation map file system unlike trees items tree object ids represent regions space left-hand right-hand key values starting offsets lengths regions represent file system zones allocated space block groups variable-sized allocation regions alternate successively preferring metadata extents tree nodes data extents file contents default ratio data metadata block groups 1:2 intended work like orlov block allocator block groups ext3 allocating related files together resisting fragmentation leaving allocation gaps groups ext3 block groups however fixed locations computed size file system whereas btrfs dynamic created needed block group associated block group item inode items file system tree include reference current block group extent items contain back-reference tree node file occupying extent may multiple back-references extent shared snapshots many back-references fit item spill individual extent data reference items tree nodes turn back-references containing trees makes possible find extents tree nodes region space b-tree range lookup pair offsets bracketing region following back-references relocating data allows efficient upwards traversal relocated blocks quickly find fix downwards references blocks without walk entire file system turn allows file system efficiently shrink migrate defragment storage online extent allocation tree trees file system copy-on-write writes file system may thus cause cascade whereby changed tree nodes file data result new extents allocated causing extent tree change avoid creating feedback loop extent tree nodes still memory yet committed disk may updated in-place reflect new copy-on-written extents theory extent allocation tree makes conventional free-space bitmap unnecessary extent allocation tree acts b-tree version bsp tree practice however in-memory red-black tree page-sized bitmaps used speed allocations bitmaps persisted disk starting linux 2.6.37 via codice_15 mount option special extents exempt checksumming copy-on-write extent items tracking extents stored root tree crc-32c checksums computed data metadata stored checksum items checksum tree room 256 bits metadata checksums full leaf block roughly 4 kb data checksums checksum algorithm options planned future one checksum item per contiguous run allocated blocks per-block checksums packed end-to-end item data checksums fit spill rightwards another checksum item new leaf file system detects checksum mismatch reading block first tries obtain create good copy block another device internal mirroring raid techniques use btrfs initiate online check entire file system triggering file system scrub job performed background scrub job scans entire file system integrity automatically attempts report repair bad blocks finds along way fsync request commit modified data immediately stable storage fsync-heavy workloads like database virtual machine whose running os fsyncs intensively could potentially generate great deal redundant write i/o forcing file system repeatedly copy-on-write flush frequently modified parts trees storage avoid temporary per-subvolume log tree created journal fsync-triggered copy-on-writes log trees self-contained tracking extents keeping checksum items items replayed deleted next full tree commit system crash next remount block devices divided physical chunks 256 mb physical chunks across multiple devices mirrored striped together single logical chunk logical chunks combined single logical address space rest filesystem uses chunk tree tracks storing device therein device item logical chunks chunk map items provide forward mapping logical physical addresses storing offsets right-hand 64 bits key chunk map items one several different types n however many block devices still free space chunk allocated n large enough chosen mirroring/mapping filesystem effectively space device tree inverse chunk tree device extent items provide reverse mapping byte-ranges block devices back logical chunks storing device number left hand 64-bits physical offset right-hand 64 bits key two trees together allow btrfs grow shrink even change raid levels without unmounting make possible efficiently locate chunks affected shrink/move operations relocate contents on-the-fly file system chunks devices assigned universally unique identifier uuid header every tree node contains uuid containing chunk uuid file system chunk device trees refer devices chunks uuids filesystems single block device dup also default profile metadata intended improve odds successful data salvage event media errors defragmentation shrinking rebalancing operations require extents relocated however simple copy-on-write relocating extent break sharing snapshots consume disk space preserve sharing update-and-swap algorithm used special relocation tree serving scratch space affected metadata extent relocated first copied destination following backreferences upward affected subvolume file system tree metadata pointing old extent progressively updated point new one newly updated items stored relocation tree update complete items relocation tree swapped counterparts affected subvolume relocation tree discarded file system trees—including chunk tree itself—are stored chunks creating potential bootstrapping problem mounting file system bootstrap mount list physical addresses chunks belonging chunk root trees must stored superblock superblock mirrors kept fixed locations 64 kib every block device additional copies 64 mib 256 gib 1 pib superblock mirror updated generation number incremented mount time copy highest generation number used superblock mirrors updated tandem except ssd mode alternates updates among mirrors provide wear levelling
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Computer file systems
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undefined behavior computer programming undefined behavior ub result executing computer code whose behavior prescribed language specification code adheres current state program happens translator source code makes certain assumptions assumptions satisfied execution behavior programming languages—most famously c c++—is undefined cases standards languages semantics certain operations described undefined cases typically represent unambiguous bugs code example indexing array outside bounds implementation allowed assume operations never occur correct standard-conforming program code case c/c++ compiler allowed give compile-time diagnostic cases required implementation considered correct whatever cases analogous don't-care terms digital logic responsibility programmer write code never invokes undefined behavior although compiler implementations allowed issue diagnostics happens assumption make various program transformations valid simplify proof correctness giving flexibility implementation result compiler often make optimizations also allows compile-time checks compilers static program analysis c community undefined behavior may humorously referred nasal demons comp.std.c post explained undefined behavior allowing compiler anything chooses even make demons fly nose circumstances specific restrictions undefined behavior example instruction set specifications cpu might leave behavior forms instruction undefined cpu supports memory protection specification probably include blanket rule stating user-accessible instruction may cause hole operating system security actual cpu would permitted corrupt user registers response instruction would allowed example switch supervisor mode documenting operation undefined behavior allows compilers assume operation never happen conforming program gives compiler information code information lead optimization opportunities example c language value codice_1 negative given signed integer overflow undefined behavior c compiler assume codice_2 always false thus codice_3 statement including call function codice_4 ignored compiler since test expression codice_3 side effects condition never satisfied code therefore semantically equivalent compiler forced assume signed integer overflow wraparound behavior transformation would legal optimizations become hard spot humans code complex optimizations like inlining take place another benefit allowing signed integer overflow undefined makes possible store manipulate variable value processor register larger size variable source code example type variable specified source code narrower native register width int 64-bit machine common scenario compiler safely use signed 64-bit integer variable machine code produces without changing defined behavior code program depended behavior 32-bit integer overflow compiler would insert additional logic compiling 64-bit machine overflow behavior machine instructions depends register width important benefit undefined signed integer overflow enables though require erroneous overflows detected compile-time static program analysis run-time checks clang gcc sanitizers valgrind overflow defined semantics wrap-around compile-time checks would possible c c++ standards several forms undefined behavior throughout offer increased liberty compiler implementations compile-time checks expense undefined run-time behavior present particular iso c standard appendix listing common sources undefined behavior moreover compilers required diagnose code relies undefined behavior hence common programmers even experienced ones rely undefined behavior either mistake simply well-versed rules language span hundreds pages result bugs exposed different compiler different settings used testing fuzzing dynamic undefined behavior checks enabled e.g clang sanitizers help catch undefined behavior diagnosed compiler static analyzers scenarios security critical undefined behavior lead security vulnerabilities software gcc developers changed compiler 2008 omitted certain overflow checks relied undefined behavior cert issued warning newer versions compiler linux weekly news pointed behavior observed pathscale c microsoft visual c++ 2005 several compilers warning later amended warn various compilers major forms undefined behavior c broadly classified spatial memory safety violations temporal memory safety violations integer overflow strict aliasing violations alignment violations unsequenced modifications data races loops neither perform i/o terminate c use automatic variable initialized yields undefined behavior integer division zero signed integer overflow indexing array outside defined bounds see buffer overflow null pointer dereferencing general instance undefined behavior leaves abstract execution machine unknown state causes behavior entire program undefined attempting modify string literal causes undefined behavior ref name= c++03 2.13.4/2 iso/iec 2003 iso/iec 14882:2003 e programming languages c++ §2.13.4 string literals lex.string para 2 /ref integer division zero results undefined behavior ref name= c++03 5.6/4 iso/iec 2003 iso/iec 14882:2003 e programming languages c++ §5.6 multiplicative operators expr.mul para 4 /ref certain pointer operations may result undefined behavior ref name= c++03 5.6/5 iso/iec 2003 iso/iec 14882:2003 e programming languages c++ §5.7 additive operators expr.add para 5 /ref c c++ comparison pointers objects strictly defined pointers point members object elements array. ref name= c++03 5.9/2 iso/iec 2003 iso/iec 14882:2003 e programming languages c++ §5.9 relational operators expr.rel para 2 /ref example reaching end value-returning function main without return statement results undefined behavior value function call used caller ref name= c99 6.9.1/12 iso/iec 2007 iso/iec 9899:2007 e programming languages c §6.9 external definitions para 1 /ref modifying object two sequence points produces undefined behavior considerable changes causes undefined behavior relation sequence points c++11 following example however cause undefined behavior c++ c. modifying object two sequence points reading value object purpose determining value stored also undefined behavior. ref name= c99 6.5/2 iso/iec 1999 iso/iec 9899:1999 e programming languages c §6.5 expressions para 2 /ref c/c++ bitwise shifting value number bits either negative number greater equal total number bits value results undefined behavior safest way regardless compiler vendor always keep number bits shift right operand « » bitwise operators within range codice_6
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Programming language topics
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apple dos apple dos family disk operating systems apple ii series microcomputers late 1978 early 1983 superseded prodos 1983 apple dos three major releases dos 3.1 dos 3.2 dos 3.3 one three releases followed second minor bug-fix release case apple dos 3.2 minor release receive version number apple dos 3.2.1 best-known most-used version apple dos 3.3 1980 1983 releases prior release apple dos 3.1 apple users rely audio cassette tapes data storage retrieval apple computer introduced apple ii april 1977 new computer disk drive disk operating system dos although apple co-founder steve wozniak designed disk ii controller late year believed could written dos co-founder steve jobs decided outsource task company considered using digital research cp/m wozniak sought operating system easier use 10 april 1978 apple signed 13,000 contract shepardson microsystems write dos deliver within 35 days apple provided detailed specifications early apple employee randy wigginton worked closely shepardson paul laughton latter wrote operating system punched cards minicomputer apple dos 1 2 versions 0.1 2.8 serially enumerated revisions development might well called builds 1 28 apple dos 3.0 renamed issue version 2.8 never publicly released due bugs apple published official documentation release 3.2 apple dos 3.1 publicly released june 1978 slightly one year apple ii introduced becoming first disk-based operating system apple computer bug-fix release came later addressing problem means utility used create apple dos master bootable disks built-in command created disks could booted machines least amount memory one created includes self-relocating version dos boots apples memory configuration apple dos 3.2 released 1979 reflect changes computer booting methods built successor apple ii apple ii plus new firmware included auto-start feature automatically found disk controller booted system powered up—earning name autostart rom apple dos 3.3 released 1980 improves various functions release 3.2 also allowing large gains available floppy disk storage newer p5a/p6a proms disk controller enabled reading writing data higher density instead 13 sectors 3.25 kib 16 sectors 4 kib data stored per disk track increasing capacity 113.75 kb 140 kb per disk side 16 kb used filesystem overhead copy dos dos 3.3-formatted disk leaving 124 kb user programs data dos 3.3 however backward compatible read write dos 3.2 disks address problem apple computer released utility called muffin migrate apple dos 3.2 files programs version 3.3 disks apple never offered utility copy way migrate apple dos 3.3 files back version 3.2 disks someone wrote niffum utility also commercial utilities copy ii plus copy files either format eventually prodos well release 3.3 also improves ability switch integer basic applesoft basic computer language card ram expansion firmware card apple dos 3.1 disks use 13 sectors data per track sector 256 b uses 35 tracks per disk side access one side floppy disk unless user flipped disk gives user total storage capacity 113.75 kb per side 10 kb used store dos disk directory leaving 100 kb user programs first layer operating system called rwts stands read/write track sector layer consists subroutines track seeking sector reading writing disk formatting api called file manager built top implements functions open close read write delete lock i.e write-protect unlock i.e write-enable rename files verify file structural integrity also catalog function listing files diskette init function formats disk use dos storing copy dos first three tracks storing startup program usually called hello auto-started disk booted top file manager api main dos routines implemented hook machine basic interpreter intercept disk commands provides bload bsave brun storing loading running binary executables load run save provided basic programs exec provided running text-based batch files consisting basic dos commands finally four types files exist identified letters catalog listing four additional file types r additional b none fully supported dos recognizes types catalog listings direct ways manipulate types files r type found use relocatable binary executable files programs support type data files call vector table region 03d0–03ff allows programs find dos wherever loaded system memory example dos hooked basic cli stops functioning reinitialized calling location 03d0 976 hence traditional 3d0g 3d0 go command return basic system monitor process loading apple dos involves series tiny programs carries loading process forward steps passing control next program chain original apple ii included basic interpreter rom known originally apple basic later integer basic variables language handle integer numbers ranging −32,768 +32,767 16-bit binary values floating point numbers supported apple commissioned microsoft develop applesoft basic capable handling floating-point numbers applesoft basic run integer basic programs causing users resist upgrading dos 3.3 released applesoft basic standard rom apple ii plus apple designed support switching back forth two basic interpreters integer basic loaded ram language card apple iis present typing fp int basic user switch either version 1980 apple dos entered state stagnation apple concentrated efforts ill-fated apple iii computer sos operating system two versions apple dos still called dos 3.3 bug fixes better support new apple iie model released early mid-1983 without third-party patches apple dos read floppy disks running 5.25-inch disk ii drive access media hard disk drives virtual ram drives 3.5-inch floppy disk drives structure apple dos disks particularly free sector map restricted part single sector possible 400 kb available time per drive without major rewrite almost sections code main reason apple abandoned iteration dos 1983 apple dos entirely replaced prodos prodos retains 16-sector low-level format dos 3.3 5.25 inch disks introduces new high-level format suitable devices 32 mb makes suitable hard disks era 3.5-inch floppies apple computers ii plus onward run dos 3.3 prodos plus requiring language card memory expansion use prodos e later models built-in language card hardware run prodos straight prodos includes software copy files apple dos disks however many people need improvements prodos like much higher memory footprint continued using apple dos one clones long 1983 apple convention storing bootable os every single floppy disk means commercial software used matter os user owns program called dos.master enables users multiple virtual dos 3.3 partitions larger prodos volume allows use many floppy-based dos programs hard disk shortly prodos came apple withdrew permission third parties redistribute dos 3.3 granted one company syndicomm exclusive license resell dos 3.3 commercial games usually use apple dos instead custom disk routines copy protection purposes well performance dos rwts routine read write track two revolutions proper interleaving sector spinning disk passes read/write head rwts routine decoding just-read sector encoding next one written missed sector next one needed dos needs wait nearly entire revolution disk sector come around called blowing rev well-understood performance bottleneck disk systems avoid sectors dos disk arranged interleaved order later prodos arranged sectors order reading decoding sector 0 sector 8 passes sector 1 next sector likely needed available without waiting reading sector 7 two unneeded sectors f 0 pass sector 8 available reading sector 15 drive always wait extra revolution sector 0 track however sector 0 actually needed cases next-higher track track arranged relative last one allow needed time decode just-read sector move head sector 0 comes around average full track read two revolutions disk unfortunately early dos file manager subverted efficiency copying bytes read written file one time disk buffer main memory requiring time resulting dos constantly blowing revs reading writing files programs became available early format disks modified sector interleaves disks give dos time sectors copy data ameliorating problem later programmers outside apple rewrote file manager routines avoid making extra copy sectors file rwts instructed read write sectors directly main memory rather disk buffer whenever full sector transferred early patch provide functionality published call-a.p.p.l.e. speedups load command three five times typical functionality soon appeared commercial products pronto-dos diversi-dos hyper-dos david-dos along additional features never used official apple dos release similar functionality however employed apple successor operating system prodos apple iigs-specific operating system gs/os would eventually employ even efficient scatter read technique would read sector happened passing read head needed file read 2013 35 years apple ii debuted original apple dos source code released computer history museum website donated original author paul laughton
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Operating systems
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free-form language computer programming free-form language programming language positioning characters page program text insignificant program text need placed specific columns old punched card systems frequently ends lines insignificant whitespace characters used delimit tokens significance free-form languages descend algol including c pascal perl lisp languages free-form although descend algol rexx mostly free-form though cases whitespace characters concatenation operators sql though full programming language also free-form free-form languages also structured programming languages sometimes thought go along free-form syntax earlier imperative programming languages fortran 77 used particular columns line numbers many structured languages use need structured languages exist free-form abc curry haskell python others many use variant off-side rule indentation rather keywords braces used group blocks code
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Programming language topics
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palm os emulator descended copilot palm os emulator used writing testing debugging palm os applications palm os emulator emulates motorola 68000-class devices intimate knowledge palm os inner working allowing close monitoring correct application operation unlike xcopilot another descendant copilot palm os emulator boot uclinux using skin files palm os emulator could closely mimic appearance many models palm handheld versions palm os emulator require file containing rom image boot rom image files obtained palmsource part access co. ltd downloaded real palm device palm os emulator supported palm models produced palm handera handspring symbol palm os handhelds produced sony clie line supported separate sony-specific fork palm os emulator copilot palm os emulator released gpl v2 versions developed palm inc. windows macintosh unix platforms sony fork released windows palm os emulator supports palm os 4.x earlier support palm os 5.x later versions based arm processor palmsource provides simulators palm os 5.x palm os recompiled run natively windows linux mac windows versions emulator included cd-rom included palm programming developer guide published o'reilly 1999
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Computer architecture
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semantic p2p networks semantic p2p networks new type p2p network combines advantages unstructured p2p networks structural p2p networks avoids disadvantages semantic p2p networks nodes classified dns-like domain names semantic meanings alice brittney.popular.music semantic p2p networks contains prerequisite virtual tree topology net-like topology formed cached nodes semantic p2p networks keep semantic meanings nodes contents nodes within semantic p2p networks communicate various languages semantic p2p network execute complicated queries sql-like language similarities semantic p2p systems software agents p2p means entities exchange information directly without mediator semantic concept add meaning information peer usually autonomous systems well agents agents follow goal though goal attainment requires knowledge base rules strategies major difference software agents semantic peers latter lacks kind intelligence
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Distributed computing architecture
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mg editor mg originally called micrognuemacs later changed request richard stallman public-domain text editor runs unix-like operating systems based microemacs intended closely resemble gnu emacs still maintaining small memory footprint fast speed expanded version original included part openbsd maintained snapshots openbsd version available native package management trees many systems including macports freebsd ports pkgsrc debian
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Operating systems
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2016 dyn cyberattack 2016 dyn cyberattack series distributed denial-of-service attacks ddos attacks october 21 2016 targeting systems operated domain name system dns provider dyn attack caused major internet platforms services unavailable large swathes users europe north america groups anonymous new world hackers claimed responsibility attack scant evidence provided dns provider dyn provides end-users service mapping internet domain name—when instance entered web browser—to corresponding ip address distributed denial-of-service ddos attack accomplished large number dns lookup requests tens millions ip addresses activities believed executed botnet consisting large number internet-connected devices—such printers ip cameras residential gateways baby monitors—that infected mirai malware according dyn distributed denial-of-service ddos attack began 7:00 a.m. edt resolved 9:20 a.m. second attack reported 11:52 a.m. internet users began reporting difficulties accessing websites third attack began afternoon 4:00 p.m. 6:11 p.m. dyn reported resolved issue dyn chief strategy officer spokesperson kyle york led communication response customers partners market services affected attack included us department homeland security started investigation attacks according white house source group hackers claimed responsibility immediate aftermath attack dyn chief strategist said interview assaults company servers complex unlike everyday ddos attacks barbara simons member advisory board united states election assistance commission said attacks could affect electronic voting overseas military civilians dyn disclosed according business risk intelligence firm flashpoint akamai technologies attack botnet coordinated large number internet things-enabled iot devices including cameras residential gateways baby monitors infected mirai malware attribution attack mirai botnet previously reported backconnect inc. another security firm dyn stated receiving malicious requests tens millions ip addresses mirai designed brute-force security iot device allowing controlled remotely cybersecurity investigator brian krebs noted source code mirai released onto internet open-source manner weeks prior make investigation perpetrator difficult 25 october 2016 us president obama stated investigators still idea carried cyberattack 13 december 2017 justice department announced three men paras jha 21 josiah white 20 dalton norman 21 entered guilty pleas cybercrime cases relating mirai clickfraud botnets correspondence website politico hacktivist groups spainsquad anonymous new world hackers claimed responsibility attack retaliation ecuador rescinding internet access wikileaks founder julian assange embassy london granted asylum claim yet confirmed wikileaks alluded attack twitter tweeting mr. assange still alive wikileaks still publishing ask supporters stop taking us internet proved point new world hackers claimed responsibility past similar attacks targeting sites like bbc espn.com october 26 flashpoint stated attack likely done script kiddies november 17 2016 forbes article reported attack likely carried angry gamer
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Computer security
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clive finkelstein clive finkelstein born ca 1939 australian computer scientist known father information technology engineering 1961 finkelstein received bachelor science university new south wales sydney graduation finkelstein started working field database processing ibm australia usa back australia 1976 founded consultancy firm infocom australia 1972 finkelstein elected fellow australian computer society finkelstein distinguished member international advisory board dama international data administration management association john zachman 2008 awarded position pearcey hall fame acs australia 1976 1980 finkelstein developed concept information technology engineering based original work carried bridge strategic business planning information systems wrote first publication information technology engineering series six in-depth articles name published us computerworld may june 1981 also co-authored james martin influential savant institute report titled information engineering published nov 1981 also wrote monthly column enterprise dm review magazine
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Databases
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adodb adodb database abstraction library php originally based concept microsoft activex data objects allows developers write applications consistent way regardless underlying database system storing information advantage database system changed without re-writing every call application adodb supports following databases addition database abstraction layer adodb includes following features
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Databases
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code breaker code breaker cheat device developed pelican accessories currently available playstation playstation 2 dreamcast game boy advance nintendo ds along competing product action replay one currently supported video game cheat devices originally developed fire international group distributed pelican accessories ntsc/uc north american counterpart pal european xploder cheat device codebreaker first appeared dreamcast relatively late console lifecycle soon dreamcast version released development began playstation 2 version version six hit market fire international abruptly broke partnership pelican develop newly mad catz-acquired gameshark also time game boy advance code breaker discontinued pelican accessories put together internal development team proceeded future versions codebreaker original site www.codebreaker.com codetwink bought new site day1 feature allows get codes online import codebreaker usb flash drive codes removed codetwink brought back though previous versions playstation 2 code breaker plagued limited functionality later versions lauded features simple uncluttered menu typing systems version 9 added support usb keyboards unlike cheat devices store cheat codes proprietary storage devices playstation 2 code breaker stores codes memory cards thus cutting manufacturing costs saves also copied usb flash drives device official web site codetwink run codemasterx also coded entire cheat engine cheat code types product provides codes posted former game shark code creators club codes downloaded official web site using device day1 feature later versions include support playstation 2 broadband adapter internet chat using code breaker device one access feature named day1 import/export saves cases one avoid typing number number using cheats import however pelican accessories longer supports since latest version codebreaker codebreaker 10.1 www.codebreaker.com set codebreaker site device longer connect internet get codes use codebreaker chat site change code breaker discontinued may 2012 www.codetwink.com uses vbulletin type site format still codebreaker day1 files available download people register account june 2013 day1 files unavailable codetwink.com server moved hard drive damaged april 2017 mirror old codetwink site hosted wes castro developer cheat device project codemasterx also returned hosting maintaining modern codetwink site also sells game genie game save editor playstation 3 consoles
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Computer architecture
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ipod touch 5th generation fifth-generation ipod touch stylized marketed ipod touch colloquially known ipod touch 5g ipod touch 5 unveiled apple media event alongside iphone 5 september 12 2012 released october 11 2012 all-purpose pocket computer designed marketed apple inc. touchscreen-based user interface succeeded 4th-generation ipod touch compatible ios 9.3.5 released august 25 2016 like iphone 5 fifth-generation ipod touch slimmer lighter model introduces higher-resolution 4-inch screen series widescreen aspect ratio improvements include support recording 1080p video panoramic still photos via rear camera led flash apple a5 chip chip used ipad mini 1st generation ipad 2 iphone 4s support apple siri additionally unlike predecessors fifth-generation ipod touch initially featured slate silver pink yellow blue product red back colors however release iphone 5s slate color changed space gray colors remained unchanged device initially sold 32 gb 64 gb models first 16 gb model introduced may 30 2013 available one color lacks rear isight camera ipod touch loop included 32 gb models june 26 2014 replaced new 16 gb model longer omits rear camera full range color options pricing ipod touch also changed 16 gb model 199 instead 229 32 gb model 249 instead 299 64 gb model 299 instead 399 ipod touch 5th generation officially discontinued apple july 15 2015 release successor ipod touch 6th generation however apple still continues sell refurbished models fifth generation ipod touch features ios apple mobile operating system user interface ios based concept direct manipulation using multi-touch gestures interface control elements consist sliders switches buttons interaction os includes gestures swipe tap pinch reverse pinch specific definitions within context ios operating system multi-touch interface internal accelerometers used applications respond shaking device one common result undo command rotating vertically one common result switching portrait landscape mode initially shipped ios 6 released september 19 2012 play music movies television shows ebooks audiobooks podcasts sort media library songs artists albums videos playlists genres composers podcasts audiobooks compilations users rotate device horizontally landscape mode access cover flow feature shows different album covers scroll-through photo library scrolling achieved swiping finger across screen alternatively headset controls used pause play skip repeat tracks however earpods comes ipod include remote mic voice control feature also used identify track play songs playlist specific artist create genius playlist like iphone 4s later models fifth generation ipod touch first ipod touch line-up include siri allows user operate device spoken commands software improved ios 6 include ability make restaurant reservations launch apps dictate facebook twitter updates retrieve movie reviews detailed sports statistics typing aided voice assistant converts speech text also supports imessage specialised instant messaging program service allows unlimited texting apple devices running ios 5 later newer applications features came ios 6 included apple maps passbook screen mirroring apple maps replaced former map application powered google maps lacks many features present competing maps apps also known give wrong directions users still fixed ios 7 updates new apple maps app uses apple new vector-based engine eliminates lag making smoother zooming new maps turn-by-turn navigation spoken directions 3d views major cities real-time traffic new passbook app able retrieve documents boarding passes admission tickets coupons loyalty cards ios device passbook scanned reader process mobile payment locations compatible hardware airplay made available allows screen mirroring apple tv supported external device allows screen ipod touch mirrored first generation ipod touch support ios 7 released september 18 2013 ios devices generation ipod touch ipod touch line-up run ios 7 june 2 2014 announced ipod touch 5th generation would receive ios 8 fall released september 17 2014 confirmed june 8 2015 apple wwdc ipod touch 5th generation would support ios 9 makes first ipod touch support 4 major versions ios ios 6 ios 7 ios 8 ios 9. ios 9 said apple feature performance improvements may help aging device function smoothly a5-based devices also support ios 9 including ipad 2 6 major ios versions iphone 4s 5 major ios versions ipad mini 4 major ios versions ios 9.3.5 last update supports ipod touch 5th generation receive ios 10 along iphone 4s ipad 2 3 ipad mini 1st generation due hardware limitations fifth generation ipod touch features apple a5 chip similar one iphone 4s ipad 2 ipad mini chip comprises 1 ghz dual core arm cortex-a9 processor powervr sgx543mp2 2-core gpu making faster fourth generation ipod touch uses apple a4 chip storage capacities available 32 64 gb 16 gb announced later date replace previous generation retina display ipod similar one iphone 5 measuring 1,136 640 pixels aspect ratio almost exactly 16:9 measuring 4 inches diagonally display size 6.7 square inches pixel density 326 ppi remains fourth generation screen icons arranged matrix 6 rows 4 icons larger screen previous generation model fifth generation ipod touch allows 6th row icons added 5 rows present fourth generation ipod touch however fifth generation ipod touch include ambient light sensor included previous generation new isight camera 5 megapixels capable 1080p video recording illuminated sensor led flash front-facing camera also upgraded 1.2 megapixels capable 720p video compared vga 0.3 megapixels front camera fourth generation fifth-generation ipod touch finish features aluminum unibody made kind anodized aluminium used macbook line new isight camera led flash ipod touch includes new feature known ipod touch loop bottom left corner back ipod touch button pressed allow wrist strap attach ipod touch changes ipod touch include addition colors available five space grey replacing slate color variant september 2013 silver pink yellow blue product red space grey slate version comes black front rest color variants ipod come white front fifth-generation ipod touch initially released 32 gb 64 gb models 16 gb version include isight camera led flash loop released may 30 2013 model replaced 16 gb model original design june 26 2014 fifth generation ipod touch well iphone 5 ipod nano 7th generation ipad 4th generation ipad mini feature new dock connector named lightning replacing 30-pin apple dock connector first introduced apple 2003 third generation ipod apple lightning connector eight pins signaling digital new connector also inserted either way unlike 30-pin connector inserted one way adapters released apple convert apple lightning connector older 30-pin apple dock connector usb although accessories work adapter signals available particular video output ipod feature bmw automobiles earphones known apple earpods also included fifth generation ipod touch devices announced apple media event september 12 2012 superseded earphones included previous generation iphones ipods according technology commentators redesign earphones aimed improve sound quality allowing air travel freely apple states redesign earphones allows rival high-end headphones cost hundreds dollars reviews gizmodo techradar reported although redesigned earphones sounded better predecessor reviewers felt quality sound produced still underwhelming stated earpods pale comparison earphones similar price accessories sold ipod touch include lanyard ipod touch loop available 16 gb model andrew williams trustedreviews noted 5th generation ipod touch common features iphone 5 praising design respectable connectivity graham barlow techradar commended improved screen color variants greater quality earphones ipod light weight criticizing reset lightning port scott stein cnet praised enhanced camera quality design remarked ipod touch still weaker outclassed compared ios devices
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Operating systems
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clavister br clavister swedish company specialized network security software listed nasdaq first north according report 451 research edward snowden nsa leaks consequent loss trust us-based products helped international expansion clavister clavister global presence customers japanese ntt-bp german marbach group clavister partnerships example japanese canon-its area virtualized network security nokia networks artesyn comparison firewalls
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Computer security
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backup sync share backup sync share bss emerging category products stems combination traditional data backup programs data synchronization mirroring applications data sharing applications many considerable expanding social media element
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Computer security
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compaq portable ii compaq portable ii third product compaq portable series brought compaq computer corporation released 1986 price us 3499 portable ii much improved upon predecessors included 8 mhz processor lighter smaller compaq portable four models compaq portable ii basic model 1 shipped one 5.25 floppy drive 256kb ram model 2 added second 5.25 floppy drive sold 3599 model 3 shipped 10mb hard disk addition one 5.25 floppy drive 640kb ram 4799 launch model 4 would upgrade model 3 20mb hard drive sold 4999 also may 4.1 mb hard drive included one point compaq portable ii significantly lighter predecessors model 1 weighed 23.6 pounds compared 30.5 pounds compaq portable 286 weighed compaq shipped system small demo disk ms-dos 3.1 purchased separately least two reported cases improperly serviced computers exploding non-rechargeable lithium battery motherboard connected power supply recorded injuries compaq portable ii succeeded compaq portable iii 1987 compaq portable ii room additional market upgrades compaq manufactured four memory expansion boards 512kb 2048kb isa memory cards 512kb 1536kb memory boards attached back motherboard 640kb installed motherboard isa card expansion board computer could upgraded maximum 4.2mb ram motherboard also space optional 80287 math coprocessor two revisions motherboard functionally identical although earlier version larger motherboard four isa slots expansion cards two 8-bit two 16-bit however first 16-bit slot already occupied cga graphics card one 8-bit slots used ata drive controller board leaving two available add cards keyboard hardwired uses standard ps/2 signaling din ps/2 socket retrofitted allow use common ps/2 keyboards usb ones
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Computer architecture
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solar designer alexander peslyak александр песляк born 1977 better known solar designer security specialist russia best known publications exploitation techniques including return-to-libc attack first generic heap-based buffer overflow exploitation technique well computer security protection techniques privilege separation daemon processes peslyak author widely popular password cracking tool john ripper code also used various third-party operating systems openbsd debian peslyak founder leader openwall project since 1999 founder openwall inc. cto since 2003 served advisory board member open source computer emergency response team ocert 2008 ocert conclusion august 2017 also co-founded oss-security spoken many international conferences including fosdem cansecwest wrote foreword michał zalewski 2005 book silence wire alexander received 2009 lifetime achievement award annual pwnie award black hat security conference 2015 qualys acknowledged help disclosure gnu c library codice_1 function buffer overflow cve-2015-0235
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Computer security
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sqlf sqlf sql extended fuzzy set theory application expressing flexible fuzzy queries traditional ″regular″ relational databases among known extensions proposed sql present time complete allows use diverse fuzzy elements constructions language sql sqlf known proposal flexible query system allowing linguistic quantification set rows queries achieved extension sql nesting partitioning structures fuzzy quantifiers also allows use quantifiers qualify quantity search criteria satisfied single rows several mechanisms proposed query evaluation important one based derivation principle consists deriving classic queries produce given threshold -cut result fuzzy query additional processing cost using fuzzy language diminished fundamental querying structure sqlf multi-relational block conception structure based three basic operations relational algebra projection cartesian product selection application fuzzy sets ’ concepts result sqlf query fuzzy set rows fuzzy relation instead regular relation basic block sqlf consists codice_1 clause codice_2 clause optional codice_3 clause semantic query structure following example codice_1 query returns list hotels cheap query retrieves rows hotels table satisfice fuzzy predicate cheap defined fuzzy set μ= 25 30 result sorted descending order membership degree query
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Databases
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waledac botnet waledac also known aliases waled waledpak botnet mostly involved e-mail spam malware march 2010 botnet taken microsoft eventual takedown waledac botnet consisted estimated 70,000-90,000 computers infected waledac computer worm botnet capable sending 1.5 billion spam messages day 1 total global spam volume february 25 2010 microsoft court order resulted temporary cut-off 277 domain names used command control servers botnet effectively crippling large part botnet however besides operating command control servers waledac worm also capable operating peer-to-peer communication various botnet nodes means extent damage difficult measure codenamed 'operation b49 investigation conducted months thereby yielded end 'zombie computers million 'zombie computers brought garrison hackers still infected early september 2010 microsoft granted ownership 277 domains used waledac broadcast spam email
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Computer security
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chinacache founded 1998 chinacache provider internet content application delivery services china 3-tier internet ecosystem chinacache also offers internet data center management internet exchange operations cloud hosting services chinacache network interconnected operated three dominating telecom carriers china mobile china unicom china telecom local internet service providers china company headquartered beijing china offices sunnyvale ca diamond bar ca london uk hong kong 2017 chinacache received national cdn license chinese government chinacache founded song wang 1998 2000 chinacache received cdn license china ministry industry information technology 2007 chinacache north america established serve global customers first office diamond bar ca followed research development center sunnyvale opened 2011 october 2010 chinacache filed ipo became listed nasdaq ticker symbol ccih 2013 atecsys data center operated chinacache established located beijing tianzhu free trade zone data center offers co-location services well ip peering internet exchange center chn-ix year chinacache opened office hong kong expanding service capacities apac 2015 chinacache opened office london uk chinacache maintains 500 service nodes 120 major cities globally across china network interconnected china telecom china netcom china mobile china unicom china railcom china cernet various access providers 2007 chinacache received 31.5 million investment intel capital ignition partners year also announced partnership rawflow provider live peer-to-peer streaming technologies 2008 chinacache partnered adobe systems offer flash video streaming service china 2008 chinacache announced support microsoft silverlight cross-platform cross-browser plug-in august 2011 chinacache announced partnership shanxi unicom wentian technology build shanxi largest cloud computing data center enable facilities including disaster recovery centers enterprise data centers internet data centers 2012 chinacache collaborated telecom malaysia hutchison global communications interxion expand services asia europe august 2013 chinacache collaborated microsoft corp. integrate company cdn services windows azure china service customers china august 2013 chinacache announced partnership kingsoft cloud group provide comprehensive suite cloud-based network services
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Distributed computing architecture
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security administrator tool analyzing networks security administrator tool analyzing networks satan free software vulnerability scanner analyzing networked computers satan captured attention broad technical audience appearing pc magazine drawing threats united states department justice featured web interface complete forms enter targets tables display results context-sensitive tutorials appeared vulnerability found offended name satan software contained special command called repent rearranged letters program acronym satan santa tool developed dan farmer wietse venema neil gaiman drew artwork satan documentation satan designed help systems administrators automate process testing systems known vulnerabilities exploited via network particularly useful networked systems multiple hosts like security tools useful good malicious purposes – also useful would-be intruders looking systems security holes satan written mostly perl utilized web browser netscape mosaic lynx provide user interface easy use interface drove scanning process presents results summary format well reporting presence vulnerabilities satan also gathered large amounts general network information hosts connected subnets types machines services offered satan fallen popularity height popularity 1990s satan released 1995 development ceased 2006 sectools.org conducted security popularity poll developed list 100 network security analysis tools order popularity based responses 3,243 people results suggest satan replaced nmap nessus lesser degree sara security auditor research assistant saint
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Computer security
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dynamic infrastructure dynamic infrastructure information technology paradigm concerning design data centers underlying hardware software respond dynamically changing levels demand fundamental efficient ways paradigm also known infrastructure 2.0 next generation data center vendors promoting dynamic infrastructures include ibm microsoft sun fujitsu hp dell bright computing basic premise dynamic infrastructures leverage pooled resources provide flexible capacity enabling allocation resources line demand business processes achieved using server virtualization technology pool computing resources wherever possible allocating resources on-demand using automated tools allows load balancing efficient approach keeping massive computing resources reserve run tasks take place example month otherwise under-utilized early examples server-level dynamic infrastructures flexframe sap flexframe oracle introduced fujitsu siemens computers fujitsu 2003 flexframe approach dynamically assign servers applications demand leveling peaks enabling organizations maximize benefit investments dynamic infrastructures may also used provide security data protection workloads moved migrations provisioning enhancing performance building co-location facilities dynamic infrastructures promoted enhance performance scalability system availability uptime increasing server utilization ability perform routine maintenance either physical virtual systems minimizing interruption business operations reducing cost dynamic infrastructures also provide fundamental business continuity high availability requirements facilitate cloud grid computing networking companies infrastructure 2.0 refers ability networks keep movement scale requirements new enterprise initiatives especially virtualization cloud computing according companies like cisco f5 networks infoblox network automation connectivity intelligence networks applications endpoints required reap full benefits virtualization many types cloud computing require network management infrastructure consolidated enabling higher levels dynamic control connectivity networks systems endpoints dynamic infrastructures take advantage intelligence gained across network design every dynamic infrastructure service-oriented focused supporting enabling end users highly responsive way utilize alternative sourcing approaches like cloud computing deliver new services agility speed global organizations already foundation dynamic infrastructure bring together business infrastructure create new possibilities example virtualized applications reduce cost testing packaging supporting application 60 reduced overall tco 5 7 model – source gartner – tco traditional software distribution vs application virtualization michael silver terrence cosgrove mark margevicious brian gammage 16 april 2008 green issues primary driver 10 current data center outsourcing hosting initiatives cost reductions initiatives driver 47 time aligned well green goals combining two means least 57 data center outsourcing hosting initiatives driven green – source gartner – green services catalyst cost optimization kurt potter 4 december 2008 2013 50 midsize organizations 75 large enterprises implement layered recovery architectures – source gartner – predicts 2009 business continuity management juggles standardization cost outsourcing risk roberta j witty john p morency dave russell donna scott rober desisto 28 january 2009
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Distributed computing architecture
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microsoft reserved partition microsoft reserved partition msr partition data storage device created simply reserve portion disk space possible subsequent use windows operating system installed separate partition meaningful data stored within msr though msr chunks may taken creation new partitions may contain data structures gpt label partition type codice_1 formerly disks formatted using older mbr partition layout certain software components used hidden sectors disk data storage purposes one example logical disk manager ldm disk converted basic disk dynamic disk would store metadata 1 mb area end disk allocated partition gpt formatted disks uefi partition specification allow hidden sectors microsoft reserves chunk disk space using msr partition type provide alternative data storage space software components previously may used hidden sectors mbr formatted disks software components example ldm mentioned create small software-component specific partition portion space reserved msr partition starting size msr depends disk size usually aligns following table size gets reduced portions msr taken used described beginning windows 10 minimum size msr 16 mb installer allocates default msr located efi system partition esp oem service partitions must located primary partitions bootable windows operating systems microsoft expects msr present every gpt disk recommends created disk initially partitioned chunks msr partition may also used remapping damaged sectors software device driver used temporary mirror critical operations core gpt structure emergency fast writing internal disk cache memory case power failure many disks fast write-through cache memory generally exceeding 32 mb msr created windows generally 128 mb default may larger systems fast recovery powering system contents msr generally data signature identify content make sure meaningful signature vendor-specific hardware component using normal operation system booted msr partition usually longer needed except device-specific power management systems may use msr also fast recoverable scratch area disk dynamically powered demand hardware raid managers msr may much smaller 1 2 mb start disk generally enough proper operation depending total disk size partition alignment parameters disks larger capacities 2 tb used servers may larger fast cache memory cache may backed frontal hidden ssd space needed msr area physical disk fast recovery case power failure using dynamic power management pcs preinstalled single ssd oem recovery partition usually end disk allows oem partition backed external dvd usb drive deleted ssd freeing space main data partition may extended free space old oem backup partition without move sectors ssd operation small msr partition may temporarily used scratch area recovery case unexpected failure conversion battery/power failure finally security tools may add data software components msr checking system integrity boot time uefi boot tools may also use msr temporary scratch area summary actual usage content msr device-specific invisible normal application software windows api msr partition exposed mountable volume contains standard filesystem msr partition visible within microsoft windows disk management control utility listed reserved microsoft diskpart command line utility bootable disks uefi systems msr partition generally second partition first small partition displayed system 100 mb containing fat32 filesystem store uefi boot data partitions actual main partition windows usually mounted volume c oses multiboot systems one several recovery partitions usually mounted visible microsoft windows disk management control utility oem system recovery partition usually located either end disk hard disks capacity 1tb near start disk msr partition large disks uefi-capable systems oem recovery partitions may also hidden microsoft windows disk management control utility using gpt partition attribute flag internal filesystem generally ntfs fat32 may mounted diskpart
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Computer file systems
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samsung galaxy original samsung gt-i7500 galaxy mobile phone manufactured samsung uses open source android operating system announced 27 april 2009 released 29 june 2009 first android-powered device samsung mobile first would become long galaxy series succeeded samsung i5700 galaxy spica galaxy smartphone offering quad-band gsm announced tri-band hsdpa 900/1700/2100 7.2mbit/s however samsung official pages danish finnish norwegian swedish versions mention dual-band umts 900/2100 phone features 3.2-inch amoled capacitive touchscreen 5 megapixel autofocus camera power led flash digital compass unlike first android phone htc dream g1 i7500 standard 3.5mm headphone jack directional pad place trackball software-wise galaxy offers suite mobile google services including google search gmail youtube google calendar google talk phone gps enables google maps features location google latitude also supports mp3 aac including itunes plus downloads codec .aac format h.264 video beta version spotify music streaming service also available phone via android marketplace due lack firmware updates samsung received criticism original galaxy users countries samsung updated galaxy firmware donut 1.6 users countries could download update manually risk warranty voiding
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Operating systems
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intel sha extensions intel sha extensions set extensions x86 instruction set architecture support hardware acceleration secure hash algorithm sha family introduced intel goldmont microarchitecture amd added support processors instructions starting ryzen seven new sse-based instructions four supporting sha-1 three sha-256
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Computer architecture
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udpcast udpcast file transfer tool send data simultaneously many destinations lan instance used install entire classrooms pcs advantage udpcast using methods nfs ftp whatever udpcast uses user datagram protocol multicast abilities wo n't take longer install 15 machines would install 2 default protocol operates udp port 9000 default behaviour changed boot stage http //udpcast.linux.lu/
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Computer security
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phoning home phoning home also called phone home call home computing refers act client server communication may undesirable user and/or proprietor device software often used refer behavior security systems report network location username data another computer phoning home may useful proprietor tracking missing stolen computer type phoning home frequently used mobile computers corporations typically involves software agent difficult detect remove however malicious types phoning home surreptitious communication applications hardware installed end-user sites manufacturers developers traffic may encrypted make difficult impractical end-user determine data transmitted stuxnet attack iran nuclear facilities facilitated phone home technology reported new york times uses phoning home practice legal countries example phoning home could purposes access restriction transmitting authorization key done adobe creative suite time one programs opened phones home serial number serial number listed already use fake program present user option inputting correct serial number user refuses next time program loads operate trial mode valid serial number input however method thwarted either disabling internet connection starting program adding firewall hosts file rule prevent program communicating verification server phoning home could also marketing purposes sony bmg rootkit transmits hash currently playing cd back sony digital video recorder dvr reporting viewing habits high-end computing systems mainframes 'phone home capabilities many years alert manufacturer hardware problems mainframes disk storage subsystems enables repair maintenance performed quickly even proactively maintenance contract similarly high-volume copy machines long equipped phone-home capabilities billing preventive/predictive maintenance purposes research computing phoning home used track daily usage open source academic software phoning used develop logs purposes justification grant proposals support ongoing funding projects aside malicious software phoning home phoning home may done track computer assets—especially mobile computers one well-known software applications leverages phoning home tracking absolute software computrace software employs agent calls absolute-managed server regular intervals information companies police use locate missing computer phoning home website applications authors applications allow documents thing thus allowing documents authors trigger essentially anonymous tracking setting connection intended logged behavior example caused v7.0.5 adobe reader add interactive notification whenever pdf file tries phoning author home html e-mail messages easily implement form phoning home images files required e-mail body may generate extra requests remote web server viewed ip address user computer sent web server unavoidable process reply required details embedded request urls identify user e-mail address marketing campaign etc extra page resources referred web bugs also used track off-line viewing uses ordinary web pages prevent activation requests many e-mail clients load images web resources html e-mails first viewed giving users option load images e-mail trusted source many malware applications phone home use gather store information person machine example pushdo trojan shows new complexity modern malware applications phoning home capabilities systems pushdo 421 executables available sent infected windows client surveillance cameras reported security researcher brian krebs secretly phone home manufacturer
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Computer security
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list features removed windows 7 windows 7 contains many new features however similarly transition windows xp windows vista certain capabilities programs present windows vista longer present windows 7 changed following list features originated earlier versions windows included windows vista
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Operating systems
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apache pig apache pig high-level platform creating programs run apache hadoop language platform called pig latin pig execute hadoop jobs mapreduce apache tez apache spark pig latin abstracts programming java mapreduce idiom notation makes mapreduce programming high level similar sql relational database management systems pig latin extended using user-defined functions udfs user write java python javascript ruby groovy call directly language apache pig originally developed yahoo research around 2006 researchers ad-hoc way creating executing mapreduce jobs large data sets 2007 moved apache software foundation example word count program pig latin program generate parallel executable tasks distributed across multiple machines hadoop cluster count number words dataset webpages internet comparison sql pig hand argued dbmss substantially faster mapreduce system data loaded loading data takes considerably longer database systems also argued rdbmss offer box support column-storage working compressed data indexes efficient random data access transaction-level fault tolerance pig latin procedural fits naturally pipeline paradigm sql instead declarative sql users specify data two tables must joined join implementation use specify implementation join sql thus ... many sql applications query writer may enough knowledge data enough expertise specify appropriate join algorithm. pig latin allows users specify implementation aspects implementation used executing script several ways effect pig latin programming similar specifying query execution plan making easier programmers explicitly control flow data processing task sql oriented around queries produce single result sql handles trees naturally built mechanism splitting data processing stream applying different operators sub-stream pig latin script describes directed acyclic graph dag rather pipeline pig latin ability include user code point pipeline useful pipeline development sql used data must first imported database cleansing transformation process begin
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Distributed computing architecture
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aggregation linguistics aggregation subtask natural language generation involves merging syntactic constituents sentences phrases together sometimes aggregation done conceptual level simple example syntactic aggregation merging two sentences john went shop john bought apple single sentence john went shop bought apple syntactic aggregation much complex example aggregation embed one constituents e.g. aggregate john went shop shop closed sentence john went shop closed pragmatic perspective aggregating sentences together often suggests reader sentences related case reader may confused example someone reads john went shop bought apple may infer apple bought shop case sentences aggregated aggregation algorithms must two things first issue deciding aggregate poorly understood aggegration decisions certainly depend semantic relations constituents mentioned also depend genre e.g. bureaucratic texts tend aggregated instruction manuals probably depend rhetorical discourse structure literacy level reader also probably important poor readers need shorter sentences integrated model brings factors together single algorithm regard second issue studies different types aggregation carried harbusch kempen describe several syntactic aggregation strategies terminology john went shop bought apple example forward conjunction reduction much less known conceptual aggregation di eugenio et al show conceptual aggregation done intelligent tutoring system demonstrate performing aggregation makes system effective conceptual aggregation make bigger impact syntactic aggregation unfortunately much software available performing aggregation however simplenlg system include limited support basic aggregation example following code causes simplenlg print man hungry buys apple
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Computational linguistics
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hypercast hypercast overlay middleware implemented java application-level overlay networks network applications use hypercast build overlay network top underlying networks internet without changing internet routing switching infrastructure hypercast supports multiple overlay topologies node discovery algorithms routing schemes multicast models etc designed simple interfaces application overlay functions allowing developers quickly create network applications without much knowledge internal details application-layer overlay networks hypercast introduces concept overlay sockets endpoints communication i.e node overlay network hypercast overlay network simply viewed collection overlay sockets overlay socket logical address physical address logical address unique address identifies node overlay network well route overlay messages among overlay sockets physical address overlay socket specifies address underlying network overlay socket send receive messages hypercast provides best-effort communication service unreliable unordered possible duplication application messages referred overlay messages hypercast implements secure distributed peer-to-peer naming service
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Distributed computing architecture
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wanda sykes wanda yvette sykes born march 7 1964 american actress comedian writer first recognized work writer chris rock show primetime emmy award 1999 2004 entertainment weekly named sykes one 25 funniest people america also known role barb baran cbs new adventures old christine 2006–10 hbo curb enthusiasm 2001–11 abc black-ish 2015–present aside television appearances sykes also career film appearing monster-in-law 2005 super ex-girlfriend 2006 evan almighty 2007 license wed 2007 well voicing characters animated films hedge 2006 barnyard 2006 brother bear 2 2006 rio 2011 2012 2016 animated film uglydolls 2019 born portsmouth virginia sykes family moved maryland third grade mother marion louise née peoples worked banker father harry ellsworth sykes u.s. army colonel employed pentagon sykes family history researched episode 2012 pbs genealogy program finding roots henry louis gates jr. ancestry traced back 1683 court case involving paternal ninth great-grandmother elizabeth banks free white woman indentured servant gave birth biracial child mary banks fathered slave inherited mother free status according historian ira berlin specialist history american slavery sykes family history case know possible trace black family rooted freedom late 17th century present sykes attended arundel high school gambrills maryland went graduate hampton university earned bachelor science degree marketing became member alpha kappa alpha college first job contracting specialist national security agency worked five years completely satisfied role national security agency nsa sykes began stand-up career coors light super talent showcase washington dc performed first time front live audience 1987 continued hone talents local venues nsa 1992 moved new york city one early tv appearances russell simmons def comedy jam early 1990s shared stage adele givens j b. smoove d. l. hughley bernie mac bill bellamy working hal leonard publishing house edited book entitled polyrhythms – musician guide peter magadini first big break came opening chris rock caroline comedy club 1997 joined writing team chris rock show also made many appearances show writing team nominated four emmys 1999 outstanding writing variety music comedy special since time appeared films pootie tang tv shows curb enthusiasm 2003 starred short-lived fox network sitcom wanda large year sykes appeared hour-long comedy central special tongue untied network also ranked 70 list 100 greatest all-time stand ups served correspondent hbo inside nfl hosted comedy central popular show premium blend voiced recurring character named gladys comedy central puppet show crank yankers also short-lived show comedy central called wanda addition film television work also author wrote yeah said book humorous observations various topics published september 2004 2006 landed recurring role barb opposite julia louis-dreyfus sitcom new adventures old christine became series regular series third season 2008 also guest starred grace episode buy buy baby 2006 provided voices 2006 films hedge barnyard brother bear 2 part super ex-girlfriend playing evan almighty bit part license wed sykes first hbo comedy special entitled wanda sykes sick tired premiered october 14 2006 nominated 2007 emmy award 2008 performed part cyndi lauper true colors tour lgbt rights october 2008 wanda sykes appeared television ad think speak campaign advertising campaign glsen aimed curbing homophobic slang youth communities 30-second spot uses humor scold teenager saying gay really means bad march 2009 announced sykes would host new late-night talk show saturdays fox wanda sykes show scheduled premiere november 7 2009 april 2009 named magazine annual power 50 list landing number 35 may 2009 sykes featured entertainer annual white house correspondents association dinner becoming first african american woman first openly lgbt person get role cedric entertainer first african american become featured entertainer 2005 event sykes made controversial headlines responded conservative radio talk show host rush limbaugh comments regarding president barack obama limbaugh reference obama presidential agenda said hope fails response sykes quipped hope limbaugh kidneys fail 'bout needs little waterboarding needs second comedy special wanda sykes i'ma premiered hbo october 2009 november 2009 saw premier wanda sykes show starts monologue continues panel discussion similar format bill maher shows real time bill maher politically incorrect appeared miss hannigan professional theatre production annie media theatre media pa suburb 25 minutes southwest philadelphia first appearance musical played role november 23 – december 12 2010 january 12–23 2011 voices witch bubble guppies episode bubble puppy fin-tastic fairlytale adventure 2012 sykes role voice granny 2016 returned voice granny blue sky studios ice age movies may 2013 sykes featured entertainer olivia travel 40th anniversary music comedy festival punta cana dominican republic 2013 sykes appeared eight episodes amazon alpha house political comedy series written doonesbury creator garry trudeau sykes plays rosalyn dupeche democratic senator illinois next door neighbor four republican senators living together house capitol hill sykes also appeared season two became available october 2014 series canceled second season 2018 announced sykes would head writer revived tenth season roseanne attracted attention due roseanne far-right conspiratorial views may 29 2018 sykes announced twitter would longer working series since-deleted twitter rant roseanne barr valerie jarrett sykes married record producer dave hall 1991 1998 november 2008 publicly came lesbian same-sex marriage rally las vegas regarding proposition 8 month earlier sykes married wife alex niedbalski french woman met 2006 couple also became parents april 2009 alex gave birth pair fraternal twins daughter son named olivia lucas sykes came conservative mother marion father harry 40 initially difficulty accepting homosexuality declined attend wedding alex led brief period estrangement since reconciled sykes proud grandparents couple children september 19 2011 appearance ellen degeneres show sykes announced diagnosed earlier year ductal carcinoma situ dcis although dcis non-invasive stage zero breast cancer sykes elected bilateral mastectomy order lower chances getting breast cancer. ref
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Computer security
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machine translation software usability sections give objective criteria evaluating usability machine translation software output repeated translations converge single expression languages i.e translation method show stationarity produce canonical form translation become stationary without losing original meaning metric criticized well correlated bleu bilingual evaluation understudy scores system adaptive colloquialism argot slang french language many rules creating words speech writing popular culture two rules reverse spelling words femme meuf called verlan b attachment suffix -ard noun verb form proper noun example noun faluche means student hat word faluchard formed faluche colloquially mean depending context group students gathering students behavior typical student google translator 28 december 2006 n't derive constructed words example rule b shown il une chorale falucharde mercredi venez nombreux les faluchards chantent des paillardes == choral society falucharde wednesday come many faluchards sing loose-living women french argot three levels usage united states national institute standards technology conducts annual evaluations machine translation systems based bleu-4 criterion combined method called iqmt incorporates bleu additional metrics nist gtm rouge meteor implemeneted gimenez amigo output grammatical well-formed target language using interlingua helpful regard fixed interlingua one able write grammatical mapping target language interlingua consider following arabic language input english language translation result google translator 27 december 2006 google translator output n't parse using reasonable english grammar repeated re-translations preserve semantics original sentence example consider following english input passed multiple times french using google translator 27 december 2006 noted kind round-trip translation unreliable method evaluation interesting peculiarity google translate 24 january 2008 corrected 25 january 2008 following result translating english spanish shows embedded joke english-spanish dictionary added poignancy given recent events raises issue trustworthiness relying machine translation system embedded life-critical system translation system input safety critical decision making process conjointly raises issue whether given use software machine translation system safe hackers known whether feature google translate result joke/hack perhaps unintended consequence use method statistical machine translation reporters cnet networks asked google explanation january 24 2008 google said internal issue google translate mistranslation subject much hilarity speculation internet unintended consequence use method statistical machine translation joke/hack event demonstration potential source critical unreliability statistical machine translation method human translations particular part interpreters selectivity part translator performing translation often commented one two parties served interpreter knows languages leads issue whether particular translation could considered verifiable case converging round-trip translation would kind verification
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Computational linguistics
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upsizing database upsizing term coined microsoft describe process upgrading microsoft access database microsoft sql server allows continue using microsoft access database front-end whereas actual back-end served separate local remote sql server allowing much higher productivity data volumes microsoft access version 2000 special upsizing wizard facilitates data migration proprietary microsoft sql server rdbms currently supported upsizing two strategies database migrated access sql server first strategy often seen first step towards complete migration sql server stage 2 seen part strategy 2 peculiarities every strategy see table data migration procedure microsoft access database upsizing requires fundamental refactoring database structure source code even though aspects procedure seem automatized upsizing wizard still many points requiring human intervention following changes done upsizing
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Databases
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brian krebs brian krebs born 1972 alabama american journalist investigative reporter best known coverage profit-seeking cybercriminals interest grew computer worm locked computer 2001 krebs author daily blog codice_1 covering computer security cybercrime 1995 2009 krebs reporter washington post covered tech policy privacy computer security well authoring security fix blog also known interviewing hacker 0x80 march 14 2013 krebs became one first journalists become victim swatting december 18 2013 krebs broke story target corporation breached 40 million credit cards six days later krebs identified ukrainian man krebs said behind primary black market site selling target customers credit debit card information much us 100 apiece 2014 krebs published book called spam nation inside story organized cybercrime global epidemic front door went win 2015 prose award krebs earned b.a international relations george mason university 1994 krebs started career washington post circulation department obtained job copy aide post newsroom split time sorting mail taking dictation reporters field krebs also worked editorial aide editorial department financial desk 1999 krebs went work staff writer newsbytes.com technology newswire owned washington post post sold newsbytes 2002 krebs transitioned washingtonpost.com arlington virginia full-time staff writer krebs stories appeared print edition paper washingtonpost.com 2005 krebs launched security fix blog daily blog centered around computer security cyber crime tech policy december 2009 krebs left washingtonpost.com launched krebsonsecurity.com krebs focused reporting blog fallout activities several organized cybercrime groups operating eastern europe stolen tens millions dollars small mid-sized businesses online banking fraud krebs written 75 stories small businesses organizations victims online banking fraud increasingly costly common form cybercrime krebs wrote series investigative stories culminated disconnection dissolution several internet service providers experts said catered primarily cyber criminals august 2008 series articles wrote washington post security fix blog led unplugging northern california based hosting provider known intercage atrivo time krebs published two-part investigation illicit activity domain name registrar estdomains one atrivo biggest customers showing company president vladimir tšaštšin recently convicted credit card fraud document forgery money laundering two months later internet corporation assigned names numbers icann entity charged overseeing domain registration industry revoked estdomains charter noting tšaštšin convictions violated icann policy prohibits officers registrar criminal record november 2011 tšaštšin five men would arrested estonian authorities charged running massive click fraud operation help dns changer trojan november 2008 krebs published investigative series led disconnection mccolo another northern california hosting firm experts said home control networks world largest botnets result krebs reporting mccolo upstream internet providers disconnected mccolo rest internet causing immediate sustained drop volume junk e-mail sent worldwide estimates amount duration decline spam due mccolo takedown vary 40 percent 70 percent weeks several months krebs credited first journalist 2010 report malware would later become known stuxnet 2012 cited follow-up another breach credit debit card data case potentially 10 million visa mastercard accounts transactions handled global payments inc. atlanta georgia 2016 krebs blog target one largest ever ddos attacks apparently retaliation krebs role investigating vdos botnet akamai hosting blog pro bono basis quit hosting blog result attack causing shut google project shield taken task protecting site also pro-bono basis article krebs 27 march 2018 krebsonsecurity.com mining software company script coinhive krebs published names admins german imageboard pr0gramm former admin inventor script owner company answered unusual protest action users imageboard using pun krebs meaning cancer german donated charitable organisations fighting diseases collecting 200,000 euro 245,000 usd donations evening 28 march deutsche krebshilfe charity krebs frequent speaker computer security cybercrime topics october 2011 gave keynote addresses
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Computer security
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ipad mini 3 ipad mini 3 stylized marketed ipad mini 3 third-generation ipad mini tablet computer designed developed marketed apple inc announced alongside ipad air 2 october 16 2014 released october 22 uses primarily design hardware predecessor ipad mini 2 new features addition touch id sensor compatible apple pay differing storage sizes available gold color well previous colors september 9 2015 ipad mini 3 discontinued replaced ipad mini 4 ipad mini 3 comes ios 8.1 operating system preinstalled comes several built-in applications camera photos messages facetime mail music safari maps siri calendar itunes store app store notes contacts ibooks game center reminders clock videos newsstand photo booth podcasts apple app store digital application distribution platform ios allows users browse download applications made various developers itunes store additional apps made apple available free download imovie garageband itunes u find iphone find friends apple store trailers remote iwork apps pages keynote numbers ipad mini 3 includes version apple pay built-in nfc functionality removed siri intelligent personal assistant knowledge navigator integrated device activated hands-free application uses natural language user interface answer questions make recommendations perform actions delegating requests set web services apple claims software adapts user individual preferences time personalizes results additionally siri identify songs using shazam listen song playing nearby siri stores list songs managed identify itunes facebook twitter come integrated apple native apps facebook features directly accessed within native apps calendar sync facebook events use facebook like button within apple app store ipad mini 3 uses almost exactly design ipad mini 2 addition touch id additionally announcement ipad mini 3 ipad air 2 apple added gold color option existing silver space gray color choices ipads ipad mini 3 uses nearly hardware ipad mini 2 main exception addition touch id sensor 7.9 retina display 2048-by-1536-pixel resolution 326 ppi ipad mini 3 also uses a7 chip 64-bit architecture m7 motion coprocessor 5mp isight camera capable recording 1080p hd video 1.2mp facetime hd camera capable recording 720p hd video new touch id sensor detects user fingerprint used instead passcode unlock ipad touch id ipad mini 3 also compatible apple pay used authorize purchases online apps fingerprint verification opposed entering passwords ipad mini 3 available storage options 16 64 128gb expansion option apple released camera connection kit sd card reader used transfer photos videos ipad ipad mini 3 received positive reviews drew fainter praise predecessor identical ipad mini 2 except addition touch id availability gold color ipad mini 2 regarded better buy 100 usd cheaper featuring screen internals mini 2 3 stuck hardware level original ipad air ipad air 2 new hardware considerably powerful furthermore air 2 also redesigned lighter smaller original air nullified advantages mini 2 3 compact form factor
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Operating systems
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open identity exchange open identity exchange oix membership organisation works accelerate adoption digital identity services based open standards non-profit organisation technology agnostic collaborative works across private public sectors members work together jointly fund participate pilot projects sometimes referred alpha projects pilots test business legal and/or technical concepts theory interoperability real world use cases white paper published every project shortly coming office obama administration asked u.s. general services administration gsa leverage open identity technologies allow american public easily efficiently safely interact federal websites national institute health nih social security administration ssa internal revenue service irs 2009 rsa conference gsa sought build public/private partnership open id foundation oidf information card foundation icf order craft workable identity information framework would establish legal policy precedents needed establish trust open id transactions partnership eventually developed trust framework model described meetings held internet identity workshop november 2009 resulted oidf icf forming joint steering committee committee task study best implementation options newly created framework us chief information officer recommended formation non-profit corporation open identity exchange oix january 2010 oidf icf approved grants fund creation open identity exchange oix first trust framework provider certified us government booz allen hamilton ca technologies equifax google paypal verisign verizon members either oidf icf agreed become founding members oix open identity exchange publicly launched rsa 2010 addressed increasing challenges building trust online identity outlined 2012 executive director position founded national strategy trusted identities cyberspace nstic pilot projects showed growing proof traction increased awareness attention 2012 oix uk formed throughout 2013 initial uk cabinet office identity assurance programme idap pilots launched white papers published 2014 oix established oixnet trust registry global authoritative registry business legal technical requirements needed ensure market adoption global interoperability 2014 oidf also announced plans register companies self-certifying conformance openid connect via openid certification program oixnet official online publicly-accessible repository documents information relating identity systems identity system participants referred “ registry ” functions official centralized source documents information much like government-operated recorder deeds individuals entities register documents information oixnet registry provide notice contents public members public seeking access documents information go single authoritative location find oixnet registry designed provide single comprehensive authoritative location documents information relating specific purpose case identity systems safely stored purpose putting others notice certain facts documents information accessed interested stakeholders seeking information oixnet launched 2015 openid foundation first registrant registering initial set organizations including google forgerock microsoft nri paypal ping identity certifying conformance openid connect additional registrations added oixnet throughout 2015 2016 10 trusted identity services currently registered oixnet registry currently pilot 2016 registering new diverse trust frameworks communities interest oix developed chapters policy 2015 allows regional oix chapters established 2016 oix united kingdom chapter approved oix board launched oix board represents leaders online identity internet telecom data aggregation industries concerned market expansion information security oix board met howard schmidt 2011 discuss public–private partnership envisioned nstic strategy uk government cabinet office joined oix board level began work identity assurance programme gov.uk verify states jersey joined 2015 could leverage knowledge gained development uk government identity assurance programme hasten adaptation adoption jersey open identity exchange currently thirteen executive members 50+ general members november 2016 executive members beginning 2015 cabinet office requested open identity exchange begin process exploring legal business pragmatic considerations creating self-sustaining uk ‘ chapter ’ open identity exchange point oix uk operated independent uk entity able administer ‘ directed funding ’ member organisations received series grants uk cabinet office used collaboratively funded projects ad-hoc board advisers formed independent experienced public private sector leaders addressed policy considerations transition process addition considering role oix uk future board advisers considered private sector ’ needs identity services resulting ongoing oix project open identity exchange board directors approved oix chapters policy end 2015 allowing formation individual chapters affiliated oix various local markets april 2016 oix uk europe chapter appointed board directors oix white papers deliver joint research examine wide range challenges facing open identity market provide possible solutions written experts fields technology particularly open identity open identity exchange oix white papers focus current issues opportunities emerging identity markets oix white papers intended deliver value identity ecosystem take one two perspectives retrospective report outcome given project pilot prospective discussion current issue opportunity oix white papers authored independent domain experts intended summaries general business audience recent published whitepapers include • use online activity part identity verification • uk private sector needs identity assurance • use digital identity peer-to-peer economy • shared signals proof concept • creating digital identity jersey • giving gov.uk verify • creating pensions dashboard • could digital identities help transform consumers attitudes behavior towards savings • digital identity across borders opening bank account another eu country • generating revenue subscriber benefits analysis arpu identity oix projects deliver joint research examine wide range challenges facing open identity market provide possible solutions hypothesis uk government identity assurance model could adapted jersey support certified uk idps potential identity assurance hub providers meet requirements soj hypothesis also considered would create attractive market opportunity jersey one providers 3-year project started september 2016 partially funded european union horizon 2020 research innovation programme g.a 700321 lightest consortium consists 14 partners 9 european countries coordinated fraunhofer-gesellschaft project looks reach beyond europe build global community lightest lightweight infrastructure global heterogeneous trust management support open ecosystem stakeholders trust schemes objective lightest create global cross-domain trust infrastructure renders transparent easy verifiers evaluate electronic transactions querying different trust authorities worldwide combining trust aspects related identity business reputation etc become possible conduct domain-specific trust decisions achieved reusing existing governance organization infrastructure standards software community know-how existing domain name system combined new innovative building blocks approach allows efficient global rollout solution assists decision makers trust decisions integrating mobile identities scheme lightest also enables domain-specific assessments levels assurance identities uk government cabinet office joined oix board level began work identity assurance programme idap oix directed funding programme considerable number projects continue carried oix governance results helped ongoing development gov.uk verify work continues gds looks digital identities used public private sector gov.uk verify built maintained government digital service gds part cabinet office uk government committed expanding gov.uk verify helping grow market identity assurance able meet user needs relation central government services well local health private sector services gov.uk verify uses certified companies verify identity government certified company private company works high industry government standards verify identity
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Computer security
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database design database design organization data according database model designer determines data must stored data elements interrelate information begin fit data database model database design involves classifying data identifying interrelationships theoretical representation data called ontology ontology theory behind database design majority cases person design database person expertise area database design rather expertise domain data stored drawn e.g financial information biological information etc therefore data stored database must determined cooperation person expertise domain aware data must stored within system process one generally considered part requirements analysis requires skill part database designer elicit needed information domain knowledge necessary domain knowledge frequently express clearly system requirements database unaccustomed thinking terms discrete data elements must stored data stored determined requirement specification database designer aware data stored within database must determine dependency within data sometimes data changed changing data visible example list names addresses assuming situation multiple people address one person one address address dependent upon name provided name list address uniquely determined however inverse hold given address list name uniquely determined multiple people reside address address determined name address considered dependent name relationships dependencies amongst various pieces information determined possible arrange data logical structure mapped storage objects supported database management system case relational databases storage objects tables store data rows columns object database storage objects correspond directly objects used object-oriented programming language used write applications manage access data relationships may defined attributes object classes involved methods operate object classes way mapping generally performed set related data depends upon single object whether real abstract placed table relationships dependent objects stored links various objects table may represent implementation either logical object relationship joining one instances one logical objects relationships tables may stored links connecting child tables parents since complex logical relationships tables probably links one parent database designs also include er entity-relationship model diagrams er diagram diagram helps design databases efficient way attributes er diagrams usually modeled oval name attribute linked entity relationship contains attribute field relational database design normalization systematic way ensuring database structure suitable general-purpose querying free certain undesirable characteristics—insertion update deletion anomalies could lead loss data integrity standard piece database design guidance designer create fully normalized design selective denormalization subsequently performed performance reasons trade-off storage space vs performance normalized design less data redundancy therefore takes less space store however common data retrieval patterns may need complex joins merges sorts occur takes data read compute cycles modeling disciplines dimensional modeling approach data warehouse design explicitly recommend non-normalized designs i.e designs large part adhere 3nf normalization consists normal forms 1nf,2nf,3nf boyce-codd nf 3.5nf ,4nf 5nf document databases take different approach document stored database typically would contain one normalized data unit often relationships units well data units relationships question often retrieved together approach optimizes number retrieves also simplifies data gets replicated clearly identifiable unit data whose consistency self-contained another consideration reading writing single document databases require single transaction important consideration microservices architecture situations often portions document retrieved services via api stored locally efficiency reasons data units split across services read write support service consumer might require one service calls could result management multiple transactions may preferred schema refinement database specifies data normalized reduce data insufficiency conflicts physical design database specifies physical configuration database storage media includes detailed specification data elements data types indexing options parameters residing dbms data dictionary detailed design system includes modules database hardware software specifications system
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Databases
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army moves army moves scrolling shooter game developed dinamic software amiga amstrad cpc atari st commodore 64 msx zx spectrum first chapter moves trilogy followed navy moves 1987 arctic moves 1995 first released 1986 published dinamic spain imagine software dinamic software also developed ms-dos version game published 1989 spain game contains seven levels divided two main sections first four levels make first section player drive army unit jeep helicopter terrain steering clear hostile vehicles last three levels comprise second main section one plays soldier shoots enemies along way level 5 soldier must jump rock rock river shooting hostile birds thereafter soldier makes way enemy headquarters goal retrieving secret documents army moves regarded rather bad game amiga — almost non-existent gameplay makes poor value money according review zzap however received mixed reviews zx spectrum magazines successful enough spain spawn two follow-ups navy moves 1988 arctic moves 1995 latter appeared pc platform included first two chapters series playable zx spectrum emulator extra fourth entry series desert moves announced end game arctic moves never appeared game music non-spanish versions based colonel bogey march
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Computer architecture
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apache spark apache spark open-source distributed general-purpose cluster-computing framework spark provides interface programming entire clusters implicit data parallelism fault tolerance originally developed university california berkeley amplab spark codebase later donated apache software foundation maintained since apache spark architectural foundation resilient distributed dataset rdd read-only multiset data items distributed cluster machines maintained fault-tolerant way dataframe api released abstraction top rdd followed dataset api spark 1.x rdd primary application programming interface api spark 2.x use dataset api encouraged even though rdd api deprecated rdd technology still underlies dataset api spark rdds developed 2012 response limitations mapreduce cluster computing paradigm forces particular linear dataflow structure distributed programs mapreduce programs read input data disk map function across data reduce results map store reduction results disk spark rdds function working set distributed programs offers deliberately restricted form distributed shared memory spark facilitates implementation iterative algorithms visit data set multiple times loop interactive/exploratory data analysis i.e. repeated database-style querying data latency applications may reduced several orders magnitude compared apache hadoop mapreduce implementation among class iterative algorithms training algorithms machine learning systems formed initial impetus developing apache spark apache spark requires cluster manager distributed storage system cluster management spark supports standalone native spark cluster hadoop yarn apache mesos kubernetes distributed storage spark interface wide variety including alluxio hadoop distributed file system hdfs mapr file system mapr-fs cassandra openstack swift amazon s3 kudu lustre file system custom solution implemented spark also supports pseudo-distributed local mode usually used development testing purposes distributed storage required local file system used instead scenario spark run single machine one executor per cpu core spark core foundation overall project provides distributed task dispatching scheduling basic i/o functionalities exposed application programming interface java python scala r centered rdd abstraction java api available jvm languages also usable non-jvm languages connect jvm julia interface mirrors functional/higher-order model programming driver program invokes parallel operations map filter reduce rdd passing function spark schedules function execution parallel cluster operations additional ones joins take rdds input produce new rdds rdds immutable operations lazy fault-tolerance achieved keeping track lineage rdd sequence operations produced reconstructed case data loss rdds contain type python java scala objects besides rdd-oriented functional style programming spark provides two restricted forms shared variables broadcast variables reference read-only data needs available nodes accumulators used program reductions imperative style typical example rdd-centric functional programming following scala program computes frequencies words occurring set text files prints common ones variant takes anonymous function performs simple operation single data item pair items applies argument transform rdd new rdd spark sql component top spark core introduced data abstraction called dataframes provides support structured semi-structured data spark sql provides domain-specific language dsl manipulate dataframes scala java python also provides sql language support command-line interfaces odbc/jdbc server although dataframes lack compile-time type-checking afforded rdds spark 2.0 strongly typed dataset fully supported spark sql well spark streaming uses spark core fast scheduling capability perform streaming analytics ingests data mini-batches performs rdd transformations mini-batches data design enables set application code written batch analytics used streaming analytics thus facilitating easy implementation lambda architecture however convenience comes penalty latency equal mini-batch duration streaming data engines process event event rather mini-batches include storm streaming component flink spark streaming support built-in consume kafka flume twitter zeromq kinesis tcp/ip sockets spark 2.x separate technology based datasets called structured streaming higher-level interface also provided support streaming spark mllib distributed machine-learning framework top spark core due large part distributed memory-based spark architecture much nine times fast disk-based implementation used apache mahout according benchmarks done mllib developers alternating least squares als implementations mahout gained spark interface scales better vowpal wabbit overview spark mllib exists many common machine learning statistical algorithms implemented shipped mllib simplifies large scale machine learning pipelines including graphx distributed graph-processing framework top apache spark based rdds immutable graphs immutable thus graphx unsuitable graphs need updated let alone transactional manner like graph database graphx provides two separate apis implementation massively parallel algorithms pagerank pregel abstraction general mapreduce-style api unlike predecessor bagel formally deprecated spark 1.6 graphx full support property graphs graphs properties attached edges vertices graphx viewed spark in-memory version apache giraph utilized hadoop disk-based mapreduce like apache spark graphx initially started research project uc berkeley amplab databricks later donated apache software foundation spark project spark initially started matei zaharia uc berkeley amplab 2009 open sourced 2010 bsd license 2013 project donated apache software foundation switched license apache 2.0 february 2014 spark became top-level apache project november 2014 spark founder m. zaharia company databricks set new world record large scale sorting using spark spark excess 1000 contributors 2015 making one active projects apache software foundation one active open source big data projects given popularity platform 2014 paid programs like general assembly free fellowships like data incubator started offering customized training courses spark deployed traditional on-premises data center well cloud cloud allows organizations deploy spark without need acquire hardware specific setup expertise providers managed spark solutions enterprise strategy group esg-global.com found 43 respondents considering cloud primary deployment spark top reasons customers perceived cloud advantage spark faster time deployment better availability frequent feature/functionality updates elasticity geographic coverage costs linked actual utilization
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Distributed computing architecture
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l-carrier l-carrier system one series carrier systems developed high-capacity transmission long-distance communications period late 1930s 1970s system evolved six significant phases development designated bell system engineers l-1 l-5 l-5e coaxial cable principle transmission medium stages initially lending system another descriptions coaxial system successor series previous carrier systems typically identified capital letters 1960s system hardened dangers cold war using complete placement terminal repeater equipment hardened underground vaults initial development testing coaxial system took place 1935 1937 test bed 95-mile two-way coaxial cable locations new york city philadelphia distance 3800 miles simulated repeatedly remodulating signals looping twenty times endpoints system provided 240 channels single circuit first production installation l-1 carrier system went service stevens point wi minneapolis mn 1941 distance almost 200 miles capacity 480 channels far could carried balanced pair carrier systems cheaper per channel high-usage routes small-scale l2 system baltimore md washington dc intended short-distance low-volume traffic abandoned early stage anticipation end war-time responsibilities announced december 1944 development plan nationwide build-out coaxial carrier network support long-distance telephone service also television transmissions result post-war research goal definition l-3 carrier system successive version least twice many channels previous version culminating l-5e design 1976 long lines built two coast-to-coast systems l-3 well shorter ones connecting major cities especially big cities eastern united states supplement mainstay microwave radio relay systems later upgraded l-4 others simply overbuilt new l-5 system starting 1911 telephone networks used frequency-division multiplexing carry several voice channels single physical circuit beginning first type c carrier year heterodyned three voice channels stacked top one voice circuit l-carrier systems loaded multiplexing supermultiplexing single sideband channels using long-standard 12 channel voice group produced type channel banks occupying frequency spectrum 60 108 khz basic group entire line spectrum previous long haul carrier systems types j k. first type a-1 channel banks appeared use type j open wire carrier 1934 work espenschied herman affel bell labs patented piezoelectric crystal lattice filters provide sharp bandpass cutoff made single-sideband carrier work lattice filters heart analog multiplex systems using single-sideband/carrier suppressed architecture active ic-based filtering became available mid-1970s single-sideband modulation schemes twelve voice channels would modulated channel group turn five groups could multiplexed similar method supergroup containing 60 voice channels one 48 khz group-band circuit sometimes used single high speed data link rather voice circuits also entire supergroups could dedicated single data channel running data rate 56 kbit/s early late 1960s long distance systems supergroups multiplexed mastergroups 300 voice channels european ccitt hierarchy 600 long lines type l-600 multiplex transmission coaxial cable microwave even higher levels multiplexing became possible send thousands voice channels single circuit example type l-4 system used multi-master group system stack six u600 mastergroups l4 line spectrum hardware modified take three mmg spectra stack early l5 line spectrum later advancements technology allowed even stacking type l-5e allowing 22 mastergroups stacked 66 mhz line spectrum accompanying diagrams process bell system type channel bank forming mastergroup three stages l-carrier also carried first television network connections though later microwave radio relay system soon became important purpose type l-3 used short time coast-to-coast network television feeds advent ntsc color cause move type td microwave radio tube repeaters l-3 added much group delay baseband broadcast signal cables much use broadcasters l-pipes n't used broadcast television much around 1964 variant 1950s l-3 system designed early 1960s provide land line connections key military command control facilities united states starting l-3i improved system upgraded able withstand nuclear attack system consisted 100 main stations 1000 individual repeater vaults main stations emergency power systems blast doors accommodations staff two-week post-attack period nuclear early warning systems blast detection emergency services generally provided redundant underground microwave circuits case one failed late 1970s early 1980s l-carrier system determined redundant advance satellite fiber-optic communication cables upgraded t-4 t-5 instead l-5 never upgraded past l-4 due advancement technology generally advancement glass fiber laser technology made copper coaxial cable obsolete long haul carrier service western electric fielded ft series g single-mode fiber cable system 1984
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Internet protocols
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amlogic amlogic sometimes stylized amlogic american technology company founded us amlogic inc. predominantly focused designing selling soc system chip integrated circuits like fabless companies industry company outsources actual manufacturing chips third-party independent chip manufacturers tsmc main target applications entertainment devices android-based tv iptv/ott set-top boxes media dongles smart tvs tablets offices shanghai beijing shenzhen taipei hong kong santa clara california company founded 1995 silicon valley developed video cd player chips later chips dvd players applications involving mpeg2 decoding amlogic involved creation hvd high-definition versatile disc standard promoted china alternative dvd video disks used dvd players company player developing chinese tablet processor market since 2010-2013 amlogic arm licensee uses arm architecture majority products according joint press release arm 2013 first company use arm mali-450 gpu configuration six cores m801/802 uses new version arm cortex-a9 core a9r4 theoretically allows higher clock speeds lower power consumption compared older versions cortex a9 core a9r3 used rockchip rk3188 originally scheduled production early middle 2013 form aml8726-m8 april 2014 one tablet onda v975m announced using chip m8 family manufacturers shown android tv boxes using m802 shenzhen tomato technology tronsmart eny technology geniatech noted devices using m802 may run hot use heatsink cooling common among popular ott set top boxes amazon firetv uses metal shell disperse heat much like heatsink would amlogic also offers soc products s802 s805 s812 specifically targeting android tv boxes ott set-top boxes variations similar socs series targeting tablets s8**-h models include dolby/dts licenses first 64-bit amlogic products lineup s9** -h models include dolby/dts licenses devices based already market running android 5.1 7.1 usually paired 1gb 2gb 3gb ram 8gb 64gb flash mem features gigabit lan dual band 2.4g/5g a/c wifi s905x scheduled released q1 2016 s905d s912 scheduled q2 2016 three socs android marshmallow buildroot linux sdks released ibc 2018 amlogic showed public first time second generation socs media players reference boards running android tv 9 q3 2017 amlogic released new socs targeting smart speakers audio applications amlogic mx s802 s805 socs also targeted media dongles amlogic also offers socs targeting smart tvs projectors including m6l m6c m6d t826 t828 t866 t868 t962 t966 t968 amlogic publish sales financial information website company listed client several venture capital firms market socs targeting chinese tablet manufacturers manufacturers android media players tv boxes media dongles faces competition primarily rockchip allwinner technology actions semiconductor mediatek intel realtek amlogic reported fourth largest application processor supplier chinese tablets 2012 q2 2014 amlogic reported fifth largest supplier rockchip mediatek allwinner actions semiconductor chinese soc suppliers cellular baseband technology disadvantage compared companies mediatek also supply smartphone market white-box tablet makers increasingly add phone functionality products 2011 aml8726-m selected one hottest processors ee times china 2012 aml8726-mx ee times-china processor year award amlogic maintains website dedicated providing source code linux kernel android sdk supporting amlogic chips reference designs linux kernel source code freely available recently april 2014 updated support certain chips m8 family well older mx family android versions 4.4 kitkat supported based linux kernel version 3.10.x however android sdk requires nda available business partners source code includes linux kernel 3.10.10 u-boot realtek broadcom wi-fi drivers nand drivers “ tvin ” drivers kernel space gpu drivers mali-400/450 gpu xbmc/kodi amlogic s805 m805 s806 m806 s812 android video decoding compatibility list http //kodi.wiki/view/android_hardware compatible_chipsets however effort push linux upstream support gx arm64 lineup ongoing http //linux-meson.com/ currently aml8726mx s802 s805 s905 soc booting headless linux 4.8 s905x s905d s912 headless support expected linux 4.10
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Computer architecture
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hermann bottenbruch hermann bottenbruch born september 14 1928 german mathematician computer scientist bottenbruch grew german state north rhine-westphalia toward end second world war served 1947 began study mathematics graduated 1951 following graduation joined staff institute applied mathematics tu darmstadt institute founded alwin walther bottenbruch earned doctorate 1957 year walther recommendation joined international working group develop new programming language language intended combine current understanding programming languages single standard according friedrich bauer bottenbruch coined name algol least germany english algorithmic language “ 1958 members working group—friedrich l. bauer bottenbruch heinz rutishauser klaus samelson john backus charles katz alan perlis joseph henry wegstein—met eth zurich result deliberations algol 58 1960 1961 bottenbruch worked us oak ridge national laboratory took leading position german industry among things served specialist area industrial chimney construction 1994 founded company primasoft gmbh german city oberhausen providing consulting database solutions
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Programming language topics
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ruth a. david ruth a. david born 1953 american engineer cia david responsible encouraging agency pursue partnerships private sector designed proposal procure technology stage development private sector awarded cia director award defense intelligence agency director award cia distinguished intelligence medal national reconnaissance officer award distinguished service national security agency distinguished service medal ruth a. david born may 13 1953 arkansas city kansas attaining bs electrical engineering wichita state university 1975 went earn master 1976 phd 1981 electrical engineering stanford university david began career 1975 holding several positions sandia national laboratories albuquerque new mexico served adjunct professor university new mexico teaching adaptive digital signal digital microprocessor system design linear least-squares estimation 1986 employed supervisor data systems development organization responsible developing remote controlled digital system deployment underground nuclear tests nevada test site three years later transferred federal aviation administration managing department non-destructive test electromagnetic test optics program aging aircraft 1991 1994 david director development testing center supervising broad spectrum engineering test facilities 1995 appointed deputy director science technology central intelligence agency became responsible advising agency science technology capacity proposed radical new approach agency deal swift growth information internet revolution rather procuring technology developed david deputy joanne isham recognized pushed agency pursue partnerships within private sector technology advancing far faster government bureaucracy procurement program could secure new innovation proposed technology obtained stage development private sector recommended utilizing technology streamline processes move away simply collecting data toward analytical leveraged position disseminating exploiting information 1998 david left cia awarded cia director award defense intelligence agency director award cia distinguished intelligence medal national reconnaissance officer award distinguished service national security agency distinguished service medal year david joined anser formerly analytic services inc. president chief executive officer anser provided analysis research public service national transnational security issues 1999 developed homeland defense strategic thrust focus research internal external terrorist entities hostile nations expanded department anser institute homeland security 2001 provide public awareness education national security 2010 david inducted women technology international hall fame appointed president obama member national science board national science foundation 2012 david retired anser 2015
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Computer security
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speculative execution speculative execution optimization technique computer system performs task may needed work done known whether actually needed prevent delay would incurred work known needed turns work needed changes made work reverted results ignored objective provide concurrency extra resources available approach employed variety areas including branch prediction pipelined processors value prediction exploiting value locality prefetching memory files optimistic concurrency control database systems speculative multithreading special case speculative execution modern pipelined microprocessors use speculative execution reduce cost conditional branch instructions using schemes predict execution path program based history branch executions order improve performance utilization computer resources instructions scheduled time yet determined instructions need executed ahead branch speculative computation related earlier concept eager execution form speculative execution sides conditional branch executed however results committed predicate true unlimited resources eager execution also known oracle execution would theory provide performance perfect branch prediction limited resources eager execution employed carefully since number resources needed grows exponentially level branch executed eagerly predictive execution form speculative execution outcome predicted execution proceeds along predicted path actual result known prediction true predicted execution allowed commit however misprediction execution unrolled re-executed common forms include branch predictors memory dependence prediction generalized form sometimes referred value prediction lazy execution involve speculation incorporation speculative execution implementations haskell programming language current research topic eager haskell designed around idea speculative execution 2003 phd thesis made ghc support kind speculative execution abortion mechanism back case bad choice called optimistic execution deemed complicated starting 2017 series security vulnerabilities found implementations speculative execution common processor architectures effectively enabled elevation privileges include
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Computer architecture
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ipfilter ipfilter commonly referred ipf open-source software package provides firewall services network address translation nat many unix-like operating systems author software maintainer darren reed ipfilter supports ipv4 ipv6 protocols stateful firewall ipfilter delivered freebsd netbsd solaris 10 11 illumos used part openbsd removed may 2001 due problems license negotiations theo de raadt reed broke subsequently replaced openbsd pf developed openbsd developers dragonfly bsd removed support ipfilter may 2011 ipfilter installed runtime-loadable kernel module directly incorporated operating system kernel depending specifics kernel user preferences software documentation recommends module approach possible operating systems support ipfilter include
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Computer security
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ping identity ping identity corporation software company established 2000 andre durand bryan field-elliot headquartered denver colorado united states development offices denver colorado bangalore india ping also european operations offices london paris switzerland well offices bangalore melbourne tokyo serving asia-pacific company software provides federated identity management web identities via attribute based access controls similar identity management system tools developed microsoft okta products include pingid pingfederate pingone pingaccess pingdirectory pingdataconvernance pingintelligence ping identity received number rounds funding beginning series apr 16 2004 since received 35m kohlberg kravis roberts sep 18 2014 44m dfj growth w capital partners jul 16 2013 well 21m silicon valley bank triangle peak partners jun 21 2011 13m appian ventures vista equity partners private equity firm based san francisco acquired majority ownership ping identity leveraged buyout 600m jun 1 2016 ping already taken 125m funding point ping valued 2b 3b vista equity partners take company public rather sell often case vista goldman sachs leading ping identity ipo company partnered salesforce.com oracle crm on-demand vendavo pros provide identity management centralized login organizations july 2012 eran hammer resigned role lead author oauth 2.0 project withdrew ietf working group removed name specification due conflict web enterprise cultures hammer gave presentation conference explaining views citing ietf community enterprise use cases capable simple oauth initially designed oauth 2.0 blueprint authorization protocol says enterprise way providing whole new frontier sell consulting services integration solutions
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Distributed computing architecture
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project shield project shield anti-distributed-denial-of-service anti-ddos service offered jigsaw subsidiary google parent company alphabet inc. websites media elections human rights related content main goal project serve small under-resourced news sites vulnerable web ’ growing epidemic ddos attacks according team lead george conard similar services offered companies like cloudflare google initially announced project shield ideas conference october 21 2013 service initially offered trusted testers february 25 2016 google opened service qualifying website google-owned reverse proxy identifies filters malicious traffic may 2018 jigsaw announced would start offering free protection distributed denial service attacks us political campaigns candidates political action committees setting project shield involves changing dns domain traffic website goes google ’ system gets front page project shield provides news human rights elections monitoring sites protection ddos distributed denial service system caching storing data protected website reduce load site also filters traffic thwart ddos attacks project shield built google cloud services provided free charge qualifying websites independent journalists human rights elections monitoring websites protect regardless location project shield 2016 october users europe asia north america africa
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Computer security
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konami game master utility cartridge released konami december 12 1985 meant used conjunction konami msx game cartridges allowing users select stages adjust number lives save progress high scores make screen dumps play slow motion among uses updated model called released february 18 1988 new version adds support msx2 games features battery backup allows users save data via s-ram compatible games
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Computer architecture
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sapphire rapids sapphire rapids intel cpu microarchitecture based either second refinement 10 nanometer process new 7 nanometer process used part tinsley workstation server platform 2020 limited information desktop/mobile version sapphire rapids exists difficulties 10 nm 7 nm fabrication processes may result release pushed back 2021 earliest
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Computer architecture
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sawzall programming language sawzall procedural domain-specific programming language used google process large numbers individual log records sawzall first described 2003 szl runtime open-sourced august 2010 however since mapreduce table aggregators released open-sourced runtime useful large-scale data analysis multiple log files shelf sawzall replaced lingo logs go purposes within google google server logs stored large collections records protocol buffers partitioned many disks within gfs order perform calculations involving logs engineers write mapreduce programs c++ java mapreduce programs need compiled may verbose necessary writing program analyze logs time-consuming make easier write quick scripts rob pike et al developed sawzall language sawzall script runs within map phase mapreduce emits values tables reduce phase script writer concerned aggregates tables multiple runs single set tables currently language runtime runs sawzall script single input open-sourced supporting program built mapreduce released interesting features include sawzall design favors efficiency engine simplicity power complete sawzall program read input produce three results number records sum values sum squares values
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Programming language topics
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mill architecture mill architecture novel belt machine-based computer architecture general-purpose computing development since 2003 ivan godard startup mill computing inc. formerly named box computing east palo alto california mill computing claims 10x single-thread power/performance gain conventional out-of-order superscalar architectures runs programs without rewrite mill computing founded persons formerly worked together family digital signal processors dsps philips trimedia designers claim power cost improvements come adapting dsp-like deeply-pipelined processor general-purpose code timing hazards branches memory access said handled via speculative execution pipelining late binding statically-scheduled logic claimed improvements power area said come eliminating dynamic optimizing hardware register-renaming out-of-order execution hazard management dynamic cache optimizing replace hardware mill processor designed timing memory-access behavior predictable single cycles scheduling subject highly-optimizing compiler mill uses long instruction word vliw -style encoding store 33 simple operations wide instruction words termed opcodes mill uses two program counters every wide instruction split two parts one program counters counts backward code every linear instruction block executed middle outside two almost independent decoders unused operations deleted small fixed-format data item center instruction helps maintain code density reducing incidence no-operation codes mill code also allows functional unit start speculatively executing instruction field discard result instruction ivan godard designer mill quotes research finding operation standard register machine values stored processor registers 6 accessed never 80 14 thus mill uses novel temporal register addressing scheme belt analogy conveyor belt operands arithmetic logic units alus functional units may taken position belt result computation dropped stored front position belt advancing belt make room belt fixed length drops front matched older operands falling back pushed-off operands become inaccessible must explicitly saved still needed later work operations instruction set work data belt data registers main memory cells typical instruction like codice_1 argument operands come explicitly named positions belt result dropped front ready next instruction operations multiple results simply drop values belt front example division produce quotient remainder operations overflow produce double-wide results belt instructions encoded operation code opcode two belt positions added fields specify result register memory address literal constant encoding easily extended richer operations two inputs one result constant operands dropped separate codice_2 instructions access program variables main random-access memory ram segregated separate codice_3 codice_4 instructions containing one memory address way calculate address belt operands belt machines variants load/store opcodes access local variables heap offsets pointer belt various special-purpose base registers similarly instructions branch address taken belt along branches relative program counter drop result moves prior belt content along later positions queue given operand continually changes position hence address result later execution effect access operand position zero request recent value dropped belt example reference position five sixth recent drop thus addresses belt operands reflect belt history time temporal addressing hard human programmers keep track belt contents hence operand addresses writing assembly code belt machine however easy compiler track changing contents emit correct position addresses generated code belt fixed length may short hold live transient operands pushed end operand needed longer belt lifetime must saved still belt spill later restored belt needed fill situation equivalent need spill registers memory program runs registers general-register machine spilled operands may written memory using normal store instructions restored using normal load instructions spill fill may use special-purpose storage associated operations faster offer advantages load store operands belt read-only new results overwrite prior values belt thus single-assignment structure immune data hazards must dealt modern out-of-order general-register machines dense machine code valuable 1960s main memory costly limited even mainframe computers became important initially-tiny memories minicomputers microprocessors density remains important today applications smartphone downloaded browsers slow internet connections read-only memory rom embedded applications general advantage increased density improved effectiveness caches instruction prefetch belt machines smaller instructions register-based machines due needing destination address results saving make significant difference fixed-length instruction formats normally use power-of-two instruction widths thirty-two addressable elements registers general-register machine belt positions belt machine element address occupies five bits instruction needing 15 bits three-address format general-register machine 10 bits using two-address format belt machine bits also needed opcode information instruction power-of-two constrained instruction width often determines maximum number addressable elements possible design typically belt machine instruction support encoding double number addressable elements compared general-register machine instruction width similar gains variable-length instruction encodings overall belt machine code less compact stack machines use operand addresses often must introduce stack-manipulation instructions unneeded belt machine instructions accumulator machines padded multiple register fields instead use return stack need extra memory reference instructions belt machine presents operand queue program model mill architecture n't implement belt physical queue shift register implemented hardware instead semantic representation bypass network present fast computers intercepts pipelined accesses registers routing directly execution units need result number registers reasonably small needed pipeline output functional unit one possible belt item small number registers reduces size power complexity network access registers live data values kept conveniently addressable physical resources individual registers register files static random-access memory sram operand forwarding functional units generally moved duration belt lifetime instruction decoder maps logical belt positions physical locations mapping updated reflect changes logical position arising newly dropped results patent belt granted 2016 depending type success load operations mill also assigns metadata belt item including status width vectorization count operations operate item described thus width vector count part instruction coding operation fails failure information hashed placed destination metadata use debugging mill also uses metadata assist speculative execution pipelining example vector load operation fails e.g. part leaves protection boundary parts belt entry marked codice_5 nar metadata allows speculatively-executed vector code emulate per-vector-item fault behavior nar items create fault attempt occurs store perform non-speculative code never used fault ever created mill architecture appears able reduce size complexity pipelined loop code pipeline video every operation required cope special operand value called codice_6 confused codice_7 floating point formats special semantics purpose operations least one argument codice_6 generally produce codice_6 output codice_6 attempted stored memory store portion store vectors elements codice_6 ignored leaving memory location undisturbed special codice_6 value implemented reserved bit pattern using extra metadata bits associated belt item first iterations pipelined loop code drops group codice_13 belt using special codice_14 operation tells cpu many items drop cycle however many real items drop onto belt previous scheduled operations codice_14 drops enough additional codice_13 bring total number drops cycle requested amount steady state reached generally codice_13 generated way belt always expected number new items usual steady-state loop body operate codice_13 acting placeholders data n't ready operations scheduled previous iterations loop begin dropping results belt therefore starts new loop iteration real data items fewer placeholder codice_13 ordering rules simultaneous drops different-latency operations codice_14 ensure real results appear new iterations always occupy position codice_6 previous iterations operation use input belt number iterations meanwhile store operations loop body receive codice_6 values loop steady state reached therefore effect real results available storing thus loop body handles steady-state pipeline code includes appropriate codice_14 operations acts prologue code processing final elements pipeline generally finished loop deliberately execute extra iterations remaining scheduled operations time finish stored memory nearly operations side effects attempted invalid memory reads merely produce codice_24 value belt cause fault unless used store flow control operation pipeline nested loops mill treats loop almost like subroutine call automatic saves restores appropriate state belt scratchpad another improvement said open instruction-level parallelism mill instructions phased instructions may span several clock cycles hold 33 operations within instruction finishing occurs math operations first data rearrangements middle stores memory last also operations even multiple cores operate statically-predictable prioritized timings several versions mill processor development spanning tin low-end uses gold high-performance uses company estimates dual-core gold chips implemented 28 nm lithography may work 1.2 ghz typical thermal design power tdp 28watts performance 79 billion operations per second different versions mill intended different markets said different instruction set architectures different numbers execution units different pipeline timings thus different binaries accommodate compilers required emit specification recompiled executable binary recompiler supplied mill computing company way code distributed adapted specifics exact model pipeline binary coding etc development many tool sets processor designs may impractically costly ivan godard said mill plan develop software tools accept specification mill processor write software tools assembler compiler backend simulator verilog describing cpu demo video mill claimed show early versions software create assembler simulator bulk compiler said port llvm incomplete
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Computer architecture
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stormbringer video game stormbringer computer game written david jones released 1987 mastertronic mastertronic added dimension label originally released zx spectrum commodore 64 amstrad cpc msx version atari st published 1988 fourth final game magic knight series in-game music david whittaker magic knight finally returns home obtained second-hand time-machine tyme guardians end knight tyme however accident whilst travelling back two magic knights off-white knight dreaded stormbringer called storm cloud plans use destroy magic knight magic knight kill off-white knight without destroying process option find off-white knight merge gameplay takes form graphic adventure commands inputted via windimation menu-driven interface style previous two games spellbound knight tyme 1986 magic knight limited amount strength consumed performing actions moving screen screen well sapped various enemies stormbringer storm cloud spinning axes balls bounce around rooms avoided need player monitor magic knight strength avoid enemies means stormbringer gameplay closer arcade adventure feel spellbound rather much pure graphic adventure feel knight tyme previous two magic knight games characters magic knight interact help magic knight spellcasting abilities also important solving game puzzles including merge spell used finds off-white knight
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Computer architecture
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gh0st rat gh0st rat trojan horse windows platform operators ghostnet used hack many sensitive computer networks cyber spying computer program rat part name refers software ability operate remote administration tool ghostnet system disseminates malware selected recipients via computer code attached stolen emails addresses thereby expanding network allowing computers infected according infowar monitor iwm ghostnet infection causes computers download trojan known gh0st rat allows attackers gain complete real-time control computer controlled inspected hackers software even ability turn camera audio-recording functions infected computer capabilities enabling monitors see hear goes room
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Computer security
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activejpa activejpa open-source application framework written java object-relational mapping based java persistence api jpa strictly follow jsr 338 specification implements different design patterns technologies framework originated effort add behavior entities making act active records also implements different way proxying persistence operations transaction management intercepting operations validating logging caching using cross-cutting concerns decouple responsibilities retain modularity encapsulating aspects coding convention best way decrease number decisions made developers implementing technology activejpa require initial configuration datasource connection details database running persistence context supports specific unconventional aspects application well using annotations using type safe domain-specific language dsl database queries made using fluent object-oriented interface persistence operations transaction management interception validation logging caching vertically defined using cross-cutting concerns encapsulating responsibilities aspects improves performance scatters tangles code design implementation database access abstracted jdbc 4.2 specification supporting java 1.7 new jdbc features activejpa handles jta nested transactions global transactions transactions managed jdbc connection
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Databases
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copperegg copperegg corporation cloud computing systems management company based austin texas copperegg provinces family software service saas based cloud monitoring services public private cloud environments services include server monitoring website monitoring web application monitoring track system application performance alerts helps troubleshoot system application issues copperegg software products integrate public cloud providers amazon ec2 rackspace crn magazine included company list 10 hot new cloud startups watch 2011 2013 company recognized 2013 north america frost sullivan award new product innovation within cloud monitoring solutions company offers free version paid version software scott johnson eric anderson co-founded copperegg 2010 johnson previously co-founded thomas conrad networking hardware company acquired compaq computer corp. 1995 went co-found surgient networks 2000 chief technology officer anderson formerly software consultant held engineering roles austin-based centaur technology also worked johnson previous startup austin called storspeed inc copperegg name reference egg columbus columbus egg refers brilliant idea discovery seems simple easy fact also pays homage nikola tesla demonstrated principles rotating magnetic field induction motor demonstrating make copper egg stand end 2013-07-09 idera inc. announced acquisition copperegg corporation company stated acquisition would combine idera database monitoring copperegg server application performance management software give customers better visibility control environments saas-based management 2016 copperegg corporation web site ceases operational redirected idera inc. page copperegg monitoring software renamed 'uptime cloud monitor copperegg raised total 4.1m series funding backed austin-based silverton partners webb investment network investment fund former ebay executive maynard webb several private investors company raised initial round 2m funding july 2011 raised additional 2.1m ten months later may 2012 also hired new ceo bob quillin lead expansion push product build accelerate sales marketing copperegg addressing market according idc spending public cloud services growing compounding annual growth rate cagr 27.6 percent 21.5 billion 2010 72.9 billion 2015 451 group reports copperegg 200 paying customers company strategic partnerships companies amazon aws advanced technical partner rackspace solarwinds blitz io new economics technologies consumption models driving adoption cloud computing companies like copperegg developing products address new challenges go along lack visibility control copperegg provides collection saas-based cloud monitoring analytic solutions help companies accelerate delivery applications services across public private cloud environments company flagship product server monitoring solution called revealcloud originally launched july 2011 revealcloud provides real-time server monitoring linux windows freebsd mac os x servers 5 second on-screen performance updates visible saas application key unique features include less 10 second install web 2.0 graphical interface copperegg extended product introducing server application process monitoring update 2012 company launched second product july 2012 website monitoring solution called revealuptime revealuptime provides 15-second response time uptime health updates websites web applications web services tcp ports visible saas application performance metrics viewed together corresponding servers monitored revealcloud product october 2012 copperegg added management api provides open programmatic access automating orchestrating server monitoring website uptime analysis cloud infrastructure management update also added software-defined monitoring devops integration third-party automation tools chef puppet
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Distributed computing architecture
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l0phtcrack l0phtcrack password auditing recovery application originally produced mudge l0pht heavy industries used test password strength sometimes recover lost microsoft windows passwords using dictionary brute-force hybrid attacks rainbow tables one crackers tools choice although use old versions low price high availability initial version released spring 1997 application produced stake l0pht merged stake 2000 stake acquired symantec 2004 symantec later stopped selling tool new customers citing us government export regulations discontinued support december 2006 january 2009 l0phtcrack acquired original authors zatko wysopal rioux symantec l0phtcrack 6 announced 11 march 2009 source boston conference l0phtcrack 6 contains support 64-bit windows platforms well upgraded rainbow tables support l0phtcrack 7 released 30 august 2016 seven years previous release l0phtcrack 7 supports gpu cracking increasing performance 500 times previous versions
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Computer security
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ieee 802.1ae 802.1ae ieee mac security standard also known macsec defines connectionless data confidentiality integrity media access independent protocols standardized ieee 802.1 working group key management establishment secure associations outside scope 802.1ae specified 802.1x-2010 802.1ae standard specifies implementation mac security entities secy thought part stations attached lan providing secure mac service client standard defines security tag inside frame addition ethertype includes ieee 802.1ae macsec standard specifies set protocols meet security requirements protecting data traversing ethernet lans macsec allows unauthorised lan connections identified excluded communication within network common ipsec ssl macsec defines security infrastructure provide data confidentiality data integrity data origin authentication assuring frame comes station claimed send macsec mitigate attacks layer 2 protocols publishing history
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Internet protocols
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nintendo 3ds system software nintendo 3ds system software set updatable firmware versions software frontend nintendo 3ds family video game consoles updates downloaded via system internet connection allow nintendo add remove features software updates also include changes previous updates home menu graphical shell similar nintendo dsi menu wii u menu nintendo 3ds nintendo 2ds systems used launch software stored nintendo ds nintendo 3ds game cards applications installed sd card dsiware titles installed system ’ internal memory application icons set grid navigable touchscreen d-pad may re-arranged via drag-and-drop amount icons per column also changed 1 icon 6 menu display 120 application tiles upper screen special 3d animated logo displayed individual app well system information wireless signal strength date time battery life bottom screen application icons displayed also possible change screen brightness menu using home button users suspend current software running bring home menu allowing user launch certain multitasking applications internet browser miiverse similarly nintendo dsi menu upgradeable firmware game cards also hot-swapped menu power button prompts user either put console sleep mode shut april 25 2012 system update brought introduction folder system 60 folders created applications dragged top folder order move apps added folder using procedure 60 apps per folder title folder automatically created order creation 1 60 name also edited user first character title displayed folder icon apps inside folders receive streetpass spotpass notifications notification icon appear top folder june 20 2013 system update brought introduction save data backup feature feature allows user back save data downloadable nintendo 3ds software virtual console games creating backup save data allows users delete software sd card without losing save data backup created automatically restored user re-downloads software nintendo eshop total 30 save data backups stored time possible back save data retail versions nintendo 3ds software dsiware game boy advance software october 6 2014 9.0 system update brought revamp entire home menu exception multitasking applications also adding support themes allowing users customize home menu theme adds new backgrounds changes folder icons background music sound effects match theme new application called nintendo badge arcade released december 2014 japan november 2015 america europe allows yet customizing menu using badges pay-to-play crane game badges accessed/used via additional menu within home menu installed upon loading game placed removed like normal software icons/folders badges act shortcuts access specific pre-installed applications streetpass mii plaza nintendo 3ds camera built-in photo video recorder integrated media gallery photo editing functionality app uses system ’ two front-facing cameras take 3-d photos user-facing camera take regular 2-d photos photographs taken resolution 640 × 480 px vga 0.3 megapixels addition manual recording controls timers set take photo three ten seconds pressing take button means voice commands saying ok wishing take photo sd cards hold 3,000 photos photo data size vary number may reduced two may decrease various options filters available taking photos recording video addition normal mode low-light option useful taking photos recording video dark lighting conditions options include manual controls color type normal black white sepia negative solarize sharpness contrast brightness real-time photo filters also available including sparkle adds moving stars photo dream adds dream-like bright light photo pinhole lightens center screen darkens edges mystery adds random finish photo also special mode called merge takes photo user facing inner camera merges photo someone facing outer cameras december 7 2011 system update added ability record 3-d video along three special recording options interval shot allows sequences images recorded short-timed intervals create time-lapse photography frame pick edits still images together create stop motion animation montage lets user pause resume recording seamlessly videos recorded 10 minutes sd card ’ enough space available shooting time reduced however recording modes allow single video ten minutes long despite advanced predecessor software fewer features predecessor nintendo dsi camera even ’ enough free space sd card hold maximum combined total 3,000 photos videos nintendo 3ds sound built-in music player sound recorder supported audio codecs include mp3 audio .mp3 filename extensions aac audio .mp4 .m4a .3gp filename extensions audio files played sd card visualizations displayed upper screen music played console sleep mode using system ’ headphone jack using headphones included mic button button toggle play/pause skip next previous track set sound manipulation options available well several audio filters ten-second voice recordings also recorded edited audio filters manipulated modulation playback speed users may save modify 18 console ’ memory 180 sd card used throughout applications swapnote ’ streetpass function built-into app user streetpass ’ someone also streetpass enabled users exchange song data song ’ name artist album release year many times ’ played also compatibility chart users involved depending amount matching songs users score displayed ranging 0 100 latter compatible despite advanced predecessor software features fewer filters themes predecessor nintendo dsi sound nintendo 3ds uses friend code system much like original wii connect network exception one code necessary console makes much easier flexible players interact internet regardless nintendo network services require nintendo network id account order accessed nintendo eshop miiverse account shared wii u nintendo switch nintendo network administration team moderators staff remove inappropriate content services miiverse streetpass close proximity data exchange functionality allows game content exchanged nintendo 3ds systems using console background connectivity sleep mode nintendo 3ds automatically discover nintendo 3ds systems within range establish connection exchange content mutually played games transparently without requiring user input example user passes someone software initiate battle collect trophies application streetpass content stored one twelve data slots console using data slot nintendo 3ds users readily share exchange content multiple games time whenever connected regardless game card currently console spotpass always background network connectivity system automatically seek connect wireless network nodes wi-fi hotspots sending downloading information background sleep mode playing game spotpass also makes uses certified hotspots partners north america cloud united kingdom users able connect hotspots automatically free charge content downloaded via spotpass include full game application downloads firmware updates patches specific in-game content customized fit user preferences including opting altogether selected software application similar e-book reader considered use functionality automatically acquire magazine newspaper articles august 5 2013 system update introduced new feature called streetpass relay feature allows users exchange streetpass data passing certified nintendo zone hotspot last nintendo 3ds user pass hotspot streetpass enabled united states 29,000 street pass relay points europe set see approximately 30,000 day later feature also became available japan date streetpass relay points updated north america europe allow six users stored exchange instead one streetpass mii plaza streetpass application comes pre-installed every nintendo 3ds system players meet players miis streetpass online nintendo network interact application player mii customized hats earned mini games along short customizable message information new mii characters encountered system appear plaza gate player use play various mini games encountering mii characters meeting mii characters multiple times adds extra functionality personalized messages ability rate application comes three minigames minigames purchased optionally nintendo zone viewer built-in application detects makes use certified spotpass hotspots hotspot detected notification would appear system home menu application users could see game trailers game screenshots download game demos view information current upcoming nintendo 3ds titles player leaves hotspot app remains nintendo 3ds system although content accessed nintendo 3ds firmware run four different modes native_firm native running firmware nintendo 3ds software including home menu safe_mode_firm used safe mode applications system settings system updater twl_firm nintendo dsi native firmware used nintendo ds/dsi backward compatibility finally agb_firm game boy advance native firmware used run game boy advance virtual console games native_firm different new nintendo 3ds nomenclature firmware version shown 3ds system settings divided three parts first three numbers separated periods represent firmware version without eshop features one stored retail cartridges number dash represents improvements related eshop obtained via online update finally letter end represents region console possible letters china c europe australia e japan j south korea k taiwan americas u six regions exclusive firmware releases gaming platforms nintendo gaming platforms generation gaming platforms seventh generation
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Operating systems
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elite video game elite space trading video game written developed david braben ian bell originally published acornsoft bbc micro acorn electron computers september 1984 elite open-ended game model revolutionary 3d graphics led ported virtually every contemporary home computer system earned place classic genre maker gaming history game title derives one player goals raising combat rating exalted heights elite elite one first home computer games use wire-frame 3d graphics hidden line removal added graphics twitch gameplay aspects genre established 1974 game star trader another novelty inclusion dark wheel novella robert holdstock gave players insight moral legal codes might aspire game followed sequels 1993 1995 introduced newtonian physics realistic star systems seamless freeform planetary landings third sequel elite dangerous began crowdfunding 2012 launched 16 december 2014 following period semi-open testing elite proved hugely influential serving model games including grand theft auto eve online freelancer x series man sky non-acorn versions first published firebird imagineer subsequently frontier developments claimed game game frontier part back catalogue rights game owned david braben player initially controls character commander jameson though name changed time game saved player starts lave station 100 credits lightly armed trading ship cobra mark iii ships player encounters similarly named snakes reptiles credits accumulated number means include piracy trade military missions bounty hunting asteroid mining money generated enterprises allows player upgrade ship enhancements better weapons increased cargo capacity automated docking system extra energy bank game universe stars single planets space station orbit stars always separated interstellar distances effectively untraversable using ship sublight engines travel stars accomplished hyperspace jumps constrained within range limited fuel capacity maximum 7 light years ship hyperdrive sublight fuel capacity apparently infinite fuel replenished docking space station requires matching ship rotation station entering docking bay task avoided purchasing docking computer equipment upgrades include fuel scoop allows raw fuel skimmed surface stars described manual dangerous difficult activity practice fairly simple process far easier manually docking space station—and collecting free-floating cargo canisters escape capsules liberated destruction ships making hyperspace jump star systems antagonistic thargoid insect race may intercept player half way forcing player ship remain witch-space battle smaller invasion ships interrupted jump uses full journey fuel player may insufficient fuel subsequently jump nearby planet trapping witch-space must use escape capsule owned abort game reload extremely expensive one-shot galactic hyperspace upgrade permits travel eight galaxies game universe little practical difference different galaxies however versions necessary travel least second galaxy access game missions planetary layout galaxies different many players discovered trade runs closely positioned planets fortuitous economic combinations versions elite included several optional missions galactic navy one requires tracking destroying stolen experimental ship another involves transporting classified information thargoids home planet thargoid invasion ships best see succeed throughout duration mission involving multiple interplanetary jumps rewards differed depending mission cash gems esoteric hardware cloaking device according braben bell elite inspired range sources developers refer star wars hitchhiker guide galaxy original battlestar galactica influences braben also cites works larry niven jerry pournelle arthur c. clarke robert l. forward isaac asimov orson scott card thought much game content derived traveller tabletop role-playing game including default commander name jameson david braben denied several times developers met jesus college cambridge bell already working game acornsoft called freefall braben started writing game called fighter yet completed two projects sufficiently similar braben bell compared notes seeing star raiders atari 800 decided collaborate produce eventually became elite first approached thorn emi company rejection letter stated game complicated needed finishable 10 minutes three lives braben bell met acornsoft demo elite combat docking sequences impressed managing director david johnson-davies acornsoft executives company agreed publish finished game although company feared ambitious braben bell uncertain merits two developers instead one single game game took two years write started 3d arcade game without trading element written machine code using assembly language giving much care maximum compactness code last part added 3d radar display fitted last unused bytes computer original bbc version used novel split screen approach show four colours onscreen simultaneously upper two thirds screen displayed mode 4 lower part mode 5 subsequent electron version ran entirely mode 4 video chips 100 compatible therefore black white elite universe contains eight galaxies 256 planets explore due limited capabilities 8-bit computers worlds procedurally generated single seed number run fixed algorithm appropriate number times creates sequence numbers determining planet complete composition position galaxy prices commodities name local details text strings chosen numerically lookup table assembled produce unique descriptions planet carnivorous arts graduates means extra memory needed store characteristics planet yet unique fixed properties galaxy also procedurally generated first braben bell first intended 2 galaxies acornsoft insisted smaller universe hide galaxies mathematical origins however use procedural generation created problems number poorly located systems reached galactic hyperspace— 7 light years nearest neighbour thus trapping traveller braben bell also checked none system names profane removing entire galaxy finding planet named arse developers spend much time playing creation quality testing mostly performed acornsoft director marketing david johnson-davies also planned packaging marketing campaign time original bbc micro disk version uses non-standard disk-format copy protection relied specific osword 7f dfs opcodes intel 8271 floppy-disk controller directly access disk produce non-standard sector/track-layout causes issues legitimate customers use western digital 1770 disk-controller dfs roms third-party manufacturers watford electronics acorn subsequently released alternative versions bbc disks compatible wd1770 addition self-modifying code used part protection system created rob northen bbc disk-copy-protection also used superior software exile game acornsoft set motion large-scale publicity campaign commissioned presentational package game far elaborate normal acornsoft packaged elite box larger usual releases complete novella robert holdstock called dark wheel 64-page space trader flight training manual reference card ship identification poster flight training manual written style took rookie trader controls various aspects play dark wheel first novella included distribution video game original acornsoft version promised back cover sequel novella planned publication 1985 direct sequel ever written second novella imprint andy redman included ibm pc release elite plus apart set universe way connected original story marketing activities included £50,000 promotional budget acornsoft including television advertising launch party thorpe park theme park holding event video game almost unheard time competition among first achieve status elite story tells young starship pilot named alex ryder whose father jason killed merchant ship attacked notorious pirate trying understand avenge father death achieve iron ass space-trader term well armed- armoured spaceship alex encounters basics elite universe—including combat hyperdrive hyperspace deadly aliens called thargoids finally alex discovers truth father combat rank also acts acceptable face trading due female co-pilot elyssia fields alien species wanted several systems alex wants avenge father death must exercise caution tracking assassin trading commodities slowly improves arms armour ship competent using spaceship combat feels ready makes trade sure bring father killer alex also learns dark wheel takes join ranks first version game released bbc micro model b tape disk month two later acorn electron tape version released electron limitations meant several game features cut including thargoids suns neither bbc electron tape versions featured missions additionally original tape version electron contained bug stopped galactic hyperspace working acorn provided mail-in tape-replacement service upgrade v1.1 marked tape label fixed bug bbc b disk version referred classic elite would load new set ships every hyperspace jump space station launch meaning larger number ships available new disk version released superior software 1986 enhanced take advantage bbc micro model b successors including bbc micro model b+ master 128 computers optional 6502 second processor sideways ram fitted case game used modes 1 2 make colours available great commercial success bbc micro version prompted bidding war rights publish elite formats british telecom software arm telecomsoft eventually eventually ported virtually every contemporary home computer system including amiga atari st apple ii amstrad cpc commodore 64 zx spectrum msx tatung einstein ibm pc compatible console version released 1991 nintendo entertainment system nes version released exclusively europe according developers n't released north america could find publisher game north america versions slightly altered gameplay characteristics number missions offered player contemporary versions home computers based 6502 microprocessor ported either bell bell braben commodore 64 conversion introduced trumbles creatures based tribbles docking computer activated commodore 64 version versions musical rendition blue danube waltz played nod space docking sequence stanley kubrick 1968 film music arranged david dunn zx spectrum version programmed torus included supernova mission found version amstrad cpc conversion port zx version fewer ships platforms lacking anaconda transport along minor differences missions titles according lead programmer 16 bit amiga/atari st msx conversions rob nicholson access source code contractual issues write blind ship shapes procedural generation code galaxies elite plus released dos 1991 whereas original elite 1987 pc used cga graphics elite plus upgraded take advantage ega vga mcga coded entirely assembly language chris sawyer later wrote rollercoaster tycoon elite plus ninth galaxy reached hyperspacing witch space elite plus published microplay software acorn archimedes version arcelite 1991 written warren burch clive gringras regarded stuff magazine best conversion original game added intelligent opponents engage private battles police take active interest protecting law well gameplay enhancements version also exploited modern hardware using polygon mesh graphics place wire-frames game world longer seems centred around player freighter fleets escorts go business pirate formations patrol lawless systems looking cargo loot mining ships often found breaking asteroids mineral content unlike mythical generation ships original rare occurrences non-pirate entities mentioned manual really found archimedes version geometric formations space beacons hermits living among asteroids abandoned ships towed police although dredgers generation ships confirmed exist archimedes elite archimedes version elite originally written space trading game called trojan however obvious similarities eventually meant avoid potential lawsuit trojan become official elite conversion arcelite one number games released free icon bar website 2006 versions feature new title archangel player earn substitutes rank commander archangel reached undertaking special mission destroy space station system invaded thargoids player reward completing mission receive title archangel obtain device capable emulating anti-ecm broadcast elite received positive reviews launch bbc micro version eventually sold 107,898 copies game popularity became national phenomenon uk reports airing channel 4 elsewhere elite firebird best-selling commodore game late 1987 bell estimates approximately 600,000 copies eventually sold platforms combined frontier developments elite page states numbers around million units elite technical breakthroughs reportedly amazed bbc micro developers sophie wilson calling game could n't written many players found gameplay difficult unfamiliar however game controversial micro user devoted april 1985 letter column readers debating review game beebug magazine 1984 david fell called elite best game ever bbc micro personal computer games shingo sugiura said elite vast complex absorbing 've got bulging red eyeballs staying early hours n't care 'm going continue playing ranked elite ... least competent ... even average ... buy john cook wrote december 1984 issue micro adventurer masterpiece difficult describe within existing parameters standards elite excellent game certainly top three year bbc standards simply best game ever written machine crash magazine said spectrum version elite one imaginative ever designed run home computer gave score 92 time best-seller gallup charts game number 16 sinclair top 100 speccy games 1992 voted number 7 sinclair readers top 100 games time 1993 voted 9th best game time readers retro gamer magazine article scheduled special sinclair tribute issue similarly zzap 64 gave commodore 64 version 97 stating brilliant game blasting trading certainly best game 've seen year 1985 amiga version 98 1989 1984 elite received golden joystick award best original game 1985 game awarded best game overall year readers crash magazine elite ranked 14 top game time next generation 1996 12 ign 2000 top 25 pc games time list 3 influential video game ever times online 2007 6 greatest game stuff magazine 2008 1 top retro game retro gamer 2004 1 best game 1980s next generation 2008 game retrospectively awarded 10/10 multi-format magazine edge —together 2 games— exhibited places london science museum game exhibition organised toured barbican art gallery elite also featured game pong oblivion 50 greatest video games time authors simon byron ste curran david mccarthy 1991 pc format placed elite plus list 50 best computer games time editors called classic game mixes solid 3d space combat trading create universe spend many happy half-hour bushwhacking dastardly thargoids elite often regarded yardstick subsequent space trading games measured since release elite credited title defined modern space flight simulation genre significant source inspiration later games genre well influential upon gaming whole interviews senior producers ccp games cited elite one inspirations acclaimed mmorpg eve online developers jumpgate evolution battlecruiser 3000ad infinity quest earth hard truck apocalyptic wars flatspace likewise credited elite source inspiration similar praise bestowed elsewhere media years named one influential games history credited first truly open-ended open world game opening door future online persistent worlds second life world warcraft eve online elite one popularly requested games remade arguing still best example genre date recent titles—including immediate sequel—not rising level november 1999 game 15th birthday ian bell released many binaries source code several versions original game website dispute arose bell david braben regarding bell decision make available versions original elite dispute since ended various versions became available bell site late 1980s variant commercial bbc micro elite release created angus duggan disassembling modifying 6502 code existing many extra features originally titled elite iii known elite minimise confusion includes many ship types ship types flyable player begins less capable adder cargo delivery missions extra equipment items numerous gameplay improvements elite released publicly 1997 like original game downloaded free ian bell web site played emulation many attempts develop clones elite made abandoned completion otherwise failed come fruition open source oolite notable exception another successful adaptation 1337 meaning elite leetspeak developed jose maria enguita oric machines 2010 oldschool gaming game year award contrasting conversions around 1999 christian pinder developed elite new kind modern pc port original bbc micro version achieved faithful port reverse-engineering original assembly written bbc micro version recreating platform neutral c code variant david braben request version withdrawn distribution 2003 september 2014 elite 30th birthday ian bell blessed elite new kind re-released free website since elite new kind also distributed version 1.1 christian pinder source code mirror hosted github 20 october 2013 internet archive started offer elite zx spectrum version online playing browser via mess emulation three official sequels created 1993 elite iii 1995 produced braben company frontier developments third sequel elite dangerous conceived 1998 provisionally titled elite 4 successfully crowdfunded initially kickstarter campaign late 2012 released december 2014 bell limited involvement first sequel involved production second frontier games considerable advance original elite filled 3d graphics missions complex economy time player confined orbit could land explore mine planets number flyable ships greatly increased new political backstory introduced enabling player gain ranks competing interstellar empires frontier elite ii appeared commodore amiga atari st ibm pc whilst frontier first encounters released ibm pc two frontier games significantly flawed number respects games many bugs first encounters particular due apparently published incomplete state first encounters extensively patched reissued finally withdrawn sale followed lawsuit brought gametek david braben two games employed realistic flight model based newtonian mechanics rather original arcade-style engine realistic many players also found frustratingly difficult particularly combat space trading games since elite stuck arcade-style flight model ships behave though flying atmosphere elite dangerous added multiplayer extended use procedural generation allowing players fly survey every non-atmospheric planet every size galaxy containing billions stars elite dangerous also offers newtonian flight model well arcade one player able choose using 'flight assist
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Computer architecture
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isis operating system isis short intel system implementation supervisor operating system early intel microprocessors like 8080 originally developed ken burgett new management bill davidow intel microprocessor development system starting 1975 later adopted isis-ii systems floppy drives communication user terminal-like user interface somewhat cp/m-like even program interface point view file opening program sends name file gets back handle device name entered pair colons codice_1 codice_2 floppies codice_3 printer etc. diskette one directory subdirectories isis-ii distributed part intel microprocessor development system includes standard operating system commands copy delete dir rename format debugging software assembler linker debugger external debugging developed device two editors one aedit contains editing macros support file editing provided directly diskette .bak file always created editor credit isis-ii needed least 32 kilobytes ram 8080/8085 cpu maximum address space 64 kilobytes mds-800 series-ii monitor occupied f800h ffffh floppy disk format 8-inch single-sided 250 kb single-sided single-density fm 500 kb single-sided double-density mmfm isis-pds also software media incompatible unique came 720 kb dsdd 5¼-inch floppies intel personal development system ipds-100 isis-iv operating system another incompatible even intel development systems ran imdx-430 series-iv network development system-ii intel asm80 plm-80 basic-80 cobol-80 fortran-80 available isis-ii asm86 asm48 asm51 available well following list commands supported isis-ii console
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Operating systems
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turboprint turboprint closed source printer driver system linux amigaos morphos supports number printers n't yet free driver fuller printer functionality printer models recent versions integrates cups printing system
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Operating systems
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p2ptv p2ptv refers peer-to-peer p2p software applications designed redistribute video streams real time p2p network distributed video streams typically tv channels world may also come sources draw applications significant potential make tv channel globally available individual feeding stream network peer joining watch video relay peer viewers allowing scalable distribution among large audience incremental cost source p2ptv system user downloading video stream simultaneously also uploading stream users thus contributing overall available bandwidth arriving streams typically minutes time-delayed compared original sources video quality channels usually depends many users watching video quality better users architecture many p2ptv networks thought real-time versions bittorrent user wishes view certain channel p2ptv software contacts tracker server channel order obtain addresses peers distribute channel contacts peers receive feed tracker records user address given users wish view channel effect creates overlay network top regular internet distribution real-time video content need tracker also eliminated use distributed hash table technology applications allow users broadcast streams whether self-produced obtained video file tv tuner card video capture card lots commercial p2ptv applications developed china tvuplayer pplive qqlive ppstream majority available applications broadcast mainly asian tv stations exception tvuplayer carries number north american stations including cbs spike tv fox news applications distribute tv channels without legal license utilization p2p technology particularly popular view channels either available locally available paid subscription case sports channels distributing links pirated p2ptv feeds u.s.-based web site result u.s. government seizing web site several p2ptv aggregation sites prior super bowl xlv january 2009 14,000 p2p channels ppstream commercial p2ptv applications outside china abroadcasting usa zattoo switzerland/usa octoshape denmark livestation uk
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Distributed computing architecture
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pentium fdiv bug pentium fdiv bug computer bug affecting floating point unit fpu early intel pentium processors bug processor might return incorrect binary floating point results dividing number bug discovered 1994 professor thomas r. nicely lynchburg college intel attributed error missing entries lookup table used floating-point division circuitry severity fdiv bug debated though rarely encountered users byte magazine estimated 1 9 billion floating point divides random parameters would produce inaccurate results flaw intel initial handling matter heavily criticized tech community december 1994 intel recalled defective processors january 1995 intel announced pre-tax charge 475 million earnings ostensibly total cost associated replacement flawed processors sweeney robertson tocher srt division algorithm used affected pentium chips implemented programmable logic array 2,048 cells 1,066 cells populated one five values buggy chips five cells contained value +2 missing instead returning 0 thomas nicely professor mathematics lynchburg college written code enumerate primes twin primes prime triplets prime quadruplets nicely noticed inconsistencies calculations june 13 1994 shortly adding pentium system group computers unable eliminate factors programming errors motherboard chipsets etc october 19 1994 october 24 1994 reported issue intel according nicely contact person intel later admitted intel aware problem since may 1994 flaw discovered tom kraljevic purdue university co-op student working intel hillsboro oregon testing fpu new p6 core first used pentium pro october 30 1994 nicely sent email describing error discovered pentium floating point unit various contacts requesting reports testing flaw 486-dx4s pentiums pentium clones flaw pentium fpu quickly verified people around internet became known pentium fdiv bug fdiv x86 assembly language mnemonic floating-point division one example found division result returned pentium 61 parts per million story first appeared press november 7 1994 article electronic engineering times intel fixes pentium fpu glitch alexander wolfe story subsequently picked cnn segment aired november 21 1994 brought widespread public prominence publicly intel acknowledged floating-point flaw claimed serious would affect users intel offered replace processors users could prove affected however although independent estimates found bug little importance would negligible effect users caused great public outcry companies like ibm whose ibm 5x86c microprocessor competed time intel pentium line joined condemnation december 20 1994 intel offered replace flawed pentium processors basis request response mounting public pressure although turned small fraction pentium owners bothered get chips replaced financial impact company significant january 17 1995 intel announced pre-tax charge 475 million earnings ostensibly total cost associated replacement flawed processors defective chips later turned key rings intel 1995 article science describes value number theory problems discovering computer bugs gives mathematical background history brun constant problem nicely working discovered bug problem occurs models original pentium processor bug existed pentium family processors clock speed less 120 mhz affected models intel processor frequency id utility checks presence bug ten affected processors listed 39 s-specs processors listed intel processor specification finder web page intel 80486 overdrive pentium overdrive models also known exhibit fdiv bug well f00f bug presence bug checked manually performing following calculation application uses native floating point numbers including windows calculator microsoft excel windows 95/98 correct value converted hexadecimal value used processor 4,195,835 0x4005fb 3,145,727 0x2fffff 5 0x4005fb triggers fault fpu control logic result value returned flawed pentium processor certain situations incorrect beyond four digits users check processor issue using device manager device manager users expand system devices locate click numeric data processor click properties button new properties window appears click settings tab. br processor fdiv issue following message seen computer numeric data processor passed diagnostic tests appears working properly otherwise following message shall appear numeric processor computer sometimes compute inaccurate results dividing large numbers options provided bottom settings tab always use use passes diagnostics never use users run codice_1 command included windows nt 3.51 nt 4.0 2000 xp server 2003 computer needs restarted changes take effect codice_1 utility deprecated included current versions windows command-syntax nowiki pentnt -c -f -o /nowiki
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Computer architecture
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sql server agent sql server agent component microsoft sql server schedules jobs handles automated tasks runs windows service start automatically system boots started manually typical system tasks performed include scheduling maintenance plans backups handling reporting services subscriptions performing log shipping sub-tasks backup copy restore check user tasks scheduling t-sql command line statement also common sqlagent support operators alerts administrators notified e.g email
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Databases
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closing loop closing loop company offers closed loop service mobile phones dutch social enterprise based amsterdam netherlands founded aim reduce electronic waste e-waste offering users sellers phones way make device material-neutral waste free company pays people emerging markets collect scrap phones phones recycled behalf closing loop ’ customers proposition works one one basis customer ’ phone ‘ offset ’ recycling broken phone known customers t-mobile kpmg city utrecht rabobank dutch national government closing loop buys collects 'end-of-life scrap phones african countries known places many used phones europe us get second life waste closing loop collects recycled europe way closing loop turns scrap phones valuable resources income people developing countries goal prevent mobile phones ending dump sites create sustainable telecom industry time closing loop saved 2.2 million mobile phones dump africa gave 145,000 mobile phones second life mobile phones bought informal local collector networks date closing loop helped 2,000 people africa earn additional income safe employment social enterprise sees e-waste opportunity opportunity source companies responsibly sourced metals make industries like telecom circular closing loops create income people emerging markets aims contribute circular economy sustainable development goals closing loop founded 2012 joost de kluijver joost started ngo make electronic industry aware impact e-waste although recognised e-waste major problem industry clearly needed awareness topic e-waste joost team therefore took initiative showed metals inside broken mobile phones still value contain gold silver copper recyclable metals closing loop set network collectors african countries 2015 first container filled mobile phones shipped ghana europe proper recycling end lifespan scrap mobile phones often dumped become hazard environment human health example landfills like agbogbloshie e-waste dumped people try make living burning electronics extract metals fumes released toxic
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Computer security
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slax slax livecd linux distribution based debian developed tomáš matějíček packages added apt package manager prepared modules tagline slax refers pocket operating system one main benefits slax distribution ease customization additional software added removed using slax modules traditional package manager debian apt required load additional software slax modules completely self-contained however apt fully supported users also modify default cd image usb drive installation customize packages available distribution boot slax also allows debian packages converted slax modules slax modules compressed read-only squashfs file system images compressed lzma compressor various modules stacked together build complete slax root directory supplemental writable layer tmpfs file system put top stack implement write functionality stackable file system choice changed slax versions 5 unionfs 6 aufs module file name extension changed .mo .sb slax releases slax 3 known slackware-live latest version slax 9.9.1 five editions slax 5 fluxbox window manager option editions except frodo slax 6 offered single version completely relies modules additional packages extra features version 6 modules based lzma compression compatibility initially provided obsolete .mo modules used slax version 5 recent .lzm modules version 6 changes linux kernel versions sub-version releases slax 6 however .mo modules slax 5 considered obsolete module package compiled compatibility linux kernel currently use slax version 7 announced developer blog integrated newly refreshed slax website slax 7 supports 64-bit 32-bit architectures according download page available 50 languages also features stripped version kde 4 new wallpaper new module system november 2017 developer announced release version 9 latest edition heavily rewritten based debian relies apt add packages default builds 32-bit 64-bit contain fluxbox window manager terminal chromium web browser leafpad text editor calculator pcmanfm file manager wicd network manager
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Operating systems
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risk-based authentication authentication risk-based authentication non-static authentication system takes account profile agent requesting access system determine risk profile associated transaction risk profile used determine complexity challenge higher risk profiles leads stronger challenges whereas static username/password may suffice lower-risk profiles risk-based implementation allows application challenge user additional credentials risk level appropriate
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Computer security
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levels identity security security features governing security identity divided three levels security i.e level 1 security l1s overt level 2 security l2s covert level 3 security l3s forensic three levels security combination provide comprehensive security coverage identities related documents ensure validity authenticity typically used protect identity information crucial documents identity cards driving licenses passports ensure originality accuracy identities represent diagram illustrates different levels security ensure complete security coverage identity
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Computer security
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jewels darkness jewels darkness formerly middle-earth trilogy trilogy text adventure games level 9 individual games initially released separately 1983 featured themes inspired books j. r. r. tolkien became known middle-earth trilogy 1986 three games revised expanded rereleased together compilation legal reasons references middle-earth removed trilogy retitled jewels darkness games featured simple static graphics expanded version original adventure crowther woods similar structure previous game player must defeat dark lord continuation previous game following defeat dark lord player must explore tower looking treasure computer gaming world stated compilation claim games significantly revised incorporate latest innovative techniques false described puzzles illogical commodore version graphics crude like parser standard previous firebird text adventures graphics colourful 're great works art location descriptions scenarios always struck good enough br zzap issue sept. 1986
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Computer architecture
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windows mobility center windows mobility center component microsoft windows introduced windows vista centralizes information settings relevant mobile computing mobility center displayed device settings pertinent mobile devices first shown windows hardware engineering conference 2004 based activity center user interface design originated microsoft abandoned windows neptune project slated inclusion windows vista known codename longhorn windows mobility center user interface consists square tiles contain information settings related component audio settings battery life power schemes display brightness wireless network strength status tiles appear within interface depend hardware system device drivers windows mobility center located windows control panel also launched pressing keys windows vista 7 default wmc inaccessible desktop computers limitation bypassed one modifies windows registry windows mobility center extensible original equipment manufacturers customize interface additional tiles company branding though supported microsoft possible individual developers create tiles interface well
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Operating systems
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apple a8x apple a8x 64-bit arm-based system chip soc designed apple inc. manufactured tsmc first appeared ipad air 2 announced october 16 2014 variant a8 inside iphone 6 family smartphones apple states 40 cpu performance 2.5 times graphics performance predecessor apple a7 a8x three cores clocked 1.5 ghz powerful gpu compared a8 contains 3 billion transistors extra 100 mhz additional core a8x performs around 13 better single threaded 55 better multithreaded operations a8 inside iphone 6 iphone 6 plus comparison a8 shows a8x uses metal heat spreader a8 n't use package package configuration included ram a8 similar older x variants a5x a6x designed instead a8x ipad air 2 uses external 2 gb ram module first apple a8x reported semi-custom gpu a8x uses 8-cluster gpu based imagination technologies powervr series 6xt architecture officially largest implementation rogue 6-cluster design indicating apple made customizations design order provide higher performance gpu referred gxa6850 denoting apple customization a8x branch predictor claimed infringe 1998 patent october 14 2015 district judge found apple guilty infringing u.s. patent table based data speculation circuit parallel processing computer apple a7 a8 processors patent owned wisconsin alumni research foundation warf firm affiliated university wisconsin july 24 2017 apple ordered pay warf 506 million patent infringement apple filed appellate brief october 26 2017 u.s. court appeals federal circuit argued apple infringe patent owned wisconsin alumni research foundation september 28 2018 ruling overturned appeal award thrown u.s. federal circuit court appeals patent expired december 2016
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Computer architecture
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word-sense induction computational linguistics word-sense induction wsi discrimination open problem natural language processing concerns automatic identification senses word i.e meanings given output word-sense induction set senses target word sense inventory task strictly related word-sense disambiguation wsd relies predefined sense inventory aims solve ambiguity words context output word-sense induction algorithm clustering contexts target word occurs clustering words related target word three main methods proposed literature underlying hypothesis approach words semantically similar appear similar documents similar context windows similar syntactic contexts occurrence target word corpus represented context vector context vectors either first-order vectors directly represent context hand second-order vectors i.e. contexts target word similar words tend co-occur together vectors clustered groups identifying sense target word well-known approach context clustering context-group discrimination algorithm based large matrix computation methods word clustering different approach induction word senses consists clustering words semantically similar thus bear specific meaning lin ’ algorithm prototypical example word clustering based syntactic dependency statistics occur corpus produce sets words discovered sense target word clustering committee cbc also uses syntactic contexts exploits similarity matrix encode similarities words relies notion committees output different senses word interest approaches hard obtain large scale many domain languages main hypothesis co-occurrence graphs assumes semantics word represented means co-occurrence graph whose vertices co-occurrences edges co-occurrence relations approaches related word clustering methods co-occurrences words obtained basis grammatical collocational relations hyperlex successful approaches graph algorithm based identification hubs co-occurrence graphs cope need tune large number parameters deal issue several graph-based algorithms proposed based simple graph patterns namely curvature clustering squares triangles diamonds squat++ balanced maximum spanning tree clustering b-mst patterns aim identifying meanings using local structural properties co-occurrence graph randomized algorithm partitions graph vertices iteratively transferring mainstream message i.e word sense neighboring vertices chinese whispers applying co-occurrence graphs approaches shown achieve state-of-the-art performance standard evaluation tasks
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Computational linguistics
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openbase openbase sql relational database server software originally developed openstep platform first released 1991 openbase available today several platforms although bulk users mac os x system supports common access methods via jdbc c however optimized use conjunction variety macintosh-based development tools like webobjects realbasic omnis studio
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Databases
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gntp genealogy network transfer protocol gntp unfinished protocol peer-to-peer genealogy network completed resource constraints idea allow genealogists share gedcom files much way music files distributed peer-to-peer networks
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Internet protocols
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jinja template engine jinja web template engine python programming language licensed bsd license created armin ronacher similar django template engine provides python-like expressions ensuring templates evaluated sandbox text-based template language thus used generate markup well sourcecode jinja template engine allows customization tags filters tests globals also unlike django template engine jinja allows template designer call functions arguments objects jinja flask default template engine also used ansible features jinja jinja like smarty also ships easy-to-use filter system similar unix pipeline small example template file example.html.jinja templating code produces html string
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Web technology
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u3 software u3 joint venture sandisk m-systems producing proprietary method launching windows software special usb flash drives flash drives adhering u3 specification termed u3 smart drives u3 smart drives come preinstalled u3 launchpad looks similar windows os start menu controls program installation applications comply u3 specifications allowed write files registry information host computer must remove information flash drive ejected customizations settings instead stored application flash drive microsoft sandisk created successor called startkey sandisk began phasing support u3 technology late 2009 u3 flash drive presents host system usb hub cd drive standard usb mass storage device attached u3 launchpad launchu3.exe windows program manager preinstalled every u3 smart drive u3 launchpad automatically starts insertion u3 enabled device fully u3 compliant application programmed clean data local machine must also packaged u3 special program format u3 applications run u3 device u3 programs downloaded u3 website places applications include opera skype need installed computer u3 application programming interfaces apis allow u3 programs lower-level access usb flash drive query drive letter u3 apis primarily allow developers choose use power u3 control application handles things like device removal saves data back drive configuration documents latest version u3 launchpad supports windows 2000 service pack 4 windows xp windows vista windows 7 windows 8 data accessed using os capable reading usb mass storage devices unless u3 device password-protected early versions u3 launchpad software vista compatibility issues specifically sandisk cruzer titanium series device numbers 2.17 2.18 2.19 2.20 although problem could eliminated updating launcher software prior sandisk updated launcher software released microsoft supported u3 releasing update vista information building u3 compliant applications u3 software development kit available registered developers official u3 website individuals must register company download sdk participate forums applications require installation steps order run easily utilize u3 little modification taking steps either modify host systems files registry undoing changes application terminates wizard packages distribution files creates special manifest file provided may 2009 software development kit longer available u3.com website longer available reformatting drive remove software hidden system folder virtual cd-rom drive removed reformatting presented host system physical device attached usb hub official u3 launchpad removal software available u3 website disabled virtual cd drive device leaving usb mass storage device active u3 usb hub controller point remaining software removed subsequent format performed removal software u3_tool another option includes ability remove virtual cd-rom drive well ways reconfigure user liking numerous criticisms made u3 platform criticisms
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Operating systems
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havoc pennington robert sanford havoc pennington born c. 1976 american computer engineer entrepreneur known free software movement due work hal gnome metacity gconf d-bus havoc pennington graduated university chicago 1998 graduation worked red hat desktop manager/engineer nine years ending 2008 also founded project freedesktop.org 2000 promoted idea gnome online desktop 2007 time led development 2006–2009 mugshot project 2008 june 2011 worked consumer product startup company litl hardware proprietary software services 2011 2015 worked typesafe lightbend 2017 cofounded tidelift seeks improve ecosystem around open source software providing support professional teams using open source helping maintainers build sustainable businesses around projects
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Operating systems
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imsi-catcher international mobile subscriber identity-catcher imsi-catcher telephone eavesdropping device used intercepting mobile phone traffic tracking location data mobile phone users essentially fake mobile tower acting target mobile phone service provider real towers considered man-in-the-middle mitm attack 3g wireless standard offers risk mitigation due mutual authentication required handset network however sophisticated attacks may able downgrade 3g lte non-lte network services require mutual authentication imsi-catchers used united states countries law enforcement intelligence agencies use raised significant civil liberty privacy concerns strictly regulated countries german strafprozessordnung stpo code criminal procedure countries encrypted phone data traffic weak encryption thus rendering imsi-catcher unnecessary virtual base transceiver station vbts device identifying international mobile subscriber identity imsi nearby gsm mobile phone intercepting calls patented first commercialized rohde schwarz 2003 device viewed simply modified cell tower malicious operator 4 january 2012 court appeal england wales held patent invalid obviousness gsm specification requires handset authenticate network require network authenticate handset well-known security hole exploited imsi catcher imsi catcher masquerades base station logs imsi numbers mobile stations area attempt attach imsi-catcher allows forcing mobile phone connected use call encryption a5/0 mode use easily breakable encryption a5/1 a5/2 mode making call data easy intercept convert audio 3g wireless standard mitigates risk enhanced security protocol due mutual authentication required handset network removes false base station attack gsm sophisticated attacks 3g lte may able downgrade non-lte network services require mutual authentication body-worn imsi-catchers target nearby mobile phones advertised law enforcement agencies us imsi-catchers often deployed court order without search warrant lower judicial standard pen register trap-and-trace order preferred law enforcement also used search rescue operation missing persons police departments reluctant reveal use programs contracts vendors harris corporation maker stingray kingfish phone tracker devices uk first public body admit using imsi catchers scottish prison service though likely metropolitan police service using imsi catchers since 2011 every mobile phone requirement optimize reception one base station subscribed network operator accessible always choose one strongest signal imsi-catcher masquerades base station causes every mobile phone simulated network operator within defined radius log help special identity request able force transmission imsi imsi-catcher subjects phones vicinity man-in-the-middle attack appearing preferred base station terms signal strength help sim simultaneously logs gsm network mobile station since encryption mode chosen base station imsi-catcher induce mobile station use encryption hence encrypt plain text traffic mobile station pass base station indirect connection mobile station via imsi-catcher gsm network reason incoming phone calls generally patched mobile station gsm network although modern versions devices mobile patch-through solutions order provide functionality false base station attacks prevented combination key freshness integrity protection signaling data authenticating serving network provide high network coverage umts standard allows inter-operation gsm therefore umts also gsm base stations connected umts service network fallback security disadvantage allows new possibility man-in-the-middle attack assignment imsi catcher number difficulties preliminary research done trying detect frustrate imsi-catchers one project osmocom open source mobile station software special type mobile phone firmware used detect fingerprint certain network characteristics imsi-catchers warn user device operating area firmware/software-based detection strongly limited select outdated gsm mobile phones i.e motorola longer available open market main problem closed-source nature major mobile phone producers application android imsi-catcher detector aimsicd developed detect circumvent imsi-catchers stingray silent sms technology stationary network imsi-catcher detectors also developed several apps listed google play store imsi catcher detector apps include snoopsnitch cell spy catcher gsm spy finder 100,000 500,000 app downloads however apps limitations access phone underlying hardware may offer minimal protection
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Computer security
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ibm thinkpad 760 ibm thinkpad 760 notebook computer introduced 1995 ibm corporation market part thinkpad 700-series succeeded 1998 thinkpad 770 series 760 -series ibm thinkpad available time production state art notebook available public ibm featured advanced mobile technology came standard latest hardware available laptops notebooks time used intel pentium processor utilized edo ram soldered onto motherboard prevent booting without usable ram ability easily exchange critical hardware components hard drive battery option hardware fit ultrabay ram model also featured unique keyboard could slide upward back side rails flip towards user provide ergonomic feel note model number signifies machine updated chassis provision fitment cd-rom drive using adapter plate internal floppy disk drive models without n't officially come updated chassis
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Computer architecture
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p5 microarchitecture first pentium microprocessor introduced intel march 22 1993 dubbed p5 microarchitecture fifth generation intel first superscalar ia-32 microarchitecture direct extension 80486 architecture included dual integer pipelines faster floating-point unit wider data bus separate code data caches features reduced address calculation latency 1996 pentium mmx technology often simply referred pentium mmx introduced basic microarchitecture complemented mmx instruction set larger caches enhancements p5 pentium competitors included motorola 68060 powerpc 601 well sparc mips alpha microprocessor families also used superscalar in-order dual instruction pipeline configuration time intel larrabee multicore architecture project uses processor core derived p5 core p54c augmented multithreading 64-bit instructions 16-wide vector processing unit intel low-powered bonnell microarchitecture employed early atom processor cores also uses in-order dual pipeline similar p5 intel discontinued p5 pentium processors downgraded entry-level product since pentium ii debuted 1997 1999 favor celeron processor also replaced 80486 brand p5 microarchitecture designed santa clara team designed 386 486 design work started 1989 team decided use superscalar architecture on-chip cache floating-point branch prediction preliminary design first successfully simulated 1990 followed laying-out design time team several dozen engineers design taped transferred silicon april 1992 point beta-testing began mid-1992 p5 team 200 engineers intel first planned demonstrate p5 june 1992 trade show pc expo formally announce processor september 1992 design problems forced demo cancelled official introduction chip delayed spring 1993 john h. crawford chief architect original 386 co-managed design p5 along donald alpert managed architectural team dror avnon managed design fpu vinod k. dham general manager p5 group p5 microarchitecture brings several important advancements preceding i486 architecture pentium designed execute 100 million instructions per second mips 75 mhz model able reach 126.5 mips certain benchmarks pentium architecture typically offered twice performance 486 processor per clock cycle common benchmarks fastest 80486 parts slightly improved microarchitecture 100 mhz operation almost powerful first-generation pentiums amd am5x86 roughly equal pentium 75 regarding pure alu performance early versions 60–100 mhz p5 pentiums problem floating-point unit resulted incorrect predictable results division operations bug discovered 1994 professor thomas nicely lynchburg college virginia became known pentium fdiv bug caused embarrassment intel created exchange program replace faulty processors soon afterwards discovered bug could allow malicious program crash system without special privileges f00f bug fortunately operating systems able implement workarounds prevent crashes 60 66 mhz 0.8 µm versions p5 pentium processors also time high heat production due 5 v operation p54c used 3.3 v significantly lower power draw 51 quadratic relationship p5 pentiums used socket 4 p54c started socket 5 moving socket 7 later revisions desktop pentiums p54cs onwards used socket 7 pentium intel primary microprocessor personal computers mid-1990s original design reimplemented newer processes new features added maintain competitiveness well address specific markets portable computers result several variants p5 microarchitecture first pentium microprocessor core code-named p5 product code 80501 80500 earliest steppings q0399 two versions specified operate 60 mhz 66 mhz respectively first implementation pentium used traditional 5-volt power supply descended usual ttl logic compatibility requirements contained 3.1 million transistors measured 16.7 mm 17.6 mm area 293.92 mm fabricated 0.8 µm bicmos process 5-volt design resulted relatively high energy consumption operating frequency compared later models p5 followed p54c 80502 also known pentium-s versions specified operate 75 90 100 mhz using 3.3 volt power supply first pentium processor operate 3.3 volts reducing energy consumption employed internal clock multiplier let internal circuitry work higher frequency external address data buses complicated cumbersome increase external frequency due physical constraints also allowed two-way multiprocessing integrated local apic well new power management features contained 3.3 million transistors measured 163 mm fabricated bicmos process described 0.5 µm 0.6 µm due differing definitions p54c followed p54cqs operated 120 mhz fabricated 0.35 µm bicmos process first commercial microprocessor fabricated 0.35 µm process transistor count identical p54c despite newer process identical die area well chip connected package using wire bonding allows connections along edges chip smaller chip would required redesign package limit length wires edges chip would away pads package solution keep chip size retain existing pad-ring reduce size pentium logic circuitry enable achieve higher clock frequencies p54cqs followed p54cs operated 133 150 166 200 mhz contained 3.3 million transistors measured 90 mm fabricated 0.35 µm bicmos process four levels interconnect p24t pentium overdrive 486 systems released 1995 based 3.3 v 0.6 µm versions using 63 83 mhz clock since used socket 2/3 modifications made compensate 32-bit data bus slower on-board l2 cache 486 motherboards therefore equipped 32 kb l1 cache double pre-p55c pentium cpus p55c 80503 developed intel research development center haifa israel sold pentium mmx technology usually called pentium mmx although based p5 core featured new set 57 mmx instructions intended improve performance multimedia tasks encoding decoding digital media data pentium mmx line introduced october 22 1996 new instructions worked new data types 64-bit packed vectors either eight 8-bit integers four 16-bit integers two 32-bit integers one 64-bit integer example paddusb packed add unsigned saturated byte instruction adds two vectors containing eight 8-bit unsigned integers together elementwise addition would overflow saturates yielding 255 maximal unsigned value represented byte rather specialized instructions generally require special coding programmer used changes core include 6-stage pipeline vs. 5 p5 return stack first done cyrix 6x86 better parallelism improved instruction decoder 32 kb l1 cache 4-way associativity vs. 16 kb 2-way p5 4 write buffers could used either pipeline vs. one corresponding pipeline p5 improved branch predictor taken pentium pro 512-entry buffer vs. 256 p5 contained 4.5 million transistors area 140 mm fabricated 0.28 µm cmos process metal pitches previous 0.35 µm bicmos process intel described 0.35 µm similar transistor density process four levels interconnect p55c compatible common socket 7 motherboard configuration voltage requirements powering chip differ standard socket 7 specifications motherboards manufactured socket 7 prior establishment p55c standard compliant dual intensity required proper operation chip intel temporarily manufactured upgrade kit called overdrive designed correct lack planning motherboard makers part pentium mmx notebook cpus used mobile module held cpu module pcb cpu directly attached smaller form factor module snapped notebook motherboard typically heat spreader installed made contact module however 0.25 µm tillamook mobile pentium mmx named city oregon module also held 430tx chipset along system 512 kb sram cache memory introduction pentium competitors nexgen amd cyrix texas instruments announced pentium-compatible processors 1994 cio magazine identified nexgen nx586 first pentium-compatible cpu pc magazine described cyrix 6x86 first followed amd k5 delayed due design difficulties amd later bought nexgen order help design amd k6 cyrix purchased national semiconductor later processors amd intel retain compatibility original pentium manuals provide overview pentium processor features
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Computer architecture
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kernel panic kernel panic sometimes abbreviated kp safety measure taken operating system kernel upon detecting internal fatal error either unable safely recover system continue run without much higher risk major data loss term largely specific unix unix-like systems microsoft windows operating systems equivalent term stop error resulting bug check screen presents bug check code blue background early versions windows colloquially known blue screen death bsod green background xbox one platform well windows 10 builds kernel routines handle panics known codice_1 t-derived bsd unix source code generally designed output error message console dump image kernel memory disk post-mortem debugging either wait system manually rebooted initiate automatic reboot information provided highly technical nature aims assist system administrator software developer diagnosing problem kernel panics also caused errors originating outside kernel space example many unix operating systems panic init process runs userspace terminates unix kernel maintains internal consistency runtime correctness assertions fault detection mechanism basic assumption hardware software perform correctly failure assertion results panic i.e voluntary halt system activity kernel panic introduced early version unix demonstrated major difference design philosophies unix predecessor multics multics developer tom van vleck recalls discussion change unix developer dennis ritchie remarked dennis easily half code writing multics error recovery code said left stuff error routine called panic called machine crashes holler hall 'hey reboot original codice_1 function essentially unchanged fifth edition unix vax-based unix 32v output error message information dropped system endless idle loop source code codice_1 function v6 unix unix codebase enhanced codice_1 function also enhanced dump various forms debugging information console panic may occur result hardware failure software bug operating system many cases operating system capable continued operation error occurred however system unstable state rather risking security breaches data corruption operating system stops prevent damage facilitate diagnosis error usual cases restart recompiling kernel binary image source code kernel panic booting resulting kernel common problem kernel correctly configured compiled installed add-on hardware malfunctioning ram could also sources fatal kernel errors start due incompatibility os missing device driver kernel may also go codice_1 unable locate root file system final stages kernel userspace initialization panic typically triggered spawning init fails panic might also triggered init process terminates system would unusable following implementation linux kernel final initialization codice_6 ref name= lxr init/main.c linux/init/main.c lxr cross referencer /ref kernel panics appear linux like unix-like systems also generate another kind error condition known kernel oops case kernel normally continues run killing offending process oops could cause subsystems resources become unavailable later lead full kernel panic linux kernel kernel panic causes keyboard leds blink visual indication critical condition kernel panic occurs mac os x 10.2 10.7 computer displays multilingual message informing user need reboot system prior 10.2 traditional unix-style panic message displayed 10.8 later computer automatically reboots displays message restart format message varies version version sometimes five kernel panics within three minutes first one mac display prohibitory sign 30 seconds shut known recurring kernel panic versions 10.2 text superimposed standby symbol full screen debugging information saved nvram written log file reboot 10.7 feature automatically restart kernel panic cases 10.2 later white text detailing error may appear addition standby symbol
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Computer architecture
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