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swatting swatting criminal harassment tactic deceiving emergency service via means hoaxing emergency services dispatcher sending police emergency service response team another person address triggered false reporting serious law enforcement emergency bomb threat murder hostage situation alleged incident also triggered false report mental health emergency reporting person allegedly suicidal homicidal may may armed united states maximum prison sentence handed court march 2019 swatter 20 years jail fatal 2017 swatting violation term derives law enforcement unit swat special weapons tactics specialized type police unit many countries carrying military-style equipment door breaching weapons submachine guns automatic rifles sniper rifles threat may result evacuations schools businesses advocates called swatting described terrorism due use intimidate create risk injury death making false reports emergency services criminal offense many countries punishable fines imprisonment causes tax dollars wasted city county responding false report serious law enforcement emergency california swatters bear full cost response lead fines 10,000 bomb threats concern police 1970s public buildings airports evacuated response hoax calls designed cause mass panic public disruption delay exams educational institutions recent decades hoax callers sometimes make use techniques disguise identity country origin swatting origins prank calls emergency services years callers used increasingly sophisticated techniques direct response units particular types particular attempts swat teams dispatched particular locations spawned term swatting term used fbi early 2008 also entered oxford dictionaries online 2015 caller id spoofing social engineering tty prank calls phone phreaking techniques may variously combined swatting perpetrators 911 systems including computer telephony systems human operators tricked calls placed cities hundreds miles away location purported call even countries caller typically places 911 call using spoofed phone number hide fraudulent caller real location goal tricking emergency authorities responding swat team fabricated emergency swatting linked action doxing obtaining broadcasting often via internet address details individual intent harass endanger united states swatting prosecuted federal criminal statutes 2011 california state senator ted lieu authored bill increase penalties swatting family became victim swatting bill proposed dozen police officers along firefighters paramedics surrounded family home 2015 new jersey state assemblyman paul d. moriarty announced bill increase sentences hoax emergency calls targeted hoax bill proposed prison sentences ten years fines 150,000 2015 bipartisan bill congress sponsored katherine clark patrick meehan made swatting federal crime increased penalties congresswoman clark wrote op-ed hill saying 2.5 million cases cyber stalking 2010 2013 resulted 10 cases prosecuted although source provided revenge bill anonymous caller fraudulently called police rep. clark house january 31 2016 brazil swatting prosecuted criminal code following articles january 15 2015 sentinel oklahoma washita county dispatchers received 911 calls someone identified dallas horton told dispatchers placed bomb local preschool washita county sheriff deputies sentinel police chief louis ross made forced entry horton residence ross wearing bulletproof vest shot several times horton investigation revealed calls originate home led oklahoma state bureau investigation agents believe horton unaware law enforcement officers making entry james edward holly confessed investigators made calls two nonfunctioning phones angry horton ross shot multiple times chest arm injured treated injuries released local hospital december 28 2017 wichita police officer shot man named andrew finch kansas home swatting incident andrew finch later died hospital based series screenshotted twitter posts wichita eagle suggests finch unintended victim swatting two players team got heated argument 1.50 usd bet december 29 2017 lapd arrested 25-year-old serial-swatter tyler raj barriss known online swautistic xbox live goredtutor36 connection incident 2018 barriss indicted federal grand jury along two others involved incident according u.s. attorney stephen mcallister false hoax charge carries maximum punishment life federal prison charges carry sentences 20 years march 29 2019 barriss sentenced 20 years imprisonment 2009 blind phreaker matthew weigman caught help verizon fraud-investigator named billy smith weigman sentenced 11 years federal prison pleaded guilty charges including involvement swatting conspiracy attempting retaliate witness 2012 cnn interviewed political commentator erick erickson discuss incident victim swatting caller 911 gave erickson address claimed incident prompted florida 24th congressional district representative sandy adams push justice department investigation 2013 number u.s. celebrities became victims swatting including sean combs past swatting incidents homes ashton kutcher tom cruise chris brown miley cyrus iggy azalea jason derulo snoop dogg justin bieber clint eastwood 2013 network fraudsters involved carding doxing public officials using stolen credit reports targeted computer security expert brian krebs malicious police reports mir islam leader group also used swatting hoaxes prosecutor stephen p. heymann congressman mike rogers girl cyberstalking turned romantic proposals islam convicted doxing swatting 50 public figures including michelle obama robert mueller john brennan well krebs sentenced two years prison ukrainian computer hacker sergey vovnenko convicted trafficking stolen credit cards well planning purchase heroin ship brian krebs swatting sentenced 15 months prison italy 41 months prison new jersey may 2014 curtis gervais ottawa ontario arrested made thirty fraudulent emergency calls across north america leading sixty charges including uttering death threats conveying false information intent alarm public mischief mischief property gervais sentenced nine months home detention ontario court justice mitch hoffman noted hoax calls resulted evacuations schools homes shopping center caused thousands people lives put turmoil terrorized also called massive waste public resources significant cost emergency services therefore taxpayer august 27 2014 youtube user jordan mathewson known online kootra live streamed game twitch viewer called 911 claiming shooting building hostages swat team raided office mathewson gaming company creatures llc operating mathewson thrown ground searched officers searched room events broadcast live internet law enforcement blocked camera lens mathewson desk videos swatting went viral gaining four million views youtube reported news programs world september 11 2014 bukkit programmer wesley wolvereness wolfe victim swatting incident unidentified skype caller told police wolfe shot parents killing spree wolfe believed targeted retaliation issuing dmca takedown craftbukkit bukkit repository november 6 2014 home unnamed executive bungie developer halo destiny franchises raided local police call purported someone inside house said hostage situation residence caller demanded ransom 20,000 claimed planted explosives yard 45 minutes police determined call originated computer residence stated perpetrator hoax could face fine one year jail apprehended december 5 2014 police coquitlam british columbia arrested teenager using pseudonym 'obnoxious committed least 40 attempted successful acts swatting several countries teenager historically targeted mostly young female gamers ignored friend requests league legends twitter used social engineering techniques skype tracking tools obtain address details victims companies including cox communications voip calling mask real location went far live stream swatting calls youth pleaded guilty 23 crimes new york times article case criticized twitch failing block user associates site january 3 2015 twenty portland oregon police officers sent former home grace lynn transgender woman stated culmination months online harassment gamergate supporters withdrew support movement swatter coming serbia claimed affiliated gamergate lynn said alerted incident proactively checked online harassment daily defused situation contacting police may 2015 zachary lee morgenstern 19 cypress texas arrested made number hoax bomb threats swatting calls minnesota ohio massachusetts including two schools marshall minnesota police obtained ip address twitter google morgenstern pleaded guilty several federal crimes december 2015 sentenced 41 months prison august 2015 founder website mumsnet target swatting resulted deployment london metropolitan police service armed response unit attending home address hoax concurrent denial-of-service attack mumsnet website threats swatting attack january 31 2016 around 10pm u.s. representative katherine clark swatted anonymous caller claimed active shooter home melrose police responded home left determining call hoax rep. clark sponsored bill called 'interstate swatting hoax act 2015 aimed increasing penalties swatting well making swatting federal crime incident said sympathetic people victims swatting sunday night fully understands like stated swatting really cause double april 28 2017 twitch user paul denino pseudonym ice poseidon live streaming boarding american airlines flight plane landed law enforcement showed airport apron removed denino one person plane anonymous caller claimed denino bomb october 16 2017 bitcoin engineer jameson lopp neighborhood locked law enforcement responding reported hostage situation anonymous caller claimed shot killed one person holding others hostage ransom house rigged c4 lopp later wrote first person account ordeal offered bounty information leading arrest conviction perpetrator may 16 2018 popular streamer former professional overwatch player felix xqc lengyel home raided police handcuffed mid-stream california apartment lengyel later revealed three guns pointed overwatch league analyst brennon hook stated raid due noise complaint neighbor lengyel asserted act swatting june 5 2018 police called parkland florida home stoneman douglas high school shooting survivor gun-control activist david hogg caller claimed hostage situation prompting emergency response included swat team hogg home time washington d.c. family receive robert f. kennedy human rights award one organizers march lives winning 3 million top prize fortnite world cup july 2019 16-year-old kyle bugha giersdorf swatted august 2019 stream local swat team armed arrival however situation diffused one officers recognized giersdorf championship recognized call prank october 2018 seattle police department spd launched opt-in registry aimed people fear might become victims swatting celebrities live streamers using registry people provide cautionary information spd inform officers responding potential swatting attempts targeted victim address security reporter brian krebs recommends police departments take extra care responding calls received non-emergency numbers text-to-speech services tty since methods often employed out-of-area swatters connect regional 911 center
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Computer security
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leanix leanix name stands lean information exchange software vendor provides tools services areas enterprise architecture application portfolio management small medium large enterprises company headquarters bonn subsidiary us office boston leanix mentioned gartner magic quadrant enterprise architecture tools 2015 leanix founded jörg beyer andré christ 2012 prior founding leanix jörg beyer andré christ worked various management positions i.e cio deutsche post first 3 years company bootstrapped grew without external funding thanks first product leanix first released october 2012 february 2015 capnamic ventures iris capital invested usd 2.5 mio eur 2.2 mio series financing round 2018 jörg g. beyer retired managing director andré christ stays sole ceo leanix raised 30 million december 2018 round led insight venture partners since founding company focusses exclusively providing software product leanix used customers web-based information platform store information applications architecture company company reports leanix employed media insurance logistics energy manufacturing e-commerce enterprises anywhere 100 100,000 employees customers include axel springer se haworth inc. helvetia insurance kühne nagel ruag rwe zalando one major use case market leading publishing company germany axel springer describes usage leanix part digital transformation organization building bi-modal architecture support traditional fast another use case zalando uses leanix central platform enterprise architecture environment information many microservices gathered automatically injected leanix platform using open rest api product available software service cloud september 2015 company received data privacy certificate leanix global network partners order provide specialised support areas integrations consulting company partnership program place train partners give access knowledge resources certified partners include example enzyme consulting based spain berlin based company signavio among one first out-of-the box integrations product business process management besides integrations tools like jira confluence leanix partnership onelogin single-sign via saml customers build integrations using open source sdks java php python c leanix mentioned gartner magic quadrant enterprise architecture tools 2015 out-of-the-box affordable cloud-based ea tool especially suitable midsize smaller organizations companies different industries written testimonials leanix gartner peer insights mentioning leanix great portfolio management tool apm features 2015 leanix awarded 2nd place innovation award digital transformation
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Distributed computing architecture
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vulnerability management vulnerability management cyclical practice identifying classifying prioritizing remediating mitigating software vulnerabilities vulnerability management integral computer security network security must confused vulnerability assessment vulnerabilities discovered vulnerability scanner analyzes computer system search known vulnerabilities open ports insecure software configurations susceptibility malware infections may also identified consulting public sources nvd subscribing commercial vulnerability alerting service symantec deepsight vulnerability datafeed accenture vulnerability intelligence service unknown vulnerabilities zero-day may found fuzz testing identify certain kinds vulnerabilities buffer overflow relevant test cases analysis facilitated test automation addition antivirus software capable heuristic analysis may discover undocumented malware finds software behaving suspiciously attempting overwrite system file correcting vulnerabilities may variously involve installation patch change network security policy reconfiguration software educating users social engineering
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Computer security
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moralityware moralityware subset malware infects pc intention imposing morality upon user example blocking pornographic websites first cited example appeared eweek example cited trojan deemed yusufali-a sophos said monitor internet explorer title bars content potentially relating pornography upon triggering internet explorer window minimized window take place quote koran translated several languages time trojan display exit button trap mouse cursor within window button attempted clicked displaying message oh 'm cage trojan require computer logged minimum return control mouse remains unclear whether trojan designed joke truly moral guardian regardless anti-virus makers blocking software virus definitions additionally remains seen whether indicates trend malware simply new term one-time occurrence
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Computer security
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poor man copyright poor man copyright method using registered dating postal service notary public highly trusted source date intellectual property thereby helping establish material one possession since particular time concept based notion event intellectual property misused third party poor-man copyright would least establish legally recognized date possession proof third party may possess countries central copyright registration authority difficult author prove work created united kingdom patent office says ... copy could deposited bank solicitor alternatively creator could send copy special delivery post gives clear date stamp envelope leaving envelope unopened return number private companies operate unofficial registers would sensible check carefully paying choosing route important note prove work original created ... provision us copyright law regarding type protection poor man copyright therefore substitute registration according section 101 u.s copyright act 1976 17 u.s.c 408 registration work copyright office prerequisite copyright protection furthermore eric goldman noted absence cases actually giving value poor man copyright
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Computer security
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la abadía del crimen la abadía del crimen abbey crime computer video game programmed 1987 paco menéndez graphics made juan delcán game originally conceived version umberto eco book name rose however paco menéndez opera soft received reply eco order secure rights name game released la abadía del crimen abbey crime fact original working title novel name rose game videoadventure 3d isometric graphics franciscan friar william occam william baskerville book young novice adso discover perpetrator series murders medieval italian abbey player controls movement friar fra william mistakenly described monk user manual player also possibility control movement novice adso within screen fra william key controlling novice pressed follows fra william time game features characters representing monks abbey behave according programmed artificial intelligence move throughout mapping abbey show series dialogs shown written text moved along lower part screen extensive mapping abbey represented large series screens 3d isometric graphics series objects collected order successfully complete game action occurs seven days subdivided different canonical hours time day current hour indicated bottom left screen game starts abbot welcoming fra william explaining monk disappeared also explains fra william obligated obey orders abbot rules monastery attend religious services meals stay cell night research crimes pursued game novice adso remind players attend offices meals players follow forget way church refectory players disobey orders late services etc. obsequium level indicated bottom right-hand-side screen drop obsequium latin subservience obedience obsequium level drops zero abbot tolerate disrespect longer players leave abbey would result game actions missing prayer office altogether caught wandering around night result immediate expulsion end game game originally developed amstrad cpc 6128 8 bit platform ported systems zx spectrum msx pc amstrad cpc 464 version different 6128 original since several rooms decoration removed fit game 64k 464 spectrum version 128 platform music played game corresponds minuet g major sonata flute bwv 1033 bach crystal palace gwendal original pc version also featured ave maria schubert short chorus recording played speaker player went church form copy protection pc version illegal copy game created church area instead ave maria voice crying pirata pirata pirata several times heard instead game crash game programmed making capacities 8-bit computers taking high level care details plot mapping graphics artificial intelligence characters sound etc made game regarded one best video games made 8-bit computers spite singular qualities expressed positive initial reviews game modest commercial success never officially released outside spain country came achieve cult following game also considered one perfect ten games spectrum 128 according retro gamer
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Computer architecture
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beamrider beamrider fixed shooter designed intellivision david rolfe published activision 1983 game ported atari 2600 slightly reduced feature set atari 5200 atari 8-bit family colecovision commodore 64 zx spectrum msx platforms beamrider takes place earth atmosphere large alien shield called restrictor shield surrounds earth player objective clear shield 99 sectors alien craft piloting beamrider ship beamrider equipped short-range laser lariat limited supply torpedoes player given three start sector clear sector fifteen enemy ships must destroyed sentinel ship appear destroyed using torpedo remain bonus points enemy ships destroyed torpedoes must simply dodged occasionally sector yellow rejuvenators extra lives appear picked extra ship shot transform ship-damaging debris activision offered special beamrider patches players could get sector 14 40,000 points sent screenshot accomplishment deseret news 1984 gave colecovision version beamrider three stars describing basically slide-and-shoot space game reviewer commodore described commodore 64 version game really good wholesome arcade zapping game
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Computer architecture
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aladdin knowledge systems aladdin knowledge systems formerly company produced software digital rights management internet security company acquired safenet inc 2009 corporate headquarters located belcamp md aladdin knowledge systems founded 1985 jacob yanki margalit 23 years old soon joined brother dany margalit took responsibility product development age 18 time completing mathematics computer science degree tel aviv university early years company developed two product lines artificial intelligence package dropped early hardware product prevent unauthorized software copying similar digital rights management yanki raised 10,000 initial capital company digital rights management product became success 1993 generated sales 4,000,000 year company initial public offering nasdaq raising 7,900,000 2004 company shares also listed tel aviv stock exchange 2007 company annual revenues reached 105 million mid-2008 vector capital attempting purchase aladdin vector initially offered 14.50 per share aladdin founder margalit refused offer arguing company worth aladdin shareholders agreed merger february 2009 11.50 per share cash march 2009 vector capital acquired aladdin officially merged safenet aladdin hasp product line digital rights management drm suite protection licensing software 40 global market share used 30,000 software publishers used across many platforms windows linux mac hasp stands hardware software piracy company first product evolved complete digital rights management suite includes software option back office management application recent years also software service capability late 1990s company started diversifying began offering internet security network security products offering two product lines etoken portable device two-factor authentication pasdigital identity management mainly deployed usb token esafe line integrated network security content filtering products protecting networks cracked pirated internet-borne software used adobe macromedia 30-days product trials
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Computer security
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cloud28+ cloud28+ worldwide cloud computing services marketplace federation cloud computing organizations developed sponsored hewlett packard enterprise hpe december 2016 world biggest aggregator cloud computing services federation originally launched europe march 2015 aim accelerating cloud adoption europe opened members worldwide november 2016 point around 330 member companies offered around 1,300 infrastructure-as-a-service iaas platform-as-a-service paas software-as-a-service saas services cloud28+ launched hpe event frankfurt germany march 2015 development since april 2014 purpose creating single catalogue european cloud computing services hp trying figure grow ecosystem cloud suppliers europe mapping services providers isvs resellers according hp executive xavier poisson gouyou beauchamps 6 june 2017 poisson cloud leadership award 2017 datacloud europe judges citing growth cloud28+ making selection microsoft joined cloud28+ technology partner july 2017 pledging collaborate hpe create new on-boarding programme designed bring independent software vendors isvs marketplace february 2018 mphasis partnered hpe cloud28+ specific solutions services launch cloud28+ required services catalog built hpe helion version openstack open-source cloud software platform may 2016 support extended include microsoft azure vmware docker technologies service hub also extended app center automates installation docker-based applications
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Distributed computing architecture
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university toolkit university toolkit software package developed mpaa university system administrators track log types much traffic goes network internet provided university toolkit available free online developer ubuntu operating system toolkit based contacted mpaa requested taken citing gpl violations stating gpl software must source code released gpl well mpaa released source code university toolkit despite supposedly based entirely open-source software specifically snort ntop
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Computer security
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large-file support large-file support lfs term frequently applied ability create files larger either 2 4 gib 32-bit filesystems traditionally many operating systems underlying file system implementations used 32-bit integers represent file sizes positions consequently file could larger 2 − 1 bytes 4 gib − 1 many implementations problem exacerbated treating sizes signed numbers lowered limit 2 − 1 bytes 2 gib − 1 files large 32-bit operating systems handle came known large files limit quite acceptable time hard disks smaller general increase storage capacity combined increased server desktop file usage especially database multimedia files led intense pressure os vendors remove limitation 1996 multiple vendors responded forming industry initiative known large file summit obvious backronym lfs summit tasked define standardized way switch 64-bit numbers represent file sizes merely ensuring sizes treated unsigned numbers would increase limit 2 gib−1 4 gib−1 would stopgap measure given explosive growth data storage nevertheless windows 95b dos 7.10 introduced api extension notably extended file open call access files full 4 gib−1 bytes possible fat16b fat32 volumes applications aware extension continue use traditional file open call thereby still limited maximum 2 gib−1 bytes backward compatibility switch caused deployment issues required design modifications consequences still seen
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Computer file systems
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commodore dos commodore dos also known cbm dos disk operating system used commodore 8-bit computers unlike doses loaded disk computer ram executed cbm dos executed internally drive dos resides rom chips inside drive run one dedicated mos 6502 family cpus thus data transfer commodore 8-bit computers disk drives closely resembles local area network connection typical disk/host transfers least seven distinctly numbered versions commodore dos known exist following list gives version numbers related disk drives unless otherwise noted drives 5¼-inch format lp code designates low profile drives drives whose model number starts 15 connect via commodore unique cbm-488 serial talk/listen protocols others use parallel ieee-488 version 2.6 far commonly used known dos version due use 1541 part c64 systems revised firmware 1571 fixed relative file bug also identified v3.0 thus possible tell two versions apart version number alone 1541 commodore floppy disk contain 144 files flat namespace subdirectories directory stored reserved track 18 located halfway hub edge 35-track single-sided disk file name may 16 bytes length theoretically unique using direct access methods directory structure possible rename file another—although accessing files may difficult impossible files identical names usually serve purpose except inform visually manage files one popular trick used example final cartridge iii add files named codice_1 type codice_2 directory files could rearranged around lines form groups many game developers warez group members demoscene hackers used clever custom directory entries well file names may contain shifted space character codice_3 directory listing viewed basic portion file name beyond codice_3 character appear separated first part file name quotation mark causing basic consider part full file name feature used create directory entries appear directory listing example user moves cursor beginning line types word codice_5 file size presses basic interprets causing program loaded memory anything colon secondary address executed since computer ignores command load alternatively user could press program automatically null byte embedded file name interrupt listing loading basic three null bytes makes difficult list basic many machine language programmers would experiment null bytes attempt make harder basic programmers access code tamper basic directory accessed non-executable pseudo-basic program case dual drive followed codice_6 first line line number 0 1 indicating drive number showing reverse video name id disk shorthand code dos version created codes vary far dos versions use incompatible disk formats 2a used 5.25-inch dos versions 3d the-3.5 inch 1581 lines size file disk blocks pseudo line number followed file name quotes three-letter type code last line shows number unallocated blocks disk pseudo line number followed words blocks free commodore 64 entering flood screen garbage instead loading directory basic ram drive assigns directory load address 0401 1025 equivalent start basic commodore pet corresponds default screen memory c64 starting second character first line screen viewing directory command overwrites basic program memory dos wedge various third-party cartridges extenders epyx fastload action replay final cartridge iii allow viewing disk directory using special commands load directory screen memory without destroying current basic program versions commodore basic include codice_7 codice_8 command performs function following file types supported presence asterisk codice_19 prepended file type directory listing example codice_20 indicates file properly closed writing drive commanded close file opened writing associated buffer flushed disk block availability map bam updated accurately reflect blocks used program crash problem user removing disk file open results orphan file also referred poison splat file buffers flushed bam accurately reflect disk usage putting disk risk corruption poison file generally accessed opened modify mode attempt use dos codice_21 command delete file may cause filesystem corruption crosslinking practical method removing one files opening file modify mode fixing validating disk see dos codice_22 command latter rebuilds bam removes poison file references directory infamous save-with-replace bug could result creation splat files codice_23 special type written on-disk directory entry files deleted files shown normal directory listing data blocks directory entries reused files subsequently created utility programs allow un-deletion files data blocks directory entries yet overwritten files codice_24 commonly used insert banners comment sections directory listing file types codice_25 example codice_26 locked deleted—they opened reading however commodore dos command explicitly set clear status many third-party utilities written allow done utilities generally read directory using direct-access commands perform necessary modifications raw data write changes back disk accessing files primarily issue host computer kernal rom computer contains necessary primitive routines needed access files basic rom contains higher level abstraction file access using basic syntax components concern dos file name parsing secondary address section give overview necessary basic commands sake completeness opening file commodore disk unit entails processing number parameters vaguely analogous file opening procedures environments since dos actually running drive controller file opening sequence must pass enough information drive assure unambiguous interpretation typical statement basic write sequential file would follows parameters following codice_27 verb follows files also loaded saved codice_5 codice_34 commands file name specifiers also used example saves basic program codice_12 program file saves basic program sequential file secondary address n't specified specified 0 e.g file saved/loaded basic memory area c64 starts default 0801 secondary address specified non-zero value e.g program loaded starting address specified file prg header first two bytes file —this form command common loading machine code programs load relocation first introduced vic-20 machine could start basic ram several different locations depending memory expansion installed older commodore pet series support relocation would effect file would loaded memory region saved load relocation happens host exception said secondary address used device-internally since pet relocate files basic programs written later commodore machines must modified using sector editor change header bytes also possible use pet built-in machine language monitor change link address basic program loading command load first program disk starting file-specified memory location one popular load commands platforms method start majority commercial software example note fact wildcard expansion pick first catalog name file disk accessed name last-used file kept memory subsequent commands load file rather first however always load first file disk directories disks two-drive units accessed codice_36 codice_37 access directory actual files one drive happen named codice_38 partial directories loaded adding colon template example would load partial directory shows files whose name starts letter k type prg partial directories still contain initial disk name line final blocks free line commodore dos also offers save-with-replace command allows file saved existing file without need first codice_39 existing file done prepending codice_40 symbol file name codice_27 codice_34 operation instance years rumors spread beginning 4040 drive bug command implementation first denied commentators prizes offered prove existence bug early 1985 compute magazine advised readers avoid using command year various authors independently published articles proving save-with-replace bug real including methods could triggered affected devices included single-drive 1541 dual-drive 4040 8050 8250 exhibit issue commentators suggested bug could avoided always explicitly specifying codice_29 drive number saving though later shown disk operations without drive number sufficient lead bug bug stemmed fact affected dos implementations modified versions dos contained earlier commodore pet dual drives 8050 created phantom drive codice_44 single-drive systems resulting allocation unnecessary buffer conditions since save-with-replace command used five drive buffers method phantom buffer allocated meet specifications resulted scrambled data written disk conditions september 1986 philip a. slaymaker published article describing great detail cause bug providing patches 1541 drive roms readers eprom burner could produce patched roms could swapped drive commodore made aware slaymaker findings never issued official update original 1541 roms fix bug revision 5 1571 roms also roms 1541-c 1541-ii drives although supported commodore known 1541-ii firmware 1541-c also used original 1541 drive using eproms fix bug drive well previously noted commodore dos accessed via command channel using syntax like used access files issuing commands dos retrieving status error messages generated response commands accomplished opening file device using 15 secondary address example retrieve display device status one could code example codice_45 hold error number zero error exists codice_46 terse text description error codice_47 represent disk track error occurred codice_31 sector track codice_47 error refers error exists equivalent returned four variables note codice_50 run mode verb also programs issue many disk commands customary open file device command channel start program close program finished commodore basic versions 4.0 later provide pseudo-variable referred codice_51 may used retrieve drive status lieu code reserved variable available earlier versions basic command channel must manually read demonstrated note immediately power-on reset dos revision returned example 1541 return error code 73 common drive models may used determine drive reset power-on state also command seeking relative type files codice_52 several block-level direct-access commands codice_53 codice_54 codice_55 block management codice_56 codice_57 drive memory manipulation execution program code drive processor codice_58 codice_59 codice_60 codice_61 user-definable functions codice_62 codice_63 commands theoretically user-definable functions rededicated accessing new functionality dos versions 1.0
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Operating systems
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navidad virus w32.navidad mass-mailing worm program virus discovered december 2000 designed spread email clients microsoft outlook masquerading electronic christmas card infected computers identified blue eye icons appear windows system tray users move mouse cursor eye icons presented variety different messages including one states emmanuel-god us may god bless u.and ash lk lj
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Computer security
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golden basket golden basket 1990 computer basketball game developed published opera soft opera sports label zx spectrum amstrad cpc msx ms-dos game features five-a-side basketball match showing lateral view
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Computer architecture
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socket am3+ am3+ modification am3 socket released mid-2011 designed cpus use amd bulldozer microarchitecture retains compatibility am3 processors vishera line amd cpus also use socket am3+ am3+ socket specification contains noteworthy design changes am3 predecessor 942 pin count am3+ increase one compared am3 socket layout am3+ socket larger pin socket diameter 0.51 mm compared 0.45 mm am3 socket faster serial link 3400 khz cpu power controller compared 400 khz am3+ socket offers improved power regulation power quality specifications including increased maximum current support 145 versus 110 also redesigned cpu cooler retention harness allowing slightly better airflow cpu cooling retaining cooler backward compatibility manufacturers brought am3+ support am3 motherboards via simple bios upgrade mechanical compatibility confirmed possible am3+ cpus fit am3 boards provided supply enough peak current another issue use sideband temperature sensor interface reading temperature cpu therefore cpu pwm fan headers may run full speed also certain power-saving features may work due lack support rapid vcore switching am3+ cpus technically pin-compatible am2 am2+ boards work due lack ddr2 controller cpu 4 holes fastening heatsink motherboard placed rectangle lateral lengths 48 mm 96 mm amd sockets socket am2 socket am2+ socket am3 socket am3+ socket fm2 cooling solutions therefore interchangeable
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Computer architecture
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voicexml voicexml vxml digital document standard specifying interactive media voice dialogs humans computers used developing audio voice response applications banking systems automated customer service portals voicexml applications developed deployed manner analogous web browser interprets visually renders hypertext markup language html receives web server voicexml documents interpreted voice browser common deployment architectures users interact voice browsers via public switched telephone network pstn voicexml document format based extensible markup language xml standard developed world wide web consortium w3c voicexml applications commonly used many industries segments commerce applications include order inquiry package tracking driving directions emergency notification wake-up flight tracking voice access email customer relationship management prescription refilling audio news magazines voice dialing real-estate information national directory assistance applications voicexml tags instruct voice browser provide speech synthesis automatic speech recognition dialog management audio playback following example voicexml document interpreted voicexml interpreter output hello world synthesized speech typically http used transport protocol fetching voicexml pages applications may use static voicexml pages others rely dynamic voicexml page generation using application server like tomcat weblogic iis websphere historically voicexml platform vendors implemented standard different ways added proprietary features voicexml 2.0 standard adopted w3c recommendation 16 march 2004 clarified areas difference voicexml forum industry group promoting use standard provides conformance testing process certifies vendors implementations conformant corporation ibm lucent motorola formed voicexml forum march 1999 order develop standard markup language specifying voice dialogs september 1999 forum released voicexml 0.9 member comment march 2000 published voicexml 1.0 soon afterwards forum turned control standard w3c w3c produced several intermediate versions voicexml 2.0 reached final recommendation stage march 2004 voicexml 2.1 added relatively small set additional features voicexml 2.0 based feedback implementations 2.0 standard backward compatible voicexml 2.0 reached w3c recommendation status june 2007 voicexml 3.0 next major release voicexml new major features includes new xml statechart description language called scxml w3c speech interface framework also defines standards closely associated voicexml speech recognition grammar specification srgs used tell speech recognizer sentence patterns expect hear patterns called grammars speech recognizer determines likely sentence heard needs extract semantic meaning sentence return voicexml interpreter semantic interpretation specified via semantic interpretation speech recognition sisr standard sisr used inside srgs specify semantic results associated grammars i.e. set ecmascript assignments create semantic structure returned speech recognizer speech synthesis markup language ssml used decorate textual prompts information best render synthetic speech example speech synthesizer voice use speak louder softer pronunciation lexicon specification pls used define words pronounced generated pronunciation information meant used speech recognizers speech synthesizers voice browsing applications call control extensible markup language ccxml complementary w3c standard ccxml interpreter used voicexml platforms handle initial call setup caller voice browser provide telephony services like call transfer disconnect voice browser ccxml also used non-voicexml contexts media server applications often necessary several call legs interact example multi-party conference deficiencies identified voicexml application companies designed specific scripting languages deal environment media server markup language msml convedia solution media server control markup language mscml snowshore solution snowshore owned dialogic convedia owned radisys languages also contain 'hooks external scripts like voicexml run call legs ivr functionality required ietf working group called mediactrl media control working successor scripting systems hoped progress open widely adopted standard
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Internet protocols
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simon peyton jones simon peyton jones born 18 january 1958 british computer scientist researches implementation applications functional programming languages particularly lazy functional programming peyton jones graduated trinity college cambridge 1980 went complete cambridge diploma computer science peyton jones worked industry two years serving lecturer university college london 1990 1998 professor university glasgow since 1998 worked researcher microsoft research cambridge england major contributor design haskell programming language lead developer glasgow haskell compiler ghc also co-creator programming language designed intermediate program representation language-specific front-end compiler general-purpose back-end code generator optimiser c -- used ghc also major contributor 1999 book cybernauts awake explored ethical spiritual implications internet peyton jones chairs computing school cas group organisation aims promote teaching computer science school following efforts 2019 appointed chair newly founded uk national centre computing education 2004 inducted fellow association computing machinery contributions functional programming languages 2011 received membership academia europaea 2011 simon marlow awarded sigplan programming languages software award work ghc received honorary doctorate university glasgow 2013 honorary doctorate university kent 2017 elected fellow royal society frs 2016 distinguished fellow british computer society dfbcs 2017
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Programming language topics
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high-level programming language high-level programming language vhll programming language high level abstraction used primarily professional programmer productivity tool high-level programming languages usually domain-specific languages limited specific application purpose type task often scripting languages especially extension languages controlling specific environment reason high-level programming languages often referred goal-oriented programming languages term vhll used 1990s today often called high-level programming languages used scripting perl python ruby visual basic
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Programming language topics
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windows management instrumentation windows management instrumentation wmi consists set extensions windows driver model provides operating system interface instrumented components provide information notification wmi microsoft implementation web-based enterprise management wbem common information model cim standards distributed management task force dmtf wmi allows scripting languages vbscript windows powershell manage microsoft windows personal computers servers locally remotely wmi comes preinstalled windows 2000 newer microsoft oses available download windows nt windows 95 windows 98 microsoft also provides command-line interface wmi called windows management instrumentation command-line wmic purpose wmi define proprietary set environment-independent specifications allow management information shared management applications wmi prescribes enterprise management standards related technologies windows work existing management standards desktop management interface dmi snmp wmi complements standards providing uniform model model represents managed environment management data source accessed common way wmi abstracts manageable entities cim collection providers development provider implies several steps major steps summarized follows since release first wmi implementation windows nt 4.0 sp4 era out-of-band download microsoft consistently added wmi providers windows many customers interpreted growth numbers providers sign wmi become microsoft ubiquitous management layer windows even microsoft never made commitment explicit constant increasing exposure management data wmi windows people systems management field started develop scripts automation procedures based wmi beyond scripting needs leading management-software packages mom sccm ads hp openview windows hpov bmc software ca inc. wmi-enabled capable consuming providing wmi information various user interfaces enables administrators operators capable scripting programming top wmi enjoy benefits wmi without even learning however want wmi scriptable gives opportunity consume wmi information scripts wmi-aware enterprise-management software someone willing develop one many wmi providers wmi offers many features box important advantages wmi tools also useful design development phases tools .net framework managementclass class represents common information model cim management class wmi class win32_logicaldisk case disk drive win32_process running program like notepad.exe example shows msndis_80211_servicesetidentifier wmi class used find ssid wi-fi network system currently connected language c msndis_80211_servicesetidentifier wmi class supported windows xp windows server 2003 wmi extensions wdm provide kernel-level instrumentation publishing information configuring device settings supplying event notification device drivers allowing administrators set data security wmi provider known wdm provider extensions part wdm architecture however broad utility used types drivers well scsi ndis wmi driver extensions service monitors drivers event trace providers configured publish wmi event trace information instrumented hardware data provided way drivers instrumented wmi extensions wdm wmi extensions wdm provide set windows device driver interfaces instrumenting data within driver models native windows oems ihvs easily extend instrumented data set add value hardware/software solution wmi driver extensions however supported windows vista later operating systems
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Operating systems
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denyhosts denyhosts log-based intrusion-prevention security tool ssh servers written python intended prevent brute-force attacks ssh servers monitoring invalid login attempts authentication log blocking originating ip addresses denyhosts developed phil schwartz also developer kodos python regular expression debugger denyhosts checks end authentication log recent failed login attempts records information originating ip addresses compares number invalid attempts user-specified threshold many invalid attempts assumes dictionary attack occurring prevents ip address making attempts adding codice_1 server denyhosts 2.0 support centralized synchronization repeat offenders blocked many computers site denyhosts.net gathers statistics computers running software denyhosts restricted connections using ipv4 work ipv6 denyhosts may run manually daemon cron job july 2007 register reported may july year compromised computers oracle uk listed among ten worst offenders launching brute force ssh attacks internet according public denyhosts listings investigation oracle able refute suggestions computers compromised daniel b. cid wrote paper showing denyhosts well similar programs fail2ban blockhosts vulnerable remote log injection attack technique similar sql injection specially crafted user name used trigger block site chosen attacker fixed version 2.6 since development original author phil schwartz release version 2.6 december 2006 claimed version 2.7 november 2008 actual downloadable package available development first continued february 2012 matt ruffalo github repository independent separate fork started almost-identically named denyhost sourceforge project site release different version 2.7 may 2014 version 2.9 new sourceforge project merged earlier github repository newer versions available via means software runs centralized synchronization server denyhosts versions 2.0 use never released independent synchronization server software developed jan-pascal van best since june 2015 general references
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Computer security
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arm cortex-m arm cortex-m group 32-bit risc arm processor cores licensed arm holdings intended microcontroller use shipped tens billions devices cores consist cortex-m0 cortex-m0+ cortex-m1 cortex-m3 cortex-m4 cortex-m7 cortex-m23 cortex-m33 cortex-m35p cortex-m4 m7 m33 m35p cores fpu silicon option included silicon cores known cortex-mx fpu cortex-mxf x core number arm cortex-m family arm microprocessor cores designed use microcontrollers asics assps fpgas socs cortex-m cores commonly used dedicated microcontroller chips also hidden inside soc chips power management controllers i/o controllers system controllers touch screen controllers smart battery controllers sensors controllers though 8-bit microcontrollers popular past cortex-m slowly chipping away 8-bit market prices low-end cortex-m chips moved downward cortex-m become popular replacements 8-bit chips applications benefit 32-bit math operations replacing older legacy arm cores arm7 arm9 arm holdings neither manufactures sells cpu devices based designs rather licenses processor architecture interested parties arm offers variety licensing terms varying cost deliverables licensees arm provides integratable hardware description arm core well complete software development toolset right sell manufactured silicon containing arm cpu integrated device manufacturers idm receive arm processor ip synthesizable rtl written verilog form ability perform architectural level optimizations extensions allows manufacturer achieve custom design goals higher clock speed low power consumption instruction set extensions including floating point optimizations size debug support etc determine components included particular arm cpu chip consult manufacturer datasheet related documentation silicon options cortex-m cores additional silicon options cortex-m0 m0+ m1 implement armv6-m architecture cortex-m3 implements armv7-m architecture cortex-m4 cortex-m7 implements armv7e-m architecture architectures binary instruction upward compatible armv6-m armv7-m armv7e-m. binary instructions available cortex-m0 cortex-m0+ cortex-m1 execute without modification cortex-m3 cortex-m4 cortex-m7 binary instructions available cortex-m3 execute without modification cortex-m4 cortex-m7 cortex-m33 cortex-m35p thumb-1 thumb-2 instruction sets supported cortex-m architectures legacy 32-bit arm instruction set n't supported six cortex-m cores implement common subset instructions consists thumb-1 thumb-2 including 32-bit result multiply cortex-m0 cortex-m0+ cortex-m1 cortex-m23 designed create smallest silicon die thus fewest instructions cortex-m family cortex-m0 m0+ m1 include thumb-1 instructions except new instructions cbz cbnz added armv7-m architecture cortex-m0 m0+ m1 include minor subset thumb-2 instructions bl dmb dsb isb mrs msr cortex-m3 m4 m7 m33 m35p base thumb-1 thumb-2 instructions cortex-m3 adds three thumb-1 instructions thumb-2 instructions hardware integer divide saturation arithmetic instructions cortex-m4 adds dsp instructions optional single-precision floating-point unit vfpv4-sp cortex-m7 adds optional double-precision fpu vfpv5 cortex-m23 m33 add trustzone instructions arm architecture arm cortex-m series removed features older legacy cores capabilities 32-bit arm instruction set duplicated many ways thumb-1 thumb-2 instruction sets arm features n't similar feature 16-bit thumb-1 instruction set evolved time since first released legacy arm7t cores armv4t architecture new thumb-1 instructions added legacy armv5 armv6 armv6t2 architectures released 16-bit thumb-1 instructions removed cortex-m cores cortex-m0 core optimized small silicon die size use lowest price chips key features cortex-m0 core silicon options following microcontrollers based cortex-m0 core following chips cortex-m0 secondary core cortex-m0+ optimized superset cortex-m0 cortex-m0+ complete instruction set compatibility cortex-m0 thus allowing use compiler debug tools cortex-m0+ pipeline reduced 3 2 stages lowers power usage addition debug features existing cortex-m0 silicon option added cortex-m0+ called micro trace buffer mtb provides simple instruction trace buffer cortex-m0+ also received cortex-m3 cortex-m4 features added silicon options memory protection unit mpu vector table relocation key features cortex-m0+ core silicon options following microcontrollers based cortex-m0+ core following chips cortex-m0+ secondary core smallest arm microcontrollers cortex-m0+ type 2014 smallest 1.6 mm 2 mm kinetis kl03 21 june 2018 world smallest computer computer device announced based arm cortex-m0+ including ram wireless transmitters receivers based photovoltaics university michigan researchers 2018 symposia vlsi technology circuits paper 0.04mm3 16nw wireless batteryless sensor system integrated cortex-m0+ processor optical communication cellular temperature measurement device 1/10th size ibm previously claimed world-record-sized computer months back march 2018 smaller grain salt cortex-m1 optimized core especially designed loaded fpga chips key features cortex-m1 core silicon options following vendors support cortex-m1 soft-cores fpga chips key features cortex-m3 core silicon options following microcontrollers based cortex-m3 core following chips cortex-m3 secondary core following fpgas include cortex-m3 core following vendors support cortex-m3 soft-cores fpga chips conceptually cortex-m4 cortex-m3 plus dsp instructions optional floating-point unit fpu core fpu known cortex-m4f key features cortex-m4 core silicon options following microcontrollers based cortex-m4 core following microcontrollers based cortex-m4f m4 fpu core following chips either cortex-m4 m4f secondary core cortex-m7 high-performance core almost double power efficiency older cortex-m4 features 6-stage superscalar pipeline branch prediction optional floating-point unit capable single-precision optionally double-precision operations instruction data buses enlarged 64-bit wide previous 32-bit buses core contains fpu known cortex-m7f otherwise cortex-m7 key features cortex-m7 core silicon options following microcontrollers based cortex-m7 core cortex-m23 core announced october 2016 based newer armv8-m architecture previously announced november 2015 conceptually cortex-m23 similar cortex-m0+ plus integer divide instructions trustzone security features also 2-stage instruction pipeline key features cortex-m23 core silicon options following microcontrollers based cortex-m23 core cortex-m33 core announced october 2016 based newer armv8-m architecture previously announced november 2015 conceptually cortex-m33 similar cross cortex-m4 cortex-m23 also 3-stage instruction pipeline key features cortex-m33 core silicon options following microcontrollers based cortex-m33 core cortex-m35p core announced may 2018 conceptually cortex-m33 core new instruction cache plus new tamper-resistant hardware concepts borrowed arm securcore family configurable parity ecc features limited public information currently available cortex-m35p technical reference manual released 2019 following microcontrollers based cortex-m35p core documentation arm chips extensive past 8-bit microcontroller documentation would typically fit single document microcontrollers evolved everything required support documentation package arm chips typically consists collection documents ic manufacturer well cpu core vendor arm holdings typical top-down documentation tree ic manufacturers additional documents evaluation board user manuals application notes getting started guides software library documents errata see external links section links official arm documents
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Computer architecture
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planner programming language planner often seen publications planner although acronym programming language designed carl hewitt mit first published 1969 first subsets micro-planner pico-planner implemented essentially whole language implemented popler julian davies university edinburgh pop-2 programming language derivations qa4 conniver qlisp ether see scientific community metaphor important tools artificial intelligence research 1970s influenced commercial developments kee art two major paradigms constructing semantic software systems procedural logical procedural paradigm epitomized lisp mccarthy et al 1962 featured recursive procedures operated list structures logical paradigm epitomized uniform proof procedure resolution theorem provers robinson 1965 according logical paradigm “ cheating ” incorporate procedural knowledge green 1969 planner invented purposes procedural embedding knowledge hewitt 1971 rejection resolution uniform proof procedure paradigm robinson 1965 planner kind hybrid procedural logical paradigms combined programmability logical reasoning planner featured procedural interpretation logical sentences implication form p implies q procedurally interpreted following ways using pattern-directed invocation respect development planner influenced natural deductive logical systems especially one frederic fitch 1952 subset called micro-planner implemented gerry sussman eugene charniak terry winograd sussman charniak winograd 1971 used winograd natural-language understanding program shrdlu eugene charniak story understanding work thorne mccarty work legal reasoning projects generated great deal excitement field ai also generated controversy proposed alternative logic approach one mainstay paradigms ai sri international jeff rulifson jan derksen richard waldinger developed qa4 built constructs planner introduced context mechanism provide modularity expressions database earl sacerdoti rene reboh developed qlisp extension qa4 embedded interlisp providing planner-like reasoning embedded procedural language developed rich programming environment qlisp used richard waldinger karl levitt program verification earl sacerdoti planning execution monitoring jean-claude latombe computer-aided design richard fikes deductive retrieval steven coles early expert system guided use econometric model computers expensive single slow processor memories small comparison today planner adopted efficiency expedients including following gerry sussman eugene charniak seymour papert terry winograd visited university edinburgh 1971 spreading news micro-planner shrdlu casting doubt resolution uniform proof procedure approach mainstay edinburgh logicists university edinburgh bruce anderson implemented subset micro-planner called pico-planner anderson 1972 julian davies 1973 implemented essentially planner according donald mackenzie pat hayes recalled impact visit papert edinburgh become heart artificial intelligence logicland according papert mit colleague carl hewitt papert eloquently voiced critique resolution approach dominant edinburgh …and least one person upped sticks left papert mackenzie 2001 p 82 developments generated tension among logicists edinburgh tensions exacerbated uk science research council commissioned sir james lighthill write report ai research situation uk resulting report nowiki /nowiki lighthill 1973 mccarthy 1973 highly critical although shrdlu favorably mentioned pat hayes visited stanford learned planner returned edinburgh tried influence friend bob kowalski take planner account joint work automated theorem proving resolution theorem-proving demoted hot topic relic misguided past bob kowalski doggedly stuck faith potential resolution theorem proving carefully studied planner. ” according bruynooghe pereira siekmann van emden 2004 kowalski 1988 states recall trying convince hewitt planner similar sl-resolution planner invented purposes procedural embedding knowledge rejection resolution uniform proof procedure paradigm colmerauer roussel recalled reaction learning planner following way attending ijcai convention september ‘ 71 jean trudel met robert kowalski heard lecture terry winograd natural language processing fact use unified formalism left us puzzled time learned existence carl hewitt ’ programming language planner hewitt 1969 lack formalization language ignorance lisp fact absolutely devoted logic meant work little influence later research nowiki /nowiki colmerauer roussel 1996 fall 1972 philippe roussel implemented language called prolog abbreviation programmation en logique – french programming logic prolog programs generically following form special case backward-chaining planner prolog duplicated following aspects micro-planner prolog also duplicated following capabilities micro-planner pragmatically useful computers era saved space time use unique name assumption negation failure became questionable attention turned open systems hewitt de jong 1983 hewitt 1985 hewitt inman 1991 following capabilities micro-planner omitted prolog prolog include negation part raises implementation issues consider example negation included following prolog program program would unable prove p even though follows rules mathematical logic illustration fact prolog like planner intended programming language prove many logical consequences follow declarative reading programs work prolog valuable much simpler planner however need arose greater expressive power language prolog began include many capabilities planner left original version prolog
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Programming language topics
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portage software portage package management system originally created used gentoo linux also chrome os sabayon funtoo linux among others portage based concept ports collections gentoo sometimes referred meta-distribution due extreme flexibility portage makes operating-system-independent gentoo/alt project concerned using portage manage operating systems bsds macos solaris notable implementations gentoo/freebsd project ongoing effort called package manager specification project pms standardise document behaviour portage allowing ebuild tree gentoo system packages used alternative package managers paludis pkgcore goal specify exact set features behaviour package managers ebuilds serving authoritative reference portage portage similar bsd-style package management known ports originally designed freebsd ports mind portage written python programming language main utility defines gentoo although system known portage consists two main parts ebuild system emerge ebuild system takes care actual work building installing packages emerge provides interface ebuild managing ebuild repository resolving dependencies similar issues two therefore roughly relation rpm yum dpkg apt gtk+-based gui porthole available working portage also himerge gui stands haskell interface emerge portage characterized main function compiling source code packages user wishes install allows customization compiler target-application options fit system specifications user wishes functionalities related system management include allowing parallel package-version installation tracking cross-package dependencies managing database installed packages providing local ebuild repository synchronizing local portage tree remote repositories functionalities related individual package installation include specifying compilation settings target machine choosing package components portage distinguishes three levels stability ebuilds stable e.g. software works intended known security issues time release keyword masked mainly packages sufficiently tested target system architecture considered stable hard masked broken insecure packages emerge command-line tool heart portage command customizable many options modifiers emerge tool important utility accessing features portage command line program calculates manages dependencies executes ebuilds maintains local portage tree database installed packages compilation settings used ebuilds changed cflags environment variable based specifications individual computer user desire optimization emerge utility executes ebuilds sandbox environment way system protected software executed ebuild resulting binaries merged successful build sandboxed install emerge installs dependencies affected use flag-settings decide optional features included installing upgrading application emerge command also used download install precompiled binary files portage system offers use use flags allows users indicate software features would like include exclude building packages example use flag include dvd support available packages compiled flag enabled use flags affect dependencies required generally affecting optional features built given program compiled example packages use configure script use flag codice_1 would translate codice_2 specification use flags usual way configure programs gentoo use flags may set manually via user-friendly tools 'ufed use flag editor lists flags along description list available use flags available gentoo website use flag index gentoo default use binary packages package management systems like pacman employing instead format known ebuild whereas rpm binaries precompiled binaries ebuilds shell scripts variables functions contain description software instructions obtain configure compile install closely akin powerful .spec files distributed srpms 19,000 ebuilds available majority distributed gentoo mirrors new updated ebuilds obtained synchronizing local ebuild repository mirrors done executing command codice_3 historically gentoo provided pre-compiled binary packages many common programs especially lengthy compile mozilla firefox openoffice.org still installed emerge appending -bin package name instead install binary version gentoo binary packaging format .tbz2 file tar bzip2 compression additional metadata feature enables building binary packages one system using portage codice_4 codice_5 followed quick installation identical systems portage codice_6 codice_7 see portage features gentoo linux handbook information masking gentoo determines packages suitable system ebuilds designed different architectures experimental software usually masked manner prevents stable system installing without user intervention packages generally require testing often work fine said keyword masked i.e available systems accept_keywords make.conf entry starting character codice_8 codice_9 codice_10 codice_11 standard way unmask individual keyword masked package adding file full package name keyword codice_12 users make subdirectories well allowing custom organization example masked package multiple masked dependencies user could make directory name original masked package put mask files package dependencies directory scheme replaces older scheme codice_13 text file list packages known problems considered mature enough candidates stable hard masked one various package.mask files /usr/portage/profiles entries generally accompanied comment developers explaining reason mask
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Operating systems
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database seeding database seeding initial seeding database data seeding database process initial set data provided database installed especially useful want populate database data want develop future often automated process executed upon initial setup application data dummy data necessary data initial administrator account \migrations\configuration.cs appbundle/datafixtures/orm/customer.yml version 1 hautelook/alicebundle app/database/seeds/users.php
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Databases
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lua programming language lua meaning moon lightweight high-level multi-paradigm programming language designed primarily embedded use applications lua cross-platform since interpreter compiled bytecode written ansi c lua relatively simple c api embed applications lua originally designed 1993 language extending software applications meet increasing demand customization time provided basic facilities procedural programming languages complicated domain-specific features included rather included mechanisms extending language allowing programmers implement features lua intended general embeddable extension language designers lua focused improving speed portability extensibility ease-of-use development lua created 1993 roberto ierusalimschy luiz henrique de figueiredo waldemar celes members computer graphics technology group tecgraf pontifical catholic university rio de janeiro brazil 1977 1992 brazil policy strong trade barriers called market reserve computer hardware software atmosphere tecgraf clients could afford either politically financially buy customized software abroad reasons led tecgraf implement basic tools needed scratch lua predecessors data-description/configuration languages sol simple object language del data-entry language independently developed tecgraf 1992–1993 add flexibility two different projects interactive graphical programs engineering applications petrobras company lack flow-control structures sol del petrobras felt growing need add full programming power evolution lua language authors wrote lua 1.0 designed way object constructors slightly different current light flexible style incorporated data-description syntax sol hence name lua sol also portuguese word sun lua word moon lua syntax control structures mostly borrowed modula codice_1 codice_2 codice_3/codice_4 also taken influence clu multiple assignments multiple returns function calls simpler alternative reference parameters explicit pointers c++ neat idea allowing local variable declared need snobol awk associative arrays article published dr. dobb journal lua creators also state lisp scheme single ubiquitous data-structure mechanism list major influence decision develop table primary data structure lua lua semantics increasingly influenced scheme time especially introduction anonymous functions full lexical scoping several features added new lua versions versions lua prior version 5.0 released license similar bsd license version 5.0 onwards lua licensed mit license permissive free software licences almost identical lua commonly described multi-paradigm language providing small set general features extended fit different problem types lua contain explicit support inheritance allows implemented metatables similarly lua allows programmers implement namespaces classes related features using single table implementation first-class functions allow employment many techniques functional programming full lexical scoping allows fine-grained information hiding enforce principle least privilege general lua strives provide simple flexible meta-features extended needed rather supply feature-set specific one programming paradigm result base language light—the full reference interpreter 247 kb compiled—and easily adaptable broad range applications lua dynamically typed language intended use extension scripting language compact enough fit variety host platforms supports small number atomic data structures boolean values numbers double-precision floating point 64-bit integers default strings typical data structures arrays sets lists records represented using lua single native data structure table essentially heterogeneous associative array lua implements small set advanced features first-class functions garbage collection closures proper tail calls coercion automatic conversion string number values run time coroutines cooperative multitasking dynamic module loading classic hello world program written follows print hello world print 'hello world comment lua starts double-hyphen runs end line similar ada eiffel haskell sql vhdl multi-line strings comments adorned double square brackets factorial function implemented function example function factorial n end lua four types loops codice_2 loop codice_3 loop similar codice_7 loop numeric codice_8 loop generic codice_8 loop -- condition true condition end repeat condition first last delta -- delta may negative allowing loop count end generic codice_8 loop key value pairs _g end would iterate table codice_11 using standard iterator function codice_12 returns codice_13 also nested loop loop inside another loop local grid row ipairs grid end lua treatment functions first-class values shown following example print function behavior modified end future calls codice_14 routed new function lua lexical scoping old print function accessible new modified print lua also supports closures demonstrated function addto x end fourplus addto 4 print fourplus 3 -- prints 7 -- also achieved calling function following way print addto 4 3 -- calling returned function 'addto 4 argument 3 directly new closure variable codice_15 created every time codice_16 called new anonymous function returned always access codice_15 parameter closure managed lua garbage collector like object tables important data structures design built-in composite data type lua foundation user-created types conceptually similar associative arrays php dictionaries python hashes ruby perl table collection key data pairs data referenced key words hashed heterogeneous associative array tables created using codice_18 constructor syntax tables always passed reference see call sharing key index value except codice_13 nan including functions table often used structure record using strings keys use common lua features special syntax accessing fields using table store related functions act namespace tables automatically assigned numerical key enabling used array data type first automatic index 1 rather 0 many programming languages though explicit index 0 allowed numeric key codice_20 distinct string key codice_21 length table codice_22 defined integer index codice_23 codice_24 codice_13 codice_26 codice_13 moreover codice_28 codice_13 codice_23 zero regular array non-nil values 1 given codice_23 length exactly codice_23 index last value array holes nil values non-nil values codice_33 indices directly precedes codice_13 value may consider nil value end array table array objects using hash map emulate array normally slower using actual array however lua tables optimized use arrays help avoid issue extensible semantics key feature lua metatable concept allows lua tables customized powerful ways following example demonstrates infinite table codice_23 codice_36 give codice_23-th fibonacci number using dynamic programming memoization fibs 1 1 -- initial values fibs 1 fibs 2 setmetatable fibs although lua built-in concept classes object-oriented programming achieved using two language features first-class functions tables placing functions related data table object formed inheritance single multiple implemented using metatable mechanism telling object look nonexistent methods fields parent object concept class techniques rather prototypes used similar self javascript new objects created either factory method constructs new objects scratch cloning existing object lua provides syntactic sugar facilitate object orientation declare member functions inside prototype table one use equivalent calling class methods also makes use colon equivalent creating basic vector object vector.__index vector function vector new x z -- constructor end function vector magnitude -- another method end local vec vector new 0 1 0 -- create vector print vec magnitude -- call method output 1 print vec.x -- access member variable output 0 lua programs interpreted directly textual lua file compiled bytecode run lua virtual machine compilation process typically invisible user performed run-time done offline order increase loading performance reduce memory footprint host environment leaving compiler lua bytecode also produced executed within lua using codice_38 function string library codice_39 functions lua version 5.3.4 implemented approximately 24,000 lines c code like cpus unlike virtual machines stack-based lua vm register-based therefore closely resembles actual hardware design register architecture avoids excessive copying values reduces total number instructions per function virtual machine lua 5 one first register-based pure vms wide use perl's parrot android dalvik two well-known register-based vms example bytecode listing factorial function defined shown codice_40 5.1 compiler lua intended embedded applications provides c api purpose api divided two parts lua core lua auxiliary library lua api design eliminates need manual reference management c code unlike python api api like language minimalistic advanced functionality provided auxiliary library consists largely preprocessor macros assist complex table operations lua c api stack based lua provides functions push pop simple c data types integers floats etc stack well functions manipulating tables stack lua stack somewhat different traditional stack stack indexed directly example negative indices indicate offsets top stack example −1 top recently pushed value positive indices indicate offsets bottom oldest value marshalling data c lua functions also done using stack call lua function arguments pushed onto stack codice_41 used call actual function writing c function directly called lua arguments read stack example calling lua function c int main void running example gives c api also provides special tables located various pseudo-indices lua stack codice_42 prior lua 5.2 globals table codice_11 within lua main namespace also registry located codice_44 c programs store lua values later retrieval possible write extension modules using lua api extension modules shared objects used extend functionality interpreter providing native facilities lua scripts lua side module appears namespace table holding functions variables lua scripts may load extension modules using codice_45 like modules written lua growing collection modules known rocks available package management system called luarocks spirit cpan rubygems python eggs prewritten lua bindings exist popular programming languages including scripting languages c++ number template-based approaches automatic binding generators video game development lua widely used scripting language game programmers perhaps due perceived easiness embed fast execution short learning curve 2003 poll conducted gamedev.net showed lua popular scripting language game programming 12 january 2012 lua announced winner front line award 2011 magazine game developer category programming tools large number non-game applications also use lua extensibility luatex implementation tex type-setting language redis key-value database nginx web server scribunto extension lua available scripting language mediawiki software powers wikipedia wikis among uses allowing integration data wikidata articles powering
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Programming language topics
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financial information exchange financial information exchange fix protocol electronic communications protocol initiated 1992 international real-time exchange information related securities transactions markets trillions dollars traded annually nasdaq alone financial service entities investing heavily optimizing electronic trading platforms employing direct market access dma increase speed financial markets managing delivery trading applications keeping latency low increasingly requires understanding fix protocol fix protocol specification originally authored 1992 robert bob lamoureux chris morstatt enable electronic communication equity trading data fidelity investments salomon brothers fix initially addressed information broker-dealers institutional clients time information communicated verbally telephone fidelity realized information broker-dealers could routed wrong trader simply lost parties hung phones wanted communications replaced machine-readable data could shared among traders analyzed acted stored example broker-dealers call indication interest ioi buy sell block stock fix initiative created new messages ioi according fix trading community fix become de facto messaging standard pre-trade trade communication global equity markets expanding post-trade space support straight-through processing well continuing expand foreign exchange fixed income derivatives markets fix trading community non-profit industry-driven standards body mission address business regulatory issues impacting multi-asset trading across global financial markets increased use standards including fix protocol messaging language delivering operational efficiency increased transparency reduced costs risk market participants fix widely used sell side institutions well buy side brokers/dealers financial markets among users mutual funds investment banks brokers stock exchanges ecns see fix trading community organization extensive list major fix users fix become standard electronic protocol pre-trade communications trade execution although mainly used equity transactions front office area bond derivatives fx-transactions also possible one could say whereas swift standard back office messaging fix standard front office messaging however today membership fix protocol ltd. extending fix block trade allocation phases trading process every market virtually every asset class originally fix standard monolithic including application layer semantics message encoding session layer single technical specification remained monolithic fix version 4.2 thereafter message encodings session layer specifications began split separate documents ultimately fix evolved family related technical standards message encoding called presentation layer open systems interconnection model osi model responsible wire format messages original fix message encoding known tagvalue encoding field consists unique numeric tag value tag identifies field semantically therefore messages self-describing tagvalue encoding character-based using ascii codes message fields delimited using ascii 01 start header character composed header body trailer fix.4.4 header contained three fields 8 codice_1 9 codice_2 35 codice_3 tags fixt.1.1 fix.5.0 header contains five mandatory fields one optional field 8 codice_1 9 codice_2 35 codice_3 49 codice_7 56 codice_8 1128 codice_9 present must 6th position content body message specified tag 35 codice_3 message type defined header last field message tag 10 fix message checksum always expressed three-digit number e.g codice_11 header+body+trailer fix content example fix message execution report pipe character used represent soh character fixmessage body length 9 correct checksum 10 checked using source available quickfix open-source fix implementation fix messages formed number fields field tag value pairing separated next field delimiter soh 0x01 tag integer indicates meaning field value array bytes hold specific meaning particular tag e.g tag 48 securityid string identifies security tag 22 idsource integer indicates identifier class used values may plain text encoded pure binary case value preceded length field fix protocol defines meanings tags leaves range tags reserved private use consenting parties fix protocol also defines sets fields make particular message within set fields mandatory others optional ordering fields within message generally unimportant however repeating groups preceded count encrypted fields preceded length message broken three distinct sections head body tail fields must remain within correct section within section position may important fields act delimiters stop one message running next final field fix message tag 10 checksum two main groups messages—admin application admin messages handle basics fix session allow session started terminated recovery missed messages application messages deal sending receiving trade-related information order request information current state subsequent execution order body length character count starting tag 35 included way tag 10 excluded soh delimiters count body length. br example soh replaced by'| br body length 65. br soh delimiter end tag=value belongs tag checksum fix message always last field message composed three characters tag 10 given summing ascii value characters message except checksum field performing modulo 256 resulting summation example message summation ascii values including soh character value 1 ascii table results 4158 performing modulo operation gives value 62 since checksum composed three characters 062 used fixml xml schema fix messages semantically equivalent tagvalue encoded messages takes advantage xml parser technology fixml commonly used back-office clearing applications rather trading simple binary encoding defines wire format using primitive data types native computing systems message encoding decoding therefore much lower latency character-based protocols since translation needed put data format computers use aside latency advantages performance deterministic sbe messages constrained templates fixed-length data elements preferred another consequence fields generally fixed position message filters routers need crack entire message access key fields sbe developed fix high performance working group support high performance trading tagvalue encoding deemed longer fit-for-purpose since character based rather binary variable-length fields messages result non-deterministic performance unlike tagvalue fixml sbe message self-describing data sent wire minimal header identify template controls message metadata describes message layout exchanged out-of-band peers fix trading community publishes xml schema sbe message schemas message schema may contain number message templates template describes fields constitute message additionally schema provides listing simple composite data types may reused number fields fix trading community also developed standard mappings fix message protocols including session layer responsible message exchange including checkpoint recovery mechanisms original fix session protocol name since part monolithic specification covering application layer semantics message encoding well however starting fix version 5.0 session layer split independent specification introduction fixt fixt largely original unnamed session layer version 4.x offered one significant innovation -- provided mechanism mix fix application layer versions common session version current fixt version 1.1 theoretically fixt transport independent however usually employed transmission control protocol tcp fixt point-to-point protocol guarantees message delivery directions messages sent direction carry message sequence number message header communication fault peer may request retransmission missed messages message delivery supported even event disconnection later reestablishment session implement session establishment guaranteed delivery fixt classic fix 4.x define session message types fixp developed fix high performance working group meet needs high performance trading primary need low latency message encoding decoding control message delivery guarantees provide low latency binary message encodings supported session layer application messages actual wire format abstracted fixp specification users may select fix encoding choice long peers agree protocol use early development used simple binary encoding fixp covers point-to-point multicast use cases common primitives point-to-point session established peers negotiate delivery guarantees among following choices delivery guarantees may asymmetrical example trader may enter orders idempotent flow executions returned recoverable flow fast moving markets delay inherent retransmission often undesirable resulting missed opportunities bad trades diagram fix messaging looks buyside/customer sellside/supplier latest version fix protocol implements transport independence permitting multiple versions application messages carried single version transport independent fix session fixt.1.1 higher transport independence also paves way transport protocols message queues web services used instead traditional fix tcp fix supports algorithmic trading use fix algorithmic trading definition language fixatdl fix protocol limited released fast protocol stands fix adapted streaming fast binary protocol used mostly sending multicast market data via udp connections many companies offer fix testing products services
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Internet protocols
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common lisp music clm originally acronym common lisp music music synthesis signal processing package music v family created bill schottstaedt runs number various lisp implementations part snd audio editor using scheme ruby forth also realtime implementation snd-rt developed kjetil s. matheussen software used digitally stretch beethoven 9th symphony create leif inge 9 beet stretch
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Programming language topics
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mark adler mark adler born april 3 1959 american software engineer best known work field data compression author adler-32 checksum function co-author zlib compression library gzip contributed info-zip participated developing portable network graphics png image format adler also spirit cruise mission manager mars exploration rover mission adler born miami florida raised child david bertha adler adler earned bachelor science mathematics master science electrical engineering degrees university florida 1981 1985 respectively 1990 adler earned ph.d. physics california institute technology doctorate adler worked hughes aircraft space communications group working diverse projects including analysis effects x-ray bursts satellite cables development new error-correcting codes designing automobile anti-theft key digital image video compression research wavelets mpeg-2 1992 1995 adler lead mission engineer cassini–huygens mission afterwards became mars exploration program architect jet propulsion laboratory jpl 1996 1998 meant adler responsible planning mars exploration missions 2001 well handling inter-project engineering issues missions flight development time 1999 early 2000 adler mission systems manager chief engineer mars sample return project launch three missions 2003 2005 bring martian samples back earth 2008 project canceled failure mars polar lander adler initiated led three-and-a-half-week study concept later selected mars exploration rover mer mission 2003 served deputy mission system manager acting project engineer deputy assembly test launch operations manager landing site selection engineer spirit mission manager adler currently project chief low density supersonic decelerator adler instrument-rated private pilot certified scuba diver amateur theater actor lives diana st. james la cañada california two children joshua zachary st. james works california institute technology acts directs theatrical performances together co-author jean-loup gailly adler received 2009 usenix software tools user group stug award contributions floss algorithms data compression
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Operating systems
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list in-memory databases article list in-memory database system software
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Databases
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spacecraft command language spacecraft command language satellite control language spacecraft control language systems test operation language stol satellite test operation language etc computer command language commanding spacecraft mission systems ultimately languages used command remote spacecraft telecommands also used development verification onboard systems prototype engineering model flight hardware software ground systems prior launch spacecraft command languages typically written format similar human languages contrast telecommand protocols usually binary formats although may displayed hexadecimal broken labelled fields command displays spacecraft command languages scl plexil executed spacecraft onboard executive nasa gsfc systems test operation language stol functional requirements language description 1978 illustrates concept systems test operation language stol provides means user communication payloads applications programs ground system elements systems operation language enables operator user communicate command computer system system interprets high level language directive user performs indicated action executing program printing snapshot sending payload command using stol payload test operations personnel may relieved repetitive tasks ensuring recurring fixed sequences operations always performed exactly order guaranteeing repeatability test procedures project operations control center pocc operations original language acronym stol applied gsfc systems test operation language designed 1970s nasa goddard space flight center provide standardized language functionality previously represented least three satellite operation language efforts gsfc various stols created locations mission-specific site-specific names proliferated extent jargon interpreter program prototyped one gsfc convert english statements limited set mstol directives plans stol dialects.. languages later developed offered private companies part satellite control software suites following examples show natural language cstol commands lower-level spacecraft commands translated particular spacecraft first two examples show two different cstol commands translated spacecraft command indicating spacecraft command takes different values argument last example cstol command translated another cstol command would translated spacecraft command still-human-readable textual format command uplinked as-is spacecraft ability read text format otherwise command translated packed binary representation ground prior uplink
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Programming language topics
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symbolic data analysis symbolic data analysis sda extension standard data analysis symbolic data tables used input symbolic objects made output result data units called symbolic since complex standard ones contain values categories also include internal variation structure sda based four spaces space individuals space concepts space descriptions space symbolic objects space descriptions models individuals space symbolic objects models concepts
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Programming language topics
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security automated teller machines automated teller machines atms first introduced 1939 2015 3 million units installed worldwide number atm units increase machines prone hacker attacks fraud robberies security breaches past main purpose atms deliver cash form bank notes debit corresponding bank account however atms becoming complicated serve numerous functions thus becoming high priority target robbers hackers modern atms implemented high-security protection measures work complex systems networks perform transactions data processed atms usually encrypted hackers employ discreet hacking devices hack accounts withdraw account balance alternative unskilled robbers threaten bank patrons weapon loot withdrawn money account main article atm fraud atm vandals either physically tamper atm obtain cash employ credit card skimming methods acquire control user credit card account credit card fraud done inserting discreet skimming devices keypad credit card reader alternative way credit card fraud identify pin directly devices cameras concealed near keypad validation on-line pin occurs terminal question connected central database pin supplied customer always compared recorded reference pin financial institutions however one disadvantage malfunction network renders atm unusable fixed off-line pin validation atm connected central database condition off-line pin validation atm able compare customer entered pin pin reference terminal must able perform cryptographic operations must required encryption keys disposal offline validation scheme extremely slow inefficient offline pin validation obsolete atms connected central server protected wireless networks three pin procedures operation high security interchange transaction supplied pin encrypted entry terminal step secret cryptographic key used addition transaction elements encrypted pin transmitted acquirer system encrypted pin routed acquirer system hardware security module within pin decrypted cryptographic key used interchange decrypted key immediately reencrypted routed issuer system normal communications channels lastly routed pin decrypted issuer security module validated basis techniques on-line local pin validation different transaction methods used shared atms regards encipherment pin message authentication among called zone encryption method trusted authority appointed operate behalf group banks could interchange messages atm payment approvals successful communication banks atms incorporation cryptographic module usually called security module critical component maintaining proper connections banks machines security module designed tamper resistant security module performs plethora functions among pin verification pin translation interchange key management message authentication use pin interchanges causing concerns security pin translated security module format used interchange moreover security module generate protect maintaining keys associated user network personal verification process begins user supply personal verification information information include pin provided customer information recorded bank account cases storage cryptographic key bank card called personal key pk personal identification processes done authentication parameter ap capable operating two ways first option ap time invariant second option ap time variant case ip based time variant information transaction request message case ap used message authentication code mac use message authentication made recourse find stale bogus messages might routed communication path detection modified messages fraudulent traverse non-secure communication systems cases ap serves two purposes security breaches electronic funds transfer systems done without delimiting components electronic funds transfer systems three components communication links computers terminals atms first communication links prone attacks data exposed passive means direct means device inserted retrieve data second component computer security different techniques used acquire access computer accessing via remote terminal peripheral devices card reader hacker gained unauthorized access system programs data manipulated altered hacker terminal security significant component cases cipher keys reside terminals absence physical security abuser may probe key substitutes value
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Computer security
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video door-phone video door-phone also known video door entry video intercom stand-alone intercom system used manage calls made entrance building residential complex detached family home workplace etc access controlled audiovisual communication inside outside main feature video door entry enables person indoors identify visitor wish engage conversation and/or open door allow access person calling video door entry consists outside indoor elements outdoor panel outside electronic lock release indoor monitor outdoor panel street panel installed beside entrance door gateway incorporates different elements ready use climate conditions one several pushbuttons make call usually one per home apartment micro camera adapted night vision capture image caller microphone pick voice speaker reproduce voice occupant indoors video door entry panel may include push buttons call homes offices camera capture street scene video entry monitor allows occupant see called talk visitor open door installed indoors monitor consists screen showing image person calling microphone earpiece conversation pushbutton trigger door lock release communication set full duplex electric door release device installed door lock operated inside building lift latch clear way visitor several variations basic format addition outdoor panels one pushbutton per apartment possible find others numeric keypad case designed large residential installations homes identified codes others built-in cardholders panels even small screens guide user facilitate entry people disabilities video entry monitors earpiece similar telephone handset others hands-free examples monitors memories store image every time someone calls door touchscreen video entry systems video door phone classified two possible classification 1 security layers level 1 security – security layer added vdp system community entrance layer given guard directly verify entry visitor community systems community level b level 2 security also known lobby security – get access lobby apartment case visitor dial number flat flat owner allows access visitor lobby entrance c. level 3 security case visitor communicates outdoor camera front house door villa gate 2 technologies classification a. standalone – standalone vdp device used villas individual home owners types technology standalone vdp – i. analog vdp – analog display camera ii.connected digital vdp – digital lcd display digital camera usually image capture video capturing ability bell pressed case normally additional camera integration also allowed iii wireless video door bell vdb camera units gets connected interned router allows communication ones mobile tablet top communicate visitor b. multi-apartment- solution mass housing scenario i. analog multi-apartment systems – analog vdp providing 3 tier security ii ip vdp multi-apartment system – ip vdp 3 tier security integration bms building management system security systems like intrusion cctv building security cases even home automation visitor presses one outdoor panel pushbuttons built-in camera connected image captured outdoors appears monitor screen connection takes place automatically need activate equipment one essential elements video door entry point person inside building open door wish begin conversation usually secret heard users facility equipment also disconnects automatically set time elapsed video entry system whole runs low voltage energy building ’ trunk many terminals currently market ready accept extensions making monitor small automatic function control centre user view one several additional cameras installed access points trigger light switches open second door etc video door entry systems commonly found integrated different access control systems means elements installed outdoor panel allow certain previously authorised users access premises common means proximity cards fingerprint readers keypad secret numbers even bluetooth triggered mobile phone different equipment sets currently found market make use accessible people different disabilities thinking visually impaired outdoor panel may include information braille alongside pushbuttons voice synthesiser also added indicates door opened people hearing impairment outdoor panel may include screen icons signalling communication status user calling someone speaking indoors opening door also type user mind monitor may fitted inductive loop element interacts conventional hearing aids facilitate conversation outside without presence noticed users kit also includes visual audio call alerts
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Computer security
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andy gavin andrew scott andy gavin born june 11 1970 american video game programmer designer entrepreneur novelist video game industry known co-founding video game company naughty dog childhood friend jason rubin 1986 games crash bandicoot jak daxter released critical acclaim sophistication naughty dog technology often credited gavin background lisp mit artificial intelligence laboratory gavin earned bachelor science degree neurobiological science haverford college gavin studied ph.d. massachusetts institute technology carried research jet propulsion laboratory mars rover vision project advisor rod brooks still student gavin learned computer programming language lisp influences m.i.t work lead develop number custom programming languages improved quality graphics controls sounds artificial intelligence naughty dog video games gavin rubin sold first video game math jam 1985 1989 sold keef thief electronic arts early '90s fighting game way warrior led multi-title deal universal interactive studios auspices universal deal produced multi-million selling crash bandicoot series 1994 1999 later segued critically acclaimed jak daxter series games end 2000 rubin gavin sold naughty dog sony computer entertainment america scea created 14 naughty dog games including math jam 1985 ski crazed 1986 dream zone 1987 keef thief 1989 rings power 1991 way warrior 1994 crash bandicoot 1996 1997 1998 crash team racing 1999 2001 jak ii 2003 jak 3 2004 2005 together games sold 35 million units generated 1 billion revenue naughty dog gavin developed two lisp dialects use game development gool game object oriented lisp successor goal game oriented assembly lisp represented departure mainstream terms language choice featured innovations design shortly leaving naughty dog 2004 gavin co-founded new internet startup called flektor former business partner jason rubin former hbo executive jason r. kay may 2007 company sold fox interactive media division news corp. fox described company next-generation web site provides users suite web-based tools transform photos videos dynamic slideshows postcards live interactive presentations video mash-ups october 2007 flektor partnered sister company myspace mtv provide instant audience feedback via polls interactive myspace mtv presidential dialogues series then-presidential candidate senator barack obama gavin left fox interactive media 2008 2009 announced return video game business naughty dog co-founder jason rubin formed new social game startup called monkey gods working new version snood along casual word game called monkwerks recent years gavin turned novel writing first novel dark historical fantasy darkening dream published december 2011 second novel untimed involves time travel released december 19 2012
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Programming language topics
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david wang hacker david wang jail break developer mobile phone hacker apple phone hacking competition hacked iphone use android apps platform
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Computer security
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schools interoperability framework schools interoperability framework systems interoperability framework uk sif data-sharing open specification academic institutions kindergarten workforce specification used primarily united states canada uk australia new zealand however increasingly implemented india elsewhere specification comprises two parts xml specification modeling educational data specific educational locale north america australia uk service-oriented architecture soa based direct brokered restful-models sharing data institutions international shared locales sif product industry initiative enables diverse applications interact share data sif estimated used 48 us states 6 countries supporting five million students specification started maintained specification body schools interoperability framework association renamed access learning community a4l 2015 traditionally standalone applications used public school districts limitation data isolation difficult access share data often results redundant data entry data integrity problems inefficient incomplete reporting cases student information appear multiple places may identical example decision makers may working incomplete inaccurate information many district site technology coordinators also experience increase technical support problems maintaining numerous proprietary systems sif created solve issues schools interoperability framework sif began initiative chiefly championed initially microsoft create blueprint educational software interoperability data access designed initiative drawing upon strengths leading vendors k-12 market enable schools professionals build manage upgrade systems endorsed close 20 leading k-12 vendors student information library transportation food service applications first pilot sites began summer 1999 first sif-based products began show 2000 beginning clear approach would become national standard united states sif edi vying position 2000 sif began taking lead 2002 2000 national school boards association held panel discussion annual meeting topic sif 2007 united kingdom becta championed adoption sif national standard schools data interchange 2008 announced uk standard become known systems interoperability framework reflects intention uk develop sif used organizations beyond schools sif specification supported a4l community a4l members collaborate variety technical solutions standards include limited schools interoperability framework members include districts states vendors non-profits various government agencies sif pains challenges come soa specification data model building specifications via consensus everyone always happy sometimes end product n't perfect also given moving parts modeling entire k12 enterprise specification many points possible failure particular sif record-level automated system moving standardized data one source another heterogeneous environment out-of-the-box interoperability ease use implementation part 12-18 month focus 2007 2009 sif 2.x relied using broker called zone integration server zis manage communication applications sif 3.x sif 2.8+ allows brokered direct communication applications rather application vendor try set separate connection every application sif defined set rules definitions share data within sif zone — environment logical grouping applications software application agents communicate central communication point zones managed enterprise data broker sometimes called zone integration server zis single zis manage multiple zones however current infrastructure specification supports restful connections directly applications and/or utilizing brokered environment data travels applications series standardized messages queries events written xml json sent using internet protocols sif specification defines events choreography allows data move back forth applications direct sif allow one application communicate directly another via simple rest calls put post get delete resources ideal simple environments two maybe three players complex choreographies necessary easier implement brokered environment two- three-node situations sif agents pieces software exist either internal application installed next sif agents function extensions application serve intermediary software application sif zone brokered environments broker keeps track agents registered environment zones manages transactions agents enabling provide data respond requests broker controls access routing security within system standardization behavior agents broker means sif add standard functionality zone simply adding sif-enabled applications time vertical interoperability situation sif agents different levels organization communicate using sif zone vertical interoperability involves data collection multiple agents upward publishing information multiple agents downward example state-level data warehouse may listen changes district-level data warehouses update database accordingly state entity may wish publish teacher certification data districts three pieces sif specification deal directly vertical interoperability student locator object vertical reporting object data warehouse object good example would century consultants sis agent working pearson slf agent sending student data state agency getting student testing identifiers return sif designed rest soap namespaces web service standards mature today result robust soa vetted current soap specifications use soap ws standards 2.0 sif web services specification began process joining two worlds 3.0 infrastructure specification completes transformation soa specification using modern tools 2.0 web services specification allows generalized xml messaging structures typically found enterprise messaging systems use concept enterprise service bus web service standards also designed support secure public interfaces xml appliances make setup configuration easier sif 2.0 web services specification allows use web services communicate zone 3.0 infrastructure allows data payload moved across designed around restful design patterns allows brokered direct exchanges restful manner utilizing either xml json payloads starting sif 3.0 sif specification relies entirely-unless impossible practical- common education data standards ceds controlled vocabulary element definition allows transport ceds wire compatible ceds-compliant data sets similar standard liss supports vendor integration 'within school site overcomes limitations school elected use zone integration server requirement sif 3.x implementations liss lightweight interoperability standard schools connects primarily smaller 'local modules timetabling roll call reporting others main admin system given school site liss works either across web via local network simpler format sifa also working closely postsecondary electronic standards council pesc scorm standards organizations august 2013 sif association announced release sif implementation specification 3.0 sif implementation specification north america 3.0 made globally utilized reference infrastructure north america data model focusing supporting common education data standards ceds initiative new 3.0 infrastructure allows transport various data models including global sif communities well data numerous “ alphabet soup ” data initiatives populating education landscape essence – education utilize “ one wire one plug ” – never-ending proprietary api ’ “ one ” connections specification fully supports restful web services soap-based protocols australian 3.4 data model specification came fall 2016 well 3.1.2 release global sif infrastructure version 2.8 specification last 2.x version sif sif implementations united states abroad 2.x deployments a4l community released new version sif specification called unity use best objects 3.x specification foundation 2.8 specification able run either 3.x infrastructure 2.x infrastructure boon thousands districts many states using sif 2 infrastructure allows clean migration path utilizing modern restful architectures desired sif 3.2 release includes sif xpress roster sif xpress student record exchange sre result work done various members association vendors agencies regional centers easily adopted easier implement sub-set specification handles roster basic uses cases access learning community recently started taking strong leadership education privacy space globally association created supports organization called student data privacy consortium sdpc working closely national australian privacy efforts
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Computer architecture
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foremost software foremost forensic data recovery program linux used recover files using headers footers data structures process known file carving although written law enforcement use freely available used general data recovery tool foremost created march 2001 duplicate functionality dos program carvthis use linux platform foremost originally written special agents kris kendall jesse kornblum u.s. air force office special investigations 2005 program modified nick mikus research associate naval postgraduate school center information systems security studies research part master thesis modifications included improvements foremost accuracy extraction rates foremost designed ignore type underlying filesystem directly read copy portions drive computer memory takes portions one segment time using process known file carving searches memory file header type matches ones found foremost configuration file match found writes header data following file stopping either footer found file size limit reached foremost used command-line interface graphical user interface option available able recover specific filetypes including jpg gif png bmp avi exe mpg wav riff wmv mov pdf ole doc zip rar htm cpp configuration file usually found /usr/local/etc/foremost.conf used define additional file types foremost used recover data image files directly hard drives use ext3 ntfs fat filesystems foremost also used via computer recover data iphones
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Computer security
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dnalinux dnalinux linux distribution bioinformatics software included live cd based slax includes programs like blast emboss dnalinux made genes digitales quilmes national university argentina
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Operating systems
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proof assistant computer science mathematical logic proof assistant interactive theorem prover software tool assist development formal proofs human-machine collaboration involves sort interactive proof editor interface human guide search proofs details stored steps provided computer theorem prover museum initiative conserve sources theorem prover systems future analysis since important cultural/scientific artefacts sources many systems mentioned popular front-end proof assistants emacs-based proof general developed university edinburgh coq includes coqide based ocaml/gtk isabelle includes isabelle/jedit based jedit isabelle/scala infrastructure document-oriented proof processing
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Programming language topics
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simulation software simulation software based process modeling real phenomenon set mathematical formulas essentially program allows user observe operation simulation without actually performing operation simulation software used widely design equipment final product close design specs possible without expensive process modification simulation software real-time response often used gaming also important industrial applications penalty improper operation costly airplane pilots nuclear power plant operators chemical plant operators amock actual control panel connected real-time simulation physical response giving valuable training experience without fear disastrous outcome advanced computer programs simulate power system behavior weather conditions electronic circuits chemical reactions mechatronics heat pumps feedback control systems atomic reactions even complex biological processes theory phenomena reduced mathematical data equations simulated computer simulation difficult natural phenomena subject almost infinite number influences one tricks developing useful simulations determine important factors affect goals simulation addition imitating processes see behave different conditions simulations also used test new theories creating theory causal relationships theorist codify relationships form computer program program behaves way real process good chance proposed relationships correct general simulation packages fall two categories discrete event continuous simulation discrete event simulations used model statistical events customers arriving queues bank properly correlating arrival probabilities observed behavior model determine optimal queue count keep queue wait times specified level continuous simulators used model wide variety physical phenomena like ballistic trajectories human respiration electric motor response radio frequency data communication steam turbine power generation etc simulations used initial system design optimize component selection controller gains well model based design systems generate embedded control code real-time operation continuous simulation used operator training off-line controller tuning four main renowned simulation approaches event-scheduling method activity scanning process- interaction three-phase approach comparison following noted event-scheduling method simpler two phases cs bs allow program run faster since scanning condition nal events advantages also tells us something disadvantages method since two phase events mixed bs cs method parsimony means hard enhance pidd,1998 activity scanning approach also simpler three-phase method since calendar support parsimonious modeling however approach much slower three-phase since treats activities treated conditional hand executive two phases usually approach confused three-phase method pidd 1998 process- interaction “ share two common advantages first avoid programs slow run second avoid need think possible logical consequences event ” pidd 1998 yet pidd 1998 claims approach suffers deadlock problem approach attractive novice modelers although schriber et al 2003 says “ process interaction understood elite group individuals beyond reach ordinary programmers ” fact schriber et al 2003 .adds “ .multi- threaded applications talked computer science classes rarely used broader community ” indicates implementation process-interaction difficult implement obvious contradiction previous quote due mix process interaction approach transaction-flow approach see complete idea origins transaction-flow best stated schriber et al 2003 primordial soup gordon simulator arose gordon ’ transaction flow world-view cleverly disguised form process interaction put process interaction approach within grasp ordinary users gordon one great packaging jobs time devised set building blocks could put together build flowchart graphically depicted operation system modeling paradigm flow elements system readily visible focus whole approach three-phase approach allows “ simulate parallelism whilst avoiding deadlock ” pidd cassel 1998 yet three-phase scan schedule bound activities scans conditional activities slow yet many forgo time spent return solving deadlock problem fact three-phase used distributed systems whether talking operating systems databases etc different names among three-phase commit see tanenbaum steen 2002 electronics simulation software utilizes mathematical models replicate behaviour actual electronic device circuit essentially computer program converts computer fully functioning electronics laboratory electronics simulators integrate schematic editor spice simulator onscreen waveforms make “ what-if ” scenarios easy instant simulating circuit ’ behaviour actually building greatly improves efficiency provides insights behavior stability electronics circuit designs simulators use spice engine simulates analog digital mixed circuits exceptional power accuracy also typically contain extensive model device libraries simulators typically printed circuit board pcb export capabilities essential design testing circuits primary application electronic circuit simulation strictly analog electronics circuit simulators include analog event-driven digital simulation capabilities known mixed-mode simulators means simulation may contain components analog event driven digital sampled-data combination entire mixed signal analysis driven one integrated schematic digital models mixed-mode simulators provide accurate specification propagation time rise/fall time delays event driven algorithm provided mixed-mode simulators general purpose supports non-digital types data example elements use real integer values simulate dsp functions sampled data filters event driven algorithm faster standard spice matrix solution simulation time greatly reduced circuits use event driven models place analog models mixed-mode simulation handled three levels primitive digital elements use timing models built-in 12 16 state digital logic simulator b subcircuit models use actual transistor topology integrated circuit finally c in-line boolean logic expressions exact representations used mainly analysis transmission line signal integrity problems close inspection ic ’ i/o characteristics needed boolean logic expressions delay-less functions used provide efficient logic signal processing analog environment two modeling techniques use spice solve problem third method digital primitives use mixed mode capability methods merits target applications fact many simulations particularly use a/d technology call combination three approaches one approach alone sufficient order properly understand operation programmable logic controller plc necessary spend considerable time programming testing debugging plc programs plc systems inherently expensive down-time often costly addition plc programmed incorrectly result lost productivity dangerous conditions plc simulation software valuable tool understanding learning plcs keep knowledge refreshed date plc simulation provides users ability write edit debug programs written using tag-based format many popular plcs use tags powerful method programming plcs also complex plc simulation integrates tag-based ladder logic programs 3d interactive animations enhance user ’ learning experience interactive animations include traffic lights batch processing bottling lines using plc simulation plc programmers freedom try what-if scenarios changing ladder logic instructions programs re-running simulation see changes affect plc operation performance type testing often feasible using hardwired operating plcs control processes often worth hundreds thousands – millions dollars sheet metal forming simulation software utilizes mathematical models replicate behavior actual metal sheet manufacturing process essentially computer program converts computer fully functioning metal manufacturing prediction unit sheet metal forming simulation prevents metal factories defects production lines reduces testing expensive mistakes improving efficiency metal forming process metal casting simulation currently performed finite element method simulation software designed defect-prediction tool foundry engineer order correct and/or improve his/her casting process even prototype trials produced idea use information analyze predict results simple effective manner simulate different processes software would normally following specifications interaction different network entities defined various communication protocols network simulation software simulates behavior networks protocol level network protocol simulation software used develop test scenarios understand network behavior certain protocol messages compliance new protocol stack implementation protocol stack testing simulators based telecommunications protocol architecture specifications developed international standards body itu-t ieee output protocol simulation software detailed packet traces events logs etc understanding computers made many components component many different attributes different manufacturer accordingly computer performance evaluation another application simulation would paramount significance particularly since experimenting possible scenarios nearly impossible commercial simulation packages caught fact two packages offered application namely anylogic 5.0 visual simulation environment
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Programming language topics
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domainkeys identified mail domainkeys identified mail dkim email authentication method designed detect forged sender addresses emails email spoofing technique often used phishing email spam dkim allows receiver check email claimed come specific domain indeed authorized owner domain achieves affixing digital signature linked domain name outgoing email message recipient system verify looking sender public key published dns valid signature also guarantees parts email possibly including attachments modified since signature affixed usually dkim signatures visible end-users affixed verified infrastructure rather message authors recipients dkim internet standard defined rfc 6376 dated september 2011 updates rfc 8301 rfc 8463 need email validated identification arises forged addresses content otherwise easily created widely used spam phishing email-based fraud example fraudster may send message claiming sender example.com goal convincing recipient accept read email difficult recipients establish whether trust message system administrators also deal complaints malicious email appears originated systems dkim provides ability sign message allows signer author organization communicate emails considers legitimate directly prevent disclose abusive behavior dkim also provides process verifying signed message verifying modules typically act behalf receiver organization possibly hop independent simple mail transfer protocol smtp routing aspects operates rfc 5322 message—the transported mail header body—not smtp envelope defined rfc 5321 hence dkim signatures survives basic relaying across multiple mtas signing organization direct handler message author submission site intermediary along transit path indirect handler independent service providing assistance direct handler signing modules insert one codice_1 header fields possibly behalf author organization originating service provider specification allows signers choose header fields sign codice_2 field must always signed resulting header field consists list codice_3 parts example tags used relevant ones b actual digital signature contents headers body mail message bh body hash signing domain selector header body contribute signature first message body hashed always beginning possibly truncated given length may zero second selected header fields hashed order given h. repeated field names matched bottom header upward order codice_4 fields inserted header non-existing field matches empty string adding field name break signature codice_1 field signature created bh equal computed body hash b equal empty string implicitly added second hash albeit name must appear h — refers another preexisting signature hashes text canonicalized according relevant c algorithms result encryption signer private key encoding using base64 b. algorithms fields body length meant chosen assure unambiguous message identification still allowing signatures survive unavoidable changes going occur transit data integrity implied receiving smtp server wanting verify uses domain name selector perform dns lookup example given example signature tag gives author domain verified example.net tag selector brisbane string _domainkey fixed part specification gives txt resource record looked codice_6 data returned query record also list tag-value pairs includes domain public key along key usage tokens flags example receiver use public key value p tag validate signature hash value header field check hash value mail message headers body received two values match cryptographically proves mail signed indicated domain tampered transit signature verification failure force rejection message instead precise reasons authenticity message could proven made available downstream upstream processes methods may include sending back fbl message adding authentication-results header field message described rfc 7001 although domainkeys covered yahoo licensed patent claims dual license scheme domainkeys patent license agreement v1.2 gnu general public license v2.0 version essence dkim spf provide different measures email authenticity dmarc provides ability organisation publish policy specify mechanism dkim spf employed sending email domain check field presented end users receiver deal failures reporting mechanism actions performed policies primary advantage system e-mail recipients allowing signing domain reliably identify stream legitimate email thereby allowing domain-based blacklists whitelists effective also likely make certain kinds phishing attacks easier detect incentives mail senders sign outgoing e-mail dkim method labeling message filter identify spam however widespread use dkim prevent spammers forging source address messages technique commonly employ today spammers forced show correct source domain filtering techniques work effectively particular source domain feed reputation system better identify spam conversely dkim make easier identify mail known spam need filtered receiving system whitelist known good sending domains either locally maintained third party certifiers skip filtering signed mail domains perhaps filter remaining mail aggressively dkim useful anti-phishing technology mailers heavily phished domains sign mail show genuine recipients take absence valid signature mail domains indication mail probably forged best way determine set domains merit degree scrutiny remains open question dkim used optional feature called adsp lets authors sign mail self-identify demoted historic status november 2013 instead dmarc used purpose allows domains self-publish techniques including spf dkim employ makes easier receiver make informed decision whether certain mail spam example using dmarc ebay paypal publish policies mail authenticated requesting receiving system gmail reject implemented using dns records added rfc 5322 header field dkim compatible existing e-mail infrastructure particular transparent existing e-mail systems lack dkim support design approach also compatible related services s/mime openpgp content-protection standards dkim compatible dnssec standard spf dkim requires cryptographic checksums generated message sent mail server results computational overhead otherwise required e-mail delivery additional computational overhead hallmark digital postmarks making sending bulk spam computationally expensive facet dkim may look similar hashcash except receiver side verification negligible amount work typical hashcash algorithm would require far work dkim non-repudiation feature prevents senders spammers credibly denying sent email proven useful news media sources wikileaks able leverage dkim body signatures prove leaked emails genuine tampered definitively repudiating claims hillary clinton 2016 us presidential election running mate tim kaine dnc chair donna brazile rfc identifies number potential attack vectors dkim signatures encompass message envelope holds return-path message recipients since dkim attempt protect mis-addressing affect utility number concerns raised refuted 2013 time standardization concern cryptographic solution would message replay abuse bypasses techniques currently limit level abuse larger domains replay inferred using per-message public keys tracking dns queries keys filtering high number queries due e-mail sent large mailing lists malicious queries bad actors comparison different methods also addressing problem see e-mail authentication mentioned authentication abuse prevention evil email user reputable domain compose bad message dkim-signed sent domain mailbox retrieve file obtain signed copy message use l tag signatures makes doctoring messages even easier signed copy forwarded million recipients example botnet without control email provider signed message block offending user stop diffusion already-signed messages validity signatures messages limited always including expiration time tag signatures revoking public key periodically upon notification incident effectiveness scenario hardly limited filtering outgoing mail implies ability detect message might potentially useful spammers dkim currently features two canonicalization algorithms simple relaxed neither mime-aware mail servers legitimately convert different character set often document x-mime-autoconverted header fields addition servers certain circumstances rewrite mime structure thereby altering preamble epilogue entity boundaries breaks dkim signatures plain text messages written us-ascii provided mime header fields signed enjoy robustness end-to-end integrity requires opendkim project organized data collection involving 21 mail servers millions messages 92.3 observed signatures successfully verified success rate drops slightly 90.5 mailing list traffic considered problems might exacerbated filtering relaying software makes changes message without specific precaution implemented sender footer addition operated mailing lists many central antivirus solutions break dkim signature possible mitigation sign designated number bytes message body indicated l tag dkim-signature header anything added beyond specified length message body taken account calculating dkim signature wo n't work mime messages another workaround whitelist known forwarders e.g. spf yet another workaround proposed forwarders verify signature modify email re-sign message sender header however solution risk forwarded third party signed messages received smtp receivers supporting rfc 5617 adsp protocol thus practice receiving server still whitelist known message streams october 2012 wired reported mathematician zach harris detected demonstrated email source spoofing vulnerability short dkim keys codice_7 corporate domain well several high-profile domains stated authentication 384-bit keys factored little 24 hours laptop 512-bit keys 72 hours cloud computing resources harris found many organizations sign email short keys factored notified organizations vulnerability states 768-bit keys could factored access large amounts computing power suggests dkim signing use key lengths greater 1,024 wired stated harris reported google confirmed began using new longer keys soon disclosure according rfc 6376 receiving party must able validate signatures keys ranging 512 bits 2048 bits thus usage keys shorter 512 bits might incompatible shall avoided rfc 6376 also states signers must use keys least 1024 bits long-lived keys though long-livingness specified dkim resulted 2004 merging two similar efforts enhanced domainkeys yahoo identified internet mail cisco merged specification basis series ietf standards-track specifications support documents eventually resulted std 76 currently rfc 6376 identified internet mail proposed cisco signature-based mail authentication standard domainkeys designed yahoo verify dns domain e-mail sender message integrity aspects domainkeys along parts identified internet mail combined create domainkeys identified mail dkim trendsetting providers implementing dkim include yahoo gmail aol fastmail mail organizations carry dkim signature discussions dkim signatures passing indirect mail flows formally dmarc working group took place right first adoptions new protocol wreaked havoc regular mailing list use however none proposed dkim changes passed instead mailing list software changed 2017 another working group launched dkim crypto update dcrup specific restriction review signing techniques rfc 8301 issued january 2018 bans sha-1 updates key sizes 512-2048 1024-4096 rfc 8463 issued september 2018 adds elliptic curve algorithm existing rsa added key type codice_8 adequately strong featuring short public keys easily publishable dns original domainkeys designed mark delany yahoo enhanced comments many others since 2004 specified historic rfc 4870 superseded standards track rfc 4871 domainkeys identified mail dkim signatures published may 2007 number clarifications conceptualizations collected thereafter specified rfc 5672 august 2009 form corrections existing specification september 2011 rfc 6376 merged updated latter two documents preserving substance dkim protocol public key compatibility earlier domainkeys also possible dkim initially produced informal industry consortium submitted enhancement standardization ietf dkim working group chaired barry leiba stephen farrell eric allman sendmail jon callas pgp corporation mark delany miles libbey yahoo jim fenton michael thomas cisco systems attributed primary authors source code development one common library led opendkim project following recent protocol additions licensing new bsd license
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Computer security
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asia-pacific trade agreements database asia-pacific trade investment agreements database aptiad resource researchers policymakers area international trade investment online database allows searches two ways one relates agreements users search agreements members key terms types scopes agreements status another possibility search publications relevant regional integration trade agreements easier use database users download glossary related terms website trade agreements database component aptiad designed give researchers policymakers overview easy access regional bilateral trade agreements entered negotiation countries asia pacific region june 2008 136 agreements including agreements notified wto official information readily available also agreements negotiation least first formal negotiation round interactive trade indicators component aptiad designed help policymakers calculate commonly used indicators related trade performance national economies and/or trade agreements interactive trade indicator database enables select indicators e.g export/import value export/import growth export/import share trade share trade intensity country region product year export flows downloaded un comtrade using world integrated trade solution wits last 10 years present 1998-2007 selected developed developing countries asia-pacific region asia-pacific trade agreements database aptiad product trade investment division united nations economic social commission asia pacific
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Databases
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parlay x parlay x set standard web service apis telephone network fixed mobile defunct replaced oneapi current valid standard gsm association telecom third party api enables software developers use capabilities underlying network apis deliberately high level abstractions designed simple use application developer example invoke single web service request get location mobile device initiate telephone call parlay x web services defined jointly etsi parlay group third generation partnership project 3gpp oma done maintenance specifications 3gpp release 8 apis defined using web service technology interfaces defined using wsdl 1.1 conform web services interoperability ws-i basic profile apis published set specifications general parlay x provides abstraction functionality exposed complex functionally richer parlay apis etsi provide set informative normative parlay x parlay mapping documents parlay x services rolled number telecom operators including bt korea telecom t-com mobilekom sprint
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Web technology
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nms-8250 philips nms-8250 nms short new media systems professional msx 2 home computer high end market two built floppy disk drives pizza box configuration machine fact manufactured sanyo basically mpc-25fs different color featured professional video output possibilities scart better picture quality detachable keyboard
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Computer architecture
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hypertext transfer protocol hypertext transfer protocol http application protocol distributed collaborative hypermedia information systems http foundation data communication world wide web hypertext documents include hyperlinks resources user easily access example mouse click tapping screen web browser development http initiated tim berners-lee cern 1989 development early http requests comments rfcs coordinated effort internet engineering task force ietf world wide web consortium w3c work later moving ietf http/1.1 first documented 1997 specification obsoleted 1999 likewise replaced family rfcs 2014 http/2 efficient expression http semantics wire published 2015 supported major web servers browsers transport layer security tls using application-layer protocol negotiation alpn extension tls 1.2 newer required.. http/3 proposed successor http/2 using udp instead tcp underlying transport protocol like http/2 obsolete previous major versions protocol http functions request–response protocol client–server computing model web browser example may client application running computer hosting website may server client submits http request message server server provides resources html files content performs functions behalf client returns response message client response contains completion status information request may also contain requested content message body web browser example user agent ua types user agent include indexing software used search providers web crawlers voice browsers mobile apps software accesses consumes displays web content http designed permit intermediate network elements improve enable communications clients servers high-traffic websites often benefit web cache servers deliver content behalf upstream servers improve response time web browsers cache previously accessed web resources reuse possible reduce network traffic http proxy servers private network boundaries facilitate communication clients without globally routable address relaying messages external servers http application layer protocol designed within framework internet protocol suite definition presumes underlying reliable transport layer protocol transmission control protocol tcp commonly used however http adapted use unreliable protocols user datagram protocol udp example httpu simple service discovery protocol ssdp http resources identified located network uniform resource locators urls using uniform resource identifiers uri schemes http https example including optional components codice_1 uris encoded hyperlinks html documents form interlinked hypertext documents http/1.1 revision original http http/1.0 http/1.0 separate connection server made every resource request http/1.1 reuse connection multiple times download images scripts stylesheets etc page delivered http/1.1 communications therefore experience less latency establishment tcp connections presents considerable overhead term hypertext coined ted nelson 1965 xanadu project turn inspired vannevar bush 1930s vision microfilm-based information retrieval management memex system described 1945 essay may think tim berners-lee team cern credited inventing original http along html associated technology web server text-based web browser berners-lee first proposed worldwideweb project 1989—now known world wide web first version protocol one method namely get would request page server response server always html page first documented version http http v0.9 1991 dave raggett led http working group http wg 1995 wanted expand protocol extended operations extended negotiation richer meta-information tied security protocol became efficient adding additional methods header fields officially introduced recognized http v1.0 1996 http wg planned publish new standards december 1995 support pre-standard http/1.1 based developing called http-ng rapidly adopted major browser developers early 1996 march year pre-standard http/1.1 supported arena netscape 2.0 netscape navigator gold 2.01 mosaic 2.7 lynx 2.5 internet explorer 2.0 end-user adoption new browsers rapid march 1996 one web hosting company reported 40 browsers use internet http 1.1 compliant web hosting company reported june 1996 65 browsers accessing servers http/1.1 compliant http/1.1 standard defined officially released january 1997 improvements updates http/1.1 standard released june 1999 2007 http working group formed part revise clarify http/1.1 specification june 2014 wg released updated six-part specification obsoleting http/2 published may 2015 http session sequence network request-response transactions http client initiates request establishing transmission control protocol tcp connection particular port server typically port 80 occasionally port 8080 see list tcp udp port numbers http server listening port waits client request message upon receiving request server sends back status line http/1.1 200 ok message body message typically requested resource although error message information may also returned http/0.9 1.0 connection closed single request/response pair http/1.1 keep-alive-mechanism introduced connection could reused one request persistent connections reduce request latency perceptibly client need re-negotiate tcp 3-way-handshake connection first request sent another positive side effect general connection becomes faster time due tcp slow-start-mechanism version 1.1 protocol also made bandwidth optimization improvements http/1.0 example http/1.1 introduced chunked transfer encoding allow content persistent connections streamed rather buffered http pipelining reduces lag time allowing clients send multiple requests waiting response another addition protocol byte serving server transmits portion resource explicitly requested client http stateless protocol stateless protocol require http server retain information status user duration multiple requests however web applications implement states server side sessions using instance http cookies hidden variables within web forms http provides multiple authentication schemes basic access authentication digest access authentication operate via challenge-response mechanism whereby server identifies issues challenge serving requested content http provides general framework access control authentication via extensible set challenge-response authentication schemes used server challenge client request client provide authentication information http authentication specification also provides arbitrary implementation-specific construct dividing resources common given root uri realm value string present combined canonical root uri form protection space component challenge effect allows server define separate authentication scopes one root uri client sends requests server server sends responses request message consists following request line header fields must end cr lf carriage return character followed line feed character empty line must consist cr lf whitespace http/1.1 protocol header fields except host optional request line containing path name accepted servers maintain compatibility http clients http/1.0 specification http defines methods sometimes referred verbs nowhere specification mention verb options head verb indicate desired action performed identified resource resource represents whether pre-existing data data generated dynamically depends implementation server often resource corresponds file output executable residing server http/1.0 specification defined get head post methods http/1.1 specification added five new methods options put delete trace connect specified documents semantics well-known depended client use method server configured support combination methods method unknown intermediate treated unsafe non-idempotent method limit number methods defined allows future methods specified without breaking existing infrastructure example webdav defined 7 new methods specified patch method method names case sensitive contrast http header field names case-insensitive general-purpose http servers required implement least get head methods methods considered optional specification methods example get head options trace convention defined safe means intended information retrieval change state server words side effects beyond relatively harmless effects logging web caching serving banner advertisements incrementing web counter making arbitrary get requests without regard context application state therefore considered safe however mandated standard explicitly acknowledged guaranteed contrast methods post put delete patch intended actions may cause side effects either server external side effects financial transactions transmission email methods therefore usually used conforming web robots web crawlers conform tend make requests without regard context consequences despite prescribed safety get requests practice handling server technically limited way therefore careless deliberate programming cause non-trivial changes server discouraged cause problems web caching search engines automated agents make unintended changes server example website might allow deletion resource url http //example.com/article/1234/delete arbitrarily fetched even using get would simply delete article one example occurring practice short-lived google web accelerator beta prefetched arbitrary urls page user viewing causing records automatically altered deleted en masse beta suspended weeks first release following widespread criticism methods put delete defined idempotent meaning multiple identical requests effect single request methods get head options trace prescribed safe also idempotent http stateless protocol contrast post method necessarily idempotent therefore sending identical post request multiple times may affect state cause side effects financial transactions cases may desirable cases could due accident user realize action result sending another request receive adequate feedback first request successful web browsers may show alert dialog boxes warn users cases reloading page may re-submit post request generally web application handle cases post request submitted note whether method idempotent enforced protocol web server perfectly possible write web application example database insert non-idempotent action triggered get request ignoring recommendation however may result undesirable consequences user agent assumes repeating request safe trace method used part class attacks known cross-site tracing reason common security advice disabled server configuration microsoft iis supports proprietary track method behaves similarly likewise recommended disabled response message consists following status line header fields must end cr lf empty line must consist cr lf whitespace strict requirement cr lf relaxed somewhat within message bodies consistent use system linebreaks cr lf alone http/1.0 since first line http response called status line includes numeric status code 404 textual reason phrase found way user agent handles response depends primarily code secondarily response header fields custom status codes used user agent encounters code recognize use first digit code determine general class response standard reason phrases recommendations replaced local equivalents web developer discretion status code indicated problem user agent might display reason phrase user provide information nature problem standard also allows user agent attempt interpret reason phrase though might unwise since standard explicitly specifies status codes machine-readable reason phrases human-readable http status code primarily divided five groups better explanation request responses client server named popular way establishing encrypted http connection https two methods establishing encrypted http connection also exist secure hypertext transfer protocol using http/1.1 upgrade header specify upgrade tls browser support two however nearly non-existent sample conversation http client http server running www.example.com port 80 client request consisting case request line one header field followed blank line request ends double newline form carriage return followed line feed host field distinguishes various dns names sharing single ip address allowing name-based virtual hosting optional http/1.0 mandatory http/1.1 means /index.html one etag entity tag header field used determine cached version requested resource identical current version resource server content-type specifies internet media type data conveyed http message content-length indicates length bytes http/1.1 webserver publishes ability respond requests certain byte ranges document setting field accept-ranges bytes useful client needs certain portions resource sent server called byte serving connection close sent means web server close tcp connection immediately transfer response header lines optional content-length missing length determined ways chunked transfer encoding uses chunk size 0 mark end content identity encoding without content-length reads content socket closed content-encoding like gzip used compress transmitted data gopher protocol content delivery protocol displaced http early 1990s spdy protocol alternative http developed google superseded new http protocol http/2
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Internet protocols
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national information assurance certification accreditation process national information assurance certification accreditation process niacap formerly minimum-standard process certification accreditation computer telecommunications systems handle u.s. national-security information niacap derived department defense certification accreditation process ditscap played key role national information assurance partnership committee national security systems cnss policy cnssp 22 dated january 2012 cancelled cnss policy 6 “ national policy certification accreditation national security systems ” dated october 2005 national security telecommunications information systems security instruction nstissi 1000 “ national information assurance certification accreditation process niacap ” dated april 2000 cnssp 22 also states cnss intends adopt national institute standards technology nist issuances applicable additional cnss issuances occur needs nss sufficiently addressed nist document annex b identifies guidance documents includes nist special publications sp establishing organization-wide risk management program directs organization make use nist special publication 800-37 implies risk management framework rmf step 5 – authorize information system replaces certification accreditation process national security systems areas federal government fall sp 800-37 rev 1
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Computer security
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john mccarthy computer scientist john mccarthy september 4 1927 – october 24 2011 american computer scientist cognitive scientist mccarthy one founders discipline artificial intelligence coined term artificial intelligence ai developed lisp programming language family significantly influenced design algol programming language popularized timesharing influential early development ai mccarthy spent career stanford university received many accolades honors 1971 turing award contributions topic ai united states national medal science kyoto prize john mccarthy born boston massachusetts september 4 1927 irish immigrant father lithuanian jewish immigrant mother john patrick ida glatt mccarthy family obliged relocate frequently great depression mccarthy father found work organizer amalgamated clothing workers los angeles california father came fishing village cromane county kerry ireland mother died 1957 mccarthy exceptionally intelligent graduated belmont high school two years early mccarthy accepted caltech 1944 mccarthy showed early aptitude mathematics teens taught college mathematics studying textbooks used nearby california institute technology caltech result able skip first two years mathematics caltech mccarthy suspended caltech failure attend physical education courses served us army readmitted receiving b.s mathematics 1948 caltech attended lecture john von neumann inspired future endeavors mccarthy initially completed graduate studies caltech moving princeton university received ph.d. mathematics institution 1951 student solomon lefschetz short-term appointments princeton stanford university mccarthy became assistant professor dartmouth 1955 year later mccarthy moved mit research fellow autumn 1956 1962 mccarthy became full professor stanford remained retirement 2000 end early days mit already affectionately referred uncle john students mccarthy championed mathematical logic artificial intelligence john mccarthy one founding fathers artificial intelligence together alan turing marvin minsky allen newell herbert a. simon mccarthy coined term artificial intelligence 1955 organized famous dartmouth conference summer 1956 conference started ai field minsky later joined mccarthy mit 1959 1958 proposed advice taker inspired later work question-answering logic programming john mccarthy invented lisp late 1950s based lambda calculus lisp soon became programming language choice ai applications publication 1960 1958 mccarthy served acm ad hoc committee languages became part committee designed algol 60 august 1959 proposed use recursion conditional expressions became part algol around 1959 invented so-called garbage collection methods solve problems lisp helped motivate creation project mac mit worked stanford university helped establish stanford ai laboratory many years friendly rival project mac mccarthy instrumental creation three earliest time-sharing systems compatible time-sharing system bbn time-sharing system dartmouth time sharing system colleague lester earnest told los angeles times internet would happened nearly soon except fact john initiated development time-sharing systems keep inventing new names time-sharing came called servers ... call cloud computing still time-sharing john started 1961 perhaps first suggest publicly idea utility computing speech given celebrate mit centennial computer time-sharing technology might result future computing power even specific applications could sold utility business model like water electricity idea computer information utility popular late 1960s faded mid-1990s however since 2000 idea resurfaced new forms see application service provider grid computing cloud computing 1966 mccarthy team stanford wrote computer program used play series chess games counterparts soviet union mccarthy team lost two games drew two games see kotok-mccarthy 1978 1986 mccarthy developed circumscription method non-monotonic reasoning 1982 seems originated idea space fountain type tower extending space kept vertical outward force stream pellets propelled earth along sort conveyor belt returns pellets earth payloads would ride conveyor belt upward mccarthy often commented world affairs usenet forums ideas found sustainability web page aimed showing human material progress desirable sustainable mccarthy serious book reader optimist staunch supporter free speech best usenet interaction visible rec.arts.books archives john actively attended sf bay area dinners palo alto r.a.b readers called rab-fests john went defend free speech criticism involving european ethnic jokes stanford mccarthy saw importance mathematics mathematics education usenet .sig years refuses arithmetic doomed talk nonsense license plate cover read similarly arithmetic doomed talk nonsense advised 30 phd graduates 2001 short story robot baby farcically explored question whether robots simulate emotions anticipated aspects internet culture social networking become increasingly prominent ensuing decades mccarthy married three times second wife vera watson programmer mountaineer died 1978 attempting scale annapurna part all-women expedition organised arlene blum later married carolyn talcott computer scientist stanford later sri international mccarthy considered atheist raised communist became conservative republican two-day visit czechoslovakia 1968 soviet invasion mccarthy died home stanford october 24 2011 1979 mccarthy wrote article entitled ascribing mental qualities machines wrote machines simple thermostats said beliefs beliefs seems characteristic machines capable problem-solving performance 1980 philosopher john searle responded famous chinese room argument disagreeing mccarthy taking stance machines beliefs simply conscious searle argues machines lack understanding intentionality term commonly used philosophy mind vast amount literature written support one side
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Programming language topics
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amir pnueli amir pnueli april 22 1941 – november 2 2009 israeli computer scientist 1996 turing award recipient pnueli born nahalal british mandate palestine israel received bachelor degree mathematics technion haifa ph.d. applied mathematics weizmann institute science thesis topic calculation tides ocean switched computer science stint post-doctoral fellow stanford university works computer science focused temporal logic model checking particularly regarding fairness properties concurrent systems returned israel researcher founder first chair computer science department tel aviv university became professor computer science weizmann institute 1981 1999 death pnueli also held position computer science department new york university new york u.s.. pnueli also founded two startup technology companies career three children death four grandchildren pnueli died november 2 2009 brain hemorrhage
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Programming language topics
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cryptmount cryptmount software tool managing encrypted file systems linux family operating systems uses device mapper dm-crypt infrastructure provide transparent encryption file systems stored disk partitions within ordinary files main features codice_1 include
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Computer file systems
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infrastructure code infrastructure code iac process managing provisioning computer data centers machine-readable definition files rather physical hardware configuration interactive configuration tools infrastructure managed comprises physical equipment bare-metal servers well virtual machines associated configuration resources definitions may version control system use either scripts declarative definitions rather manual processes term often used promote declarative approaches iac approaches promoted cloud computing sometimes marketed infrastructure service iaas iac supports iaas confused iac grew response difficulty posed two pieces technology – utility computing second-generation web frameworks 2006 launch amazon web services ’ elastic compute cloud 1.0 version ruby rails months brought widespread scaling problems many enterprises problems previously witnessed huge companies new tools emerging handle ever growing field idea iac born thought modelling infrastructure code ability design implement deploy applications infrastructure known software best practices appealed software developers infrastructure administrators ability treat like code use tools software project would allow developers rapidly deploy applications value iac broken three measurable categories cost reduction speed faster execution risk remove errors security violations cost reduction aims helping enterprise financially also terms people effort meaning removing manual component people able refocus efforts towards enterprise tasks infrastructure automation enables speed faster execution configuring infrastructure aims providing visibility help teams across enterprise work quickly efficiently automation removes risk associated human error like manual misconfiguration removing decrease downtime increase reliability outcomes attributes help enterprise move towards implementing culture devops combined working development operations generally three approaches iac declarative functional vs. imperative procedural vs. intelligent environment aware difference declarative imperative intelligent approach essentially 'what versus 'how versus 'why declarative approach focuses eventual target configuration imperative focuses infrastructure changed meet intelligent approach focuses configuration certain way consideration co-relationships co-dependencies multiple applications running infrastructure typically found production declarative approach defines desired state system executes needs happen achieve desired state imperative defines specific commands need executed appropriate order end desired conclusion intelligent determines correct desired state system executes needs happen achieve desired state impact co-dependent applications environment aware desired state next generation iac two methods iac 'push 'pull main difference manner servers told configured pull method server configured pull configuration controlling server push method controlling server pushes configuration destination system many tools fulfill infrastructure automation capabilities use iac broadly speaking framework tool performs changes configures infrastructure declaratively imperatively based programmatic approach considered iac traditionally server lifecycle automation configuration management tools used accomplish iac enterprises also using continuous configuration automation tools stand-alone iac frameworks microsoft ’ powershell dsc aws cloudformation continuous configuration automation cca tools thought extension traditional iac frameworks leverage iac change configure automate infrastructure also provide visibility efficiency flexibility infrastructure managed additional attributes provide enterprise-level security compliance making companies keen implementing types tools important aspect considering cca tools open source community content gartner states value cca tools “ dependent user-community-contributed content support commercial maturity performance automation tooling. ” vendors like puppet chef around significant amount time created communities chef chef community repository puppet puppetforge vendors rely adjacent communities leverage iac frameworks powershell dsc new vendors emerging content driven model driven intelligence product deliver content visual object-oriented systems work well developers especially useful production oriented devops operations constituents value models versus scripting content field continues develop change community based content become ever important iac tools used unless model driven object oriented notable cca tools include iac key attribute enabling best practices devops – developers become involved defining configuration ops teams get involved earlier development process tools utilize iac bring visibility state configuration servers ultimately provide visibility users within enterprise aiming bring teams together maximize efforts automation general aims take confusion error-prone aspect manual processes make efficient productive allowing better software applications created flexibility less downtime overall cost effective way company iac intended reduce complexity kills efficiency manual configuration automation collaboration considered central points devops infrastructure automation tools often included components devops toolchain
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Distributed computing architecture
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cpu shielding cpu shielding practice multiprocessor system cpu multiple cores real-time tasks run one cpu core non-real-time tasks run another operating system must able set cpu affinity processes interrupts linux order shield cpus individual interrupts serviced make sure following kernel configuration parameter set
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Operating systems
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dominic giampaolo dominic p. giampaolo software developer helped develop file system operating system beos currently works apple inc. graduating lewiston high school lewiston maine 1987 started studying political science american university washington dc changed computer science one semester completing bachelor degree master degree worcester polytechnic institute graduating travelled west coast work silicon graphics advanced systems division worked group ported irix 64-bit r8000 microprocessor chip set worked realityengine infinitereality graphics systems working silicon graphics located fixed bug discreet logic flame compositing system delaying post-production motion picture speed october 1995 giampaolo heard bebox friend poker game shortly visiting inc. offices see demo computer began working beos working initially number areas including kernel posix layer notably developing file system alongside cyril meurillon replaced old file system written benoit schillings replaced original flat file system written meurillon file system included number advances compared personal computer filesystems use time journal improve reliability support extensive metadata indexed respond quickly searches giampaolo worked google qnx software systems qnx discovered bug instruction fetch unit intel pentium ii pentium iii processors since march 2002 giampaolo working apple inc. part mac os x file system apple file system project spotlight groups
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Operating systems
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socket 5 socket 5 created second generation intel p5 pentium processors operating speeds 75 120 mhz well certain pentium overdrive pentium mmx processors core voltage 3.3 v. superseded earlier socket 4 released march 1994 consisting 320 pins first socket use staggered pin grid array spga allowed chip pins spaced closer together earlier sockets socket 5 replaced socket 7 1997
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Computer architecture
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information exchange gateway nato defined concept information exchange gateway ieg facilitate secure communication different security management domains ieg designed provide standard secure method communication nato nato nations non-nato nations coalition forces non government organisations ngos international organisations ios information exchange gateway provides information exchange services ies facilitate exchange information networks including data protocol translation necessary information protection services ips ensure intended information exchanged addition node protection services nps ensure information exchanged safe secure way intended information validated ips exchanged nato defined five main ieg scenarios scenario variants transferring classified information scenarios take account security classifications domains connect well security policy owners administrators domains scenarios ieg must include guard provide ips nps functions used guard ieg dmz split two
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Computer security
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macintosh se/30 macintosh se/30 personal computer designed manufactured sold apple computer inc. january 1989 october 1991 fastest original black-and-white compact macintosh series se/30 black-and-white monitor single pds slot rather nubus slots iix se/30 shares common architecture supported third-party accelerators network cards display adapter although officially able support 32 mb se/30 could expand 128 mb ram significant amount ram time included 40 80 mb hard drive also first compact mac include 1.44 mb high density floppy disk drive standard late versions se one earlier versions power se/30 demonstrated use produce week newspaper first colour tabloid newspaper uk use new digital pre-press technology personal desktop computer keeping apple practice apple ii+ power macintosh g3 announced logic board upgrade available convert regular se se/30 se would exactly specs se/30 difference floppy drive se 800 kb drive set included new front bezel replace original se bezel se/30 naming scheme used time apple indicated presence 68030 processor adding letter x model name macintosh se upgraded 68030 processor posed awkward problem apple willing name new computer macintosh sex thus se/30 name chosen internally code names green jade fafnir roadrunner used machine followed 1991 macintosh classic ii despite processor clock speed 60 fast se/30 due 16-bit data path supported 10 mb memory lacked internal expansion slot made motorola 68882 fpu optional upgrade although uses 32-bit instructions se/30 rom like iix rom includes code using 24-bit addressing rendering rom 32-bit dirty limited actual amount ram accessed 8 mb system 6.0.8 system extension called mode32 enables access installed extra memory system 6.0.8 system 7.0 system 7.5.5 se/30 use 128 mb ram alternatively replacing rom simm one mac iisi mac iifx makes se/30 32-bit-clean thereby enables use 128 mb ram system 7.5 os 8.1 standard se/30 run system 7.5.5 since mac os 7.6 requires 32-bit-clean rom additionally se/30 run a/ux apple older version unix able run macintosh programs though official upgrade path se/30 several third-party processor upgrades available 68040 upgrade made possible run mac os 8.1 extended se/30 productive life many years micron technology xceed gray-scale 30 video card fit se/30 pds slot enabling display greyscale video internal display non-color compact mac able bruce f. webster wrote macworld march 1989 se/30 break new ground however establish apple commitment classic mac product line provides users apple-supported alternative either small slow mac large powerful one important fills gap macintosh family ... new level power portability macintosh community january 2009 macworld feature commemorating 25th anniversary macintosh three industry commentators – adam c. engst tidbits john gruber daring fireball john siracusa ars technica – chose se/30 favorite mac model time like great mac wrote gruber se/30 n't terrific system debuted remained eminently usable years come think original mac era machine mind se/30 se/30 remains popular hobbyists described “ best computer apple ever make ” used models selling significant premium machines era contemporary pds upgrades allowed se/30 ’ internal monitor upgraded support 256 shades gray original-design macintosh support upgrade 68040 processor se/30 ’ standard ram limit 128mb greatly exceeded even much later models color classic macintosh lc ii 2018 add-ons software became available add wifi even streaming spotify support se/30 nbc tv series seinfeld jerry se/30 sitting desk first seasons would first many macs occupy desk including powerbook duo twentieth anniversary macintosh fx series always sunny philadelphia waitress seen macintosh se/30 bedroom desk episode gang gives back film watchmen ozymandias all-black tempest-shielded se/30 desk film peter parker shown macintosh se/30 bedroom
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Computer architecture
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tsp econometrics software tsp programming language estimation simulation econometric models tsp stands time series processor although also commonly used cross section panel data program initially developed robert hall graduate studies massachusetts institute technology 1960s company behind program tsp international founded 1978 bronwyn h. hall robert hall wife divorce april 1983 asset tsp split two versions subsequently two versions diverged terms interface types subroutines included one version tsp still developed tsp international version initially named microtsp named eviews developed quantitative micro software
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Programming language topics
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access grid access grid collection resources technologies enables large format audio video based collaboration groups people different locations access grid ensemble resources including multimedia large-format displays presentation interactive environments interfaces grid computing middleware visualization environments simple terms advanced videoconferencing using big displays multiple simultaneous camera feeds node site technology invented argonne national laboratory chicago alliance chautauqua 99 series two-day conferences computational science organised ncsa first large-scale access grid event access grid later demonstrated supercomputing'99 portland international audience latest stable version software release 3.2 also installable bundle additional video codecs hd additional tools access grid generated great interest activity australia factors widely disparate geographic locations relatively low population-densities previously presented great obstacles in-person collaborations international centre excellence education mathematics ice-em funded 10 australian universities construct nodes nodes allow mathematics postgraduate community professionals access international experts visiting australia nodes also provide means carrying collaborative research peers within australia internationally australia first access grid node built sydney vislab australian technology park august 2001 2007 australian ag network grown 30 sites serviced asia pacific access grid apag venue servers university sydney ag2 university queensland ag3 university queensland began providing ag facilities 2002 increasing usage every year since 2004 uq vislab began providing access grid installation packages various linux distributions well freebsd wider ag community although intellectual property concerns placed future linux-based technologies doubt also active developing various enhancements add-ons including shared applications remote sensor monitoring shared application remote thermo shared gis based grass december 2006 new zealand university operational ag node use grid increasing current development work includes federated data management using storage resource broker srb high definition video communications uk academic community support access grid toolkit iocom evo technologies janet provided janet videoconferencing management centre first access grid ag node built university manchester 2001 jisc-funded support access grid support centre agsc manchester april 2004 july 2011 three hundred ag nodes registered uk ranging full room nodes small individual desktop nodes number academic projects using ag technologies taught course centre magic postgraduate mathematics mathematics projects
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Distributed computing architecture
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macintosh iici macintosh iici personal computer designed manufactured sold apple computer inc. september 1989 february 1993 powerful version macintosh iicx released earlier year shares compact case design three expansion slots iici improved upon iicx 16 mhz motorola 68030 cpu 68882 fpu replacing 25 mhz versions chips macintosh quadra 700 introduced end 1991 apple mainstream workstation product replace iici albeit significantly higher price point time apple authorized resellers offering entry-level iici systems 4,000 usd less whereas quadra 700 entered market 6,000 usd apple continued sell iici early 1993 less expensive quadra 650 comparably-priced quadra 800 introduced iici introduced several technical architectural enhancements important preparing system 7 called blue project would influence future macintoshes though came cost compatibility iici one popular longest-lived macintosh models 20th century much lifespan business workhorse macintosh line short time 1989 introduction 40 mhz macintosh iifx iici fastest mac available iici came either 40- 80-megabyte hard disk possible upgrades include 25 33 40 50 mhz daystar 68030 boards quadra 700 motherboard couple different third-party 68040 upgrades two powerpc 601 upgrade cards running either 66 mhz 100 mhz exclusively daystar digital bought xlr8 still holds daystar product logo name line products 68030 68040 upgrades also made sonnet diimo companies quadra 700 released 1991 logic board upgrade made available iici upgrade performance level quadra easter egg exists iici rom system date set september 20 1989 machine release date keys held boot time image development team displayed signatures product design team seen molded plastic case one removes motherboard
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Computer architecture
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in-memory processing computer science in-memory processing emerging technology processing data stored in-memory database older systems based disk storage relational databases using sql query language increasingly regarded inadequate meet business intelligence bi needs stored data accessed much quickly placed random-access memory ram flash memory in-memory processing allows data analysed real time enabling faster reporting decision-making business hitherto prevalent disk-based technology data loaded computer hard disk form multiple tables multi-dimensional structures queries run disk-based technologies relational database management systems rdms often based structured query language sql sql server mysql oracle many others rdms designed requirements transactional processing using database supports insertions updates well performing aggregations joins typical bi solutions typically slow another drawback sql designed efficiently fetch rows data bi queries usually involve fetching partial rows data involving heavy calculations improve query performance multidimensional databases olap cubes also called multidimensional online analytical processing molap constructed designing cube elaborate lengthy process changing cube structure adapt dynamically changing business needs may cumbersome cubes pre-populated data answer specific queries although increase performance still suitable answering ad-hoc queries information technology staff spend substantial development time optimizing databases constructing indexes aggregates designing cubes star schemas data modeling query analysis reading data hard disk much slower possibly hundreds times compared reading data ram especially analyzing large volumes data performance severely degraded though sql powerful tool complex queries take relatively long time execute often result bringing performance transactional processing order obtain results within acceptable response time many data warehouses designed pre-calculate summaries answer specific queries optimized aggregation algorithms needed increase performance memory processing accomplished via traditional databases oracle db2 microsoft sql server via nosql offerings in-memory data grid like hazelcast infinispan oracle coherence scaleout software in-memory database data grid information initially loaded memory ram flash memory instead hard disks data grid processing occurs three order magnitude faster relational databases advanced functionality acid degrade performance compensation additional functionality arrival column centric databases store similar information together allow data stored efficiently greater compression ratios allows huge amounts data stored physical space reducing amount memory needed perform query increasing processing speed many users software vendors integrated flash memory systems allow systems scale larger data sets economically oracle integrating flash memory oracle exadata products increased performance microsoft sql server 2012 bi/data warehousing software coupled violin memory flash memory arrays enable in-memory processing data sets greater 20tb users query data loaded system ’ memory thereby avoiding slower database access performance bottlenecks differs caching widely used method speed query performance caches subsets specific pre-defined organized data in-memory tools data available analysis large data mart small data warehouse entirely memory accessed quickly multiple concurrent users applications detailed level offers potential enhanced analytics scaling increasing speed application theoretically improvement data access speed 10,000 1,000,000 times compared disk also minimizes need performance tuning staff provides faster service end users certain developments computer technology business needs tended increase relative advantages in-memory technology range in-memory products provide ability connect existing data sources access visually rich interactive dashboards allows business analysts end users create custom reports queries without much training expertise easy navigation ability modify queries fly benefit many users since dashboards populated fresh data users access real time data create reports within minutes in-memory processing may particular benefit call centers warehouse management in-memory processing source database queried instead accessing database every time query run thereby eliminating repetitive processing reducing burden database servers scheduling populate in-memory database overnight database servers used operational purposes peak hours large number users large amount ram needed in-memory configuration turn affects hardware costs investment likely suitable situations speed query response high priority significant growth data volume increase demand reporting facilities may still cost-effective information subject rapid change security another consideration in-memory tools expose huge amounts data end users makers advise ensuring authorized users given access data
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Databases
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ms-dos 5 beta ms-dos 5.0 project started december 1989 ms-dos 5.0 codename lifeboat based ms-dos 4.00 code ms-dos 5.00 first version ms-dos use betas builds several ms-dos 5.00 betas released final launch
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Operating systems
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cyber-arms industry cyber-arms industry markets associated events surrounding sale software exploits zero-days cyberweaponry surveillance technologies related tools term may extend grey black markets online offline many years burgeoning dark web market remained niche available in-the-know well funded since least 2005 western governments including u.s. united kingdom russia france israel buying exploits defence contractors individual hackers 'legitimate market zero day exploits exists well advertised immediately accessible attempts openly sell zero day exploits governments security vendors keep black market far unsuccessful traditional arms producers military services companies bae systems eads leonardo general dynamics raytheon thales expanded cybersecurity markets however smaller software companies blue coat amesys also become involved often drawing attention providing surveillance censorship technologies regimes bashar al-assad syria muammar gaddafi libya suppliers exploits western governments include massachusetts firm netragard trade show iss world runs every months referred 'international cyber arms bazaar 'wiretappers ball focuses surveillance software lawful interception popular internet forums generally russian ukrainian reports english-only chinese-only german-only vietnamese-only sites among others phishing spear-phishing social engineer campaigns typically done english majority potential victims know language india central bureau investigation describe proliferation underground markets 'widespread colonel john adams head marine corps intelligence activity expressed concerns markets could allow cyberweapony fall hands hostile governments would otherwise lack expertise attack advanced country computer systems online increasing uses encryption privacy mechanisms record messaging cryptocurrencies since 2005 darknet markets black markets 'cyber arms bazaar prices dropping fast cost cyberweapony plummeting least 90 percent botnets increasingly rented cyber criminals commodities variety purposes rdp shops offer cheap access hacked computers recent years many software firms success bug bounty programs cases vupen chrome exploit rejected market value meanwhile vendors hp spent 7 million 2005 2015 buying exploits software behaviour criticised head united states cyber command general keith alexander building black market
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Computer security
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firehol firehol shell script designed wrapper iptables written ease customization linux kernel firewall netfilter firehol graphical user interface configured easy understand plain text configuration file advantage firehol friendliness beginners n't worry answer packet firehol first parses configuration file sets appropriate iptables rules achieve expected firewall behavior large complex bash script file depending iptables console tools rather communicating kernel directly advantage portability linux system iptables bash appropriate tools run main drawback slower starting times particularly older systems since delay happens per boot—or less resulting rules saved disk—high performance generally important except embedded systems firehol also benefits shell flexibility easily extended configured high degree firehol configuration files fully functional bash scripts one write scripts normal shell syntax operate expected one might loop firehol statement forward entire set ports example firehol free software open-source distributed terms gnu general public license
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Computer security
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ntfsprogs ntfsprogs collection free unix utilities managing ntfs filesystem used windows nt operating system since version 3.1 hard disk partition 'ntfsprogs first stable method writing ntfs partitions linux ntfs versions supported used 32-bit 64-bit windows ntfsprogs remains popular way interacting ntfs partitions included linux distributions live cds also versions compiled windows april 12 2011 tuxera announced ntfsprogs project merged ntfs-3g programs included basic functionality and/or intended developers
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Computer file systems
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surface 2012 tablet first-generation surface launched surface windows rt later marketed surface rt hybrid tablet computer developed manufactured microsoft announced june 18 2012 released october 26 2012 first ever personal computer designed in-house microsoft positioned direct competitor apple ipad line surface included several notable features including folding kickstand allowed tablet stand angle ability attach optional protective covers incorporated keyboards surface served launch device windows rt variation windows 8 designed devices based arm architecture windows rt contains notable differences limitations compared windows 8 including several removed features bundled special edition microsoft office 2013 home student besides software included operating system incompatible desktop software runs windows 8 personal computers tablets intel compatible processors windows rt run metro-style apps obtained windows store however visually resembling surface pro 2-in-1 detachable surface considered 2-in-1 pc fact variant hybrid tablet surface met mixed reviews although praised hardware design accessories aspects operating system criticism directed towards performance device well limitations windows rt operating system application ecosystem sales surface poor microsoft cutting price worldwide taking us 990 million loss july 2013 result succeeded surface 2 2013 comes newer rt 8.1 os original surface also since received update support surface 2 end 2023 device announced press-only event los angeles first pc microsoft designed manufactured in-house surface supports wifi wireless connectivity cellular variant tablet went sale eight countries australia canada china france germany hong kong united kingdom united states surface pro launched later surface tablet display 1366x768 pixels five-point multi-touch touchscreen gorilla glass 2 device measures made magnesium kickstand usb port magnetic keyboard interface give surface ability add wireless mouse external keyboard thumb drive also slot microsd card add 200 gb surface runs windows rt preloaded windows mail calendar contacts sports news travel finance camera weather reader skydrive store photos skype longer supported maps games messaging bing desktop xbox music xbox video windows store applications supports microsoft office home student 2013 rt includes word powerpoint excel onenote within desktop application windows rt allows installing windows store applications windows rt compiled entirely arm instruction set architecture major update windows rt 8.0 launched october 17 2013 called windows rt 8.1 update brought many improvements surface overhauled mail app bing apps like reading list onedrive updated skydrive also brought support larger tiles help tips app internet explorer 11 outlook 2013 rt changes pc settings lockscreen photo slideshow infinitely re-sizable apps start button speed improvements later update windows rt 8.1 dubbed windows rt 8.1 update added search button start screen well taskbar modern ui title bar modern ui apps surface launched two accessories type cover touch cover touch cover came white black magenta red cyan type cover came black limited edition touch covers released featuring laser-etched artwork back touch type covers double keyboards magnetically attach surface accessory spine later adapters micro-hdmi hdmi vga released cnet praised design surface noting looked practical without cold feels like high-quality device microsoft cut corners make kickstand also praised feel quality kickstand keyboard cover accessories also noted satisfying clicking sound engaged attached covers deemed essential getting complete surface experience touch cover praised spacious typing area tablet keyboard attachments usable getting used soft feel type cover recommended touch cover due higher quality conventional key design surface display praised larger size widescreen aspect ratio ipad line panned muted color reproduction touchscreen-oriented aspects windows 8 interface praised elegant albeit harder learn android ios windows rt operating system panned still requiring use mouse-oriented desktop interface access applications settings accessible within metro shell poor application ecosystem windows store state on-launch compared ghost town apocalypse surface also panned poor performance especially comparison tegra 3-based tablets conclusion felt paired keyboard cover surface excellent office productivity tool best tablet form entertainment needs n't go far beyond movies tv shows music occasional simple game 're covered well assuming windows store would eventually improve application selection surface wonky performance keep useful productivity device reaching true tablet greatness sales surface windows rt devices poor july 2013 microsoft reported loss us 900 million due lackluster sales surface cut price 30 worldwide microsoft price cut result slight increase market share device late-august 2013 usage data advertising network adduplex provides advertising services within windows store apps revealed surface share increased 6.2 9.8
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Operating systems
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shared-nothing architecture shared-nothing architecture sn distributed-computing architecture update request satisfied single node processor/memory/storage unit intent eliminate contention among nodes nodes share independently access memory storage one alternative architecture shared everything requests satisfied arbitrary combinations nodes may introduce contention multiple nodes may seek update data time sn eliminates single points failure allowing overall system continue operating despite failures individual nodes allowing individual nodes upgrade without system-wide shutdown sn system scale simply adding nodes since central resource bottlenecks system another term sn sharding sn system typically partitions data among many nodes refinement replicate commonly used infrequently modified data across many nodes allowing requests resolved single node michael stonebraker university california berkeley used term 1986 database paper teradata delivered first sn database system 1983 tandem computers released nonstop sql shared nothing database 1984 shared-nothing popular web development shared-nothing architectures prevalent data warehousing applications although requests require data multiple nodes dramatically reduce throughput
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Distributed computing architecture
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zanac released msx computer family computer disk system nintendo entertainment system virtual console reworked msx2 computer zanac ex playstation zanac x zanac players fly lone starfighter dubbed afx-6502 zanac twelve levels goal destroy system —a part-organic part-mechanical entity bent destroying mankind zanac developed main core developers compile including masamitsu moo niitani koji janus teramoto takayuki jemini hirono developers went make popular similarly-based games guardian legend blazing lazers puyo puyo series game known intense fast-paced gameplay level difficulty music seems match pace game praised unique adaptive artificial intelligence game automatically adjusts difficulty level according player skill level rate fire ship current defensive status/capability zanac player controls spaceship afx-6502 zanac flies various planets space stations outer space armada enemies comprising defenses game main antagonist—the system player must fight twelve levels destroy system defenses objective shoot enemies projectiles accumulate points players start three lives lose life get hit enemy projectile losing life gameplay continues player reappearing screen losing previously accumulated power-ups player remains temporarily invincible moment upon reappearing screen game ends player lives lost completing twelfth final area however player earn 1-ups extra lives throughout game accumulating high point scores zanac continue option allows players restart game level lost lives player operates rapid-fire main cannon upgraded collecting power-ups found blue boxes periodically descend top screen main cannon power level upgraded number bullets fired ship well speed increases addition player operates specialty weapon separate main cannon eight different specialty weapons represented differently-numbered power-ups player change type specialty weapon equipped collecting differently-numbered power-up upgrade current specialty weapon collecting numbered power-up matches current weapon weapons range directional bullets shields indestructible projectiles players lose accumulated power-ups lose life enemies zanac include meteors various bullet-shooting enemy aircraft bullet-resistant disks ground turrets reconnaissance planes bosses consist stationary fortresses consisting entirely ground turrets player must destroy turrets within specified time limit score bonus points every stage one stationary fortresses addition large enemy ships acting mini-bosses appear throughout game ships resistant player weaponry bullets inflict minor damage repelled mini-bosses change color become damaged distinguishing aspect zanac gameplay unique enemy artificial intelligence called automatic level difficulty control alc alc measures system aggressiveness game difficulty depending actions player attack pattern skill level alc increases experts decreases inexperienced players instance shooting main cannon frequently collecting power-ups failing destroy bosses within specified time limit increases alc resulting greater number tougher enemies appearing screen however actions losing lives starting new level destroying reconnaissance planes reduces alc resulting fewer on-screen enemies plot zanac revolves around system —a device figuratively similar pandora box system created millennia ago unknown alien race contains boundless wisdom knowledge well vast destructive potential properly opened would grant access untold wisdom technology improperly accessed would unleash almost unlimited destruction mankind attempted access system failed causing system spread throughout space exert mass destruction forms life including human race mankind discovered properly access knowledge technology within system could shut destructive expansion vast tactical systems moreover defenses system designed around destroying overcoming entire fleets mankind hopes lone starfighter may able slip penetrate defenses system allowing ship fight way heart system destroy afx-6502 zanac advanced starfighter ever produced launched desperate mission fight way heart system shut zanac initially released 1986 msx computer japanese video game company compile—the company responsible games blazing lazers devil crush puyo puyo series compile re-released game msx2 computer later year zanac ex featured improved graphics sound original msx version zanac ported heavily reworked release family computer disk system japan north america nes october 1987 nes version later re-released wii virtual console service published d4 enterprise version identical nes version released 1987 compile released compilation titled zanac x zanac sony playstation console japan commemorate 15th anniversary original compilation features updated version zanac —titled zanac neo —and three versions nes version game including version featuring enhanced graphics sound game features two-player cooperative gameplay well remix game soundtrack zanac retrospect considered unique shoot 'em game combining gameplay elements games xevious especially extensive power-up system vertical-scrolling gameplay features air ground targets brett alan weiss allgame praised zanac calling extremely fast-paced shooter player almost completely surrounded enemy ships bullets praises game music seems flow along action game calls music least close get zen moment playing shooting game nes frank provo gamespot lauded zanac difficulty level ability handle many sprites screen without slowdown glitches unique ai placed game subgenre however criticisms include mediocre primitive music sound steep learning curve gameplay difficulty level poor translation game game instruction manual addition weiss says enemies zanac fearsome n't much personality
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Computer architecture
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case preservation computer file system stores file names computer may keep discard case information case stored called case preservation system case-preserving necessarily case-insensitive possible common system case-insensitive yet case-preserving combination often considered natural people understand people prefer using correct capitalization still recognize others example someone refers united states america understood mean united states america even though capitalization incorrect versions macos prior introduction apfs current versions microsoft windows operating systems versions amiga os case-preserving case-insensitive cases since case-insensitive requesting file name capitalization used contrast case-sensitive systems single capitalization would work case-preserving viewing file name presented capitalization used file created non-case-preserving system arbitrary capitalization would displayed instead upper- lower-case also case-insensitive case preserving file systems readme.txt readme.txt folder examples systems various case-sensitivity case-preservation exist among file systems
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Computer file systems
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security technical implementation guide security technical implementation guide stig cybersecurity methodology standardizing security protocols within networks servers computers logical designs enhance overall security guides implemented enhance security software hardware physical logical architectures reduce vulnerabilities examples stigs would benefit configuration desktop computer enterprise server operating systems inherently secure leaves open criminals identity thieves computer hackers stig describes minimize network-based attacks prevent system access attacker interfacing system either physically machine network stigs also describe maintenance processes software updates vulnerability patching advanced stigs might cover design corporate network covering configurations routers firewalls domain name servers switches
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Computer security
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hercules processors hercules line arm architecture-based microcontrollers texas instruments built around one arm cortex cores hercules safety microcontroller platform includes series microcontrollers specifically targeted functional safety applications hardware-base fault correction/detection features dual cores run lock-step full path ecc automated self testing memory logic peripheral redundancy monitor/checker cores line includes tms470m tms570 rm4 families families designed specifically iec 61508 iso 26262 safety critical applications however differ significantly degree support safety standards
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Computer architecture
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lively kernel lively kernel open-source web programming environment supports desktop-style applications rich graphics direct manipulation abilities without installation upgrade troubles conventional desktop applications development began sun microsystems laboratories menlo park california later moved hasso plattner institute potsdam-babelsberg near berlin lively kernel graphical composition integrated programming environment written fully programming language javascript using standard browser graphics w3c canvas svg thus accessible browser web page begins operating soon web page loaded able edit code graphics built-in webdav support save results even clone onto new web pages along application development abilities also function integrated development environment ide making whole system self-sufficient tools except browser lively kernel uses morphic graphics model add behavior scene graph built browser graphics simple graphics thus assembled standard widgets sliders scroll bars text views lists clipping frames simple window system built widgets offers object inspectors file browsers code browsers even rudimentary demo pages thus ability edit test new code simple code browser system running lively used build simple web sites including tutorial also client-side wiki system stores pages versioned repository content vary relatively static pages text fully dynamic models look behave like adobe flash simulations lively kernel achieves complex dynamic behavior without specific animation support use animation features svg simple scheduling multiple green-thread processes javascript lively kernel includes multifont text editor written javascript includes support centering justification similar rudimentary text composition abilities working lively thus much feel working web page design program except on-the-fly text layout done offline composition program built-in dynamic behavior text lively kernel liveliness lively graphics becomes even apparent manipulating scale rotation handles objects text whole code browser used tilted 20 degrees side text editor made entirely lively graphics works perfectly well rotated scaled scroll bars clipping frames rest entire user interface lively kernel depends browser support javascript svg canvas graphics part w3c standards 2009 means runs safari firefox chrome opera browsers requirement might seem less compatible html lively actually compatible across browsers runs html uniformity among javascript svg canvas implementations one html implementation another except one small initial file lively kernel code base entirely free tests client browser used 2011 lively kernel runs best webkit-based browsers safari macintosh chromium google chrome windows running internet explorer windows requires google chrome frame testing popular browsers planned next release lively includes integrated development environment considerable power designed work via webdav local set dozen source javascript files synchronizable versioned repository user opens systembrowser javascript source files listed file pane browser user clicks one files read parsed ometa javascript parser displayed similar smalltalk browser functions class definitions listed class method names shown user click method name edit code bottom pane save new definition new definition checked syntax correct stored back .js file moreover eval mode usual case method redefined system running allows non-critical changes made without need restart lively applications developed source files loaded rapid scan find every reference selected text present code bodies match separate sub-browser lively ide includes object inspectors morph style panels controlling fills borders text styles also facilities debugging error points profiling performance tuning pushed owing improving quality run-time support major browsers ide operates source code files versioned repository manage evolution lively code base approach used empower users control active web content form client-side wiki lively includes facilities edit content worlds scene graphs content store content web pages webdav connection allows lively store new versions page content incrementally developed new version saved viewable rest internet prior versions retrieved cases error change mind notable wiki style evolving web content extends textual graphical scripting content lively well new forms may defined yet without need wiki server kind required server providing http webdav interface increasing amounts lively project content maintained manner lively qt new implementation lively kernel kernel parts replaced functionality offered qt framework lively qt inherits basic functionality implementation widgets layout management core event handling core javascript support qt lively qt retains exceptionally interactive nature liveliness lively kernel e.g. allowing user interface application source code edited fly however lively qt development work performed using familiar well-documented apis qt platform
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Programming language topics
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logic error computer programming logic error bug program causes operate incorrectly terminate abnormally crash logic error produces unintended undesired output behaviour although may immediately recognized logic errors occur compiled interpreted languages unlike program syntax error program logic error valid program language though behave intended often clue existence logic errors production wrong solutions though static analysis may sometimes spot one ways find type error output program variables file screen order determine error location code although work cases example calling wrong subroutine easiest way find problem program uses incorrect results bad mathematical calculation example function c calculate average two numbers contains logic error missing parentheses calculation compiles runs give expected answer due operator precedence division evaluated addition
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Programming language topics
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wireless framework telecommunication code name beep wireless framework telecommunication beep implementation xmpp protocol mobile devices enable two roaming mobile devices positioned two different locations exchange data order communication stream successful mobile devices must connected internet wireless technology regardless wireless technologies using internet acts middle carrier developers trying best offer communication services highest possible quality relieve user paying current high costs communication moreover project empower client mobile device roaming capabilities allowing mobile device easily locate initiate interaction session another mobile device within unlimited range beep implementation generic high level abstract well-defined framework supports wireless communication internet enabling two roaming mobile devices exchange data necessarily using wireless technology use protocol enable developers program application run top protocol exchange data different types licensed gnu general public license gpl
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Internet protocols
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ziften ziften cybersecurity software company based austin texas united states organization endpoint protection platform designed provide advanced anti-virus endpoint detection response endpoint visibility hardening enterprise laptops desktops servers cloud ziften founded 2009 mark obrecht previously founded whole security behavior-based security anti-phishing company sold symantec 2005 july 2011 ziften raised 5.8 million capital series round trellis partners fayez sarofim co may 2012 ziften raised 5.5 million capital series b round fayez sarofim co july 2015 ziften raised 24 million capital new york-based spring mountain capital lp fayez sarofim co april 2017 ziften raised additional 14.7m trousdale ventures organization total funding date 50m mike hamilton previously ziften chief product officer appointed ceo june 2018 september 2017 ziften announced series managed security services called managed assess service managed hunt service managed respond service designed help organizations augment security teams getting additional help monitoring edr analytics security forensics november 2017 microsoft announced new partnerships windows defender advanced threat protection atp service including integration ziften zenith security platform macos linux operating system support integration provides security events onboarded macos linux devices surfaces within windows defender atp console ziften later included member initial formation microsoft intelligent security association august 2018 ziften enhanced zenith endpoint protection platform advanced anti-virus capabilities new capabilities help block file-based file-less in-memory attacks zenith uses artificial intelligence ai cloud help protect enterprises
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Computer security
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national cybersecurity center excellence national cybersecurity center excellence nccoe us government organization builds publicly shares solutions cybersecurity problems faced u.s. businesses center located rockville maryland established 2012 partnership national institute standards technology nist state maryland montgomery county center partnered nearly 20 market-leading companies contribute hardware software expertise nccoe asks industry sector members cybersecurity problems selects issues affect entire sector reaches across sectors center forms team people cybersecurity technology companies federal agencies academia address problem teams work center ’ labs build example solutions using commercially available off-the-shelf products example solution nccoe publishes practice guide collection materials information needed deploy example solution makes available general public center ’ goal “ accelerate deployment use secure technologies ” help businesses improve defenses cyber attack nccoe part nist non-regulatory federal agency within u.s. department commerce develops measurement standards conducts research measurement science according nist website federal information security management act 2002 fisma “ reaffirmed nist ’ role developing information security standards federal information processing standards guidelines non-national security federal information systems assigned nist specific responsibilities including development standards used federal agencies categorize information information systems based objectives providing appropriate levels information security according range risk levels guidelines recommending types information information systems included category minimum information security requirements management operational technical security controls information information systems category. ” many private sector organizations voluntarily adopt standards guidelines security requirements nist center nccoe applied space demonstration standards-based approaches cybersecurity president barack obama issued executive order 13636 “ improving critical infrastructure cybersecurity ” february 2013 tasking nist create cybersecurity framework helps organizations mitigate risks nation ’ essential systems power generation distribution financial services sector transportation nist released framework improving critical infrastructure cybersecurity february 2014 “ consists standards guidelines practices promote protection critical infrastructure. ” nccoe demonstrates framework implemented real-world environments industrial sector approaches center cybersecurity problem center maps solution ’ hoped-for capabilities cybersecurity framework well standards controls best practices nccoe ’ launch formally announced february 21 2012 u.s senator barbara mikulski d-md maryland lt governor anthony brown montgomery county executive isiah leggett secretary commerce standards technology nist director patrick d. gallagher nist issued press release day stating center created “ work strengthen u.s. economic growth supporting automated trustworthy e-government e-commerce. ” nccoe “ host multi-institutional collaborative efforts build expertise industry government ” according press release september 2014 national institute standards technology nist awarded contract mitre corporation operate department commerce ’ first federally funded research development center ffrdc national cybersecurity ffrdc supports nccoe according press release nist website “ ffrdc first solely dedicated enhancing security nation ’ information systems. ” press release states ffrdc help nccoe “ expand accelerate public-private collaborations ” focus “ boosting security u.s. information systems. ” “ ffrdcs operate public interest required free organizational conflicts interest well bias toward particular company technology product—key attributes given nccoe ’ collaborative nature…the first three task orders contract allow nccoe expand efforts developing use cases building blocks provide operations management facilities planning. ” partners founded nccoe national institute standards technology nist state maryland montgomery county partnership instrumental establishing center nationally recognized cybersecurity resource potential increase number local cybersecurity companies local workforce development provide local companies exposure nist ’ expertise national cybersecurity excellence partners nceps offer technology companies opportunity develop long-term relationships nccoe nist core partners nceps provide hardware software personnel collaborate nccoe current projects sector representatives approach nccoe behalf industry share business problems solved cybersecurity solution representatives also provide insight project build process help validate center ’ approach developing example solution members government agencies academic institutions discuss cybersecurity challenges nccoe provide insight feedback existing center projects collaborate technology companies center ’ labs users businesses working improve cybersecurity opportunity test nccoe ’ example solutions evaluate effectiveness provide feedback
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Computer security
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cryptonote cryptonote application layer protocol aims solve problems outlined bitcoin core protocol behind bitcoin protocol powers several decentralized privacy-oriented cryptocurrencies nothing known original author cryptonote nicolas van saberhagen
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Internet protocols
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national collegiate cyber defense competition national collegiate cyber defense competition nccdc championship event collegiate cyber defense competition system – largest college-level cyber defense competition usa event held annually san antonio area effort help facilitate development regular national level cyber security exercise center infrastructure assurance security university texas san antonio utsa hosted first collegiate cyber defense competition southwestern region may 2005 june 29 2010 united states house legislature passed recognizing national ccdc promoting cyber security curriculum similar cyber defense competitions many aspects nccdc unique focuses operational aspect managing protecting existing network infrastructure exercises examine abilities group students design configure protect network course entire semester competition focused operational task assuming administrative protective duties existing commercial network teams assessed based ability detect respond outside threats maintain availability existing services mail servers web servers respond business requests addition removal additional services balance security needs business needs nccdc operated rules published center infrastructure assurance utsa current rules found homepage several regional groups formed provide qualifying events nccdc annual event regions share overlap various states every effort made make regional event consistent nccdc event
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Computer security
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crfs crfs coherent remote file system network file system protocol zach brown formerly oracle intended leverage btrfs architecture gain higher performance existing protocols nfs smb expose btrfs features snapshots remote clients code unmaintained one looking network file system top btrfs number options available active support development including ceph beegfs glusterfs samba
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Computer file systems
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hacker computer hacker skilled computer expert uses technical knowledge overcome problem hacker refer skilled computer programmer term become associated popular culture security hacker someone technical knowledge uses bugs exploits break computer systems reflecting two types hackers two definitions word hacker today mainstream usage hacker mostly refers computer criminals due mass media usage word since 1980s includes hacker slang calls script kiddies people breaking computers using programs written others little knowledge way work usage become predominant general public largely unaware different meanings exist self-designation hobbyists hackers generally acknowledged accepted computer security hackers people programming subculture consider computer intrusion related usage incorrect emphasize difference two calling security breakers crackers analogous safecracker controversy usually based assertion term originally meant someone messing something positive sense using playful cleverness achieve goal supposed meaning term shifted decades came refer computer criminals security-related usage spread widely original meaning become less known popular usage media computer intruders computer criminals exclusive meaning word today example internet 'hacker broke state government security systems march computer enthusiast hacker culture community primary meaning complimentary description particularly brilliant programmer technical expert example linus torvalds creator linux considered hacker large segment technical community insist latter correct usage word see jargon file definition mainstream media current usage term may traced back early 1980s term introduced wider society mainstream media 1983 even computer community referred computer intrusion hacking although exclusive definition word reaction increasing media use term exclusively criminal connotation computer community began differentiate terminology alternative terms cracker coined effort maintain distinction hackers within legitimate programmer community performing computer break-ins terms black hat white hat gray hat developed laws breaking computers came effect distinguish criminal activities activities legal however network news use term consistently pertained primarily criminal activities despite attempt technical community preserve distinguish original meaning today mainstream media general public continue describe computer criminals levels technical sophistication hackers generally make use word non-criminal connotations members media sometimes seem unaware distinction grouping legitimate hackers linus torvalds steve wozniak along criminal crackers result definition still subject heated controversy wider dominance pejorative connotation resented many object term taken cultural jargon used negatively including historically preferred self-identify hackers many advocate using recent nuanced alternate terms describing criminals others negatively take advantage security flaws software hardware others prefer follow common popular usage arguing positive form confusing unlikely become widespread general public minority still use term senses despite controversy leaving context clarify leave ambiguous meaning intended however positive definition hacker widely used predominant form many years negative definition popularized hacker therefore seen shibboleth identifying use technically-oriented sense opposed exclusively intrusion-oriented sense members computing community hand due variety industries software designers may find many prefer referred hackers word holds negative denotation many industries possible middle ground position suggested based observation hacking describes collection skills tools used hackers descriptions differing reasons analogy made locksmithing specifically picking locks skill used good evil primary weakness analogy inclusion script kiddies popular usage hacker despite lack underlying skill knowledge base sometimes hacker simply used synonymously geek true hacker group person person loves stay night machine love-hate relationship ... 're kids tended brilliant interested conventional goals ... term derision also ultimate compliment fred shapiro thinks common theory 'hacker originally benign term malicious connotations word later perversion untrue found malicious connotations already present mit 1963 quoting tech mit student newspaper time referred unauthorized users telephone network phreaker movement developed computer security hacker subculture today hacker culture idea derived community enthusiast computer programmers systems designers 1960s around massachusetts institute technology mit tech model railroad club tmrc mit artificial intelligence laboratory concept expanded hobbyist home computing community focusing hardware late 1970s e.g homebrew computer club software video games software cracking demoscene 1980s/1990s later would go encompass many new definitions art life hacking security hackers people involved circumvention computer security among security hackers several types including white hats hackers work keep data safe hackers finding system vulnerabilities mitigated white hats usually employed target system owner typically paid sometimes quite well work work illegal done system owner consent black hats crackers hackers malicious intentions often steal exploit sell data usually motivated personal gain work usually illegal cracker like black hat hacker specifically someone skilled tries via hacking make profits benefit vandalize crackers find exploits system vulnerabilities often use advantage either selling fix system owner selling exploit black hat hackers turn use steal information gain royalties grey hats include hack fun troll may fix exploit vulnerabilities usually financial gain even malicious work still illegal done without target system owner consent grey hats usually associated black hat hackers four primary motives proposed possibilities hackers attempt break computers networks first criminal financial gain hacking systems specific purpose stealing credit card numbers manipulating banking systems second many hackers thrive increasing reputation within hacker subculture leave handles websites defaced leave evidence proof involved specific hack third corporate espionage allows companies acquire information products services stolen used leverage within marketplace fourth state-sponsored attacks provide nation states wartime intelligence collection options conducted cyberspace main basic difference programmer subculture computer security hacker mostly separate historical origin development however jargon file reports considerable overlap existed early phreaking beginning 1970s article mit student paper tech used term hacker context already 1963 pejorative meaning someone messing phone system overlap quickly started break people joined activity less responsible way case publication article exposing activities draper engressia according raymond hackers programmer subculture usually work openly use real name computer security hackers prefer secretive groups identity-concealing aliases also activities practice largely distinct former focus creating new improving existing infrastructure especially software environment work latter primarily strongly emphasize general act circumvention security measures effective use knowledge report help fixing security bugs exploitation reasons rather secondary visible difference views design mit hackers incompatible timesharing system deliberately security measures subtle overlaps however since basic knowledge computer security also common within programmer subculture hackers example ken thompson noted 1983 turing award lecture possible add code unix login command would accept either intended encrypted password particular known password allowing backdoor system latter password named invention trojan horse furthermore thompson argued c compiler could modified automatically generate rogue code make detecting modification even harder compiler program generated compiler trojan horse could also automatically installed new compiler program without detectable modification source new compiler however thompson disassociated strictly computer security hackers would like criticize press handling 'hackers 414 gang dalton gang etc acts performed kids vandalism best probably trespass theft worst ... watched kids testifying congress clear completely unaware seriousness acts programmer subculture hackers sees secondary circumvention security mechanisms legitimate done get practical barriers way actual work special forms even expression playful cleverness however systematic primary engagement activities one actual interests programmer subculture hackers significance actual activities either difference historically members programmer subculture hackers working academic institutions used computing environment contrast prototypical computer security hacker access exclusively home computer modem however since mid-1990s home computers could run unix-like operating systems inexpensive internet home access available first time many people outside academic world started take part programmer subculture hacking since mid-1980s overlaps ideas members computer security hacking community prominent case robert t. morris user mit-ai yet wrote morris worm jargon file hence calls true hacker blundered nevertheless members programmer subculture tendency look disassociate overlaps commonly refer disparagingly people computer security subculture crackers refuse accept definition hacker encompasses activities computer security hacking subculture hand tends distinguish two subcultures harshly acknowledging much common including many members political social goals love learning technology restrict use term cracker categories script kiddies black hat hackers instead three subcultures relations hardware modifications early days network hacking phreaks building blue boxes various variants programmer subculture hackers stories several hardware hacks folklore mysterious 'magic switch attached pdp-10 computer mit ai lab turned crashed computer early hobbyist hackers built home computers construction kits however activities died 1980s phone network switched digitally controlled switchboards causing network hacking shift dialing remote computers modems pre-assembled inexpensive home computers available academic institutions started give individual mass-produced workstation computers scientists instead using central timesharing system kind widespread hardware modification nowadays case modding encounter programmer computer security hacker subculture occurred end 1980s group computer security hackers sympathizing chaos computer club disclaimed knowledge activities broke computers american military organizations academic institutions sold data machines soviet secret service one order fund drug addiction case solved clifford stoll scientist working system administrator found ways log attacks trace back help many others 23 german film adaption fictional elements shows events attackers perspective stoll described case book cuckoo egg tv documentary kgb computer perspective according eric s. raymond nicely illustrates difference 'hacker 'cracker stoll portrait lady martha friends berkeley internet paints marvelously vivid picture hackers people around like live think
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Computer security
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michael kerrisk michael kerrisk technical author programmer since 2004 maintainer linux man-pages project succeeding andries brouwer born 1961 new zealand lives munich germany kerrisk worked digital equipment google linux foundation editor writer lwn.net currently works freelance consultant trainer best known book linux programming interface published starch press 2010 book widely regarded definitive work linux system programming translated several languages maintainer linux man-pages project kerrisk authored co-authored third man pages worked improving project infrastructure contributions received special award 2016 new zealand open source awards
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Operating systems
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palm vii palm vii personal digital assistant made palm computing division 3com device featured antenna used wireless data communication first palm device connectivity provided mobitex network defunct palm.net service web clipping applications also known palm query applications pqas made use network request post web data devices also provided pqa developers user position form zipcode making palm vii first web-enabled location-based services mobile platform cost service 14.95 per month allowed limited number web pages viewed palm vii expensive palm sold date unit pricing starting us 599 despite high price tag palm vii proved popular one first truly wireless data-capable information devices
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Computer architecture
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amulet microprocessor amulet series microprocessors implementing arm processor architecture developed advanced processor technologies group school computer science university manchester formerly amulet pal groups based institution amulet unique amongst arm implementations asynchronous microprocessor making use square wave clock signal data synchronization movement
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Computer architecture
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sift workstation digital forensics incident response distribution sift computer forensics distribution installs necessary tools ubuntu perform detailed digital forensic incident response examination compatible expert witness format e01 advanced forensic format aff raw dd memory analysis evidence formats toolkit ability securely examine raw disks multiple file systems evidence formats places strict guidelines evidence examined read-only verifying evidence changed
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Computer security
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p programming language p programming language developed microsoft uc berkeley p enables programmers specify systems consisting collection state machines communicate asynchronously terms events code run microsoft windows windows phone open source
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Programming language topics
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graphics device interface graphics device interface gdi microsoft windows application programming interface core operating system component responsible representing graphical objects transmitting output devices monitors printers gdi responsible tasks drawing lines curves rendering fonts handling palettes directly responsible drawing windows menus etc task reserved user subsystem resides user32.dll built atop gdi systems components similar gdi example macos quartz x window system xlib/xcb gdi significant advantages direct methods accessing hardware perhaps scaling capabilities abstract representation target devices using gdi easy draw multiple devices screen printer expect proper reproduction case capability center see get applications microsoft windows simple games require fast graphics rendering may use gdi however gdi relatively hard use advanced animation lacks notion synchronizing individual video frames video card lacks hardware rasterization 3d etc modern games usually use directx opengl instead let programmers exploit features modern hardware device context dc used define attributes text images output screen printer actual context maintained gdi handle device context hdc obtained output written released elements written gdi uses bresenham line drawing algorithm draw aliased lines gdi present initial release windows ms-dos programs hitherto manipulated graphics hardware using software interrupts sometimes via video bios manipulating video memory directly code written way expects user video memory tenable windowed system like microsoft windows multiple applications would want write subwindows concurrently byte december 1983 discussed microsoft plans system output graphics printers monitors code forthcoming first release windows introduction windows xp gdi complemented c++-based gdi+ subsystem gdi+ adds anti-aliased 2d graphics floating point coordinates gradient shading complex path management intrinsic support modern graphics-file formats like jpeg png support composition affine transformations 2d view pipeline gdi+ uses argb values represent color use features apparent windows xp user interface several applications microsoft paint windows picture fax viewer photo printing wizard pictures slideshow screensaver presence basic graphics layer greatly simplifies implementations vector-graphics systems flash svg gdi+ included versions windows windows xp gdi+ dynamic library also shipped application used older versions windows windows 98 windows nt 4.0 onwards additional text processing resolution independence capabilities gdi+ text rendering performed cpu nearly order magnitude slower hardware accelerated gdi chris jackson published tests indicating piece text rendering code written could render 99,000 glyphs per second gdi code using gdi+ rendered 16,600 glyphs per second microsoft .net class library provides managed interface gdi+ via codice_1 namespace gdi+ similar purpose structure apple quickdraw gx subsystem open-source libart cairo libraries windows vista windows applications including gdi gdi+ applications run new compositing engine desktop window manager dwm built atop windows display driver model gdi rendering implemented canonical display driver cdd.dll draws system memory surfaces redirected dwm gdi longer hardware-accelerated video card driver however due nature desktop composition internal management moving bitmaps transparency anti-aliasing gdi+ handled dwm core operations like window moves faster responsive underlying content need re-rendered application windows 7 includes gdi hardware acceleration blitting operations windows display driver model v1.1 improves gdi performance canonical display driver allows dwm engine use local video memory compositing thereby reducing system memory footprint increasing performance graphics operations primitive gdi operations still hardware-accelerated unlike direct2d november 2009 amd nvidia released wddm v1.1 compatible video drivers gdi+ continues rely software rendering windows 7 gdi printer winprinter analogous winmodem printer designed accept output host computer running gdi windows host computer print processing gdi software renders page bitmap sent software printer driver usually supplied printer manufacturer processing particular printer printer combination gdi driver bidirectional receive information printer whether ready print paper ink non-gdi printers require hardware firmware memory page rendering gdi printer uses host computer making cheaper manufacture similar non-gdi printer manufacturers produce essentially printer version compatible printer control language pcl postscript cheaper gdi-only version cases lowest-cost models given manufacturer range support gdi printer control language accept input device suitable driver gdi printer requires pc running windows compatible hardware operating systems general gdi printers compatible hardware print servers although servers built-in processing capability making compatible specified gdi printers gdi printers made available computers network connected shared printers computer running windows generic gdi drivers pnm2ppa written make gdi printers compatible non-windows operating systems freebsd guarantee particular gdi printer supported order allow simpler creation drivers winprinters microsoft universal printer driver created allows printer vendors write generic printer description gpd minidrivers describe printer capabilities command set plaintext rather kernel mode driver development time window opened consumes gdi objects complexity window increases additional features buttons images gdi object usage also increases many objects use windows unable draw gdi objects leading misbehaving software frozen unresponsive program operation many applications also incorrectly coded fail release gdi objects use adds problem total available gdi objects varies one version windows next windows 95 98 millennium limit 1,200 total objects windows 2000 limit 16,384 objects windows xp vista windows 7 configurable limit via registry defaults 10,000 objects per process theoretical maximum 65,536 entire session windows 8 8.1 increase gdi object limit 65,536 per user logon session earlier versions windows windows 3.1 windows 98 included resource meter program allow user monitor much total system gdi resources use unfortunately resource meter consumed gdi objects later versions windows 2000 windows xp report gdi object usage program task manager tell user total gdi capacity available overflowing gdi capacity affect windows preventing new windows opening menus displaying alert boxes appearing situation difficult clear potentially require forced hard-reset system since prevents core system programs functioning windows 8 8.1 forced logoffs occur result gdi capacity overflow instead hard reboot example forcing frozen process end using task manager normally makes sure alert window appear free gdi windows beeps error alert choice appear gdi-overflowing processes terminated unless user uses taskkill command direct2d directwrite designed replace gdi/gdi+ uniscribe respectively screen-oriented rendering shipped windows 7 windows server 2008 r2 well windows vista windows server 2008 platform update installed wpf/uwp based-application win2d gdi like class library developed microsoft downloaded inside visual studio using nuget win2d easy-to-use windows runtime api immediate mode 2d graphics rendering gpu acceleration
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Operating systems
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ncsa httpd ncsa httpd early discontinued web server originally developed ncsa university illinois urbana–champaign robert mccool others first released 1993 among earliest web servers developed following tim berners-lee cern httpd tony sanders plexus server others time natural counterpart mosaic web browser client–server world wide web also introduced common gateway interface allowing creation dynamic websites robert mccool left ncsa mid-1994 development ncsa httpd slowed greatly independent effort apache project took codebase continued meanwhile ncsa released one version 1.5 ceased development august 1995 ncsa httpd powered web servers internet nearly quickly switched apache april 1996 apache passed ncsa httpd 1 server internet retained position mid-to-late 2016
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Web technology
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fifth-generation programming language fifth-generation programming language 5gl programming language based problem solving using constraints given program rather using algorithm written programmer constraint-based logic programming languages declarative languages fifth-generation languages fourth-generation programming languages designed build specific programs fifth-generation languages designed make computer solve given problem without programmer way user needs worry problems need solved conditions need met without worrying implement routine algorithm solve fifth-generation languages used mainly artificial intelligence research ops5 mercury examples fifth-generation languages types languages also built upon lisp many originating lisp machine icad many frame languages kl-one 1980s fifth-generation languages considered way future predicted would replace languages system development exception low-level languages notably 1982 1993 japan put much research money fifth-generation computer systems project hoping design massive computer network machines using tools however larger programs built flaws approach became apparent turns given set constraints defining particular problem deriving efficient algorithm solve difficult problem crucial step yet automated still requires insight human programmer vendors known occasion advertise languages 5gl time actually sell 4gls higher level automation knowledge base hype 1980s faded away projects eventually dropped 5gl awareness also dropped opened doors vendors re-use term marketing new tools without causing much controversy among current generations programmers
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Programming language topics
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mitchell wand mitchell wand computer science professor northeastern university received ph.d. massachusetts institute technology research centred programming languages member northeastern programming research lab also co-author daniel p. friedman christopher t. haynes essentials programming languages
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Programming language topics
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maple software maple symbolic numeric computing environment also multi-paradigm programming language developed maplesoft maple also covers aspects technical computing including visualization data analysis matrix computation connectivity toolbox maplesim adds functionality multidomain physical modeling code generation users enter mathematics traditional mathematical notation custom user interfaces also created support numeric computations arbitrary precision well symbolic computation visualization examples symbolic computations given maple incorporates dynamically typed imperative-style programming language resembles pascal language permits variables lexical scope also interfaces languages c c fortran java matlab visual basic also interface excel maple supports mathml 2.0 w3c format representing interpreting mathematical expressions including display web pages maple based small kernel written c provides maple language functionality provided libraries come variety sources libraries written maple language viewable source code many numerical computations performed nag numerical libraries atlas libraries gmp libraries different functionality maple requires numerical data different formats symbolic expressions stored memory directed acyclic graphs standard interface calculator interface written java first concept maple arose meeting november 1980 university waterloo researchers university wished purchase computer powerful enough run macsyma instead decided would develop computer algebra system would able run lower cost computers first limited version appearing december 1980 maple demonstrated first conferences beginning 1982 name reference maple canadian heritage end 1983 50 universities copies maple installed machines 1984 research group arranged watcom products inc license distribute first commercially available version maple 3.3 1988 waterloo maple inc. founded company ’ original goal manage distribution software eventually company evolved r department maple development done today rest done university research labs worldwide including symbolic computation laboratory university waterloo ontario research centre computer algebra university western ontario 1989 first graphical user interface maple developed included version 4.3 macintosh x11 windows versions new interface followed 1990 maple v. 1992 maple v release 2 introduced maple worksheet combined text graphics input typeset output 1994 special issue newsletter created maple developers called mapletech published 1999 release maple 6 maple included nag numerical libraries 2003 current standard interface introduced maple 9 interface primarily written java although portions rules typesetting mathematical formulae written maple language java interface criticized slow improvements made later versions although maple 11 documentation recommends previous classic interface users less 500 mb physical memory mid 1995 2005 maple lost significant market share competitors due weaker user interface 2005 maple 10 introduced new document mode part standard interface developed following years september 2009 maple maplesoft acquired japanese software retailer cybernet systems features maple include sample imperative programming constructs simple functions also defined using maps arrow notation find answer compute determinant matrix series tanh x x=0,15 high order polynomial equation plot x*sin x x=-10..10 plot3d x^2+y^2 x=-1..1 y=-1..1 plots -animate subs k .5 f x=-30..30 t=-10..10 numpoints=200 frames=50 color=red thickness=3 plots -animate3d cos t*x *sin 3*t*y x=-pi..pi y=-pi..pi t=1..2 matrix 400,400,200 100,100 -400 1,1,1 datatype=float 8 plot3d 1 x=0..2*pi y=0..pi axes=none coords=spherical viewpoint= path=m f 1+a*t+b*t^2 *exp c*t find functions formula_17 satisfy integral equation maple engine used within several products maplesoft listed third-party commercial products longer use maple engine
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Programming language topics
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comparison linux distributions technical variations linux distributions include support different hardware devices systems software package configurations organizational differences may motivated historical reasons criteria include security including quickly security upgrades available ease package management number packages available tables compare notable distribution latest stable release wide-ranging objective criteria cover operating system subjective merits branches marked unstable beta compare linux distributions operating systems table shows general information distributions creator producer release date latest version etc linux distributions endorsed free software foundation marked 100 free system distribution commitment column table shows default file system many linux distributions support ext2 ext3 ext4 btrfs reiserfs reiser4 jfs xfs gfs2 ocfs2 nilfs possible install linux onto file systems ext file systems namely ext2 ext3 ext4 based original linux file system file systems developed companies meet specific needs hobbyists adapted unix microsoft windows operating systems linux full support xfs jfs fat dos file system hfs main file system macintosh support microsoft windows nt ntfs file system developed comparable native unix file systems cds dvds blu-ray discs iso 9660 universal disk format udf supported unlike operating systems linux unix allow file system regardless medium stored whether medium magnetic disk optical disk cd dvd etc usb flash memory key even contained within file located another file system similarly many c compilers mainly gnu compiler collection gcc init systems mainly sysvinit desktop environments window managers widely supported linux kernel portability instruction set architectures x86 early feature added kernel information features distributions package numbers approximate distributions like debian tend separate tools different packages usually stable release development release documentation debug also counting source package number varies debian rpm based entries base produce binary packages total number packages number binary packages arch based entries additional e.g arch linux provides 11'000 47'000 packages i.e 58'000 packages
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Operating systems
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international merchant marine registry belize international merchant marine registry belize immarbe body appointed government belize register ships belizean flag
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Databases
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cyberoam cyberoam technologies sophos company global network security appliances provider presence 125 countries company offers user identity-based network security firewalls/ unified threat management appliances allowing visibility granular control users activities business networks soho smb large enterprise networks ensures security built around network user protection apts insider threats malware hacker sophisticated network attacks cyberoam sales offices north america emea apac company customer support development centers india 550+ employees across globe channel-centric approach sales global network 4500+ partners company also conducts training programs customers partners cyberoam ’ product range offers network security solution firewall utm appliances centralized security management cyberoam central console appliances centralized visibility cyberoam iview cyberoam netgenie home small office networks cyberoam network security appliances include multiple features like firewall – vpn ssl vpn ipsec gateway anti-virus anti-spyware anti-spam intrusion prevention system ips content application filtering web application firewall application visibility control bandwidth management multiple link management load balancing gateway failover single platform cyberoam offers visibility control 2000+ key applications offers complete visibility applications accessed within organization user irrespective ports protocols stops sophisticated application-layer threats right network perimeter ensuring application security granular controls applications ensure qos critical applications cyberoam utm ’ on-appliance reporting gives details every type attack vector attacker details victim details also graphically represents general security trends organization cyberoam solutions aid compliance regulatory needs organizations cyberoam firewall technology eal4+ certified eal4+ certification security product firewall requires in-depth evaluation independent third-party test lab globally regarded decisive measure quality security product cyberoam gsmc global iso 20000 2011 certified post sales technical services global customers cyberoam cr series utm level 5 checkmark certified cyberoam firewall certified icsa labs firewall certification icsa labs firewall certification demands required icsa labs independent division cybertrust validating cyberoam ’ firewall capabilities effectively protecting customers ’ networks malicious internet threats cyberoam ‘ ipv6 ready ’ certified identify process ipv6 traffic ipv6 ready logo program driven ipv6 forum international testing program 3000 test cases product rigorously tested cyberoam patented layer 8 technology also known identity based security adds 8th layer human layer network protocol stack thereby considering user ’ identity part firewall rule matching criteria cyberoam attaches user identity security authenticating authorizing auditing aaa network allowing network administrator see control ‘ user ’ network instead ip address enables administrators identify users control internet activity users network set user based policies reporting username cyberoam launched global mission sign academies bridge demand-supply gap network security recently called cyberoam academy order propagate knowledge identity-based technology among upcoming networking students cyberoam tied nescot north east surrey college technology -its first master uk training academy nescot offers cyberoam certified security courses includes basic-level course namely 'ccnsp cyberoam certified security professional advanced-level course namely 'ccnse cyberoam certified security expert cyberoam threat research labs ctrl identifies security threats eventually raising resistance various vulnerabilities malware attacks publishing security upgrades research reports reports help users remain protected detailed guidance malware threat prevention advice using appropriate configuration parameters cyberoam appliances ctrl goes beyond finding emerging potential threats aims providing insightful investigation advanced threats engineered imagined around today ’ internet usage apps tor project researcher google software security engineer revealed july 2012 cyberoam appliances ssl traffic inspection capabilities using self-generated ca certificate default made possible intercept traffic victim cyberoam device cyberoam device indeed extract key device import dpi deep packet inspection devices use interception cyberoam issued over-the-air ota update unified threat management utm appliances order force devices use unique certificate authority ca ssl certificates intercepting ssl traffic corporate networks hotfix applied individual appliance required unique ca certificate
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Computer security
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hypercard hypercard software application development kit apple macintosh apple iigs computers among first successful hypermedia systems predating world wide web hypercard combines flat-file database graphical flexible user-modifiable interface hypercard includes built-in programming language called hypertalk manipulating data user interface combination features – database simple form layout flexible support graphics ease programming – suits hypercard many different projects rapid application development applications databases interactive applications database requirements command control systems many examples demoscene hypercard originally released 1987 49.95 included free new macs sold withdrawn sale march 2004 received final update 1998 upon return steve jobs apple hypercard runs classic environment ported mac os x. hypercard based concept stack virtual cards cards hold data would rolodex card-filing device card contains set interactive objects including text fields check boxes buttons similar common graphical user interface gui elements users browse stack navigating card card using built-in navigation features powerful search mechanism user-created scripts users build modify stacks adding new cards place gui objects cards using interactive layout engine based simple drag-and-drop interface also hypercard includes prototype template cards called backgrounds new cards created refer one background cards causes objects background copied onto new card way stack cards common layout functionality created layout engine similar concept form used rapid application development rad environments borland delphi microsoft visual basic visual studio database features hypercard system based storage state objects cards physical file representing stack database exist separate system within hypercard stack database engine similar construct exists instead state object system considered live editable time hypercard runtime perspective difference moving text field card typing operations simply change state target object within stack changes immediately saved complete typing field causes text stored stack physical file system operates largely stateless fashion need save operation common many database-oriented systems although somewhat different document-based applications final key element hypercard script single code-carrying element every object within stack script text field whose contents interpreted hypertalk language like property script object edited time changes saved soon complete user invokes actions gui like clicking button typing field actions translated events hypercard runtime runtime examines script object target event like button see script object contains event code called handler hypertalk engine runs handler runtime examines objects visual hierarchy concepts make majority hypercard system stacks backgrounds cards provide form-like gui system stack file provides object persistence database-like functionality hypertalk allows handlers written gui events unlike majority rad database systems era however hypercard combines features user-facing developer-facing single application allows rapid turnaround immediate prototyping possibly without coding allowing users author custom solutions problems personalized interface empowerment became catchword possibility embraced macintosh community phrase programming rest us anyone professional programmers combination features also makes hypercard powerful hypermedia system users build backgrounds suit needs system say rolodex use simple hypertalk commands provide buttons move place place within stack provide navigation system within data elements ui like text fields using features easy build linked systems similar hypertext links web unlike web programming placement browsing tool similar systems created html traditional web services considerably heavyweight hypercard contains object oriented scripting language called hypertalk hypertalk object classes predetermined hypercard environment although others added use externals weakly typed hypertalk supports standard programming structures if-then repeat hypertalk verbose hence ease use readability hypertalk code segments referred scripts term considered less daunting beginning programmers hypercard extended significantly use external command xcmd external function xfcn modules code libraries packaged resource fork integrate either system generally hypertalk language specifically early example plug-in concept unlike conventional plug-ins require separate installation available use included stack directly available scripts stack hypercard peak popularity late 1980s whole ecosystem vendors offered thousands externals hypertalk compilers graphing systems database access internet connectivity animation oracle offered xcmd allows hypercard directly query oracle databases platform superseded oracle card beehive technologies offered hardware interface allows computer control external devices connected via apple desktop bus adb instrument read state connected external switches write digital outputs multitude devices externals allow access macintosh toolbox contains many lower-level commands functions native hypertalk control serial adb ports hypercard created bill atkinson following lsd trip work began march 1985 name wildcard hence creator code wild 1986 dan winkler began work hypertalk name changed hypercard trademark reasons initially released august 1987 understanding atkinson would give hypercard apple company promised release free macs apple timed release coincide macworld conference expo boston massachusetts guarantee maximum publicity hypercard successful almost instantly apple programmer developer association apda said hypercard informational feeding frenzy august 1987 announced october phones never stopped ringing zoo within months release multiple hypercard books 50 disk set public domain stacks apple project managers found hypercard used huge number people internally externally bug reports upgrade suggestions continued flow demonstrating wide variety users since also free difficult justify dedicating engineering resources improvements software apple mainstream developers understood hypercard user empowerment could reduce sales ordinary shrink-wrapped products stewart alsop ii speculated hypercard might replace finder macintosh graphical user interface late 1989 kevin calhoun hypercard engineer apple led effort upgrade program resulted hypercard 2.0 released 1990 new version included on-the-fly compiler greatly increased performance computationally intensive code new debugger many improvements underlying hypertalk language time hypercard 2.0 developed separate group within apple developed 1991 released hypercard iigs version hypercard apple iigs system aimed mainly education market hypercard iigs roughly feature set 1.x versions macintosh hypercard adding support color graphics abilities iigs although stacks hypercard program documents binary-compatible translator program another hypercard stack allows moved one platform apple decided application software packages including hypercard would property wholly owned subsidiary called claris many hypercard developers chose stay apple rather move claris causing development team split claris attempted create business model hypercard could also generate revenues first freely-distributed versions hypercard shipped authoring disabled early versions claris hypercard contain easter egg typing magic message box converts player full hypercard authoring environment trick became nearly universal wrote new version hypercard player apple distributed macintosh operating system claris sold full version commercially many users upset pay use software traditionally supplied free many considered basic part mac even hypercard generating revenue claris little market development continued minor upgrades first failed attempt create third generation hypercard period hypercard began losing market share without several important basic features hypercard authors began moving systems supercard macromedia authorware nonetheless hypercard continued popular used widening range applications game manhole earlier effort creators myst corporate information services apple eventually folded claris back parent company returning hypercard apple core engineering group 1992 apple released eagerly anticipated upgrade hypercard 2.2 included licensed versions color tools addmotion ii adding support color pictures animations however tools limited often cumbersome use hypercard 2.0 lacks true internal color support several attempts made restart hypercard development returned apple product widespread use multimedia-authoring tool rolled quicktime group new effort allow hypercard create quicktime interactive qti movies started direction kevin calhoun qti extended quicktime core multimedia playback features provide true interactive facilities low-level programming language based 68000 assembly language resulting hypercard 3.0 first presented 1996 alpha-quality version shown developers apple annual apple worldwide developers conference wwdc leadership dan crow development continued late 1990s public demos showing many popular features color support internet connectivity ability play hypercard stacks special quicktime movies web browser development upon hypercard 3.0 stalled quicktime team focused away developing quicktime interactive streaming features quicktime 4.0. 1998 steve jobs disliked software atkinson chosen stay apple finish instead joining jobs next according atkinson sculley stink 2000 hypercard engineering team reassigned tasks jobs decided abandon product calhoun crow left apple shortly 2001 final release 1998 totally discontinued march 2004 hypercard runs natively classic mac os still used mac os x classic mode powerpc based machines g5 earlier last functional native hypercard authoring environment classic mode mac os x 10.4 tiger powerpc-based machines hypercard used range hypertext artistic purposes advent powerpoint hypercard often used general-purpose presentation program examples hypercard applications include simple databases choose adventure -type games educational teaching aids due rapid application design facilities hypercard also often used prototyping applications sometimes even version 1.0 implementations inside apple quicktime team one hypercard biggest customers hypercard lower hardware requirements macromedia director several commercial software products created hypercard notably original version interactive game narrative myst voyager company expanded books multimedia cd-roms beethoven ninth symphony cd-rom hard day night beatles voyager macbeth early electronic edition whole earth catalog implemented hypercard stored cd-rom prototype demo popular game n't know jack written hypercard french auto manufacturer renault used control inventory system quebec canada hypercard used control robot arm used insert retrieve video disks national film board cinérobothèque hypercard used prototype fully functional prototype sidoci one first experiments world develop integrated electronic patient record system heavily used montréal consulting firm dmr demonstrate typical day life patient get surgery would look like paperless age activision mainly game company saw hypercard entry point business market changing name mediagenic published several major hypercard-based applications notably danny goodman focal point personal information manager reports hypercard program nine five software allows users treat hypercard full database system robust information viewing printing features hypercard-inspired supercard included roadster plug-in allowed stacks placed inside web pages viewed web browsers appropriate browser plug-in even windows version plug-in allowing computers macintoshes use plug-in first hypercard virus discovered belgium netherlands april 1991 hypercard executed scripts stacks immediately opening also one first applications susceptible macro viruses merryxmas virus discovered early 1993 ken dunham two years concept virus viruses based hypercard overall impact minimal compute apple applications 1987 stated hypercard may make macintosh personal computer choice noting large memory requirement made best suited computers 2 mb memory hard drives magazine predicted smallest programming shop able turn stackware especially using cd-roms compute predicted 1988 future mac software would developed using hypercard using addictive developers wo n't able tear away long enough create anything else byte 1989 listed among excellence winners byte awards stating like first entry flaws magazine wrote hypercard opened new category software praised apple bundling every mac 2001 steve wozniak called hypercard best program ever written hypercard one first products made use popularized hypertext concept large popular base users jakob nielsen pointed hypercard really hypermedia program since links started regions card text objects actual html-style text hyperlinks possible later versions awkward implement seldom used deena larsen programmed links hypercard marble springs bill atkinson later lamented realized power network-oriented stacks instead focusing local stacks single machine hypercard could become first web browser hypercard saw loss popularity growth world wide web since web could handle deliver data much way hypercard without limited files local hard disk hypercard significant impact web inspired creation http influence tim berners-lee colleague robert cailliau javascript whose creator brendan eich inspired hypertalk also key inspiration violawww early web browser pointing-finger cursor used navigating stacks later used first web browsers hyperlink cursor myst computer game franchise initially released hypercard stack included bundled macs example performa 5300 still lives making hypercard facilitating technology starting one best-selling computer games time according ward cunningham inventor wiki wiki concept traced back hypercard stack wrote late 1980s 2017 internet archive established project preserve emulate hypercard stacks allowing users upload gui prototype apple wizzy active lifestyle telephone based hypercard hypercard influenced development web late 1990 influence robert cailliau assisted developing tim berners-lee first web browser javascript inspired hypertalk although hypercard stacks operate internet 1988 least 300 stacks publicly available download commercial compuserve network connected official internet yet system link phone numbers user computer together enable dial numbers without modem using less expensive piece hardware hyperdialer sense like web form association-based experience information browsing via links though operating remotely tcp/ip protocol like web also allows connections many different kinds media companies offered versions four products available offer hypercard-like abilities past products include addition many basic concepts original system later re-used forms apple built system-wide scripting engine applescript language similar hypertalk often used desktop publishing dtp workflow automation needs 1990s facespan provided third-party graphical interface applescript also native graphical programming front-end called automator released mac os x tiger april 2005 one hypercard strengths handling multimedia many multimedia systems like macromedia authorware macromedia director based concepts originating hypercard appware originally named serius developer sometimes seen similar hypercard rapid application development rad systems appware sold early 90s worked mac windows systems
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Programming language topics
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sqx sqx-archiver open free data compression archival format used one applications free charge license royalty free homepage provides sdk source compiled dlls likewise unencumbered license costs format designed speedproject squeez also supported tugzip
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Computer file systems
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matthew flatt matthew flatt american computer scientist professor university utah school computing salt lake city also member core development team racket programming language flatt received phd rice university 1999 direction matthias felleisen dissertation mechanics first-class modules mixin classes work triggered research ml community mutually recursive modules object-oriented community mixins traits flatt served one four editors revised^6 report scheme programming language report influenced design racket especially module system exception system record system macro system library links
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Programming language topics
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semantic web data space semantic web data space container domain specific portable data provided human and/or machine friendly structures data data space referenced identifier linked data across spaces domains thus viewed object-oriented fashion underlying paradigm brings together ideas technologies various sources approach applied web based systems desktop-based systems data data spaces linked across spaces domains enhance meaning internal data supports work linked data project part semantic web effort benefit useful point querying information across domains assists development web data data space fully supportive data portability advocated dataportability project means object data space movable also ability referenced using identifier uniform resource identifier
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Distributed computing architecture
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joint cyber-defence command joint cyber-defence command mccd spanish cyber defence service defence staff responsible planning execution actions related cyber defence networks information telecommunications systems ministry defense others might entrusted well contributing adequate response cyberspace threats aggressions may affect national defense sense mccd directs coordinates matter cyber defense activity centers response incidents security information different branches armed forces exercises timely legitimate proportionate response cyberspace threats aggressions may affect national defense defines directs coordinates awareness training specialized training area addition responsible development detail information security policies information telecommunications systems seginfosit direction execution control compliance policies within scope ministry defense mccd created february 19 2013 defence ministry order 10/2013 joint cyber-defence command created current chief commander mccd divisional general rafael garcía hernández functions joint cyber defence command joint cyber defense command composed following bodies
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Computer security
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unrar unrar name two different command-line applications extracting rar file archives source-available freeware windows command-line version unrar created rarlab company created commercial winrar software software extract newer rar v5.0 file archives supported competitors free software linux version unrar based old version rarlab unrar permission author eugene roshal licensed gpl support rar3 format
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Computer file systems
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shell builtin computing shell builtin command function called shell executed directly shell instead external executable program shell would load execute shell builtins work significantly faster external programs program loading overhead however code inherently present shell thus modifying updating requires modifications shell therefore shell builtins usually used simple almost trivial functions text output nature operating systems functions systems must necessarily implemented shell builtins notable example codice_1 command changes working directory shell since executable program runs separate process working directories specific process loading codice_1 external program would affect working directory shell loaded widely used shell-builtin codice_3 function terminates session function different names depending shell
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Operating systems
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richard wexelblat richard l. wexelblat aka dick wexelblat american artisanal woodturner former computer scientist wexelblat received bsee msee cs ph.d. cs moore school electrical engineering university pennsylvania 6/1959 6/1961 12/1965 respectively doctorate believed many reported acm first ever awarded formally recognized computer science department note first cs doctorate first awarded cs department andy van dam share distinction completed cs dissertation essentially time left computer field become artisanal woodturner said originator wexelblat scheduling algorithm choose two good fast cheap stated bob rosin said originated 'm sure also credited first refer occam razor 'the law least astonishment sons alan david brother paul also computer scientists although paul mostly retired david halfway law school
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Programming language topics
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pacemaker software pacemaker open-source high availability resource manager software used computer clusters since 2004 2007 part linux-ha project split project implements several apis controlling resources preferred api purpose open cluster framework resource agent api pacemaker generally used corosync cluster engine linux-ha heartbeat
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Distributed computing architecture
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