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bios parameter block computing bios parameter block often shortened bpb data structure volume boot record vbr describing physical layout data storage volume partitioned devices hard disks bpb describes volume partition whereas unpartitioned devices floppy disks describes entire medium basic bpb appear used partition including floppy disks presence often necessary however certain filesystems also make use describing basic filesystem structures filesystems making use bios parameter block include fat12 except dos 1.x fat16 fat32 hpfs ntfs due different types fields amount data contain length bpb different fat16 fat32 ntfs boot sectors detailed discussion various fat bpb versions entries found fat article combined 11-byte data structure start volume boot records immediately preceding bpb ebpb also called fdc descriptor extended fdc descriptor ecma-107 iso/iec 9293 describes fat flexible/floppy optical disk cartridges format standard dos 2.0 bpb fat12 13 bytes format standard dos 3.0 bpb fat12 fat16 19 bytes already supported versions ms-dos 2.11 format standard dos 3.2 bpb fat12 fat16 21 bytes format standard dos 3.31 bpb fat12 fat16 fat16b 25 bytes format pc dos 3.4 os/2 1.0-1.1 extended bpb fat12 fat16 fat16b 32 bytes format dos 4.0 os/2 1.2 extended bpb fat12 fat16 fat16b hpfs 51 bytes format short dos 7.1 extended bios parameter block 60 bytes fat32 format full dos 7.1 extended bios parameter block 79 bytes fat32 format extended bpb ntfs 73 bytes
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Operating systems
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java api xml processing computing java api xml processing jaxp one java xml application programming interfaces api provides capability validating parsing xml documents three basic parsing interfaces addition parsing interfaces api provides xslt interface provide data structural transformations xml document jaxp developed java community process jsr 5 jaxp 1.0 jsr 63 jaxp 1.1 1.2 jsr 206 jaxp 1.3 jaxp version 1.4.4 released september 3 2010 jaxp 1.3 declared end-of-life february 12 2008 dom interface parses entire xml document constructs complete in-memory representation document using classes modeling concepts found document object model dom level 2 core specification dom parser called codice_1 builds in-memory codice_2 representation javax.xml.parsers.documentbuilder created javax.xml.parsers.documentbuilderfactory codice_1 creates instance tree structure containing nodes xml document tree node structure implements interface among many different types tree nodes representing type data found xml document important include javax.xml.parsers.saxparserfactory creates sax parser called saxparser unlike dom parser sax parser create in-memory representation xml document runs faster uses less memory instead sax parser informs clients xml document structure invoking callbacks invoking methods org.xml.sax.helpers.defaulthandler instance provided parser way accessing document called streaming xml codice_4 class implements contenthandler errorhandler dtdhandler entityresolver interfaces clients interested methods defined codice_5 interface called sax parser encounters corresponding elements xml document important methods interface clients provide subclass codice_4 overrides methods processes data may involve storing data database writing stream parsing parser may need access external documents possible store local cache frequently used documents using xml catalog introduced java 1.3 may 2000 stax designed median dom sax interface metaphor programmatic entry point cursor represents point within document application moves cursor forward 'pulling information parser needs different event based api sax 'pushes data application requiring application maintain state events necessary keep track location within document xml stylesheet language transformations xslt allows conversion xml document forms data jaxp provides interfaces package javax.xml.transform allowing applications invoke xslt transformation interface originally called trax transformation api xml developed informal collaboration developers number java xslt processors main features interface two abstract interfaces source result defined represent input output transformation somewhat unconventional use java interfaces since expectation processor accept class implements interface processor choose kinds source result prepared handle practice jaxp processors support three standard kinds source codice_12 codice_13 codice_14 three standard kinds result codice_15 codice_16 codice_17 possibly implementations primitive complete example xslt transformation launching may look like applies following hardcoded xslt transformation following hardcoded xml document result execution
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Programming language topics
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g data software g data software ag german software company focuses computer security company founded 1985 headquartered bochum known creators world first antivirus software g data use multiple scanning engines one developed in-house bitdefender engine g data provides several security products targeted home business markets company north american subsidiary located atlanta georgia g data founded bochum germany 1985 company introduced first computer security product anti-virus kit avk 1988 atari st. beside focus security market g data also created software voice recognition invox speech synthesis logox g data computer security products use two scan-engines originally avast bitdefender 2014 release introduced scan-engine closegap replaced avast however upgrade new version painless users weaker computers experienced system slowdowns company promptly solved issue update september 2015 g data launched new messaging app called secure chat used signal protocol application based fork signal source code published gplv3 license g data discontinued service may 2018 features g data solutions support
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Computer security
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goatse security goatse security goatsec loose-knit nine-person grey hat hacker group specializes uncovering security flaws division anti-blogging internet trolling organization known gay nigger association america gnaa group derives name goatse.cx shock site chose gaping holes exposed slogan june 2010 goatse security obtained email addresses approximately 114,000 apple ipad users led fbi investigation filing criminal charges two group members gnaa several security researchers within membership according goatse security spokesperson leon kaiser gnaa could fully utilize talents since group believed would anyone would take security data published gnaa seriously order create medium gnaa members publish security findings gnaa created goatse security december 2009 order protect web browser inter-protocol exploitation mozilla blocked several ports html forms would normally access january 2010 gnaa discovered mozilla blocks cover port 6667 left mozilla browsers vulnerable cross-protocol scripts gnaa crafted javascript-based exploit order flood irc channels although efnet oftc able block attacks freenode struggled counteract attacks goatse security exposed vulnerability one members andrew auernheimer aka weev posted information exploit encyclopedia dramatica march 2010 goatse security discovered integer overflow vulnerability within apple web browser safari posted exploit encyclopedia dramatica found person could access blocked port adding 65,536 port number vulnerability also found arora icab omniweb stainless although apple fixed glitch desktop versions safari march company left glitch unfixed mobile versions browser goatse security claimed hacker could exploit mobile safari flaw order gain access cause harm apple ipad june 2010 goatse security uncovered vulnerability within website provider 3g service apple ipad united states time signing 3g service ipad retrieves icc-id ipad sim card associates email address provided sign-up order ease log-in process ipad website receives sim card icc-id pre-populates email address field address provided sign-up goatse security realized sending http request valid icc-id embedded inside website website would reveal email address associated icc-id june 5 2010 daniel spitler aka jacksonbrown began discussing vulnerability possible ways exploit including phishing irc channel goatse security constructed php-based brute force script would send http requests random icc-ids website legitimate icc-id entered would return email address corresponding icc-id script dubbed ipad 3g account slurper goatse security attempted find appropriate news source confide leaked information weev attempted contact news corporation thomson reuters executives including arthur siskind security problems june 6 2010 weev sent emails icc-ids recovered order verify claims chat logs period also reveal attention publicity may incentives group contrary first claimed group initially revealed security flaw gawker media notifying also exposed data 114,000 ipad users including celebrities government military tactics re-provoked significant debate proper disclosure security flaws weev maintained goatse security used common industry standard practices said tried good guys jennifer granick electronic frontier foundation also defended tactics used goatse security june 14 2010 michael arrington techcrunch awarded group crunchie award public service first time crunchie awarded outside annual crunchies award ceremony fbi opened investigation incident leading criminal complaint january 2011 raid andrew weev auernheimer house search related investigation auernheimer subsequently detained released bail state drug charges later dropped release bail broke gag order protest dispute legality search house denial access public defender also asked donations via paypal defray legal costs 2011 department justice announced charged one count conspiracy access computer without authorization one count fraud co-defendant daniel spitler released bail november 20 2012 auernheimer found guilty one count identity fraud one count conspiracy access computer without authorization tweeted would appeal ruling alex pilosov friend also present ruling tweeted auernheimer would remain free bail sentencing least 90 days november 29 2012 auernheimer authored article wired magazine entitled forget disclosure hackers keep security holes advocating disclosure zero-day exploit individuals use interests social justice april 11 2014 third circuit issued opinion vacating auernheimer conviction basis venue new jersey improper judges address substantive question legality site access released prison late april 11 may 2011 dos vulnerability affecting several linux distributions disclosed goatse security group discovered lengthy advanced packaging tool url would cause compiz crash september 2012 goatse security credited microsoft helping secure online services
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Computer security
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flash gordon video game flash gordon video game based comic book character name game published 1986 mastertronic amstrad cpc commodore 64 zx spectrum msx personal computers zzap 64 praised commodore 64 version game reviewers appreciated gameplay variety offered three different sections game quality graphics sound rated 89 overall also 1982 game tie 1980 film released atari 2600 oct. 7 2015 mobile game also based film released infinite runner type game developed boluga limited featured three songs queen flash ’ theme vultan ’ theme football fight flash gordon also 1990 defenders earth video game enigma variations
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Computer architecture
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whql testing windows hardware quality labs testing whql testing microsoft testing process involves running series tests third-party hardware software submitting log files tests microsoft review procedure may also include microsoft running tests wide range equipment different hardware different microsoft windows editions products pass whql tests get use certified windows logotype certifies hardware software share testing microsoft ensure compatibility actual logo used depends version microsoft windows device drivers passing whql tests microsoft creates digitally signed certification file included driver installation package allows installation 64-bit versions windows prevents 32-bit versions versions displaying warning message driver certified microsoft see screenshot right new since june 2007 requirement audio fidelity test equipment audio precision sys-2722-a-m system submissions company choose sign drivers rather go whql testing process drivers would qualify certified windows logos would install 64-bit versions windows install without warning message 32-bit versions however install without warning message device drivers passed whql tests also made available download using windows update microsoft update catalog detects new device built-in drivers show found new hardware wizard see screenshot right one way avoid found new hardware wizard popping pre-installing whql certified driver device plugged microsoft longer requires whql testing fee used usd 250 per operating system family fee covers 32-bit x86 64-bit x64 versions submitted simultaneously non-refundable fee include expenses windows server 2008 x64 license necessary running whql tests verisign certificate necessary submitting test results sometimes ambiguity responsible providing drivers supported case industry standard devices used much broadly pc platform microsoft supply drivers example whql bluetooth stereo headsets
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Operating systems
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matrix protocol matrix open standard lightweight protocol real-time communication designed allow users accounts one communications service provider communicate users different service provider via online chat voice ip videotelephony aims make real-time communication work seamlessly different service providers like standard simple mail transfer protocol email store-and-forward email service technical perspective application layer communication protocol federated real-time communication provides http apis open source reference implementations securely distributing persisting messages json format open federation servers integrate standard web services via webrtc facilitating browser-to-browser applications initial project created inside amdocs building chat tool called amdocs unified communications matthew hodgson amandine le pape amdocs funded development work 2014 october 2017 matrix winner innovation award webrtc 2014 conference expo best show award webrtc world 2015 protocol received praise mixed cautionary notes launched 2014 reviewers noted attempts defining open instant messaging multimedia signalling protocol type difficulties becoming widely adopted—e.g xmpp ircv3—and highlighted challenges involved technological political unclear enough demand among users services interoperate among providers 2015 subsidiary amdocs created named vector creations limited matrix staff moved july 2017 funding amdocs announced cut following weeks core team created uk-based company new vector mainly built support matrix riot development time period multiple calls support community companies build matrix help pay wages least part core team patreon liberapay crowdfunding accounts created core team started video podcast called matrix live keep contributors speed ongoing developments expanded weekly blog format called week matrix interested community members could read submit matrix-related news company created goal offering consultancy services matrix paid hosting matrix servers platform called modular.im generate income early weeks creation matrix team company purism published plans collaborate creation librem 5 phone librem 5 intended matrix native phone default pre-installed messaging caller app use matrix audio video calls instant messaging 2017 kde announced working including support protocol irc client konversation late january 2018 company received investment us 5 million status ethereum based startup april 2018 french government announced plans create instant messaging tool later confirmed matrix team based riot matrix new vector said provide support government endeavour october 2018 private company limited guarantee called matrix.org foundation incorporated serve neutral legal entity development standard february 2019 kde community announced adopt matrix internal communications needs decentralized alternative modern tools like telegram slack discord operate server instance april 2019 matrix.org suffered security breach production servers compromised breach issue matrix protocol directly affect homeservers matrix.org june 2019 matrix protocol beta version 1.0 across apis synapse time reference homeserver matrix foundation officially launched matrix targets use cases like voice ip internet things instant messaging including group communication along longer-term goal generic messaging data synchronization system web protocol supports security replication maintaining full conversation history single points control failure existing communication services integrate matrix ecosystem client software available open-federated instant messaging im voice ip voip internet things iot communication matrix standard specifies restful http apis securely transmitting replicating json data matrix-capable clients servers services clients send data puting ‘ room ’ server replicates data matrix servers participating ‘ room ’ data signed using git-style signature mitigate tampering federated traffic encrypted https signed server ’ private key avoid spoofing replication follows eventual consistency semantics allowing servers function even offline data-loss re-synchronizing missing history participating servers olm library provides optional end-to-end encryption room-by-room basis via double ratchet algorithm implementation ensure conversation data rest readable room participants configured data transmitted matrix visible ciphertext matrix servers decrypted authorized participants room olm megolm expansion olm better suit need bigger rooms libraries subject cryptographic review ncc group whose findings publicly available addressed matrix team review sponsored open technology fund matrix support bridging messages different chat applications matrix rooms bridges programs run server communicate non-matrix servers bridges either acting puppets relays former individual users account visibly posting messages latter bot posts messages non puppeteered user accounts currently official bridges following bridges maintained community riot reference implementation client fractal official client gnome desktop many clients bots bridges servers implementations matrix protocol also exist
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Internet protocols
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fortran fortran formerly fortran derived formula translation general-purpose compiled imperative programming language especially suited numeric computation scientific computing originally developed ibm 1950s scientific engineering applications fortran came dominate area programming early continuous use six decades computationally intensive areas numerical weather prediction finite element analysis computational fluid dynamics computational physics crystallography computational chemistry popular language high-performance computing used programs benchmark rank world fastest supercomputers fortran encompasses lineage versions evolved add extensions language usually retaining compatibility prior versions successive versions added support structured programming processing character-based data fortran 77 array programming modular programming generic programming fortran 90 high performance fortran fortran 95 object-oriented programming fortran 2003 concurrent programming fortran 2008 fortran design basis many programming languages among better known basic based fortran ii number syntax cleanups notably better logical structures changes work easily interactive environment names earlier versions language fortran 77 conventionally spelled all-capitals fortran 77 last version use lowercase letters keywords strictly non-standard capitalization dropped referring newer versions beginning fortran 90 official language standards refer language fortran rather all-caps fortran late 1953 john w. backus submitted proposal superiors ibm develop practical alternative assembly language programming ibm 704 mainframe computer backus historic fortran team consisted programmers richard goldberg sheldon f. best harlan herrick peter sheridan roy nutt robert nelson irving ziller harold stern lois haibt david sayre concepts included easier entry equations computer idea developed j. halcombe laning demonstrated laning zierler system 1952 programmers chess players chosen work ibm thought logical minds draft specification ibm mathematical formula translating system completed november 1954 first manual fortran appeared october 1956 first fortran compiler delivered april 1957 first optimizing compiler customers reluctant use high-level programming language unless compiler could generate code performance comparable hand-coded assembly language community skeptical new method could possibly outperform hand-coding reduced number programming statements necessary operate machine factor 20 quickly gained acceptance john backus said 1979 interview think ibm employee magazine much work come lazy n't like writing programs working ibm 701 writing programs computing missile trajectories started work programming system make easier write programs language widely adopted scientists writing numerically intensive programs encouraged compiler writers produce compilers could generate faster efficient code inclusion complex number data type language made fortran especially suited technical applications electrical engineering 1960 versions fortran available ibm 709 650 1620 7090 computers significantly increasing popularity fortran spurred competing computer manufacturers provide fortran compilers machines 1963 40 fortran compilers existed reasons fortran considered first widely used cross-platform programming language development fortran paralleled early evolution compiler technology many advances theory design compilers specifically motivated need generate efficient code fortran programs initial release fortran ibm 704 contained 32 statements including arithmetic statement reminiscent readily implementable three-way comparison instruction cas compare accumulator storage available 704 statement provided way compare numbers testing difference attendant risk overflow deficiency later overcome logical facilities introduced fortran iv statement used originally optionally give branch probabilities three branch cases arithmetic statement first fortran compiler used weighting perform compile time monte carlo simulation generated code results used optimize placement basic blocks memory sophisticated optimization time monte carlo technique documented backus et al paper original implementation fortran automatic coding system fundamental unit program basic block basic block stretch program one entry point one exit point purpose section 4 prepare section 5 table predecessors pred table enumerates basic blocks lists every basic block basic blocks immediate predecessor flow together absolute frequency basic block link table obtained running program monte-carlo fashion outcome conditional transfers arising if-type statements computed go determined random number generator suitably weighted according whatever frequency statements provided many years later statement effect code treated comment statement since compilers longer kind compile-time simulation similar fate befallen compiler hints several programming languages example c keyword first fortran compiler reported diagnostic information halting program error found outputting error code console code could looked programmer error messages table operator manual providing brief description problem later error handling subroutine handle users error division zero developed nasa incorporated giving users feedback line code error appeared development disk files text editors terminals programs often entered keypunch keyboard onto 80-column punched cards one line card resulting deck cards would fed card reader compiled punched card codes included lower-case letters many special characters special versions ibm 026 keypunch offered would correctly print re-purposed special characters used fortran reflecting punched card input practice fortran programs originally written fixed-column format first 72 columns read twelve 36-bit words letter c column 1 caused entire card treated comment ignored compiler otherwise columns card divided four fields columns 73 80 could therefore used identification information punching sequence number text could used re-order cards stack cards dropped though practice reserved stable production programs ibm 519 could used copy program deck add sequence numbers early compilers e.g. ibm 650 additional restrictions due limitations card readers keypunches could programmed tab column 7 skip column 72 later compilers relaxed fixed-format restrictions requirement eliminated fortran 90 standard within statement field whitespace characters blanks ignored outside text literal allowed omitting spaces tokens brevity including spaces within identifiers clarity example valid identifier equivalent 101010do101i=1,101 valid statement equivalent 10101 101 1 101 zero column 6 treated space 101010do101i=1.101 instead 10101 do101i 1.101 assignment 1.101 variable called do101i note slight visual difference comma period hollerith strings originally allowed format data statements prefixed character count letter h e.g. allowing blanks retained within character string miscounts problem ibm fortran ii appeared 1958 main enhancement support procedural programming allowing user-written subroutines functions returned values parameters passed reference common statement provided way subroutines access common global variables six new statements introduced next years fortran ii would also add support data types early fortran compilers supported recursion subroutines early computer architectures supported concept stack directly support subroutine calls return location often stored one fixed location adjacent subroutine code e.g ibm 1130 specific machine register ibm 360 et seq allows recursion stack maintained software return address stored stack call made restored call returns although specified fortran 77 many f77 compilers supported recursion option burroughs mainframes designed recursion built-in default became standard fortran 90 via new keyword recursive program heron formula reads data tape reel containing three 5-digit integers b c input type declarations available variables whose name starts j k l n fixed-point i.e integers otherwise floating-point since integers processed example names variables start letter name variable must start letter continue letters digits limit six characters fortran ii b c represent sides triangle plane geometry program execution end error code stop 1 otherwise output line printed showing input values b c followed computed area triangle floating-point number occupying ten spaces along line output showing 2 digits decimal point .2 f10.2 format statement label 601 c area triangle standard square root function c input tape reader unit 5 integer input c output line printer unit 6 real output c input error display error output code 1 job control listing c ia ib ic may negative zero c furthermore sum two sides triangle c must greater third side check c using heron formula calculate c area triangle ibm also developed fortran iii 1958 allowed inline assembly code among features however version never released product like 704 fortran fortran ii fortran iii included machine-dependent features made code written unportable machine machine early versions fortran provided vendors suffered disadvantage fortran provided ibm 1401 computer innovative 63-phase compiler ran entirely core memory 8000 six-bit characters compiler could run tape 2200-card deck used tape disk storage kept program memory loaded overlays gradually transformed place executable form described haines article reprinted edited editions anatomy compiler ibm manual fortran specifications operating procedures ibm 1401 executable form entirely machine language rather floating-point arithmetic sub-scripting input/output function references interpreted preceding ucsd pascal p-code two decades ibm later provided fortran iv compiler 1400 series computers starting 1961 result customer demands ibm began development fortran iv removed machine-dependent features fortran ii adding new features data type logical boolean expressions logical statement alternative arithmetic statement fortran iv eventually released 1962 first ibm 7030 stretch computer followed versions ibm 7090 ibm 7094 later ibm 1401 1966 1965 fortran iv supposed compliant standard developed american standards association x3.4.3 fortran working group 1966 1968 ibm offered several fortran iv compilers system/360 named letters indicated minimum amount memory complier needed run letters f g h matched codes used system/360 model numbers indicate memory size letter increment factor two larger time fortran iv started become important educational tool implementations university waterloo watfor watfiv created simplify complex compile link processes earlier compilers perhaps significant development early history fortran decision american standards association american national standards institute ansi form committee sponsored bema business equipment manufacturers association develop american standard fortran resulting two standards approved march 1966 defined two languages fortran based fortran iv served de facto standard basic fortran based fortran ii stripped machine-dependent features fortran defined first standard officially denoted x3.9-1966 became known fortran 66 although many continued term fortran iv language standard largely based fortran 66 effectively became first industry-standard version fortran fortran 66 included release fortran 66 standard compiler vendors introduced several extensions standard fortran prompting ansi committee x3j3 1969 begin work revising 1966 standard sponsorship cbema computer business equipment manufacturers association formerly bema final drafts revised standard circulated 1977 leading formal approval new fortran standard april 1978 new standard called fortran 77 officially denoted x3.9-1978 added number significant features address many shortcomings fortran 66 revision standard number features removed altered manner might invalidate formerly standard-conforming programs removal allowable alternative x3j3 time since concept deprecation yet available ansi standards 24 items conflict list see appendix a2 x3.9-1978 addressed loopholes pathological cases permitted prior standard rarely used small number specific capabilities deliberately removed dimension 10,5 control data corporation computers another version fortran 77 called minnesota fortran mnf designed especially student use variations output constructs special uses commons data statements optimizations code levels compiling detailed error listings extensive warning messages debugs development revised standard succeed fortran 77 would repeatedly delayed standardization process struggled keep rapid changes computing programming practice meantime standard fortran nearly fifteen years fortran 77 would become historically important dialect important practical extension fortran 77 release mil-std-1753 1978 specification developed u.s. department defense standardized number features implemented fortran 77 compilers included ansi fortran 77 standard features would eventually incorporated fortran 90 standard ieee 1003.9 posix standard released 1991 provided simple means fortran 77 programmers issue posix system calls 100 calls defined document allowing access posix-compatible process control signal handling file system control device control procedure pointing stream i/o portable manner much-delayed successor fortran 77 informally known fortran 90 prior fortran 8x finally released iso/iec standard 1539:1991 1991 ansi standard 1992 addition changing official spelling fortran fortran major revision added many new features reflect significant changes programming practice evolved since 1978 standard unlike prior revision fortran 90 removed features appendix b.1 says list deleted features standard empty standard-conforming fortran 77 program also standard-conforming fortran 90 either standard usable define behavior small set features identified obsolescent expected removed future standard functionalities early version features performed new fortran 95 features kept simplify porting old programs may eventually deleted fortran 95 published officially iso/iec 1539-1:1997 minor revision mostly resolve outstanding issues fortran 90 standard nevertheless fortran 95 also added number extensions notably high performance fortran specification number intrinsic functions extended example argument added intrinsic several features noted fortran 90 obsolescent removed fortran 95 important supplement fortran 95 iso technical report tr-15581 enhanced data type facilities informally known allocatable tr specification defined enhanced use arrays prior availability fully fortran 2003-compliant fortran compilers uses include arrays derived type components procedure dummy argument lists function return values arrays preferable -based arrays arrays guaranteed fortran 95 deallocated automatically go scope eliminating possibility memory leakage addition elements allocatable arrays contiguous aliasing issue optimization array references allowing compilers generate faster code case pointers another important supplement fortran 95 iso technical report tr-15580 floating-point exception handling informally known ieee tr specification defined support ieee floating-point arithmetic floating point exception handling addition mandatory base language defined iso/iec 1539-1 1997 fortran 95 language also includes two optional modules together compose multi-part international standard iso/iec 1539 according standards developers optional parts describe self-contained features requested substantial body users and/or implementors deemed sufficient generality required standard-conforming fortran compilers nevertheless standard-conforming fortran provide options must provided accordance description facilities appropriate part standard fortran 2003 officially published iso/iec 1539-1:2004 major revision introducing many new features comprehensive summary new features fortran 2003 available fortran working group iso/iec jtc1/sc22/wg5 official web site article major enhancements revision include important supplement fortran 2003 iso technical report tr-19767 enhanced module facilities fortran report provided sub-modules make fortran modules similar modula-2 modules similar ada private child sub-units allows specification implementation module expressed separate program units improves packaging large libraries allows preservation trade secrets publishing definitive interfaces prevents compilation cascades iso/iec 1539-1:2010 informally known fortran 2008 approved september 2010 fortran 95 minor upgrade incorporating clarifications corrections fortran 2003 well introducing select new capabilities new capabilities include final draft international standard fdis available document n1830 important supplement fortran 2008 iso technical specification ts 29113 interoperability fortran c submitted iso may 2012 approval specification adds support accessing array descriptor c allows ignoring type rank arguments latest revision language fortran 2018 earlier referred fortran 2015 significant revision released november 28 2018 fortran 2018 incorporates two previously published technical specifications additional changes new features include support iso/iec/ieee 60559:2011 latest version ieee floating point standard 2019 hexadecimal input/output implicit none enhancements changes although 1968 journal article authors basic already described fortran old-fashioned fortran use several decades vast body fortran software daily use throughout scientific engineering communities jay pasachoff wrote 1984 physics astronomy students simply learn fortran much exists fortran seems unlikely scientists change pascal modula-2 whatever 1993 cecil e. leith called fortran mother tongue scientific computing adding replacement possible language may remain forlorn hope primary language intensive super-computing tasks astronomy climate modeling computational chemistry computational economics computational fluid dynamics computational physics data analysis hydrological modeling numerical linear algebra numerical libraries lapack imsl nag optimization satellite simulation structural engineering weather prediction many floating-point benchmarks gauge performance new computer processors cfp2006 floating-point component spec cpu2006 benchmarks written fortran apart modern codes computational science generally use large program libraries metis graph partitioning petsc trilinos linear algebra capabilities dune fenics mesh finite element support generic libraries since early 2000s many widely used support libraries also implemented c recently c++ hand high-level languages matlab python r become popular particular areas computational science consequently growing fraction scientific programs also written higher-level languages reason facilities inter-operation c added fortran 2003 enhanced iso/iec technical specification 29113 incorporated fortran 2018 shift popularity programming languages also evident selection applications spec cpu 2000 spec cpu 2006 floating point benchmarks software nasa probes voyager 1 voyager 2 originally written fortran 5 later ported fortran 77. software still written fortran ported c. precise characteristics syntax fortran 95 discussed fortran 95 language features portability problem early days agreed upon standard even ibm reference manual computer companies vied differentiate offerings others providing incompatible features standards improved portability 1966 standard provided reference syntax semantics vendors continued provide incompatible extensions although careful programmers coming realize use incompatible extensions caused expensive portability problems therefore using programs pfort verifier 1977 standard national bureau standards nist published fips pub 69 processors purchased u.s. government required diagnose extensions standard rather offer two processors essentially every compiler eventually least option diagnose extensions incompatible extensions portability problem numerical calculations important take account characteristics arithmetic addressed fox et al context 1966 standard port library ideas therein became widely used eventually incorporated 1990 standard way intrinsic inquiry functions widespread almost universal adoption ieee 754 standard binary floating-point arithmetic essentially removed problem access computing environment e.g. program command line environment variables textual explanation error conditions remained problem addressed 2003 standard large collections library software could described loosely related engineering scientific calculations graphics libraries written c therefore access presented portability problem addressed incorporation c interoperability 2003 standard possible relatively easy write entirely portable program fortran even without recourse preprocessor fortran 5 marketed data general corp late 1970s early 1980s nova eclipse mv line computers optimizing compiler quite good minicomputers time language closely resembles fortran 66 name pun earlier fortran iv fortran v distributed control data corporation 1968 cdc 6600 series language based upon fortran iv univac also offered compiler 1100 series known fortran v. spinoff univac fortran v athena fortran fortran 6 visual fortran 2001 licensed compaq microsoft licensed compaq visual fortran provided visual studio 5 environment interface compaq v6 v6.1 vendors high-performance scientific computers e.g. burroughs control data corporation cdc cray honeywell ibm texas instruments univac added extensions fortran take advantage special hardware features instruction cache cpu pipelines vector arrays example one ibm fortran compilers h extended iup level optimization reordered machine code instructions keep multiple internal arithmetic units busy simultaneously another example cfd special variant fortran designed specifically illiac iv supercomputer running nasa ames research center ibm research labs also developed extended fortran-based language called vectran processing vectors matrices object-oriented fortran object-oriented extension fortran data items grouped objects instantiated executed parallel available sun iris ipsc ncube longer supported machine-specific extensions either disappeared time elements incorporated main standards major remaining extension openmp cross-platform extension shared memory programming one new extension coarray fortran intended support parallel programming transit name reduced version ibm 704 fortran language implemented ibm 650 using translator program developed carnegie late 1950s following comment appears ibm reference manual transit automatic coding system c28-4038 copyright 1957 1959 ibm fortran system designed complex machine 650 consequently 32 statements found fortran programmer reference manual acceptable transit system addition certain restrictions fortran language added however none restrictions make source program written transit incompatible fortran system 704 permissible statements ten subroutines could used one program transit statements limited columns 7 56 punched cards used input output ibm 650 three passes required translate source code language compile statements soap assembly language finally produce object program could loaded machine run program using punched cards data input outputting results onto punched cards two versions existed 650s 2000 word memory drum transit transit ii latter machines equipped indexing registers automatic floating point decimal bi-quinary arithmetic appendix manual included wiring diagrams ibm 533 card reader/punch control panel prior fortran 77 number preprocessors commonly used provide friendlier language advantage preprocessed code could compiled machine standard fortran compiler preprocessors would typically support structured programming variable names longer six characters additional data types conditional compilation even macro capabilities popular preprocessors included flecs iftran mortran sftran s-fortran ratfor ratfiv ratfor ratfiv example implemented c-like language outputting preprocessed code standard fortran 66 despite advances fortran language preprocessors continue used conditional compilation macro substitution one earliest versions fortran introduced '60s popularly used colleges universities developed supported distributed university waterloo watfor based largely fortran iv student using watfor could submit batch fortran job syntax errors program would move straight execution simplification allowed students concentrate program syntax semantics execution logic flow rather dealing submission job control language jcl compile/link-edit/execution successive process es complexities mainframe/minicomputer environment side simplified environment watfor good choice programmers needing expanded abilities host processor e.g. watfor typically limited access i/o devices watfor succeeded watfiv later versions lrltran developed lawrence radiation laboratory provide support vector arithmetic dynamic storage among extensions support systems programming distribution included ltss operating system fortran-95 standard includes optional part 3 defines optional conditional compilation capability capability often referred coco many fortran compilers integrated subsets c preprocessor systems simscript application specific fortran preprocessor modeling simulating large discrete systems f programming language designed clean subset fortran 95 attempted remove redundant unstructured deprecated features fortran statement f retains array features added fortran 90 removes control statements made obsolete structured programming constructs added fortran 77 fortran 90 f described creators compiled structured array programming language especially well suited education scientific computing lahey fujitsu teamed create fortran microsoft .net framework silverfrost ftn95 also capable creating .net code following program illustrates dynamic memory allocation array-based operations two features introduced fortran 90 particularly noteworthy absence loops statements manipulating array mathematical operations applied array whole also apparent use descriptive variable names general code formatting conform contemporary programming style example computes average data entered interactively program average end program average fortran standards committee meeting name fortran 77 chosen satirical technical proposal incorporated official distribution bearing title letter considered harmful proposal purported address confusion sometimes arises letter numeral zero eliminating letter allowable variable names however method proposed eliminate letter character set entirely thereby retaining 48 number lexical characters colon increased 49 considered beneficial would promote structured programming making impossible use notorious statement troublesome statements would also eliminated noted might invalidate existing programs probably non-conforming anyway assumed-length arrays added dispute appropriate character separate upper lower bounds comment examining arguments dr. walt brainerd penned article entitled astronomy vs. gastroenterology proponents suggested using star asterisk others favored colon fortran 77 earlier versions variable names beginning letters i–n default type integer variables starting letters defaulted real although programmers could override defaults explicit declaration led joke fortran god real unless declared integer
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Programming language topics
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veronica search engine veronica search engine system gopher protocol released november 1992 steven foster fred barrie university nevada reno existence veronica constantly updated database names almost every menu item thousands gopher servers veronica database could searched major gopher menus although original veronica database longer accessible various local veronica installations least one complete rewrite veronica-2 still exist search engine named character veronica lodge archie comics intentional analogy naming archie search engine search engine ftp servers backronym veronica easy rodent-oriented net-wide index computer archives
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Internet protocols
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stonesoft corporation stonesoft corporation public company developed sold network security solutions based helsinki finland publicly owned 2013 acquired intel subsidiary mcafee stonesoft business globally regional headquarters atlanta georgia united states sales offices throughout europe middle east china july 2013 mcafee part intel security completed tender offer acquire stonesoft products technologies stonesoft became part mcafee network security business unit stonesoft firewall products renamed mcafee next generation firewall mcafee sold stonesoft forcepoint january 2016 stonesoft started systems integrator nordic regions europe 1994 introduced stonebeat technology creating high availability pair firewalls active-passive configuration 1999 company extended stonebeat patented load balancing clustering technology launching stonebeat fullcluster one first technologies certified check point opsec program 2001 stonesoft expanded product set firewall/vpn space becoming direct competitor check point stonegate firewall/vpn launched march 19 2001 january 2003 company introduced first virtual firewall/vpn solution ibm mainframes 2010 company released information via cert-fi advanced evasion technique aets met skepticism community aets released 2011 eventually verified independent labs researchers 2012 “ stonesoft ” replaced “ stonegate ” product name stonesoft used company product name stonesoft corporation product sales q3 2012 circa 5.6 million euros product sales grew approximately 18 q3 net sales approximately 9.2–9.3 million euros equals growth by14-16 growth lower expected product portfolio includes firewall/vpn devices ips intrusion detection prevention systems ssl vpn systems available hardware appliances software vmware-certified virtual appliances components well third-party devices managed stonesoft management center product portfolio differentiates unique clustering load balancing technologies based company older stonebeat technology originally developed check point firewall-1 stonesoft current product portfolio divided five major categories stonesoft firewall/vpn placed gartner magic quadrant enterprise network firewalls several years currently placed niche quadrant gartner notes stonesoft serves set placements well – usually high availability key leaders otherwise welcome stonesoft firewall/vpn regarded robust performance feature set relative company resources loyal customer base stonesoft ips also placed gartner magic quadrant network intrusion prevention currently “ visionaries ” quadrant also certified icsa labs network intrusion prevention detection category one four vendors consortium achieve certification stonesoft also received favorable reviews nss labs next generation firewall capability 2012 intrusion detection prevention system 2008 helsinki court appeal issued decision case brought stonesoft several members management team court held two members company board directors former ceo gross negligence failed give profit warning due time issue hand discrepancies profitability forecasted company year 2000 interim reports actual state company time reports indicated company sound profitable yet profit warning fact issued district court helsinki originally dismissed claims decision november 15 2006 2010 stonesoft informed public new evasion technique bypass security defences stonesoft defines advanced evasion techniques aets ” virtually limitless quantity unrecognizable conventional detection methods work levels tcp/ip stack work across many protocols protocol combinations. ” according max nyman stonesoft corporation senior marketing manager aets deliver malicious code without detection without leaving trace july 23 2012 stonesoft released free tool enables organisations test network security
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Computer security
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macjournal macjournal journaling blogging software originally developed mac os x published dan schimpf software macjournal offers basic text formatting limited page layout features macjournal audience includes diarists bloggers podcasters macjournal supports online blog tools including livejournal blogger movable type wordpress also contains powerful searching capabilities allows keeping multiple nested journals includes password protection aes-256 encryption palm pda syncing macjournal written dan schimpf awarded best mac os x student product 2002 apple design awards initially distributed freeware made shareware 2004 project purchased mariner software schimpf hired continue development 2012 macjournal given editors choice award macworld early 2019 development distribution macjournal reverted mariner software back original developer dan schimpf march 2019 dan schimpf software released version 7.0.0 macjournal freeware may 2019 schimpf continuing active development macjournal releasing occasional beta updates
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Internet protocols
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guided tour puzzle protocol guided tour puzzle gtp protocol cryptographic protocol mitigating application layer denial service attacks aims overcome shortcoming computation-based puzzle protocols clients required compute hard cpu memory-bound puzzles favor clients abundant computational resources guided tour puzzle protocol seen form proof-of-work pow protocol protocol steps guided tour puzzle protocol similar client puzzle protocol clients required complete guided tour puzzle prior receiving service server server suspects currently denial service attack load exceeds pre-defined threshold simply put guided tour puzzle tour needs completed taking multiple round-trips set special nodes called tour guides sequential order called guided tour order tour guides visited unknown client tour guide direct client towards next tour guide client complete tour correct order single tour guide may appear multiple times tour term stop used denote single appearance tour guide tour client knows tour guide next stop completing visit current stop solving guided tour puzzle essentially equal completing guided tour correct order starting first stop client contacts stop receives reply reply contains unique token token reply message current stop used computing address next stop tour guide address first stop tour guide computed using token contained server first reply message informs client start puzzle process client must send token received current stop tour guide next stop tour guide use input token calculation function token received last stop tour guide plus token server puzzle message sent server proof completion tour server efficiently validate two tokens grants service client proving validity guided tour puzzle start formula_1 tour guides set system formula_2 meanwhile server establishes shared secret formula_3 tour guide formula_4 using secure channel formula_5 server keeps short-lived secret formula_6 computing first hash value returned client part puzzle message puzzle message also contains length tour formula_7 used control difficulty guided tour puzzle figure shows example guided tour formula_8 formula_9 details protocol step guided tour puzzle protocol explained following cpu-bound computational puzzle protocols client puzzle protocol mitigate effect denial service attack attacker wants overwhelm server puzzles compute computational resources needs expend however due variation computational powers clients clients strong computational power solve puzzles much higher rate destitute clients unfairly take server resources another crucial shortcoming computational puzzle protocols clients including legitimate clients required perform cpu-intensive computations contribute meaningful service application guided tour puzzle protocol enforces delay clients round trip delays clients requests arrive rate sustainable server advantage using round-trip delays opposed hard computational problems round trip delay small packet determined mostly processing delays queuing delays propagation delays intermediate routers therefore beyond control end hosts clients even attacker abundant computational resources unfairly take advantage poorly provisioned legitimate clients furthermore guided tour puzzle protocol computation required client trivial since length guided tour usually small number order tens lower bandwidth overhead completing guided tour also trivial result clients burdened heavy computations usually required cpu-bound memory bound puzzle protocols
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Computer security
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report definition language report definition language rdl standard proposed microsoft defining reports rdl xml application primarily used microsoft sql server reporting services rdl usually written using visual studio although also third-party tools may also created edited hand text editor sql server reporting services 3rd party reporting frameworks use rdl define charts graphs calculations text images links report objects render variety formats three high-level sections typical rdl file
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Databases
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ibm websphere application server websphere application server software product performs role web application server specifically software framework middleware hosts java-based web applications flagship product within ibm websphere software suite initially created donald f. ferguson later became cto software dell first version launched 1998 websphere application server built using open standards java ee xml web services supported following platforms windows aix linux solaris ibm z/os beginning version 6.1 version 9.0 open standard specifications aligned common across platforms platform exploitation extent takes place done open standard specification line works number web servers including apache http server netscape enterprise server microsoft internet information services iis ibm http server i5/os ibm http server z/os ibm http server aix/linux/microsoft windows/solaris uses port 9060 connection default administration port port 9080 default website publication port case install websphere instances values changed traditional opposed liberty variant websphere application server platform architected distributed computing platform could installed multiple operating system instances collectively referred websphere cell management instances could done management node called deployment manager within cell deployment applications including ability perform rolling updates could pushed subset cell nodes configuration information entire cell many nodes applications deployed applications configured session management details resources etc tracked xml configuration files distributed throughout cell every node product lifetime implementation configuration details went files database-based around v3.5 back files around v5 given distributed install given also management entire cell required management local effects deployment logging configuration etc overall effect security could often override local security configured properly example earlier versions management console option available specify location log file remote node could used read write arbitrary file remote node reason advisable run application server node agent processes root privileges starting v6 security configuration defaulted box secure state even meant enabling desired functions required manual changing defaults originally nodes cell single domain management well application security however v6.1 support multiple security domains introduced ability separate administrative application security many ibm products ibm infosphere datastage use websphere application server base platform infrastructure ibm shipped several versions editions websphere application server first beta versions websphere called servlet express although versioning scheme x.1 x.5 would usually indicate minor release software industry websphere v6.1 v5.1 major releases like websphere v8.5 v3.5 websphere liberty introduced websphere application server v8.5 originally referred websphere liberty profile version numbering scheme rest 2016 ibm introduced new fix pack numbering scheme liberty reflect move continuous delivery liberty single support stream v8.5.5.9 liberty numbering scheme rebased starting 16.0.0.2 reflect year quarter liberty fixpack release common level websphere liberty distributed part version 8.5 version 9.0 websphere application server liberty continuous delivery model introduced allow new capabilities features delivered frequent basis.. websphere application server v9.0 adds java ee 7 java se 8 default also provides configured run java se 7 brought application server traditional level java ee websphere liberty offered since 2015 first release made simultaneously available on-premises offering websphere service ibm cloud.. websphere liberty increasingly focus new cloud native applications liberty 16.0.0.2 version liberty included version 9.0.0.0 liberty 16.0.0.3 adds support new microprofile programming model simplifies cloud native application development using standard java ee technologies flexible access websphere liberty provided additional distributions docker image cloud foundry buildpack september 2017 ibm moved ongoing development liberty new open source project called open liberty open liberty source liberty runtime websphere application server distributions open liberty supported openliberty.io community ibm provides commercial support liberty websphere application server websphere application server v8.5.5 includes significant enhancements liberty profile including support java se 8 full java ee 7 compliance since v8.5.5.6 websphere intelligent management capabilities websphere liberty support java ee enabled configuration sets features different sets library features available edition liberty core edition includes liberty features required java ee webprofile editions add liberty features full java ee 7 network deployment edition adds liberty features intelligent management beyond z/os edition adds liberty features enable z/os platform capabilities websphere application server v8.5 offers java ee 6 java se 6 default v8.0 also provides configured run java se 7 primary new capabilities v8.5 liberty profile websphere application server intelligent management features liberty profile websphere application server included commercial editions server providing lightweight profile server web mobile osgi applications release functional subset full profile websphere application server development production use install size 50 mb startup time around 3 seconds new xml-based server configuration treated development artifact aid developer productivity server capabilities engaged set features defined server configuration features added removed dynamically internal use osgi services new model provided moving applications pipeline development production packaged server complete archive server server configuration application unzip deploy centralized managed install optionally available job manager component websphere application server network deployment edition intelligent management capability added network deployment z/os editions websphere application server integrates operational features previously available separate websphere virtual enterprise wve offering application editioning server health management dynamic clustering intelligent routing compute grid also included network deployment z/os editions websphere application server previously separately priced websphere xd compute grid feature scheduling managing java batch workloads version released september 9 2008 java ee 5 compliant application server following flagship features introduced websphere application server version 7 flexible management facilitates administration large number websphere application server base edition network deployment topologies might geographically distributed business-level application used managing application artifacts independent packaging programming models property based configuration feature simplifies experience automating administration administrator update websphere application server version 7 configuration using simple property file general availability websphere application server v7 websphere application server v8 2011 number additional capabilities made available v7 form feature packs optionally added v7 install feature pack content quality support main release content purpose feature pack deliver new innovation next major release following feature packs provided websphere application server v7 version released june 30 2006 september 11 2012 ibm extended end service v6.1 full year september 30 2013 announced new version-to-version migration incentives assistance java ee 1.4 compliant application server includes following function support ejb 3.0 technology support webservices standards provided ejb feature pack webservices feature packs respectively function feature packs folded main product version 7 functions webservices feature pack include version 6 functionality previously found websphere business integration server foundation wbisf moved new ibm websphere process server function moved editions express version released january 16 2004 j2ee 1.4 compliant application server version released november 19 2002 j2ee 1.3 certified application server major rewrite v3/v4 codebase first time websphere application server coded common codebase across deployment platforms intel x86 mainframe substantially code database-based configuration repository replaced replication xml file-based configuration repository service called deployment manager master copy cell configuration nodes file needed copied master server whenever changed v5 also included miniature version mq 5.3 called embedded java message service jms server j2ee 1.2 certified application server inherited database-based configuration model v3.x single-server edition already used xml datastore websphere 3.5 first widely used version websphere ibm adds javabean corba linux support comes two editions standard edition se advanced edition ae initial release june 1998 primarily java servlet engine websphere application server security model based services provided operating system java ee security model websphere application server provides implementations user authentication authorization mechanisms providing support various user registries authentication mechanisms supported websphere java ee application servers
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Web technology
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prefix whois prefix whois open source project develops operates free whois-compatible framework stockpiling querying various routing registry information prefix whois uses global bgp routing data learned many isp backbone routers information sources also supported imported data every regional internet registry afrinic apnic arin lacnic ripe geocoding information project mentioned number popular network security network engineering books articles many public servers around world operate mirrors prefix whois making information generally available worldwide service may used client using standard whois protocol dns address whois.pwhois.org resolves prefix whois server nearest client based anycast dns several client software packages available prefix whois commercial vendors include free open source utilities whob layer four traceroute prefix whois project distributes c php libraries direct access prefix whois servers http simplequery interface also available software made available custom license
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Computer security
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small subgroup confinement attack cryptography subgroup confinement attack small subgroup confinement attack cryptographic method operates large finite group attacker attempts compromise method forcing key confined unexpectedly small subgroup desired group several methods found vulnerable subgroup confinement attack including forms applications diffie–hellman key exchange dh-eke
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Computer security
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long-term support long-term support lts product lifecycle management policy stable release computer software maintained longer period time standard edition term typically reserved open-source software describes software edition supported months years longer software standard edition short term support sts term distinguishes support policy software standard edition sts software comparatively short life cycle may afforded new features omitted lts edition avoid potentially compromising stability compatibility lts release lts applies tenets reliability engineering software development process software release life cycle long-term support extends period software maintenance also alters type frequency software updates patches reduce risk expense disruption software deployment promoting dependability software necessarily imply technical support beginning long-term support period software developers impose feature freeze make patches correct software bugs vulnerabilities introduce new features may cause regression software maintainer either distributes patches individually packages maintenance releases point releases service packs conclusion support period product either reaches end-of-life receives reduced level support period time e.g. high-priority security patches upgrading software decision-maker might consider risk cost upgrade software developers add new features fix software bugs accidentally introduce new bugs break old functionality flaw occurs software called regression two ways software publisher maintainer reduce risk regression release major updates less frequently allow users test alternate updated version software lts software applies two risk-reduction strategies lts edition software published parallel sts short-term support edition since major updates sts edition published frequently offers lts users preview changes might incorporated lts edition changes judged sufficient quality using older versions software may avoid risks associated upgrading may introduce risk losing support old software long-term support addresses assuring users administrators software maintained specific period time updates selected publication carry significantly reduced risk regression maintainers lts software publish updates either low risk reduce risk security patches patches lts software published understanding installing less risky installing table lists specific lts version addition normal release cycle many projects centos provide long period support every release
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Computer security
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ms-dos editor ms-dos editor commonly called edit edit.com character-based text editor comes ms-dos since version 5 32-bit versions microsoft windows superseded edlin standard editor earlier versions ms-dos 6.22 actually qbasic running editor mode dos 7 windows 95 qbasic removed ms-dos editor became standalone program editor sometimes used substitute notepad windows 9x notepad limited small files editor edit files 65,279 lines approximately 5 mb size ms-dos versions limited approximately depending much conventional memory free editor launched typing run command dialog windows typing codice_1 command-line interface edit still included later versions windows windows xp windows vista 32 bit windows 7 32 bit windows 8 32 bit 16-bit dos application directly run 64-bit windows versions edit version 1.0 appeared ms-dos ibm pc dos 5.00 os/2 windows nt 4.0 early chicago betas included version editors rely qbasic 1.0 version open one file limit dos memory although editor open one file also open quick help file split window edit version 1.1 appeared ms-dos 6.0 new features added editor main difference qbasic 1.1 used show ms-dos 6.0 help version available also versions windows 9x although files unchanged 6.22 renaming help.hlp edit.hlp allows one access dos 6 help system inside editor including cut paste help system open file pc dos 6 include edit command instead dos e editor upgraded support mouse menus version 7.0 edit version 2.0 appeared windows 95 appears windows 2000 later using qbasic still 16-bit dos program included 64-bit version windows directly work one version edit run dos 3.30 higher requires 80286 nec v20/v30 processor higher run 8088 8086 processor cause system stop responding freedos version developed shaun raven licensed gpl ms-dos editor uses text user interface color scheme adjusted multiple document interface version 2.0 included dos 7 windows 9x open 9 files time earlier versions included dos 5 6 limited one file screen split vertically two panes used view two files simultaneously different parts file also open files binary mode fixed number characters displayed per line newlines treated like character mode shows characters hexadecimal characters 0-9 a-f editor converts unix newlines dos newlines mouse support features added 1995 version 2.0 release windows 95
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Computer architecture
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vivaldi web browser vivaldi freeware cross-platform web browser developed vivaldi technologies company founded opera software co-founder former ceo jon stephenson von tetzchner tatsuki tomita officially launched april 6 2016 although intended general users first foremost targeted towards technically-inclined users well former opera users disgruntled transition presto layout engine chromium-based browser resulted loss many iconic features despite also chromium-based vivaldi aims revive features presto-based opera proprietary modifications march 2019 vivaldi 1.2 million active monthly users vivaldi began virtual community website replaced opera shut opera software march 2014 jon stephenson von tetzchner angered decision believed community helped make opera web browser tetzchner launched vivaldi community—a virtual community focused providing registered users discussion forum blogging service numerous practical web services—to make opera closure later january 27 2015 vivaldi technologies launched—with community mind—the first technical preview vivaldi web browser name comes italian composer antonio vivaldi according one creators easy name remembered understood worldwide vivaldi minimalistic user interface basic icons fonts color scheme changes based background design web page visited browser also allows users customize appearance ui elements background color overall theme address bar tab positioning start pages according ceo jon von tetzchner vivaldi vast unique customizability huge part browser caters experienced users vivaldi features ability stack tile tabs annotate web pages add notes bookmarks furthermore users place digital bookmarks speed dial page quick access harness quick commands search bookmarks browsing history open tabs settings vivaldi built around based web technologies html5 node.js react.js numerous npm modules technical preview 4 vivaldi also supports numerous mouse gestures actions like tab switching keyboard activation vivaldi also set chromeless ui gives users screen real-estate ability focus single page without distractions accommodate users prefer use large number tabs time vivaldi supports hibernation individual tabs tab stacks freeing resources user actively use tabs chromium-based browser vivaldi use many browser extensions developed google chrome users install directly chrome web store work properly vivaldi exception user interface customizations vivaldi interface quite different chrome company hopes integrate email client m3 future version vivaldi developers planning release extension platform vivaldi statcounter estimates vivaldi 0.05 market share desktop browsers december 2018 ars technica reviewer scott gilbertson wrote version 1.0 april 2016 praised innovative features tab handling noting likely remain niche browser see widespread uptake october 2018 gilbertson gave version 2.0 positive review stated vivaldi usual browser would hard put go back browser without unique features
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Internet protocols
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physical information security physical information security intersection common ground physical security information security primarily concerns protection tangible information-related assets computer systems storage media physical real-world threats unauthorized physical access theft fire flood typically involves physical controls protective barriers locks uninterruptible power supplies shredders information security controls physical domain complement logical domain encryption procedural administrative controls information security awareness compliance policies laws asset inherently valuable yet vulnerable wide variety threats malicious e.g theft arson accidental/natural e.g lost property bush fire threats materialize exploit vulnerabilities causing incidents likely adverse impacts organizations individuals legitimately utilize assets varying trivial devastating effect security controls intended reduce probability frequency occurrence and/or severity impacts arising incidents thus protecting value assets physical security involves use controls smoke detectors fire alarms extinguishers along related laws regulations policies procedures concerning use barriers fences walls doors obvious physical security controls designed deter prevent unauthorized physical access controlled area home office moats battlements mediaeval castles classic examples physical access controls bank vaults safes information security controls protect value information assets particularly information i.e intangible information content data intellectual property knowledge etc also computer telecommunications equipment storage media including papers digital media cables tangible information-related assets computer power supplies corporate mantra people greatest assets literally true sense so-called knowledge workers qualify extremely valuable perhaps irreplaceable information assets health safety measures even medical practice could therefore also classed physical information security controls since protect humans injuries diseases death perspective exemplifies ubiquity value information modern human society heavily reliant information information importance value deeper fundamental level principle subcellular biochemical mechanisms maintain accuracy dna replication could even classed vital information security controls given genes 'the information life malicious actors may benefit physical access information assets include computer crackers corporate spies fraudsters value information assets self-evident case say stolen laptops servers sold-on cash information content often far valuable example encryption keys passwords used gain access systems information trade secrets intellectual property inherently valuable valuable commercial advantages confer credit card numbers used commit identity fraud theft furthermore loss theft damage computer systems plus power interruptions mechanical/electronic failures physical incidents prevent used typically causing disruption consequential costs losses unauthorized disclosure confidential information even coercive threat disclosure damaging saw sony pictures entertainment hack end 2014 numerous privacy breach incidents even absence evidence disclosed personal information actually exploited fact longer secured control rightful owners potentially harmful privacy impact substantial fines adverse publicity/reputational damage noncompliance penalties impacts flow serious privacy breaches best avoided regardless cause several ways obtain information physical attacks exploitations examples described dumpster diving practice searching trash hope obtaining something valuable information carelessly discarded paper computer disks hardware sometimes attackers simply go building take information need frequently using strategy attacker masquerade someone belongs situation may pose copy room employee remove document someone desk copy document replace original leave copied document individuals pretending building maintenance may gain access otherwise restricted spaces might walk right building trash bag containing sensitive documents carrying portable devices storage media left desks perhaps memorized password sticky note stuck someone computer screen called colleague across open office literally shredding paper documents prior disposal commonplace physical information security control intended prevent information content media falling wrong hands digital data also shredded figurative sense either strongly encrypted repeatedly overwritten realistic probability information ever retrieved even using sophisticated forensic analysis constitutes physical information security control since purged computer storage media freely discarded sold without compromising original information content two techniques may combined high-security situations digital shredding data content followed physical shredding incineration destroy storage media many organizations restrict physical access controlled areas offices requiring people present valid identification cards proximity passes physical keys provided access tokens devices strictly controlled secure making hard unauthorized people obtain fabricate use associated electronic mechanical locks doors walls barriers etc sufficiently strong complete unauthorized physical entry controlled areas prevented protecting information assets within likewise office workers generally encouraged required obey clear desk policies protecting documents storage media including portable devices tidying away sight perhaps locked drawers filing cabinets safes vaults according risks requiring workers memorize passwords rather writing place might observed onlooker maybe colleague visitor intruder example risk avoidance computers plainly need electrical power hence vulnerable issues power cuts accidental disconnection flat batteries brown-outs surges spikes electrical interference electronic failures physical information security controls address associated risks include fuses no-break battery-backed power supplies electrical generators redundant power sources cabling remove warning signs plugs surge protectors power quality monitoring spare batteries professional design installation power circuits plus regular inspections/tests preventive maintenance ironic so-called uninterruptible power supplies often lead power interruptions inadequately specified designed manufactured used managed maintained illustration failure critical physical control
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Computer security
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westmere microarchitecture westmere formerly nehalem-c code name given 32 nm die shrink nehalem sharing cpu sockets westmere included intel hd uhd iris graphics nehalem first westmere -based processors launched january 7 2010 intel corporation westmere architecture available intel brands core i3 core i5 core i7 pentium celeron xeon westmere feature improvements nehalem reported successor nehalem westmere sandy bridge
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Computer architecture
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printer driver computers printer driver print processor piece software computer converts data printed format printer understand purpose printer drivers allow applications printing without aware technical details printer model printer drivers confused print spoolers queue print jobs send successively printer unix unix-like systems linux os x use cups short common unix printing system modular printing system unix-like computer operating systems allows computer act print server computer running cups host accept print jobs client computers process send appropriate printer printer drivers typically implemented filters usually named front end printing system printer spoolers constitute back end backends also used determine available devices startup backend asked list devices supports information available dos supports predefined character devices codice_1 codice_1 codice_1 codice_1 associated parallel printers supported system similarly serial printers used codice_1 codice_1 codice_1 codice_1 codice_1 users use commands like example codice_10 print content file printer contents transferred printer without interpretation therefore method printing either files already stored corresponding printer language generic text files without simple line-oriented formatting dos also provides dynamically loadable print spooler named print well optional support support screen captures also graphics mode graphics optional character device driver printer.sys loaded dos provides code page switching support also associated printers—different types dot matrix ink jet printers supported default beyond system-wide printer-specific drivers use application level ms-dos/pc dos dr-dos however script command loaded run background order intercept convert printer output applications postscript support ps-capable printers also applications supporting directly order support complex printing different models printers application e.g word processor may shipped printer drivers essentially descriptions printer escape sequences printers supplied drivers popular applications addition possible applications include tools editing printer description case ready driver days dos widely used many printers emulation modes epson fx-80 ibm proprinter commands many recent laser printers also emulation modes hp pcl hp laserjet postscript printers work dos appears also compatible windows 3.x microsoft windows systems printer drivers make use gdi unidrv pscript-based xps xpsdrv programs use standard apis draw text pictures screen paper printers use gdi natively commonly referred winprinters considered incompatible operating systems although software printfil make printers work dos prompt within windows win32 apis also allow applications send data directly spooler bypassing printer driver however applications actually use option printer driver usually located c \windows\system32\driverstore\filerepository folder windows machine original amigaos 1.3 supported printers standard series drivers stored required path devs printers printer drivers stored directory covered standard printers 1985-1989 circa included epson fx standard driver xerox 4020 hp etcetera amiga printer driver communicate though standard amiga printer.device default standard hardware device amiga dealing printers standard parallel.device controlled parallel port driver would control printer amiga printer drivers innovation time spared users individually configuring applications ability print 4096 colors use printer preferences program printers could connected serial port well amiga also support virtual device prt refer printer.device example command copy file prt caused file printed directly bypassing parallel.device default printer driver amiga used ansi escape codes special ones defined various printer manufacturers way every application amiga could use standard set control sequences would n't need know printer actually connected printer driver translated standard sequences special sequences certain printer understands amiga internal function pwrite printer.device writes 'length bytes directly printer function generally called printer drivers send buffer printer number buffers decided persons created driver amiga lacked standard printer spooler since amigaos 2.0 standard printer.device changed control various printers time printer preferences divided three main panels prefs printer selects main printer basic elements print spacing paper size printergfx controlled features like dithering scaling printerps controlled postscript printers printer drivers surprisingly remained almost workbench 1.3 4096 limits fact led amiga users prefer third party printer systems drivers like turboprint printstudio introduced recent drivers also featured functioning printer spooler amiga featured 16 millions colors printing morphos uses special version turboprint pilot recent printers many amiga programs like dtp programs pagestream featured past printer drivers usb printers automatically recognized poseidon usb stack stack capable detecting usb device class printers still require driver controlled addition install-able computer drivers could also present embedded firmware printers made available networking protocol e.g ipp embedded firmware printer could thus eliminate need install driver computer accepting print data general purpose format e.g pdf via networking protocol despite efforts standardize various stages printing pipeline printer interfaces largely still proprietary manufacturer-specific hence nature functions performed drivers vary nonetheless based function performed drivers classified follows drivers convert print data one general purpose format e.g pdf dvi etc another general purpose format e.g ps examples include ghostscript etc drivers convert print data one format e.g ps final device-specific format printer hardware process create print drivers act last stage delivering print job printer drivers likely embedded printer firmware examples manufacturer specific formats include install-able drivers packaged various formats ppd popular packaging format drivers accept postscript data pdf data input due dominance select operating systems operating system–driver interface standardized driver–printer interfaces hence standardization packaging formats drivers actual functions performed drivers
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Operating systems
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ntfs-3g ntfs-3g open-source cross-platform implementation microsoft windows ntfs file system read-write support ntfs-3g often uses fuse file system interface run unmodified many different operating systems runnable linux freebsd netbsd opensolaris illumos beos qnx wince nucleus vxworks haiku morphos minix macos openbsd licensed either gnu general public license proprietary license partial fork ntfsprogs active maintenance development ntfs-3g introduced one senior linux ntfs developers szabolcs szakacsits july 2006 first stable version released 2007-02-21 version 1.0 developers ntfs-3g later formed company tuxera inc. develop code ntfs-3g free community edition tuxera ntfs proprietary version ntfs-3g supports operations writing files files size created modified renamed moved deleted ntfs partitions transparent compression supported well system-level encryption support modify access control lists permissions available ntfs partitions mounted using filesystem userspace fuse interface according man page ntfs-3g supports hard links symbolic links ntfs-3g supports partial ntfs journaling unexpected computer failure leaves file system inconsistent state volume repaired 2009 volume unclean journal file recovered mounted default ‘ norecover ’ mount option used disable behavior benchmarks show driver performance via fuse comparable filesystems drivers in-kernel provided cpu powerful enough embedded old systems high processor usage severely limit performance
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Computer file systems
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system v printing system printing subsystem unix system v one several standardized systems printing unix typical commercial system v-based unix versions solaris sco openserver system running print architecture could traditionally identified use user command primary interface print system opposed bsd command though systems provide alias typical user commands available system v printing system unix programming model device files special files act access points peripheral devices printers example first line printer unix system might represented file device directory i.e using file metaphor document could printed copying file onto device worked well enough case one printer per user model scale well multiple users share one printer solution create queue spool documents printed use daemon system process manage queue send documents printer order arrived system command send documents queue first introduced 1973 version 4 unix release system v release 4 suite utilities grown include commands canceling print jobs moving jobs among queues enabling disabling queues enabling disabling job scheduler daemon status reports print system command handled queue documents printed 20 different options controlled appearance document place queue even handled email notification user document finished printing command returned job id could used cancel lpstat commands remove job queue check progress respectively system considered quite complex set administer uses expected use three commands distribution influential unix system v interface implementation became standard users control printers command included requirement posix.2 standard command name appeared subsequent lpr lprng cups printing systems svr4 derivates like sco unix command simply alias command used bsd-based system late 1996 running linux stated linux printing software consists unix standard lp lpr software 1999 support lp waning third edition simply stated lpr command prints document linux 2003 survey debian mandrake red hat slackware suse distributions showed running combination lpr lprng cups original system v printing system remains proprietary however solaris print system heavily modified original released open source software part opensolaris project common unix printing system emulates system v berkeley print architectures interface level though internal architecture different introduction simplified configuration system lp author peter gray university wollongong described several weaknesses version shipping then-current solaris operating system version 2 result gray observed many administrators choose simply run old lpr/lpd system svr4 boxes
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Operating systems
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macintosh quadra 700 macintosh quadra 700 personal computer designed manufactured sold apple computer inc. october 1991 march 1993 introduced alongside quadra 900 first computers quadra series using motorola 68040 processor also first computer apple housed mini-tower form factor 1991 becoming popular alternative standard desktop-on-monitor cases common 1980s quadra 700 originally list price 5,700 usd dropped 4,700 base model time replacement macintosh quadra 800 went sale early 1993 centris 650 also introduced around time offered incrementally performance quadra 700 desktop-style case price point closer 3,000 form factor quadra 700 case largely popular macintosh iicx macintosh iici models made possible users models upgrade powerful quadra 700 users sometimes placed older case vertically mini-tower orientation quadra 700 recognized apple logo model name printed vertical orientation iicx iici designed allow rubber feet moved side vertical orientation well cpu motorola 68040 25 mhz clock oscillator runs 50 mhz replacing faster oscillator 74 mhz results performance increase memory quadra 700 could upgraded 68 megabytes ram 25 mhz processor made useful computer scientific design work expansion two nubus slots pds slot processor upgrades apple manufacturers sold 700 powerpc 601 accelerator cards came along 1994 storage 80 160 mb hard disks available launch faster 230 mb unit became available mid-1993 quadra 950 introduced video like iici 700 integrated graphics built system board unlike earlier model uses dedicated vram video memory onboard video came 512 kilobytes vram soldered motherboard supported resolutions 1152x870 video memory expandable 2 megabytes via 6 256-kilobyte 100 ns vram simms vram simm expansion slots motherboard expanding video memory 2 megabytes allowed 24-bit millions color resolutions 832x624 sound sound 8-bit stereo ports i/o available dual serial ports aaui ethernet port mic db-25 scsi connector quadra 700 along 900 first macintosh models built-in support ethernet networking operating system system 7.0.1 included standard earliest macintosh model support mac os 8
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Computer architecture
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usage share operating systems usage share operating systems percentage computing devices run operating system particular time figures necessarily estimates data operating system share difficult obtain reliable primary sources agreed methodologies collection personal computing platform area smartphones watches google android dominates 2.5 billion users mobile phone operating systems include apple ios kaios series 30+ area desktop laptop computers microsoft windows generally 70 markets 78 globally apple macos around 14 google chromeos 3 north america linux around 2 figures vary somewhat different markets depending gathered android battling windows used rank often popular past global scale ios never managed close half popularity windows however mobile operating systems android plus ios majority use non-mobile windows e.g macos close two years mostly android continues popular windows still countries continents mobile devices never anywhere near popular continents countries become mobile-majority still including ireland ios alone popular windows later android alone europe populous countries populous continent asia whole e.g china india excluding e.g russia still mobile-majority 56.37 public internet servers linux generally counted dominant powering twice number hosts windows server trailed many smaller players including traditional mainframe oses supercomputer field completely dominated linux 100 top500 running os according gartner following worldwide device shipments referring wholesale operating system includes smartphones tablets laptops pcs together shipments stores mean sales consumers necessarily year shipment therefore suggesting numbers indicate popularity and/or usage could misleading smartphones sell higher numbers traditional pcs also whole lot dollar value gap projected widen well double 2015 earlier gartner reports year worldwide pc shipments declined fourth consecutive year started 2012 launch tablets 8 decline pc sales 2015 including cumulative decline sales previous years gartner includes macs running macos pc sales numbers e.g ipads androids individually slight increase sales 2015 28 may 2015 google announced 1.4 billion android users 1 billion google play users active month changed 2 billion monthly active users may 2017 27 january 2016 paul thurrott summarized operating system market day apple announced one billion devices microsoft backed away goal one billion windows 10 devices three years middle 2018 reported 26 september 2016 windows 10 running 400 million devices march 2019 800 million late 2016 android e.g samsung smartphones explained killing apple ios market share i.e declining sales smartphones relatively also number units whole market increasing 9 may 2019 biggest smartphone companies market share samsung huawei apple respectively gartner press release said apple continued downward trend decline 7.7 percent second quarter 2016 decline based absolute number units underestimates relative decline market increasing along misleading 1.7 percent point decline point decline means 11.6 relative decline 14.6 12.9 although units sold apple declining almost vendor making profit smartphone sector hardware sales alone q3 2016 example captured 103.6 market profits mobile phone owners toothbrush owners mobile phones fastest growing technology history billion active mobile phones world people many 10 billion sold far less half still use explained fact people one extra work phones operating system fraction smartphones os capable running modern applications currently 3.1 billion smartphones tablets use across world tablets small fraction total generally running operating systems android ios latter popular tablets 2019 announced variant ios called ipados specifically ipad tablets development 2015 emarketer estimated beginning year tablet installed base would hit one billion first time china use 328 million google play n't serve track usa use second 156 million end year cheap tablets counted analysts goal met even excluding cumulative sales previous years conflicts statistics idc say tablet market contracted 10 2015 huawei ranked fifth big gains doubling share fourth quarter 2015 five biggest vendors except amazon fire tablets ranked third worldwide new list enabled quite tripling market share 7.9 fire os android-derivative recent data various sources published last twelve months summarized table sources monitor substantial number web sites statistics related one web site excluded android currently ranks highest windows incl xbox console systems every day week ios competes windows sweden depending day ios used ios windows 10 competing 13 windows mobile systems i.e windows phone accounts 0.51 web usage weekends ios alone topped windows us ios n't popular independent country guam unincorporated territory united states three consecutive quarters ios also highest ranked falkland islands british overseas territory one quarter plus one month overtaken android following quarter unknown strangely high countries madagascar 32.44 may due fact statcounter uses browser detection get os statistics common browsers often used version breakdown browsers madagascar shows 34.9 opera mini 4.4 popular known browser 22.1 plus e.g 3.34 opera 7.6 however browser statistics without version-breakdown opera 48.11 category small china android highest ranked operating system since january 2016 windows occasionally topped since asian continent whole android ranked highest since february 2016 android alone majority share large majority populous countries continent 84 bangladesh since august 2015 android ranked first 48.36 may 2016 african continent took big jump ahead windows 7 thereby africa joined asia mobile-majority continent china longer desktop-majority country joining india mobile-majority 71 confirming asia significant mobile-majority online usage linux kernel derivatives google systems gnu/linux exceeds windows true since time january april 2016 according w3counter statcounter however even figure unix-like oses including apple higher windows windows still dominant desktop os dominance varies region gradually lost market share desktop operating systems mobile slide noticeable us macos usage tripled 2009 2017 windows 72.76 chrome os 3.33 plus traditional linux 1.46 little openly published information device shipments desktop laptop computers gartner publishes estimates way estimates calculated openly published another source market share various operating systems statcounter basing estimate web use although may accurate also sales may overstate usage computers sold pre-installed operating system users replacing os different one due personal preference installing another os alongside using conversely sales underestimate usage counting unauthorized copies example 2009 approximately 80 software sold china comprised illegitimate copies 2007 statistics automated update ie7 registered windows computers differed observed web browser share leading one writer estimate 25–35 windows xp installations unlicensed usage share microsoft latest client operating system windows 10 slowly increasing since july/august 2016 windows 7 slight decrease time reaching around 27.15 december 2016 web analysis shows significant variation different parts world example north america usage windows xp dropped 2.06 africa still 11.02 asia 6.63 even higher china 18.21 tied windows 10 second going overtaken windows 10 conversely macos north america claims 16.82 17.52 us whereas asia 4.4 2019 stack overflow developer survey provides detail particular versions windows desktop operating system share among identifying professional developers june 2016 microsoft claimed windows 10 half market share windows installations usa uk quoted betanews digital video game distribution platform steam publishes monthly hardware software survey statistics q1 2018 mobile operating systems smartphones included google dominant android variants apple ios combined almost 100 market share smartphone penetration vs. desktop use differs substantially country countries like russia still smartphone use low 19 western countries smartphone use close 50 smartphone usage share developing countries much higher bangladesh example android smartphones 84 share mali smartphones 90 95 share year section information regional trends move smartphones clear correlation gdp per capita country country respective smartphone os market share richest countries much likely choose apple iphone google android predominant elsewhere tablet computers simply tablets became significant os market share category starting apple ipad q1 2018 ios 65.03 market share android 34.58 market share windows tablets may get classified analysts thus barely register e.g 2-in-1 pcs may get classified desktops tablets since 2016 south america cuba north america android tablets gained majority asia 2017 android slightly popular ipad 49.05 usage share october 2015 africa android tablets much popular elsewhere ipad safe margin android made steady gains becoming popular tablet operating system trend many countries already gained majority large countries india 63.25 indonesia 62.22 african continent android 62.22 first gain android majority late 2014 steady gains 20.98 august 2012 egypt 62.37 zimbabwe 62.04 south america 51.09 july 2015 peru 52.96 asia 46 nepal android gained majority lead november 2014 lost 41.35 ios 56.51 taiwan october 2016 android gained confident majority losing streak china major exception android gaining market share asia android phablets much popular android tablets similar devices get classified smartphones ipad/ios 82.84 march 2015 according statcounter web use statistics proxy use smartphones popular desktop computers globally android particular popular windows although desktop computers still popular many countries overall 44.9 first quarter 2017 smartphones popular even many developed countries countries continents desktop-minority android popular windows many e.g poland europe half countries south america many north america e.g guatemala honduras haiti countries asia africa smartphone-majority android poland turkey europe highest 57.68 62.33 respectively ireland smartphone use 45.55 outnumbers desktop use mobile whole gains majority including tablet share 9.12 spain also slightly desktop-minority july 2019 sweden desktop-minority eight weeks row range measured mobile web use varies lot country statcounter press release recognizes india amongst world leaders use mobile surf internet big countries share around 80 desktop 19.56 russia trailing 17.8 mobile use desktop rest smartphones discounting tablets first gained majority december 2016 desktop-majority lost month n't christmas-time fluke close majority smartphone majority happened march 2017 week 7–13 november 2016 smartphones alone without tablets overtook desktop first time albeit short period examples mobile-majority countries include paraguay south america poland europe turkey asia africa world still desktop-majority example united states 54.89 days however territories united states puerto rico desktop significantly majority windows 30 overtaken android 22 october 2016 subsequent weekends mobile showed majority since 27 october desktop n't majority including weekdays smartphones alone showed majority since 23 december end year share topping 58.22 christmas day mobile -majority share smartphones tablets could added giving 63.22 majority unusually high top similar high also occurred monday 17 april 2017 smartphone share slightly lower tablet share slightly higher combining 62.88 formerly according statcounter press release world turned desktop-minority 49 desktop use month mobile n't ranked higher tablet share added exceed desktop share christmas season i.e temporarily desktop-minority remains smartphone-majority weekends last two weeks december 2016 australia oceania general desktop-minority first time extended period i.e every day 23 december south america smartphones alone took majority desktops christmas day full-week-average desktop still least 58 uk desktop-minority dropped 44.02 christmas day eight days end year ireland joined european countries smartphone-majority three days christmas topping day 55.39 us desktop-minority happened three days around christmas longer four-day stretch happened november happens frequently weekends according statcounter web use statistics proxy use week 7–13 november 2016 mobile meaning smartphones alone without tablets overtook desktop first time highest ranked 52.13 27 november 2016 49.02 full week mobile-majority applies countries paraguay south america poland europe turkey continents asia africa large regions rest world still desktop-majority days united states north america whole n't us desktop-minority four days row five-day average examples desktop-minority days include uk ireland australia oceania whole fact least one country every continent turned desktop-minority least month 22 october 2016 subsequent weekends mobile shown majority previously according statcounter press release world turned desktop-minority 49 desktop use month desktop-minority stretching 18-weeks/4-months period 28 june 31 october 2016 whole july august september 2016 showed desktop-majority many long sub-periods long stretch showed desktop-minority similarly fridays saturdays sundays desktop-minority biggest continents asia africa shown vast mobile-majority long time day week well several individual countries elsewhere also turned mobile-majority poland albania turkey europe paraguay bolivia south america according statcounter web use statistics saturday 28 may 2016 day smartphones mobile statcounter counts tablets separately became used platform ranking first 47.27 desktops next day desktops slightly outnumbered mobile unless counting tablets analysts count tablets smartphones separately others desktops even tablets ipad android windows devices since sunday 27 march 2016 first day world dipped desktop-minority happened almost every week week 11–17 july 2016 world desktop-minority followed next week thereon also three-week period trend still stronger weekends e.g 17 july 2016 showed desktop 44.67 mobile 49.5 plus tablets 5.7 recent weekly data shows downward trend desktops according statcounter web use statistics proxy overall use weekends desktops worldwide lose 5 percent points e.g 51.46 15 august 2015 loss relative web use going mobile also minuscule increase tablets mostly windows 7 ranked 1st workdays declines web use shifting android lesser degree ios two continents already crossed mobile-majority android based statcounters web use statistics june 2015 asia became first continent mobile overtook desktop followed africa august nigeria mobile majority october 2011 symbian later 51 share series 40 dominating followed android dominating operating system far back october 2014 reported trend large scale press release mobile usage already overtaken desktop several countries including india south africa saudi arabia india desktop went majority july 2012 32 bangladesh desktop went majority may 2013 17 android alone accounting majority web use african countries still desktop-majority many large mobile majority including ethiopia kenya mobile usage 72 popularity mobile use worldwide driven huge popularity increase android asian countries android highest ranked operating system statistically virtually every south-east asian country also ranks popular almost every african country poland desktop-minority since april 2015 android vastly popular european countries albania turkey also crossed south america continent somewhat far losing desktop-majority paraguay lost android mobile browsing general also become hugely popular continents desktop large desktop base trend mobile clear fraction total web use analysts count tablets desktops run windows others count mobile phones vast majority tablets run so-called mobile operating system android operating system |android ios ipad ipad clear lead globally clearly lost majority android south america number eastern european countries poland lost virtually african countries lost majority twice asia gained majority back many individual countries e.g india middle east clear android majority tablets android tablets thus second popular ipad march 2015 first time us number mobile-only adult internet users exceeded number desktop-only internet users 11.6 digital population using mobile compared 10.6 using desktop also means majority 78 use desktop mobile access internet smaller countries north america haiti android gone mobile majority mobile went 72.35 64.43 february 2016 region largest android usage also largest mobile revenue file rack001.jpg|thumb| server computing |servers colocation centre |upright|right server computing |internet based servers market share measured statistical surveys publicly accessible servers web server mail server dns server internet operating systems powering servers found inspecting raw response messages method gives insight market share operating systems publicly accessible internet differences result depending sample done observations weighted usually surveys based random sample ip numbers domain names hosts organisations servers found method additionally many domains ip numbers may served one host domains may served several hosts one host several ip numbers file ibm system z10.jpg|thumb|upright|right|ibm ibm system z10|system z10 common operating system mainframes ibm z/os operating systems ibm system z generation hardware include ibm proprietary z/os linux z systems transaction processing facility|z/tpf vse operating system |z/vse z/vm gartner reported 23 december 2008 linux system z used approximately 28 customer z base expected increase 50 following five years linux system z red hat micro focus compete sell red hat enterprise linux|rhel suse linux enterprise server|sles respectively file operating systems used top 500 supercomputers.svg|thumb|upright=1.8|supercomputer os family 1993–2019 systems share according top500 field supercomputers always dominated unix unix-like operating systems linux predominating since 2017 top 500 fastest supercomputers run linux top500 project lists ranks 500 fastest supercomputer benchmark results submitted june 2017 two aix computers held rank 493 494 last non-linux systems dropped list last non-linux fastest supercomputer asci white also running aix held title november 2000 november 2001 decommissioned 2006 historically kinds unix operating systems dominated end ultimately linux remains category operating systems|*usage share operating systems category usage share|operating systems
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Operating systems
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search/retrieve via url search/retrieve via url sru standard search protocol internet search queries utilizing contextual query language cql standard query syntax representing queries sample code complete answer sru query-url url query version=1.1 operation=searchretrieve query=dc.title=darwinism cql query dc.title=darwinism
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Web technology
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gauss software gauss matrix programming language mathematics statistics developed marketed aptech systems primary purpose solution numerical problems statistics econometrics time-series optimization 2d- 3d-visualization first published 1984 ms-dos currently also available linux macos windows range toolboxes available gauss additional cost see https //www.aptech.com/products/gauss-applications/ complete listing products
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Programming language topics
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element anti-virus solution9 formerly known element anti-virus antivirus software personal firewall package made software house strayspark lab formerly element software uk llc element anti-virus aimed primarily home use microsoft windows operating systems version 6.0 2012 feature known collective intelligence introduced product use back-end server technology known element software network esnet technology enabled product collects suspicious files sends statistics using md5 patterns central database reviewed commonly due privacy concerns however disabled default technology 'trace made malware origins flag commonly found malicious software client machine via world map version 6.0 2012 personal firewall solution network topology analysis software introduced product along packet tracer analyzer administrative use confirmed company twitter account re-launched website solution9 strayspark replacing element anti-virus one first antimalware solutions use hypervisor means security real operating environment
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Computer security
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transient-key cryptography transient-key cryptography form public-key cryptography wherein keypairs generated assigned brief intervals time instead individuals organizations blocks cryptographic data chained time transient-key system private keys used briefly destroyed sometimes nicknamed “ disposable crypto. ” data encrypted private key associated specific time interval irrefutably linked interval making transient-key cryptography particularly useful digital trusted timestamping public-key transient-key systems used generate digital signatures assert given piece data changed since signed similarities end traditional public key system public/private keypair typically assigned individual server organization data signed private key asserts signature came indicated source keypairs persist years time private component must carefully guarded disclosure public-key system anyone access private key counterfeit person digital signature transient-key systems however keypair assigned brief interval time particular person entity data signed specific private key becomes associated specific time date keypair active minutes private key permanently destroyed therefore unlike public-key systems transient-key systems depend upon long-term security private keys transient-key system source time must consistent standard understood senders receivers since local system clock may changed user never used source time instead data digitally signed time value derived universal coordinated time utc accurate within millisecond accordance ansi asc x9.95 standard trusted timestamping whenever time interval transient-key system expires new public/private keypair generated private key previous interval used digitally certify new public key old private key destroyed key-chaining system immediate ancestor blockchain technology vogue today new interval time values obtained trusted third-party source specific moments time interpolated received times using time-biasing method based internal system timer trusted time source obtained running within specified tolerances transient private keys issued case time interval chain terminated fresh one begun old new chains connected network archives enable servers continue verify data integrity time protected data regardless often chain must restarted start times chain interval coupled together form unbroken sequence public keys used following extra security measure requests signatures made interval stored log concatenated appended public key start next interval mechanism makes impossible insert new “ signed events ” interval chain fact independently operating servers cross-certification provide third-party proof validity time interval chain irrefutable evidence consensus current time transient-key cryptographic systems display high byzantine fault tolerance web interconnected cross-certifying servers distributed environment creates widely witnessed chain trust strong strongest link contrast entire hierarchies traditional public key systems compromised single private key exposed individual transient key interval chain cross-certified transient key chains server instances cross-certification server signs server b interval chain signed data interval definition effect private keys server b used sign public keys server diagram server instance cross-certified two server instances blue orange cross-certification requires timestamp interval agree timestamp cross-certifying server within acceptable tolerances user-defined typically hundred milliseconds duration along intervals cross-certifications stored network archive within transient-key network archive logical database stored replicated system enable verification data timestamped signed transient keys map set accessible archives stored within every digital signature created system whenever cross-certifications completed beginning interval archive map updated published servers network interval transient private key used sign data concatenated trusted timestamps authenticity certificates verify data later time receiver accesses persistent public key appropriate time interval public key applied digital signature passed published cryptographic routines unpack hash original data compared fresh hash stored data verify data integrity signature successfully decrypts using particular interval published public key receiver assured signature originated time period decrypted fresh hashes match receiver assured data tampered since transient private key created timestamp signed data transient-key cryptography invented 1997 dr. michael d. doyle eolas technologies inc. later acquired productized proofspace inc protected us patents 6,381,696 7,017,046 7,047,415 7,210,035 included ansi asc x9.95 standard trusted timestamping transient-key cryptography predecessor forward secrecy despite appearance bitcoin blockchain technology derived transient-key cryptography dr. doyle publicly denied satoshi nakamoto
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Computer security
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streaming text oriented messaging protocol simple streaming text oriented message protocol stomp formerly known ttmp simple text-based protocol designed working message-oriented middleware mom provides interoperable wire format allows stomp clients talk message broker supporting protocol protocol broadly similar http works tcp using following commands communication client server frame consisting number lines first line contains command followed headers form key value one per line followed blank line body content ending null character communication server client message receipt error frame similar format headers body content mom products support stomp list implementations also maintained stomp web site
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Internet protocols
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rainbow table rainbow table precomputed table reversing cryptographic hash functions usually cracking password hashes tables usually used recovering password credit card numbers etc certain length consisting limited set characters practical example space–time tradeoff using less computer processing time storage brute-force attack calculates hash every attempt processing time less storage simple lookup table one entry per hash use key derivation function employs salt makes attack infeasible rainbow tables invented philippe oechslin application earlier simpler algorithm martin hellman computer system requires password authentication must contain database passwords either hashed plaintext various methods password storage exist tables vulnerable theft storing plaintext password dangerous databases therefore store cryptographic hash user password database system one – including authentication system – determine user password merely looking value stored database instead user enters password authentication system computes hash value provided password hash value compared stored hash user authentication successful two hashes match gathering password hash using said hash password would fail since authentication system would hash second time learn user password password produces hashed value must found usually brute-force dictionary attack rainbow tables one type tool developed derive password looking hashed value rainbow tables always needed straightforward methods hash reversal available brute-force attacks dictionary attacks straightforward methods available however adequate systems use long passwords difficulty storing options available searching extensive database perform reverse lookup hash address issue scale reverse lookup tables generated stored smaller selection hashes reversed could make long chains passwords although reverse lookup hash chained table takes computational time lookup table much smaller hashes longer passwords stored rainbow tables refinement chaining technique provide solution problem called chain collisions source suppose password hash function h finite set passwords p. goal precompute data structure given output h hash function either locate element p p h p h determine p p. simplest way compute h p p p storing table requires θ |p| n bits space n size output h prohibitive large |p| hash chains technique decreasing space requirement idea define reduction function r maps hash values back values p. note however reduction function actually inverse hash function rather different function swapped domain codomain hash function alternating hash function reduction function chains alternating passwords hash values formed example p set lowercase alphabetic 6-character passwords hash values 32 bits long chain might look like requirement reduction function able return plain text value specific size generate table choose random set initial passwords p compute chains fixed length k one store first last password chain first password called starting point last one called endpoint example chain aaaaaa would starting point kiebgt would endpoint none passwords hash values would stored given hash value h want invert find corresponding password compute chain starting h applying r h r point observe value matching one endpoints table get corresponding starting point use recreate chain good chance chain contain value h immediately preceding value chain password p seek example 're given hash would compute chain first applying r since one endpoints table take corresponding starting password follow chain 920ecf10 reached thus password different password hash value note however chain always contain hash value h may happen chain starting h merges chain different starting point example may given hash value fb107e70 follow chain get kiebgt chain starting aaaaaa called false alarm case ignore match continue extend chain h looking another match chain h gets extended length k good matches password never produced chains table content depend hash value inverted created repeatedly used lookups unmodified increasing length chain decreases size table also increases time required perform lookups time-memory trade-off rainbow table simple case one-item chains lookup fast table big chains get longer lookup slows table size goes simple hash chains several flaws serious point two chains collide produce value merge consequently table cover many passwords despite paid computational cost generate previous chains stored entirety impossible detect efficiently example third value chain 3 matches second value chain 7 two chains cover almost sequence values final values hash function h unlikely produce collisions usually considered important security feature reduction function r need correctly cover likely plaintexts collision resistant difficulties result importance choosing correct function r. picking r identity little better brute force approach attacker good idea likely plaintexts choose function r makes sure time space used likely plaintexts entire space possible passwords effect r shepherds results prior hash calculations back likely plaintexts benefit comes drawback r likely wo n't produce every possible plaintext class attacker wishes check denying certainty attacker passwords came chosen class also difficult design function r match expected distribution plaintexts rainbow tables effectively solve problem collisions ordinary hash chains replacing single reduction function r sequence related reduction functions r r. way two chains collide merge must hit value iteration consequently final values chain identical final postprocessing pass sort chains table remove duplicate chains final value chains new chains generated fill table chains collision-free may overlap briefly merge drastically reducing overall number collisions using sequences reduction functions changes lookup done hash value interest may found location chain necessary generate k different chains first chain assumes hash value last hash position applies r next chain assumes hash value second-to-last hash position applies r h r last chain applies reduction functions alternating h. creates new way producing false alarm guess position hash value wrong may needlessly evaluate chain although rainbow tables follow chains make fewer tables simple hash chain tables grow beyond certain size without rapidly becoming inefficient due merging chains deal maintain multiple tables lookup must search table rainbow tables achieve similar performance tables k times larger allowing perform factor k fewer lookups rainbow tables use refined algorithm different reduction function link chain hash collision two chains chains merge long collision n't occur position chain increases probability correct crack given table size cost squaring number steps required per lookup lookup routine also needs iterate index first reduction function used chain rainbow tables specific hash function created e.g. md5 tables crack md5 hashes theory technique invented philippe oechslin fast form time/memory tradeoff implemented windows password cracker ophcrack powerful rainbowcrack program later developed generate use rainbow tables variety character sets hashing algorithms including lm hash md5 sha-1 simple case reduction function hash function collision given complete rainbow table one makes sure find corresponding password given hash size password set p time needed compute table length table l average time needed find password matching given hash directly related thus 8-character lowercase alphanumeric passwords case p ≃ 3×10 would easily tractable personal computer 16-character lowercase alphanumeric passwords case p ≃ 10 would completely intractable rainbow table ineffective one-way hashes include large salts example consider password hash generated using following function || concatenation operator codice_1 codice_2 salt value secret may generated random stored password hash large salt value prevents precomputation attacks including rainbow tables ensuring user password hashed uniquely means two users password different password hashes assuming different salts used order succeed attacker needs precompute tables possible salt value salt must large enough otherwise attacker make table salt value older unix passwords used 12-bit salt would require 4096 tables significant increase cost attacker impractical terabyte hard drives sha2-crypt bcrypt methods—used linux bsd unixes solaris—have salts 128 bits larger salt values make precomputation attacks systems infeasible almost length password even attacker could generate million tables per second would still need billions years generate tables possible salts another technique helps prevent precomputation attacks key stretching stretching used salt password intermediate hash values run underlying hash function multiple times increase computation time required hash password instance md5-crypt uses 1000 iteration loop repeatedly feeds salt password current intermediate hash value back underlying md5 hash function user password hash concatenation salt value secret final hash extra time noticeable users wait fraction second time log hand stretching reduces effectiveness brute-force attacks proportion number iterations reduces number attempts attacker perform given time frame principle applied md5-crypt bcrypt also greatly increases time needed build precomputed table absence salt needs done alternative approach called key strengthening extends key random salt unlike key stretching securely deletes salt forces attacker legitimate users perform brute-force search salt value although paper introduced key stretching referred earlier technique intentionally chose different name term key strengthening often arguably incorrectly used refer key stretching rainbow tables precomputation attacks work passwords contain symbols outside range presupposed longer precomputed attacker however tables generated take account common ways users attempt choose secure passwords adding number special character sizable investment computing processing rainbow tables beyond fourteen places length yet common choosing password longer fourteen characters may force attacker resort brute-force methods specific intensive efforts focused lm hash older hash algorithm used microsoft publicly available lm hash particularly vulnerable passwords longer 7 characters broken two sections hashed separately choosing password fifteen characters longer guarantees lm hash generated nearly distributions variations unix linux bsd use hashes salts though many applications use hash typically md5 salt microsoft windows nt/2000 family uses lan manager nt lan manager hashing method based md4 also unsalted makes one popularly generated tables
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Computer security
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islamic world science citation database islamic world science citation database isc citation index established iranian ministry science research technology approved organisation islamic conference indexes journals islamic world announced baku azerbaijan fourth islamic conference ministers higher education scientific research held october 2008 managed islamic world science citation center located shiraz 2009 isc partnered scopus allows isc publications indexed scopus
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Databases
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zend technologies zend technologies ltd. world wide web infrastructure software company headquarters cupertino california u.s. technology center ramat gan tel aviv israel offices france italy germany company operations currently centered development products relating development deployment management php-based web applications including zend studio zend technologies founded andi gutmans zeev suraski along israeli graduates technion developed php initial creation rasmus lerdorf name zend combination suraski gutmans forenames zeev andi 1997 gutmans suraski rewrote parser php-fi originally written lerdorf resulting php 3 1998 redesigned parser completely named zend engine php 4 based first version zend engine 1999 company zend technologies formally established received initial funding israeli venture capital funds platinum neurone ventures walden israel doron gerstel experienced business executive recruited head company ceo 2000 jim jagielski hired cto us operations july 2004 zend technologies raised 8m series c funding established headquarters usa january 2005 intel capital sapphire ventures formerly sap ventures joined existing investors zend technologies june 2006 zend technologies received best startup software company award israeli venture association annual hi tech conference tel aviv award presented israeli prime minister ehud olmert august 2006 zend raised 20 million series funding february 2009 zend co-founder andi gutmans appointed chief executive officer previously serving company vp research development zend also recruited mark burton previously served evp worldwide sales mysql executive chairman october 2015 rogue wave software acquired zend shortly acquired co-founder andi gutmans left company february 2016 zend server web application server running managing php applications zend server comes built-in application monitoring application problem diagnostics caching optimization capabilities web-based administrator console zend server ’ installers native os rpm/deb/msi include tested php distribution zend framework out-of-the-box connectivity common databases java connectivity scalable php-integrated download server linux community edition zend server free complete php stack advertised company suited developing php applications running non-critical applications production zend server community edition supported linux windows iseries i5/os mac os x periodically updated zend starting zend server 7.0 free edition discontinued available paid upgrade zend platform product runs web server monitoring php applications reporting performance possible problems also offers php accelerator often confused free zend optimizer content caching solution including api partial page caching session clustering numerous management tools zend platform used conjunction zend studio remote debugging profiling php applications native server environment zend studio commercial proprietary integrated development environment ide php 2013 along zend server deployed 40,000 companies zend guard product prevent peeping php scripts zend also provides php certification test certifies people succeeding exam zend certified php engineers zce confused zend framework certification intended prove person fully qualified develop php web applications 10,000 zend certified engineers world either php 4 php 5 php 5.3 certifications help zend certified engineers gain employment zend lists persons passed zend php certification exam directory yellow pages php professionals also allow zces place zce logo personal web site/resume php mainly used web development language zce tests candidate variety skills necessary developing web applications php 5 certification exam covers although study guide contents topics consider order prepared exam use new extension php data object pdo layer access databases standard php library spl new set classes specially created manipulate objects sets arrays files zend considers required score pass test confidential well questions inform failing candidates topics made fail known candidates must pass every topic pass test whole believed required score per topic might 75–85 passing zend certification test every candidate gets listing zend certified directory lifetime free enables recruiters hire qualified certified php engineers zend engine heart php originally written andi gutmans zeev suraski first version zend engine shipped php4 zend sponsors developers actively contribute engine main development zend engine today comes contributors php project zend framework open-source object-oriented web application framework written php5 licensed new bsd license simple cloud api open-source php api accessing services multiple cloud vendors configuration changes alone project first project zend launched facilitate php development cloud apigility api builder designed simplify creation maintenance apis zend technologies visits events worldwide spread oss message 2005 zeev suraski delivered speech oss technical seminar organized open standard support organization sunwah pearl linux hong kong trade development council
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Programming language topics
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russell gray russell david gray evolutionary biologist psychologist working applying quantitative methods study cultural evolution human prehistory worked professor university auckland located new zealand although originally trained biology psychology gray become well known studies evolution austronesian language family using computational phylogenetic methods gray also performs research animal cognition one main research-projects studies tool-use among new caledonian crows summer 2014 max planck society announced max planck institute economics jena germany would receive new different mandate along johannes krause gray appointed director new max planck institute science human history commencing february 1 2014
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Computational linguistics
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template toolkit template toolkit tt template engine used primarily building web sites also suitable creating type digital document pdf latex file template toolkit based mini-language allow direct perl templates default unlike competing products e.g mason forces developers separate business logic perl libraries leaving presentation logic templates written perl popular accessories c. released free software licence perl artistic licence gpl tt used templating system various perl application frameworks including catalyst mvc framework cgi :application maypole framework template toolkit written andy wardley prototype tt text :metatext perl module released 1996 first version tt proper released 1999 version 2.00 released 2001 version 3 development last touched january 2010
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Web technology
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clearslide clearslide saas-based sales engagement platform lets users share content sales materials via email links viewer ’ link ‘ live pitch ’ clearslide designed sales marketing teams accessible primarily via annual subscription model users also sign limited time free trial software full access features regular subscription company ’ headquarters san francisco ’ financial district clearslide found october 2009 funded founders initial subscribers company fundraise year following launch august 2012 clearslide raised 28 million series b round financing announcing fuel rapid growth expansion plans march 5 2013 company bought sliderocket vmware second acquisition announced july 2 2013 clearslide bought crunched rival cloud-based sales engagement platform february 2014 clearslide raised 50 million series c funding partnership social+capital partnership led additional contributions greylock partners bessemer venture partners felicis ventures
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Distributed computing architecture
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thread-local storage thread-local storage tls computer programming method uses static global memory local thread use global variables generally discouraged modern programming legacy operating systems unix designed uniprocessor hardware require additional mechanism retain semantics pre-reentrant apis example situations functions use global variable set error condition example global variable codice_1 used many functions c library codice_1 global variable call system function one thread may overwrite value previously set call system function different thread possibly following code different thread could check error condition solution codice_1 variable looks like global fact exists per thread—i.e. lives thread-local storage second use case would multiple threads accumulating information global variable avoid race condition every access global variable would protected mutex alternatively thread might accumulate thread-local variable definition read written threads implying race conditions threads synchronise final accumulation thread-local variable single truly global variable many systems impose restrictions size thread-local memory block fact often rather tight limits hand system provide least memory address pointer sized variable thread-local allows use arbitrarily sized memory blocks thread-local manner allocating memory block dynamically storing memory address block thread-local variable application programming interface api function codice_4 used obtain unused tls slot index tls slot index considered ‘ used ’ codice_5 codice_6 functions used read write memory address thread-local variable identified tls slot index codice_6 affects variable current thread codice_8 function called release tls slot index win32 thread information block thread one entries block thread-local storage table thread tlsalloc returns index table unique per address space call thread copy thread-local storage table hence thread independently use tlssetvalue index obtain specified value via tlsgetvalue index set look entry thread table apart tlsxxx function family windows executables define section mapped different page thread executing process unlike tlsxxx values pages contain arbitrary valid addresses addresses however different executing thread therefore passed asynchronous functions may execute different thread otherwise passed code assume virtual address unique within whole process tls sections managed using memory paging size quantized page size 4kb x86 machines sections may defined inside main executable program dlls contain sections correctly initialized loading loadlibrary pthreads api memory local thread designated term thread-specific data functions codice_9 codice_10 used respectively create delete key thread-specific data type key explicitly left opaque referred codice_11 key seen threads thread key associated thread-specific data via codice_12 data later retrieved using codice_13 addition codice_9 optionally accept destructor function automatically called thread exit thread-specific data null destructor receives value associated key parameter perform cleanup actions close connections free memory etc. even destructor specified program must still call codice_10 free thread-specific data process level destructor frees data local thread apart relying programmers call appropriate api functions also possible extend programming language support thread local storage tls c11 keyword codice_16 used define thread-local variables header codice_17 supported defines codice_18 synonym keyword example usage c++11 introduces codice_18 keyword used following cases aside various compiler implementations provide specific ways declare thread-local variables windows versions vista server 2008 codice_23 works dlls dlls bound executable work loaded loadlibrary protection fault data corruption may occur common lisp provides feature called dynamically scoped variables dynamic variables binding private invocation function children called function abstraction naturally maps thread-specific storage lisp implementations provide threads common lisp numerous standard dynamic variables threads sensibly added implementation language without variables thread-local semantics dynamic binding instance standard variable codice_24 determines default radix integers printed variable overridden enclosing code print integers alternate radix functions execute concurrently different threads binding properly thread-local otherwise thread fight controls global printing radix version 2 static global variables thread-local default declared syntax similar normal global static variables languages global variables must explicitly requested using shared keyword shared keyword works storage class type qualifier – shared variables subject restrictions statically enforce data integrity declare classic global variable without restrictions unsafe __gshared keyword must used java thread-local variables implemented class object threadlocal holds variable type accessible via get/set methods example threadlocal variable holding integer value looks like least oracle/openjdk use native thread-local storage spite os threads used aspects java threading instead thread object stores non-thread-safe map threadlocal objects values opposed threadlocal map thread objects values incurring performance overhead .net framework languages c static fields marked threadstatic attribute .net 4.0 system.threading.threadlocal class available allocating lazily loading thread-local variables also api available dynamically allocating thread-local variables object pascal delphi free pascal threadvar reserved keyword used instead 'var declare variables using thread-local storage cocoa gnustep openstep nsthread object thread-local dictionary accessed thread threaddictionary method perl threads added late evolution language large body extant code already present comprehensive perl archive network cpan thus threads perl default take local storage variables minimise impact threads extant non-thread-aware code perl thread-shared variable created using attribute python programming language |python version 2.4 later local class threading module used create thread-local storage ruby programming language |ruby create/access thread-local variables using =/ methods category threads computing category variable computer science category software design patterns
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Programming language topics
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scunthorpe problem scunthorpe problem unintentional blocking websites e-mails forum posts search results spam filter search engine text contains string letters appear obscene otherwise unacceptable meaning names abbreviations technical terms often cited affected issue problem arises since computers easily identify strings text within document interpreting words kind requires considerable ability interpret wide range contexts possibly across many cultures extremely difficult task result broad blocking rules may result false positives affecting innocent phrases problem named incident 1996 aol profanity filter prevented residents town scunthorpe north lincolnshire england creating accounts aol town name contains substring cunt years later google opt-in safesearch filters apparently made mistake preventing residents searching local businesses included scunthorpe names mistaken decisions obscenity filters include
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Computer security
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socket 604 socket 604 604-pin microprocessor socket designed interface intel xeon processor rest computer provides electrical interface well physical support socket designed support heatsink socket 604 designed intel zero insertion force socket intended workstations server platforms socket contains 604 pins 603 electrical contacts last dummy pin contact 1.27mm pitch regular pin array mate 604-pin processor package socket 604 processors utilize bus speed either 400 533 667 800 1066 mhz manufactured either 130 90 65 45 nm process socket 604 processors inserted socket 603 designed motherboards due one additional pin present socket 603 processors inserted socket 604 designed motherboards since extra pin slot anything 603 cpu socket 604 processors range 1.60 ghz 3.80 ghz higher clock rates found among older slower netburst-based xeons following intel xeon chipsets used socket 604 late socket 604 revivals
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Computer architecture
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elasticity cloud computing cloud computing elasticity defined degree system able adapt workload changes provisioning de-provisioning resources autonomic manner point time available resources match current demand closely possible elasticity defining characteristic differentiates cloud computing previously proposed computing paradigms grid computing dynamic adaptation capacity e.g. altering use computing resources meet varying workload called elastic computing let us illustrate elasticity simple example service provider wants run website iaas cloud moment formula_1 website unpopular single machine commonly virtual machine sufficient serve web users moment formula_2 website suddenly becomes popular example result flash crowd single machine longer sufficient serve users based number web users simultaneously accessing website resource requirements web server might ten machines needed elastic system immediately detect condition provision nine additional machines cloud serve web users responsively time formula_3 website becomes unpopular ten machines currently allocated website mostly idle single machine would sufficient serve users accessing website elastic system immediately detect condition deprovision nine machines release cloud elasticity aims matching amount resource allocated service amount resource actually requires avoiding over- under-provisioning over-provisioning i.e. allocating resources required avoided service provider often pay resources allocated service example amazon ec2 m4 extra-large instance costs us 0.239/hour service allocated two virtual machines one required service provider wastes 2,095 every year hence service provider expenses higher optimal profit reduced under-provisioning i.e. allocating fewer resources required must avoided otherwise service serve users good service example under-provisioning website may make seem slow unreachable web users eventually give accessing thus service provider loses customers long term provider income decrease also reduces profit one potential problem elasticity takes time cloud virtual machine vm acquired time user however may take several minutes acquired vm ready use vm startup time dependent factors image size vm type data center location number vms etc cloud providers different vm startup performance implies control mechanism designed elastic applications must consider decision process time needed elasticity actions take effect provisioning another vm specific application component elastic applications allocate deallocate resources vms demand specific application components makes cloud resources volatile traditional monitoring tools associate monitoring data particular resource i.e vm ganglia nagios longer suitable monitoring behavior elastic applications example lifetime data storage tier elastic application might add remove data storage vms due cost performance requirements varying number used vms thus additional information needed monitoring elastic applications associating logical application structure underlying virtual infrastructure turn generates problems aggregate data multiple vms towards extracting behavior application component running top vms different metrics might need aggregated differently e.g. cpu usage could averaged network transfer might summed deploying applications cloud infrastructures iaas/paas requirements stakeholder need considered order ensure proper elasticity behavior even though traditionally one would try find optimal trade-off cost quality performance real world cloud users requirements regarding behavior complex target multiple dimensions elasticity e.g. sybl cloud applications varying types complexities multiple levels artifacts deployed layers controlling structures must take consideration variety issues approach sense rsybl multi-level control control systems need consider impact lower level control upon higher level ones vice versa e.g. controlling virtual machines web containers web services time well conflicts may appear various control strategies various levels elastic strategies clouds take advantage control-theoretic methods e.g. predictive control experimented cloud scenarios showing considerable advantages respect reactive methods
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Distributed computing architecture
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center internet security nowiki /nowiki center internet security cis 501 c 3 nonprofit organization formed october 2000 mission identify develop validate promote sustain best practice solutions cyber defense build lead communities enable environment trust cyberspace organization headquartered east greenbush new york members including large corporations government agencies academic institutions cis employs closed crowdsourcing model identify refine effective security measures individuals developing recommendations shared community evaluation consensus decision-making process national international level cis plays important role forming security policies decisions maintaining cis controls cis benchmarks hosting multi-state information sharing analysis center ms-isac cis several program areas including ms-isac cis controls cis benchmarks cis communities cis cybermarket program areas cis works wide range entities including academia government private sector general public increase online security providing products services improve security efficiency effectiveness multi-state information sharing analysis center ms-isac round-the-clock cyber threat monitoring mitigation center state local governments operated cis partnership office cybersecurity communications united states department homeland security dhs ms-isac established late 2002 officially launched january 2003 william f. pelgrin chief security officer state new york beginning small group participating states northeast ms-isac came include 50 u.s. states district columbia well u.s. territorial tribal local governments order facilitate expanding scope late 2010 ms-isac transitioned not-for-profit status auspices center internet security transition facilitated cis established reputation providing cybersecurity resources public private sectors ms-isac helps government agencies combat cyberthreats works closely federal law enforcement designated dhs key cyber security resource nation state local territorial tribal sltt governments ms-isac 24x7 cyber security operations center performs network monitoring issues early cyber threat warnings advisories performs vulnerability identification mitigation well incident response main objectives ms-isac described follows elections infrastructure information sharing analysis center ei-isac established election infrastructure subsector government coordinating council gcc critical resource cyber threat prevention protection response recovery nation ’ state local territorial tribal sltt election offices ei-isac operated center internet security inc mission ei-isac improve overall cybersecurity posture sltt election offices collaboration information sharing among members u.s. department homeland security dhs federal partners private sector partners keys success ei-isac provides central resource gathering information cyber threats election infrastructure two-way sharing information among public private sectors order identify protect detect respond recover attacks public private election infrastructure ei-isac comprises representatives sltt election offices contractors supporting sltt election infrastructure cis controls cis benchmarks provide global standards internet security recognized global standard best practices securing systems data attacks cis maintains cis controls popular set 20 security controls map many compliance standards applicable internet things independent consensus process cis benchmarks provide frameworks help organizations bolster security cis offers variety free resources include secure configuration benchmarks automated configuration assessment tools content security metrics security software product certifications cis controls advocate defense-in-depth model help prevent detect malware may 2017 study showed average organizations fail 55 compliance checks established center internet security half violations high severity issues march 2015 cis launched cis hardened images amazon web services response growing concern surrounding data safety information housed virtual servers cloud resources made available amazon machine images six cis benchmarks-hardened systems including microsoft windows linux ubuntu additional images cloud providers added later cis released companion guides cis controls recommendations actions counter cybersecurity attacks new guides released october december 2015 april 2018 cis launched information security risk assessment method implement cis controls called cis ram based upon risk assessment standard docra council cis benchmarks collaboration consensus community cis securesuite members class cis members access additional sets tools resources consensus community made experts field security use knowledge experience help global internet community cis securesuite members made several different types companies ranging size including government agencies colleges universities nonprofits auditors consultants security software vendors organizations cis benchmarks tools cis provides cost allow workers create reports compares system security universal consensus standard fosters new structure internet security everyone accountable shared top executives technology professionals internet users throughout globe cis provides internet security tools scoring feature rates configuration security system hand example cis provides securesuite members access cis-cat pro cross-platform java app scans target systems produces report comparing settings published benchmarks intended encourage motivate users improve scores given software bolsters security internet systems universal consensus standard cis employs draws upon uses accumulated knowledge skillful technology professionals since internet security professionals volunteer contributing consensus reduces costs cis makes cost effective cis cybermarket collaborative purchasing program serves u.s. state local tribal territorial sltt government organizations nonprofit entities public health education institutions improve cybersecurity cost-effective group procurement intent cis cybermarket combine purchasing power governmental nonprofit sectors help participants improve cybersecurity condition lower cost would able attain program assists time intensive costly complex daunting task maintaining cybersecurity working public private sectors bring partners cost-effective tools services combined purchasing opportunities reviewed domain experts three main objectives cis cybermarket cis cybermarket like ms-isac serves government entities non-profits achieving greater cyber security resources page multiple newsletters documents available free charge including cybersecurity handbook cities counties cis communities volunteer global community professionals continuously refine verify cis best practices cybersecurity tools develop structure benchmarks cis uses strategy members organization first form teams teams collect suggestions advice official work recommendations participating organizations teams analyze data information determine vital configuration settings would improve internet system security many work settings possible member team constantly works teammates critically analyzes critiques rough draft consensus forms among team benchmark released general public available download testing among community reviewing feedback testing making necessary adjustments changes final benchmark relevant security tools made available public download cis website process extensive carefully executed thousands security professionals across globe participate according isaca development cis benchmark sun microsystems solaris 2,500 users downloaded benchmark monitoring tools organizations participated founding cis october 2000 include isaca american institute certified public accountants aicpa institute internal auditors iia international information systems security certification consortium isc2 sans institute system administration networking security cis since grown hundreds members varying degrees membership cooperates works variety organizations members national international levels organizations include public private sectors government isacs law enforcement
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Computer security
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socket 603 socket 603 motherboard socket intel xeon processor socket 603 designed intel zero insertion force socket intended workstations server platforms contains 603 contacts arrayed grid center socket contact 1.27mm pitch regular pin array mate 603-pin processor package intel design notes distinguish socket 603 socket 604 low cost low risk robust high volume manufacturable multi-sourceable socket 603 processors bus speed 400 mhz manufactured either 180 nm process 130 nm process socket 603 processors inserted socket 604 designed motherboards socket 604 processors inserted socket 603 designed motherboards due one additional pin present socket 603 processors range 1.4 ghz 3.2 ghz old link http //www.intel.com/assets/pdf/designguide/249672.pdf 11/19/2016 http //www.intel.com/content/dam/www/public/us/en/documents/design-guides/603-pin-socket-guidelines.pdf
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Computer architecture
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blackshades blackshades name malicious trojan horse used hackers control infected computers remotely malware targets computers using microsoft windows -based operating systems according us officials 500,000 computer systems infected worldwide software 2014 united states federal bureau investigation fbi arrested hundreds people blackshade computer fbi crackdown blackshades sold us 40 hack forums reportedly generated us 350,000.00 sales blackshades infects computer systems downloading onto victim computer victim accesses malicious webpage sometimes downloading onto victim computer without victim knowledge known drive-by download external storage devices usb flash drives blackshades also included tools assisted hackers maximizing amount computer systems infected tool sends infected links masquerade innocuous site potential victims via victim social networking service blackshades reportedly used remotely access infected computer without authorization blackshades allows hackers perform many actions infected computer remotely without authorization including ability blackshades reportedly used computer hackers little experience script kiddies hackers use programs developed others attack computer systems blackshades also act ransomware hackers using blackshades restrict access victim computer demand ransom paid hacker order restriction lifted many antivirus programs successfully detect remove blackshades however hackers using blackshades software usually avoid detection blackshades infections using software obfuscates blackshades binary avoid detection antivirus programs blackshades organization also sold along blackshades software 2012 citizen lab eff reported use blackshades target opposition forces syria 2015 stefan rigo leeds given 40-week suspended sentence using blackshades 14 people 7 knew personally reported paid software using ex-girlfriend payment card 2012 fbi ran sting operation called operation card shop led 24 arrests hackers eight countries one arrested michael hogue also known xvisceral online hacking communities hogue co-creator blackshades arrested indicted charges commonly known computer fraud abuse act sentenced five years probation 20 years suspended prison sentence 2014 fbi coordinated worldwide operation combat use malware leading arrest almost one hundred people nineteen countries may 19 charges laid united states five individuals two men identified developers blackshades three men sold software used infiltrate people computers exactly 359 searches conducted 1,100 electronic devices seized part operation according fbi 500,000 computers 100 countries infected malware blackshades sold typically us 40 reportedly generated us 350,000 sales
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Computer security
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wcf data services wcf data services formerly ado.net data services codename astoria platform microsoft calls data services actually combination runtime web service services exposed also includes data services toolkit lets astoria data services created within asp.net astoria project announced mix 2007 first developer preview made available april 30 2007 first ctp made available part asp.net 3.5 extensions preview final version released part service pack 1 .net framework 3.5 august 11 2008 name change ado.net data services wcf data services announced 2009 pdc wcf data services exposes data represented entity data model edm objects via web services accessed http data addressed using rest-like uri data service accessed via http get method uri return data web service configured return data either plain xml json rdf+xml initial release formats like rss atom supported though may future addition using http methods like put post delete data updated well post used create new entities put updating entity delete deleting entity windows communication foundation wcf comes rescue find able achieve want achieve using web services i.e. protocols support even duplex communication wcf define service configure way used via http tcp ipc even message queues consume web services using server side scripts asp.net javascript object notations json even rest representational state transfer understanding basics say wcf service used communicate using different protocols different kinds applications need understand achieve want use wcf service application three major questions 1.where wcf service located client perspective 2.how client access service i.e. protocols message formats 3.what functionality service providing clients answer three questions creating consuming wcf service lot easier us wcf service concept endpoints wcf service provides endpoints client applications use communicate wcf service answer questions known abc wcf services fact main components wcf service let tackle question one one address like webservice wcf service also provides uri used clients get wcf service uri called address wcf service solve first problem locate wcf service us binding able locate wcf service one think communicate service protocol wise binding defines wcf service handles communication could also define communication parameters like message encoding etc solve second problem communicate wcf service us contract question one left functionalities wcf service provides contract defines public data interfaces wcf service provides clients uris representing data contain physical location service well service name also need specify edm entity-set specific entity instance respectively former list entities collection set whereas latter list entity indexed someartist uris also specify traversal relationship entity data model example traverses relationship genre sql parlance joins genre table retrieves instances genre associated entity somesong simple predicates also specified uri like fetch items indexed someartist release 2006 filtering partition information also encoded url although presence skip top keywords indicates paging support data services version 1 method determining number records available thus impossible determine many pages may odata 2.0 spec adds support count path segment return count entities inlinecount retrieve page worth entities total count without separate round-trip ...
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Web technology
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language model statistical language model probability distribution sequences words given sequence say length assigns probability formula_1 whole sequence language model provides context distinguish words phrases sound similar example american english phrases recognize speech wreck nice beach sound similar mean different things data sparsity major problem building language models possible word sequences observed training one solution make assumption probability word depends previous n words known n -gram model unigram model n 1 unigram model also known bag words model estimating relative likelihood different phrases useful many natural language processing applications especially generate text output language modeling used speech recognition machine translation part-of-speech tagging parsing optical character recognition handwriting recognition information retrieval applications speech recognition sounds matched word sequences ambiguities easier resolve evidence language model integrated pronunciation model acoustic model language models used information retrieval query likelihood model separate language model associated document collection documents ranked based probability query q document language model formula_2 commonly unigram language model used purpose unigram model treated combination several one-state finite automata splits probabilities different terms context e.g formula_3 formula_4 model probability word depends word probability document one-state finite automata units automaton probability distribution entire vocabulary model summing 1 following illustration unigram model document probability generated specific query calculated different documents unigram models different hit probabilities words probability distributions different documents used generate hit probabilities query documents ranked query according probabilities example unigram models two documents information retrieval contexts unigram language models often smoothed avoid instances p term 0 common approach generate maximum-likelihood model entire collection linearly interpolate collection model maximum-likelihood model document smooth model n -gram model probability formula_1 observing sentence formula_8 approximated assumed probability observing word w context history preceding − 1 words approximated probability observing shortened context history preceding n − 1 words n order markov property conditional probability calculated n -gram model frequency counts terms bigram trigram language models denote n -gram models n 2 n 3 respectively typically n -gram model probabilities derived directly frequency counts models derived way severe problems confronted n -grams explicitly seen instead form smoothing necessary assigning total probability mass unseen words n -grams various methods used simple add-one smoothing assign count 1 unseen n -grams uninformative prior sophisticated models good-turing discounting back-off models bidirectional representations condition pre- post- context e.g. words layers bigram n 2 language model probability sentence saw red house approximated whereas trigram n 3 language model approximation note context first n – 1 n -grams filled start-of-sentence markers typically denoted nowiki /nowiki additionally without end-of-sentence marker probability ungrammatical sequence *i saw would always higher longer sentence saw red house maximum entropy language models encode relationship word n-gram history using feature functions equation formula_13 formula_14 partition function formula_15 parameter vector formula_16 feature function simplest case feature function indicator presence certain n-gram helpful use prior formula_15 form regularization log-bilinear model another example exponential language model neural language models continuous space language models use continuous representations embeddings words make predictions models make use neural networks continuous space embeddings help alleviate curse dimensionality language modeling language models trained larger larger texts number unique words vocabulary increases number possible sequences words increases exponentially size vocabulary causing data sparsity problem exponentially many sequences thus statistics needed properly estimate probabilities neural networks avoid problem representing words distributed way non-linear combinations weights neural net alternate description neural net approximates language function neural net architecture might feed-forward recurrent former simpler latter common typically neural net language models constructed trained probabilistic classifiers learn predict probability distribution i.e. network trained predict probability distribution vocabulary given linguistic context done using standard neural net training algorithms stochastic gradient descent backpropagation context might fixed-size window previous words network predicts feature vector representing previous words another option use future words well past words features estimated probability third option allows faster training invert previous problem make neural network learn context given word one maximizes log-probability called skip-gram language model basis word2vec program instead using neural net language models produce actual probabilities common instead use distributed representation encoded networks hidden layers representations words word mapped onto -dimensional real vector called word embedding size layer output layer representations skip-gram models distinct characteristic model semantic relations words linear combinations capturing form compositionality example models function maps word -d vector representation ≈ made precise stipulating right-hand side must nearest neighbor value left-hand side positional language model assesses probability given words occurring close one another text necessarily immediately adjacent similarly bag-of-concepts models leverage semantics associated multi-word expressions buy_christmas_present even used information-rich sentences like today bought lot nice christmas presents various data sets developed use evaluate language processing systems include
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Computational linguistics
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joule programming language joule concurrent dataflow programming language designed building distributed applications concurrent order statements within block irrelevant operation block statements executed whenever possible based inputs everything joule happens sending messages control flow instead programmer describes flow data making dataflow programming language considered precursor e programming language numerals consist ascii digits 0-9 identifiers unicode sequences digits letters operator characters begin letter also possible form identifiers using unicode sequences including whitespace enclosed either straight standard ‘ ’ single quotes backslash escape character keywords start letter except • keyword send information operators consist unicode sequences digits letters operator characters beginning operator character labels identifiers followed colon root joule imperative language statement-based language rich expression syntax transforms easily relational syntax underneath complex expressions become separate statements site original expression replaced reference acceptor results channel therefore nested expressions still compute completely concurrently embedding statement identifiers may name channel communicate server case said bound channel
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Computer architecture
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jello framework jello end-to-end java application framework optimized google app engine including comprehensive data authorization model powerful restful engine out-of-the-box ui views jello rest offers clean simple follow json format protocol schema follows odata specification following components part jello framework
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Web technology
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ssh-keygen ssh-keygen standard component secure shell ssh protocol suite found unix unix-like microsoft windows computer systems used establish secure shell sessions remote computers insecure networks use various cryptographic techniques ssh-keygen utility used generate manage convert authentication keys ssh-keygen able generate key using one three different digital signature algorithms help ssh-keygen tool user create passphrase keys key types provide unattended operation passphrase left empty increased risk keys differ keys used related tool gnu privacy guard openssh-based client server programs included windows 10 since version 1803 ssh client key agent enabled available default ssh server optional feature-on-demand originally ssh protocol version 1 deprecated rsa algorithm supported 2016 rsa still considered strong recommended key length increased time ssh protocol version 2 additionally introduced support dsa algorithm dsa algorithm ties american national security agency nsa aspects security called question edward snowden global surveillance disclosures particularly light bullrun decryption program subsequently openssh added support third digital signature algorithm ecdsa key format longer uses previous pem file format private keys depend upon openssl library provide cryptographic implementation fourth format supported using ed25519 originally developed independent cryptography researcher daniel j. bernstein syntax ssh-keygen command follows important options ssh-keygen command follows ssh-keygen utility uses various files storing public private keys files used ssh-keygen utility follows
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Operating systems
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berkeley printing system berkeley printing system one several standard architectures printing unix platform originated 2.10bsd used bsd derivatives freebsd netbsd openbsd dragonfly bsd system running print architecture could traditionally identified use user command lpr primary interface print system opposed system v printing system lp command typical user commands available berkeley print system lpd program daemon programs communicate programs support line printer daemon protocol machines network submit jobs print queue machine running berkeley printing system berkeley printing system user commands submit jobs machines support protocol
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Operating systems
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nokia e65 nokia e65 smartphone eseries range s60 platform third edition device slide action shared many features n95 quad band gsm 3g wifi bluetooth released around time thinner lighter without gps followed fairly quickly e66 similar gained fm radio newer release s60 a2dp bluetooth gps 3.2 mpixel camera operation times vary depending network usage many users experienced problems sim connecting network using phone time bring phone nokia center get phone repaired replaced cause seems design problem sim container chassis phone sim container mainly built thin metal foil time tends bend thus disconnecting sim mobile phone sim contacts problem apparently solved putting bit paper metal foil sim enabling make contact also difficulties making connection wlan networks use eap-peap mschapv2 protocols update phone firmware true firmware version 3.0633.69 users experience problems phone connecting third party gps devices bluetooth seems compatibility flaw nokia bluetooth stack nokia maps devices connect well used google maps e65
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Operating systems
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marionnet marionnet virtual network laboratory allows users define configure run complex computer networks without need physical setup single possibly even non-networked gnu/linux host machine required simulate whole ethernet network complete computers routers hubs switches cables support also provided integrating virtual network physical host network marionnet born april 2005 simple textual interface netkit written ocaml jean-vincent loddo paris 13 university networking course code since completely rewritten redesigned september 2005 order remove dependency netkit ease construction graphical interface partly built dot architecture extended system made general luca saiu joined project 2007 contributing particular dynamic reconfiguration aspects system active use several universities metropolitan france countries marionnet reached fairly stable state successfully used teaching networks several universities around world current development centered around making system easier use average end user particular emphasis documentation internationalization way mostly marionnet_i18n branch gnu gettext far marionnet presented two international computer science conferences many french events fosdem top gnu/linux host emulation guest machines achieved user mode linux technology allows run many linux kernels user space regular processes vde virtual distributed ethernet project responsible linking together uml machines virtual network purpose emulate cable hub switch devices allowing also introduce perturbations communication top raw emulated network marionnet acts coherent manager gui marionnet example complex concurrent application written functional language using relatively advanced programming techniques marionnet showed good performance complex networks ~15 machines even relatively old machines remaining responsive main concern disk usage largely depends distribution choice pinocchio custom distro developed meet average needs main goal marionnet teaching computers networks university laboratories although could valuable tool also high schools despite teaching-oriented marionnet may used emulate networks test development purposes quite easy set fast even complicated configurations possibility reverting filesystem changes virtual machines makes quite flexible
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Operating systems
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network mapping network mapping study physical connectivity networks e.g internet network mapping discovers devices network connectivity confused network discovery network enumerating discovers devices network characteristics operating system open ports listening network services etc. field automated network mapping taken greater importance networks become dynamic complex nature images first attempts large scale map internet produced internet mapping project appeared wired magazine maps produced project based layer 3 ip level connectivity internet see osi model different aspects internet structure also mapped recent efforts map internet improved sophisticated methods allowing make faster sensible maps example effort opte project attempting develop system capable mapping internet single day map internet project maps 4 billion internet locations cubes 3d cyberspace users add urls cubes re-arrange objects map early 2011 canadian based isp peer 1 hosting created map internet depicts graph 19,869 autonomous system nodes connected 44,344 connections sizing layout autonomous systems calculated based eigenvector centrality measure central network autonomous system graph theory used better understand maps internet help choose many ways visualize internet maps projects attempted incorporate geographical data internet maps example draw locations routers nodes map world others concerned representing abstract structures internet allocation structure purpose ip space many organizations create network maps network system maps made manually using simple tools microsoft visio mapping process simplified using tools integrate auto network discovery network mapping one example ip fabric platform many vendors notable network mappers list enable customize maps include labels add un-discoverable items background images sophisticated mapping used help visualize network understand relationships end devices transport layers provide service items bottlenecks root cause analysis easier spot using tools three main techniques used network mapping snmp based approaches active probing route analytics snmp based approach retrieves data router switch mibs order build network map active probing approach relies series traceroute-like probe packets order build network map route analytics approach relies information routing protocols build network map three approaches advantages disadvantages methods use two prominent techniques used today create internet maps first works data plane internet called active probing used infer internet topology based router adjacencies second works control plane infers autonomous system connectivity based bgp data bgp speaker sends 19-byte keep-alive messages every 60 seconds maintain connection technique relies traceroute-like probing ip address space probes report back ip forwarding paths destination address combining paths one infer router level topology given pop active probing advantageous paths returned probes constitute actual forwarding path data takes networks also likely find peering links isp however active probing requires massive amounts probes map entire internet likely infer false topologies due load balancing routers routers multiple ip address aliases decreased global support enhanced probing mechanisms source-route probing icmp echo broadcasting ip address resolution techniques leaves type probing realm network diagnosis technique relies various bgp collectors collect routing updates tables provide information publicly bgp entry contains path vector attribute called path path represents autonomous system forwarding path given origin given set prefixes paths used infer as-level connectivity turn used build topology graphs however paths necessarily reflect data actually forwarded adjacencies nodes represent policy relationship single link reality several router links also much harder infer peerings two nodes peering relationships propagated isp customer networks nevertheless support type mapping increasing isp offer peer public route collectors route-views ripe new toolsets emerging cyclops netviews take advantage new experimental bgp collector bgpmon netviews build topology maps seconds visualize topology changes moments occurring actual router hence routing dynamics visualized real time comparison tools using bgpmon another tool nettransformer able discover generate bgp peering maps either snmp polling converting mrt dumps graphml file format nettransformer allows us also perform network diffs two dumps thus reason bgp peering evolved years whatsup gold monitoring tool tracks networks servers applications storage devices virtual devices incorporates infrastructure management application performance management
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Computer security
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key key tool used formal verification java programs accepts specifications written java modeling language java source files transformed theorems dynamic logic compared program semantics likewise defined terms dynamic logic key significantly powerful supports interactive i.e hand fully automated correctness proofs failed proof attempts used efficient debugging verification-based testing several extensions key order apply verification c programs hybrid systems key jointly developed karlsruhe institute technology germany technische universität darmstadt germany chalmers university technology gothenburg sweden licensed gpl usual user input key consists java source file annotations jml translated key internal representation dynamic logic given specifications several proof obligations arise discharged i.e proof found ends program symbolically executed resulting changes program variables stored so-called updates program processed completely remains first-order logic proof obligation heart key system lies first-order theorem prover based sequent calculus used close proof interference rules captured called taclets consist simple language describe changes sequent theoretical foundation key formal logic called java card dl dl stands dynamic logic version first-order dynamic logic tailored java card programs example allows statements formulas like formula_1 intuitively says post-condition formula_2 must hold program states reachable executing java card program formula_3 state satisfies pre-condition formula_4 equivalent formula_5 hoare calculus formula_4 formula_2 purely first order dynamic logic however extends hoare logic formulas may contain nested program modalities formula_8 quantification formulas contain modalities possible also dual modality formula_9 includes termination dynamic logic seen special multi-modal logic infinite number modalities java block formula_3 modalities formula_8 formula_9 heart key system lies first-order theorem prover based sequent calculus sequent form formula_13 formula_14 assumptions formula_15 propositions sets formulas intuitive meaning formula_16 holds true means deduction initial sequent representing proof obligation shown constructible fundamental first-order axioms equality formula_17 program modalities eliminated symbolic execution instance formula formula_18 logically equivalent formula_19 example shows symbolic execution dynamic logic similar calculating weakest preconditions formula_20 formula_21 essentially denote thing – two exceptions firstly formula_22 function meta-calculus formula_20 really formula given calculus secondly symbolic execution runs program forward actual execution would save intermediate results assignments key introduces concept called updates similar substitutions applied program modality fully eliminated syntactically updates consist parallel side-effect free assignments written curly braces front modality example symbolic execution updates formula_24 transformed formula_25 first step formula_26 second step modality empty backwards application update postcondition yields precondition formula_27 could take value suppose one wants prove following method calculates product non-negative integers formula_27 formula_29 one thus starts proof premise formula_30 to-be-shown conclusion formula_31 note tableaux sequent calculi usually written upside-down i.e. starting sequent appears bottom deduction steps go upwards proof seen figure right symbolic execution debugger visualizes control flow program symbolic execution tree contains feasible execution paths program certain point provided plugin eclipse development platform key usable model-based testing tool generate unit tests java programs model test data test case derived consists formal specification provided jml symbolic execution tree implementation test computed key system key free software written java licensed gpl downloaded project website source currently pre-compiled binaries available another possibility key executed directly via java web start without need compilation installation key-hoare built top key features hoare calculus state updates state updates means describing state transitions kripke structure calculus seen subset one used main branch key due simplicity hoare calculus implementation essentially meant exemplify formal methods undergraduate classes keymaera previously called hykey deductive verification tool hybrid systems based calculus differential dynamic logic dl extends key tool computer algebra systems like mathematica corresponding algorithms proof strategies used practical verification hybrid systems keymaera developed university oldenburg carnegie mellon university name tool chosen homophone chimera hybrid animal ancient greek mythology keymaerax developed carnegie mellon university successor keymaera completely rewritten key c adaption key system misra c subset c programming language variant longer supported also adaptation use key symbolic execution abstract state machines developed eth zürich variant longer supported information found weblink
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Programming language topics
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william f. friedman william frederick friedman september 24 1891 – november 12 1969 us army cryptographer ran research division army signal intelligence service sis 1930s parts follow-on services 1950s 1940 subordinates led frank rowlett broke japan purple cipher thus disclosing japanese diplomatic secrets america entrance world war ii friedman born wolf friedman chişinău bessarabia son frederick friedman jew bucharest worked translator linguist russian postal service daughter well-to-do wine merchant friedman family fled russia 1892 escape virulent anti-semitism ending pittsburgh pennsylvania three years later first name changed william child friedman introduced cryptography short story gold-bug edgar allan poe studied michigan agricultural college known today michigan state university east lansing received scholarship work genetics cornell university meanwhile george fabyan ran private research laboratory study personally interesting project decided set genetics project referred friedman friedman joined fabyan riverbank laboratories outside chicago september 1915 head department genetics one projects ran studied effects moonlight crop growth experimented planting wheat various phases moon another fabyan pet projects research secret messages sir francis bacon allegedly hidden various texts reigns elizabeth james research carried elizabeth wells gallup believed discovered many messages works william shakespeare convinced bacon written many shakespeare works friedman become something expert photographer working projects asked travel england several occasions help gallup photograph historical manuscripts research became fascinated work courted elizebeth smith gallup assistant accomplished cryptographer married soon became director riverbank department codes ciphers well department genetics time friedman wrote series 23 papers cryptography collectively known riverbank publications including first description index coincidence important mathematical tool cryptanalysis entry united states world war fabyan offered services department codes ciphers government federal department existed kind work although army navy embryonic departments various times soon riverbank became unofficial cryptographic center us government period friedmans broke code used german-funded indian radicals us planned ship arms india gain independence britain analyzing format messages riverbank realized code based dictionary sort cryptographic technique common time friedmans soon managed decrypt messages long case come trial book come light german-english dictionary published 1880 united states government decided set cryptological service sent army officers riverbank train friedman support program friedman wrote series technical monographs completing seven early 1918 enlisted army went france serve personal cryptographer general john j. pershing returned us 1920 published eighth monograph index coincidence applications cryptography considered important publication modern cryptography time texts army cryptographic training well thought remained classified several decades 1921 became chief cryptanalyst war department later led signals intelligence service sis —a position kept quarter century 1929 american black chamber new york city disbanded files entrusted sis cryptographic intelligence services reorganized suit new position war department friedman coined several terms including cryptanalysis wrote many monographs cryptography one written mostly spare time first draft elements cryptanalysis later expanded four volumes became u.s. army cryptographic main textbook reference realizing mathematical language skills essential sis work friedman managed get authority hire three men mathematical training language knowledge solomon kullback frank rowlett abraham sinkov went distinguished service decades addition also finally able hire man fluent japanese john hurt period elizebeth friedman continued work cryptology became famous number trials involving rum-runners coast guard fbi prohibition 1920s several new cipher machines developed generally based using typewriter mechanics basic electrical circuitry early example hebern rotor machine designed us 1915 edward hebern system offered security simplicity use hebern heavily promoted investors friedman realized new rotor machines would important devoted time analyzing hebern design period years developed principles analysis discovered several problems common rotor-machine designs examples dangerous features allowed cracking generated code included rotors step one position keypress putting fastest rotor one turns every keypress either end rotor series case collecting enough ciphertext applying standard statistical method known kappa test showed could albeit great difficulty crack cipher generated machine friedman used understanding rotor machines develop several immune attacks best lot sigaba—which destined become us highest-security cipher machine world war ii—was co-invented frank rowlett least one patent related finally granted friedman died 1939 japanese introduced new cipher machine sensitive diplomatic traffic replacing earlier system sis referred red new cipher sis called purple different much difficult navy cryptological unit op-20-g sis thought might related earlier japanese cipher machines agreed sis would handle attack system several months trying discover underlying patterns purple ciphertexts sis team led friedman rowlett extraordinary achievement figured purple unlike german enigma hebern design use rotors stepper switches like automated telephone exchanges leo rosen sis built machine — later discovered using identical model switch japanese designer chosen thus end 1940 sis constructed exact analog purple machine without ever seen one duplicate machines understanding purple sis could decrypt increasing amounts japanese traffic one intercept message japanese embassy washington d.c. ordering end december 7 1941 negotiations us message gave clear indication impending war delivered us state department hours prior attack pearl harbor controversy whether us foreknowledge pearl harbor attack roiled well 21st century 1941 friedman hospitalized nervous breakdown widely attributed mental strain work purple remained hospital four-man team — abraham sinkov leo rosen sis lt. prescott currier lt. robert weeks u.s. navy op-20-g — visited british establishment government code cypher school bletchley park gave british purple machine exchange details design enigma machine british decrypted enigma cipher however friedman visited bletchley park april 1943 played key role drawing 1943 brusa agreement. ref name=bletchleyparkdiary-2013
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Computer security
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elm information security elm saudi joint stock company owned public investment fund pif investment arm saudi ministry finance elm services provided forms beneficiaries including government corporate sector individuals elm services provided following sectors
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Computer security
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pop smtp pop smtp smtp pop method authentication used mail server software helps allow users option send e-mail location long demonstrably also fetch mail place pop smtp approach superseded smtp authentication due smtp authentication widely used recent years purposes technically users allowed use smtp ip address long previously made successful login pop service mail hosting provider address within predefined timeout period main advantage process generally transparent average user connecting email client almost always make connection fetch new mail sending new mail disadvantages include potentially complex setup mail hosting provider requiring sort communication channel pop service smtp service uncertainty much time users take connect via smtp send mail connecting pop users handled method need resort authorization methods also cases users come externally controlled dynamically assigned addresses smtp server must careful giving much leeway allowing unauthorized connections possibility race conditions leaving open mail relay unintentionally exposed
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Computer security
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web platform installer web platform installer web pi freeware closed-source package management system installs non-commercial development tools dependencies part microsoft web platform including ability install third-party software added version 2.0 released september 24 2009. web pi install 82 titles web pi 2.0 options populated dynamically runtime microsoft servers allowing installation options updated without need download newer versions web pi july 7 2010 microsoft announced web pi 3 includes webmatrix new set integrated tools web development web pi 3 installs additional tools web development including iis developer express sql server compact dotnetnuke web pi features offline mode products downloaded local cache machine internet access available use cached files different machine later however web pi still usable environments internet connectivity local administrator privileges mutually exclusive i.e given process either authenticate transparent proxy high system integrity level
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Operating systems
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linux foundation linux foundation lf non-profit technology consortium founded 2000 merger open source development labs free standards group standardize linux support growth promote commercial adoption also hosts promotes collaborative development open source software projects began 2000 open source development labs osdl became organization today osdl merged free standards group fsg linux foundation sponsors work linux creator linus torvalds lead maintainer greg kroah-hartman supported members cisco fujitsu hitachi huawei ibm intel microsoft nec oracle qualcomm samsung vmware well developers around world recent years linux foundation expanded services events training certification open source projects projects hosted linux foundation include open network automation platform onap hyperledger cloud native computing foundation cloud foundry foundation xen project many others origins linux foundation traced 1993 patrick d'cruze started linux international email list known li 1993 comdex bob young introduced mark bolzern li list shortly thereafter bolzern shared vision asked make members list bolzern funded li activities others eventually joined vision defined among things entity deal traditional public relations behalf linus torvalds file trademark behalf linus among many things described bolzern direction li became collaboration linux related vendors technologists heading single direction served everyone entire linux movement according original vision became clear bolzern could continue ceo workgroup solutions/linuxmall executive director linux international time perceived conflict interest mid 1994 bolzern young recruited jon maddog hall executive director position turn filed corporate paperwork behalf new board directors bolzern also remained board well continued leading trade show marketing efforts late 1999 included many trips press relations user groups bolzern maddog bolzern also organized managed launch linux pavilions major trade shows time uniforum comdex usenix eventually maddog helping establish atlanta linux showcase helped larry augustin li board member silicon valley linux user group create san francisco linux expo especially notable 94–98 timeframe anti-fraud linux trademark filing led li already included li suite projects mid 90s linux mark institute linux base standard certification programs trade show press relationships along actually vendor association page outlining linux international membership latter half 90s list presented alphabetical agreed order merit li linux bolzern maddog continued provide bulk funding 1998 augmented vendor individual membership fees individuals sponsors joined li vision 1999 li already become vendor-neutral 501c6 non-profit industry association linux linus torvalds blessing linus focused development technical excellence linux li primary purpose industry marketing organization also supported linux related certification programs along development essential projects education vision huge large vendors began come party expected sophistication thus help needed even bolzern distracted wife diagnosed cancer maddog becoming weary load everyone support augustin took action suggested another organization formed continue 2000 osdl founded appealing linux international board directors number fundamental projects still part linux foundation today osdl non-profit organization supported global consortium aimed accelerate deployment linux enterprise computing recognized center-of-gravity linux industry 9 jon maddog hall went different direction li.org 2003 linus torvalds creator freely available linux kernel announced would join organization osdl fellow work full-time future versions linux 2007 osdl merged free standards group another organization promoting adoption linux time jim zemlin headed fsg took executive director linux foundation remains today september 11 2011 linux foundation website taken due breach discovered 27 days prior including limited attendant subdomains linux foundation linux.com major parts including openprinting still offline october 20 2011 restoration complete january 4 2012 although one site linux developer network restored march 2014 linux foundation announced would begin building mooc program nonprofit education platform edx aim collaboration serve rapidly growing demand linux expertise vehicle available anyone anywhere world time point first offering basic introduction linux course library since expanded include intro cloud infrastructure technologies intro devops intro openstack november 16 2016 linux foundation announced microsoft traditionally seen competitor joined organization platinum member news widely recognized evidence industry-wide embrace open source software scott guthrie executive vice president microsoft cloud enterprise group explained company excited join linux foundation partner community help developers capitalize shift intelligent cloud mobile experiences linux foundation brought number notable changes open source industry 2017 inaugural open source summit los angeles collection open source guides enterprise created partnership todo group open source managers/executives announced provide transparency new open source projects looking solidify stance strategy staying power event also platform announce foundation chaoss project build platform analyzing open source projects despite rivalry rideshare market uber lyft displayed unity announcing two new projects cloud native computing foundation cncf umbrella open source summit january 23 2018 linux foundation announced six open source networking projects onap opnfv opendaylight fd.io pnda snas would united one umbrella project called lf networking fund lfn arpit joshipura formerly director networking orchestration foundation became executive director lfn heather kirksey formerly director opnfv became linux foundation vp nfv participation lfn voluntary networking projects free decide whether join fund projects continues maintain technical independence linux foundation dedicated building sustainable ecosystems around open source projects accelerate technology development commercial adoption home linux creator linus torvalds lead maintainer greg kroah-hartman provides neutral home linux kernel development protected accelerated years come also fosters innovation hosting collaborative events among linux technical community software developers industry end users solve pressing issues facing linux open source linux foundation supports linux community offering technical information education annual events open source leadership summit linux kernel developers summit open source summit formerly known linuxcon inaugurated september 2009 developer travel fund available introduced october 2017 community data license agreement cdla legal framework sharing data two initial cdla licenses march 3 2009 linux foundation announced would take management linux.com previous owners sourceforge inc site relaunched may 13 2009 shifting away previous incarnation news site become central source linux tutorials information software documentation answers across server desktop/netbook mobile embedded areas also includes directory linux software hardware much like linux linux.com plans rely community create drive content conversation linux foundation training program features instructors content straight leaders linux developer open source communities participants receive linux training vendor-neutral technically advanced created actual leaders linux development community linux foundation linux training courses online in-person events corporate onsite give attendees broad foundational knowledge networking needed thrive careers march 2014 linux foundation edx partnered offer free massive open online class titled introduction linux first series ongoing free offerings organizations whose current catalogue moocs include intro devops intro cloud foundry cloud native software architecture intro apache hadoop intro cloud infrastructure technologies intro openstack december 2015 linux foundation introduced self-paced course designed help prepare administrators openstack foundation certified openstack administrator exam part partnership microsoft announced december 2015 linux azure certification would awarded individuals pass microsoft exam 70-533 implementing microsoft azure infrastructure solutions linux foundation certified system administrator lfcs exam early 2017 annual open source leadership summit announced linux foundation would begin offering inclusive speaker orientation course partnership national center women information technology free course designed give participants practical skills promote inclusivity presentations patent commons consists patented software made available open source community software considered commons patent owner must guarantee developers sued infringement though may restrictions use patented code concept first given substance red hat 2001 published patent promise patent commons project launched november 15 2005 open source development labs osdl core project online patent commons reference library aggregating documenting information patent-related pledges legal solutions directed open-source software community project listed 53 patents linux foundation projects originally collaborative projects independently funded software projects harness power collaborative development fuel innovation across industries ecosystems 500 companies thousands developers around world contribute open source software projects september 2015 total lines source code present linux foundation collaborative projects 115,013,302 estimated total amount effort required retrace steps collaborative development projects 41,192.25 person years words would take 1,356 developers 30 years recreate code bases time total economic value development costs linux foundation collaborative projects estimated 5 billion continued investment open source projects growth number projects hosted number rose 15.6 billion september 2017 projects include alphabetical order alljoyn open source application framework connected devices services formed allseen alliance 2013 project sponsored independent linux foundation project open connectivity foundation ocf automotive grade linux agl collaborative open source project developing linux-based open platform connected car serve de facto standard industry although initially focused in-vehicle infotainment ivi agl roadmap includes instrument cluster heads display telematics autonomous driving goals agl provide june 30 2014 agl announced first release based tizen ivi primarily demo applications agl expanded first reference platform unified code base ucb distribution first ucb release nicknamed agile albacore released january 2016 leverages software components agl tizen genivi alliance ucb 2.0 nicknamed brilliant blowfish made available july 2016 included new features like rear seat display video playback audio routing application framework ucb 3.0 charming chinook released january 2017 agl plans support additional use cases instrument clusters telematics systems cgl workgroup main purpose interface network equipment providers carriers gather requirements produce specifications linux distribution vendors implement also serves use unimplemented requirements foster development projects assist upstream integration requirements cloud foundry open source multi cloud application platform service paas governed cloud foundry foundation 501 c 6 organization january 2015 cloud foundry foundation created independent not-for-profit linux foundation project foundation exists increase awareness adoption cloud foundry grow contributor community create cohesive strategy across member companies foundation serves neutral party holding cloud foundry intellectual property cloud native computing foundation cncf founded 2015 promote containers announced kubernetes 1.0 open source container cluster manager contributed foundation google seed technology founding members included google coreos mesosphere red hat twitter huawei intel cisco ibm docker univa vmware order establish qualified representatives technologies governed cncf program announced inaugural cloudnativeday toronto august 2016 serial entrepreneur dan kohn also helped launch cii project current executive director august 2018 google announced handing operational control project community kubernetes open source framework automating deployment managing applications containerized clustered environment aims provide better ways managing related distributed components across varied infrastructure originally designed google donated linux foundation form cloud native computing foundation kubernetes seed technology large diverse community supporting project made staying power robust older technologies ilk container network interface cni cloud native computing foundation project provides networking linux containers containerd industry-standard core container runtime currently available daemon linux windows manage complete container lifecycle host system 2015 docker donated oci specification linux foundation reference implementation called runc coredns dns server chains plugins cloud native computing foundation member project originally built lyft move architecture away monolith envoy high-performance open source edge service proxy makes network transparent applications lyft contributed envoy cloud native computing foundation september 2017 fluentd open source data collector allowing user unify data collection consumption better use understanding data grpc modern open source high performance rpc framework run environment project formed 2015 google decided open source next version rpc infrastructure stubby project number early large industry adopters square inc. netflix cisco created uber engineering jaeger open source distributed tracing system inspired google dapper paper openzipkin community used tracing microservice-based architectures including distributed context propagation distributed transaction monitoring root cause analysis service dependency analysis performance/latency optimization cloud native computing foundation technical oversight committee voted accept jaeger 12th hosted project september 2017 linkerd cncf member project providing resilient service mesh cloud native applications tool based jvm java virtual machine developers help improve communications among microservices notary open source project allows anyone trust arbitrary collections data opentracing cloud native computing foundation member project offers consistent expressive vendor-neutral apis popular platforms cloud native computing foundation member project prometheus cloud monitoring tool sponsored soundcloud early iterations tool currently used digital ocean ericsson coreos docker red hat google august 2018 tool designated graduated project cloud native computing foundation rkt cloud native computing foundation project pod-native container engine linux composable secure built standards update framework tuf helps developers secure new existing software update systems often found vulnerable many known attacks tuf addresses widespread problem providing comprehensive flexible security framework developers integrate software update system community health analytics open source software chaoss project announced 2017 open source summit north america los angeles overall project aims provide transparency health security metrics open-source projects code aurora forum consortium companies projects serving mobile wireless industry software projects concerns e.g android msm femto linux project llvm msm wlan linux-msm cord central office re-orchestrated datacenter combines sdn nfv cloud commodity infrastructure open building blocks project introduced on.lab june 2015 open networking summit team originally composed linux foundation onos project pmc-sierra sckipio started 2003 core embedded linux project aims provide vendor-neutral place establish core embedded linux technologies beyond linux foundation projects start linux foundation member company allowed apply membership core embedded linux project announced wake heartbleed fund support free open-source software projects critical functioning internet diamon workgroup works toward improving interoperability open source tools improve linux-based tracing profiling logging monitoring features according workgroup diamon aims accelerate development making easier work together common pieces data plane development kit consists libraries accelerate cpu architecture-running packet processing workloads according intel dpdk improve packet processing performance ten times started 2014 dronecode began open source collaborative project unite current future open source drone initiatives auspices linux foundation goal common shared open source stack unmanned aerial vehicles uavs chris anderson ceo 3d robotics founder diy drones serves chairman board directors lorenz meier creator px4 mavlink qgc pixhawk serves community representative board founded 2017 edgex foundry acts vendor-neutral interoperability framework hosted hardware os agnostic reference platform seeks enable ecosystem plug-and-play components uniting marketplace accelerating iot deployment project wants enable collaborators freely work open interoperable iot solutions existing self-created connectivity standards fast data project-referred fido provides io services framework next wave network storage software stack fd.io universal data plane fd.io runs completely user space said ed warnicke consulting engineer cisco chair fd.io technical steering committee fossology primarily project dedicated open source license compliance software system toolkit users able run licenses copyright export control scans command line database web ui provided compliance workflow frrouting frr ip routing protocol suite unix linux platforms incorporates protocol daemons bgp is-is ldp ospf pim rip hyperledger project global open source effort based around advancing cross-industry blockchain technologies addition hosted linux foundation backed finance banking iot supply chain manufacturing technology leaders project foundation fastest growing date boasting 115 members since founding 2016 may 2016 co-founder apache software foundation brian behlendorf joined project executive director io visor open source project community developers enable new way innovate develop share io networking functions advance io networking technologies address new requirements presented cloud computing internet things iot software-defined networking sdn network function virtualization nfv iotivity oss framework enabling seamless device-to-device connectivity aid internet things grows allseen alliance open connectivity foundation merged october 2016 iot projects alljoyn iotivity respectively continue operating linux foundation two projects collaborate support future versions ocf specification single iotivity implementation janusgraph aims continue open source development titandb graph database fork titandb distributed graph database originally released 2012 enable users find connections among large data sets composed billions vertices edges js foundation previously known jquery foundation according by-laws jsfoundation inc aims help development adoption important javascript technology foundation works facilitate collaboration within javascript development community foster javascript applications server-side projects providing best practices policies 2016 dojo foundation merged jquery foundation subsequently rebranded js foundation became linux foundation project notable projects supported js foundation include node-red appium jquery dojo toolkit qunit eslint grunt 2019 js foundation merged node.js foundation form new openjs foundation stated mission foster healthy growth javascript web ecosystem whole kinetic open storage project dedicated creating open source standard around ethernet-enabled key/value kinetic devices accessing drives creating standard expands available ecosystem software hardware systems developers project result alliance including major hard drive manufacturers- seagate toshiba western digital- addition cisco cleversafe dell digitalsense netapp open vstorage red hat scality linux standard base lsb joint project several linux distributions organizational structure linux foundation standardize software system structure filesystem hierarchy used linux operating system lsb based posix specification single unix specification several open standards extends certain areas according lsb lsb compliance may certified product certification procedure lsb specifies example standard libraries number commands utilities extend posix standard layout file system hierarchy run levels printing system including spoolers cups tools like foomatic several extensions x window system ltsi project created/supported hitachi lg electronics nec panasonic qualcomm atheros renesas electronics samsung electronics sony toshiba hosted linux foundation aims maintain common linux base use variety consumer electronics products similar linux foundation overall mission encouraging widespread adoption linux open source technology node.js foundation exists primarily accelerate development node.js platform foundation also operates open governance model heighten participation amongst vendors developers general node.js community structure gives enterprise users assurance innovation continuity without risk since launching 2015 foundation seen strong growth resulting new initiatives node security platform tool allowing continuous security monitoring node.js apps node interactive series professional conferences aimed today average node.js user node.js reports 3.5 million users annual growth rate 100 percent foundation among linux foundation fastest growing projects 2019 node.js foundation merged js foundation form new openjs foundation.. stated mission foster healthy growth javascript web ecosystem whole odpi hosts open source projects accelerate development delivery big data solutions.. aims deliver well-defined open source open data technologies run across distributed devices promotes technologies worldwide certification programs forms marketing onos open network operating system open source community mission bringing promise software-defined networking sdn communications service providers order make networks agile mobile data center applications better economics users providers oai committed standardizing rest apis described smartbear software donated swagger specification directly initiative new name specification openapi specification openbmc project collaborative open-source project whose goal produce open source implementation baseboard management controllers bmc firmware stack openchain project centered around managing enterprise compliance open source supply chains generally project described community effort establish best practices effective management open source software compliance 2015 docker coreos launched oci partnership linux foundation create set industry standards open around container formats runtime opendaylight leading open sdn platform aims accelerate adoption software-defined networking sdn network functions virtualization nfv service provider enterprise research networks openjs foundation founded 2019 merger js foundation node.js foundation stated mission foster healthy growth javascript web ecosystem providing neutral organization host projects collaboratively fund activities benefit ecosystem whole openjs foundation made 29 open source javascript projects including appium dojo jquery node.js webpack founding members included google microsoft ibm paypal godaddy joyent open mainframe project aims drive harmony across mainframe community developed shared tool sets resources project also endeavors heighten participation academic institutions educating mainframe linux engineers developers openmama open middleware agnostic messaging api lightweight vendor-neutral integration layer systems built top variety message-oriented middleware announced october 2017 goal openmessaging act vendor-neutral open standard distributed messaging/stream project supported alibaba verizon oath business unit others openprinting workgroup website belonging linux foundation provides documentation software support printing linux formed linuxprinting.org 2006 became part free standards group developed database lists wide variety printers various manufacturers database allows people give report support quality printer also give report support given linux printer vendor also created foomatic formerly cupsomatic script plugs common unix printing system cups opensds open source software defined storage controller journalist swapnil bhartiya explained cio formed create industry response address software-defined storage integration challenges goal driving enterprise adoption open standards supported storage users/vendors including dell huawei fujitsu hds vodafone oregon state university originally created nicira moving vmware eventually linux foundation ovs open source virtual switch supporting standard management interfaces protocols open network automation platform result open-o open ecomp projects merging april 2017 platform allows end users design manage automate services virtual functions open platform network function virtualization nfv aims carrier-grade integrated platform introduces new products services industry quickly 2016 project began internship program created working group end user advisory group founded users board pnda platform network data analytics platform scalable network analytics rounding data multiple sources network works apache spark crunch numbers order find useful patterns data effectively r consortium dedicated expanding use r language developing r consortium works r foundation organizations working broaden reach language consortium supported collection tech industry heavyweights including microsoft ibm oracle google esri real-time linux overall goal encouraging widespread adoption real time formed coordinate efforts mainline preempt rt assist maintainers continuing development work long-term support future research rt rethinkdb announced shutdown business linux foundation announced purchased intellectual property cloud native computing foundation project relicensed apache license aslv2 rethinkdb describes first open-source scalable json database built ground realtime web software package data exchange spdx project started 2010 create standard format communicating components licenses copyrights associated software packages part project team curates spdx license list defines list identifiers commonly found licenses exceptions used open source collaborative software streaming network analytics system project snas.io open source framework collect track millions routers peers prefixes routing objects real time snas.io linux foundation project announced may 2017 tizen free open-source standards-based software platform supported leading mobile operators device manufacturers silicon suppliers multiple device categories smartphones tablets netbooks in-vehicle infotainment devices smart tvs todo talk openly develop openly open source collective housed linux foundation helps companies interested open source collaborate better efficiently todo aims reach companies organizations want turn best open source projects programs todo group reaches across industries collaborate open source technical business leaders share best practices tools programs building dependable effective projects long term said jim zemlin collaboration summit 2016 xen project team global open source community develops xen hypervisor contributes linux pvops framework xen® cloud platform xen® arm yocto project open source collaboration project provides templates tools methods help create custom linux-based systems embedded products regardless hardware architecture founded 2010 collaboration among many hardware manufacturers open-source operating systems vendors electronics companies bring order chaos embedded linux development zephyr small real-time operating system connected resource-constrained devices supporting multiple architectures developed open source collaboration project released apache license 2.0 zephyr became project linux foundation february 2016 linux kernel community linux foundation hosts infrastructure organizes conferences linux kernel summit linux plumbers conference also hosts technical advisory board made linux kernel developers one developers appointed sit linux foundation board january 2016 linux foundation announced partnership goodwill central texas help hundreds disadvantaged individuals underserved communities variety backgrounds get training need start new lucrative careers linux fund deserving developers accelerate technical problem solving collaboration open source community linux foundation launched community developer travel fund sponsorships open elite community developers proven track record open source development achievement get funding attend technical events employers applications available core infrastructure initiative cii project managed linux foundation enables technology companies industry stakeholders esteemed developers collaboratively identify fund critical open source projects need assistance june 2015 organization announced financial support nearly 500,000 three new projects better support critical security elements global information infrastructure may 2016 cii launched best practice badge program raise awareness development processes project governance steps help projects better security outcomes may 2017 cii issued 100th badge passing project linux foundation open compliance program provides array programs open source software compliance focus initiative educate assist developers companies license requirements order build programs without friction program consists primarily self-administered training modules also meant include automated tools help programmatically identify license compliance issues june 2018 1000 members identify ideals mission linux foundation projects 500 silver members actively donate linux foundation funding linux foundation comes primarily platinum members paying us 500,000 per year according schedule lf bylaws adding us 4 million gold members contribute combined total us 1.6 million smaller members less april 2014 foundation collects annual fees worth least 6,245,000 usd linux foundation uses funds help fund infrastructure fellows including linus torvalds help develop linux kernel december 2018 100 donations received go towards funding diversity programs according organization web site linux foundation events creators maintainers practitioners important open source projects meet linux foundation events 2017 attract nearly 25,000 developers maintainers system administrators thought leaders business executives industry professionals 4,000 organizations across 85 countries many open source projects also co-locate events linux foundation events take advantage cross-community collaboration projects industry 2017 events cover various trends open source including big data cloud native containers iot networking security
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Operating systems
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high throughput file system high throughput file system htfs journaling file system used current versions sco openserver successor eafs
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Computer file systems
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genieo genieo innovation israeli company specializing unwanted software includes advertising user tracking software commonly referred potentially unwanted program adware privacy-invasive software grayware malware best known genieo application type also operate installmac distributes additional 'optional search modifying software applications 2014 genieo innovation acquired 34 million somoto another company bundles legitimate applications offers additional third party applications may unwanted user sector israeli software industry frequently referred download valley genieo innovation founded april 2008 sol tzvi jacob tenenboem first version genieo released september 2009 beta version launched demo2010 conference march 2010 genieo website suspected changed name inkeepr software installs onto computers makes almost impossible users remove hijacks user browser tracks browser usage intention mining information users complain acts like virus need run special programs remove genieo listed malware apple inc. xprotect anti-malware service built macintosh computers running mac os x snow leopard later may 2013 malicious installer distributed genieo partner softonic found security software company intego installer masquerades necessary update adobe flash player attempts install genieo.app without user interaction dynamic libraries added safari browser intercept searches intended bing google versions genieo mac also offered 'codecs required video playback testing carried genieo mac june 2013 found left active software behind using supplied uninstaller required detailed manual removal november 2013 another fake application installer reported include genieo adware january 2014 sophos added genieo mac threat list category viruses spyware trojan horse computing adware november 2014 genieo mac flagged intego mentioned according analysis virustotal 25 55 surveyed anti-malware solutions including ad-aware avast bitdefender comodo dr web eset fortinet f-secure kaspersky trend micro housecall sophos symantec july 2014 genieo acquired 34 million somoto another company bundles legitimate applications offers additional third party applications may unwanted user august 2015 malware researchers discovered genieo installer acquired access mac keychain automated click allow permission dialog keychain displayed code safari browser extension added genieo also contained immediately used earlier versions installer april 2019 osx.genieo locked user macbook air computer passwords stored secure note found missing mail account settings tampered genieo case became impetus rapid emergence similar adware search macshop ads macvx etc
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Computer security
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hpcx hpcx supercomputer actually cluster ibm eserver p5 575 high-performance servers located daresbury laboratory cheshire england supercomputer maintained hpcx consortium uoe hpcx ltd led university edinburgh epcc science technology facilities council ibm project funded epsrc hpcx service ended january 2010
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Distributed computing architecture
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electronic seal electronic seal piece data attached electronic document data ensures data origin integrity term used eu regulation 910/2014 eidas regulation electronic transactions within internal european market conceptually similar electronic signatures usually technically realized digital signatures electronic seals serve evidence electronic document issued specific legal entity purpose electronic seal must linked data sealed way subsequent change data detectable also way fake seal created without access data usually private key used creation digital seal usually achieved use qualified digital certificate involved creation digital seal unique private key used creation digital seal ensures non-repudiation entity created digital seal later deny created seal document document modified digital seal created digital seal valid modified document checked anyone access public key corresponding private key used creation digital seal ensuring integrity sealed document besides authenticating document issued legal entity e-seals also used authenticate digital asset legal person software code servers important difference digital signature electronic seal latter usually created legal person digital signatures created natural person creation digital signature action person signing document data required contrast creation digital seals automatised incorporated processes executed automatically digital environment qualified electronic seal electronic seal compliant eu regulation 910/2014 eidas regulation electronic transactions within internal european market enables verify issuer document long periods time qualified electronic seals considered digital equivalent seals legal entities paper according eidas regulation qualified electronic seal must created qualified electronic device based qualified certificate electronic seal
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Computer security
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medical device hijack medical device hijack also called medjack type cyber attack weakness target medical devices hospital covered extensively press 2015 2016 medjack received additional attention 2017 function increase identified attacks globally research released early year hijacks may endanger patients remote control critical devices theft sensitive data medjack.3 seems additional sophistication designed reveal searches older vulnerable operating systems found embedded within medical devices ability hide sandboxes defense tools safe non vm environment considerable discussion debate topic rsa 2017 event special session medjack.3 debate ensued various medical device suppliers hospital executives audience vendors ownership financial responsibility remediate massive installed base vulnerable medical device equipment notwithstanding discussion fda guidance well intended may go far enough remediate problem mandatory legislation part new national cyber security policy may required address threat medjack sophisticated attacker tools used hospitals new variants ransomware seem targeted hospitals cyberattack attacker places malware within networks variety methods malware laden website targeted email infected usb stick socially engineered access etc malware propagates within network time existing cyber defenses clear attacker tools standard serves workstations endpoints cyber defense software access embedded processors within medical devices embedded operating systems within medical devices running microsoft windows 7 windows xp security operating systems longer supported relatively easy targets establish attacker tools inside medical devices cyber attacker finds safe harbor establish backdoor command control noted since medical devices fda certified hospital cyber security team personnel access internal software without perhsp incurring legal liability impacting operation device violating certification given open access medical devices penetrated attacker free move laterally discover targeted resources ss patient data quietly identified exfiltrated organized crime targets healthcare networks order access steal patient records virtually medical device impacted attack one earliest documented examples testing identified malware tools blood gas analyzer magnetic resonance imaging mri system computerized tomogram ct scan xray machines 2016 case studies became available showed attacker presence also centralized pacs imaging systems vital important hospital operations attack primarily centers largest 6,000 hospitals global basis healthcare data highest value stolen identity data given weakness security infrastructure within hospitals creates accessible highly valuable target cyber thieves besides hospitals impact large physician practices accountable care organizations acos independent physician associations ipas skilled nursing facilities snfs acute care long term surgical centers diagnostic laboratories many reports hospitals hospital organizations getting hacked including ransomware attacks windows xp exploits viruses data breaches sensitive data stored hospital servers various informal assessments estimated medjack currently impacts majority hospitals worldwide remains undetected bulk technologies necessary detect medjack lateral movement attackers command control within targeted medical devices installed great majority hospitals time 3.2.2017 statistic would note hospital 500 beds roughly 15 medical devices usually internet things iot connected per bed addition centralized administration systems hospital diagnostic labs utilized medical devices emr/ehr systems ct/mri/x-ray centers within hospital attacks hard detect even harder remediate deception technology evolution automation honeypot honeygrid networks trap lure attackers move laterally within networks medical devices typically must software reloaded manufacturer hospital security staff equipped able access internals fda approved devices become reinfected quickly takes one medical device potentially re-infect rest hospital 28 december 2016 us food drug administration released recommendations legally enforceable medical device manufacturers maintain security internet-connected devices
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Computer security
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power7 power7 family superscalar symmetric multiprocessors based power isa 2.06 instruction set architecture released 2010 succeeded power6 power7 developed ibm several sites including ibm rochester mn austin tx essex junction vt t. j. watson research center ny bromont qc ibm deutschland research development gmbh böblingen germany laboratories ibm announced servers based power7 8 february 2010 ibm 244 million darpa contract november 2006 develop petascale supercomputer architecture end 2010 hpcs project contract also states architecture shall available commercially ibm proposal percs productive easy-to-use reliable computer system contract based power7 processor aix operating system general parallel file system one feature ibm darpa collaborated modifying addressing page table hardware support global shared memory space power7 clusters enables research scientists program cluster single system without using message passing productivity standpoint essential since scientists conversant mpi parallel programming techniques used clusters power7 superscalar symmetric multiprocessor architecture substantial evolution power6 design focusing power efficiency multiple cores simultaneous multithreading smt power6 architecture built ground maximize processor frequency cost power efficiency achieved remarkable 5 ghz power6 features dual-core processor capable two-way simultaneous multithreading smt ibm power 7 processor eight cores four threads per core total capacity 32 simultaneous threads ibm stated isca 29 peak performance achieved high frequency designs 10–20 fo4 delays per pipeline stage cost power efficiency however power6 binary floating-point unit achieves 6-cycle 13-fo4 pipeline therefore pipeline power7 cpu changed power5 power6 designs respects rework similar intel turn 2005 left p4 7th-generation x86 microarchitecture power7 superscalar symmetric multiprocessor available 4 6 8 physical cores per microchip 1 32-way design 1024 smts slightly different microarchitecture interfaces supporting extended/sub-specifications reference power isa and/or different system architectures example supercomputing hpc system power 775 packaged 32-way quad-chip-module qcm 256 physical cores 1024 smts also special turbocore mode turn half cores eight-core processor 4 cores access memory controllers l3 cache increased clock speeds makes core performance higher important workloads require fastest sequential performance cost reduced parallel performance turbocore mode reduce software costs half applications licensed per core increasing per core performance software new ibm power 780 scalable high-end servers featuring new turbocore workload optimizing mode delivering double performance per core power6 based systems core capable four-way simultaneous multithreading smt power7 approximately 1.2 billion transistors 567 mm large fabricated 45 nm process notable difference power6 power7 executes instructions out-of-order instead in-order despite decrease maximum frequency compared power6 4.25 ghz vs 5.0 ghz core higher performance power6 processor 4 times number cores power7 specifications power7 processor core implements aggressive out-of-order ooo instruction execution drive high efficiency use available execution paths power7 processor instruction sequence unit capable dispatching six instructions per cycle set queues eight instructions per cycle issued instruction execution units power7 processor set twelve execution units described gives following theoretical single precision sp performance figures based 4.14 ghz 8 core implementation 4 64-bit simd units per core 128-bit simd vmx unit per core 12 multiply-adds per cycle giving 24 sp fp ops per cycle 4.14 ghz gives 4.14 billion 24 99.36 sp gflops 8 cores 794.88 sp gflops peak double precision dp performance roughly half peak sp performance comparison latest microarchitecture intel haswell came 3 years later power7 16 dp flops 32 sp flops per cycle 8/16 dp/sp fused multiply-add spread across 2× 256 bit avx2 fp vector units 3.4 ghz i7-4770 translates 108.8 sp gflops per core 435.2 sp gflops peak performance across 4-core chip giving roughly similar levels performance per core without taking account effects benefits intel turbo boost technology theoretical peak performance comparison holds practice power7 i7-4770 obtaining similar scores spec cpu2006 floating point benchmarks single-threaded 71.5 power7 versus 74.0 i7-4770 notice power7 chip significantly outperformed 2×–5× i7 benchmarks bwaves cactusadm lbm also significantly slower 2x-3x others indicative major architectural differences two chips mainboards memory systems etc designed different workloads mind however overall broad sense one say floating-point performance power7 similar haswell i7 ibm introduced power7+ processor hot chips 24 conference august 2012 updated version higher speeds cache integrated accelerators manufactured 32 nm fabrication process first boxes ship power7+ processors ibm power 770 780 servers chips 80 mb l3 cache 10 mb/core improved clock speeds 4.4 ghz 20 lpars per core range power7 systems includes express models 710 720 730 740 750 enterprise models 770 780 795 high performance computing models 755 775 enterprise models differ capacity demand capabilities maximum specifications shown table ibm also offers 5 power7 based bladecenters specifications shown table following supercomputer projects use power7 processor
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Computer architecture
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australian research data commons australian research data commons ardc limited company formed 1 july 2018 combining australian national data service ands nectar national eresearch collaboration tools resources research data services rds purpose enable australian researchers industry access nationally significant einfrastructure skills platforms data collections ands established 2008 order help address challenges storing managing making accessible australia research data joint collaboration monash university australian national university csiro manages research data australia web portal enables access data 100 australian research organisations cultural institutions government agencies nectar established 2009 australian government project directorate establish infrastructure university melbourne created 2011 research data services project provides service development prioritised areas research continuing operational support infrastructure accesses data national collections project led monash university collaboration australian national university anu csiro created basis full ands implementation aim allow researchers identify locate access analyse available research data transforming large number scattered disparate collections around australia cohesive accessible body resources importance eresearch infrastructure australian future research competitiveness emphasised prime reason funding provided australian government national collaborative research infrastructure strategy ncris part funding agreement department innovation industry science research diisr monash university september 2008 mid-2009 ands funded education investment fund eif establishment australian research data commons australian government ’ super science initiative research data australia formerly ands collections registry ands significant service web portal enables access data 100 australian research organisations cultural institutions government agencies online research collections australia orca registry software utility drove ands collections registry precursor research data australia used names online discovery service run ands allows researchers publicise existence research data enables prospective users data find research data australia made use iso 2146-based rif-cs metadata standard research data services project continuation research data storage infrastructure rdsi national collaboration tools resources project nectar established 2009 australian government budget part super science initiative financed education investment fund eif since received government funding well similar investment australian universities research institutions project got ground 2011 university melbourne partners research communities develop manage 12 virtual laboratories 16 e-research tools national research cloud known nectar cloud 10,000 users three organisations created aligned set investments business plans 2017/8 order integrate work line 2016 national research infrastructure ncris roadmap created department education training monash university remains lead agent ands university queensland lead agent rds university melbourne lead agent nectar
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Databases
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gekko optimization software gekko python package solves large-scale mixed-integer differential algebraic equations nonlinear programming solvers ipopt apopt bpopt snopt minos modes operation include machine learning data reconciliation real-time optimization dynamic simulation nonlinear model predictive control addition package solves linear programming lp quadratic programming qp quadratically constrained quadratic program qcqp nonlinear programming nlp mixed integer programming mip mixed integer linear programming milp gekko available python installed pip pypi python software foundation gekko works platforms python 2.7 3+ default problem sent public server solution computed returned python windows macos linux arm raspberry pi processor options solve without internet connection gekko extension apmonitor optimization suite integrated modeling solution visualization directly within python mathematical model expressed terms variables equations hock schittkowski benchmark problem 71 used test performance nonlinear programming solvers particular optimization problem objective function formula_1 subject inequality constraint formula_2 equality constraint formula_3 four variables must lower bound 1 upper bound 5 initial guess values formula_4 optimization problem solved gekko shown applications include cogeneration power heat drilling automation severe slugging control solar thermal energy production solid oxide fuel cells flow assurance enhanced oil recovery essential oil extraction unmanned aerial vehicles uavs many references apmonitor gekko sample types applications solved gekko developed national science foundation nsf research grant 1547110 detailed special issue collection combined scheduling control notable mentions gekko listing decision tree optimization software added support apopt bpopt solvers projects reports online dynamic optimization course international participants gekko topic online forums users solving optimization optimal control problems gekko used advanced control temperature control lab tclab process control education 20 universities one application machine learning perform regression training data build correlation example deep learning generates model training data generated function formula_5 artificial neural network three layers used example first layer linear second layer hyperbolic tangent activation function third layer linear program produces parameter weights minimize sum squared errors measured data points neural network predictions points gekko uses gradient-based optimizers determine optimal weight values instead standard methods backpropagation gradients determined automatic differentiation similar popular packages problem solved constrained optimization problem converged solver satisfies karush–kuhn–tucker conditions using gradient-based optimizer allows additional constraints may imposed domain knowledge data system neural network model tested across range training data well extrapolation demonstrate poor predictions outside training data predictions outside training data set improved hybrid machine learning uses fundamental principles available impose structure valid wider range conditions example hyperbolic tangent activation function hidden layer 2 could replaced sine cosine function improve extrapolation final part script displays neural network model original function sampled data points used fitting optimal control use mathematical optimization obtain policy constrained differential formula_6 equality formula_7 inequality formula_8 equations minimizes objective/reward function formula_9 basic optimal control solved gekko integrating objective transcribing differential equation algebraic form orthogonal collocation finite elements
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Programming language topics
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techila grid techila distributed computing engine earlier known techila grid commercial grid computing software product speeds simulation analysis computational applications enabling scalability across resources user on-premises data center user cloud account techila distributed computing engine developed licensed techila technologies ltd privately held company headquartered tampere finland product also available on-demand solution google cloud launcher online marketplace created operated google according idc solution enables organizations create hpc infrastructure without major capital investments operating expenses required new hpc hardware techila distributed computing engine distributed computing middleware management solution used access manage on-premises cloud resources various high-performance computing hpc computing uses including high-throughput computing htc scenarios creates scalable computing service execution environment also support applications deployed within production environments technology techila distributed computing engine built autonomic computing architecture patented techila technologies enabled features automated system management fault tolerance simplify deployment use administration large-scale distributed computing systems techila distributed computing engine includes techila distributed computing engine set limitations physical location distance computing resources used system product description techila distributed computing engine lists three supported system designs techila technologies offers also tools enable automated provisioning integration cloud-based resources grid techila server java-based software product optimizes performance techila distributed computing engine environment jobs optimization done techila server supports large jobs also makes system suitable running small computational jobs performance techila distributed computing engine different scenarios evaluated thesis tampere university technology originally techila server delivered embedded appliance embedded appliance product discontinued 2012 currently techila server delivered either virtual appliance using cloud-specific deployment tools techila worker software agent must installed computer participate techila distributed computing engine environment computers physical virtualized computers running hypervisor cloud virtual machine techila distributed computing engine supports following public cloud services microsoft azure amazon ec2 amazon elastic compute cloud google compute engine techila worker software installed computer authenticate computer techila server using certificate system use self-management automatically configure computer run jobs received techila server techila worker java-based client middleware component run microsoft windows linux client computers participating techila distributed computing engine system different hardware software platforms techila worker software runs lowest possible priority computer techila worker also interoperable batch-queuing systems like slurm torque oracle grid engine previously known sun grid engine sge interoperability allows existing hpc users use existing infrastructures part techila distributed computing engine system without techila worker interfering system techila sdk earlier known techila grid management kit techila gmk library software components connect applications techila distributed computing engine environment sdk includes plug-ins many commonly used research development tools languages matlab r python perl java c .net c/ c++ fortran command-line interface script applications developed using application programming interfaces techila sdk also deployed within production environments run service soa environment techila sdk supports windows linux operating systems web-based administrator user interface provides administrators simplified easy-to-use interface techila server administrator user interface allows monitoring system activity view control job execution execution policy monitor control techila workers techila worker groups control security settings manage users techila technologies says development techila distributed computing engine technology started initially vision grid computing enablement fast simulation analysis without complexity traditional high-performance computing security techila distributed computing engine evaluated nixu ltd 2008 nixu finland largest specialist company information security consulting many global corporates customers techila distributed computing engine accepted security-sensitive industry sectors finance insurance engineering pharmaceutical techila distributed computing engine demonstrated research team university helsinki 2011 capable providing autonomic management computing environments large numbers windows azure cloud instances university helsinki also demonstrated techila distributed computing engine ability enhance usability utilization large-scale cluster resources projects implemented using matlab r python java c/ c++/ c techila distributed computing engine system computational resources arranged device groups organizational security compliance administrative control despite performance large-scale systems csc center science also suitable smaller environments tutgrid utilizes idle capacity desktop pcs computers tampere university technology tut scientific computing
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Distributed computing architecture
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jose duato josé francisco duato marín alberic valencia 1958 spanish professor researcher awarded national prize research julio rey pastor 2009 king jaime prize new technologies 2006 research based mainly field interconnection networks develops role full professor department computer engineering disca polytechnic university valencia first author book interconnection networks engineering approach published united states ieee computer society press 1997 morgan kaufmann 2002 quoted book interconnection networks existence today 1400 citations used engineers designing interconnection networks market-leading companies ibm compaq intel sun microsystems provide doctoral programs especially united states co-author chapter interconnection networks fourth edition book computer architecture quantitative approach john hennessy dave patterson widely used cited book computer architecture available today 8000 citations total 2009 prof. duato received prestigious national award “ julio rey pastor “ field mathematics information technologies communications contributions international importance field interconnection networks transference results industry
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Computer architecture
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united states v. fricosu united states v. fricosu 841 f.supp.2d 1232 d. col 2012 federal criminal case colorado addressed whether person compelled reveal encryption passphrase password despite u.s. constitution fifth amendment protection self-incrimination january 23 2012 judge robert e. blackburn held writs act fricosu required produce unencrypted hard drive fricosu attorney claimed possible remember password month later fricosu ex-husband handed police list potential passwords one passwords worked rendering self-incrimination issue moot electronic frontier foundation filed amicus brief support fricosu fricosu subsequently entered plea agreement 2013 meaning question defendant right resist mandatory decryption addressed higher court time future case addressing issue arises
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Computer file systems
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code shikara code shikara hassan arshad computer worm related dorkbot family attacks social engineering 2011 code first identified danish cyber security company csis av-company sophos reported november 2011 threat mainly spreads malicious links social network facebook 2013 bitdefender labs caught blocked worm capable spying users browsing activities meanwhile stealing personal online/offline information and/or credentials commonly known cybercrime infection originally flagged online backup service mediafire detected worm distributed camouflaged image file despite misleading extension mediafire successfully identified malicious image .exe-file malicious shikara code poses .jpeg image indeed executable file irc bot malware simply integrated attackers control command server besides stealing usernames passwords bot herder may also order additional malware downloads mediafire taken steps address incorrect misleading file extensions update identifies displays short description identifying specific file types help users specific threat file sharing service also blocks files double extensions .jpg.exe .png.exe .bmp.exe like usual malware backdoor.ircbot.dorkbot update installed victim computer related devices biggest risk someone facebook contacts may account already compromised due sloppy password security granting access rogue application account user allured clicking link seemingly posted one friends although links pretend point image truth malicious screensaver hidden behind icon two blonde women code launched attempts download malicious software hosted specific compromised israeli domain malware currently present israeli website remains message seemingly intruders says likely using additional websites continuing spreading cyber attack popular baits tricking users click malicious links include rihanna taylor swift sex tapes
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Computer security
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gowarrior gowarrior open-source community-supported computing platform gowarrior designed world makers hackers educators hobbyists newbies build electronics projects offers complete package hardware software cloud service tiger board single-board computer performs hardware gowarrior platform contains arm cortex a9 based m3733-afaaa soc arm mali-400 mp2 well integrated 1gb ddr3 ram gowarrior specifications godroid android kitkat 4.4.4. based optimized operating system gowarrior platform addition original android functionalities godroid pre-integrates useful middleware components libraries well self-developed function blocks makes also software development kit android applications godroid supports booting nand flash microsd card contains boot code image files replacing android native media engine stagefright gstreamer utilizing hardware acceleration facilities godroid supports various audio/video/container hardware decoding multiple network protocols including microsoft smooth streaming http live streaming kodi 14.2 variety supported video/audio plug-ins besides screen mirroring function android miracast godroid also implements dlna system service sharing digital media among multimedia devices dmr dms dmp supported addition c/c++/java godroid also integrates qpython2engine python2 programming android tiger board provides 2 sets 40-pin expansion headers one compatible raspberry pi connector raspberry pi python applications ported run godroid godroid supports android studio application ide api level 19 configuration match godroid provides availability original android api also proprietary extended api gpio/ic2/spi/pwm godroid supports standard adb debugging via ethernet wi-fi usb gobian linux-embedded operating system running tiger board gowarrior platform gobian developed based raspbian debian 7 wheezy armhf differs raspbian extra features example gobian encapsulates rpi.gpio i/o libraries facilitate transplanting projects use related libraries raspberry pi tiger board furthermore gobian provides support multimedia integrating gof kodi middle-ware modules applications out-of-the-box gobian enables internet connection ethernet wi-fi ethernet port wi-fi module tiger board thus supports various methods access projects transfer data ftp ssh gobian automatically synchronizes system time internet time servers using ntp protocol gobian integrates built-in file system data management c c++ python perl shell script gobian lets call gpio/i2c/uart/spi interfaces directly projects built-in rpi.gpio libraries gobian makes easy secondary development multimedia applications customized gof middle-ware tiger board on-board m3733-afaaa processor makes gobian multitasking system good performance software programs available debian basically compatible gobian gobian supports ultra-power-saving sleep mode pmu standby entire board power consumption low 0.35w gobian integrates dlna fully support multimedia sharing multi-screen interaction gowarrior community already launched support projects gobian cloudq comprehensive back-end community support help users easily build projects
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Computer architecture
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alain colmerauer alain colmerauer 24 january 1941 – 12 may 2017 french computer scientist professor aix-marseille university creator logic programming language prolog alain colmerauer born 24 january 1941 carcassonne graduated grenoble institute technology earned ph.d. ensimag grenoble colmerauer spent 1967–1970 assistant professor university montreal created q-systems one earliest linguistic formalisms used development taum-meteo machine translation prototype developing prolog iii 1984 one main founders field constraint logic programming colmerauer became associate professor aix-marseille university luminy 1970 promoted full professor 1979 1993 1995 head laboratoire d'informatique de marseille lim joint laboratory centre national de la recherche scientifique university de provence university de la mediterranee despite retiring emeritus professor 2006 remained member artificial intelligence taskforce luminy colmerauer award regional council provence-alpes-côte d'azur 1985 michel monpetit award french academy sciences 1986 made knight legion honour french government became fellow american association artificial intelligence 1991 received acp research excellence award principles practice constraint programming 2008 also correspondent french academy sciences area mathematics colmerauer died 12 may 2017
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Programming language topics
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cluster-aware application cluster-aware application software application designed call cluster apis order determine running state case manual failover triggered cluster nodes planned technical maintenance automatic failover required computing cluster node encounters hardware software failure maintain business continuity cluster-aware application may capable failing lan wan
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Distributed computing architecture
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february 2010 australian cyberattacks february 2010 australian cyberattacks series denial-of-service attacks conducted anonymous online community australian government response proposed web censorship regulations operation titstorm name given cyber attacks perpetrators resulted lapses access government websites 10 11 february 2010 accompanied emails faxes phone calls harassing government offices actual size attack number perpetrators involved unknown estimated number systems involved ranged hundreds thousands amount traffic caused disruption multiple government websites australian telecommunications minister stephen conroy proposed regulations would mainly filter sites pornographic content various groups advocating uncensored access internet along companies like google yahoo object proposed filter spokesperson conroy said actions legitimate form protest called irresponsible attacks also drew criticism filter protest groups initial stage followed small in-person protests 20 february called project freeweb attack began protest responding plan australian telecommunications minister stephen conroy would require internet service providers block australian users accessing illegal government deemed unwanted content websites blocked feature pornography showing rape bestiality child sex abuse small-breasted women may appear legal age female ejaculation drawn depictions acts included proposal proposed filter also includes gambling sites along others showing drug use leaked version proposed blacklist also referred refused classification rc list also showed sites include adult content name operation titstorm reference material would censored google questioned proposal saying prohibitions would broad strongly opposed free speech groups poll conducted mcnair ingenuity research hungry beast television program found 80 1,000 respondents favour concept plan survey also found 91 concerned government intent keep list filtered websites secret department defence cyber security operations centre discovered attack coming 5 february statement released anonymous press two days attack said government right refuse citizens access information solely perceive 'unwanted went read australian government learn one mess porn one messes access perfectly legal illegal content reason anonymous previously garnered media attention protests church scientology project chanology iranian government september 2009 prime minister kevin rudd website hacked similar protest proposed web censorship reforms flyers distributed recruit participants said attack begin 8 pm aest 10 february day government websites targeted denial-of-service attacks communications department said hackers infiltrated government security instead swamped government computer servers sites left unavailable sporadic periods throughout attack one point australian parliament website offline two days due high volume requests rudd government site also inaccessible time primary target communications department also received large amount traffic government offices also flooded e-mail spam junk faxes prank phone calls prime minister homepage vandalized pornographic images flyer released attack called faxes focus cartoon pornography female ejaculation small-breasted pornography reports actual size attack varied one cyber security expert described attacks equivalent parking truck across driveway shopping centre firm marketing security technology said peak attack relatively low 16.84 megabits per second one writer described 7.5 million requests per second initially brought parliament website massive site usually receives hundred per second appears botnets made compromised computers used estimates number attacking systems involved ranged hundreds thousands spokeswoman conroy said attacks legitimate political protest according totally irresponsible potentially deny services australian public systems administrators guild australia said condemned ddos attacks wrong way express disagreement proposed law anti-censorship groups criticised attacks saying hurt cause purported spokesperson attackers recommended wider australian public protest filter signing petition electronic frontiers australia anonymous coordinated second phase small protests outside parliament house canberra major cities throughout australia 20 february additional demonstrations held country embassies overseas organizers called follow-up protests project freeweb differentiate criticised cyber attacks several supporters attack later said messageboard taking websites enough convince government back web filtering policy called violence others disagreed actions proposed launching additional attack popular government site spokesman electronic frontiers australia said believed real intention capacity follow violent threats attack also resulted criticism australia terrorism laws university new south wales law journal one writer wrote provisions leave place legitimate acts online protest least sets penalty far high relatively minor cyber-vandalism australian teenager charged four counts inciting hackers impair electronic communications two unauthorised access restricted data role attack ordered pay bond instead convicted pleading guilty showing good behaviour july 2010 conroy delayed implementing plan pending 12-month review refused classification content rated proposal expected go forward due opposition coalition greens internet service providers telstra optus agreed voluntarily block content
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Computer security
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conceptual dependency theory conceptual dependency theory model natural language understanding used artificial intelligence systems roger schank stanford university introduced model 1969 early days artificial intelligence model extensively used schank students yale university robert wilensky wendy lehnert janet kolodner schank developed model represent knowledge natural language input computers partly influenced work sydney lamb goal make meaning independent words used input i.e two sentences identical meaning would single representation system also intended draw logical inferences model uses following basic representational tokens set conceptual transitions act representation e.g atrans used represent transfer give take ptrans used act locations move go mtrans represents mental acts tell etc sentence john gave book mary represented action atrans two real world objects john mary
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Computational linguistics
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sysquake sysquake numerical computing environment based programming language mostly-compatible matlab offers facilities interactive graphics give insights problems analyzed used teaching research engineering sysquake supports two kinds codes libraries collections related functions extend sysquake capabilities sq files applications interactive graphics menus sysquake pro also extended plugins several applications share large part sysquake code libraries usually compatible applications
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Programming language topics
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explicit data graph execution explicit data graph execution edge type instruction set architecture isa intends improve computing performance compared common processors like intel x86 line edge combines many individual instructions larger group known hyperblock hyperblocks designed able easily run parallel parallelism modern cpu designs generally starts plateau eight internal units one four cores edge designs intend support hundreds internal units offer processing speeds hundreds times greater existing designs major development edge concept led university texas austin darpa polymorphous computing architectures program stated goal producing single-chip cpu design 1 tflops performance 2012 yet realized 2018 almost computer programs consist series instructions convert data one form another instructions require several internal steps complete operation time relative performance cost different steps changed dramatically resulting several major shifts isa design 1960s memory relatively expensive cpu designers produced instruction sets densely encoded instructions data order better utilize resource instance codice_1 instruction would provided many different forms would gather b different places main memory indexes registers providing different instructions allowed programmer select instruction took least possible room memory reducing program needs leaving room data instruction set tried provide every possible access mode every possible instruction like dec vax known orthogonal considered paragon design style memory access wide variety modes led instruction sets hundreds different instructions style known today cisc complex instruction set computing late 1970s memory become cheap cost lower performance cpu designs ran many times faster memory talked new regime orthogonality became undesirable versions instructions took room cpu little nothing improve performance communicated slow memory time memory savings unnecessary period risc reduced instruction set computing design philosophy flourished basic aim reduce access memory much possible using internal high-performance registers instructions side-effect wide variety different modes instructions disappeared might one codice_2 instruction instead many removing instructions reduced complexity instruction decoder freed considerable space cpu space used greatly increase number registers 1990s chip design fabrication process grew point possible build commodity processor every potential feature built improve performance cpu designs started adding internal parallelism becoming superscalar program instructions work unrelated data adding functional units instructions run time new portion cpu scheduler looks independent instructions feeds units taking outputs re-ordering externally appears ran succession amount parallelism extracted superscalar designs limited number instructions scheduler examine interdependencies examining greater number instructions improve chance finding instruction run parallel cost increasing complexity scheduler despite massive efforts cpu designs using classic risc cisc isa plateaued three four functional units additional performance wrung systems examining instructions find ones operate different types data adding units dedicated sort data led introduction floating point units recently single instruction multiple data simd units drawback approach makes cpu less generic feeding cpu program uses almost floating point instructions instance bog fpus units sit idle recent problem modern cpu designs delay talking registers general terms size cpu die remained largely time size units within cpu grown much smaller units added means relative distance one function unit global register file grown time introduced order avoid delays talking main memory global register file become delay worth avoiding delays talking memory price fell suggested radical change isa instruction set architecture cisc risc designers considering whether problems scaling parallelism increasing delays talking registers demands another switch basic isa among ways introduce new isa long instruction word vliw architectures typified itanium vliw moves scheduler logic cpu compiler much memory longer timelines examine instruction stream static placement static issue execution model works well delays known presence cache latencies filling instruction words proven difficult challenge compiler instruction might take five cycles data cache could take hundreds compiler way know whether data cache runtime determined overall system load factors nothing program compiled key performance bottleneck traditional designs data instructions operate theoretically scattered memory memory performance dominates overall performance classic dynamic placement dynamic issue designs seem reached limit performance capabilities vliw uses static placement static issue model proven difficult master runtime behavior programs difficult predict properly schedule advance edge architectures new class isa based static placement dynamic issue design edge systems compile source code form consisting statically-allocated hyperblocks containing many individual instructions hundreds thousands hyperblocks scheduled dynamically cpu edge thus combines advantages vliw concept looking independent data compile time superscalar risc concept executing instructions data becomes available vast majority real-world programs linkage data instructions obvious explicit programs divided small blocks referred subroutines procedures methods depending era programming language used generally well-defined entrance exit points data passed information lost high level language converted processor much simpler isa information useful modern compilers generalized concept basic block attempting identify within programs optimize memory access registers block instructions control statements predicated instructions dataflow graph encoded using blocks specifying flow data one block instructions another storage area basic idea edge directly support operate blocks isa level since basic blocks access memory well-defined ways processor load related blocks schedule output one block feeds directly one consume data eliminates need global register file simplifies compiler task scheduling access registers program whole instead basic block given local registers compiler optimizes access within block much simpler task edge systems bear strong resemblance dataflow languages 1960s–1970s 1990s dataflow computers execute programs according dataflow firing rule stipulates instruction may execute time operands available due isolation data similar edge dataflow languages inherently parallel interest followed general interest massive parallelism solution general computing problems studies based existing cpu technology time demonstrated would difficult dataflow machine keep enough data near cpu widely parallel precisely bottleneck modern fabrication techniques solve placing hundreds cpu memory single die another reason dataflow systems never became popular compilers era found difficult work common imperative languages like c++ instead dataflow systems used dedicated languages like prograph limited commercial interest decade compiler research eliminated many problems key difference dataflow edge approaches edge designs intend work commonly used languages edge-based cpu would consist one small block engines local registers realistic designs might hundreds units units interconnected using dedicated inter-block communication links due information encoded block compiler scheduler examine entire block see inputs available send engine execution need examine individual instructions within small increase complexity scheduler examine multiple blocks see outputs one fed inputs another place blocks units reduce inter-unit communications delays modern cpu examines thousand instructions potential parallelism complexity edge allows examine thousand hyperblocks one consisting hundreds instructions gives scheduler considerably better scope additional cost pattern operation gives concept name graph string blocks connected data flowing another advantage edge concept massively scalable low-end design could consist single block engine stub scheduler simply sends blocks called program edge processor intended desktop use would instead include hundreds block engines critically changes designs physical layout chip private information known scheduler program written single-unit machine would run without changes desktop version albeit thousands times faster power scaling likewise dramatically improved simplified block engines turned required linear effect power consumption perhaps greatest advantage edge concept suitable running sort data load unlike modern cpu designs different portions cpu dedicated different sorts data edge cpu would normally consist single type alu-like unit desktop user running several different programs time would get much parallelism scientific user feeding single program using floating point cases scheduler would simply load every block could units low level performance individual block engines would match dedicated fpu instance would attempt overwhelm advantage massive parallelism university texas austin developing edge isa known trips order simplify microarchitecture cpu designed run trips isa imposes several well-defined constraints trips hyperblock trips compiler statically bundles instructions hyperblocks also statically compiles blocks run particular alus means trips programs dependency precise implementation compiled 2003 produced sample trips prototype sixteen block engines 4 4 grid along megabyte local cache transfer memory single chip version trips fabbed ibm canada using 130 nm process contains two grid engines along shared level-2 cache various support systems four chips gigabyte ram placed together daughter-card experimentation trips team set ultimate goal producing single-chip implementation capable running sustained performance 1 tflops 50 times performance high-end commodity cpus available 2008 dual-core xeon 5160 provides 17 gflops cmu cash compiler produces intermediate code called pegasus cash trips similar concept cash targeted produce output specific architecture therefore hard limits block layout university washington wavescalar architecture substantially similar edge statically place instructions within waves instead special instructions phi rho mark boundaries waves allow scheduling
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Computer architecture
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stormcrawler stormcrawler open-source collection resources building low-latency scalable web crawlers apache storm provided apache license written mostly java programming language stormcrawler modular consists core module provides basic building blocks web crawler fetching parsing url filtering apart core components project also provide external resources like instance spout bolts elasticsearch apache solr parserbolt uses apache tika parse various document formats project used production various companies linux.com published q october 2016 author stormcrawler infoq ran one december 2016 comparative benchmark apache nutch published january 2017 dzone.com several research papers mentioned use stormcrawler 2018 particular project wiki contains list videos slides available online stormcrawler used notably common_crawl generating large publicly available dataset news
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Web technology
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usbkill usbkill anti-forensic software distributed via github written python bsd linux os x operating systems designed serve kill switch computer installed fall control individuals entities owner operator wish free software available gnu general public license program developer goes online name hephaest0s created response circumstances arrest silk road founder ross ulbricht u.s. federal agents able get access incriminating evidence laptop without needing cooperation copying data flash drive distracting maintains whitelist devices allowed connect computer usb ports device whitelist connects take actions ranging merely returning lock screen encrypting hard drive even deleting data however also used part computer security regimen prevent surreptitious installment malware spyware clandestine duplication files according creator law enforcement agencies began making computer crime arrests 1990s would often ask judges knock search warrants order deny targets time delete incriminating evidence computers storage media extreme circumstances likely targets could get advance notice arriving police judges would grant power-off warrants allowing utilities turn electricity location raid shortly beforehand forestalling efforts destroy evidence could seized methods effective criminals produced distributed pirated software movies primary large-scale computer crime era 2010s circumstances computer crime changed along legitimate computer use criminals likely use internet facilitate crimes needed remain online time still keep activities discreet used computer security features like lock screens password protection reasons law enforcement attempts apprehend suspected cybercriminals computers use accounts computer online open logged thus easily searchable succeed seizing computer condition methods available bypass password protection may take time police available may legally possible compel suspect relinquish password—in united states many computer-crime investigations take place courts distinguished forcing suspect use material means protecting data thumbprint retinal scan key opposed password passcode purely product suspect mental processes thus protected compelled disclosure fifth amendment usual technique authorities either public entities law enforcement private organizations like companies seizing computer usually laptop believe used improperly first physically separate suspect user computer enough touch prevent closing lid unplugging typing command done often install device usb port spoofs minor actions mouse touchpad keyboard preventing computer going sleep mode would usually return lock screen would require password one program commonly used purpose mouse jiggler agents u.s. federal bureau investigation fbi investigating ross ulbricht founder online black market silk road learned often ran site laptop using wireless networks available branches san francisco public library enough evidence arrest planned catch act running silk road computer logged needed make sure able trigger encryption delete evidence october 2013 male female agent pretended lovers quarrel near working glen park branch according business insider ulbricht distracted got see problem whereupon female agent grabbed laptop male agent restrained ulbricht female agent able insert flash drive one laptop usb ports software copied key files according joshuah bearman wired third agent grabbed laptop ulbricht distracted apparent lovers fight handed agent tom kiernan response circumstances ulbricht arrest programmer known hephaest0s developed usbkill code python uploaded github 2014 available free software gnu general public license currently runs linux os x program installed prompts user create whitelist devices allowed connect computer via usb ports checks default sample rate rate adjusted user may also choose actions computer take detects usb device whitelist default shuts erases data ram swap file users need logged root hephaest0s cautions users must using least partial disk encryption along usbkill fully prevent attackers gaining access gizmodo suggests using virtual machine present computer reboots also used reverse whitelisted flash drive usb port attached user wrist via lanyard serving key instance flash drive forcibly removed program initiate desired routines designed one thing wrote aaron grothe short article usbkill pretty well precaution suggests users rename something innocuous loaded computers case someone might looking seized computer order disable addition designed purpose hephaest0s suggests uses possibly connected user desire frustrate police prosecutors part general security regimen could used prevent surreptitious installation malware spyware copying files protected computer also recommended general use part robust security practice even threats feared 2600 article grothe shared patch also included feature devised allowing program shut network non-whitelisted usb inserted terminal nate brune another programmer created silk guardian version usbkill takes form loadable kernel module since felt could implemented better already issue 2600 following grothe article another writer going name jack d. ripper explained ninja os operating system designed live flash drives handles issue uses bash script resident memory cycles loop boot device i.e. flash drive three times second see still mounted reboots computer
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Computer security
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octopussy software octopussy also known 8pussy free open-source computer-software monitors systems constantly analyzing syslog data generate transmit central octopussy server thus often called siem solution therefore software like octopussy plays important role maintaining within iso/iec 27001-compliant environments octopussy ability monitor device supports syslog protocol servers routers switches firewalls load balancers important applications services main purpose software alert administrators users different kinds events like system outages attacks systems errors applications however unlike nagios icinga octopussy state-checker therefore problems resolved within application software also makes prescription whatsoever messages must be/must analyzed octopussy seen less powerful popular commercial software category event monitoring log analysis octopussy compatible lot linux system distributions like debian ubuntu opensuse centos rhel even meta-distributions gentoo arch linux although octopussy originally designed run linux could ported unix variants like freebsd minimal effort octopussy extensive report generating features also various interfaces software like e.g nsca nagios jabber/xmpp zabbix help software like snare even windows eventlogs processed octopussy licensed terms gnu general public license although octopussy free open-source software variety characteristics also found professional enterprise applications like splunk sawmill kiwi syslog time writing octopussy comes following set features meta- services supported by/known octopussy apache 2 bind bsd kernel bsd pam bsd system cisco routers asr cisco switches clamav denyall reverse proxy drbd f5 bigip fortinet fw hp-tools ironport mailserver juniper netscreen fw juniper netscreen nsm ldap linux apparmor linux auditd linux iptables linux kernel linux pam linux system monit mysql nagios neoteris/juniper fw netapp netcache postfix postgresql samba samhain snmpd squid sshd syslog-ng tacacs vmware esx windows snare agent windows system xen ... events receivable services thus processible octopussy include software requires rsyslog installed syslog-server expects systems monitored run one numerous available syslog services like e.g syslogd/klogd rsyslog syslog-ng software depends apache 2 http server installed apache :asp mod_perl mod_ssl octopussy also requires mysql dbms actual database installed/copied octopussy setup well recent perl interpreter installed operating system variety perl modules cpan e.g crypt :passwdmd5 dbd :mysql json unix :syslog xml :simple comprehensive list modules found within software packages/archives readme.txt file addition nscd rrdtool requirement rrdtool aids creation graphs displayed octopussy dashboard shown per-device/per-service level octopussy receives syslog messages via syslog protocol therefore behaves passively running type network agent remote machines monitoring/surveillance octopussy completely conforms rfc 3164 rfc 3195 ietf describing syslog logging mechanism unix-like/bsd operating systems especially includes internal representation facility severity-principle applicable software driven semi-stateful event correlation engine means engine records thus knows internal state uses extent link together logically related elements device order draw conclusion i.e generate alert octopussy semi-stateful correlation engine called sliding window shifting window logical boundary number events certain period time capable comparing known past events present ones based limited number comparative values octo-dispatcher component used octopussy software receive syslog lines rsyslog dispatch device directories every device registered activated within octopussy gets syslog messages assigned depending device name noteworthy also adjacent octo-replay component program used octopussy software replay log messages device service receives processes recognized logs puts back incoming directory octo-parser octo-uparser two octopussy important core components octo-parser program used octopussy software parse logs syslog format device registered within octopussy basically uses regex-engine commences pattern matching incoming syslog messages octo-uparser restarted every time device services changed check previously received unknown log messages associated service cases octo-pusher also called advance process non-syslog messages incoming devices regard device setting asynchronous helpful process log messages sent octopussy server using e.g ftp rsync ssh/scp octopussy interface gui default user-interface provides configuration management device service management well alert definition therefore extends octopussy core components devices displayed tabular form devices page following descriptors minimum hostname ip address log type device model/type fqdn os hence interface octo-web mainly provides access octopussy core components like octo-commander octo-message-finder octo-reporter octo-statistic-reporter octopussy front-end/gui written perl 5 employing apache :asp structure display content addition octopussy core services also accessed operating system shell represents convenient way administrators start/stop services make fundamental configuration changes octopussy rrd graph generator core component software installed default since generation graphs resource intensive administrators may opt disable octopussy syslog server less powerful cpu low amount ram generated rrd graphs displays activity active services monitored devices highly depending specific service restart octopussy software operation octo-dispatcher octo-parser always process syslog messages buffer queue first rrd graph generation delayed octo-rrd depends octo-scheduler execute octopussy :report function order generate syslog activity rrd graphs scheduled previously finally octo-sender capability send report data arbitrary recipients plug-in/module system octopussy mainly geared towards modification octopussy reports plug-in consists description file defines plug-in name functions code file perl code process actual data also extensions software related octopussy like e.g nagios plug-in checks octopussy core services i.e octo-dispatcher octo-scheduler etc well octopussy parser states log partitions creation new services service patterns presents important way extend octopussy without making changes source code however since patterns outlined simplified regular expressions administrators least basic knowledge regex general strongly recommended build already existing services also understand meaning message objects basic fields message id pattern log level taxonomy table rank usually logs wizard used search system unrecognized syslog messages per device generate new service patterns process creation patterns way enables octopussy distinguish messages based severity taxonomy
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Computer security
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ambient authority ambient authority term used study access control systems subject computer program said using ambient authority needs specify names involved object operation performed order permitted action succeed definition authority ambient sense exists broadly visible environment often necessarily global environment subject request name example suppose c program opens file read access executing call desired file designated name filesystem include authorising information program exercising ambient authority ambient authority requested permissions granted denied based one global properties executing program identity role cases management access control handled separately explicit communication executing program process means access control lists associated objects role-based access control mechanisms executing program means reify permissions granted specific purpose first-class values program able access object acting behalf acting behalf one clients behalf one client another way express intention inevitably leads programs subject confused deputy problem term ambient authority used primarily contrast capability-based security including object-capability models executing programs receive permissions might receive data communicated first-class object references allows determine permissions came thus avoid confused deputy problem however since additional requirements system considered capability system besides avoiding ambient authority non-ambient authority system synonym capability system ambient authority dominant form access control computer systems today user model access control used unix windows systems ambient authority model programs execute authorities user started means executing programs inevitably given permissions need task unable determine source number types permission program executing ambient authority access control model little option designate permissions try exercise hoping best property requires excess permissions granted users roles order programs execute without error
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Computer security
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state logic state logic control system programming method created plcs state logic control system uses state transition diagram model reality thus using fundamentals finite-state machine theory basis programming language state logic enables users model application trying control using hierarchy consists tasks subdivided states described statements 'tasks description sequential activity model machines applications processes modelled state logic usually contain one 'task representing several different possibly parallel activities activities contain given number 'states finite-state machine theory one 'state active time certain inputs outputs cause transition different states given plcs usually control systems easily represented state transition diagram use high-level programming language state logic greatly helps plc programmer making intuitive control programs
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Programming language topics
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custom hardware attack cryptography custom hardware attack uses specifically designed application-specific integrated circuits asic decipher encrypted messages mounting cryptographic brute force attack requires large number similar computations typically trying one key checking resulting decryption gives meaningful answer trying next key computers perform calculations rate millions per second thousands computers harnessed together distributed computing network number computations required average grows exponentially size key many problems standard computers fast enough hand many cryptographic algorithms lend fast implementation hardware i.e networks logic circuits also known gates integrated circuits ics constructed gates often execute cryptographic algorithms hundreds times faster general purpose computer ic contain large numbers gates hundreds millions 2005 thus decryption circuit cell replicated thousands times one ic communications requirements ics simple must initially loaded starting point key space situations comparison test value see known plaintext attack output consists signal ic found answer successful key since ics lend mass production thousands even millions ics applied single problem ics mounted printed circuit boards standard board design used different problems since communication requirements chips wafer-scale integration another possibility primary limitations method cost chip design ic fabrication floor space electric power thermal dissipation alternative approach use fpgas field-programmable gate arrays slower expensive per gate reprogrammed different problems copacobana cost-optimized parallel code breaker one machine consisting 120 fpgas type xilinx spartan3-1000 run parallel earliest custom hardware attack may bombe used recover enigma machine keys world war ii 1998 custom hardware attack mounted data encryption standard cipher electronic frontier foundation deep crack machine cost u.s. 250,000 build decrypted des challenge ii-2 test message 56 hours work confirmed des cracker copacobana machine cost-optimized parallel code breaker built 2006 unlike deep crack copacobana consist commercially available reconfigurable integrated circuits copacobana costs 10,000 build recover des key 6.4 days average cost decrease roughly factor 25 eff machine impressive example continuous improvement digital hardware adjusting inflation 8 years yields even higher improvement 30x since 2007 sciengines gmbh spin-off company two project partners copacobana enhanced developed successors copacobana 2008 copacobana rivyera reduced time break des current record less one day using 128 spartan-3 5000 generally believed large government code breaking organizations u.s. national security agency make extensive use custom hardware attacks examples declassified
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Computer security
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richard thomas solicitor richard james thomas best known tenure information commissioner united kingdom post held december 2002 june 2009 time office raised concerns increased use closed-circuit television cctv introduction id cards uk thomas currently deputy chairman co-opted council member consumers association trustee director whitehall industry group chairman administrative justice tribunals council 1 september 2009 abolition august 2013 also visiting professor law northumbria university born june 1949 son magistrate thomas attended public school studied law southampton university late 1960s later awarded honorary doctor laws university early career worked articled clerk solicitor freshfields bruckhaus deringer 1971 citizens advice bureau notting hill 1974 went work legal public affairs positions national consumer council 1979 office fair trading national consumer council also involved campaign freedom information secondary involvement publishing book essays entitled consuming secrets appointment information commissioner first director public policy clifford chance married julia clarke since 1974 three adult children wife live reigate surrey thomas appointed commander order british empire cbe 2009 birthday honours public service document submitted leveson inquiry witness alec owens indicates richard thomas refused prosecute perpetrators phone hacking despite receiving recommendation parties identified involved jointly prosecuted 'conspiracy breach data protection act 1998
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Computer security
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julia hirschberg julia hirschberg american computer scientist noted research computational linguistics natural language processing currently percy k. vida l. w. hudson professor computer science columbia university hirschberg received first ph.d degree history 16th-century mexico university michigan 1976 served history faculty smith college 1974 1982 subsequently shifted computer science studies receiving m.s computer information science university pennsylvania 1982 ph.d computer information science university pennsylvania 1985 upon graduation university pennsylvania 1985 hirschberg joined bell labs member technical staff linguistics research department worked improving prosody assignment text-to-speech synthesis tts bell labs tts system promoted department head 1994 created new human computer interface research lab department remained bell labs 1996 moved labs research part corporate reorganization 2002 joined columbia university faculty professor department computer science served chair computer science department 2012-2018 hirschberg research included prosody discourse structure spoken dialogue systems speech search recently analysis deceptive speech hirschberg among first combine natural language processing nlp approaches discourse dialogue speech research pioneered techniques text analysis prosody assignment text-to-speech synthesis bell laboratories 1980s 1990s developing corpus-based statistical models based upon syntactic discourse information general use today tts systems janet pierrehumbert developed theoretical model intonational meaning leader development tobi conventions intonational description extended numerous languages today widely used standard intonational annotation hirschberg pioneer together gregory ward much experimental work intonational sources language meaning interact pragmatic phenomena particularly meaning accent intonational prominent items meaning intonational contours also innovated numerous areas involving prosody meaning including role grammatical function surface position pitch accent location use prosody disambiguating cue phrases discourse markers diane litman role prosody disambiguation english italian spanish cinzia avesani pilar prieto automatic identification speech recognition errors using prosodic information labs worked fernando pereira steve whittaker others speech search developing new interfaces speech navigation columbia students continued extended research spoken dialogue systems automatically detecting speech recognition errors inappropriate system queries modeling turn-taking behavior dialogue entrainment modeling generating clarification dialogues automatic classification trust charisma deception emotion speech speech summarization prosody translation hedging behavior text speech text-to-speech synthesis speech search low resource languages also holds several patents tts speech search corpora collaborators collected include boston directions corpus columbia sri colorado deception corpus columbia games corpus served numerous technical boards editorial committees computing research association cra board directors serves co-chair cra-w. also noted leadership broadening participation computing served member cra committee status women computing research cra-w since 2010 hirschberg notable awards include
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Computational linguistics
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astra linux astra linux russian linux-based computer operating system developed meet needs russian army armed forces intelligence agencies provides data protection level top secret russian classified information grade officially certified russian defense ministry federal service technical export control federal security service creator os scientific/manufacturing enterprise rusbitech applying solutions according russian government decree №2299-р 17/10/2010 orders federal authorities budget institutions implement free software usage os releases named hero cities russia cis one release general purpose code named oryol aimed achieving small mid-business goals releases marked special purpose — smolensk x86-64 pcs tula networking hardware novorossiysk arm mobile devices murmansk ibm system z mainframes rusbitech also manufactures soft/hardware trusted boot control module maksim-m1 м643м1 pci bus prevents unauthorized access offers raised digital security features module besides astra linux also supports oses linux kernel 2.6.x 5.x.x well several microsoft windows oses declared astra linux licenses correspond russian international laws n't contradict spirit demands gpl license system uses .deb packages astra linux considered recognized debian derivative rusbitech partnership relations linux foundation document foundation special edition version paid used many russian state-related organizations particularly used russian national center defence control talks deploy mass usage astra linux numerous state institutions republic crimea — legitimate usage popular oses questionable international sanctions ukrainian crisis also plans cooperation rusbitech huawei january 2018 announced astra linux going deployed russian army computers microsoft windows dropped february 2018 rusbitech announced ported astra linux russian-made elbrus microprocessors february 2019 astra linux announced implemented tianwan nuclear power plant china september 2019 commercial sales smartphones tablets astra linux expected start
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Computer architecture
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arkos arkos linux distribution based arch linux designed primarily hosting web sites services cheap arm-based devices raspberry pi cubieboard 2 cubietruck beaglebone black plans expand platforms x86 jacob cook arkos primary developer originally conceived idea arkos realizing extensive amount time required set self-hosted services explained saying good deal experience linux system administration still took huge amount time research get services wanted set secured properly cook aims reduce dependence cloud services make data collection harder march 2014 arkos developing stages creator arkos also set citizenweb organization responsible development operating system citizenweb also solicited money successful crowdsourcing campaign finish platform april 2017 arkos discontinued lack resources principal reason source code remains available github
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Operating systems
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cellebrite cellebrite mobile synchronization israeli company manufactures data extraction transfer analysis devices cellular phones mobile devices company subsidiary japan sun corporation cellebrite headquartered petah tikva israel two subsidiary companies cellebrite usa corp. cellebrite gmbh respectively based parsippany new jersey us munich germany cellebrite fully owned subsidiary sun corporation publicly traded company listed jasdaq 6736/jq based nagoya japan 2017 cellebrite mobile lifecycle division rebranded mobilogy mobilogy produces hardware software phone-to-phone data transfer backup mobile applications electronic software distribution data analysis tools mobilogy products used various mobile operators deployed wireless retail points sale mobilogy works handset manufacturers ensure compatibility devices released public cellebrite mobile forensics division established 2007 produces software hardware mobile forensics purposes used federal state local law enforcement intelligence agencies military branches corporate security investigations law firms private digital forensic examiners cellebrite established israel 1999 avi yablonka yaron baratz yuval aflalo ron serber joined cellebrite dec 2000 vp r yossi carmil aug.2004 ceo later ron yossi share ceo title co-ceo cellebrite first manufactured hardware software offered compressive phone-to-phone data transfer devices offered contact synchronization content transfer tools mobile phones intended use wireless carrier sales support staff retail stores initially cellebrite commercial products used tool migration is-95 cdma enabled mobile phones gsm standard later cellebrite wireless carriers retailers universal memory exchanger ume gained additional data extraction transfer capabilities well additional mobile phone diagnostics backup application management delivery 2007 cellebrite established independent division targeted mobile forensics industry cellebrite mobile forensics introduced mobile forensics products 2007 family brand name 'universal forensic extraction device ufed ability extract physical logical data mobile devices cellular phones hand-held mobile devices including ability recover deleted data decipher encrypted password protected information also 2007 cellebrite acquired futuredial incorporated one major shareholders sun corporation japan today fully owned subsidiary sun corporation april 2011 michigan chapter american civil liberties union questioned whether michigan state police msp troopers using cellebrite ufeds conduct unlawful searches citizens cell phones following refusal grant mclu 2008 freedom information act request unless organization paid 544,000 retrieve reports msp issued statement claiming honored fourth amendment searching mobile devices march 2016 reported cellebrite offered unlock iphone involved fbi–apple encryption dispute later fbi announced successfully accessed iphone thanks third party press report claimed cellebrite assisted unlocking device fbi source denied 2017 data dump suggests cellebrite sold data extraction products turkey united arab emirates russia mobile retail industry cellebrite provides gadgets phone-to-phone content management transfer used primarily stand-alone device point sale electronic software distribution content backup management used primarily over-the-air programming cellebrite universal memory exchanger ume standalone phone-to-phone memory transfer backup machine transfers content including pictures videos ringtones sms phone book contact data cellebrite ume touch predecessor ume-36 intermediate information range mobile phones smartphones pdas support mobile operating systems including symbian windows mobile palm blackberry ios android cellebrite ume standalone device acts universal data channel two mobile devices extracts reads parses data source mobile device transfers on-the-fly target device without storing data ume device ume automatically determine types phones connected re-structure data fly according source target phone storage formats data fields addition apploader device analytics tools may 2012 cellebrite introduced several new retail products services including pos diagnostics tool cell phone buy-back program integration ume touch self-service point 2007 cellebrite announced line products called 'universal forensic extraction device ufed aimed digital forensics investigation industry ufed system hand-held device optional desktop software data cables adapters peripherals ufed additionally integrated subscriber identity module sim reader unlike commercial counterpart ume ufed system sold approved government corporate organizations also unlike ume ufed extracts mobile device data directly onto sd card usb flash drive another major difference ume ufed ability break codes decipher encrypted information acquire hidden deleted data ufed named phone forensic hardware tool year four years running forensic 4cast awards cellebrite claims ufed ability extract data nearly 8,200 devices june 2012 include smartphones pda devices cell phones gps devices tablet computers ufed extract decrypt parse analyze phonebook contacts types multimedia content sms mms messages call logs electronic serial numbers esn international mobile equipment identity imei sim location information non-volatile memory volatile storage alike ufed supports cellular protocols including cdma gsm iden tdma also interface different operating systems file systems ios android os blackberry symbian windows mobile palm well legacy feature cell phones operating systems ufed enables retrieval subject data via logical see get file system e.g. directories files physical extractions i.e hex dump bit-for-bit copy mobile device entire storage physical extraction enables recover deleted information decipher encrypted data acquire information password-protected mobile applications facebook skype whatsapp browser-saved passwords ufed physical extraction functionality also overcome devices password locks well sim pin numbers cellebrite claims first mobile forensics industry achieved number smartphone forensic breakthroughs include physical extraction decoding blackberry flash memory going beyond mass storage ipd backups android user/pattern lock bypass physical extraction decoding physical extraction phones chinese chipsets including mediatek spreadtrum tomtom gps trip-log decryption decoding ios device unlocking research development cellebrite claims maintain integrity digital evidence 12 january 2017 reported unknown hacker acquired 900 gb worth confidential data cellebrite external servers data dump includes alleged usernames passwords logging cellebrite databases connected company my.cellebrite domain also contains appear evidence files seized mobile phones logs cellebrite devices data suggests cellebrite sold data extraction products countries turkey united arab emirates russia
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Computer security
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fourth-generation programming language fourth-generation programming language 4gl computer programming language belongs class languages envisioned advancement upon third-generation programming languages 3gl programming language generations aims provide higher level abstraction internal computer hardware details making language programmer-friendly powerful versatile definition 4gl changed time typified operating large collections information rather focusing bits bytes languages claimed 4gl may include support database management report generation mathematical optimization gui development web development researchers state 4gls subset domain-specific languages concept 4gl developed 1970s 1990s overlapping development 3gl 3gls like c c++ c java javascript remain popular wide variety uses 4gls originally defined found narrower uses advanced 3gls like python ruby perl combine 4gl abilities within general-purpose 3gl environment also libraries 4gl-like features developed add-ons popular 3gls blurred distinction 4gl 3gl 1980s 1990s efforts develop fifth-generation programming languages 5gl though used earlier papers discussions term 4gl first used formally james martin 1981 book applications development without programmers refer non-procedural high-level specification languages primitive way early 4gls included informatics mark-iv 1967 product sperry mapper 1969 internal use 1979 release motivations '4gl inception continued interest several term apply large set software products also apply approach looks greater semantic properties implementation power 3gl offered greater power programmer 4gl open development environment wider population early input scheme 4gl supported entry data within 72-character limit punched card 8 bytes used sequencing card tag would identify type function judicious use cards 4gl deck could offer wide variety processing reporting capability whereas equivalent functionality coded 3gl could subsume perhaps whole box cards 72-character metaphor continued hardware progressed larger memory terminal interfaces even limitations approach supported highly sophisticated applications interfaces improved allowed longer statement lengths grammar-driven input handling greater power ensued example described nomad page development 4gl influenced several factors hardware operating system constraints large weight 4gl first introduced disparate mix hardware operating systems mandated custom application development support specific system order ensure sales one example mapper system developed sperry though roots back beginning system proven successful many applications ported modern platforms latest variant embedded bis offering unisys mark-iv known vision builder offered computer associates santa fe railroad used mapper develop system project early example 4gl rapid prototyping programming users idea easier teach railroad experts use mapper teach programmers intricacies railroad operations one early portable languages 4gl properties ramis developed gerald c. cohen mathematica mathematical software company cohen left mathematica founded information builders create similar reporting-oriented 4gl called focus later 4gl types tied database system far different earlier types use techniques resources resulted general improvement computing time interesting twist 4gl scene realization graphical interfaces related reasoning done user form 'language poorly understood number different types 4gls exist 4gls integrated tools allow easy specification required information twenty-first century 4gl systems emerged low code environments platforms problem rapid application development short periods time vendors often provide sample systems crm contract management bug tracking development occur little programming extract data files database create reports wide range formats done report generator tools
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Programming language topics
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chase h.q game well received gaming industry resulting three arcade-based sequels released special criminal investigation 1989 1992 chase h.q 2 2007 two spin-offs also released crime city 1989 quiz h.q 1990 game ported many home computers ocean software 1989 including versions zx spectrum amstrad cpc commodore 64 msx amiga atari st. taito produced versions family computer 1989 game boy 1990 master system 1990 turbografx-16 1990 game gear 1991 saturn 1996 released playstation 2 japan 2007 part taito memories ii volume 2 start level player informed pursuing great distance away must apprehend criminal time limit expires criminal car constantly moving away player repeatedly crashes drives slowly criminal escape points game road splits correct turn must taken otherwise take longer catch criminal vehicle reached time limit extended vehicle must rammed number times criminal forced stop arrested game includes five levels initial time limit reach criminal time extension ram criminal 60 65 70 seconds nancy chase hq start every level calls radio frequency always 144.x various mhz actually 2-meter band amateur ham radio frequencies although superficially similar technology sega run chase hq features significant technical advancements title presentation perspective hills track splits villains arcade versions last villain car always listed unidentified ocean released versions game zx spectrum amstrad cpc commodore 64 commodore amiga atari st december 1989 msx version released february 1990 spain roughly one month later launch rest ocean versions market taito produced ports known taito chase h.q family computer 1989 game boy 1990/1991 master system 1990 turbografx-16 1990 game gear 1991 released genesis chase h.q ii known super h.q japan minor changes including alternative player vehicles december 1990 game included wheels fire compilation also featured hard drivin power drift turbo outrun june 1991 game released power compilation also featured altered beast turrican rainbow islands x-out 1993 taito released super chase h.q known japan super h.q criminal chaser super nes unlike home versions played first person perspective based upon super chase criminal termination rather original chase h.q gameplay modeled original aspects s.c.i incorporated also super chase h.q game boy released exclusively north america 1994 game similar game boy taito chase h.q 1991 1996 taito released emulation arcade original sega saturn japan bundled together special criminal investigation one disc 2000 chase h.q secret police released game boy color july 2008 turbografx-16 version game re-released wii virtual console spin-off released 1989 titled crime city game play deviates traditional third-person driving instead side scrolling type shooter game well received critics upon release arcades computer video games gave positive review stating last racing game something whizzing around track beat course time concluded fast challenging great graphics good clear sound effects definitely winner ace said run theme keeps expanded presented different ways like power drift chase hq best far concluded game driving violence winning coin-up combination crash said great game ultimate arcade version cops-and-robbers movies according arcade history arguably first sprite-scaled racer since run truly capture gaming public imagination home computer conversions also mostly well received critics 16-bit amiga atari st versions received positive reviews 8-bit zx spectrum amstrad cpc conversions received high review scores generally recognised accurate playable ocean software home computer releases three zx spectrum magazines awarded 94 praising speed game originality crash gave game 95 sinclair user awarded 96 hand 8-bit commodore 64 conversion received generally negative reception japan 1989 arcade version nominated hit game year voted 10th place according ocean software advert 1989 arcade version voted arcade game year 1989/1990 golden joystick awards 8-bit home computer versions awarded best 8-bit coin-op conversion best 8-bit soundtrack spectrum version also topped computer video games best games '89 list along super mario bros. 2 zx spectrum version game went number 2 uk sales charts behind rainbow islands spectrum version voted number 1 sinclair poll readers top 100 games time 1993 brian kuh weirs beach new hampshire holds official arcade world record score 3,596,680 points achieved 1 june 2006 funspot family fun center weirs beach new hampshire robert gray dumfriesshire scotland holds official mame world record score 11,490,280 points achieved 13 june 2010 chase h.q successful enough earn two arcade-based sequels widely released special criminal investigation released 1989 extremely rare super chase criminal termination released 1992 also earned two spin-offs run gun crime city quiz game quiz h.q. special criminal investigation expands original addition guns passenger rise t-top nissan 300zx z32 shoot oncoming targets take advantage enemies placed throughout level attempt shoot ram player attempt pursue main criminal deviating relatively realistic tracks offer original sequel features pursuits waterfalls unfinished sections elevated highway. third arcade release chase h.q series released 1992 1997 playstation game ray tracers developed released taito described less follow game differences different speed-boost system greater variety targets february 2006 chase h.q nancy yori kinkyuu renraku presented arcade operator union trade show tokyo game released chase h.q 2 later year saint etienne recorded demo dance track called chase hq inspired chase h.q includes samples oh man punch pedal exclamations game action track released bonus track 2009 deluxe reissue band 1991 album foxbase alpha chase hq gameplay involved ramming enemy car avoiding oncoming traffic cited precursor gameplay later titles driver burnout
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Computer architecture
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google cloud dataflow google cloud dataflow fully managed service executing apache beam pipelines within google cloud platform ecosystem google cloud dataflow announced june 2014 released general public open beta april 2015 january 2016 google donated underlying sdk implementation local runner set ios data connectors access google cloud platform data services apache software foundation donated code formed original basis beam project
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Distributed computing architecture
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json patch json patch web standard format describing changes json document meant used together http patch allows modification existing http resources json patch media type codice_1 json patch document structured json array objects object contains one six json patch operations add remove replace move copy test structure influenced specification xml patch syntax looks like every object two mandatory members op path one operation per object though many objects/operations every array operations performed order first operation array goes first second operation acts upon result previous operation json patch documents atomic one operation document fails operation carried operations following add adds value object array remove removes value object array replace replaces value logically identical using remove add copy copies value one path another adding value specified location another location move moves value one place another removing one location adding another test tests equality certain path certain value
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Programming language topics
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philips 68070 scc68070 philips semiconductors-branded motorola 68000-based 16/32-bit processor produced license marketed externally high-performance microcontroller almost exclusively used combined philips scc66470 vsc video- systems controller philips cd-i interactive entertainment product line additions motorola 68000 core include differences motorola 68000 core include scc68070 mostly binary compatible motorola 68000 equivalent chip motorola 680x0 series particular scc68070 follow-on motorola 68060 even though scc68070 32-bit processor internally 24-bit address bus giving theoretical 16mb maximum ram however possible on-board peripherals mapped internally
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Computer architecture
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3do blaster 3do blaster add-on produced creative labs designed allow compatible windows-based pcs play games 3do interactive multiplayer full-sized isa compatibility card unlike add-ons emulate 3do system rather whole system logic board included input controllers output video audio redirected pc product marketed single board cd-rom drive owners drives panasonic interface bundled necessary cd-rom drive software drivers allowed dos windows 3.1 based gameplay although windows based gaming featured real-time stretching game window screenshot capturing graphics boards time 1994 par system needs pass-through using vga feature connector link used thus reserving area screen used 3do blaster card output windows environment – running dos full-screen option thus impact cpu first 3do system panasonic real fz-1 fmv daughter-card enabling video cd playback planned since 3do blaster failed achieve momentum never released saved games stored nvram card supposedly using resources pc prevent hacking card sold cables needed 3do controller logitech two 3do games cd shock wave electronic arts gridders tetragon despite showing 'long boxes two games back packing box included jewel cases third cd containing demos popular 3do games also included included software aldus aldus photostyler se aldus gallery effects vol 1 pictures titles seen back 3do blaster packing box
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Computer architecture
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blink browser engine blink browser engine used google chrome browser many projects developed part chromium project contributions google facebook microsoft opera software asa adobe systems intel ibm samsung others first announced april 2013 blink fork webcore component webkit originally fork khtml kjs libraries kde used chrome starting version 28 opera 15+ vivaldi amazon silk chromium-based browsers frameworks much webcore code used features google chrome implemented differently sandboxing multi-process model parts altered blink fork although made slightly bulkier allowed greater flexibility adding new features future fork also deprecates vendor prefixes existing prefixes phased new experimental functionality instead enabled opt-in basis aside planned changes blink initially remains relatively similar webcore commit count google largest contributor webkit code base since late 2009 blink naming influenced non-standard presentational blink html element introduced netscape navigator supported presto- gecko-based browsers august 2013 blink contrary name never functionally supported element several projects exist turn chromium blink reusable software framework developers chromium blink implemented six platforms windows mac linux chrome os android android webview ios versions chromium continue use parent renderer webkit webcore
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Web technology
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rebecca bace rebecca becky gurley bace 1955–2017 american computer security expert pioneer intrusion detection spent 12 years us national security agency created computer misuse anomaly detection cmad research program known den mother computer security also influential early stages intelligence community venture capital major player silicon valley investments cyber security technology bace grew rural alabama one seven children diagnosed epilepsy adolescence mother war bride japan following world war ii father self-educated teamster alabama due prevailing attitudes illness women neurologist suggested stay home collect disability following high school credited local librarian family friend bertha nel allen encouragement apply college scholarships scholarships charitable foundations set betty crocker jimmy hoffa senior year high school 1973 accepted university alabama birmingham woman engineering financial hardship frequent employment interruptions took eight years classes various schools earn degree bace first became interested computing freshman year working punch cards programming fortran cobol ibm mainframe got first engineering job teaching engineering lab approached couple xerox technicians needed fill affirmative action requirements accepted job specialist repairing copier machines experience stated faced significant gender racial bias sometimes customers would raise ruckus deal believed given second best showed even though better educated men graduation 1984 bace started working nsa searching flexible job allow care autistic son later diagnosed leukemia took assignment 1989 national computer security center ncsc chartered part nsa expressly deal computer security issues department defense intelligence community bace served program manager intrusion detection research specifically transferring research relatively new commercial security products market played pivotal role apprehension kevin mitnick proving trace back capture possible beyond theoretical context also provided seed funding computer security labs uc davis purdue university following death son bace went serve deputy security officer los alamos national laboratory computing information communications division left los alamos 1998 started infidel inc. security consulting company 2002 signed venture capital consultant trident capital silicon valley bace also briefly served technical vp cyber security practice in-q-tel investment arm us intelligence community death served chief strategist center forensics information technology security cfits university south alabama venture capitalist provided expert advice generation security startups including qualys sygate irobot arxan technologies hytrust neohapsis
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Computer security
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roller coaster database roller coaster database rcdb roller coaster amusement park database begun 1996 duane marden grown feature statistics photos 5000 roller coasters around world publications mentioned rcdb include new york times los angeles times toledo blade orlando sentinel time forbes mail guardian chicago sun-times rcdb started 1996 duane marden computer programmer brookfield wisconsin website run web servers marden basement location st. louis 2019 marden still operates site roller coaster entry includes following information ride current amusement park location type status existing standing operating sbno defunct opening date make/model cost capacity length height drop number inversions speed duration maximum vertical angle trains special notes entries may also feature reader-contributed photos and/or press releases site also categorizes rides special orders including list tallest coasters list fastest coaster list inversions coaster list parks inversions etc. sortable steel wooden roller coaster entry links back page lists park roller coasters past present includes brief history links fan web pages saluting park site available ten languages english german french spanish dutch portuguese italian swedish japanese simplified chinese
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Databases
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list microsoft operating systems following list microsoft written published operating systems codenames microsoft gave operating systems see microsoft codenames another list versions microsoft windows see list microsoft windows versions releases windows windows 2000 part windows nt family
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Operating systems
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diet diet software grid-computing middleware diet sits operating system handles details hardware application software deals specific computational task hand diet created 2000 designed high-performance computing currently developed inria école normale supérieure de lyon cnrs claude bernard university lyon 1 sysfera open-source software released cecill license like netsolve/gridsolve ninf diet compliant gridrpc standard open grid forum aim diet project develop set tools build computational servers distributed resources managed transparent way middleware work workstations clusters grids clouds diet used manage décrypthon grid installed ibm six french universities bordeaux 1 lille 1 paris 6 ens lyon crihan rouen orsay usually gridrpc environments five different components clients submit problems servers servers solve problems sent clients database contains information software hardware resources scheduler chooses appropriate server depending problem sent information contained database monitors get information status computational resources diet architecture follows different design composed two approaches developed workflow management diet uses additional entity called dag entity work two modes one defines complete scheduling workflow ordering mapping one defines ordering workflow execution mapping done next step client using master agent find server workflow services run diet provides degree control scheduling subsystem via plug-in schedulers service request application arrives sed sed creates performance-estimation vector collection performance-estimation values pertinent scheduling process application values stored structure either values provided cori collectors resource information custom values generated sed design estimation vector subsystem modular cori generates basic set performance-estimation values stored estimation vector identified system-defined tags information number cores total memory number bogomips hard drive speed etc. static well dynamic information like predicted time solve problem given resource average cpu load thus transferred server daemon scheduler agent order provide pertinent information better scheduling mentioned used correlation application-driven scheduler possibility diet server daemon better understanding application needs request specific scheduling relaying information stored vector three different data managers integrated diet parallel resources generally accessible lrms local resource management system also called batch system diet provides interface several existing lrms execute jobs loadleveler ibm resources openpbs fork well-known pbs system oar batch scheduler used grid'5000 research grid developed imag grenoble submitted jobs parallel jobs coded using mpi standard instantiation mpich lam cloud extension diet created 2009 diet thus able access cloud resources two existing cloud providers
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Distributed computing architecture
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