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vesa plug display vesa plug display p video connector digital monitors flat panel displays video projectors ratified vesa introduced around time dfp marketed replacement vesa enhanced video connector extension dvi unlike dvi never achieved widespread implementation p connector shares pin layout vesa evc pins assigned carrying analogue audio video signals reused carry digital video signals basic p line carries single-link tmds digital video signal max 160 mhz supports vesa display data channel version 2 analogue video signals supported must capable carrying least 150 mhz bandwidth usb version specified supported would intended contemporary usb standards usb connector intended passing mouse movements projector wireless remote computer presentation software firewire supported must compliant ieee 1394-1995 specification although pin layout comes vesa evc connector shell slightly different p d-a/d compatible evc device except missing vesa evc features p d-d addition regular p connector standard also specifies 40-pin microribbon connector defined making digital video connection articles register sometimes mistake p port alternative form apple display connector adc carries higher current different pin layout support firewire
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Computer architecture
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oracle spatial graph oracle spatial graph formerly oracle spatial forms separately-licensed option component oracle database spatial features oracle spatial graph aid users managing geographic location-data native type within oracle database potentially supporting wide range applications — automated mapping facilities management geographic information systems am/fm/gis wireless location services location-enabled e-business graph features oracle spatial graph include oracle network data model ndm graphs used traditional network applications major transportation telcos utilities energy organizations rdf semantic graphs used social networks social interactions linking disparate data sets address requirements research health sciences finance media intelligence communities geospatial feature oracle spatial graph provides sql schema functions facilitate storage retrieval update query collections spatial features oracle database spatial component spatial feature consists geometric representation shape coordinate space — referred geometry oracle spatial geospatial data features consist network data model feature property graph model used model analyze physical logical networks used industries transportation logistics utilities features include rdf semantic graph feature supports world wide web consortium w3c rdf standards provides rdf data management querying inferencing commonly used variety applications ranging semantic data integration social network analysis linked open data applications features include oracle spatial graph option oracle enterprise edition must licensed separately also included oracle database cloud service high performance edition extreme performance edition included oracle standard edition oracle standard edition one however latter two editions allow use subset spatial features called oracle locator extra cost appendix oracle spatial graph developer guide specifies functions allowed locator oracle rdbms first incorporated spatial-data capability modification oracle 4 made scientists working canadian hydrographic service chs joint development team chs oracle personnel subsequently redesigned oracle kernel resulting spatial data option sdo oracle 7 sdo_ prefix continues use within oracle spatial implementations spatial indexing system sdo involved adaptation riemannian hypercube data-structures invoking helical spiral 3-dimensional space allows n-size features also permitted highly efficient compression resulting data suitable petabyte-size data repositories chs major corporate users required also improving search retrieval times helical hyperspatial code hhcode developed chs implemented oracle spatial comprises form space-filling curve oracle 8 oracle corporation marketing dubbed spatial extension simply oracle spatial primary spatial indexing system longer uses hhcode standard r-tree index since july 2012 option named oracle spatial graph highlight graph database capabilities product network data model graph introduced oracle database 10g release 1 rdf semantic graph introduced oracle database 10g release 2 oracle documentation library http //www.oracle.com/pls/db121/portal.portal_db selected=7 frame= see
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Databases
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network crack program hacker group network crack program hacker group ncph group chinese hacker group based zigong sichuan province group first gained notoriety hacking 40 hacker association websites china attacks grew sophistication notoriety 2006 received international media attention early 2007. idefense linked ginwui rootkit developed leader tan dailin wicked rose attacks us department defense may june 2006. idefense linked group many 35 zero-day hacker proof-of-concept codes used attacks period 90 days summer 2006 also known remote-network-control programs offer download wicked rose announced blog post group paid work group sponsor unknown group four core members 2006 wicked rose kungbim charles rodag approximately 10 members total group current membership unknown wicked rose also known meigui 玫瑰 pseudonym chinese hacker tan dailin first noted hacker patriotic attacks 2001 2005 wicked rose contracted sichuan military command communication department instructed participate chengdu military command network attack/defense competition winning local competition received month intense training simulating attacks designing hacking tools drafting network-infiltration strategies team represented sichuan military command competition provinces went win wicked rose also credited development ginwui rootkit used attacks us department defense 2006 group leader responsible managing relationships sponsors paying ncph members work april 2009 arrested committing distributed denial service attacks hackbase hackerxfiles 3800hk possibly purpose committing blackmail organizations attacked collected information attack turned public security department authorities conducted investigation shut website hackbase reported wicked rose arrested faces 7 years prison group expelled hacker wzt 20 may 2006 although cause unknown group ejected soon zero-day attacks publicly disclosed wzt coding expert within group former ncph member associates chinese hacker li0n founder honker union china huc wicked rose credits chinese hacker whg also known fig one developers ginwui rootkit whg expert malicious code security firms researching wicked rose activities connected chinese hacker group evil security team group known remote-network-control programs offer free website exploitation zero-day vulnerabilities microsoft office suite products founding 2004 group earned reputation among hacking groups hacking 40 hacker association websites china wicked rose creator ginwui rootkit code support posts chinese hacker message boards also available ncph blog security researchers discovered rootkit 18 may 2006 attackers utilized attacks us japan attackers introduced us attack department defense entity used two different versions rootkit attacks may june 2006 according f-secure ginwui fully featured backdoor rootkit characteristics distributed word documents backdoor ginwui creates allows controlling hacker control certain processes compromised computer including ability idefense links ncph many 35 zero-day proof-of-concept codes used attacks microsoft office products period 90 days summer 2006 due use malware developed wicked rose available public domain time group graduated early attacks exploiting microsoft word end 2006 also using power point excel attacks ncph utilizes exploits spear phishing attacks blog wicked rose discussed preference spear phishing attacks first collection phase information gathered using open source information employee databases mailboxes company system may also conduct analysis user id allows track understand activities finally conducts attack using information collected someone likely open infected document spear phishing attacks attributed ncph increased sophistication time phishing attacks beginning 2006 targeted large numbers employees one attack attributed group later year targeted one individual us oil company using socially engineered emails infected power point documents winning military network attack/defense competition group obtained sponsor paid 2000 rmb per month idefense believes sponsor likely people liberation army pla definitive evidence support claim 2006 attacks took place sponsor increased pay 5000 rmb group current sponsor unknown time reporter simon elegant interviewed eight members group december 2007 part article chinese government cyber operations us government interview members referred using code names security firm idefense published reports group exploits devoted webinar group capabilities relationships chinese hackers scott henderson chinese linguistics chinese hacker expert also devoted several blog posts group ongoing activities four core members group blogged activities one point another group blog ncph.net also offered network-infiltration programs download scott henderson describes wicked rose early blog posts revealing damning thing ever seen chinese hacker write interview time reporter wicked rose took group blog blog july 2008 group blog returned modified content withered rose also began blogging saying busy time blog new job allows time blog chinese officials removed blogs arrest april 2009 rodag also blogs recent post august 2008 last post ie vulnerabilities attackers used exploit user desktop
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Computer security
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budapest declaration machine readable travel documents budapest declaration machine readable travel documents declaration issued future identity information society fidis network excellence raise concern public risks associated security architecture related management machine readable travel documents mrtds current implementation passports european union creates threats related identity theft privacy declaration proclaimed budapest september 2006
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Computer security
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execution unit computer engineering execution unit also called functional unit part central processing unit cpu performs operations calculations instructed computer program may internal control sequence unit confused cpu main control unit registers internal units arithmetic logic unit alu address generation unit agu floating-point unit fpu load-store unit lsu branch execution unit beu smaller specific components common modern cpus multiple parallel execution units referred superscalar design simplest arrangement use one bus manager manage memory interface others perform calculations additionally modern cpus execution units usually pipelined
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Computer architecture
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open source linux organization hewlett-packard open source linux organization earlier known hp linux group 100 linux programmers 300 products free software released 300 open source printer drivers
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Operating systems
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x87 x87 floating-point-related subset x86 architecture instruction set originated extension 8086 instruction set form optional floating-point coprocessors worked tandem corresponding x86 cpus microchips names ending 87 also known npx numeric processor extension like extensions basic instruction set x87 instructions strictly needed construct working programs provide hardware microcode implementations common numerical tasks allowing tasks performed much faster corresponding machine code routines x87 instruction set includes instructions basic floating-point operations addition subtraction comparison also complex numerical operations computation tangent function inverse example x86 processors since intel 80486 x87 instructions implemented main cpu term sometimes still used refer part instruction set x87 instructions standard pcs compilers programmers use rather slow library calls perform floating-point operations method still common low-cost embedded systems x87 registers form 8-level deep non-strict stack structure ranging st 0 st 7 registers directly accessed either operand using offset relative top well pushed popped scheme may compared stack frame may pushed/popped indexed instructions push calculate pop values top stack unary operations fsqrt fptan etc implicitly address topmost st 0 binary operations fadd fmul fcom etc implicitly address st 0 st 1 non-strict stack model also allows binary operations use st 0 together direct memory operand explicitly specified stack register st x role similar traditional accumulator combined destination left operand also reversed instruction-by-instruction basis st 0 unmodified operand st x destination furthermore contents st 0 exchanged another stack register using instruction called fxch st x properties make x87 stack usable seven freely addressable registers plus dedicated accumulator seven independent accumulators especially applicable superscalar x86 processors pentium 1993 later exchange instructions codes d9c8..d9cf optimized zero clock penalty using one integer paths fxch st x parallel fpu instruction despite natural convenient human assembly language programmers compiler writers found complicated construct automatic code generators schedule x87 code effectively stack-based interface potentially minimize need save scratch variables function calls compared register-based interface although historically design issues original implementation limited potential x87 provides single-precision double-precision 80-bit double-extended precision binary floating-point arithmetic per ieee 754-1985 standard default x87 processors use 80-bit double-extended precision internally allow sustained precision many calculations see ieee 754 design rationale given sequence arithmetic operations may thus behave slightly differently compared strict single-precision double-precision ieee 754 fpu may sometimes problematic semi-numerical calculations written assume double precision correct operation avoid problems x87 configured using special configuration/status register automatically round single double precision operation since introduction sse2 x87 instructions essential remain important high-precision scalar unit numerical calculations sensitive round-off error requiring 64-bit mantissa precision extended range available 80-bit format clock cycle counts examples typical x87 fpu instructions register-register versions shown ... b notation minimum maximum covers timing variations dependent transient pipeline status arithmetic precision chosen 32 64 80 bits also includes variations due numerical cases number set bits zero etc. l → h notation depicts values corresponding lowest l highest h maximal clock frequencies available companies designed manufactured floating-point units compatible intel 8087 later models include amd 287 387 486dx 5x86 k5 k6 k7 k8 chips technologies super math coprocessors cyrix fasmath cx87slc cx87dlc etc. 6x86 cyrix mii fujitsu early pentium mobile etc harris semiconductor manufactured 80387 486dx processors ibm various 387 486 designs idt winchip c3 c7 nano etc iit 2c87 3c87 etc lc technology green math coprocessors national semiconductor geode gx1 geode gxm etc nexgen nx587 rise technology mp6 st microelectronics manufactured 486dx 5x86 etc texas instruments manufactured 486dx processors etc transmeta tm5600 tm5800 ulsi math·co coprocessors via c3 c7 nano etc xtend 83s87sx-25 coprocessors 8087 first math coprocessor 16-bit processors designed intel built paired intel 8088 8086 microprocessors intel earlier 8231 8232 floating-point processors marketed use i8080 cpu fact licensed versions amd am9511 am9512 fpus 1977 1979 80187 80c187 math coprocessor intel 80186 cpu incapable operating 80188 80188 8-bit data bus 80188 use 8087 80187 appear time 80186 80188 fact launched 80287 80387 although interface main processor 8087 core 80387 thus fully ieee 754-compliant capable executing 80387 extra instructions 80287 i287 math coprocessor intel 80286 series microprocessors intel models included variants specified upper frequency limits ranging 6 12 mhz later followed i80287xl 387 microarchitecture i80287xlt special version intended laptops well variants 80287xl actually 80387sx 287 pinout contains internal 3/2 multiplier motherboards ran coprocessor 2/3 cpu speed could instead run fpu speed cpu 287 models 387-like performance intel 80c287 built using chmos iii amd 80ec287 manufactured amd cmos process using fully static gates 80287 80287xl work 80386 microprocessor initially coprocessors available 80386 introduction 80387 1987 finally able work cyrix cx486slc however chips 80387 strongly preferred higher performance greater capability instruction set 80387 387 i387 first intel coprocessor fully compliant ieee 754-1985 standard released 1987 full two years 386 chip i387 includes much improved speed intel previous 8087/80287 coprocessors improved characteristics trigonometric functions 8087 80287 fptan fpatan instructions limited argument range ±π/4 ±45° 8087 80287 direct instructions sin cos functions without coprocessor 386 normally performs floating-point arithmetic relatively slow software routines implemented runtime software exception handler math coprocessor paired 386 coprocessor performs floating-point arithmetic hardware returning results much faster emulating software library call i387 compatible standard i386 chip 32-bit processor bus later cost-reduced i386sx narrower 16-bit data bus interface i387 32-bit bus i386sx requires coprocessor 80387sx compatible sx narrower 16-bit data bus i487sx p23n marketed floating-point unit coprocessor intel i486sx machines actually contained full-blown i486dx implementation installed i486sx system i487 disabled main cpu took cpu operations i487 took measures detect presence i486sx would function without original cpu place nx587 last fpu x86 manufactured separately cpu case nexgen nx586
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Computer architecture
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yahoo messenger protocol yahoo messenger protocol ymsg underlying network protocol used yahoo messenger instant messaging client yahoo instant messager supports many features beyond messaging including off-line messaging file transfer chat conferencing voice chat webcams avatars ymsg protocol provides language series conventions software communicating yahoo instant messaging service essence ymsg performs role yahoo im http world wide web unlike http however ymsg proprietary protocol closed standard aligned yahoo messaging service rival messaging services protocols based open standards others proprietary effectively fulfilling role different mechanics one fundamental tenets instant messaging notion users see someone connected network—known industry 'presence ymsg protocol uses mechanics standard internet connection achieve presence—the connection uses send receive data order user remain 'visible users service thereby signaling availability yahoo im client software must maintain functional open network connection linking client yahoo im servers organizations block communication port used yahoo im either choose whitelist certain types internet usage web surfing email example seek blacklist instant messaging services yahoo provides alternative route connecting service mimics http protocol used world wide web however http inherent sense persistent connection yahoo instead relies client frequently contacting server order approximate sense connection required give user presence im network originally ymsg login procedure suffered security flaw known replay attack given password authentication information always identically scrambled sent across network allowed attacker witnesses transmission merely reproduce message verbatim order successfully log without actually needing know original password details generated time around 2000 2001 yahoo upgraded service introduce random element login attempt defeating potential replay attacks exception login authentication details data sent ymsg connection encrypted ymsg uses binary format text portions data transmitted plain view therefore difficult attacker seize control yahoo im account quite easy read messages sent account holder along details list friends attacker control one computers data routed ymsg protocol communicates client application server using tcp/ip connection port 5050 default ports may used port blocked alternatively http route available clients behind well-secured firewall http requests used upload messages client downloading messages accumulated server since last request client remains logged long tcp/ip connection kept open case client connected via http client fails send request time 'ping messages sent every thirty seconds ymsg packets consist twenty byte header consists four bytes ymsg two bytes version current version 19 two bytes vendor id typically 0 two bytes packet length content include 20 byte header two bytes service type ymsg packet 4 bytes status related buddy status though used log invisible four bytes session id rest packet variable length table key/value pairs key ascii representation numeric code representing field type value associated data two byte separator hexadecimal values c0 80 used delimit entry table parts ymsg rely protocols example file transfer initially negotiated using ymsg actual transfer file done via http webcams also use ymsg discover request permission view http actually feed jpeg 2000 images one client another chatroom categories rooms lobbies retrieved using http xml documents regular webcam connections use h.323 yahoo voice uses sip calls voip handled indirectly yahoo servers chat client direct access yahoo chat conference voice however use older form audio compression called truespeech developed dsp group chatroom categories retrieved login process multi-step process spans two protocols client successfully establishing tcp connection ymsg server sends authentication packet contains user name user wishes log ymsg server ymsg server responds authentication packet containing challenge string key/value field 96 https process starts connecting login.yahoo.com sending token_get string constructed username password account client trying log https response token login successful contain token string another https request sent login.yahoo.com token_login constructed token successful response contain three strings crumb tcookie ycookie client combines crumb challenge strings performs md5 hash combined string converts resulting 16-byte value base64 string performs negligible amount manipulation resulting base64 string making three character replacements '+ '= '- '/ resultant base64 string used building authenticationresponse packet whose key 307 contains resultant base64 string value client sends authenticationresponse packet authenticationresponse packet successful client receive list listv15 statusv15 newmail ping number y7 buddy authorization message packets offline messages buddy requests list packet contains aliases user accounts yahooid listv15 contains users friends groups ignored user list statusv15 packet contains users listv15 online busy idle well status messages users may potentially string represents resource another http server user display image
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Internet protocols
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source code virus source code viruses subset computer viruses make modifications source code located infected machine source file overwritten includes call malicious code targeting generic programming language c source code viruses portable source code viruses rare partly due difficulty parsing source code programmatically reported exist
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Computer security
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javascript javascript often abbreviated js high-level interpreted scripting language conforms ecmascript specification javascript curly-bracket syntax dynamic typing prototype-based object-orientation first-class functions alongside html css javascript one core technologies world wide web javascript enables interactive web pages essential part web applications vast majority websites use major web browsers dedicated javascript engine execute multi-paradigm language javascript supports event-driven functional imperative including object-oriented prototype-based programming styles apis working text arrays dates regular expressions dom language include i/o networking storage graphics facilities relies upon host environment embedded provide features initially implemented client-side web browsers javascript engines embedded many types host software including server-side web servers databases non-web programs word processors pdf software runtime environments make javascript available writing mobile desktop applications including desktop widgets terms vanilla javascript vanilla js refer javascript extended frameworks additional libraries scripts written vanilla js plain javascript code although similarities javascript java including language name syntax respective standard libraries two languages distinct differ greatly design javascript influenced programming languages self scheme json serialization format used store data structures files transmit across networks based javascript 1993 national center supercomputing applications ncsa unit university illinois urbana-champaign released ncsa mosaic first popular graphical web browser played important part expanding growth nascent world wide web beyond nextstep niche worldwideweb formed three years earlier 1994 company called mosaic communications founded mountain view california employed many original ncsa mosaic authors create mosaic netscape however intentionally shared code ncsa mosaic internal codename company browser mozilla portmanteau mosaic godzilla first version web browser mosaic netscape 0.9 released late 1994 within four months already taken three-quarters browser market became main web browser 1990s avoid trademark ownership problems ncsa browser subsequently renamed netscape navigator year company took name netscape communications netscape communications realized web needed become dynamic marc andreessen founder company believed html needed glue language easy use web designers part-time programmers assemble components images plugins code could written directly web page markup 1995 netscape communications recruited brendan eich goal embedding scheme programming language netscape navigator could get started netscape communications collaborated sun microsystems include sun static programming language java netscape navigator compete microsoft user adoption web technologies platforms netscape communications decided scripting language wanted create would complement java similar syntax excluded adopting languages perl python tcl scheme defend idea javascript competing proposals company needed prototype eich wrote one 10 days may 1995 although developed name mocha language officially called livescript first shipped beta releases netscape navigator 2.0 september 1995 renamed javascript deployed netscape navigator 2.0 beta 3 december final choice name caused confusion giving impression language spin-off java programming language choice characterized marketing ploy netscape give javascript cachet hot new web programming language common misconception javascript influenced earlier web page scripting language developed nombas named cmm confused later c -- created 1997 brendan eich however never heard cmm created livescript nombas pitch embedded web page scripting netscape though web page scripting new concept shown violawww web browser nombas later switched offering javascript instead cmm scriptease product part tc39 group standardized ecmascript december 1995 soon releasing javascript browsers netscape introduced implementation language server-side scripting netscape enterprise server since 1996 iis web-server supported microsoft implementation server-side javascript—jscript—in asp .net pages since mid-2000s additional server-side javascript implementations introduced node.js 2009 microsoft script technologies including vbscript jscript released 1996 jscript reverse-engineered implementation netscape javascript part internet explorer 3 jscript also available server-side scripting internet information server internet explorer 3 also included microsoft first support css various extensions html case implementation noticeably different found netscape navigator time differences made difficult designers programmers make single website work well browsers leading use best viewed netscape best viewed internet explorer logos characterized early years browser wars javascript began acquire reputation one roadblocks cross-platform standards-driven web developers took difficult task trying make sites work major browsers many could afford time release internet explorer 4 microsoft introduced concept dynamic html differences language implementations different proprietary document object models remained obstacles widespread take-up javascript web november 1996 netscape submitted javascript ecma international carve standard specification browser vendors could implement based work done netscape led official release language specification ecmascript published first edition ecma-262 standard june 1997 javascript well known implementations actionscript jscript well-known implementations ecmascript release ecmascript 2 june 1998 continued standards process cycle conforming modifications iso/iec 16262 international standard ecmascript 3 released december 1999 modern-day baseline javascript original ecmascript 4 work led waldemar horwat netscape google started 2000 microsoft initially participated implemented proposals jscript .net language time clear microsoft intention cooperating implementing proper javascript internet explorer even though competing proposal partial diverged point implementation .net server side 2003 original ecmascript 4 work mothballed next major event 2005 two major happenings javascript history first brendan eich mozilla rejoined ecma international not-for-profit member work started ecmascript xml e4x ecma-357 standard came ex-microsoft employees bea systems originally acquired crossgain led working jointly macromedia later acquired adobe systems implementing e4x actionscript 3 actionscript 3 fork original ecmascript 4 along macromedia work restarted ecmascript 4 goal standardizing actionscript 3 end adobe systems released actionscript virtual machine 2 code named tamarin open source project tamarin actionscript 3 different web javascript converge realized parties 2007 2008 alas still turmoil various players douglas crockford—then yahoo —joined forces microsoft 2007 oppose ecmascript 4 led ecmascript 3.1 effort development ecmascript 4 never completed work influenced subsequent versions happening open source developer communities set work revolutionize could done javascript community effort sparked 2005 jesse james garrett released white paper coined term ajax described set technologies javascript backbone used create web applications data loaded background avoiding need full page reloads leading dynamic applications resulted renaissance period javascript usage spearheaded open source libraries communities formed around libraries prototype jquery dojo toolkit mootools others released july 2008 disparate parties either side came together oslo led eventual agreement early 2009 rename ecmascript 3.1 ecmascript 5 drive language forward using agenda known harmony ecmascript 5 finally released december 2009 june 2011 ecmascript 5.1 released fully align third edition iso/iec 16262 international standard ecmascript 2015 released june 2015 ecmascript 2016 released june 2016 current version ecmascript 2017 released june 2017 javascript become one popular programming languages web however many professional programmers initially denigrated language due perceived target audience web authors amateurs advent ajax returned javascript spotlight brought professional programming attention result proliferation comprehensive frameworks libraries improved javascript programming practices increased usage javascript outside web browsers seen proliferation server-side javascript platforms january 2009 commonjs project founded goal specifying common standard library mainly javascript development outside browser rise single-page applications javascript-heavy sites increasingly used compile target source-to-source compilers dynamic languages static languages javascript trademark oracle corporation united states used license technology invented implemented netscape communications current entities mozilla foundation following features common conforming ecmascript implementations unless explicitly specified otherwise popular modern web browsers support javascript built-in interpreters javascript supports much structured programming syntax c e.g. codice_1 statements codice_2 loops codice_3 statements codice_4 loops etc. one partial exception scoping javascript originally function scoping codice_5 ecmascript 2015 added keywords codice_6 codice_7 block scoping meaning javascript function block scoping like c javascript makes distinction expressions statements one syntactic difference c automatic semicolon insertion allows semicolons would normally terminate statements omitted javascript almost entirely object-based javascript object associative array augmented prototype see string key provides name object property two syntactical ways specify name dot notation codice_9 bracket notation codice_10 property may added rebound deleted run-time properties object property belongs object prototype inheritance chain enumerated using codice_11 loop javascript small number built-in objects including codice_12 codice_13 function first-class function considered object function may properties methods codice_23 codice_24 nested function function defined within another function created time outer function invoked addition nested function forms lexical closure lexical scope outer function including constant local variable argument value becomes part internal state inner function object even execution outer function concludes javascript also supports anonymous functions javascript supports implicit explicit delegation javascript officially managed mozilla foundation new language features added periodically however javascript engines support new features variables javascript defined using either codice_5 codice_6 codice_7 keywords var x // declares variable x assigns special value undefined confused undefined value var 2 // declares variable assigns value 2 var z hello world // declares variable z assigns string containing hello world note comments example preceded two forward slashes built-in input/output functionality javascript run-time environment provides ecmascript specification edition 5.1 mentions indeed provisions specification input external data output computed results however runtime environments codice_38 object used print output minimalist hello world program javascript console.log hello world simple recursive function function factorial n factorial 3 // returns 6 anonymous function lambda function counter var closure counter closure // returns 1 closure // returns 2 closure // returns 3 example shows javascript function closures capture non-local variables reference arrow functions first introduced 6th edition ecmascript 2015 shorten syntax writing functions javascript arrow functions anonymous nature variable needed refer order invoke creation example arrow function // arrow functions let us omit function keyword long_example // points anonymous function value const long_example input1 input2 // arrow functions also let us automatically return expression right // arrow input 5 omitting braces return keyword const short_example input input 5 long_example 2 3 // prints hello world returns 5. short_example 2 // returns 7 javascript objects created way functions known function object object example function ball r var myball new ball 5 // creates new instance ball object radius 5 myball.show // instance ball object show function performed variadic function demonstration codice_30 special variable function sum sum 1 2 // returns 3 sum 1 2 3 // returns 6 immediately-invoked function expressions often used create modules ecmascript 2015 built-in module construct language modules allow gathering properties methods namespace making private var counter function // module counter.get // shows 0 counter.set 6 counter.increment // shows 7 counter.increment // shows 8 exporting importing modules javascript export example /* mymodule.js */ // function remains private exported let sum b // export variables export var name 'alice export let age 23 // export named functions export function add num1 num2 // export class export class multiplication import example // import one property import add './mymodule.js console.log add 1 2 // 3 // import multiple properties import name age './mymodule.js console.log name age // alice 23 // import properties module import './module.js' console.log name age // alice 23 console.log add 1,2 // 3 sample code displays various javascript features /* finds lowest common multiple lcm two numbers */ function lcmcalculator x // constructor function // prototype object instances created constructor // constructor prototype property lcmcalculator.prototype // object literal // define generic output function implementation works web browsers function output x // note array map foreach defined javascript 1.6 // used demonstrate javascript inherent functional nature .map function pair // array literal mapping function function printresult obj following output displayed browser window lcmcalculator 28 b 56 gcd 28 lcm 56 lcmcalculator 21 b 56 gcd 7 lcm 168 lcmcalculator 25 b 55 gcd 5 lcm 275 lcmcalculator 22 b 58 gcd 2 lcm 638 94.5 10 million popular web pages used javascript common use javascript add client-side behavior html pages also known dynamic html dhtml scripts embedded included html pages interact document object model dom page simple examples usage javascript code run locally user browser rather remote server increasing application overall responsiveness user actions javascript code also detect user actions html alone individual keystrokes applications gmail take advantage much user-interface logic written javascript javascript dispatches requests information content e-mail message server wider trend ajax programming similarly exploits strength javascript engine also known javascript interpreter javascript implementation interpreter interprets javascript source code executes script accordingly first javascript engine created brendan eich netscape netscape navigator web browser engine code-named spidermonkey implemented c. since updated javascript 1.5 conform ecmascript 3 rhino engine created primarily norris boyd formerly netscape google javascript implementation java rhino like spidermonkey ecmascript 3 compliant web browser common host environment javascript however web browser execute javascript code example text-based browsers javascript engines users browsers may disable scripts preference extension web browser typically creates host objects represent dom javascript web server another common host environment javascript web server would typically expose host objects representing http request response objects javascript program could interrogate manipulate dynamically generate web pages javascript language popular browsers share support inadvertently become target language frameworks languages increasing speed javascript engines made language feasible compilation target despite performance limitations inherent dynamic nature minimal example standards-conforming web page containing javascript using html 5 syntax dom doctype html html /html javascript runs widely varying environments important part testing debugging test verify javascript works across multiple browsers dom interfaces officially defined w3c standardization effort separate javascript implementation dom interfaces differ web browsers javascript authors deal differences writing standards-compliant code executed correctly browsers failing write code behaves differently absence certain browser features authors may also find practical detect browser running two browsers may implement feature differing behavior libraries toolkits take browser differences account also useful programmers furthermore scripts may work users example user may support users web authors try create pages degrade gracefully user agents browsers support page javascript particular page remain usable albeit without extra features javascript would added sites use html codice_40 tag contains alt content js disabled alternative approach many find preferable first author content using basic technologies work browsers enhance content users javascript enabled javascript dom provide potential malicious authors deliver scripts run client computer via web browser authors minimize risk using two restrictions first scripts run sandbox perform web-related actions general-purpose programming tasks like creating files second scripts constrained same-origin policy scripts one web site access information usernames passwords cookies sent another site javascript-related security bugs breaches either origin policy sandbox subsets general javascript—adsafe secure ecmascript ses —that provide greater levels security especially code created third parties advertisements caja another project safe embedding isolation third-party javascript html content security policy main intended method ensuring trusted code executed web page common javascript-related security problem cross-site scripting xss violation same-origin policy xss vulnerabilities occur attacker able cause target web site online banking website include malicious script webpage presented victim script example access banking application privileges victim potentially disclosing secret information transferring money without victim authorization solution xss vulnerabilities use html escaping whenever displaying untrusted data browsers include partial protection reflected xss attacks attacker provides url including malicious script however even users browsers vulnerable xss attacks malicious code stored database correct design web applications server side fully prevent xss xss vulnerabilities also occur implementation mistakes browser authors another cross-site vulnerability cross-site request forgery csrf csrf code attacker site tricks victim browser taking actions user intend target site like transferring money bank target sites rely solely cookies request authentication requests originating code attacker site carry valid login credentials initiating user general solution csrf require authentication value hidden form field cookies authenticate request might lasting effects checking http referrer header also help javascript hijacking type csrf attack codice_29 tag attacker site exploits page victim site returns private information json javascript possible solutions include developers client-server applications must recognize untrusted clients may control attackers application author assume javascript code run intended secret embedded code could extracted determined adversary implications package management systems npm bower popular javascript developers systems allow developer easily manage program dependencies upon developer program libraries developers trust maintainers libraries keep secure date always case vulnerability emerged blind trust relied-upon libraries new releases cause bugs vulnerabilities appear programs rely upon libraries inversely library go unpatched known vulnerabilities wild study done looking sample 133k websites researchers found 37 websites included library at-least one known vulnerability median lag oldest library version used website newest available version library 1,177 days alexa development libraries still active use ceased years ago another possibility maintainer library may remove library entirely occurred march 2016 azer koçulu removed repository npm caused tens thousands programs websites depending upon libraries break javascript provides interface wide range browser capabilities may flaws buffer overflows flaws allow attackers write scripts would run code wish user system code means limited another javascript application example buffer overrun exploit allow attacker gain access operating system api superuser privileges flaws affected major browsers including firefox internet explorer safari plugins video players adobe flash wide range activex controls enabled default microsoft internet explorer may also flaws exploitable via javascript flaws exploited past windows vista microsoft attempted contain risks bugs buffer overflows running internet explorer process limited privileges google chrome similarly confines page renderers sandbox web browsers capable running javascript outside sandbox privileges necessary example create delete files privileges intended granted code web incorrectly granting privileges javascript web played role vulnerabilities internet explorer firefox windows xp service pack 2 microsoft demoted jscript privileges internet explorer microsoft windows allows javascript source files computer hard drive launched general-purpose non-sandboxed programs see windows script host makes javascript like vbscript theoretically viable vector trojan horse although javascript trojan horses uncommon practice 2015 javascript-based proof-of-concept implementation rowhammer attack described paper security researchers 2017 javascript-based attack via browser demonstrated could bypass aslr called aslr⊕cache anc addition web browsers servers javascript interpreters embedded number tools applications provides object model provides access host environment core javascript language remains mostly application within javascript access debugger becomes invaluable developing large non-trivial programs implementation differences various browsers particularly within dom useful access debugger browsers web application targets script debuggers integrated within many mainstream browsers internet explorer firefox safari google chrome opera node.js addition native internet explorer developer tools three debuggers available internet explorer microsoft visual studio features three closely followed microsoft script editor component microsoft office finally free microsoft script debugger free microsoft visual web developer express provides limited version javascript debugging functionality microsoft visual studio comparison internet explorer firefox comprehensive set developer tools includes debugger well old versions firefox without tools used firefox addon called firebug older venkman debugger webkit web inspector includes javascript debugger used safari modified version called blink devtools used google chrome node.js node inspector interactive debugger integrates blink devtools opera includes set tools called dragonfly addition native computer software online javascript integrated development environment ides debugging aids written javascript built run web example program jslint developed douglas crockford written extensively language jslint scans javascript code conformance set standards guidelines many libraries javascript three.js provide links demonstration code edited users demonstration codes also used pedagogical tool institutions khan academy allow students experience writing code environment see output programs without needing setup beyond web browser javascript increased usage web development warrants considerations performance frontend code inherited many responsibilities previously handled backend mobile devices particular may encounter problems rendering poorly optimized frontend code library benchmarks benchmark.js benchmarking library supports high-resolution timers returns statistically significant results another tool jsben.ch online javascript benchmarking tool code snippets tested javascript initially developed 1996 use netscape navigator web browser year microsoft released implementation internet explorer implementation called jscript due trademark issues 1997 first standardized version language released name ecmascript first edition ecma-262 standard explicit versioning opt-in language features mozilla-specific removed later firefox versions least firefox 59 firefox 4 last version referred explicit javascript version 1.8.5 new editions ecma-262 standard javascript language features often mentioned initial definition ecma-262 editions following table explicitly versioned javascript versions based information multiple sources javascript widely supported client-side language run within web browser become intermediate language languages also called transpilers target included newly created languages ports existing languages include javascript unusual limitations – explicit integer type double-precision binary floating point – languages compile javascript take care use integer-converting shift bitwise logical operators may slightly different behavior environments common misconception javascript similar closely related java true c-like syntax c language immediate common ancestor language also typically sandboxed used inside browser javascript designed java syntax standard library mind particular java keywords reserved original javascript javascript standard library follows java naming conventions javascript objects based classes java 1.0 similarities end java javascript first appeared 1995 java developed james gosling sun microsystems javascript brendan eich netscape communications differences two languages prominent similarities java static typing javascript typing dynamic java loaded compiled bytecode javascript loaded human-readable source code java objects class-based javascript prototype-based finally java support functional programming java 8 javascript done beginning influenced scheme starting 2017 web browsers began supporting webassembly technology standardized w3c webassembly standard specifies binary format produced compiler toolchain llvm execute browser near native speed webassembly allows programming languages c c++ c java used well javascript author client-side code world wide web
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Programming language topics
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windows home server 2011 windows home server 2011 code named vail home server operating system microsoft designed small office/home offices homes multiple connected pcs offer protected file storage file sharing automated pc backup remote access remote control pc desktops released 6 april 2011 following release power pack 3 aging predecessor windows home server windows home server 2011 last windows home server release succeeded windows server 2012 essentials windows home server 2011 based windows server 2008 r2 windows 7 requires x86-64 cpus 64-bit predecessor worked older ia-32 32-bit architecture well coupled fundamental changes structure client backups shared folders clear method migrating previous version windows home server 2011 windows home server 2011 includes additional entertainment capabilities 'add feature app store including web-based media functionality initial speculation technology columnist mary jo foley fueled idea 'vail would integrate windows media center prompted response time tell microsoft windows home server product planner todd headrick time public beta microsoft decided integrate windows media center 'vail 23 november 2010 microsoft announced drive extender would removed windows home server 2011 announcement led astonishment outrage testers users criticism drive extender removal mainly related seen core feature windows home server key reason adoption windows home server 2011 developer michael leworthy expressed concern implementation drive extender might lead data error issues result third-party products entered market fill void left drive extender including drive bender division drivepool stablebit volume spanning feature drive extender two drives used one large storage volume available using dynamic disks feature windows server release
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Operating systems
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socket g34 socket g34 land grid array cpu socket designed amd support amd multi-chip module opteron 6000-series server processors g34 launched march 29 2010 alongside initial grouping opteron 6100 processors designed socket g34 supports four ddr3 sdram channels two die 1944 pin cpu package socket g34 available four-socket arrangements change socket f cpus supporting eight-socket arrangements however four socket g34 cpus eight dies identical eight socket f cpus amd declined extend socket g34 eight-way operation citing shrinking demand 4-socket market amd targeting socket g34 high-end two-socket market four-socket market lower-end two-socket market serviced monolithic-die socket c32 cpus half core count equivalent socket g34 cpus socket g34 originally started socket g3 used g3mx expand memory capacity socket g3 g3mx canceled altogether replaced socket g34 socket g34 introduced march 2010 k10-based 8-core 12-core magny-cours opteron 6100 series cpus socket g34 also supports bulldozer-based 4-core 8-core 12-core 16-core opteron 6200 interlagos cpus piledriver-based 4-core 8-core 12-core 16-core opteron 6300 abu dhabi cpus
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Computer architecture
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fdm software fdm fetch/filter deliver mail mail delivery agent email filtering software unix-like operating systems similar fetchmail procmail started 2006 developer later also started tmux 2007. fdm available package many unix-like operating systems included openbsd ports since 2007-01-18 2014 last maintainer procmail posted message openbsd mailing list suggesting remove procmail port suggested well-known openbsd ports maintainer fdm natural alternative procmail port however removed remains place 2019 fdm listed openbsd innovations page section projects maintained openbsd developers outside openbsd
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Operating systems
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xos webtop xos webtop open source webtop os mainly written html5 php javascript xos includes desktop mobile environment features applications system utilities features continuously added accessible windows mac linux ios apple android operating system web browser first version xos webtop started development december 2010 later became available may 14 2011 several months development initial webtop work entirely planned xproduct posted version xos 2.0 desktop edition online public use quickly went back development work would later become xos webtop 3.0 development version follow version 2.0 first started beta testing version release xos 2.0 desktop edition beta reworked ground become entirely new version xos early july beta xos webtop 3.0 came soon xos webtop seen webtop catching market first development updates version fast-paced point rushed resulted sub-par experience many problems continued development desktop edition xos version 3.0 mobile version also released name xos 3.0 mobile continued tested developed well january 5 2012 xproduct released newest version xos desktop edition version 3.1 version includes heavily updated interface fix bugs glitches occurring version 3.0 well slightly improved setup additional features updated mobile edition also version 3.1 released coincide release version 3.1 desktop edition featuring updated interface design previous version version 3.1 first version webtop utilize xproduct new server website updated new domain xproduct.net upon release version 3.1 development cancelled original programmer however code open-sourced development includes fixing bugs uploading fixes soon possible testing make sure program works properly secure unlike earlier versions desktop edition xproduct releasing updates unless actually work tested tablet version xos works add desktop mobile platforms developer page available xos webtop website interested development
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Distributed computing architecture
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nxp coldfire nxp coldfire microprocessor derives motorola 68000 family architecture manufactured embedded systems development nxp semiconductors formerly manufactured freescale semiconductor formerly semiconductor division motorola merged nxp 2015 coldfire instruction set assembly source compatible means translation software available vendor entirely object code compatible 68000 compared classic 68k hardware instruction set differs mainly longer support binary-coded decimal bcd packed data format removes number less used instructions instructions kept support fewer addressing modes also floating point intermediates 64 bits 80 bits 68881 68882 coprocessors instructions 16 32 48 bits long simplification compared 68000 series february 1999 μclinux project linux kernel ported two coldfire processors mcf5206 mcf5307 2006 debian project looking making m68k port compatible coldfires coldfire models clocked high 300 mhz much faster 68060 officially reach 75 mhz overclocked 110 mhz stallion technologies epipe secure computing snapgear security appliances arcturus networks system module products based coldfire processors coldfire linux-based single-board computers sbc ethernet compactflash small 23×55 mm 45×45 mm based compactflash 37×43 mm coldfire based products even deployed international space station electronic nose project five generations versions coldfire available freescale also fido 1100 microcontroller launched 2007 aimed predictable embedded control systems industrial ethernet applications using 68k/cpu32 instruction set however fido unique architecture shares instruction set 68k november 2006 freescale announced coldfire microprocessor cores available license semiconductor intellectual property ip licensing support partner ipextreme inc. coldfire v1 core available free license per use royalty altera cyclone-iii fpga september 2007 freescale launched 32-bit flexis microcontroller family coldfire cpu core june 2010 freescale announced coldfire+ line coldfire v1 core using 90 nm tfs technology 2010 freescale also launched kinetis arm-based product line leading industry observers speculate future coldfire range given freescale would several competing cpu ranges
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Computer architecture
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alfred aho alfred vaino aho born august 9 1941 canadian computer scientist best known work programming languages compilers related algorithms textbooks art science computer programming aho received b.a.sc engineering physics university toronto ph.d. electrical engineering/computer science princeton university conducted research bell labs 1967 1991 1997 2002 vice president computing sciences research center holds lawrence gussman chair computer science columbia university served chair department 1995 1997 spring 2003 phd thesis aho created indexed grammars nested-stack automaton vehicles extending power context-free languages retaining many decidability closure properties indexed grammars used model parallel rewriting systems particularly biological applications graduating princeton aho joined computing sciences research center bell labs devised efficient regular expression string-pattern matching algorithms implemented first versions unix tools codice_1 codice_2 codice_2 algorithm become known aho-corasick algorithm used several bibliographic search-systems including one developed margaret j. corasick string-searching applications bell labs aho worked closely steve johnson jeffrey ullman develop efficient algorithms analyzing translating programming languages steve johnson used bottom-up lalr parsing algorithms create syntax-analyzer generator yacc michael e. lesk eric schmidt used aho regular-expression pattern-matching algorithms create lexical-analyzer generator lex lex yacc tools derivatives used develop front ends many today programming language compilers aho ullman wrote series textbooks compiling techniques codified theory relevant compiler design 1977 textbook principles compiler design green dragon front cover became known green dragon book 1986 aho ullman joined ravi sethi create new edition red dragon book briefly shown 1995 movie hackers 2007 also monica lam create purple dragon book dragon books widely used compiler textbooks throughout world 1974 aho john hopcroft ullman wrote design analysis computer algorithms codifying early research algorithms book became one highly cited books computer science several decades helped stimulate creation algorithms data structures central course computer science curriculum aho also widely known co-authorship awk programming language peter j. weinberger brian kernighan stands aho aho research interests include programming languages compilers algorithms quantum computing part language compilers research-group columbia university overall works cited 81,040 times h-index 66 may 8 2019 aho received many prestigious honors including ieee john von neumann medal membership national academy engineering elected fellow american academy arts sciences 2003 holds honorary doctorates university waterloo university helsinki university toronto fellow american association advancement science acm bell labs ieee aho twice served chair advisory committee computer information science engineering directorate national science foundation past president acm special interest group algorithms computability theory aho taught columbia university city new york since 1995 great teacher award society columbia graduates 2003
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Programming language topics
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adobe coldfusion builder adobe coldfusion builder name adobe eclipse-based development ide used build applications coldfusion product original codename bolt reference original lightning icon coldfusion allaire days 2010 adobe released product officially renamed adobe coldfusion builder often referred cfbuilder coldfusion builder became available march 22 2010 along flash builder 4 features include coldfusion builder 2.0 codename storm confirmed previewed adobe max 2010 adobe major features include improved code navigation searching improvements code formatting automatic method stub creation product officially released may 3 2011 new features coldfusion builder 3.0 codename thunder officially released april 29 2014 new features coldfusion builder 2016 3.1.3.300344 officially released february 16 2016
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Programming language topics
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register renaming computer architecture register renaming technique abstracts logical registers physical registers every logical register set physical registers associated programmer assembly language refers instance logical register codice_1 processor transposes name one specific physical register fly physical registers opaque referenced directly via canonical names technique used eliminate false data dependencies arising reuse registers successive instructions real data dependencies elimination false data dependencies reveals instruction-level parallelism instruction stream exploited various complementary techniques superscalar out-of-order execution better performance register machine programs composed instructions operate values instructions must name values order distinguish one another typical instruction might say “ add formula_1 formula_2 put result formula_3 ” instruction formula_1 formula_2 formula_3 names storage locations order compact instruction encoding processor instruction sets small set special locations referred special names registers example x86 instruction set architecture 8 integer registers x86-64 16 many riscs 32 ia-64 128 smaller processors names locations correspond directly elements register file different instructions may take different amounts time example processor may able execute hundreds instructions single load main memory progress shorter instructions executed load outstanding finish first thus instructions finishing original program order out-of-order execution used recent high-performance cpus achieve speed gains consider piece code running out-of-order cpu instructions final three lines independent first three instructions processor finish r1 ≔ 2048 preceding 1032 ≔ r1 done otherwise would write wrong value restriction eliminated changing names registers last three instruction executed parallel first three program run faster obliterating stalling due false data dependency many high-performance cpus implement renaming hardware achieve additional parallelism targets without appropriate data-flow detection good compilers would detect independent instruction sequences choose different registers code generation one instruction references particular location operand either reading input writing output executing instructions order different original program order lead three kinds data hazards instead delaying write reads completed two copies location maintained old value new value reads precede program order write new value provided old value even reads follow write provided new value false dependency broken additional opportunities out-of-order execution created reads need old value satisfied discarded essential concept behind register renaming anything read written renamed general-purpose floating-point registers discussed flag status registers even individual status bits commonly renamed well memory locations also renamed although commonly done extent practiced register renaming transmeta crusoe processor gated store buffer form memory renaming programs refrained reusing registers immediately would need register renaming instruction sets e.g. ia-64 specify large numbers registers specifically reason however limitations approach code size increases important program code larger instruction cache misses often processor stalls waiting new instructions machine language programs specify reads writes limited set registers specified instruction set architecture isa instance alpha isa specifies 32 integer registers 64 bits wide 32 floating-point registers 64 bits wide architectural registers programs written processors running alpha instruction set specify operations reading writing 64 registers programmer stops program debugger observe contents 64 registers status registers determine progress machine one particular processor implements isa alpha 21264 80 integer 72 floating-point physical registers alpha 21264 chip 80 physically separate locations store results integer operations 72 locations store results floating point operations following text describes two styles register renaming distinguished circuit holds data ready execution unit renaming schemes machine converts architectural registers referenced instruction stream tags architectural registers might specified 3 5 bits tags usually 6 8 bit number rename file must read port every input every instruction renamed every cycle write port every output every instruction renamed every cycle size register file generally grows square number ports rename file usually physically large consumes significant power tag-indexed register file style one large register file data values containing one register every tag example machine 80 physical registers would use 7 bit tags 48 possible tag values case unused style instruction issued execution unit tags source registers sent physical register file values corresponding tags read sent execution unit reservation station style many small associative register files usually one inputs execution unit operand instruction issue queue place value one register files style instruction issued execution unit register file entries corresponding issue queue entry read forwarded execution unit reorder buffers data-less data-ful willamette rob rob entries point registers physical register file prf also contain book keeping also first order design done andy glew illinois harrm p6 rob rob entries contain data separate prf data values rob copied rob rrf retirement one small detail temporal locality rob entries i.e. instructions close together von neumann instruction sequence write back close together time may possible perform write combining rob entries fewer ports separate rob/prf would clear makes difference since prf banked robs usually n't associative logic certainly none robs designed andy glew cams keith diefendorff insisted robs complex associative logic many years first rob proposal may cams renaming style used mips r10000 alpha 21264 fp section amd athlon renaming stage every architectural register referenced read write looked architecturally-indexed remap file file returns tag ready bit tag non-ready queued instruction write yet executed read operands tag takes place architectural register instruction every register write new tag pulled free tag fifo new mapping written remap file future instructions reading architectural register refer new tag tag marked unready instruction yet executed previous physical register allocated architectural register saved instruction reorder buffer fifo holds instructions program order decode graduation stages instructions placed various issue queues instructions executed tags results broadcast issue queues match tags tags non-ready source operands match means operand ready remap file also matches tags mark corresponding physical registers ready operands instruction issue queue ready instruction ready issue issue queues pick ready instructions send various functional units cycle non-ready instructions stay issue queues unordered removal instructions issue queues make large power-consuming issued instructions read tag-indexed physical register file bypassing just-broadcast operands execute execution results written tag-indexed physical register file well broadcast bypass network preceding functional unit graduation puts previous tag written architectural register free queue reused newly decoded instruction exception branch misprediction causes remap file back remap state last valid instruction via combination state snapshots cycling previous tags in-order pre-graduation queue since mechanism required since recover remap state state instruction currently graduated branch mispredictions handled branch reaches graduation potentially hiding branch misprediction latency style used integer section amd k7 k8 designs renaming stage every architectural register referenced reads looked architecturally-indexed future file rename file future file read gives value register outstanding instruction yet write i.e. ready instruction placed issue queue values read future file written corresponding entries reservation stations register writes instruction cause new non-ready tag written rename file tag number usually serially allocated instruction order—no free tag fifo necessary tag-indexed scheme issue queues wait non-ready operands see matching tag broadcasts unlike tag-indexed scheme matching tags cause corresponding broadcast value written issue queue entry reservation station issued instructions read arguments reservation station bypass just-broadcast operands execute mentioned earlier reservation station register files usually small perhaps eight entries execution results written reorder buffer reservation stations issue queue entry matching tag future file last instruction target architectural register case register marked ready graduation copies value reorder buffer architectural register file sole use architectural register file recover exceptions branch mispredictions exceptions branch mispredictions recognized graduation cause architectural file copied future file registers marked ready rename file usually way reconstruct state future file instruction intermediate decode graduation usually way early recovery branch mispredictions schemes instructions inserted in-order issue queues removed out-of-order queues collapse empty slots either many unused entries require sort variable priority encoding multiple instructions simultaneously ready go queues collapse holes simpler priority encoding require simple large circuitry advance instructions queue reservation stations better latency rename execute rename stage finds register values directly rather finding physical register number using find value latency shows component branch misprediction latency reservation stations also better latency instruction issue execution local register file smaller large central file tag-indexed scheme tag generation exception processing also simpler reservation station scheme discussed physical register files used reservation stations usually collapse unused entries parallel issue queue serve makes register files larger aggregate consume power complicated simpler register files used tag-indexed scheme worse yet every entry reservation station written every result bus reservation-station machine e.g. 8 issue queue entries per functional unit typically 9 times many bypass networks equivalent tag-indexed machine consequently result forwarding consumes much power area tag-indexed design furthermore reservation station scheme four places future file reservation station reorder buffer architectural file result value stored whereas tag-indexed scheme one physical register file results functional units broadcast storage locations must reach much larger number locations machine tag-indexed scheme function consumes power area time still machines equipped accurate branch prediction schemes execute latencies major concern reservation stations work remarkably well ibm system/360 model 91 early machine supported out-of-order execution instructions used tomasulo algorithm uses register renaming power1 first microprocessor used register renaming out-of-order execution 1990 original r10000 design neither collapsing issue queues variable priority encoding suffered starvation problems result—the oldest instruction queue would sometimes issued instruction decode stopped completely lack rename registers every instruction issued later revisions design starting r12000 used partially variable priority encoder mitigate problem early out-of-order machines separate renaming rob/prf storage functions matter earliest sohi ruu metaflow dcaf combined scheduling renaming storage structure modern machines renaming ram indexing map table logical register number e.g. p6 future files data storage structure however earlier machines used content-addressable memory cam renamer e.g. hpsm rat register alias table essentially used cam logical register number combination different versions register many ways story out-of-order microarchitecture cams progressively eliminated small cams useful large cams impractical p6 microarchitecture first microarchitecture intel implement out-of-order execution register renaming p6 microarchitecture used pentium pro pentium ii pentium iii pentium core core 2 microprocessors cyrix m1 released october 2 1995 first x86 processor use register renaming out-of-order execution x86 processors nexgen nx686 amd k5 released 1996 also featured register renaming out-of-order execution risc μ-operations rather native x86 instructions
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Computer architecture
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merge module merge module special kind windows installer database contains components needed install discrete software bundle merge module installed alone must merged standard windows installer installation creation installation typically merge module collection merge modules related dependencies installs software product portion product runtime purpose merge modules let add self-contained software modules multiple installations example number applications require specifically configured component would possible create merge module installs configures component merge module could added installation packages product required particular component saves effort individually add necessary files registry entries components every installation also saves time updates needed instead updating installations applications merge module updated installations need rebuilt standard merge modules .msm file extension merge modules may configurable merge modules merge modules contain certain values set specify module behaves installation example author configurable merge module may allow attributes set components enable disable isolated components specify bitmap dialog specify custom action run configurable merge modules supported windows installer 2.0 higher exist number pre-created merge modules install commonly used microsoft software packages mdac activex controls mfc sapi dcom
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Operating systems
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powerpc 970 powerpc 970 powerpc 970fx powerpc 970gx powerpc 970mp 64-bit powerpc processors ibm introduced 2002 used powerpc-based macintosh computers apple referred powerpc g5 970 family created collaboration ibm apple project went codename gp-ul giga processor ultra light giga processor codename power4 core derived apple introduced power mac g5 stated five-year collaborative effort multiple future generations short-lived apple retract promise deliver 3 ghz processor one year introduction ibm could never get power consumption far enough processors fit portable computer apple used three variants processor ibm ’ js20/js21 blade modules low-end workstations system p servers based powerpc 970 also used high end embedded systems like mercury ’ momentum xsa-200 ibm also licensing powerpc 970 core use custom applications powerpc 970 single core derivative power4 process 32-bit 64-bit powerpc instructions natively hardware prefetch unit three way branch prediction unit like power4 front-end nine stages long powerpc 970 fetch decode eight instructions dispatch five reserve stations issue eight execution units retire five per cycle execution pipelines lengthened compared power4 achieve higher clock frequencies eight execution units two arithmetic logic units alus two double precision floating-point units two load/store units two altivec units one altivec units executes integer floating-point instructions permute instructions latter three subunits simple integer complex integer floating-point instructions units pipelines varying lengths 10 stages simple integer permute instructions 13 stages complex integer instructions 16 stage floating-point instructions processor two unidirectional 32-bit double data rate ddr buses one reads writes system controller chip northbridge running one quarter processor core speed buses also carry addresses control signals addition data percentage peak bandwidth realized 6.4 gb/s 450 mhz buses unidirectional direction realize half aggregate bandwidth 3.2 gb/s powerpc 970 announced ibm october 2002 released apple computer power mac g5 june 2003 keeping previous naming conventions apple termed powerpc 970 based products g5 fifth generation powerpc microprocessors ibm released first powerpc 970 blade servers bladecenter js20 november 2003 powerpc 970 512 kb full-speed l2 cache clock speeds 1.6 2.0 ghz front side bus ran half processor clock speed powerpc 970fx used 90 nm manufacturing process maximum power rating 11 watts 149 degrees fahrenheit 65 °c clocked 1 ghz maximum 48 watts 2 ghz powerpc 970 pipeline lengthened 9 stages 16 21 stages powerpc 970 fx 10 functional units 2 fixed-point units 2 load/store units 2 floating point units 1 branch unit 1 simd alu unit 1 simd permute unit 1 condition register supports 215 instructions in-flight 16 instruction fetch unit 67 instruction decode unit 100 functional units 32 store queue 64 kbytes directly-mapped instruction cache 32 kbytes d-cache apple released 970fx-powered machines throughout 2004 xserve g5 january power mac g5 june imac g5 august power mac introduced top clock speed 2.5 ghz liquid-cooled eventually reaching high 2.7 ghz april 2005 imac ran front side bus third clock speed despite intense user demand faster laptop cpu g4 apple never used g5 series cpu powerbook laptops original 970 used far much power never seriously viewed candidate portable computer 970fx reduced thermal design power tdp 30 w 1.5 ghz figure led many users believe powerbook g5 might possible however several obstacles prevented even 970fx used application 1.5 ghz g5 substantially faster 1.5 1.67 ghz g4 processors apple used powerbooks instead furthermore northbridge chips available interface 970fx memory devices designed portable computers consumed much power finally 970fx inadequate power saving features portable cpu minimum idle power much high would led poor battery life figures notebook computer ibm announced powerpc 970mp code-named antares 7 july 2005 power everywhere forum tokyo 970mp dual-core derivative 970fx clock speeds 1.2 2.5 ghz maximum power usage 75 w 1.8 ghz 100 w 2.0 ghz core 1 mb l2 cache twice 970fx like 970fx chip produced 90 nm process one cores idle enter doze state shut 970mp also includes partitioning virtualization features powerpc 970mp replaced powerpc 970fx apple high-end power mac g5 computers imac g5 legacy pci-x power mac g5 continued use powerpc 970fx processor powerpc 970mp used ibm js21 blade modules ibm intellistation power 185 workstation ydl powerstation due high power requirements ibm chosen discontinue parts running faster 2.0 ghz powerpc 970gx cancelled single-core version powerpc 970mp featured 1 mb l2 cache would available frequencies 1.2 3 ghz power dissipation would 16 w 1.6 ghz 85 w 3 ghz fabricated 90 nm fabrication process 970mp illustrations different generations 970 processors manufactured ibm east fishkill plant new york white ceramic substrate typical ibm high end processors era two dedicated northbridges powerpc 970-based computers manufactured ibm also cancelled cpc965 northbridge slated release 2007 uniprocessor-only northbridge features 533 mhz ddr2 controller supported 8 gb ecc memory 8x pcie bus integrated four-port gigabit ethernet ipv4 tcp/udp offloading usb 2.0 ports flash-interface northbridge contains integrated powerpc 405 core provide system management configuration capabilities ibm uses proprietary elastic interface bus modules
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Computer architecture
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exploit computer security exploit english verb exploit meaning use something one ’ advantage piece software chunk data sequence commands takes advantage bug vulnerability cause unintended unanticipated behavior occur computer software hardware something electronic usually computerized behavior frequently includes things like gaining control computer system allowing privilege escalation denial-of-service dos related ddos attack several methods classifying exploits common exploit communicates vulnerable software remote exploit works network exploits security vulnerability without prior access vulnerable system local exploit requires prior access vulnerable system usually increases privileges person running exploit past granted system administrator exploits client applications also exist usually consisting modified servers send exploit accessed client application exploits client applications may also require interaction user thus may used combination social engineering method another classification action vulnerable system unauthorized data access arbitrary code execution denial service examples many exploits designed provide superuser-level access computer system however also possible use several exploits first gain low-level access escalate privileges repeatedly one reaches highest administrative level often called root exploit made known authors affected software vulnerability often fixed patch exploit becomes unusable reason black hat hackers well military intelligence agencies hackers publish exploits keep private exploits unknown everyone people found developed referred zero day exploits exploitations commonly categorized named type vulnerability exploit see vulnerabilities list whether local/remote result running exploit e.g eop dos spoofing pivoting refers method used penetration testers uses compromised system attack systems network avoid restrictions firewall configurations may prohibit direct access machines example attacker compromises web server corporate network attacker use compromised web server attack systems network types attacks often called multi-layered attacks pivoting also known island hopping pivoting distinguished proxy pivoting vpn pivoting proxy pivoting generally describes practice channeling traffic compromised target using proxy payload machine launching attacks computer type pivoting restricted certain tcp udp ports supported proxy vpn pivoting enables attacker create encrypted layer tunnel compromised machine route network traffic target machine example run vulnerability scan internal network compromised machine effectively giving attacker full network access behind firewall typically proxy vpn applications enabling pivoting executed target computer payload software exploit pivoting usually done infiltrating part network infrastructure example vulnerable printer thermostat using scanner find devices connected attack attacking vulnerable piece networking attacker could infect network gain complete control
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Computer security
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bad command file name bad command file name common confusing error message ms-dos operating systems command.com primary user interface ms-dos produces error message first word command could interpreted ms-dos word must name internal command executable file batch file error message provided accurate description problem easily confused novices though source error often mistyped command wording gave impression files named later words damaged illegal filenames later wording error message changed clarity windows nt displays following error message instead foo replaced word causing error early unix shells produced equally cryptic reasons modern shells produce error message similar
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Computer architecture
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deforestation computer science theory programming languages computer science deforestation also known fusion program transformation eliminate intermediate lists tree structures created immediately consumed program term deforestation originally coined philip wadler 1990 paper deforestation transforming programs eliminate trees deforestation typically applied programs functional programming languages particularly non-strict programming languages haskell one particular algorithm deforestation shortcut deforestation implemented glasgow haskell compiler deforestation closely related escape analysis
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Programming language topics
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michael wertheimer michael wertheimer born february 6 1957 cryptologic mathematician october 31 2005 june 2009 assistant deputy director chief technology officer office director national intelligence analysis wertheimer oversaw coordination intelligence community efforts bring increased depth accuracy analysis technology 2008 wertheimer successfully launched a-space u.s. intelligence community facebook spies new social network opened september 2008 u.s. intelligence analysts covert operatives across 16 intelligence agencies share information continues advocate intelligence community reforms currently involved pressing adoption intellipedia classified wiki prior appointment wertheimer spent two years industry building research group focused intelligence community 1982 2003 cryptologic mathematician national security agency 1999 selected technical director data acquisition office nsa ’ signals intelligence directorate co-author 2001 signals intelligence strategy 2002 sigint architecture model wertheimer returned national security agency june 2009 june 2010 became current director research 2014 retired nsa works university maryland wertheimer received b.a degrees mathematics philosophy university rochester also received m.a ph.d. degrees mathematics university pennsylvania wertheimer married christina grot may 16 1993 two children daniel born may 13 1996 marissa born november 17 1993
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Computer security
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lan manager lan manager network operating system nos available multiple vendors developed microsoft cooperation 3com corporation designed succeed 3com 3+share network server software ran atop heavily modified version ms-dos lan manager based os/2 operating system co-developed ibm microsoft originally used server message block protocol atop either netbios frames protocol nbf specialized version xerox network systems xns protocol legacy protocols inherited previous products ms-net ms-dos xenix-net ms-xenix afore-mentioned 3+share version lan manager unix-based systems called lan manager/x also available 1990 microsoft announced lan manager 2.0 host improvements including support tcp/ip transport protocol last version lan manager 2.2 included ms-os/2 1.31 base operating system remained microsoft strategic server system release windows nt advanced server 1993 many vendors shipped licensed versions including lan manager authentication uses particularly weak method hashing user password known lm hash algorithm stemming mid 1980s floppy viruses major concern opposed potentially high-frequency attacks feedback high-bandwidth network makes hashes crackable matter seconds using rainbow tables hours using brute force use windows nt replaced ntlm older versions still vulnerable rainbow tables less vulnerable brute force attacks ntlm used logon local accounts except domain controllers since windows vista later versions longer maintain lm hash default kerberos used active directory environments major weaknesses lan manager authentication protocol lm hash also known lanman hash lan manager hash compromised password hashing function primary hash microsoft lan manager microsoft windows versions prior windows nt used store user passwords support legacy lan manager protocol continued later versions windows backward compatibility recommended microsoft turned administrators windows vista protocol disabled default continues used non-microsoft smb implementations lm hash computed follows although based des well-studied formerly secure block cipher lm hash true one-way function password determined hash several weaknesses design firstly passwords limited maximum 14 characters giving theoretical maximum keyspace formula_3 95 ascii printable characters secondly passwords longer 7 characters divided two pieces piece hashed separately weakness allows half password attacked separately exponentially lower cost whole formula_4 different 7-character password pieces possible character set mounting brute-force attack half separately modern desktop machines crack alphanumeric lm hashes hours addition lower case letters password changed upper case password hashed reduces key space half formula_5 lm hash also use cryptographic salt standard technique prevent pre-computed dictionary attacks time–memory tradeoff cryptanalysis attack rainbow table therefore feasible addition password shorter 8 characters result hashing 7 null bytes yielding constant value codice_5 hence making easy identify short passwords sight 2003 ophcrack implementation rainbow table technique published specifically targets weaknesses lm encryption includes pre-computed data sufficient crack virtually alphanumeric lm hashes seconds many cracking tools e.g rainbowcrack l0phtcrack cain incorporate similar attacks make cracking lm hashes fast trivial final weakness lm hashes lies implementation — since change user changes password used carry pass hash attack address security weaknesses inherent lm encryption authentication schemes microsoft introduced ntlmv1 protocol 1993 windows nt 3.1 hashing ntlm uses unicode support replacing codice_6 codice_7 require padding truncating would simplify key negative side des algorithm used 56-bit encryption subsequent authentication steps still salting furthermore windows machines many years configured default send accept responses derived lm hash ntlm hash use ntlm hash provided additional security weaker hash still present also took time artificial restrictions password length management tools user manager lifted lan manager considered obsolete current windows operating systems use stronger ntlmv2 kerberos authentication methods windows systems windows vista/windows server 2008 enabled lan manager hash default backward compatibility legacy lan manager windows earlier clients legacy netbios-enabled applications many years considered good security practice disable compromised lm ntlmv1 authentication protocols n't needed starting windows vista windows server 2008 microsoft disabled lm hash default feature enabled local accounts via security policy setting active directory accounts applying setting via domain group policy method used turn feature windows 2000 windows xp nt users also prevent lm hash generated password using password least fifteen characters length ntlm hashes turn become vulnerable recent years various attacks effectively make weak today lanman hashes back 1998 many legacy third party smb implementations taken considerable time add support stronger protocols microsoft created replace lm hashing open source communities supporting libraries first reverse engineer newer protocols—samba took 5 years add ntlmv2 support jcifs took 10 years poor patching regimes subsequent software releases supporting feature becoming available contributed organisations continuing use lm hashing environments even though protocol easily disabled active directory lastly prior release windows vista many unattended build processes still used dos boot disk instead windows pe start installation windows using winnt.exe something requires lm hashing enabled legacy lan manager networking stack work
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Operating systems
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jane silber jane silber board member canonical ltd. chief executive officer 2010 2017 silber also chair board sensible code company whose products include quickcode silber joined canonical july 2004 work included leading ubuntu one project ensuring large organizations find ubuntu enterprise-ready partially attributes increasing attention user research design open source since 2009 canonical leadership area silber announced transition ceo role april 2017 canonical founder mark shuttleworth resuming position july 2017 silber earlier roles include vice president interactive television company vice president general dynamics c4 systems also worked japan teijin ltd conducting artificial intelligence research product development us general health health risk assessment firm holds mba degree oxford university saïd business school msc degree management technology vanderbilt university concentrated machine learning artificial intelligence work bsc degree mathematics computer science haverford college
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Operating systems
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eugene schultz eugene schultz 1946 2011 american computer security researcher expert cybersecurity schultz born september 10 1946 chicago e. eugene sr. elizabeth schultz married cathy brown 36 years couple three daughters died stroke october 2 2011 completed bachelor degree ucla later earned ms phd cognitive sciences purdue university founder u.s. department energy computer incident advisory capability ciac managed several years chief technology officer emagined security authored several books papers computer security editor-in-chief computers security oldest journal computing security adjunct professor several universities winner department energy excellence award
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Computer security
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security modes generally security modes refer information systems security modes operations used mandatory access control mac systems often systems contain information various levels security classification mode operation determined mode operation users must users access data system high mode operation users must users access data based need know mode operation users must users access data based need know formal access approval multilevel security mode operation also called controlled security mode users must users access data based need know clearance formal access approval
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Computer security
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lotusscript lotusscript object oriented programming language used lotus notes since version 4.0 ibm lotus software products lotusscript similar visual basic developers familiar one easily understand syntax structure code major differences two respective integrated development environments product-specific object classes provided language included vb includes richer set classes ui manipulation whereas lotusscript includes richer set application-specific classes lotus notes lotus word pro lotus 1-2-3 case lotus notes classes work notes databases documents records databases etc classes also used ole automation objects outside lotus notes environment visual basic lotusscript also allows definition user-defined types classes although possible inherit product-specific classes lotusscript programs access microsoft office documents using ole automation libraries ms office
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Programming language topics
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microsoft forefront threat management gateway microsoft forefront threat management gateway forefront tmg formerly known microsoft internet security acceleration server isa server network router firewall antivirus program vpn server web cache microsoft corporation runs windows server works inspecting network traffic passes microsoft forefront tmg offers set features include microsoft forefront threat management gateway product line originated microsoft proxy server developed code-name catapult microsoft proxy server v1.0 first launched january 1997 designed run windows nt 4.0 microsoft proxy server v1.0 basic product designed provide internet access clients lan environment via tcp/ip support also provided ipx/spx networks primarily used legacy novell netware environments winsock translation/tunnelling client allowed tcp/ip applications web browsers operate transparently without tcp/ip wire although well-integrated windows nt4 microsoft proxy server v1.0 basic functionality came one edition extended support microsoft proxy server v1.0 ended 31 march 2002 microsoft proxy server v2.0 launched december 1997 included better nt account integration improved packet filtering support support wider range network protocols microsoft proxy server v2.0 exited extended support phase reached end life 31 december 2004 18 march 2001 microsoft launched microsoft internet security acceleration server 2000 isa server 2000 isa server 2000 introduced standard enterprise editions enterprise-grade functionality high-availability clustering included standard edition isa server 2000 required windows 2000 edition also run windows server 2003 accordance microsoft support lifecycle policy isa server 2000 first isa server product use 10 year support lifecycle 5 years mainstream support five years extended support isa server 2000 reached end life 12 april 2011 microsoft internet security acceleration server 2004 isa server 2004 released 8 september 2004 isa server 2004 introduced multi-networking support integrated virtual private networking configuration extensible user authentication models application layer firewall support active directory integration securenat improved reporting management features rules based configuration also considerably simplified isa server 2000 version isa server 2004 enterprise edition included array support integrated network load balancing nlb cache array routing protocol carp one core capabilities isa server 2004 dubbed secure server publishing ability securely expose internal servers internet example organizations use isa server 2004 publish microsoft exchange server services outlook web access owa outlook mobile access oma activesync using forms-based authentication fba authentication type isa server used pre-authenticate web clients traffic unauthenticated clients published servers allowed isa server 2004 available two editions standard enterprise enterprise edition contains features enabling policies configured array level rather individual isa servers load-balancing across multiple isa servers edition isa server licensed per processor version included windows small business server 2000/2003 premium includes licensing 2 processors isa server 2004 runs windows server 2003 standard enterprise edition appliance hardware containing windows server 2003 appliance edition isa server standard edition available variety microsoft partners microsoft internet security acceleration server 2006 isa server 2006 released 17 october 2006 updated version isa server 2004 retains features isa server 2004 except message screener isa server 2006 introduced new features including isa server appliance edition microsoft also offered isa server 2006 appliance edition designed pre-installed onto oem hardware server appliances sold hardware manufacturers stand-alone firewall type device along appliance edition isa server 2006 standard edition enterprise edition available preconfigured hardware microsoft forefront threat management gateway medium business edition forefront tmg mbe next version isa server also included windows essential business server version runs 64-bit edition windows server 2008 support enterprise edition features array support enterprise policy mainstream support forefront tmg mbe ended november 12 2013 microsoft forefront threat management gateway 2010 forefront tmg 2010 released 17 november 2009 built foundation isa server 2006 provides enhanced web protection native 64-bit support support windows server 2008 windows server 2008 r2 malware protection bits caching service pack 1 product released 23 june 2010 includes several new features support windows server 2008 r2 sharepoint 2010 lines products service pack 2 product released 10 october 2011 9 september 2012 microsoft announced development take place forefront threat management gateway 2010 product longer available purchase 1 december 2012 mainstream support ceased 14 april 2015 extended support end 14 april 2020
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Computer security
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iphone xr iphone xr stylized marketed iphone roman numeral x pronounced ten smartphone designed manufactured apple inc twelfth generation iphone announced phil schiller september 12 2018 steve jobs theater apple park campus alongside higher-priced iphone xs iphone xs max pre-orders began october 19 2018 official release october 26 2018 phone 6.1-inch liquid retina lcd display apple claims advanced lcd industry least expensive device apple iphone x line devices starting price 749 united states 1029 canada £749 united kingdom €849 eurozone countries 6499 yuan china features processor xs xs max apple a12 bionic chip built 7 nanometer process apple claims smartest powerful chip ever put smartphone available six colors black white capri yellow coral shade pink orange product red xr available three storage capacities 64gb 128gb 256gb second iphone released yellow capri first iphone 5c 2013 internationally phone supports dual sims nano-sim esim mainland china hong kong macau dual nano-sim single tray offered instead despite receiving criticism lower display resolution comparison previous iphone models roughly price point xr received mostly positive reviews critics users release xr apple best selling 2018 model according apple xr battery lasts one-and-a-half hours longer direct predecessor iphone 8 xr similar design iphone x iphone xs however slightly larger bezels aluminum frame available wide variety colors similar x-branded iphones models come black front xr ip67 rating dust water resistance means immersed 1-meter deep water 30 minutes xr similar hardware xs features removed reduce price instead 3d touch xr comes haptic touch user long presses feel vibration taptic engine xr also lcd display known liquid retina instead oled screen used x xs xs max display xr resolution 1792×828 pixels pixel density 326 ppi compared 458 ppi x-branded iphones screen-to-body ratio xr 79.3 much higher 67.5 iphone 8 plus still lower phones price category unlike phones x-series xr ships single camera rear phone featuring exactly main camera sensor xs xs max utilizing 1/2.55 sensor size 1.4μm pixel size unlike xs optical zoom single camera dxomark gave camera iphone xr rating 101 giving title “ top-ranked single-lens phone. ” despite rear single-camera setup modified version portrait mode included works unaltered using truedepth front camera rear camera attempts calculate depth field using combination focus pixels image sensor ai resulting limitations including lower resolution depth data subjects close enough due wide-angle lens used instead missing telephoto lens like iphone xs xs max iphone xr also offers adjustable depth field software allowing user adjust background bokeh effect taking photo xr shipped ios 12 installed box compatible ios 13
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Operating systems
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sandboxie sandboxie sandbox-based isolation program developed sophos acquired invincea acquired earlier original author ronen tzur 32- 64-bit windows nt-based operating systems creates sandbox-like isolated operating environment applications run installed without permanently modifying local mapped drive isolated virtual environment allows controlled testing untrusted programs web surfing december 2013 invincea announced acquisition sandboxie original developer ronen tzur announced longer involved program february 2017 sophos announced acquisition invincea invincea posted assurance sandboxie website time sandboxie development support continue normal april 2019 official site shut preventing downloads installations purchases prompted creation temporary forum company domain may 2019 official site partially back purchase options regular forums still shut version 4.02 sandboxie full support 64-bit versions windows exception windows xp 64-bit never supported sandboxie released proprietary end-user license agreement eula home users may continue using sandboxie free without paying register however two functions remain disabled automatically running programs sandboxie simultaneous use multiple sandboxes 30 days sandboxie starts registration nagware message user dismiss 5-second delay sandboxie included brothersoft 2010 editors pick list gizmo freeware gave sandboxie rating 9 10 stars included editors choice list best free browser protection utility softonic given sandboxie rating 8 10 elena santos stating review sandboxie handy tool test untrustworthy software without putting system danger
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Computer security
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mitro mitro password manager individuals teams securely saved users logins allowed users log share access october 6 2015 mitro service shut successor mitro named passopolis password manager built upon mitro source code mitro founded 2012 vijay pandurangan evan jones adam hilss july 31 2014 mitro team announced would join twitter time released source code mitro github free software gpl mitro team announced shuttering mitro service following timeline mitro team explained reason shutting service cost administrative burden maintain service spare time money become much given could properly manage service people rely security needed stop running former customers encouraged move passopolis independent project uses open source mitro code use alternatives 1password dashlane lastpass october 5 2015 mitro officially terminated twitter mitro backed 1.2 million seed funding google ventures matrix partners mitro uses google keyczar server keyczar js implementation browser
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Computer security
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snort software snort free open source network intrusion detection system ids intrusion prevention system ips created 1998 martin roesch founder former cto sourcefire snort developed cisco purchased sourcefire 2013 2009 snort entered infoworld open source hall fame one greatest pieces open source software time snort open source network-based intrusion detection/prevention system ids/ips ability perform real-time traffic analysis packet logging internet protocol ip networks snort performs protocol analysis content searching matching program also used detect probes attacks including limited operating system fingerprinting attempts semantic url attacks buffer overflows server message block probes stealth port scans snort configured three main modes sniffer packet logger network intrusion detection sniffer mode program read network packets display console packet logger mode program log packets disk intrusion detection mode program monitor network traffic analyze rule set defined user program perform specific action based identified several third-party tools interfacing snort administration reporting performance log analysis
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Computer security
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unixware unixware unix operating system originally released univel jointly owned venture unix system laboratories usl novell taken novell via santa cruz operation sco went caldera systems caldera international sco group sold unxis xinuos unixware typically deployed server rather desktop binary distributions unixware available x86 architecture computers unixware primarily marketed server operating system svr4 effort merge sunos system v unix system laboratories usl formed univel partnership novell develop desktop version unix codenamed destiny destiny based unix system v release 4.2 kernel moolit toolkit used windowing system allowing user choose open look motif-like look feel run time order make system robust commodity desktop hardware veritas vxfs journaling file system used place ufs file system used svr4 networking support unixware included tcp/ip interoperability novell netware protocols ipx/spx former standard among unix users time development pc networking much commonly based netware destiny released 1992 unixware 1.0 intention unifying fragmented pc unix market behind single variant operating system system earlier reach corporate computing market microsoft windows nt observers period remarked unixware another flavor unix novell involvement marketing ploy significant influx technology os existed two editions personal edition included novell ipx networking tcp/ip advanced server edition tcp/ip server software personal edition limited two active users server edition included unlimited user license around 35,000 copies unixware 1.0 sold 1993 novell purchased usl merged usl univel new unix systems group 1994 novell released unixware 1.1 included tcp/ip personal advanced server editions motif 1.2 runtime libraries included cose compliance nuc netware unix client software included integration novell netware servers advanced merge application installed server personal editions allow running dos windows 3.1 applications novell later released bug-fix versions 1.1.1 1.1.2 1.1.3 finally 1.1.4 19 june 1995 unixware 2.0 based unix system v release 4.2mp kernel added support multiprocessing began shipping oems developers december 1994 consumer market march 1995 personal server editions supported two processor systems possibility buying extra processor upgrade licenses server edition supported multiprocessor systems included standard intel mp 1.1 smp machines corollary c-bus systems system supported netware odi network drivers effort increase number supported network interfaces new features release included posix threads library addition older ui threads library sco licensed unixware 1995 novell also announced project create supernos based netware 4.1 unixware 2.0 technologies future however never materialized instead netware 4.10 server linux offered caldera netware linux openlinux since 1998 novell open enterprise server finally came 2005 1995 santa cruz operation sco acquired unixware novell exact terms transaction disputed see sco vs novell courts subsequently determined novell retained ownership unix transfer made public sco announced would work towards merging unixware openserver svr3.2 based os first release unixware sco version 2.1 1996 release unixware 2.1 announced proposed unixware/openserver merger known project gemini available 1997 64-bit version unixware developed 1998 one controversial change adoption openserver like user licensing policy univel novell releases unixware allowed 2 users personal edition unlimited numbers users server edition unixware 2.1 server edition included license 5 users customers wanting users could buy 10 25 100 500 unlimited user license extensions sco released three updates unixware 2.1 unixware 2.1.1 released 1996 achieved unix 95 branding unixware 2.1.2 2.1.3 available 1998 largely bug fix releases 1998 compaq released package known integrity xc consisting single-system image cluster proliant servers version unixware 2.1 unixware nonstop clusters first results gemini project made available early 1998 unixware 7 sco named kernel version unix system v release 5 system largely based unixware 2.1 features driver compatibility openserver allowing use openserver network drivers system administration utilities openserver scoadmin replaced original unixware sysadm utility major new features unixware 7 included multi-path i/o large files file systems support large memory systems unixware 7 lacked xenix compatibility features ancestors licensing reasons avoid paying microsoft code included svr3.2 1999 sco released unixware 7.1 update increased number editions business 5-user department 25 user enterprise 50 user editions replaced earlier personal server editions webtop application tarantella inc. included 2000 sco released unixware 7.1.1 update simultaneously unixware nonstop clusters 7.1.1+ip single-system image cluster package released new package allowed commodity hardware used well proprietary compaq hardware supported earlier integrity xc product directly available sco 2 august 2000 santa cruz operation sco announced would sell server software services divisions well rights openserver unixware products caldera systems march 2001 caldera systems became caldera international cii sco purchase completed may 2001 remaining part santa cruz operation company tarantella division changed name tarantella inc. caldera international initial release unixware renamed openunix 8 release would unixware 7.1.2 caldera international renamed sco group august 2002 broadening product line include mobile products services later newly renamed sco group reverted previous unixware brand version release numbering releasing unixware 7.1.3 7.1.4 openunix releases made available openunix 8.1.2 ou812 never released sco group continued maintain unixware issues periodic maintenance updates support 2007 2011 sco group engaged series legal battles september 2007 sco group filed chapter 11 bankruptcy protection 11 april 2011 unxis bought sco group operating assets intellectual property rights approved bankruptcy court delaware sco group inc. renamed tsg group inc. sco operations inc. became tsg operations inc. august 2012 filed convert chapter 11 chapter 7 rights unixware well openserver acquired unxis 2011 june 2013 unxis renamed xinuos announced product availability sco unixware 7.1.4+ supporting physical virtual machines versions unixware included significant open source components including bind/x11/sendmail/dhcp/perl/tcl others later releases bundled numerous additional open source applications including apache samba mysql postgresql openssh mozilla software versions sco operating system distributions including unixware also extensive set open source packages available free download via sco skunkware site
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Operating systems
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version 6 unix sixth edition unix also called version 6 unix v6 first version unix operating system see wide release outside bell labs released may 1975 like direct predecessor targeted dec pdp-11 family minicomputers superseded version 7 unix 1978/1979 although v6 systems remained regular operation least 1985 corporation licensed version 5 unix educational institutions licensed version 6 also commercial users 20,000 remained widely used version 1980s enhanced v6 basis first ever commercially sold unix version interactive is/1 bell pwb/unix 1.0 also based v6 earlier unreleased versions based v4 v5 whitesmiths produced marketed binary-compatible v6 clone name idris code original v6 unix made available bsd license sco group see ancient unix systems since source code available license explicit enough forbid v6 taken teaching tool notably university california berkeley johns hopkins university university new south wales unsw uc berkeley distributed set add-on programs called first berkeley software distribution 1bsd later became full-fledged operating system distribution unsw professor john lions famous commentary unix 6th edition edited selection main parts kernel implemented digital pdp-11/40 main source kernel documentation many early unix developers due license restrictions later unix versions book mainly distributed samizdat photo-copying 1977 richard miller ross nealon working supervision professor juris reinfelds wollongong university completed port v6 unix interdata 7/32 thus proving portability unix new systems programming language c practice wollongong interdata unix level 6 also included utilities developed wollongong later releases features v7 notably c compiler wollongong unix first ever port platform pdp series computers proving portable operating systems indeed feasible c language write 1980 version licensed wollongong group palo alto published edition 7 around time bell labs port interdata 8/32 completed externally released goal port improve portability unix generally well produce portable version c compiler resulting portable c compiler pcc distributed v7 many later versions unix used produce unix/32v port vax third unix portability project completed princeton n.j. 1976–1977 unix kernel adapted run guest operating ibm vm/370 virtualization environment version became nucleus amdahl first internal unix offering see amdahl uts bell labs developed several variants v6 including stripped-down mini-unix low-end pdp-11 models lsi-unix lsx lsi-11 real-time operating system unix/rt merged v6 unix earlier mert hypervisor decided distribution bell labs number pre-v7 bug fixes would constitute support disallowed antitrust settlement tape patchset slipped lou katz usenix distributed university sydney released australian unix share accounting method ausam november 1979 v6 variant improved security process accounting eastern bloc clones v6 unix appeared local-built pdp-11 clones mnos later augmented partial compatibility bsd unix elektronika bk personal computer bkunix based lsx v6 used teaching mit 2002 2006 subsequently replaced x86 clone called xv6
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Operating systems
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norton confidential norton confidential program designed encrypt passwords online detect phishing sites
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Computer security
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session replay session replay ability replay visitor journey web site within mobile application web application replay include user view browser screen output user input keyboard mouse inputs logs network events console logs supposed help improve customer experience identify obstacles conversion processes websites however also used study web site usability customer behavior well handling customer service questions customer journey interactions replayed organizations even use capability analyse fraudulent behavior websites solutions augment session replay advanced analytics identify segments customers struggling use website means replay capability used much efficiently reduce need replay customer sessions unnecessarily generally two ways capture replay visitor sessions client side tag-free server side many tag-based solutions offer video-like replay visitors session replay analogous video accurately reproduction specific user experience mouse movements clicks taps scrolls underlying data session recordings captured tagging pages advanced tools able access dom directly play back interactions within dom including mutations high degree accuracy number tools provide similar functions advantage replay movie-like format full client experience also deal modern single-page applications disadvantage tracking script easily detected blocked ad blocker becomes normal 2017 615m devices active adblock solutions capture website traffic replay every visitor interaction every device including mobile users location sessions replayed step-by-step providing ability search locate analyse aspects visitors session including clicks form entry server-side solutions require hardware software installed premises advantage server-side recording solution ca n't blocked unfortunately wo n't able see video like replay client-side activities scrolling mouse movements deals badly modern single-page applications hybrid approach combines advantages without weaknesses hybrid approach ensures every session recorded important compliance server-side capturing enriched client-side tracking data mouse movements clicks scrolling key strokes user behavior driven customer experience insights works well modern single-page applications benefit movie-like replay additionally ensure 100 compliant capturing deployed either premises saas tools listed available software service saas solutions
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Web technology
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cross-platform support middleware cross-platform support middleware cpsm software abstraction layer guarantees existence correct implementation set services top set platforms abstraction method cpsm development method used compile concrete source code given platform without compromising abstract interfaces provided commonly used abstraction methods cpsm development conditional compilation directory separation sources first method consists embedding preprocessor instructions source code conditionally select source subtree compatible given platform second method takes advantage filesystem organization divide source code different folders one incompatible platform thus delegating selection problem build system distributions like msys cygwin may help build cross-platform code unix-like environment even microsoft windows distributions provide decent version gnu make direct build process cross-platform fashion
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Distributed computing architecture
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seamoby seamoby candidate access router discovery card experimental protocol outlined rfc 4065 rfc 4066 protocol designed speed hand ip devices wireless access routers protocol defines mechanism used access router automatically discover neighbor help mobile devices based trigger mobile devices scan neighbor access points report list newly found access point identifiers connected access router connected access router performs reverse look using ap id identify candidate access routers connected newfound access points connected access router updates neighbor list ip address capability newly found access routers neighbor list used inter-ar handover decision making similar idea currently used 3gpp son protocol aka anr discovering candidate access points however anr protocol extends rrc x2 protocols support card-like functionality l2 network
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Internet protocols
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ibm power instruction set architecture ibm power isa reduced instruction set computer risc instruction set architecture isa developed ibm name acronym performance optimization enhanced risc isa used base high end microprocessors ibm 1990s used many ibm servers minicomputers workstations supercomputers processors called power1 rios-1 rios.9 rsc rad6000 power2 power2 power2+ p2sc isa evolved powerpc instruction set architecture deprecated 1998 ibm introduced power3 processor mainly 32/64 bit powerpc processor included power isa backwards compatibility power isa abandoned ibm continues develop powerpc microprocessor cores use application-specific integrated circuit asic offerings many high volume applications embed powerpc cores 1974 ibm started project design objective creating large telephone-switching network potential capacity deal least 300 calls per second projected 20,000 machine instructions would required handle call maintaining real-time response processor performance 12 mips deemed necessary requirement extremely ambitious time realised much complexity contemporary cpus could dispensed since machine would need perform i/o branches add register-register move data registers memory would need special instructions perform heavy arithmetic simple design philosophy whereby step complex operation specified explicitly one machine instruction instructions required complete constant time would later come known risc 1975 telephone switch project canceled without prototype estimates simulations produced project first year however looked processor designed project could promising general-purpose processor work continued thomas j. watson research center building 801 801 project two years watson research center superscalar limits 801 design explored feasibility implementing design using multiple functional units improve performance similar done ibm system/360 model 91 cdc 6600 although model 91 based cisc design determine risc machine could maintain multiple instructions per cycle design changes need made 801 design allow multiple-execution-units increase performance cheetah separate branch fixed-point floating-point execution units many changes made 801 design allow multiple-execution-units cheetah originally planned manufactured using bipolar emitter-coupled logic ecl technology 1984 complementary metal–oxide–semiconductor cmos technology afforded increase level circuit integration improving transistor-logic performance 1985 research second-generation risc architecture started ibm thomas j. watson research center producing america architecture 1986 ibm austin started developing rs/6000 series based architecture february 1990 first computers ibm incorporate power instruction set called risc system/6000 rs/6000 rs/6000 computers divided two classes workstations servers hence introduced powerstation powerserver rs/6000 cpu 2 configurations called rios-1 rios.9 commonly power1 cpu rios-1 configuration total 10 discrete chips instruction cache chip fixed-point chip floating-point chip 4 data cache chips storage control chip input/output chips clock chip lower cost rios.9 configuration 8 discrete chips instruction cache chip fixed-point chip floating-point chip 2 data cache chips storage control chip input/output chip clock chip single-chip implementation rios rsc risc single chip developed lower-end rs/6000 first machines using rsc released 1992 ibm started power2 processor effort successor power1 two years creation 1991 apple/ibm/motorola alliance austin texas despite impacted diversion resources jump start apple/ibm/motorola effort power2 took five years start system shipment adding second fixed-point unit second floating point unit performance enhancements design power2 leadership performance announced november 1993 new instructions also added instruction set support rs/6000 rs/6000 sp2 product lines 1996 ibm design team implement single-chip version power2 p2sc power2 super chip outside apple/ibm/motorola alliance ibm advanced dense cmos-6s process p2sc combined separate power2 instruction cache fixed point floating point storage control data cache chips onto one huge die time introduction p2sc largest highest transistor count processor industry despite challenge size complexity advanced cmos process first tape-out version processor able shipped leadership floating point performance time announced p2sc processor used 1997 ibm deep blue chess playing supercomputer beat chess grandmaster garry kasparov twin sophisticated maf floating point units huge wide low latency memory interfaces p2sc primarily targeted engineering scientific applications p2sc eventually succeeded power3 included 64-bit smp capability full transition powerpc addition p2sc sophisticated twin maf floating point units power design descended directly 801 cpu widely considered first true risc processor design 801 used number applications inside ibm hardware time pc/rt released ibm started america project design powerful cpu market interested primarily fixing two problems 801 design floating point became focus america project ibm able use new algorithms developed early 1980s could support 64-bit double-precision multiplies divides single cycle fpu portion design separate instruction decoder integer parts allowing decoder send instructions fpu alu integer execution units time ibm complemented complex instruction decoder could fetching one instruction decoding another sending one alu fpu time resulting one first superscalar cpu designs use system used 32 32-bit integer registers another 32 64-bit floating point registers unit branch unit also included number private registers use including program counter another interesting feature architecture virtual address system maps addresses 52-bit space way applications share memory flat 32-bit space programs different blocks 32 bits appendix e book powerpc user instruction set architecture powerpc architecture book version 2.02 describes differences power power2 instruction set architectures version powerpc instruction set architecture implemented power5
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Computer architecture
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replicanet distributed computing distributed object systems designed allow software modules objects work together objects located different computers connected network interactive computer simulations computer games use object-oriented programming languages c++ maintain database entities player characters monsters tanks anything exist simulated world using object description language programmatically registering filter classes machine knows create update c++ class object object treated potential network shareable object machine allocates machine control c++ classes change variables call member functions normal object ready shared machines object published replicanet network session underlying replicanet software detects changes object automatically updates replicated classes machines connected network session changes made member variables c++ classes extrapolated replicanet using several pre-defined filters reduce amount network traffic transmitting changes object approach describing objects processed computers similar systems corba java remote method invocation distributed component object model 2011 game developer magazine announced replicanet 7.0 one networking finalists front line awards honors best networking middleware computer games industry game programming c++ start finish erik yuzwa http //gameprogrammingstarttofinish.wazooinc.com/ massively multiplayer game development 2 page 220 charles river media
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Distributed computing architecture
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edward snowden edward joseph snowden born june 21 1983 american whistle-blower copied leaked highly classified information national security agency nsa 2013 central intelligence agency cia employee subcontractor disclosures revealed numerous global surveillance programs many run nsa five eyes intelligence alliance cooperation telecommunication companies european governments prompted cultural discussion national security individual privacy 2013 snowden hired nsa contractor booz allen hamilton previous employment dell cia snowden says gradually became disillusioned programs involved tried raise ethical concerns internal channels ignored may 20 2013 snowden flew hong kong leaving job nsa facility hawaii early june revealed thousands classified nsa documents journalists glenn greenwald laura poitras ewen macaskill snowden came international attention stories based material appeared guardian washington post disclosures made publications including der spiegel new york times snowden 30th birthday june 21 2013 u.s. department justice unsealed charges snowden two counts violating espionage act 1917 theft government property following department state revoked passport two days later flew moscow sheremetyevo airport russian authorities noted u.s. passport cancelled restricted airport terminal one month russia later granted snowden right asylum initial visa residence one year repeated extensions permitted stay least 2020 early 2016 became president freedom press foundation san francisco-based organization states purpose protect journalists hacking government surveillance 2017 living undisclosed location moscow edward joseph snowden born june 21 1983 elizabeth city north carolina maternal grandfather edward j. barrett rear admiral u.s. coast guard became senior official fbi pentagon 2001 september 11 attacks snowden father lonnie also officer coast guard mother elizabeth clerk u.s. district court district maryland older sister jessica lawyer federal judicial center washington d.c. edward snowden said expected work federal government rest family parents divorced 2001 father remarried snowden scored 145 two separate iq tests early 1990s still grade school snowden moved family area fort meade maryland mononucleosis caused miss high school almost nine months rather returning school passed ged test took classes anne arundel community college although snowden undergraduate college degree worked online toward master degree university liverpool england 2011 interested japanese popular culture studied japanese language worked anime company resident office u.s also said basic understanding mandarin chinese deeply interested martial arts age 20 listed buddhism religion military recruitment form noting choice agnostic strangely absent snowden said 2008 presidential election voted third-party candidate though believed obama promises following election believed president barack obama continuing policies espoused george w. bush accounts published june 2013 interviewers noted snowden laptop displayed stickers supporting internet freedom organizations including electronic frontier foundation eff tor project week publication leaks began ars technica confirmed snowden active participant site online forum 2001 may 2012 discussing variety topics pseudonym thetruehooha january 2009 entry thetruehooha exhibited strong support u.s. security state apparatus said leakers classified information shot balls however snowden disliked obama cia director appointment leon panetta saying obama named fucking politician run cia snowden also offended possible ban assault weapons writing lunatic gun-toting nra compatriots would steps congress c-span feed finished snowden disliked obama economic policies social security favored ron paul call return gold standard 2014 snowden supported basic income feeling duty fight iraq war help free oppressed people snowden enlisted united states army reserve may 7 2004 became special forces candidate 18x enlistment option complete training breaking legs training accident discharged september 28 2004 snowden employed less year 2005 security guard university maryland center advanced study language research center sponsored national security agency nsa according university classified facility though heavily guarded june 2014 snowden told wired job security guard required high-level security clearance passed polygraph exam underwent stringent background check attending 2006 job-fair focused intelligence agencies snowden accepted offer position cia agency assigned global communications division cia headquarters langley virginia may 2006 snowden wrote ars technica trouble getting work computer wizard distinguishing junior employee top computer-team snowden sent cia secret school technology specialists lived hotel six months studying training full-time march 2007 cia stationed snowden diplomatic cover geneva switzerland responsible maintaining computer-network security assigned u.s permanent mission united nations diplomatic mission representing u.s. interests un international organizations snowden received diplomatic passport four-bedroom apartment near lake geneva according greenwald snowden considered top technical cybersecurity expert country hand-picked cia support president 2008 nato summit romania snowden described cia experience geneva formative stating cia deliberately got swiss banker drunk encouraged drive home snowden said latter arrested cia operative offered help exchange banker becoming informant ueli maurer president swiss confederation year 2013 june year publicly disputed snowden claims would mean cia successfully bribed geneva police judiciary due respect ca n't imagine said maurer february 2009 snowden resigned cia 2009 snowden began work contractee dell manages computer systems multiple government agencies assigned nsa facility yokota air base near tokyo snowden instructed top officials military officers defend networks chinese hackers four years dell rose supervising nsa computer system upgrades working résumé termed cyberstrategist expert cyber counterintelligence several u.s. locations 2011 returned maryland spent year lead technologist dell cia account capacity consulted chiefs cia technical branches including agency chief information officer chief technology officer u.s. officials sources familiar investigation said snowden began downloading documents describing government electronic spying programs working dell april 2012 investigators estimated 50,000 200,000 documents snowden gave greenwald poitras copied snowden working dell march 2012 dell reassigned snowden hawaii lead technologist nsa information-sharing office time departure u.s. may 2013 employed 15 months inside nsa hawaii regional operations center focuses electronic monitoring china north korea last three consulting firm booz allen hamilton intelligence officials described position system administrator snowden said infrastructure analyst meant job look new ways break internet telephone traffic around world march 15 2013—three days later called breaking point seeing director national intelligence james clapper directly lie oath congress —snowden quit job dell although said career high annual salary 200,000 snowden said took pay cut work booz allen sought employment order gather data release details nsa worldwide surveillance activity anonymous source told reuters hawaii snowden may persuaded 20–25 co-workers give logins credentials telling needed job nsa sent memo congress saying snowden tricked fellow employee sharing personal public key infrastructure certificate gain greater access nsa computer system snowden disputed memo saying january 2014 never stole passwords trick army co-workers booz allen terminated snowden employment june 10 2013 one month left country former nsa co-worker said although nsa full smart people snowden genius among geniuses created widely implemented backup system nsa often pointed security flaws agency former colleague said snowden given full administrator privileges virtually unlimited access nsa data snowden offered position nsa elite team hackers tailored access operations turned join booz allen anonymous source later said booz allen hiring screeners found possible discrepancies snowden resume still decided hire snowden résumé stated attended computer-related classes johns hopkins university spokeswoman johns hopkins said university find records show snowden attended university suggested may instead attended advanced career technologies private for-profit organization operated computer career institute johns hopkins university university maryland university college acknowledged snowden attended summer session um campus asia snowden résumé stated estimated would receive university liverpool computer security master degree 2013 university said snowden registered online master degree program computer security 2011 inactive student completed program snowden said told multiple employees two supervisors concerns nsa disputes claim snowden elaborated january 2014 saying made tremendous efforts report programs co-workers supervisors anyone proper clearance would listen reactions told scale constitutional violations ranged deeply concerned appalled one willing risk jobs families possibly even freedom go thomas andrews drake march 2014 testimony european parliament snowden wrote revealing classified information reported clearly problematic programs ten officials said nothing response may 2014 interview snowden told nbc news bringing concerns legality nsa spying programs officials told stay silent matter asserted nsa copies emails sent office general counsel oversight compliance personnel broaching concerns nsa interpretations legal authorities raised complaints officially writing email supervisors colleagues one office may 2014 u.s. officials released single email snowden written april 2013 inquiring legal authorities said found evidence snowden expressed concerns someone oversight position june 2014 nsa said able find records snowden raising internal complaints agency operations month snowden explained produced communiqués question ongoing nature dispute disclosing first time working nsa regard records 're going back forth n't want reveal everything come may 2014 interview nbc news snowden accused u.s. government trying use one position career distract totality experience downplaying low level analyst words trained spy traditional sense word lived worked undercover overseas—pretending work job 'm not—and even assigned name mine said 'd worked nsa undercover overseas dia developed sources methods keep information people secure hostile dangerous environments around world say 'm low-level systems administrator n't know 'm talking 'd say somewhat misleading june interview globo tv snowden reiterated actually functioning senior level july interview guardian snowden explained nsa career began move merely overseeing systems actively directing use many people ’ understand actually analyst designated individuals groups targeting snowden subsequently told wired dell 2011 would sit cio cia cto cia chiefs technical branches would tell hardest technology problems job come way fix time nsa analyst directing work others snowden recalled moment colleagues began severe ethical doubts snowden said 18 22-year-old analysts suddenly thrust position extraordinary responsibility access private records course daily work stumble across something completely unrelated sort necessary sense—for example intimate nude photo someone sexually compromising situation 're extremely attractive turn around chair show co-worker ... sooner later person whole life seen people snowden observed behavior happened routinely every two months never reported considered one fringe benefits work exact size snowden disclosure unknown australian officials estimated 15,000 australian intelligence files british officials estimate least 58,000 british intelligence files nsa director keith alexander initially estimated snowden copied anywhere 50,000 200,000 nsa documents later estimates provided u.s. officials order 1.7 million number originally came department defense talking points july 2014 washington post reported cache previously provided snowden domestic nsa operations consisting roughly 160,000 intercepted e-mail instant-message conversations hundreds pages long 7,900 documents taken 11,000 online accounts u.s. defense intelligence agency report declassified june 2015 said snowden took 900,000 department defense files downloaded nsa march 2014 army general martin dempsey chairman joint chiefs staff told house armed services committee vast majority documents snowden ... exfiltrated highest levels security ... nothing exposing government oversight domestic activities vast majority related military capabilities operations tactics techniques procedures asked may 2014 interview quantify number documents snowden stole retired nsa director keith alexander said accurate way counting took snowden may downloaded million documents according snowden indiscriminately turn documents journalists stating carefully evaluated every single document disclosed ensure legitimately public interest sorts documents would made big impact n't turn screen everything releasing journalists ... time go information would like make available journalists country despite measures improper redaction document new york times resulted exposure intelligence activity al-qaeda june 2014 nsa recently installed director u.s. navy admiral michael s. rogers said terrorist groups altered communications avoid surveillance techniques revealed snowden damage done significant enough conclude sky falling nevertheless february 2015 rogers said snowden disclosures material impact nsa detection evaluation terrorist activities worldwide 14 june 2015 uk sunday times reported russian chinese intelligence services decrypted 1 million classified files snowden cache forcing uk mi6 intelligence agency move agents live operations hostile countries sir david omand former director uk gchq intelligence gathering agency described huge strategic setback harming britain america nato allies sunday times said clear whether russia china stole snowden data whether snowden voluntarily handed remain liberty hong kong moscow april 2015 henry jackson society british neoconservative think tank published report claiming snowden intelligence leaks negatively impacted britain ability fight terrorism organized crime gus hosein executive director privacy international criticized report opinion presuming public became concerned privacy snowden disclosures snowden decision leak nsa documents developed gradually following march 2007 posting technician geneva cia station snowden first made contact glenn greenwald journalist working guardian december 1 2012 contacted greenwald anonymously cincinnatus said sensitive documents would like share greenwald found measures source asked take secure communications encrypting email annoying employ snowden contacted documentary filmmaker laura poitras january 2013 according poitras snowden chose contact seeing new york times article nsa whistleblower william binney originally attracted snowden greenwald poitras salon article written greenwald detailing poitras controversial films made target government greenwald began working snowden either february april 2013 poitras asked greenwald meet new york city point snowden began providing documents barton gellman writing washington post says first direct contact may 16 2013 according gellman snowden approached greenwald post declined guarantee publication within 72 hours 41 powerpoint slides snowden leaked exposing prism electronic data mining program publish online encrypted code allowing snowden later prove source snowden communicated using encrypted email going codename verax asked quoted length fear identification stylometry according gellman prior first meeting person snowden wrote understand made suffer actions return information public marks end snowden also told gellman articles published journalists working would also mortal risk united states intelligence community think single point failure could stop disclosure make sole owner information may 2013 snowden permitted temporary leave position nsa hawaii pretext receiving treatment epilepsy mid-may snowden gave electronic interview poitras jacob appelbaum published weeks later der spiegel disclosing copied documents snowden promised nothing would stop subsequent disclosures june 2013 said say right us government going able cover jailing murdering truth coming stopped may 20 2013 snowden flew hong kong staying initial articles based leaked documents published beginning guardian june 5 greenwald later said snowden disclosed 9,000 10,000 documents within months documents obtained published media outlets worldwide notably guardian britain der spiegel germany washington post new york times u.s. globo brazil le monde france similar outlets sweden canada italy netherlands norway spain australia 2014 nbc broke first story based leaked documents february 2014 reporting based snowden leaks journalists glenn greenwald laura poitras barton gellman guardian′ ewen macaskill honored co-recipients 2013 george polk award dedicated snowden nsa reporting journalists also earned guardian washington post 2014 pulitzer prize public service exposing widespread surveillance helping spark huge public debate extent government spying guardian chief editor alan rusbridger credited snowden performed public service ongoing publication leaked documents revealed previously unknown details global surveillance apparatus run united states nsa close cooperation three four five eyes partners australia asd uk gchq canada csec june 5 2013 media reports documenting existence functions classified surveillance programs scope began continued throughout entire year first program revealed prism allows court-approved direct access americans google yahoo accounts reported washington post guardian published one hour apart barton gellman washington post first journalist report snowden documents said u.s. government urged specify name companies involved gellman decided name would make real americans reports also revealed details tempora british black-ops surveillance program run nsa british partner gchq initial reports included details nsa call database boundless informant secret court order requiring verizon hand nsa millions americans phone records daily surveillance french citizens phone internet records high-profile individuals world business politics xkeyscore analytical tool allows collection almost anything done internet described guardian program shed light one snowden controversial statements sitting desk could wiretap anyone accountant federal judge even president personal email nsa top-secret black budget obtained snowden washington post exposed successes failures 16 spy agencies comprising u.s. intelligence community revealed nsa paying u.s. private tech companies clandestine access communications networks agencies allotted 52 billion 2013 fiscal year revealed nsa harvesting millions email instant messaging contact lists searching email content tracking mapping location cell phones undermining attempts encryption via bullrun agency using cookies piggyback tools used internet advertisers pinpoint targets government hacking bolster surveillance nsa shown secretly accessing yahoo google data centers collect information hundreds millions account holders worldwide tapping undersea cables using muscular surveillance program nsa cia gchq spied users second life xbox live world warcraft attempted recruit would-be informants sites according documents revealed december 2013 leaked documents showed nsa agents also spied love interests practice nsa employees termed loveint nsa shown tracking online sexual activity people termed radicalizers order discredit following revelation black pearl program targeting private networks nsa accused extending beyond primary mission national security agency intelligence-gathering operations targeted among others oil giant petrobras brazil largest company nsa gchq also shown surveilling charities including unicef médecins du monde well allies european commissioner joaquín almunia israeli prime minister october 2013 glenn greenwald said shocking significant stories ones still working yet publish november guardian editor-in-chief alan rusbridger said one percent documents published december australia minister defence david johnston said government assumed worst yet come october 2013 snowden disclosures created tensions u.s. close allies revealed u.s. spied brazil france mexico britain china germany spain well 35 world leaders notably german chancellor angela merkel said spying among friends unacceptable compared nsa stasi leaked documents published der spiegel 2014 appeared show nsa targeted 122 high-ranking leaders nsa mission statement titled sigint strategy 2012-2016 affirmed nsa plans continued expansion surveillance activities stated goal dramatically increase mastery global network acquire adversaries data anyone anytime anywhere leaked slides revealed greenwald book place hide released may 2014 showed nsa stated objective collect process exploit partner sniff know snowden said january 2014 interview german television nsa limit data collection national security issues accusing agency conducting industrial espionage using example german company siemens said information siemens beneficial us national interests—even n't anything national security—then 'll take information nevertheless wake snowden revelations response inquiry left party germany domestic security agency bundesamt für verfassungsschutz bfv investigated found concrete evidence u.s. conducted economic industrial espionage germany february 2014 testimony european union snowden said remaining undisclosed programs leave public interest determinations may safely disclosed responsible journalists coordination government stakeholders march 2014 documents disclosed glenn greenwald writing intercept showed nsa cooperation gchq plans infect millions computers malware using program called turbine revelations included information quantumhand program nsa set fake facebook server intercept connections according report washington post july 2014 relying information furnished snowden 90 placed surveillance u.s. ordinary americans intended targets newspaper said examined documents including emails message texts online accounts support claim august 2014 interview snowden first time disclosed cyberwarfare program works codenamed monstermind would automate detection foreign cyberattack began automatically fire back attacks spoofed said snowden could someone sitting china example making appear one attacks originating russia end shooting back russian hospital happens next snowden first contemplated leaking confidential documents around 2008 held back partly believed newly elected barack obama might introduce reforms disclosures identity made public guardian request june 9 2013 want live world everything say recorded said sole motive inform public done name done snowden said wanted embolden others step forward demonstrating win also said system reporting problems work report wrongdoing responsible cited lack whistleblower protection government contractors use 1917 espionage act prosecute leakers belief used internal mechanisms sound alarm revelations would buried forever december 2013 upon learning u.s. federal judge ruled collection u.s. phone metadata conducted nsa likely unconstitutional snowden said acted belief nsa mass surveillance programs would withstand constitutional challenge american public deserved chance see issues determined open courts ... today secret program authorized secret court exposed light day found violate americans rights january 2014 snowden said breaking point seeing director national intelligence james clapper directly lie oath congress referred testimony march 12 2013—three months snowden first sought share thousands nsa documents greenwald nine months nsa says snowden made first illegal downloads summer 2012—in clapper denied u.s. senate select committee intelligence nsa wittingly collects data millions americans snowden said saving intelligence community believes lie public legislators need able trust regulate actions seeing really meant going back beyond creeping realization one else going public right know programs march 2014 snowden said reported policy legal issues related spying programs ten officials contractor legal avenue pursue whistleblowing may 2013 snowden took leave absence telling supervisors returning mainland epilepsy treatment instead left hawaii hong kong arrived may 20 snowden told guardian reporters june room mira hotel since arrival city rarely going june 10 correspondent ewen macaskill said snowden left hotel briefly three times since may 20 snowden vowed challenge extradition attempt u.s. government engaged hong kong-based canadian human rights lawyer robert tibbo legal adviser snowden told south china morning post planned remain hong kong long government would permit snowden also told post united states government committed tremendous number crimes hong kong prc well going identify chinese internet protocol addresses nsa monitored stating nsa collected text-message data hong kong residents glenn greenwald said snowden motivated need ingratiate people hong kong china leaving mira hotel snowden stayed cramped apartment refugees seeking asylum hong kong arrangement set tibbo hide authorities russian newspaper kommersant nevertheless reported snowden living russian consulate shortly departure hong kong moscow ben wizner lawyer american civil liberties union aclu legal adviser snowden said january 2014 every news organization world trying confirm story n't able false ref name= mayer/new yorker /ref likewise rejecting kommersant story anatoly kucherena became snowden lawyer july 2013 snowden asked help seeking temporary asylum russia kucherena said snowden communicate russian diplomats hong kong early september 2013 however russian president vladimir putin said days boarding plane moscow snowden met hong kong russian diplomatic representatives june 22 18 days publication snowden nsa documents began officials revoked u.s. passport june 23 snowden boarded commercial aeroflot flight su213 moscow accompanied sarah harrison wikileaks hong kong authorities said snowden detained u.s. request fully complied hong kong law legal basis prevent snowden leaving june 24 u.s. state department spokesman rejected explanation technical noncompliance accusing hong kong government deliberately releasing fugitive despite valid arrest warrant sufficient time prohibit travel day julian assange said wikileaks paid snowden lodging hong kong flight october 2013 snowden said flying moscow gave classified documents obtained journalists met hong kong kept copies january 2014 told german tv interviewer gave information american journalists reporting american issues first american tv interview may 2014 snowden said protected russian leverage destroying material holding landing moscow june 23 2013 snowden landed moscow sheremetyevo airport wikileaks said circuitous safe route asylum ecuador snowden seat reserved continue cuba board onward flight saying january 2014 interview intended transit russia stopped en route asserted planeload reporters documented seat supposed ticketed havana u.s. cancelled passport said u.s. wanted stay moscow could say 'he russian spy greenwald account differed point snowden already ticketed according greenwald snowden passport valid departed hong kong revoked hours transit moscow preventing obtaining ticket leave russia greenwald said snowden thus forced stay moscow seek asylum according one russian report snowden planned fly moscow havana latin america however cuba told moscow would allow aeroflot plane carrying snowden land russian newspaper kommersant reported cuba change heart receiving pressure u.s. officials leaving stuck transit zone last minute havana told officials moscow allow flight washington post contrasted version called widespread speculation russia never intended let snowden proceed fidel castro called claims cuba would blocked snowden entry lie libel describing snowden arrival moscow surprise likening unwanted christmas gift russian president putin said snowden remained transit area sheremetyevo airport committed crime russia free leave putin denied russia intelligence agencies worked working snowden following snowden arrival moscow white house expressed disappointment hong kong decision allow leave anonymous u.s. official authorized discuss matter told ap snowden passport revoked left hong kong senior official country airline could order subordinates overlook withdrawn passport u.s. secretary state john kerry said snowden passport cancelled within two hours charges snowden made public friday june 21 july 1 statement snowden said although convicted nothing u.s. government unilaterally revoked passport leaving stateless person without judicial order administration seeks stop exercising basic right right belongs everybody right seek asylum four countries offered snowden permanent asylum ecuador nicaragua bolivia venezuela direct flights moscow venezuela bolivia nicaragua existed however u.s. pressured countries along route hand snowden said july 2013 decided bid asylum russia felt safe way reach latin america snowden said remained russia talking possibilities asylum latin america united states forced bolivian president plane citing morales plane incident issue said governments western european north american states demonstrated willingness act outside law behavior persists today unlawful threat makes impossible travel latin america enjoy asylum granted accordance shared rights said would travel russia interference u.s. government four months snowden received asylum russia julian assange commented venezuela ecuador could protect short term long term could change government russia safe well-regarded likely change advice snowden would physically safest russia according snowden cia powerful presence latin america governments security services relatively much less capable say russia ... could basically snatched ... october 2014 interview nation magazine snowden reiterated originally intended travel latin america lot people still unaware never intended end russia according snowden u.s. government waited departed hong kong cancel passport order trap russia snowden added really wanted capture would 've allowed travel latin america cia operate impunity want chose keep russia july 1 2013 president evo morales bolivia attending conference russia suggested interview russia today would consider request snowden asylum following day morales plane en route bolivia rerouted austria landed france spain italy denied access airspace plane parked vienna spanish ambassador austria arrived two embassy personnel asked search plane denied permission morales u.s. officials raised suspicions snowden may board morales blamed u.s. putting pressure european countries said grounding plane violation international law april 2015 bolivia ambassador russia maría luisa ramos urzagaste accused julian assange inadvertently putting morales life risk intentionally providing u.s. false rumors snowden morales plane assange responded n't expecting outcome result caused united states intervention regret happened snowden applied political asylum 21 countries statement attributed contended u.s. administration specifically vice president joe biden pressured governments refuse asylum petitions biden telephoned president rafael correa days prior snowden remarks asking ecuadorian leader grant snowden asylum ecuador initially offered snowden temporary travel document later withdrew correa later called offer mistake july 1 statement published wikileaks snowden accused u.s. government using citizenship weapon using described old bad tools political aggression citing obama promise allow wheeling dealing case snowden commented kind deception world leader justice neither extralegal penalty exile several days later wikileaks announced snowden applied asylum six additional countries declined name alleging attempted u.s. interference evaluating law snowden situation french interior ministry rejected request asylum poland refused process application conform legal procedure brazil foreign ministry said government planned response snowden asylum request germany india rejected snowden application outright austria ecuador finland norway italy netherlands spain said must territory apply november 2014 germany announced snowden renewed previously denied request considered asylum glenn greenwald later reported sigmar gabriel vice-chancellor germany told u.s. government threatened stop sharing intelligence germany offered snowden asylum arranged travel putin said july 1 2013 snowden wanted granted asylum russia would required stop work aimed harming american partners spokesman putin subsequently said snowden withdrawn asylum application upon learning conditions july 12 meeting sheremetyevo airport representatives human rights organizations lawyers organized part russian government snowden said accepting offers asylum already received would receive added venezuela grant asylum formalized asylee status removing basis state interference right asylum also said would request asylum russia resolved travel problems russian federal migration service officials confirmed july 16 snowden submitted application temporary asylum july 24 kucherena said client wanted find work russia travel create life already begun learning russian amid media reports early july 2013 attributed u.s. administration sources obama one-on-one meeting putin ahead g20 meeting st petersburg scheduled september doubt due snowden protracted sojourn russia top u.s. officials repeatedly made clear moscow snowden immediately returned united states face charges unauthorized leaking classified information russian lawyer said snowden needed asylum faced persecution u.s. government feared could subjected torture capital punishment letter russian minister justice aleksandr konovalov dated july 23 u.s. attorney general eric holder repudiated snowden claim refugee status offered limited validity passport good direct return u.s asserted snowden would subject torture death penalty would receive trial civilian court proper legal counsel day russian president spokesman reiterated government would hand snowden noting putin personally involved matter handled talks fbi russia fsb june 14 2013 united states federal prosecutors filed criminal complaint snowden charging theft government property two counts violating espionage act 1917 unauthorized communication national defense information willful communication classified communications intelligence information unauthorized person three charges carries maximum possible prison term ten years charge initially secret unsealed week later snowden asked january 2014 interview returning u.s. face charges court obama suggested days prior snowden explained rejected request n't say crimes charged crimes n't allow make case n't allow defend open court public convince jury benefit ... would say illustrative president would choose say someone face music knows music show trial snowden legal representative jesselyn radack wrote espionage act effectively hinders person defending jury open court said arcane world war law never meant prosecute whistleblowers rather spies betrayed trust selling secrets enemies profit non-profit betrayals considered june 23 2013 snowden landed moscow sheremetyevo airport aboard commercial aeroflot flight hong kong august 1 39 days transit section left airport granted temporary asylum russia one year year later temporary asylum expired snowden received three-year residency permit allowing travel freely within russia go abroad three months granted permanent political asylum january 2017 spokesperson russian foreign ministry wrote facebook snowden asylum due expire 2017 extended couple years snowden lawyer anatoly kucherena said extension valid 2020 subject controversy snowden variously called hero whistleblower dissident patriot traitor pentagon papers leaker daniel ellsberg called snowden release nsa material significant leak u.s. history numerous high-ranking current former u.s. government officials reacted publicly snowden disclosures u.s. snowden actions precipitated intense debate privacy warrantless domestic surveillance president obama initially dismissive snowden saying 'm going scrambling jets get 29-year-old hacker august 2013 obama rejected suggestion snowden patriot november said benefit debate generated worth damage done another way june 2013 u.s senator bernie sanders vermont wrote blog love hate owe snowden thanks forcing upon nation important debate debate n't gnawing questions actions raised shadows snowden said december 2013 inspired global debate ignited leaks nsa culture indiscriminate global espionage ... collapsing end 2013 however washington post noted public debate offshoots produced meaningful change policy status quo continuing 2016 axe files podcast former u.s. attorney general eric holder said snowden performed public service raising debate engaged changes made holder nevertheless said snowden actions inappropriate illegal september 2016 bipartisan u.s. house permanent select committee intelligence completed review snowden disclosures said federal government would spend millions dollars responding fallout snowden disclosures report also said public narrative popularized snowden allies rife falsehoods exaggerations crucial omissions report denounced washington post reporter barton gellman called aggressively dishonest contemptuous fact august 2013 president obama said called review u.s. surveillance activities snowden begun revealing details nsa operations announced directing dni james clapper establish review group intelligence communications technologies december task force issued 46 recommendations adopted would subject nsa additional scrutiny courts congress president would strip nsa authority infiltrate american computer systems using backdoors hardware software panel member geoffrey r. stone said evidence bulk collection phone data stopped terror attacks june 6 2013 wake snowden leaks conservative public interest lawyer judicial watch founder larry klayman filed lawsuit claiming federal government unlawfully collected metadata telephone calls harassing klayman v. obama judge richard j. leon referred nsa almost-orwellian technology ruled bulk telephone metadata program probably unconstitutional snowden later described judge leon decision vindication june 11 aclu filed lawsuit james clapper director national intelligence alleging nsa phone records program unconstitutional december 2013 ten days judge leon ruling judge william h. pauley iii came opposite conclusion aclu v. clapper although acknowledging privacy concerns trivial pauley found potential benefits surveillance outweigh considerations ruled nsa collection phone data legal gary schmitt former staff director senate select committee intelligence wrote two decisions generated public confusion constitutionality nsa data collection program—a kind judicial 'he-said she-said standoff may 7 2015 case aclu v. clapper united states court appeals second circuit said section 215 patriot act authorize nsa collect americans calling records bulk exposed snowden 2013 decision voided u.s. district judge william pauley december 2013 finding nsa program lawful remanded case review appeals court rule constitutionality bulk surveillance declined enjoin program noting pending expiration relevant parts patriot act circuit judge gerard e. lynch wrote given national security interests stake prudent give congress opportunity debate decide matter june 2 2015 u.s. senate passed president obama signed usa freedom act restored modified form several provisions patriot act expired day first time imposing limits bulk collection telecommunication data u.s. citizens american intelligence agencies new restrictions widely seen stemming snowden revelations hans-georg maaßen head federal office protection constitution germany domestic security agency said snowden could working russian government snowden rejected insinuation crediting snowden leaks united nations general assembly unanimously adopted resolution 68/167 december 2013 non-binding resolution denounced unwarranted digital surveillance included symbolic declaration right individuals online privacy support snowden came latin american leaders including argentinian president cristina fernández de kirchner brazilian president dilma rousseff ecuadorian president rafael correa bolivian president evo morales venezuelan president nicolás maduro nicaraguan president daniel ortega official report published october 2015 united nations special rapporteur promotion protection right freedom speech professor david kaye criticized u.s. government harsh treatment bringing criminal charges whistleblowers including edward snowden report found snowden revelations important people everywhere made deep lasting impact law policy politics european parliament invited snowden make pre-recorded video appearance aid nsa investigation snowden gave written testimony said seeking asylum eu told european parliamentarians u.s. would allow eu partners make offer told parliament nsa working security agencies eu states get access much data eu citizens possible nsa foreign affairs division claimed lobbies eu countries change laws allowing everyone country spied legally july 2014 navi pillay un high commissioner human rights told news conference geneva u.s. abandon efforts prosecute snowden since leaks public interest surveys conducted news outlets professional polling organizations found american public opinion divided snowden disclosures polled canada europe supportive snowden respondents u.s. although americans grown supportive snowden disclosure global surveillance disclosures snowden honored publications organizations based europe united states voted guardian person year 2013 garnering four times number votes candidate march 2014 snowden spoke south southwest sxsw interactive technology conference austin texas front 3,500 attendees participated teleconference carried multiple routers running google hangouts platform on-stage moderators christopher soghoian snowden legal counsel wizner aclu snowden said nsa setting fire future internet sxsw audience firefighters attendees could use twitter send questions snowden answered one saying information gathered corporations much less dangerous gathered government agency governments power deprive rights representative mike pompeo r-ks house intelligence committee later director cia tried unsuccessfully get sxsw management cancel snowden appearance instead sxsw director hugh forrest said nsa welcome respond snowden 2015 conference later month snowden appeared teleconference ted conference vancouver british columbia represented stage robot video screen video camera microphones speakers snowden conversed ted curator chris anderson told attendees online businesses act quickly encrypt websites described nsa prism program u.s. government using businesses collect data nsa intentionally misleads corporate partners using example bullrun decryption program create backdoor access snowden said would gladly return u.s. given immunity prosecution concerned alerting public abuses government authority anderson invited internet pioneer tim berners-lee stage converse snowden said would support berners-lee concept internet magna carta encode values structure internet september 15 2014 snowden appeared via remote video link along julian assange kim dotcom moment truth town hall meeting held auckland made similar video link appearance february 2 2015 along greenwald keynote speaker world affairs conference upper canada college toronto march 2015 speaking fifdh international human rights film festival made public appeal switzerland grant asylum saying would like return live geneva worked undercover central intelligence agency november 10 2015 snowden appeared newseum via remote video link pen american center secret sources whistleblowers national security free expression event 2015 snowden earned 200,000 digital speaking engagements u.s. march 19 2016 snowden delivered opening keynote address libreplanet conference meeting international free software activists developers presented free software foundation conference held massachusetts institute technology first time snowden spoke via teleconference using full free software stack end-to-end july 21 2016 snowden hardware hacker bunnie huang talk mit media lab forbidden research event published research smartphone case so-called introspection engine would monitor signals received sent phone provide alert user phone transmitting receiving information n't example turned airplane mode feature described snowden useful journalists activists operating hostile governments would otherwise track activities phones july 2013 media critic jay rosen defined snowden effect direct indirect gains public knowledge cascade events reporting followed edward snowden leaks classified information surveillance state u.s. december 2013 nation wrote snowden sparked overdue debate national security individual privacy forbes effect seen nearly united u.s. congress opposition massive post-9/11 domestic intelligence gathering system spring 2014 global attitudes survey pew research center found snowden disclosures tarnished image united states especially europe latin america november 2 2018 snowden provided court declaration jewel v. national security agency snowden impact public figure felt cinema advertising video games literature music statuary social 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Computer security
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windows windows millennium edition windows marketed pronunciation pronoun codenamed millennium graphical operating system developed microsoft part windows 9x family operating systems successor windows 98 released manufacturing june 19 2000 general availability september 14 2000 windows last operating system released windows 9x series targeted specifically home pc users included internet explorer 5.5 windows media player 7 new windows movie maker software provided basic video editing designed easy use home users microsoft also updated graphical user interface shell features windows explorer first introduced windows 2000 released business-oriented operating system seven months earlier windows could upgraded internet explorer 6 sp1 sp2 sv1 internet explorer 7 outlook express 6 sp1 windows media player 9 series microsoft .net framework including version 2.0 supported however versions 2.0 sp1 3.x greater office xp last version microsoft office compatible windows windows continuation windows 9x model still dos-based like predecessors restricted access real mode ms-dos order decrease system boot time october 2001 windows xp released became windows successor popularizing features introducing visual themes including reliable windows nt kernel 1998 microsoft stated would version windows 9x windows 98 may 1999 however microsoft released windows 98 second edition announced new version windows 9x later revealed codenamed millennium 2000 released windows millennium edition windows least three beta versions windows available development phase september 24 1999 microsoft announced windows millennium beta 1 released windows millennium beta 2 released november 24 1999 added couple new features system file protection game options control panel several interim builds released beta 1 2 added features automatic updates personalized menus beta 3 released april 11 2000 version marked first appearance final version startup shutdown sounds derived windows 2000 previous betas used windows 98 startup shutdown sounds final version boot screen first featured pre-beta 3 build 2470 general availability date windows millennium edition september 14 2000 launch time microsoft announced time-limited promotion september 2000 – january 2001 entitled windows 95 windows 98 users upgrade windows 59.95 instead regular retail upgrade price 109 shortly windows released manufacturing june 19 2000 microsoft launched campaign-initiative promote windows u.s. dubbed meet tour national partnered promotional program featured windows oems partners interactive multimedia attraction 25 cities across u.s launched september 14 2000 compared releases windows windows short shelf-life year microsoft aimed make first consumer windows os based nt kernel however happen windows rushed market neptune project canceled windows along windows 2000 eventually succeded nt-based windows xp launched august 24 2001 windows featured shell enhancements inherited windows 2000 personalized menus customizable windows explorer toolbars auto-complete windows explorer address bar run box windows 2000 advanced file type association features displaying comments shortcuts tooltips extensible columns details view icolumnprovider interface icon overlays integrated search pane windows explorer sort name function menus places bar common dialogs open save cascading start menu special folders plus 95 plus 98 themes updated graphics notification area windows later supported 16-bit high color icons multimedia control panel also updated windows 98 se taskbar start menu options allowed disabling drag drop feature could prevent moving resizing taskbar easier new users windows restricted support real mode ms-dos result codice_5 windows disregards codice_1 codice_21 codice_22 directly executes codice_23 default configuration system would neither boot ms-dos command prompt exit dos windows real mode drivers codice_24 could loaded older applications require real mode could run microsoft argued change improved speed reliability boot process windows codice_1 codice_2 files used set global environment variables two files present scanned settings relating environment variables commands present removed windows registry key see two files thus contain settings preferences configure global environment computer boot phase starting new virtual dos machine vdm specify edit startup values windows 98 would present codice_2 file user must edit following windows registry key troubleshooting crash recovery windows cd-rom windows startup disk user-createable floppy disk known emergency boot disk ebd allowed booting real mode ms-dos possible restore real mode dos functionality various unofficial means additionally registry setting exists re-enables restart ms-dos mode option shutdown dialog box unlike past versions windows 9x windows entirely aimed home users thus certain enterprise-oriented features removed several features predecessors work officially unsupported microsoft windows including automated installation active directory client services system policy editor personal web server asp features supported predecessors windows 98 windows 95 resource kit publication targeted towards system administrators never published windows features removed never updated work windows included microsoft fax quickview drivespace well gui fat32 conversion tool several windows explorer commands removed windows windows heavily panned many users critics mainly due stability issues due many bugs glitches windows considered one worst operating systems time pc world article dubbed windows mistake edition placed 4th worst tech products time feature 2006 article states shortly appeared late 2000 users reported problems installing getting run getting work hardware software getting stop running byron hinson julien jay writing activewin took appreciative look operating system removal real mode dos noted removal dos clearly made difference windows terms stability far less blue screens death seen booting speed greatly increased recommendation operating system upgrade users windows 95 98 stated windows n't revolutionary os clear microsoft focused efforts make user-friendly stable packed full multimedia options result great enhancements added really worth wait along windows 2000 nt family windows last version windows lacked product activation system restore suffered bug date-stamping functionality could cause system restore date-stamp snapshots taken 8 september 2001 incorrectly could prevent system restore locating snapshots cause system restore process fail microsoft released update fix problem one common errors startup shutdown computer would display blue screen death instead starting shutting well logo graphic failing load boot microsoft planned stop support windows december 31 2004 however order give customers time migrate newer windows versions particularly developing emerging markets microsoft decided maintain support july 11 2006 support windows 98 also ended date microsoft ended support products company considers obsolete running products expose users security risks 2011 microsoft removed update website windows updates site windows 98 windows 98 se also terminated year windows also contained microsoft java virtual machine caused well windows 98 windows 98 se pulled microsoft developer network end 2003 windows designed handle 512 mb ram default systems larger ram pools may lose stability however depending hardware software configuration sometimes possible manually tweak installation continue working somewhat larger amounts ram well systems 1.5 gb ram may reboot continuously startup windows windows spellings used referring operating system windows used microsoft pc world
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Operating systems
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first responder network authority first responder network authority firstnet united states created middle class tax relief job creation act 2012 mctrjca independent authority within national telecommunications information administration ntia purpose firstnet establish operate maintain interoperable public safety broadband network fulfill objectives congress allotted 7 billion 20 mhz valuable radio spectrum build network first responder network authority board directors team 15 experts firstnet board established part middle class tax relief job creation act 2012 representatives include secretary homeland security attorney general director office management budget permanent members remaining members selected secretary commerce public safety technical network and/or financial expertise construction nationwide firstnet network requires state radio access network ran connect firstnet network core according mctrjca firstnet responsible consulting states local communities tribal governments develop requirements ran deployment plan efforts began may 2013 however state option either allow firstnet create ran opt create ran even state chooses opt receives approval federal communications commission fcc develop ran ran must use firstnet network core must meet firstnet requirements state receive fcc approval must demonstrate following abilities states meet criteria receive fcc approval may apply grant funding ntia calls nationwide broadband system came september 11 2001 federal government working toward system ever since time 9/11 attacks highlighted inability deployed public safety networks handle true crisis situation firstnet early stages creating first nationwide high-speed broadband wireless network providing single interoperable platform law enforcement firefighters paramedics public safety officials every state county locality tribal area. ” april 2016 article spokesman firstnet said “ firstnet going really revolutionize communications technology first responders next-generation technology ’ going save lives ’ going keep first responders safer make communities safer ’ going provide extra situational awareness people field. ” currently around 10,000 different incompatible “ land mobile radio networks first responders u.s. use jobs patchwork different systems get way first responders able effectively communicate emergencies states able opt firstnet new nationwide broadband network firstnet assists states providing guide helps states deploy communications networks interoperability systems federal communications commission national telecommunications information administration also involved coordinating broadband system u.s. senate hearing july 2016 senators brian schatz d-hawaii roger wicker r-mississippi expressed concern firstnet ceo testifying hearing various issues related national broadband system schatz said would rather see firstnet partner states instead establishing 'grantee-grantor relationship wicker said concerned 7 billion budget program enough funding august 2016 firstnet held border security forum phoenix arizona firstnet officials met federal local security officials discuss problems communications networks updates firstnet deployment national broadband wireless network firstnet representatives said lte technology data apps people smart phones help emergency responders public emergencies firstnet headquartered reston virginia technical headquarters boulder colorado authority board created public-private partnership march 2017 build firstnet december 2017 50 states opted network plan questions remained would deployed cost-effective firstnet characterized wasteful post-9/11 initiative journalist steven brill
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Computer architecture
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bumpercar bumpercar mac os x web browser freeverse software aimed towards kids bumpercar contains extensive parental controls including filtering personal information blocking whitelists blacklists time limits full support icra tags version 2 based webkit well technologies omni group
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Internet protocols
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flutter software flutter open-source mobile application development framework created google used develop applications android ios well primary method creating applications google fuchsia first version flutter known codename sky ran android operating system unveiled 2015 dart developer summit stated intent able render consistently 120 frames per second keynote google developer days shanghai google announced flutter release preview 2 last big release flutter 1.0 december 4th 2018 flutter 1.0 released flutter live event denoting first stable version framework major components flutter include flutter apps written dart language make use many language advanced features android windows macos linux via semi-official flutter desktop embedding project flutter runs dart virtual machine features just-in-time execution engine due app store restrictions dynamic code execution flutter apps use ahead-of-time aot compilation ios notable feature dart platform support hot reload modifications source files injected running application flutter extends support stateful hot reload cases changes source code reflected immediately running app without requiring restart loss state feature implemented flutter received widespread praise flutter engine written primarily c++ provides low-level rendering support using google skia graphics library additionally interfaces platform-specific sdks provided android ios flutter engine portable runtime hosting flutter applications implements flutter core libraries including animation graphics file network i/o accessibility support plugin architecture dart runtime compile toolchain developers interact flutter via flutter framework provides modern reactive framework rich set platform layout foundation widgets foundation library written dart provides basic classes functions used construct applications using flutter apis communicate engine ui design flutter typically involves assembling and/or creating various widgets widget flutter represents immutable description part user interface graphics including text shapes animations created using widgets complex widgets created combining many simpler ones however use widgets strictly required build flutter apps alternative option use foundation library methods directly interfacing canvas commands draw shapes text imagery directly screen property flutter utilized frameworks open-source flame game engine flutter framework contains two sets widgets conform specific design languages material design widgets implement google design language name cupertino widgets imitate apple ios design
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Operating systems
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watchguard watchguard formally known watchguard technologies inc seattle washington-based network security vendor products designed protect computer networks outside threats malware ransomware company founded 1996 watchguard founded 1996 seattle software labs inc. first product network firewall called watchguard security management system included watchguard firebox firewall box security appliance along configuration administration software 1997 company changed name watchguard technologies inc july 1999 company went public nasdaq october 2006 company acquired 151 million private equity firms francisco partners vector capital bruce coleman brought interim ceo august 2007 joe wang became company permanent ceo replacing coleman may 2014 ceo wang stepped replaced interim ceo michael kohlsdorf operating partner francisco partners april 2015 kohlsdorf succeeded ceo prakash panjwani announced panjwani kohlsdorf joining watchguard board june 2016 company acquired hawkeye g threat-detection response technology hexis cyber solutions sensage part keyw holding corp october company launched watchguard wi-fi cloud extend network security wi-fi networks august 2017 watchguard acquired datablink provider multi-factor authentication software used secure laptops servers devices january 2018 company acquired percipient networks domain name system service provider july 2018 company announced application called authpoint designed provide multi-factor authentication security businesses company develops security products services businesses three product groups network security secure wi-fi multi-factor authentication network security devices categorized unified threat management utm whereby single device provides multiple security features devices include watchguard dimension network discovery tool allows administrators identify devices network including mobile devices watchguard cloud giving devices access online threat intelligence wi-fi product line consists secure indoor outdoor wave 1 wave 2 802.11ac wi-fi hardware security subscription services watchguard wi-fi cloud management platform used control devices multi-factor authentication group includes company authpoint application multi-factor authentication management reporting tool prevents unauthorized users accessing sensitive cloud applications vpns networks company also issues quarterly security report based feed data watchguard utm appliances installed customer sites report highlights type frequency malicious attacks occurring computer networks
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Computer security
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orange database management monitoring software orange database management monitoring tool manufactured warevalley orange first released december 2001
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Databases
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open cloud computing interface open cloud computing interface occi set specifications delivered open grid forum cloud computing service providers occi set implementations act proofs concept builds upon world wide web fundamentals using representational state transfer rest approach interacting services aim open cloud computing interface development open specification api cloud offerings focus infrastructure-as-a-service iaas based offerings interface extended support platform software service offerings well iaas one three primary segments cloud computing industry compute storage network resources provided services api based review existing service-provider functionality set use cases contributed working group occi boundary api acts service front-end iaas provider ’ internal infrastructure management framework occi provides commonly understood semantics syntax means management domain consumer-to-provider iaas covers management entire life-cycle occi-defined model entities compatible existing standards open virtualization format ovf cloud data management interface cdmi notably serves integration point standardization efforts including distributed management task force internet engineering task force storage networking industry association occi began march 2009 initially led sun microsystems rabbitmq complutense university madrid today working group 250 members includes numerous individuals industry academic parties occi operates umbrella open grid forum ogf using wiki mailing list collaboration implement specific extensions occi particular service iaas paas brokering etc several implementations announced released frameworks build occi apis complementing variety developer tools alternative approaches include use cloud infrastructure management interface cimi related standards set dmtf amazon web services interfaces amazon latter endorsed known standards organization opennebula conducted survey users results showed 38 expose cloud apis users interface sunstone gui 36 mostly use amazon web services api 26 mostly use opennebula ’ occi api occi api offered rocci
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Distributed computing architecture
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saint software saint security administrator ’ integrated network tool computer software used scanning computer networks security vulnerabilities exploiting found vulnerabilities saint scanner screens every live system network tcp udp services service finds running launches set probes designed detect anything could allow attacker gain unauthorized access create denial-of-service gain sensitive information network saint provides support security content automation protocol scap specification unauthenticated vulnerability scanner authenticated vulnerability patch scanner saint also approved scanning vendor payment card industry pci four steps saint scan saint group vulnerabilities according severity type count also provide information particular host group hosts saint describes vulnerabilities locates references common vulnerabilities exposures cve cert advisories iava information assurance vulnerability alerts describes ways correct vulnerabilities many cases saint scanner provides links patches new software versions eliminate detected vulnerabilities vulnerability flaw system device application leveraged attacker could impact security system exploits take advantage vulnerability compromising destructing vulnerable system device application remediation process repairing providing remedy vulnerability thereby eliminating risk exploited vulnerability scanning used identify evaluate security posture network historically scanners developed specific purposes scanning windows desktops applications network devices saint offers heterogeneous scanning identifies vulnerabilities across operating systems desktop applications network devices web applications databases integrated penetration testing tool saintexploit demonstrates path attacker could use breach network quantifies risk network saintexploit includes web site emulator e-mail forgery tool penetration testing tools saint designed simulate internal external real-world attacks type testing identifies methods gaining access target understanding techniques used attackers many levels types penetration testing scope project well defined targets included scope could include popular protocols network devices databases web applications desktop applications various flavors operating systems saint focuses development exploits shell established shell shellcode exploits included offer command shell/direct connection target computer performing testing exploits target operating systems desktop applications databases web applications protocols network devices common exploit types included saintexploit include following • remote exploit – attacks launched across internet network vulnerable target without user previous access system • client exploit – victim must access attacker ’ resource successful attack take place common client exploits include e-mail forgery attacks enticing user visit web site open file • local exploit – order launch local attack attacker must previous access victim also known privilege elevation tunneling case victim machine used launch pad connecting vulnerable targets saint ’ remote management console saintmanager enables enterprise-wide vulnerability scanning browser-based console provides ability centrally manage entire network saint vulnerability scanners single interface saintcloud enables cloud based vulnerability scanning penetration testing compliance audits without download install software saint security administrator integrated network tool network vulnerability scanner based satan security administrator tool analyzing networks developed dan farmer wietse venema released 1995 saint corporation formerly world wide digital security inc. wwdsi continued development released saint july 1998 wwdsi changed name saint corporation january 2002 saint products developed saint corporation headquartered bethesda maryland
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Computer security
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classic monolingual word-sense disambiguation classic monolingual word sense disambiguation evaluation tasks uses wordnet sense inventory largely based supervised semi-supervised classification manually sense annotated corpora first senseval workshop hector sense inventory adopted reason adopting previously unknown sense inventory mainly avoid use popular fine-grained word senses wordnet could make experiments unfair biased however given lack coverage inventories since second senseval workshop wordnet sense inventory adopted wsd exercises require dictionary specify word senses disambiguated corpus language data disambiguated wordnet popular example sense inventory reason adopting hector database senseval-1 wordnet inventory already publicly available comparison methods divided 2 groups amount words test difference consists amount analysis processing assumed former one realistic evaluation although laborious testing results initially latter used evaluation later former included lexical sample organizers choose samples systems tested criticism earlier forays lexical-sample wsd evaluation lexical sample chosen according whim experimenter coincide earlier experimenters selections english senseval sampling frame devised words classified according frequency bnc polysemy level wordnet also inclusion pos-tagging problem matter discussion decided samples words known part speech indeterminants ex 15 noun tasks 13 verb tasks 8 adjectives 5 indeterminates comparison purposes known yet simple algorithms named baselines used include different variants lesk algorithm frequent sense algorithm evaluation wsd systems two main performance measures used system makes assignment every word precision recall called accuracy model extended take account systems return set senses weights occurrence
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Computational linguistics
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poseidon malware poseidon name family malicious computer programs targeting computerized point-of-sale systems cisco talos computer security research laboratory discovered introduced family malware nickname poseidon security blog 20 march 2015 malware attempts steal keystrokes credit card numbers stored system memory scanning ram discover visa mastercard amex issued credit cards credit card data encrypted sent exfiltrated number predefined russian servers commercial remote administration software logmein installed logmein settings modified forcing next remote user enter username password allows username password read keylogger exfiltrated
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Computer security
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yara yara name tool primarily used malware research detection provides rule-based approach create descriptions malware families based textual binary patterns description essentially yara rule name rules consist sets strings boolean expression language used traits perl compatible regular expressions yara originally developed victor alvarez virustotal name either abbreviation yara yet another recursive acronym yet another ridiculous acronym yara default comes modules process pe elf analysis well support open-source cuckoo sandbox
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Computer security
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visual expert visual expert static program analyzer extracting design technical information software source code reverse-engineering used programmers software maintenance modernization optimization designed parse several programming languages time pl/sql transact-sql powerbuilder ... analyze cross-language dependencies addition language source code visual expert used several contexts
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Databases
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hashcash hashcash proof-of-work system used limit email spam denial-of-service attacks recently become known use bitcoin cryptocurrencies part mining algorithm hashcash proposed 1997 adam back described formally back paper hashcash denial service counter-measure similar idea first proposed cynthia dwork moni naor eli ponyatovski 1992 paper pricing via processing combatting junk mail using weakened signature schemes rather simpler efficient hash-based approach introduced hashcash hashcash independent rediscovery proof work concept author aware dwork et al work hashcash cryptographic hash-based proof-of-work algorithm requires selectable amount work compute proof verified efficiently email uses textual encoding hashcash stamp added header email prove sender expended modest amount cpu time calculating stamp prior sending email words sender taken certain amount time generate stamp send email unlikely spammer receiver negligible computational cost verify stamp valid however known way find header necessary properties brute force trying random values answer found though testing individual string easy satisfactory answers rare enough require substantial number tries find answer hypothesis spammers whose business model relies ability send large numbers emails little cost per message cease profitable even small cost spam send receivers verify whether sender made investment use results help filter email header line looks something like header contains header contains recipient email address date message information proving required computation performed presence recipient email address requires different header computed recipient date allows recipient record headers received recently ensure header unique email message sender prepares header appends counter value initialized random number computes 160-bit sha-1 hash header first 20 bits i.e 5 significant hex digits hash zeros acceptable header sender increments counter tries hash 2 possible hash values 2 hash values satisfy criterion thus chance randomly selecting header 20 zeros beginning hash 1 2 approx 10 one million number times sender needs try get valid hash value modeled geometric distribution hence sender average try 2 values find valid header given reasonable estimates time needed compute hash would take one second find efficient method brute force approach known find valid header normal user desktop pc would significantly inconvenienced processing time required generate hashcash string however spammers would suffer significantly due large number spam messages sent technically system implemented following steps hash string passes tests considered valid hash string tests take far less time disk space receiving body content e-mail time needed compute hash collision exponential number zero bits zero bits added doubling amount time needed compute hash additional zero bit expensive spammers generate valid header lines confirming header valid always takes amount time matter many zero bits required valid header since requires single hashing operation hashcash system advantage micropayment proposals applying legitimate e-mail real money involved neither sender recipient need pay thus administrative issues involved micropayment system moral issues related charging e-mail entirely avoided hand hashcash requires potentially significant computational resources expended e-mail sent somewhat difficult tune ideal amount average time one wishes clients expend computing valid header mean sacrificing accessibility low-end embedded systems else running risk hostile hosts challenged enough provide effective filter spam hashcash also fairly simple implement mail user agents spam filters central server needed hashcash incrementally deployed—the extra hashcash header ignored received mail clients understand one plausible analysis concluded one following cases likely either non-spam e-mail get stuck due lack processing power sender spam e-mail bound still get examples include respectively centralized e-mail topology like mailing list server send enormous amount legitimate e-mails botnets cluster farms spammers increase processing power enormously issues may addressed e.g. botnets may expire faster users notice high cpu load take counter-measures mailing list servers registered white lists subscribers hosts thus relieved hashcash challenges represent serious obstacles hashcash deployment remain addressed another projected problem computers continue get faster according moore law difficulty calculations required must increased time however developing countries expected use older hardware means find increasingly difficult participate e-mail system also applies lower-income individuals developed countries afford latest hardware like hashcash cryptocurrencies use hash function proof-of-work system rise cryptocurrency created demand asic-based mining machines although cryptocurrencies use sha-256 hash function asic technology could used create hashcash solvers three orders magnitude faster consumer cpu reducing computational hurdle spammers contrast hashcash mail applications relies recipients set manually amount work intended deter malicious senders bitcoin cryptocurrency network employs different hashing-based proof-of-work challenge enable competitive bitcoin mining bitcoin miner runs computer program collects unconfirmed transactions coin dealers network data form block earn payment miner block accepted network miner discovers trial error nonce number included block yields hash sufficient number leading zero bits meet network difficulty target blocks accepted miners form bitcoin blockchain growing ledger every bitcoin transaction since coin first creation hashcash uses sha-1 hash requires first 20 160 hash bits zero bitcoin proof work uses two successive sha-256 hashes originally required least first 32 256 hash bits zero however bitcoin network periodically resets difficulty level keep average rate block creation 6 per hour january 2019 block 556678 bitcoin network responded deployments ever faster hashing hardware miners hardening requirement first 74 256 hash bits must zero hashcash used potential solution false positives automated spam filtering systems legitimate users rarely inconvenienced extra time takes mine stamp spamassassin able check hashcash stamps since version 2.70 assigning negative score i.e less likely spam valid unspent hashcash stamps however although hashcash plugin initially default still needs configured list address patterns must match hashcash resource field n't actually work default penny post software project sourceforge implements hashcash mozilla thunderbird email client project named historical availability conventional mailing services cost sender one penny see penny post information mailing services history microsoft also designed implemented deprecated open spec similar yet incompatible hashcash email postmark part coordinated spam reduction initiative csri microsoft email postmark variant hashcash implemented microsoft mail infrastructure components exchange outlook hotmail format differences hashcash microsoft email postmark postmark hashes body addition recipient uses modified sha-1 hash function uses multiple sub-puzzles reduce proof work variance like e-mail blogs often fall victim comment spam blog owners used hashcash scripts written javascript language slow comment spammers scripts wp-hashcash claim implement hashcash instead depend javascript obfuscation force client generate matching key require processing power use hashcash algorithm hashcash stamps hashcash patented reference implementation implementations free software hashcash included available many linux distributions rsa made ipr statements ietf client-puzzles context rfc described client-puzzles hashcash rfc included hashcash title referenced hashcash mechanism described known-solution interactive challenge akin client-puzzles hashcash non-interactive therefore known solution case rsa ipr statement apply hashcash hashcash predates march 1997 client-puzzles publication feb 1999 client-puzzles patent filing us7197639 february 2000
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Computer security
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object exchange model object exchange model oem model exchanging semi-structured data object-oriented databases serves basic data model numerous projects stanford university database group including tsimmis lore c3 slight variations oem evolved across different stanford projects lore labels actually parent-child links rather objects example oem object multiple parents different parent objects may use different labels identify object atomic value encoding person name might included one complex object using label author another complex object using label editor c3 additional attributes required object annotate changes object occurred time textual oem interchange format used lore goals interchange format textual encodings oem easy read easy edit easy generate parse program
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Databases
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peter zandan peter a. zandan born 1953 american entrepreneur field market research data science zandan currently global vice chairman hill+knowlton strategies leads company worldwide research operations founder intelliquest information group inc. austin-based global research firm served chairman ceo 1984 1998 taking company public 1996 intelliquest zandan pioneered use electronic surveys internet field market research 1999 zandan founded served ceo zilliant pricing optimization company zandan played active role austin texas community 2014 developed sponsored zandan poll annual survey among austin residents covers variety topics including economy affordability growth education policy issues overall cultural identity austin zandan currently member president circle national academies sciences engineering medicine zandan also serves board klru public television station austin texas member advisory council red mccombs school business ut austin moved austin 1970s zandan earned mba ph.d. evaluation research university texas austin born longmeadow massachusetts zandan received bachelor degree history university massachusetts 1975 latter half 1970s zandan moved mexico pursue international studies several years abroad returned united states earned mba ph.d. evaluation research 1983 university texas zandan founded first major company 1984 name intelliquest intelliquest focused changing way companies performed market research pioneering ‘ disk-by-mail ’ methodologies later utilizing internet based electronic surveys zandan served company chairman ceo 15 years intelliquest fastest growing market research company worldwide 1990s provided new product marketing branding services corporations apple ibm mckinsey co. microsoft hewlett-packard intelliquest provided marketing information technology companies direct marketing services internet marketers additionally supplied information tech markets subscription proprietary project basis zandan leadership intelliquest grew 500 employees offices austin silicon valley new york city london zandan took company public 1996 nasdaq exchange acquired wpp 1999 1998 company bought zandan stepped away day-to-day management operations company pursue interests 1998 peter zandan founded zilliant inc another austin-based corporation zilliant developed leader strategic pricing management providing software solutions enable corporations outline manage e-commerce pricing understood “ internet allows companies better understand customers preferences ” zandan helped develop flagship product called zilliant intelligent pricing solution zips tested real-time customer pricing behavior monitored activity market opportunities offering business-to-business predictive pricing sales applications zilliant grew quickly continues operate successfully peter zandan currently global vice chairman hill+knowlton strategies developed firm reputation management communications research offerings zandan provided assistance international brand development clients financial services energy technology healthcare retail industries specifically zandan leads research+data insights rdi corporation underneath umbrella organization hill+knowlton strategies zandan helped rdi yield data-based insights deliver metrics counsel brand health communication data analytics june 2013 zandan selected member president circle national academy science purpose president circle engage leaders various scientific disciplines engineering medicine effort ensure intellectual financial resources sustain/enhance research president circle honorary association membership acquired invitations presidents three academies along honored 1998 lifetime member mccombs business school advisory council starting zandan served board public television station klru since year also invested advised new media companies including wize inc. klout sold lithium technologies next big sound sold pandora peter zandan angel investing companies next big sound allowed continue remain active part startup company scene peter zandan impacted austin community social analytics work external involvement zandan poll annual report surveys austin-area residents assess attitudes community economy health transportation city longtime citizen austin zandan watched community grow years wanted create objective tool measure austinites felt community evolving zandan provides gift austin community help klru hill+knowlton strategies rdi cambia information group poll expanded areas “ cultural identity ” affordability order increase understanding dialogue key community issues zandan also received austin “ soul city ” business award contributions community co-chair austin 360 summit one-day issues conference austin high-tech executives additionally chairs austin city limits committee member board directors klru-tv growing intelliquest one fastest-growing market research firms 1990s peter zandan received ernst young entrepreneur year award 1993 high technology electronics award represents elite corp men women recognized exceptional entrepreneurial achievements due extensive work austin area peter zandan also awarded “ best visionary ” award austin chronicle weekly newspaper austin texas
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Web technology
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actions semiconductor actions semiconductor co. ltd. chinese fabless semiconductor company founded 2000 headquartered zhuhai guangdong province company 600 employees designs socs tablets digital audio players photo viewers related products following list system-on-chips developed marketed actions semiconductor mainly targeting tablets s1 mp3 players use chipsets designed actions 2012 actions semiconductor produced atm7029 quad-core arm cortex-a5-based soc using vivante corporations gc1000 gpu soc used ainol novo10 hero ii tablet low end tablets q2 2014 actions reported fourth largest supplier tablet processors chinese market one point actions sued sigmatel sigmatel prevailing findings actions infringed upon sigmatel directly copying asics designed sigmatel world leader mp3 asic market sigmatel later sold freescale semiconductor
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Computer architecture
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fragmentation computing computer storage fragmentation phenomenon storage space used inefficiently reducing capacity performance often exact consequences fragmentation depend specific system storage allocation use particular form fragmentation many cases fragmentation leads storage space wasted case term also refers wasted space systems e.g fat file system space used store given data e.g files regardless degree fragmentation none extreme three different related forms fragmentation external fragmentation internal fragmentation data fragmentation present isolation conjunction fragmentation often accepted return improvements speed simplicity analogous phenomena occur resources processors see computer program requests blocks memory computer system blocks allocated chunks computer program finished chunk free chunk back system making available later allocated another program size amount time chunk held program varies lifespan computer program request free many chunks memory program started free memory areas long contiguous time use long contiguous regions become fragmented smaller smaller contiguous areas eventually may become impossible program obtain large contiguous chunks memory due rules governing memory allocation computer memory sometimes allocated needed example memory provided programs chunks divisible 4 8 16 result program requests perhaps 29 bytes actually get chunk 32 bytes happens excess memory goes waste scenario unusable memory contained within allocated region arrangement termed fixed partitions suffers inefficient memory use process matter small occupies entire partition waste called internal fragmentation unlike types fragmentation internal fragmentation difficult reclaim usually best way remove design change example dynamic memory allocation memory pools drastically cut internal fragmentation spreading space overhead larger number objects external fragmentation arises free memory separated small blocks interspersed allocated memory weakness certain storage allocation algorithms fail order memory used programs efficiently result although free storage available effectively unusable divided pieces small individually satisfy demands application term external refers fact unusable storage outside allocated regions example consider situation wherein program allocates 3 continuous blocks memory frees middle block memory allocator use free block memory future allocations however use block memory allocated larger size free block external fragmentation also occurs file systems many files different sizes created change size deleted effect even worse file divided many small pieces deleted leaves similarly small regions free spaces data fragmentation occurs collection data memory broken many pieces close together typically result attempting insert large object storage already suffered external fragmentation example files file system usually managed units called blocks clusters file system created free space store file blocks together contiguously allows rapid sequential file reads writes however files added removed changed size free space becomes externally fragmented leaving small holes place new data new file written existing file extended operating system puts new data new non-contiguous data blocks fit available holes new data blocks necessarily scattered slowing access due seek time rotational latency read/write head incurring additional overhead manage additional locations called file system fragmentation writing new file known size empty holes larger file operating system avoid data fragmentation putting file one holes variety algorithms selecting potential holes put file heuristic approximate solution bin packing problem best fit algorithm chooses smallest hole big enough worst fit algorithm chooses largest hole first-fit algorithm chooses first hole big enough next fit algorithm keeps track file written next fit algorithm faster first fit turn faster best fit speed worst fit compaction eliminate external fragmentation data fragmentation eliminated rearranging data storage related pieces close together example primary job defragmentation tool rearrange blocks disk blocks file contiguous defragmenting utilities also attempt reduce eliminate free space fragmentation moving garbage collectors also move related objects close together called compacting improve cache performance four kinds systems never experience data fragmentation—they always store every file contiguously four kinds significant disadvantages compared systems allow least temporary data fragmentation compared external fragmentation overhead internal fragmentation account little loss terms wasted memory reduced performance defined formula_1 fragmentation 0 means free memory single large block fragmentation 90 example 100 mb free memory present largest free block memory storage 10 mb external fragmentation tends less problem file systems primary memory ram storage systems programs usually require ram storage requests fulfilled contiguous blocks file systems typically designed able use collection available blocks fragments assemble file logically appears contiguous therefore highly fragmented file many small files deleted full volume new file size equal newly freed space created new file simply reuse fragments freed deletion deleted one file new file fragmented old file case barrier using highly fragmented free space create new file ram hand storage systems used often assemble large block meet request small noncontiguous free blocks request fulfilled program proceed whatever needed memory unless reissue request number smaller separate requests severe problem caused fragmentation causing process system fail due premature resource exhaustion contiguous block must stored stored failure occurs fragmentation causes occur even enough resource contiguous amount example computer 4 gib memory 2 gib free memory fragmented alternating sequence 1 mib used 1 mib free request 1 contiguous gib memory satisfied even though 2 gib total free order avoid allocator may instead failing trigger defragmentation memory compaction cycle resource reclamation major garbage collection cycle hope able satisfy request allows process proceed severely impact performance fragmentation causes performance degradation number reasons basically fragmentation increases work required allocate access resource example hard drive tape drive sequential data reads fast seeking different address slow reading writing fragmented file requires numerous seeks thus much slower addition causing greater wear device resource fragmented allocation requests simply satisfied returning single block start free area however fragmented request requires either searching large enough free block may take long time fulfilling request several smaller blocks possible results allocation fragmented requiring additional overhead manage several pieces subtler problem fragmentation may prematurely exhaust cache causing thrashing due caches holding blocks individual data example suppose program working set 256 kib running computer 256 kib cache say l2 instruction+data cache entire working set fits cache thus executes quickly least terms cache hits suppose 64 translation lookaside buffer tlb entries 4 kib page memory access requires virtual-to-physical translation fast page cache tlb working set unfragmented fit onto exactly 64 pages page working set 64 pages memory lookups served cache however working set fragmented fit 64 pages execution slow due thrashing pages repeatedly added removed tlb operation thus cache sizing system design must include margin account fragmentation memory fragmentation one severe problems faced system managers time leads degradation system performance eventually memory fragmentation may lead complete loss application-usable free memory memory fragmentation kernel programming level problem real-time computing applications fragmentation levels reach high 99 may lead system crashes instabilities type system crash difficult avoid impossible anticipate critical rise levels memory fragmentation however may possible system continue running programs case excessive memory fragmentation well-designed system able recover critical fragmentation condition moving memory blocks used system order enable consolidation free memory fewer larger blocks worst case terminating programs free memory defragmenting resulting sum total free memory least avoid true crash sense system failure allow system continue running programs save program data etc also important note fragmentation phenomenon system software design different software susceptible fragmentation different degrees possible design system never forced shut kill processes result memory fragmentation fragmentation best known problem memory allocation analogous phenomena occur resources notably processors example system uses time-sharing preemptive multitasking check process blocked process executes part time slice blocks proceed remainder time slice wastes time resulting internal fragmentation time slices fundamentally time-sharing causes external fragmentation processes due running fragmented time slices rather single unbroken run resulting cost process switching increased cache pressure multiple processes using caches result degraded performance concurrent systems particularly distributed systems group processes must interact order progress processes scheduled separate times separate machines fragmented across time machines time spent waiting communicating severely degrade performance instead performant systems require coscheduling group flash file systems several different kinds internal fragmentation involving dead space dark space
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Computer file systems
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ddos attacks october 2011 south korean by-election ddos attacks october 2011 south korean by-election allegedly two separate distributed denial-of-service ddos attacks occurred october 26 2011 attacks took place october 2011 seoul mayoral by-election targeted websites national election commission nec then-mayoral candidate park won-soon investigators assert attacks carried hopes suppressing young voters benefit grand national party aide grand national party legislator choi gu-sik found responsible attacks attacks consisted two separate denial-of-service attacks independent national election commission mayoral candidate park won-soon carried help botnet 200 infected computers attacks conducted morning citizens -- particularly young voters looking vote work -- would expected look polling station locations theorized attacks conducted belief may reduce voter turnout benefit grand national party candidate na kyung-won police stated attack nec lasted two hours specifically impacting part website information polling locations park won-soon website attacked twice day national police agency later revealed aide grand national part lawmaker referred media surname gong responsible two attacks national police agency later arrested gong four associates researchers however questioned official narrative doubts raised whether gong technical expertise resources pull attack others pointed ddos attack would unusual parts website offline online suggesting perhaps technical failure instead events caused collective panic amongst gnp members often denounce online activities south korean progressives exposure role attacks led choi gu-sik officially resigning position lawmaker along several members gnp wake scandal reformists conservative grand national party put pressure core members party closely affiliated lee myung-bak government turn led park geun-hye brought back spotlight reorganize gnp 30 university student associations made joint statement calling thorough investigation attacks
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Computer security
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ibm thinkpad t20 series ibm thinkpad t20 series series notebook computers introduced may 2000 ibm successor 600 series first model t-series exists today lenovo ownership four models produced t20 t21 t22 t23 series succeeded may 2002 thinkpad t30 produced july 2003 t20 series successor 600 series adding new features s-video output ethernet port ultrabay 2000 hot-swappable bay graphics card upgraded 4mb neomagic 256zx used 600x 8mb s3 savage 16mb t23 models capable rendering 3d graphics hardware thinkpad t23 also first thinkpad laptop model offer optional wifi connection via mini-pci card wireless antennas built lid select upper-end models t20 series originally shipped either windows 98 windows 2000 linux later t23 models shipping windows xp t20 models capable running windows 3.x windows 95 windows nt 4.0 os/2 warp 4 windows well various linux distributions additionally t23 capable running windows vista windows 7 least 512mb memory one common problem earlier t20 series hardware defect machine would suddenly stop working blink hard drive power indicators rendering machine unable power known blink death addition t23 models rear memory slot may fail rendering machine able use 512mb memory rather 1gb another common issue t23 one coils near cpu breaks motherboard due cold solder joints causing sorts weird issues like unable boot hard lockups/freezes thinkpad series
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Computer architecture
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openroad openroad stands open rapid object application development software product actian corporation openroad fourth-generation programming language 4gl include suite development tools built-in integrated development environment ide written openroad code repository allowing applications developed deployed microsoft unix/linux platforms history openroad closely tied ingres relational database openroad started early 1990s product called windows 4gl ingres re-badged openingres new name openroad born since time number major developments ingres product set marketed ask corporation computer associates ingres corporation actian popular governments north west europe found many government departments openroad née windows4gl appeared beta form sun platform 1991 windows4gl 1.0 available british universities special license agreement development environment known sapphire editor sapphire editor allowed creation complex gui interfaces using ide rather large volumes motif code resource files one first environments enable rapid prototyping gui clients windows4gl 2.0 introduced microsoft windows compatibility debugger openroad 3.0 became stable ms windows openroad 3.5 1 became stable openroad 4.1 introduced interface activex controls providing access activex control attributes methods within language mechanism often requires 'wrapper dlls written handle data type issues one 2000 character limit strings text interpreted language uses runtime distributable client process 'image files thus dll .net dependency issues ms windows activex aside possible use images environment unix vms ms windows version 3.51 however portability issues gui environments mostly related font differences made difficult macintosh beta version produced 3.51 unix environments used commercial pc emulator give native capability possibly one hurdles road open source status across platforms variations distribution include fat client requires ingres net communication thin eclient used without ingres net needs use application server instead dcom finally mclient mobile windows clients http services required interface application server openroad 2006 5.0+ went general available december 2006 openroad 5.1 went generally available apr 2011 defining feature release general-purpose system classes xml support allow creation parsing arbitrary xml documents without need create additional user classes use external components 3gl procedures external class libraries providing xml based export file format documented human readable produce clean differences different revisions file allow changes merged allow openroad source components managed many different software configuration management scm systems openroad 2006 5.5 unicode support special limited release openroad 6.0 current general release includes additional unicode support 5.5 syntax openroad closely linked ingres database direct support embedded sql similar way event based programming languages code placed groups related windows/system events syntax similar microsoft visual basic allowing openroad users quickly adapt visual basic help intellisense intellisense still available q2 2008 openroad ide however editors like textpad syntax files allow colour-coding source files using key word recognition openroad comes system classes following functionality openroad application deployed following clients thin client web windows various flavours linux/unix support n-tier systems using openroad application server application server deployed windows linux/unix platforms built-in support ingres database one following using product called enterprise access oracle sql server db2 allows client use sql syntax target databases product links community links mailing lists webcasts
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Programming language topics
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compartmentalization information security compartmentalization information security whether public private limiting access information persons entities need-to-know basis perform certain tasks originated handling classified information military intelligence applications dates back antiquity successfully used keep secret greek fire basis compartmentalization idea fewer people know details mission task risk likelihood information compromised fall hands opposition decreased hence varying levels clearance within organizations exist yet even someone highest clearance certain compartmentalized information identified codewords referring particular types secret information may still restricted certain operators even lower overall security clearance information marked way said codeword–classified one famous example ultra secret documents marked top secret ultra top secret marked security level ultra keyword restricted readership cleared read ultra documents compartmentalization also used commercial security engineering technique protect information medical records example compartmentalization manhattan project personnel oak ridge constructed operated centrifuges isolate uranium-235 naturally occurring uranium know exactly knew know parts weapon separately designed teams know parts interacted
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Computer security
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enterprise javabeans enterprise javabeans ejb one several java apis modular construction enterprise software ejb server-side software component encapsulates business logic application ejb web container provides runtime environment web related software components including computer security java servlet lifecycle management transaction processing web services ejb specification subset java ee specification ejb specification originally developed 1997 ibm later adopted sun microsystems ejb 1.0 1.1 1999 enhanced java community process jsr 19 ejb 2.0 jsr 153 ejb 2.1 jsr 220 ejb 3.0 jsr 318 ejb 3.1 jsr 345 ejb 3.2 ejb specification provides standard way implement server-side also called back-end 'business software typically found enterprise applications opposed 'front-end user interface software software addresses types problem solutions problems often repeatedly re-implemented programmers enterprise javabeans intended handle common concerns persistence transactional integrity security standard way leaving programmers free concentrate particular parts enterprise software hand ejb specification details application server provides following responsibilities additionally enterprise javabean specification defines roles played ejb container ejbs well deploy ejbs container note current ejb 3.2 specification detail application server provides persistence task delegated jpa specification instead details business logic easily integrate persistence services offered application server businesses found using ejbs encapsulate business logic brought performance penalty original specification allowed remote method invocation corba optionally protocols even though large majority business applications actually require distributed computing functionality ejb 2.0 specification addressed concern adding concept local interfaces could called directly without performance penalties applications distributed multiple servers ejb 3.0 specification jsr 220 departure predecessors following new light-weight paradigm ejb 3.0 shows influence spring use plain java objects support dependency injection simplify configuration integration heterogeneous systems gavin king creator hibernate participated ejb 3.0 process outspoken advocate technology many features originally hibernate incorporated java persistence api replacement entity beans ejb 3.0 ejb 3.0 specification relies heavily use annotations feature added java language 5.0 release convention configuration enable much less verbose coding style accordingly practical terms ejb 3.0 much lightweight nearly completely new api bearing little resemblance previous ejb specifications following shows basic example ejb looks like code defines service class persisting customer object via o/r mapping ejb takes care managing persistence context addcustomer method transactional thread-safe default demonstrated ejb focuses business logic persistence knows nothing particular presentation ejb used class e.g web layer follows defines javaserver faces jsf backing bean ejb injected means ejb annotation addcustomer method typically bound ui component button contrary ejb backing bean contain business logic persistence code delegates concerns ejb backing bean know particular presentation ejb knowledge ejb container holds two major types beans stateful session beans business objects state keep track calling client dealing throughout session thus access bean instance strictly limited one client time concurrent access single bean attempted anyway container serializes requests via accesstimeout annotation container instead throw exception stateful session beans state may persisted passivated automatically container free memory client n't accessed bean time jpa extended persistence context explicitly supported stateful session beans stateless session beans business objects state associated however access single bean instance still limited one client time concurrent access bean prohibited concurrent access single bean attempted container simply routes request different instance makes stateless session bean automatically thread-safe instance variables used single method call client bean contents instance variables guaranteed preserved across different client method calls instances stateless session beans typically pooled second client accesses specific bean right method call made first client finished might get instance lack overhead maintain conversation calling client makes less resource-intensive stateful beans singleton session beans business objects global shared state within jvm concurrent access one bean instance controlled container container-managed concurrency cmc bean bean-managed concurrency bmc cmc tuned using lock annotation designates whether read lock write lock used method call additionally singleton session beans explicitly request instantiated ejb container starts using startup annotation message driven beans business objects whose execution triggered messages instead method calls message driven bean used among others provide high level ease-of-use abstraction lower level jms java message service specification may subscribe jms message queues message topics typically happens via activationconfig attribute messagedriven annotation added ejb allow event-driven processing unlike session beans mdb client view local/remote/no-interface i. e. clients look-up mdb instance mdb listens incoming message example jms queue topic processes automatically jms support required java ee spec message driven beans support messaging protocols protocols may asynchronous also synchronous since session beans also synchronous asynchronous prime difference session- message driven beans synchronicity difference object oriented method calling messaging ejbs deployed ejb container typically within application server specification describes ejb interacts container client code interacts container/ejb combination ejb classes used applications included package package service provider interface used ejb container implementations clients ejbs instantiate beans directly via java new operator instead obtain reference via ejb container reference usually reference implementation bean proxy either dynamically implements local remote business interface client requested dynamically implements sub-type actual bean proxy directly cast interface bean client said 'view ejb local interface remote interface bean type respectively correspond local view remote view no-interface view proxy needed order give ejb container opportunity transparently provide cross-cutting aop-like services bean like transactions security interceptions injections remoting example client invokes method proxy first start transaction help ejb container call actual bean method bean method returns proxy ends transaction i.e committing rollback transfers control back client ejb container responsible ensuring client code sufficient access rights ejb security aspects declaratively applied ejb via annotations ejb containers must support container managed acid transactions bean managed transactions container-managed transactions cmt default active calls session beans explicit configuration needed behavior may declaratively tuned bean via annotations needed configuration later overridden deployment descriptor tuning includes switching transactions whole bean specific methods requesting alternative strategies transaction propagation starting joining transaction strategies mainly deal happen transaction n't already progress time bean called following variations supported alternatively bean also declare via annotation wants handle transactions programmatically via jta api mode operation called bean managed transactions bmt since bean handles transaction instead container jms java message service used send messages beans clients let clients receive asynchronous messages beans mdbs used receive messages clients asynchronously using either jms queue topic alternative injection clients ejb obtain reference session bean proxy object ejb stub using java naming directory interface jndi alternative used cases injection available non-managed code standalone remote java se clients necessary programmatically determine bean obtain jndi names ejb session beans assigned ejb container via following scheme entries square brackets denote optional parts single bean obtained name matching patterns depending 'location client clients module required bean use module scope larger scopes clients application required bean use app scope higher etc e.g code running module customerservice bean given example shown earlier article could use following code obtain local reference communication client written java programming language session bean expose remote-view via remote annotated interface allows beans called clients jvms may located remote systems point view ejb container code another jvm remote stateless- singleton session beans may also expose web service client view remote communication via wsdl soap plain xml follows jax-rpc jax-ws specifications jax-rpc support however proposed future removal support jax-ws session bean annotated webservice annotation methods exposed remotely webmethod annotation.. although ejb specification mention exposure restful web services way explicit support form communication jax-rs specification explicitly support ejb following jax-rs spec stateless- singleton session beans root resources via path annotation ejb business methods mapped resource methods via get put post delete annotations however count web service client view used exclusively jax-ws jax-rpc communication via web services typical clients written java programming language also convenient java clients trouble reaching ejb server via firewall additionally web service based communication used java clients circumvent arcane ill-defined requirements so-called client-libraries set jar files java client must class-path order communicate remote ejb server client-libraries potentially conflict libraries client may already instance client also full java ee server conflict deemed hard impossible resolve ejb 2.1 earlier ejb provide java implementation class two java interfaces ejb container created instances java implementation class provide ejb implementation java interfaces used client code ejb ejb 2.1 earlier ejb specification required deployment descriptor present needed implement mechanism allowed ejbs deployed consistent manner regardless specific ejb platform chosen information bean deployed name home remote interfaces whether store bean database etc specified deployment descriptor deployment descriptor xml document entry ejb deployed xml document specifies following information ejb old ejb containers many vendors required deployment information ejb specification would require additional information separate xml files configuration file format ejb platform vendor generally provided tools would read deployment descriptor possibly generated set classes would implement deprecated home remote interfaces since ejb 3.0 jsr 220 xml descriptor replaced java annotations set enterprise bean implementation source level although still possible use xml descriptor instead addition annotations xml descriptor annotations applied attribute within enterprise bean xml definition overrides corresponding source-level annotation although xml elements also additive e.g. activation-config-property xml different name already defined via activationconfigproperty annotation added instead replacing existing properties starting ejb 3.1 ejb specification defines two variants ejb container full version limited version limited version adheres proper subset specification called ejb 3.1 lite part java ee 6 web profile subset full java ee 6 specification ejb 3.1 lite excludes support following features ejb 3.2 lite excludes less features particularly longer excludes asynchronous schedule/ timeout schedule support persistent attribute full ejb 3.2 support complete excluded list ejb 3.2 lite ejb 3.2 final release 2013-05-28 jsr 345 enterprise javabeans 3.2 relatively minor release mainly contained specification clarifications lifted restrictions imposed spec time appeared serve real purpose existing full ejb features also demanded ejb 3 lite functionality proposed pruned ejb 3.1 indeed pruned made optional following features added ejb 3.1 final release 2009-12-10 jsr 318 purpose enterprise javabeans 3.1 specification simplify ejb architecture reducing complexity developer point view also adding new functionality response needs community ejb 3.0 final release 2006-05-11 jsr 220 major changes release made much easier write ejbs using 'annotations rather complex 'deployment descriptors used version 2.x use home remote interfaces ejb-jar.xml file also longer required release replaced business interface bean implements interface ejb 2.1 final release 2003-11-24 jsr 153 major changes ejb 2.0 final release 2001-08-22 jsr 19 major changes overall goals ejb 1.1 final release 1999-12-17 major changes goals release 1.1 ejb 1.0 1998-03-24 announced javaone 1998 sun third java developers conference march 24 27 goals release 1.0
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Programming language topics
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java transaction api java transaction api jta one java enterprise edition java ee apis enables distributed transactions done across multiple x/open xa resources java environment jta specification developed java community process jsr 907 jta provides x/open xa architecture transaction manager transaction processing monitor tp monitor coordinates transactions across multiple resources databases message queues resource resource manager resource manager typically api manipulating resource example jdbc api work relational databases addition resource manager allows tp monitor coordinate distributed transaction resource managers finally application communicates tp monitor begin commit roll back transactions application also communicates individual resources using api modify resource jta api consists classes two java packages jta modelled x/open xa architecture defines two different apis demarcating transaction boundaries distinguishes application server ejb server application component provides interface used application server begin commit roll back transactions provides different interface used general client code servlet ejb manage transactions jta architecture requires resource manager must implement interface order managed tp monitor stated previously resource specific api instance java transaction api consists three elements high-level application transaction demarcation interface high-level transaction manager interface intended application server standard java mapping x/open xa protocol intended transactional resource manager interface provides application ability control transaction boundaries programmatically interface may used java client programs ejb beans method starts global transaction associates transaction calling thread transaction-to-thread association managed transparently transaction manager support nested transactions required usertransaction.begin method throws notsupportedexception calling thread already associated transaction transaction manager implementation support nested transactions transaction context propagation application programs provided underlying transaction manager implementations client server machines transaction context format used propagation protocol dependent must negotiated client server hosts example transaction manager implementation jts specification use transaction context propagation format specified corba ots 1.1 specification transaction propagation transparent application programs annotation provides application ability control transaction boundaries declaratively annotation applied class java ee specification defines managed bean includes cdi managed beans code sample illustrates usage transactional request scoped cdi managed bean transactional behavior configured via attribute annotation available options closely mirror ejb specification annotation provides application ability declare scope bean lives tied time given transaction active code sample illustrates usage transactionscoped request scoped cdi managed bean method foo first called managed instance examplebean subsequently method bar called number printed 0 1 method transaction therefore instance txscopedbean number 1 set call foo therefore seen call bar ejb servers required support usertransaction interface use ejb beans bean value annotation called bean-managed transactions bmt usertransaction interface exposed ejb components either ejbcontext interface using getusertransaction method directly via injection using general codice_1 annotation thus ejb application interface transaction manager directly transaction demarcation instead ejb bean relies ejb server provide support transaction work defined enterprise javabeans specification underlying interaction ejb server tm transparent application burden implementing transaction management ejb container server provider code sample illustrates usage usertransaction via bean-managed transactions ejb session bean alternatively usertransaction obtained sessioncontext note though example codice_2 annotation omitted jta transaction automatically started whenever codice_3 called automatically committed rolled back codice_3 exited making use usertransaction thus necessary ejb programming might needed specialized code usertransaction available codice_5 jta implementation installed environment
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Programming language topics
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java naming directory interface java naming directory interface jndi java api directory service allows java software clients discover look data resources form java objects via name like java apis interface host systems jndi independent underlying implementation additionally specifies service provider interface spi allows directory service implementations plugged framework information looked via jndi may supplied server flat file database choice implementation used typical uses jndi include java rmi java ee apis use jndi api look objects network api provides spi portion allows support practically kind naming directory service including sun microsystems first released jndi specification march 10 1997. current version jndi 1.2 jndi java naming directory interface organizes names hierarchy name string com.example.ejb.mybean name also object implements codice_1 interface however string common way name object name bound object directory storing either object reference object directory service identified name jndi api defines context specifies look object initial context typically used starting point simplest case initial context must created using specific implementation extra parameters required implementation initial context used look name initial context analogous root top directory tree file system example creating initial context context used look previously bound names context example alternative code context object also configured adding jndi.properties file classpath containing initial context factory class name provider url code reduced shown context used look previously bound names context example attributes may attached special entries called directories directories enable searching objects associated attributes directories type context restrict name space much like directory structure file system
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Internet protocols
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blue coat systems blue coat systems company provided hardware software services designed cybersecurity network management 2016 acquired folded symantec company known cacheflow 2002 company broad security portfolio including hardware software services company best known web gateway appliances scan internet traffic security threats authenticate users manage encrypted traffic well products monitor filter employee internet activity also produced consumer products parental control software company products initially sold internet service providers later products intended large companies march 1996 company founded cacheflow inc. redmond washington michael malcolm computer scientist professor university waterloo joe pruskowski doug crow company initially raised 1 million seed money dozen angel investors company goal develop appliances would increase website speed storing frequently accessed web data cache october 1996 benchmark capital purchased 25 company 2.8 million equivalent price 87.5 cents per share february 1997 company raised 5.1 million december 1997 u.s. venture partners acquired 17 company 6 million 1997 company moved headquarters silicon valley january 1998 company released first product cacheflow 1000 cached website objects users likely use repeatedly increase load speed october 1999 cacheos operating system released april 1998 company released cacheflow 100 mid-1998 dot-com bubble company made first sales earning 809,000 three months investors started pushing initial public offering ipo march 1999 technology crossover ventures invested 8.7 million 7 company equivalent price 4.575 per share september 1999 company released cacheflow 500 list price 9,995 competitive review caching appliances pc magazine gave cacheflow 500 editor choice editor said excellent performance plug-and-go setup good management tools review noted noteworthy features dns caching object pipelining techniques allowed page data delivered parallel rather sequential streams early november 1999 marc andreessen invested 3.1 million shares price 11.04 per share november 19 1999 peak dot-com bubble company became public company via initial public offering raising 132 million shares rose fivefold first day trading however company profitable product unproven time company 3.6 million revenue 6.6 million losses prior 3 months company initially hoped price shares 11-13 raise 50 million due strong demand priced shares 26 one month later traded high 182 1999 board directors member andrew rachleff benchmark capital investor brought brian nesmith sold company ipsilon networks nokia 120 million chief executive officer 2000 introduced cacheflow server accelerator product family offloads content delivery tasks web servers tests network world found server accelerator 725 increased website load speed eight-fold cacheflow client accelerator 600 product family also introduced 2000 company first product family corporate networks caching web multimedia content directly corporate network revenues grew 7 million 1998 29 million 1999 97 million 2001 already 25 overall market caching 35 caching appliance market still profitable march 2000 company integrated products akamai technologies may 2000 company updated cacheflow os cache multimedia content including realnetworks realsystem microsoft windows media apple quicktime formats june 2000 company acquired springbank networks internet device company 180 million december 2000 company acquired entera digital content streaming company 440 million 2001 new features specifically streaming media introduced name ciq later 2001 company renamed blue coat systems focus security appliances simultaneously released sg800 appliance sat behind corporate firewalls filter website traffic viruses worms harmful software custom operating system called security gateway provided many security features partners like symantec trend micro company lost 97 value october 2000 march 2001 dot-com bubble burst company continued lose money 2002 several competing internet caching companies abandoned market due slow adoption caching technology cacheflow revenues came security products february 2002 company closed redmond wa office laid 60 workers around dozen redmond workers offered transfers sunnyvale ca office april 2002 company launched fifth version operating system security gateway 600/6000 series company newest product family range security features authentication internet use policies virus scanning content filtering bandwidth restrictions streaming video applications august 2002 company started adding security features also august 2002 company changed name blue coat systems new name intended evoke image police officer guard focusing internet security appliances products primarily used control monitor secure internet use employees example company could limit employee access online gaming video streaming well scan attachments viruses shift focus followed smaller losses revenues first eventually company growth losses 2002 rename 247 million half prior year losses 2003 company 250 employees 150 million annual revenue 2003 3 new products introduced small medium-sized businesses smbs 50 100 250 users bundles websense secure computing although websense partnership later least partially dismantled two vendors slinging mud var community followed second generation proxysg product family added security features instant messaging review eweek said new proxysg line effective easy deploy ongoing maintenance fees expensive october 2003 company acquired ositis software maker antivirus appliances 1.36 million july 2004 company acquired cerberian url filtering company 17.5 million 2005 company introduced anti-spyware appliance called spyware interceptor following year announced upcoming wan optimization products followed ssl-vpn security appliances secure remote connections 2005 company profitable first time 2006 company introduced free web-tool k9 web protection monitor internet traffic block certain websites identify phishing scams november 2008 review pc world gave 4.25 5 stars march 2006 company acquired permeo technologies end point security company 60 million june 2006 company acquired netcache assets netapp involved proxy caching 30 million june 2008 company acquired packeteer engaged wan optimization 268 million 2009 company introduced plugin packetshaper throttle applications spotify review packetshaper 12000 pro gave four five stars review said wo n't find superior wan traffic management anywhere else hardware platform could date considering price november 2009 company went restructuring included layoffs 280 1,500 employees closing facilities latvia new jersey netherlands february 2010 company acquired s7 software solutions research development firm based bangalore 5.25 million august 2010 michael j. borman named president ceo company august 2011 ceo michael borman fired failing meet performance goals replaced greg clark december 2011 thoma cressey bravo acquired company 1.3 billion march 2012 david murphy named chief operating officer president company december 2012 company acquired crossbeam systems maker x-series security appliances may 2013 company acquired solera networks involved big data security december 2013 company acquired norman shark anti malware firm 2014 elastica technology incorporated blue coat products audit subscription service merged blue coat appfeed proxysg gateways june 2015 company acquired perspecsys involved cloud security also march 2015 company integrated technologies acquisitions norman shark solera networks create cloud-based product family called global intelligence network also march 2015 company pressured security researcher raphaël rigo canceling talk syscan '15 although raphaël talk contain information vulnerabilities proxysg platform company still cited concerns talk going provide information useful ongoing security assessments proxysg blue coat canceling talk met harsh criticism various prominent security researchers professionals alike generally welcome technical information various security products widely used march 2015 bain capital acquired company thoma bravo 2.4 billion bain indicated hoped launch another ipo several months later anonymous sources said company looking investment banks purpose august 2015 company launched alliance ecosystem endpoint detection response edr share information security threats across vendors companies first channel program started march cloud ready partner program announced following april november 2015 company acquired elastica involved cloud security 280 million 2015 company 200 million annual profits 600 million revenues 50 increase 2011 june 2 2016 company filed plans initial public offering however june 13 2016 company abandoned ipo plans announced symantec agreed acquire company 4.65 billion acquisition completed august 1 2016 company products integrated symantec blue coat ceo greg clark named ceo symantec blue coat coo michael fey named president coo symantec blue coat devices known dual-use technology used defend corporate networks governments censor monitor public internet traffic appliances see types encrypted traffic block websites record website traffic october 2011 u.s. government examined claims made telecomix hacktivist group syria using blue coat systems products internet censorship telecomix released 54gb log data alleged taken 7 blue coat web gateway appliances depict search terms including israel proxy blocked country using appliances company later acknowledged systems used syria asserted equipment sold intermediaries dubai use iraqi governmental agency despite systems consistently sending heartbeat pings directly back blue coat company claimed monitoring logs identify country appliance communicating blue coat announced would halt providing updates support services systems operating syria april 2013 bureau industry security announced 2.8 million civil settlement computerlinks fzco dubai reseller violations export administration regulations related transfer syria blue coat products april 2013 blue coat systems personnel caught red handed monitoring tracking commenting edward snowden articles authored glenn greenwald guardian company devices also used block public viewing certain websites bahrain qatar u.a.e. among others 2013 citizen lab published 3 reports regarding company devices found countries known using technology violate human rights identified 61 countries using blue coat devices including known censoring surveilling citizens internet activity china egypt russia venezuela however remains unclear exactly technologies used experts say tools could empower repressive governments spy opponents
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Computer security
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identity management identity management idm also known identity access management iam framework policies technologies ensuring proper people enterprise appropriate access technology resources idm systems fall overarching umbrella security data management identity access management systems identify authenticate authorize individuals utilizing resources also hardware applications employees need access identity access management solutions become prevalent critical recent years regulatory compliance requirements become increasingly rigorous complex addresses need ensure appropriate access resources across increasingly heterogeneous technology environments meet increasingly rigorous compliance requirements terms identity management idm identity access management used interchangeably area identity access management identity-management systems products applications platforms manage identifying ancillary data entities include individuals computer-related hardware software applications idm covers issues users gain identity roles sometimes permissions identity grants protection identity technologies supporting protection e.g. network protocols digital certificates passwords etc. identity management idm task controlling information users computers information includes information authenticates identity user information describes information actions authorized access and/or perform also includes management descriptive information user information accessed modified managed entities typically include users hardware network resources even applications digital identity entity online presence encompassing personal identifying information pii ancillary information see oecd nist guidelines protecting pii interpreted codification identity names attributes physical instance way facilitates processing real-world context engineering online systems identity management involve four basic functions general model identity constructed small set axioms example identities given namespace unique identities bear specific relationship corresponding entities real world axiomatic model expresses pure identity sense model constrained specific application context general entity real virtual multiple identities identity encompass multiple attributes unique within given name space diagram illustrates conceptual relationship identities entities well identities attributes theoretical practical models digital identity given identity object consists finite set properties attribute values properties record information object either purposes external model operate model example classification retrieval pure identity model strictly concerned external semantics properties common departure pure identity practice occurs properties intended assure aspect identity example digital signature software token model may use internally verify aspect identity satisfaction external purpose extent model expresses semantics internally pure model contrast situation properties might externally used purposes information security managing access entitlement simply stored maintained retrieved without special treatment model absence external semantics within model qualifies pure identity model identity management defined set operations given identity model generally set capabilities reference practice identity management often expands express model contents provisioned reconciled among multiple identity models user access enables users assume specific digital identity across applications enables access controls assigned evaluated identity use single identity given user across multiple systems eases tasks administrators users simplifies access monitoring verification allows organizations minimize excessive privileges granted one user user access tracked initiation termination user access organizations deploy identity management process system motivation normally primarily manage set identities rather grant appropriate access rights entities via identities words access management normally motivation identity management two sets processes consequently closely related organizations continue add services internal users customers many services require identity management properly provide services increasingly identity management partitioned application functions single identity serve many even organization activities internal use identity management evolving control access digital assets including devices network equipment servers portals content applications and/or products services often require access extensive information user including address books preferences entitlements contact information since much information subject privacy and/or confidentiality requirements controlling access vital name implies identity federation comprises one systems federate user access allow users log based authenticating one systems participating federation trust several systems often known circle trust setup one system acts identity provider idp system acts service provider sp user needs access service controlled sp he/she first authenticates idp upon successful authentication idp sends secure assertion service provider saml assertions specified using mark language intended describing security assertions used verifier make statement relying party identity claimant saml assertions may optionally digitally signed addition creation deletion modification user identity data either assisted self-service identity management controls ancillary entity data use applications contact information location putting personal information onto computer networks necessarily raises privacy concerns absent proper protections data may used implement surveillance society social web online social networking services make heavy use identity management helping users decide manage access personal information become issue broad concern identity theft happens thieves gain access identity information personal details needed get access bank account research related management identity covers disciplines technology social sciences humanities law within seventh research framework programme european union 2007 2013 several new projects related identity management started picos project investigates develops state-of-the-art platform providing trust privacy identity management mobile communities primelife develops concepts technologies help individuals protect autonomy retain control personal information irrespective activities swift focuses extending identity functions federation network addressing usability privacy concerns leverages identity technology key integrate service transport infrastructures benefit users providers ongoing projects include future identity information society fidis guide prime academic journals publish articles related identity management include less specialized journals publish topic instance special issues identity iso specifically iso/iec jtc1 sc27 security techniques wg5 identity access management privacy techniques conducting standardization work identity management elaboration framework identity management including definition identity-related terms published standards current work items includes following organization normally role department responsible managing schema digital identities staff objects represented object identities object identifiers oid
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Computer security
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directory computing computing directory file system cataloging structure contains references computer files possibly directories many computers directories known folders drawers analogous workbench traditional office filing cabinet files organized storing related files directory hierarchical file system one files directories organized manner resembles tree directory contained inside another directory called subdirectory terms parent child often used describe relationship subdirectory directory cataloged latter parent top-most directory filesystem parent called root directory historically even modern embedded systems file systems either support directories flat directory structure meaning subdirectories supported group top-level directories containing files modern systems directory contain mix files subdirectories reference location directory system called path many operating systems programs associated working directory execute typically file names accessed program assumed reside within directory file names specified explicit directory name operating systems restrict user access home directory project directory thus isolating activities users early versions unix root directory home directory root user modern unix usually uses another directory /root purpose keeping unix philosophy unix systems treat directories type file name folder presenting analogy file folder used offices used hierarchical file system design electronic recording machine accounting erma mark 1 published 1958 well xerox star used almost modern operating systems desktop environments folders often depicted icons visually resemble physical file folders difference directory file system concept graphical user interface metaphor used represent folder example microsoft windows uses concept special folders help present contents computer user fairly consistent way frees user deal absolute directory paths vary versions windows individual installations many operating systems also concept smart folders virtual folders reflect results file system search operation folders represent directory file hierarchy many email clients allow creation folders organize email folders corresponding representation filesystem structure one referring container documents term folder appropriate term directory refers way structured list document files folders stored computer distinction due way directory accessed unix systems /usr/bin/ usually referred directory viewed command line console accessed graphical file manager users may sometimes call folder operating systems support hierarchical filesystems practically modern ones implement form caching ram recent path lookups unix world usually called directory name lookup cache dnlc although called dcache linux local filesystems dnlc entries normally expire pressure recent entries network file systems coherence mechanism necessary ensure entries invalidated clients
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Computer file systems
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tõnu samuel tõnu samuel born 3 july 1972 estonian hacker commonly cited mainstream media topics regarding network security samuel born tallinn 1979 1988 attended tallinn secondary science school 1990–1992 took courses business financial management career programmer began 1991 working estonian ministry communication 2011 samuel moved work japan lived 10 years räpina southeastern estonia
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Computer security
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xerox escape sequence xerox escape sequence xes page description language pdl developed xerox corporation introduced 2700 laser printers 1982 xes offers similar capabilities hewlett-packard printer command language pcl first appeared 1984 xes supported xerox laser printers including 2700 3700 4011 4030 4045 4197 4213 4235 4700 xes sometimes known udk user defined key character introduces printer command usually escape character esc
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Programming language topics
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logic bomb logic bomb piece code intentionally inserted software system set malicious function specified conditions met example programmer may hide piece code starts deleting files salary database trigger ever terminated company software inherently malicious viruses worms often contain logic bombs execute certain payload pre-defined time condition met technique used virus worm gain momentum spread noticed viruses attack host systems specific dates friday 13th april fools day trojans computer viruses activate certain dates often called time bombs considered logic bomb payload unwanted unknown user software example trial programs code disables certain functionality set time normally regarded logic bombs reported 1982 trans-siberian pipeline incident occurred logic bomb later reported story may hoax kgb operative reported stolen plans sophisticated control system software canadian firm use siberian pipeline central intelligence agency cia supposedly tipped documents farewell dossier company insert logic bomb program sabotage purposes
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Computer security
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seventh edition unix terminal interface seventh edition unix terminal interface generalized abstraction comprising application programming interface programs set behavioural expectations users terminal historically available seventh edition unix largely superseded posix terminal interface terminal interface provided seventh edition unix unix/32v also presented bsd version 4 old terminal driver simple one largely geared towards teletypewriters terminals input entered line time terminal driver operating system terminals providing simple line editing capabilities buffer maintained kernel editing took place applications reading terminal input would receive contents buffer key pressed terminal end line editing key sent terminal system would erase kill entire current contents editing buffer would normally displayed symbol followed newline sequence move print position fresh blank line key sent terminal system would erase last character end editing buffer would normally displayed symbol users would recognize denoting rubout preceding character teletypewriters physically capable erasing characters printed paper programming point view terminal device transmit receive baud rates erase kill characters performed line editing explained interrupt quit characters generating signals processes terminal controlling terminal start stop characters used software flow control end file character acting like carriage return except discarded buffer codice_1 system call therefore potentially causing zero-length result returned various mode flags determining whether local echo emulated kernel terminal driver whether modem flow control enabled lengths various output delays mapping carriage return character three input modes three input modes terminals seventh edition unix posix terminal interface modes superseded system two input modes canonical non-canonical handling signal-generating special characters posix terminal interface independent input mode separately controllable seventh edition unix terminal job control process group considered considered nowadays process system either single controlling terminal controlling terminal process inherits controlling terminal parent controlling terminal acquired process controlling terminal codice_2s terminal device file n't already controlling terminal process processes controlling terminal part single process group programmatic interface querying modifying modes control characters codice_3 system call replaced codice_4 codice_5 system calls sixth edition unix although erase kill characters modifiable defaults many years seventh edition development inertia meant pre-set defaults terminal device drivers many unix systems altered terminal device settings part login process system login scripts ran user entered username password mistakes login password prompts corrected using historical editing key characters inherited teletypewriter terminals symbolic constants whose values fixed defined data structure definitions programmatic interface defined codice_6 system header codice_3 operations follows one data structure used terminal system calls codice_9 structure whose c programming language definition follows unlike posix terminal interface seventh edition unix terminal interface recorded input output baud rates directly data structure input output speeds codice_11 codice_12 fields dec dh-11 numbers 0 15 represented symbolic constants ascending order codice_13 codice_14 codice_15 codice_16 codice_17 codice_18 codice_19 codice_20 codice_21 codice_22 codice_23 codice_24 codice_25 codice_26 codice_27 codice_28 baud rate name last two external external b setting baud rate zero forced terminal driver hang modem terminal modem device codice_29 codice_30 fields simply character values erase kill characters respectively defaulting ascii values respectively codice_31 field specified various input output control flags following table one data structure used terminal system calls codice_32 structure whose c programming language definition follows values fields values various programmatically configurable special characters -1 value field disabled recognition terminal driver
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Operating systems
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microsoft venus microsoft venus aborted venture microsoft low-end personal computing market people republic china product set-top operating system designed work low-end televisions somewhat similar msn tv united states announced then-microsoft chairman bill gates march 10 1999 shenzhen made available january 2000 never made microsoft lab however slowly dying less year announcement relatively little known microsoft venus since project never made beyond prototype stage designed exclusive people republic china known project appears show microsoft designed venus response largely untapped chinese computing market low-end set-top box designed combination internet accessibility basic features personal computer rudimentary word processor hoped tap market gaining market share profit world fastest-growing economy process despite initial support chinese government — included limited discounts assorted subsidies — lucrative distribution agreements acer philips lenovo companies planned venture faced many problems largest massive cost overrun units reported sell 3,000 yuan us 360 time large sum general chinese public 1999 progressed 2000 began chinese government relations microsoft continued sour production costs venus tension reached fever pitch january 2000 chinese government ordered windows 2000 uninstalled ministerial computers opting use locally produced red flag linux instead january 2000 passed without venus release product remained vaporware microsoft aforementioned brief showdown chinese government month talk venus appears ceased news media venus never released went microsoft attempt selling low-cost computing chinese masses microsoft first attempt bringing computing chinese masses failure later events proved favorable company lenovo purchase ibm windows-based computing division 2005 gave consumer electronics corporation partially owned chinese government strong presence windows computing market home china abroad persisted since initial acquisition however lenovo computers full-fledged pcs bear strong resemblance all-in-one television component microsoft envisioned becoming large success china according reuters account initial unveiling venus prototype box intended combine internet browser rudimentary word processing graphic design suite cd player one set-top television component gates touted computer learning capabilities ability intended combined contract forty chinese governmental ministries produce application known government online would served stated purpose bringing chinese bureaucracy closer masses microsoft reportedly intended venus boxes run special version windows ce fine-tuned display television sets exact processor speeds never released microsoft believed comparable low-end windows computers time
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Operating systems
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cerias center education research information assurance security cerias purdue university united states center research education areas information security computing communication infrastructures research focused following areas cerias one world ’ leading academic institutions area one nsf original seven centers academic excellence information assurance education cerias rooted coast research group computer operations audit security technology established 1991 computer sciences department purdue research groups professors eugene spafford samuel wagstaff jr.. coast initially funded sun microsystems schlumberger bell northern research bnr nortel hughes research laboratories coast subsumed cerias january 1 1999
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Computer security
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edsger w. dijkstra edsger wybe dijkstra 11 may 1930 – 6 august 2002 dutch systems scientist programmer software engineer science essayist pioneer computing science theoretical physicist training worked programmer mathematisch centrum amsterdam 1952 1962 university professor much life dijkstra held schlumberger centennial chair computer sciences university texas austin 1984 retirement 1999 professor mathematics eindhoven university technology 1962–1984 research fellow burroughs corporation 1973–1984 one influential figures computing science founding generation dijkstra helped shape new discipline engineering theoretical perspective fundamental contributions cover diverse areas computing science including compiler construction operating systems distributed systems sequential concurrent programming programming paradigm methodology programming language research program design program development program verification software engineering principles graph algorithms philosophical foundations computer programming computer science many papers source new research areas several concepts problems standard computer science first identified dijkstra bear names coined foremost opponent mechanizing view computing science refuted use concepts 'computer science 'software engineering umbrella terms academic disciplines mid-1960s computer programming considered art craft scientific discipline harlan mills words 1986 programming 1970s regarded private puzzle-solving activity writing computer instructions work program late 1960s computer programming state crisis dijkstra one small group academics industrial programmers advocated new programming style improve quality programs dijkstra background mathematics physics one driving forces behind acceptance computer programming scientific discipline coined phrase structured programming 1970s became new programming orthodoxy ideas structured programming helped lay foundations birth development professional discipline software engineering enabling programmers organize manage increasingly complex software projects bertrand meyer 2009 noted revolution views programming started dijkstra iconoclasm led movement known structured programming advocated systematic rational approach program construction structured programming basis done since programming methodology including object-oriented programming academic study concurrent computing started 1960s dijkstra 1965 credited first paper field identifying solving mutual exclusion problem also one early pioneers research principles distributed computing foundational work concurrency semaphores mutual exclusion deadlock deadly embrace finding shortest paths graphs fault-tolerance self-stabilization among many contributions comprises many pillars upon field distributed computing built shortly death 2002 received acm podc influential-paper award distributed computing work self-stabilization program computation annual award renamed dijkstra prize edsger w. dijkstra prize distributed computing following year honor prize sponsored jointly acm symposium principles distributed computing podc eatcs international symposium distributed computing disc recognizes individual larger influence research principles distributed computing edsger w. dijkstra born rotterdam father chemist president dutch chemical society taught chemistry secondary school later superintendent mother mathematician never formal job dijkstra considered career law hoped represent netherlands united nations however graduating school 1948 parents suggestion studied mathematics physics theoretical physics university leiden early 1950s electronic computers novelty dijkstra stumbled career quite accident supervisor professor a. haantjes met adriaan van wijngaarden director computation department mathematical center amsterdam offered dijkstra job officially became netherlands first programmer march 1952 time dijkstra remained committed physics working leiden three days week increasing exposure computing however focus began shift recalled dijkstra married maria ria c. debets 1957 required part marriage rites state profession stated programmer unacceptable authorities profession time netherlands 1959 received phd university amsterdam thesis entitled 'communication automatic computer devoted description assembly language designed first commercial computer developed netherlands x1 thesis supervisor van wijngaarden 1952 1962 dijkstra worked mathematisch centrum amsterdam worked closely bram jan loopstra carel s. scholten hired build computer mode interaction disciplined would first decide upon interface hardware software writing programming manual hardware designers would faithful part contract dijkstra programmer would write software nonexistent machine two lessons learned experience importance clear documentation program debugging largely avoided careful design dijkstra formulated solved shortest path problem demonstration official inauguration armac computer 1956 but—because absence journals dedicated automatic computing—did publish result 1959 mathematical center dijkstra colleague developed compiler programming language algol 60 profound influence later thinking programming scientific activity zonneveld completed implementation first algol 60 compiler august 1960 year compiler produced another group 1962 dijkstra moved eindhoven later nuenen south netherlands became professor mathematics department eindhoven university technology university separate computer science department culture mathematics department particularly suit dijkstra tried build group computer scientists could collaborate solving problems unusual model research mathematics department late 1960s built operating system named university known technische hogeschool eindhoven influenced designs subsequent operating systems use software based paged virtual memory dijkstra joined burroughs corporation company known time production computers based innovative hardware architecture research fellow august 1973 duties consisted visiting company research centers times year carrying research smallest burroughs research facility namely study second floor house nuenen fact dijkstra research fellow burroughs corporation worked home occasionally travelling branches united states result reduced appointment university one day week day tuesday soon became known day famous 'tuesday afternoon club seminar discussed colleagues scientific articles looking aspects – notation organisation presentation language content etc shortly moved 1984 university texas austin usa new 'branch tuesday afternoon club emerged austin burroughs years saw prolific output research articles wrote nearly 500 documents ewd series described technical reports private circulation within select group dijkstra accepted schlumberger centennial chair computer science department university texas austin 1984 dijkstra worked austin retirement november 1999 mark occasion celebrate forty-plus years seminal contributions computing science department computer sciences organized symposium took place 70th birthday may 2000 dijkstra wife returned austin original house nuenen netherlands found months live said wanted retire austin texas die netherlands dijkstra died 6 august 2002 long struggle cancer wife maria ria debets survived three children marcus femke computer scientist rutger m. dijkstra early theoretical pioneer many research areas computing science dijkstra helped shape new discipline engineering academic perspective many papers source new research areas many concepts standard computer science first identified dijkstra and/or bear names coined several important problems also first formulated solved 1994 survey thousand professors computer science conducted obtain list 38 influential scholarly papers field dijkstra author five papers forty-plus years computing scientist included positions academia industry dijkstra made numerous seminal contributions many areas computing science including compiler construction operating systems concurrent programming concurrent computing distributed programming distributed computing programming paradigm methodology programming language research program design program development program verification software engineering principles algorithm design philosophical foundations computer programming computer science addition dijkstra intensely interested teaching computer science relationships academic computing science software industry dijkstra algorithmic work especially graph algorithms concurrent algorithms distributed algorithms plays important role many areas computing science according leslie lamport 2002 dijkstra started field concurrent distributed algorithms 1965 cacm paper solution problem concurrent programming control first stated solved mutual exclusion problem lamport explains paper probably podc exists ... remains day influential paper field win podc influential paper award reflects artificial separation concurrent distributed algorithms–a separation never existed dijkstra work 1959 dijkstra published 3-page article note two problems connexion graphs algorithm find shortest path graph two given nodes called dijkstra algorithm impact next 40 years summarised article mikkel thorup 'undirected single source shortest paths positive integer weights linear time 1999 since 1959 theoretical developments sssp single-source shortest paths general directed undirected graphs based dijkstra algorithm dijkstra algorithm used spf shortest path first used routing protocols ospf is-is various modifications dijkstra algorithm proposed many authors using heuristics reduce run time shortest path search one used heuristic algorithms a* search algorithm first described peter hart nils nilsson bertram raphael stanford research institute 1968 main goal reduce run time reducing search space dijkstra thought shortest path problem working mathematical center amsterdam 1956 programmer demonstrate capabilities new computer called armac objective choose problem well answer would produced computer non-computing people could understand designed shortest path algorithm 20 minutes without aid paper pen later implemented armac slightly simplified transportation map 64 cities netherlands 6 bits would suffice represent city algorithm recalled interview published 2001 year later came across another problem hardware engineers working institute next computer minimize amount wire needed connect pins back panel machine solution re-discovered algorithm known prim minimal spanning tree algorithm prim algorithm originally developed 1930 czech mathematician vojtěch jarník later independently rediscovered republished robert c. prim 1957 dijkstra 1959 therefore also sometimes called djp algorithm 1961 dijkstra first described shunting-yard algorithm method parsing mathematical expressions specified infix notation mathematisch centrum report used produce output reverse polish notation rpn abstract syntax tree ast algorithm named shunting yard algorithm operation resembles railroad shunting yard shunting-yard algorithm commonly used implement operator-precedence parsers 1962 1963 dijkstra proposed semaphore mechanism mutual exclusion algorithm n processes generalization dekker algorithm probably first published concurrent algorithm introduced new area algorithmic research also identified deadlock problem proposed banker algorithm prevents deadlock 1974 dijkstra presented three self-stabilizing algorithms mutual exclusion ring dijkstra work considered first introduce demonstrate self-stabilization concept mid-1970s dijkstra together authors introduced two useful abstractions mutator collector study garbage collection mutator abstracts process performs computation including allocation new storage cell collector process automatically reclaims garbage furthermore paper gives formalization tri-color marking basic incremental garbage collection early 1980s dijkstra carel s. scholten proposed dijkstra–scholten algorithm detecting termination distributed systems 1981 dijkstra developed smoothsort comparison-based sorting algorithm variation heapsort dijkstra known fan algol 60 worked team implemented first compiler language closely involved algol 60 development realisation popularisation discussed peter naur article 'the european side last phase development algol 60 proceedings first acm sigplan conference history programming languages january 1978 dijkstra took part period 1958–1959 number meetings culminated publication report defining algol 60 language dijkstra name appear list 13 authors final report apparently eventually left committee could agree majority opinions still mathematisch centrum amsterdam wrote jointly jaap zonneveld first algol 60 compiler dijkstra zonneveld collaborated compiler agreed shave project completed zonneveld shaved shortly thereafter dijkstra kept beard rest life algol result collaboration american european committees algol 60 short algorithmic language 1960 member algol family computer programming languages followed algol 58 inspired many languages followed gave rise many programming languages including bcpl b pascal simula c. algol 60 sophisticatedly designed computer language provided large number hitherto unknown implementation challenges bjarne stroustrup notes one problem algol60 one knew implement major new challenge algol 60 implementation run-time allocation management data 1960 dijkstra zonneveld showed recursive procedures could executed using run-time stack activation records efficiently access identifiers statically enclosing scopes using so-called 'display algol 60 compiler one first support recursion employing novel method dijkstra short book primer algol 60 programming originally published 1962 standard reference language several years computer programming 1950s 1960s recognized academic discipline unlike mature sciences theoretical concepts coding systems programming professional activity poorly understood years late 1960s computer programming state crisis software crisis term used early days computing science difficulty writing useful efficient computer programs required time software crisis due rapid increases computer power complexity problems could tackled increase complexity software many software problems arose existing methods insufficient term software crisis coined attendees first nato software engineering conference 1968 garmisch germany 1972 acm turing award lecture makes reference problem major cause software crisis machines become several orders magnitude powerful put quite bluntly long machines programming problem weak computers programming became mild problem gigantic computers programming become equally gigantic problem dijkstra programmed extensively machine code 1950s came conclusion high-level languages frequent use goto statement usually symptomatic poor structure 1968 wrote private paper case go statement published letter cacm editor niklaus wirth gave letter heading go statement considered harmful introduced phrase considered harmful computing dijkstra argued programming statement goto found many high-level programming languages major source errors therefore eliminated letter caused huge debate programming community went length equating good programming elimination go dijkstra refused mention debate even go statement article notes structured programming debate long since died programming languages provide alternatives go programmers today use liberally never use dijkstra thesis departures linear control flow clearer allowed disciplined higher-level structures if-then-else statement loop methodology developed structured programming movement title 1972 book coauthored c.a.r hoare ole-johan dahl considered many first significant movement history computer programming structured programming became new programming orthodoxy 1970s bertrand meyer remarked revolution views programming started dijkstra iconoclasm led movement known structured programming advocated systematic rational approach program construction structured programming basis done since programming methodology including object-oriented programming structured programming often regarded goto-less programming bertrand meyer notes first book topic structured programming dijkstra dahl hoare shows structured programming much control structures goto principal message programming considered scientific discipline based mathematical rigor structured programming – especially 1970s 1980s – significantly influenced birth many modern programming languages pascal c modula-2 ada fortran 77 version incorporates concepts structured programming released 1978 c++ language considerably extended enhanced version popular c see also list c-based programming languages since c++ developed traditional 'hybrid language rather pure object-oriented programming language article structured programming retrospect prospect 1986 harlan mills writes edsger w. dijkstra 1969 structured programming article precipitated decade intense focus programming techniques fundamentally altered human expectations achievements software development decade intense focus programming regarded private puzzle-solving activity writing computer instructions work program decade programming could regarded public mathematics-based activity restructuring specifications programs challenge getting programs run getting debugged right things programs could expected run right things little debugging common wisdom sizable program could error-free many sizable programs run year errors detected expectations achievements universal inertia industrial practices well-enough established herald fundamental change software development book concise encyclopedia computer science 2004 edited edwin d. reilly notes major contributions structured programming twofold—the elevation programming technique something less art science demonstration carefully structured programs creative works sufficient literary merit deserve read humans computer dijkstra ideas programming methodology especially structured programming movement helped lay foundations birth development professional discipline software engineering particular software design development enabling programmers organize manage increasingly complex software projects late 1960s dijkstra discussed concept program families mid 1970s david parnas others clarified idea showed apply software engineering principles rise structured programming movement led many structured approaches applied software design techniques structured analysis structured design outgrowths structured programming concepts techniques early ideas modular design principles modularity strengthened larry constantine concepts coupling minimized modules cohesion maximized within modules david parnas techniques information hiding abstract data types number tools methods employing structured concepts developed structured design jackson structured programming ross structured analysis design technique sadt yourdon structured method structured systems analysis design method ssadm james martin information technology engineering field software metrics often considered direct influence structured programming movement software engineering 1970s separation concerns soc one basic principles software engineering design principle separating computer program distinct sections section addresses separate concern term separation concerns coined dijkstra 1974 paper role scientific thought 1960s dijkstra colleagues eindhoven designed implemented standing 'technische hogeschool eindhoven operating system organised clearly identified layers 1968 article subject provided foundation subsequent designs operating systems ieee computer society david alan grier writes generally trace idea building computer systems layers back 1967 paper dutch computer scientist edsger dijkstra gave joint ieee computer society/acm conference prior paper engineers struggled problem organize software look early examples programs find many electronic library computer society find code era complicated difficult read hard modify challenging reuse 1967 paper dijkstra described software could constructed layers gave example simple operating system used five layers admitted system might realistic test ideas argued larger project essential structuring idea using layers control complexity become mainstay software architecture see many forms apply many problems see hierarchy classes object-oriented programming structure service-oriented architecture soa soa relatively recent application layering computer science articulated 2007 means controlling complexity business systems especially distributed systems make substantial use internet like dijkstra plan system development layering system called soa solution stack s3 s3 nine layers 1 operational systems 2 service components 3 services 4 business processes 5 consumer actions 6 system integration 7 quality control assurance 8 information architecture 9 system governance policies dijkstra organized design system layers order reduce overall complexity software though term 'architecture yet used describe software design certainly considered first glimpse software architecture introduced number design principles become part working vocabulary every professional programmer levels abstraction programming layers semaphore cooperating sequential processes original paper operating system reprinted 25th anniversary issue communications acm january 1983 way introduction editor-in-chief says project initiated long line research multilevel systems architecture — line continues present day hierarchical modularity powerful approach organizing large systems one-page paper 1965 dijkstra introduced 'mutual exclusion problem n processes discussed solution probably first published concurrent algorithm notion standard 'critical section also introduced paper per brinch hansen pioneer field concurrent computing considers dijkstra cooperating sequential processes 1965 first classic paper concurrent programming brinch hansen notes 'dijkstra lays conceptual foundation abstract concurrent programming paper 1968 dijkstra published seminal paper 'cooperating sequential processes 70-page essay originated field concurrent programming discussed notion mutual exclusion mutex criteria satisfactory solution satisfy also redressed historical perspective left 1965 paper including first known correct solution mutual exclusion problem two processes due theodorus dekker dijkstra subsequently generalized dekker solution n processes proposed first synchronisation mechanism concurrent processes semaphore two operations p v. also identified 'deadlock problem called 'the problem deadly embrace proposed elegant 'banker algorithm prevents deadlock deadlock detection prevention became perennial research problems field concurrent programming dining philosophers problem example problem often used concurrent algorithm design illustrate synchronization issues techniques resolving originally formulated 1965 dijkstra student exam exercise presented terms computers competing access tape drive peripherals soon tony hoare gave problem present formulation sleeping barber problem also attributed dijkstra book concurrent programming algorithms principles foundations michel raynal writes since early work e.w dijkstra 1965 introduced mutual exclusion problem concept process semaphore object notion weakest precondition guarded commands among many contributions synchronization longer catalog tricks domain computing science concepts mechanisms techniques whose results applied many domains means process synchronization major topic computer science curriculum john w. mccormick et al 2011 notes notion concurrent program means writing parallel programs without regard underlying hardware first introduced edsger dijkstra 1968 moti ben-ari 1982 elegantly summed dijkstra idea three sentences ‘ concurrent programming name given programming notation techniques expressing potential parallelism solving resulting synchronization communication problems implementation parallelism topic computer systems hardware software essentially independent concurrent programming concurrent programming important provides abstract setting study parallelism without getting bogged implementation details. ’ dijkstra one early pioneers research principles distributed computing citation dijkstra prize recognizes individual larger influence research principles distributed computing papers even considered established field dijkstra 1965 paper solution problem concurrent programming control first present correct solution mutual exclusion problem leslie lamport writes work probably podc exists started field concurrent distributed algorithms particular paper self-stabilizing systems spite distributed control 1974 started sub-field self-stabilization also considered first scientific examination fault-tolerant systems dijkstra paper widely noticed leslie lamport invited talk acm symposium principles distributed computing podc 1983 report dijkstra work self-stabilizing distributed systems lamport regard milestone work fault tolerance fertile field research 1970s dijkstra chief interest formal verification 1976 dijkstra published seminal book discipline programming put forward method systematic development programs together correctness proofs exposition used 'guarded command language language reliance non-determinism adopted weakest precondition semantics proposed development method considerable impact field day refinement calculus originally proposed ralph-johan back developed carroll morgan extension dijkstra weakest precondition calculus program statements modeled predicate transformers 1984 add support approach programming published jointly wim feijen introductory textbook first-year students computer science book first published dutch entitled een methode van programmeren english edition appeared 1988 method programming many opinions computer science programming become widespread example programming phrase two use rule thumb use loop sometimes attributed first make claim programming inherently complex order manage successfully programmers need harness every trick abstraction possible dijkstra one famous opponents engineering view computing science like peter naur kristen nygaard dijkstra disliked term 'computer science computer science dijkstra pointed deserves better name suggests called 'computing science instead computer computing technology dijkstra wanted emphasize abstract mechanisms computing science uses master complexity expressing abstract nature computing science wrote humble programmer 1972 dijkstra wrote must forget computing scientists business make programs business design classes computations display desired behaviour dijkstra also opposed inclusion software engineering umbrella academic computer science wrote economics known miserable science software engineering known doomed discipline doomed even approach goal since goal self-contradictory software engineering accepted charter program world computing science dijkstra well known character preface book discipline programming 1976 stated following absence bibliography offer neither explanation apology fact articles books references approach references deplored researchers dijkstra chose way working preserve self-reliance university professor much life dijkstra saw teaching required activity serious research endeavor approach teaching unconventional lecturing style described idiosyncratic lecturing long pauses sentences often attributed fact english dijkstra first language however pauses also served way think feet regarded quick deep thinker engaged act lecturing courses students austin little computer science dealt presentation mathematical proofs beginning semester would take photo students order memorize names never followed textbook possible exception preparation lecturing would write proofs chalk blackboard rather using overhead foils invited students suggest ideas explored refused explore violated tenets assigned challenging homework problems would study students solutions thoroughly conducted final examinations orally whole week student examined dijkstra office home exam lasted several hours also highly original way assessing people capacity job vladimir lifschitz came austin 1990 job interview dijkstra gave puzzle vladimir solved working austin since despite invented much technology software dijkstra eschewed use computers work many decades even succumbed ut colleagues encouragement acquired macintosh computer used e-mail browsing world wide web dijkstra never wrote articles using computer preferred rely typewriter later montblanc pen dijkstra favorite writing instrument montblanc meisterstück fountain pen repeatedly tried pens none ever displaced montblanc use word processors believing one able write letter article without rough drafts rewriting significant editing would work head putting pen paper mentioned physics student would solve homework problems head walking streets leiden dijkstra publications written alone never secretary took care correspondence alone colleagues prepared festschrift sixtieth birthday published springer-verlag took trouble thank 61 contributors separately hand-written letter throughout dijkstra career work characterized elegance economy prolific writer especially essayist dijkstra authored 1,300 papers many written hand precise script essays parables fairy tales warnings comprehensive explanation pedagogical pretext mathematics computer science others trip reports revealing author people places visited habit copy paper circulate small group colleagues would copy forward papers another limited group scientists love affair simplicity came early age mother guidance said asked mother whether trigonometry difficult topic replied must learn formulas furthermore required five lines prove something wrong track dijkstra famous wit eloquence rudeness abruptness often cruelty fellow professionals way words remark question whether machines think … relevant question whether submarines swim advice promising researcher asked select topic research dijkstra also known vocal criticism absence social skills interacting colleagues outspoken critical visionary strongly opposed teaching basic many humorous essays dijkstra described fictional company served chairman company called mathematics inc. company imagined commercialized production mathematical theorems way software companies commercialized production computer programs invented number activities challenges mathematics inc. documented several papers ewd series imaginary company produced proof riemann hypothesis great difficulties collecting royalties mathematicians proved results assuming riemann hypothesis proof trade secret many company proofs rushed door much company effort spent maintenance successful effort standard proof pythagoras theorem replaced 100 incompatible existing proofs dijkstra described mathematics inc. exciting miserable business ever conceived ewd 443 1974 describes fictional company 75 percent world market share dijkstra well known habit carefully composing manuscripts fountain pen manuscripts called ewds since dijkstra numbered ewd initials prefix according dijkstra ewds started moved mathematical centre amsterdam eindhoven university technology technische hogeschool eindhoven going eindhoven dijkstra experienced writer block year dijkstra distributed photocopies new ewd among colleagues many recipients photocopied forwarded copies ewds spread throughout international computer science community topics computer science mathematics included trip reports letters speeches short articles span period 40 years almost ewds appearing 1972 hand-written rarely longer 15 pages consecutively numbered last one 1318 14 april 2002 within computer science known ewd reports simply ewds 1300 ewds scanned growing number transcribed facilitate search available online dijkstra archive university texas dijkstra self-confidence went together remarkably modest lifestyle point spartan wife house nuenen simple small unassuming tv vcr mobile telephone go movies contrast played piano well austin liked go concerts enthusiastic listener classical music dijkstra favorite composer mozart dijkstra died 6 august 2002 according officials university texas cause death cancer 1972 association computing machinery acm acknowledged dijkstra seminal contributions field awarding distinguished turing award citation award reads introduction given awards ceremony tribute dijkstra words sir tony hoare frs delivered dijkstra funeral march 2003 following email sent distributed computing community former acm president peter j. denning wrote dijkstra among dijkstra awards honors distinguished fellowship british computer society bcs awarded bylaw 7 bcs royal charter award first approved 1969 first election made 1971 dijkstra occasion dijkstra 60th birthday 1990 department computer science utcs university texas austin organized two-day seminar honor speakers came united states europe group computer scientists contributed research articles edited book 2002 c c foundation japan recognized dijkstra pioneering contributions establishment scientific basis computer software creative research basic software theory algorithm theory structured programming semaphores dijkstra alive receive notice award accepted family award ceremony death shortly death 2002 dijkstra received acm podc influential-paper award distributed computing work self-stabilization program computation annual award renamed dijkstra prize edsger w. dijkstra prize distributed computing following year honor dijkstra award outstanding academic achievement computer science loyola university chicago department computer science named edsger w. dijkstra beginning 2005 award recognizes top academic performance graduating computer science major selection based gpa major courses election department faculty department computer science utcs university texas austin hosted inaugural edsger w. dijkstra memorial lecture 12 october 2010 tony hoare emeritus professor oxford principal researcher microsoft research speaker event lecture series made possible generous grant schlumberger honor memory dijkstra
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Programming language topics
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thermal head thermal head component metrological device created aid development new cpus chipsets first thermal head constructed 1996 james kerner initially designed control slot 1 intel processor temperature making computations test platform thermal head attached cpu may also increase cpu performance computation today used test/validation processor conjunction thermal management system consisting temperature controller attached thermal head way electrical umbilical thermal head always used conjunction thermal tool system among ustc thermal tool system products integrated thermal management system itms hybrid air thermal management system hatms rack integrated thermal management system ritms temperature control system tcs thermal heads th integrating cooling modules tcs one enclosure liquid working fluid combined th itms executes temperature control tasks without components using air cooling media hatms executes tasks like itms ritms includes smart tcs unit automatically adjusts parameters temperature control ultra-low noise level low power consumption tcs standard temperature control unit th dissipate heat heat-generated device like computer ritms tcs combined chiller heat exchanger th provide standard way control temperature dissipate heat electronic components production validation tests
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Computer architecture
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zerto zerto ltd. main product zerto virtual replication provides business continuity software virtualized infrastructure cloud environments zerto headquartered israel ziv kedem zerto founder ceo previously co-founded kashya zerto received investments venture capital firms 83north formerly greylock il battery ventures harmony partners rtp ventures ivp usvp 2016 company ranked 45 deloitte fast 500 north america list 10 august 2017 emc corporation awarded ongoing royalties payable zerto connection 4 patents zerto provides disaster recovery software virtualized cloud infrastructures company main product zerto virtual replication released august 2011 technology leverages 'hypervisor-based replication moves data replication server stack storage layer hypervisor zerto entirely hypervisor storage-agnostic data replicated vm operating different platform zvr initially support microsoft azure
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Computer security
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physical access physical access term computer security refers ability people physically gain access computer system according gregory white given physical access office knowledgeable attacker quickly able find information needed gain access organization computer systems network physical access opens variety avenues hacking michael meyers notes best network software security measures rendered useless fail physically protect systems since intruder could simply walk server crack password leisure physical access also allows hardware keyloggers installed intruder may able boot cd external media read unencrypted data hard drive may also exploit lack access control boot loader instance pressing f8 certain versions microsoft windows booting specifying 'init=/bin/sh boot parameter linux usually done editing command line grub etc one could also use rogue device access poorly secured wireless network signal sufficiently strong one might even need breach perimeter security standards united states typically call physical access limited locked server rooms sign-in sheets etc physical access systems security systems historically administered separate departments organizations increasingly seen interdependent functions needing single converged security policy department could instance check security log entries suspicious logons occurring business hours use keycard swipe records building access control system narrow list suspects building time surveillance cameras might also used deter detect unauthorized access
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Computer security
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speech synthesis speech synthesis artificial production human speech computer system used purpose called speech computer speech synthesizer implemented software hardware products text-to-speech tts system converts normal language text speech systems render symbolic linguistic representations like phonetic transcriptions speech synthesized speech created concatenating pieces recorded speech stored database systems differ size stored speech units system stores phones diphones provides largest output range may lack clarity specific usage domains storage entire words sentences allows high-quality output alternatively synthesizer incorporate model vocal tract human voice characteristics create completely synthetic voice output quality speech synthesizer judged similarity human voice ability understood clearly intelligible text-to-speech program allows people visual impairments reading disabilities listen written words home computer many computer operating systems included speech synthesizers since early 1990s text-to-speech system engine composed two parts front-end back-end front-end two major tasks first converts raw text containing symbols like numbers abbreviations equivalent written-out words process often called text normalization pre-processing tokenization front-end assigns phonetic transcriptions word divides marks text prosodic units like phrases clauses sentences process assigning phonetic transcriptions words called text-to-phoneme grapheme-to-phoneme conversion phonetic transcriptions prosody information together make symbolic linguistic representation output front-end back-end—often referred synthesizer —then converts symbolic linguistic representation sound certain systems part includes computation target prosody pitch contour phoneme durations imposed output speech long invention electronic signal processing people tried build machines emulate human speech early legends existence brazen heads involved pope silvester ii d. 1003 ad albertus magnus 1198–1280 roger bacon 1214–1294 1779 german-danish scientist christian gottlieb kratzenstein first prize competition announced russian imperial academy sciences arts models built human vocal tract could produce five long vowel sounds notation followed bellows-operated acoustic-mechanical speech machine wolfgang von kempelen pressburg hungary described 1791 paper machine added models tongue lips enabling produce consonants well vowels 1837 charles wheatstone produced speaking machine based von kempelen design 1846 joseph faber exhibited euphonia 1923 paget resurrected wheatstone design 1930s bell labs developed vocoder automatically analyzed speech fundamental tones resonances work vocoder homer dudley developed keyboard-operated voice-synthesizer called voder voice demonstrator exhibited 1939 new york world fair dr. franklin s. cooper colleagues haskins laboratories built pattern playback late 1940s completed 1950 several different versions hardware device one currently survives machine converts pictures acoustic patterns speech form spectrogram back sound using device alvin liberman colleagues discovered acoustic cues perception phonetic segments consonants vowels first computer-based speech-synthesis systems originated late 1950s noriko umeda et al developed first general english text-to-speech system 1968 electrotechnical laboratory japan 1961 physicist john larry kelly jr colleague louis gerstman used ibm 704 computer synthesize speech event among prominent history bell labs kelly voice recorder synthesizer vocoder recreated song daisy bell musical accompaniment max mathews coincidentally arthur c. clarke visiting friend colleague john pierce bell labs murray hill facility clarke impressed demonstration used climactic scene screenplay novel hal 9000 computer sings song astronaut dave bowman puts sleep despite success purely electronic speech synthesis research mechanical speech-synthesizers continues linear predictive coding lpc form speech coding began development work fumitada itakura nagoya university shuzo saito nippon telegraph telephone ntt 1966 developments lpc technology made bishnu s. atal manfred r. schroeder bell labs 1970s lpc later basis early speech synthesizer chips texas instruments lpc speech chips used speak spell toys 1978 1975 fumitada itakura developed line spectral pairs lsp method high-compression speech coding ntt 1975 1981 itakura studied problems speech analysis synthesis based lsp method 1980 team developed lsp-based speech synthesizer chip lsp important technology speech synthesis coding 1990s adopted almost international speech coding standards essential component contributing enhancement digital speech communication mobile channels internet 1975 musa released one first speech synthesis systems consisted stand-alone computer hardware specialized software enabled read italian second version released 1978 also able sing italian cappella style dominant systems 1980s 1990s dectalk system based largely work dennis klatt mit bell labs system latter one first multilingual language-independent systems making extensive use natural language processing methods handheld electronics featuring speech synthesis began emerging 1970s one first telesensory systems inc. tsi speech+ portable calculator blind 1976 devices primarily educational purposes speak spell toy produced texas instruments 1978 fidelity released speaking version electronic chess computer 1979 first video game feature speech synthesis 1980 shoot 'em arcade game stratovox known japan speak rescue sun electronics first personal computer game speech synthesis manbiki shoujo shoplifting girl released 1980 pet 2001 game developer hiroshi suzuki developed zero cross programming technique produce synthesized speech waveform another early example arcade version berzerk also dates 1980 milton bradley company produced first multi-player electronic game using voice synthesis milton year early electronic speech-synthesizers sounded robotic often barely intelligible quality synthesized speech steadily improved output contemporary speech synthesis systems remains clearly distinguishable actual human speech kurzweil predicted 2005 cost-performance ratio caused speech synthesizers become cheaper accessible people would benefit use text-to-speech programs important qualities speech synthesis system naturalness intelligibility naturalness describes closely output sounds like human speech intelligibility ease output understood ideal speech synthesizer natural intelligible speech synthesis systems usually try maximize characteristics two primary technologies generating synthetic speech waveforms concatenative synthesis formant synthesis technology strengths weaknesses intended uses synthesis system typically determine approach used concatenative synthesis based concatenation stringing together segments recorded speech generally concatenative synthesis produces natural-sounding synthesized speech however differences natural variations speech nature automated techniques segmenting waveforms sometimes result audible glitches output three main sub-types concatenative synthesis unit selection synthesis uses large databases recorded speech database creation recorded utterance segmented following individual phones diphones half-phones syllables morphemes words phrases sentences typically division segments done using specially modified speech recognizer set forced alignment mode manual correction afterward using visual representations waveform spectrogram index units speech database created based segmentation acoustic parameters like fundamental frequency pitch duration position syllable neighboring phones run time desired target utterance created determining best chain candidate units database unit selection process typically achieved using specially weighted decision tree unit selection provides greatest naturalness applies small amount digital signal processing dsp recorded speech dsp often makes recorded speech sound less natural although systems use small amount signal processing point concatenation smooth waveform output best unit-selection systems often indistinguishable real human voices especially contexts tts system tuned however maximum naturalness typically require unit-selection speech databases large systems ranging gigabytes recorded data representing dozens hours speech also unit selection algorithms known select segments place results less ideal synthesis e.g minor words become unclear even better choice exists database recently researchers proposed various automated methods detect unnatural segments unit-selection speech synthesis systems diphone synthesis uses minimal speech database containing diphones sound-to-sound transitions occurring language number diphones depends phonotactics language example spanish 800 diphones german 2500 diphone synthesis one example diphone contained speech database runtime target prosody sentence superimposed minimal units means digital signal processing techniques linear predictive coding psola mbrola recent techniques pitch modification source domain using discrete cosine transform diphone synthesis suffers sonic glitches concatenative synthesis robotic-sounding nature formant synthesis advantages either approach small size use commercial applications declining although continues used research number freely available software implementations early example diphone synthesis teaching robot leachim invented michael j. freeman leachim contained information regarding class curricular certain biographical information 40 students programmed teach tested fourth grade classroom bronx new york domain-specific synthesis concatenates prerecorded words phrases create complete utterances used applications variety texts system output limited particular domain like transit schedule announcements weather reports technology simple implement commercial use long time devices like talking clocks calculators level naturalness systems high variety sentence types limited closely match prosody intonation original recordings systems limited words phrases databases general-purpose synthesize combinations words phrases preprogrammed blending words within naturally spoken language however still cause problems unless many variations taken account example non-rhotic dialects english r words like clear usually pronounced following word vowel first letter e.g clear realized likewise french many final consonants become longer silent followed word begins vowel effect called liaison alternation reproduced simple word-concatenation system would require additional complexity context-sensitive formant synthesis use human speech samples runtime instead synthesized speech output created using additive synthesis acoustic model physical modelling synthesis parameters fundamental frequency voicing noise levels varied time create waveform artificial speech method sometimes called rules-based synthesis however many concatenative systems also rules-based components many systems based formant synthesis technology generate artificial robotic-sounding speech would never mistaken human speech however maximum naturalness always goal speech synthesis system formant synthesis systems advantages concatenative systems formant-synthesized speech reliably intelligible even high speeds avoiding acoustic glitches commonly plague concatenative systems high-speed synthesized speech used visually impaired quickly navigate computers using screen reader formant synthesizers usually smaller programs concatenative systems database speech samples therefore used embedded systems memory microprocessor power especially limited formant-based systems complete control aspects output speech wide variety prosodies intonations output conveying questions statements variety emotions tones voice examples non-real-time highly accurate intonation control formant synthesis include work done late 1970s texas instruments toy speak spell early 1980s sega arcade machines many atari inc. arcade games using tms5220 lpc chips creating proper intonation projects painstaking results yet matched real-time text-to-speech interfaces formant synthesis implemented hardware yamaha fs1r synthesizer speech aspect formants never realized synthesis capable short several-second formant sequences could speak single phrase since midi control interface restrictive live speech impossibility articulatory synthesis refers computational techniques synthesizing speech based models human vocal tract articulation processes occurring first articulatory synthesizer regularly used laboratory experiments developed haskins laboratories mid-1970s philip rubin tom baer paul mermelstein synthesizer known asy based vocal tract models developed bell laboratories 1960s 1970s paul mermelstein cecil coker colleagues recently articulatory synthesis models incorporated commercial speech synthesis systems notable exception next-based system originally developed marketed trillium sound research spin-off company university calgary much original research conducted following demise various incarnations next started steve jobs late 1980s merged apple computer 1997 trillium software published gnu general public license work continuing gnuspeech system first marketed 1994 provides full articulatory-based text-to-speech conversion using waveguide transmission-line analog human oral nasal tracts controlled carré distinctive region model recent synthesizers developed jorge c. lucero colleagues incorporate models vocal fold biomechanics glottal aerodynamics acoustic wave propagation bronqui traquea nasal oral cavities thus constitute full systems physics-based speech simulation hmm-based synthesis synthesis method based hidden markov models also called statistical parametric synthesis system frequency spectrum vocal tract fundamental frequency voice source duration prosody speech modeled simultaneously hmms speech waveforms generated hmms based maximum likelihood criterion sinewave synthesis technique synthesizing speech replacing formants main bands energy pure tone whistles deep learning-based synthesizers use deep neural networks dnn trained recorded speech data dnn-based speech synthesizers approaching quality human voice examples wavenet deepmind tacotron google deep voice uses wavenet technology baidu process normalizing text rarely straightforward texts full heteronyms numbers abbreviations require expansion phonetic representation many spellings english pronounced differently based context example latest project learn better project voice contains two pronunciations project text-to-speech tts systems generate semantic representations input texts processes unreliable poorly understood computationally ineffective result various heuristic techniques used guess proper way disambiguate homographs like examining neighboring words using statistics frequency occurrence recently tts systems begun use hmms discussed generate parts speech aid disambiguating homographs technique quite successful many cases whether read pronounced red implying past tense reed implying present tense typical error rates using hmms fashion usually five percent techniques also work well european languages although access required training corpora frequently difficult languages deciding convert numbers another problem tts systems address simple programming challenge convert number words least english like 1325 becoming one thousand three hundred twenty-five however numbers occur many different contexts 1325 may also read one three two five thirteen twenty-five thirteen hundred twenty five tts system often infer expand number based surrounding words numbers punctuation sometimes system provides way specify context ambiguous roman numerals also read differently depending context example henry viii reads henry eighth chapter viii reads chapter eight similarly abbreviations ambiguous example abbreviation inches must differentiated word address 12 st john st. uses abbreviation saint street tts systems intelligent front ends make educated guesses ambiguous abbreviations others provide result cases resulting nonsensical sometimes comical outputs ulysses s. grant rendered ulysses south grant speech synthesis systems use two basic approaches determine pronunciation word based spelling process often called text-to-phoneme grapheme-to-phoneme conversion phoneme term used linguists describe distinctive sounds language simplest approach text-to-phoneme conversion dictionary-based approach large dictionary containing words language correct pronunciations stored program determining correct pronunciation word matter looking word dictionary replacing spelling pronunciation specified dictionary approach rule-based pronunciation rules applied words determine pronunciations based spellings similar sounding synthetic phonics approach learning reading approach advantages drawbacks dictionary-based approach quick accurate completely fails given word dictionary dictionary size grows memory space requirements synthesis system hand rule-based approach works input complexity rules grows substantially system takes account irregular spellings pronunciations consider word common english yet word letter f pronounced result nearly speech synthesis systems use combination approaches languages phonemic orthography regular writing system prediction pronunciation words based spellings quite successful speech synthesis systems languages often use rule-based method extensively resorting dictionaries words like foreign names borrowings whose pronunciations obvious spellings hand speech synthesis systems languages like english extremely irregular spelling systems likely rely dictionaries use rule-based methods unusual words words n't dictionaries consistent evaluation speech synthesis systems may difficult lack universally agreed objective evaluation criteria different organizations often use different speech data quality speech synthesis systems also depends quality production technique may involve analogue digital recording facilities used replay speech evaluating speech synthesis systems therefore often compromised differences production techniques replay facilities since 2005 however researchers started evaluate speech synthesis systems using common speech dataset study journal speech communication amy drahota colleagues university portsmouth uk reported listeners voice recordings could determine better chance levels whether speaker smiling suggested identification vocal features signal emotional content may used help make synthesized speech sound natural one related issues modification pitch contour sentence depending upon whether affirmative interrogative exclamatory sentence one techniques pitch modification uses discrete cosine transform source domain linear prediction residual pitch synchronous pitch modification techniques need priori pitch marking synthesis speech database using techniques epoch extraction using dynamic plosion index applied integrated linear prediction residual voiced regions speech popular systems offering speech synthesis built-in capability mattel intellivision game console offered intellivoice voice synthesis module 1982 included sp0256 narrator speech synthesizer chip removable cartridge narrator 2kb read-only memory rom utilized store database generic words could combined make phrases intellivision games since orator chip could also accept speech data external memory additional words phrases needed could stored inside cartridge data consisted strings analog-filter coefficients modify behavior chip synthetic vocal-tract model rather simple digitized samples also released 1982 software automatic mouth first commercial all-software voice synthesis program later used basis macintalk program available non-macintosh apple computers including apple ii lisa various atari models commodore 64 apple version preferred additional hardware contained dacs although could instead use computer one-bit audio output addition much distortion card present atari made use embedded pokey audio chip speech playback atari normally disabled interrupt requests shut antic chip vocal output audible output extremely distorted speech screen commodore 64 made use 64 embedded sid audio chip arguably first speech system integrated operating system 1400xl/1450xl personal computers designed atari inc. using votrax sc01 chip 1983 1400xl/1450xl computers used finite state machine enable world english spelling text-to-speech synthesis unfortunately 1400xl/1450xl personal computers never shipped quantity atari st computers sold stspeech.tos floppy disk first speech system integrated operating system shipped quantity apple computer macintalk software licensed 3rd party developers joseph katz mark barton later softvoice inc. featured 1984 introduction macintosh computer january demo required 512 kilobytes ram memory result could run 128 kilobytes ram first mac actually shipped demo accomplished prototype 512k mac although attendance told synthesis demo created considerable excitement macintosh early 1990s apple expanded capabilities offering system wide text-to-speech support introduction faster powerpc-based computers included higher quality voice sampling apple also introduced speech recognition systems provided fluid command set recently apple added sample-based voices starting curiosity speech system apple macintosh evolved fully supported program plaintalk people vision problems voiceover first time featured 2005 mac os x tiger 10.4 10.4 tiger first releases 10.5 leopard one standard voice shipping mac os x starting 10.6 snow leopard user choose wide range list multiple voices voiceover voices feature taking realistic-sounding breaths sentences well improved clarity high read rates plaintalk mac os x also includes say command-line based application converts text audible speech applescript standard additions includes say verb allows script use installed voices control pitch speaking rate modulation spoken text apple ios operating system used iphone ipad ipod touch uses voiceover speech synthesis accessibility third party applications also provide speech synthesis facilitate navigating reading web pages translating text second operating system feature advanced speech synthesis capabilities amigaos introduced 1985 voice synthesis licensed commodore international softvoice inc. also developed original macintalk text-to-speech system featured complete system voice emulation american english male female voices stress indicator markers made possible amiga audio chipset synthesis system divided translator library converted unrestricted english text standard set phonetic codes narrator device implemented formant model speech generation.. amigaos also featured high-level speak handler allowed command-line users redirect text output speech speech synthesis occasionally used third-party programs particularly word processors educational software synthesis software remained largely unchanged first amigaos release commodore eventually removed speech synthesis support amigaos 2.1 onward despite american english phoneme limitation unofficial version multilingual speech synthesis developed made use enhanced version translator library could translate number languages given set rules language modern windows desktop systems use sapi 4 sapi 5 components support speech synthesis speech recognition sapi 4.0 available optional add-on windows 95 windows 98 windows 2000 added narrator text–to–speech utility people visual impairment third-party programs jaws windows window-eyes non-visual desktop access supernova system access perform various text-to-speech tasks reading text aloud specified website email account text document windows clipboard user keyboard typing etc programs use speech synthesis directly programs use plug-ins extensions add-ons read text aloud third-party programs available read text system clipboard microsoft speech server server-based package voice synthesis recognition designed network use web applications call centers early 1980s ti known pioneer speech synthesis highly popular plug-in speech synthesizer module available ti-99/4 4a speech synthesizers offered free purchase number cartridges used many ti-written video games notable titles offered speech promotion alpiner parsec synthesizer uses variant linear predictive coding small in-built vocabulary original intent release small cartridges plugged directly synthesizer unit would increase device built vocabulary however success software text-to-speech terminal emulator ii cartridge cancelled plan text-to-speech tts refers ability computers read text aloud tts engine converts written text phonemic representation converts phonemic representation waveforms output sound tts engines different languages dialects specialized vocabularies available third-party publishers version 1.6 android added support speech synthesis tts currently number applications plugins gadgets read messages directly e-mail client web pages web browser google toolbar specialized software narrate rss-feeds one hand online rss-narrators simplify information delivery allowing users listen favourite news sources convert podcasts hand on-line rss-readers available almost pc connected internet users download generated audio files portable devices e.g help podcast receiver listen walking jogging commuting work growing field internet based tts web-based assistive technology e.g 'browsealoud uk company readspeaker deliver tts functionality anyone reasons accessibility convenience entertainment information access web browser non-profit project created 2006 provide similar web-based tts interface wikipedia work done context w3c w3c audio incubator group involvement bbc google inc open-source software systems available 2016 introduction adobe voco audio editing generating software prototype slated part adobe creative suite similarly enabled deepmind wavenet deep neural network based audio synthesis software google speech synthesis verging completely indistinguishable real human voice adobe voco takes approximately 20 minutes desired target speech generate sound-alike voice even phonemes present training material software poses ethical concerns allows steal peoples voices manipulate say anything desired increases stress disinformation situation coupled facts number markup languages established rendition text speech xml-compliant format recent speech synthesis markup language ssml became w3c recommendation 2004 older speech synthesis markup languages include java speech markup language jsml sable although proposed standard none widely adopted speech synthesis markup languages distinguished dialogue markup languages voicexml example includes tags related speech recognition dialogue management touchtone dialing addition text-to-speech markup speech synthesis long vital assistive technology tool application area significant widespread allows environmental barriers removed people wide range disabilities longest application use screen readers people visual impairment text-to-speech systems commonly used people dyslexia reading difficulties well pre-literate children also frequently employed aid severe speech impairment usually dedicated voice output communication aid speech synthesis techniques also used entertainment productions games animations 2007 animo limited announced development software application package based speech synthesis software finespeech explicitly geared towards customers entertainment industries able generate narration lines dialogue according user specifications application reached maturity 2008 nec biglobe announced web service allows users create phrases voices characters recent years text speech disability handicapped communication aids become widely deployed mass transit text speech also finding new applications outside disability market example speech synthesis combined speech recognition allows interaction mobile devices via natural language processing interfaces text-to speech also used second language acquisition voki instance educational tool created oddcast allows users create talking avatar using different accents emailed embedded websites shared social media addition speech synthesis valuable computational aid analysis assessment speech disorders voice quality synthesizer developed jorge c. lucero et al university brasilia simulates physics phonation includes models vocal frequency jitter tremor airflow noise laryngeal asymmetries synthesizer used mimic timbre dysphonic speakers controlled levels roughness breathiness strain
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Computational linguistics
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dopipe dopipe parallelism method perform loop-level parallelism pipelining statements loop pipelined parallelism may exist different levels abstraction like loops functions algorithmic stages extent parallelism depends upon programmers ability make best use concept also depends upon factors like identifying separating independent tasks executing parallelly main purpose employing loop-level parallelism search split sequential tasks program convert parallel tasks without prior information algorithm parts data recurring consume significant amount execution time good candidates loop-level parallelism common applications loop-level parallelism found mathematical analysis uses multiple-dimension matrices iterated nested loops different kind parallelization techniques used basis data storage overhead degree parallelization data dependencies known techniques doall doacross dopipe doall technique used parallelize iteration loop without interaction iterations hence overall run-time gets reduced n serial processor execution time iteration since n iterations executed parallel doacross technique used wherever possibility data dependencies hence parallelize tasks manner data independent tasks executed parallel dependent ones executed sequentially degree synchronization used sync dependent tasks across parallel processors dopipe pipelined parallelization technique used programs element produced iteration consumed later iteration following example shows implement dopipe technique reduce total execution time breaking tasks inside loop executing pipelined manner breaking tasks takes place way dependencies within loop unidirectional i.e following iteration depend previous iteration program shows pseudocode dopipe parallelization code see three tasks f0 f1 f2 inside loop iterating codice_1 1 codice_2 following list dependencies code f1 j → f1 j+1 implies statement f1 iteration codice_3 must executed statement f1 iteration codice_1 also known true dependency f1 j → f2 j implies statement f2 iteration codice_1 must executed statement f1 iteration codice_1.if code would executed sequentially total time consumed would equal n denote execution time functions f0 f1 f2 respectively per iteration parallelize loop pipelining statements inside loop following manner since f0 independent function i.e loop-carried dependency dependence codice_3 codice_8 iterations neither dependency across statements loop hence completely separate function run parallelly using doall parallelism hand statements f1 f2 dependent explained therefore split two different loops execute pipelined fashion use codice_9 codice_10 synchronize f1 f2 loops starting first iteration codice_1 statement f1 gets executed time meanwhile f2 getting executed since waiting value codice_12 produced f1 f1 completes execution iteration codice_1 posts value using codice_9 waiting f1 execution using codice_10 f2 starts execution since value codice_12 available use also since f1 execution restricted f2 hence f1 executes codice_3 simultaneously figure shows execution timeline statements figure see total time execute f0 since iterations f0 executed parallel f1 f2 total execution time equal n considering negligible synchronization time considerably less time obtained sequential execution doall parallelism mainly works principle divide conquer tasks run different iterations use unique set data problem implementation large amount data works computed together large cache space needed work different threads since dependencies threads overhead inter thread communication dopipe synchronization overhead threads due pipelined structure requires less cache space data produced immediately consumed consumer
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Computer architecture
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snipping tool snipping tool microsoft windows screenshot utility included windows vista later take still screenshots open window rectangular areas free-form area entire screen snips annotated using mouse tablet stored image file png gif jpeg file mhtml file e-mailed snipping tool allows basic image editing snapshot different colored pens eraser highlighter windows vista snipping tool included experience pack windows xp tablet pc edition 2005 originally released powertoy microsoft tablet pc launch november 7 2002 windows 10 adds new delay function allows timed capture screenshots replaced snip sketch windows 10 october 2018 update still available october 2018 update microsoft says removed future update delay function valuable taking screenshot showing context menus handles appear around graphic object object selected without delay feature would possible take screenshot showing context menus object handles disappear item snipping tool clicked use delay feature one opens snipping tool sets delay seconds delay one opens context menu selects object handles appear waits delay lapse end delay snipping tool automatically becomes active without user click therefore context menu object handles disappear screenshot taken
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Operating systems
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burgertime united states data east usa licensed burgertime distribution bally midway standard dedicated arcade game data east also released version burgertime united states deco cassette system data east midway versions distinguished manufacturer name title screen marquee cabinet artworks game identical game original japanese title changed outside japan burgertime reportedly avoid potential trademark issues addition releases western world burgertime also name used japanese ports sequels data east went bankrupt 2003 g-mode bought data east intellectual properties including burgertime burgertime deluxe super burgertime peter pepper ice cream factory object game complete number hamburgers avoiding enemy foods player controls protagonist chef peter pepper four-position joystick button board consists maze planks ladders giant burger ingredients buns patties lettuce/tomato etc laid peter walks full length ingredient falls level knocking ingredient happens burger completed vertically aligned ingredients dropped maze onto waiting plate player must complete burgers finish board three types enemy food items wander maze mr hot dog mr. pickle mr egg player score extra points either crushing falling ingredient dropping ingredient standing latter case ingredient falls two extra levels every enemy caught crushed dropped enemies return maze short time start game player given limited number pepper shots use enemies pressing button causes peter shake cloud pepper direction facing enemy touching cloud stunned seconds peter safely move bonus food items coffee ice cream appear occasion awarding bonus points one extra pepper shot collected six boards increasing difficulty burgers/ingredients enemies and/or layouts make easier peter become cornered enemies player completes sixth board cycle repeats player loses one life whenever peter touches non-stunned enemy lives lost game mattel electronics obtained rights burgertime data east released intellivision version 1983 year also released versions atari 2600 ibm pc apple ii aquarius 1984 mattel produced colecovision version distributed coleco data east produced version ti-99/4a 1983 famicom 1985 msx 1986 nes 1987 burgertime received certificate merit category 1984 videogame year less 16k rom 5th annual arkie awards deseret news called burgertime one real surprises 1983 intellivision gave colecovision version three one half stars arcade spin-off peter pepper ice cream factory 1984 arcade sequel 1990 widely released super burgertime stars peter pepper jr. allows two players play fairly true original many added features greatly improved graphics console-only sequel diner created 1984 purchase intellivision mattel intv corp programmed ray kaestner programmer intellivision version burgertime diner peter pepper must kick balls food roll platforms ramps land large plate bottom screen avoiding crushing enemy food items trying stop burgertime deluxe released game boy 1991 namco released burgertime delight mobile devices 2007 includes new graphics characters power-ups six arcade levels eight enhanced mode levels perils falling ice rising fire grill besides pepper classic game salt shaker collected stuns enemies screen 3d update burgertime world tour released 2011 xbox live arcade playstation network 2012 wiiware delisted xbox live arcade april 30 2014 arcade version burgertime included various collections including arcade greatest hits midway collection 2 playstation data east arcade classics wii nes version available wii virtual console burgertime deluxe released 3ds virtual console 2011 nes version also included 2017 compilation data east all-star collection nintendo entertainment system clones home systems include mr. wimpy burger chase burger time interceptor micros burgerspace chip factory burger boy basic burger barmy burgers burger builder lunchtime peter pepper appeared movies wreck-it ralph pixels elements burgertime episode gameboy 1984 billy mitchell achieved record score 7,881,050 beaten september 5 2005 bryan l. wagner turbotville pennsylvania score 8,601,300 improved exactly 9,000,000 june 2 2006 according twin galaxies improved 11,512,500 points september 19 2008 challenge arcade wyomissing pennsylvania mame world record verified twin galaxies december 2 2016 7,837,750 roger edwin blair iii mountain city tennessee
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Computer architecture
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mobile internet device mobile internet device mid multimedia-capable mobile device providing wireless internet access designed provide entertainment information location-based services personal business use allow 2-way communication real-time sharing described filling niche smartphones tablet computers features mid started becoming available smartphones tablets term mostly used refer low-end well high-end tablets form factor mobile internet tablets archos similar lenovo image right class included multiple operating systems windows ce windows 7 android android tablet uses arm cortex cpu touchscreen intel announced prototype mid intel developer forum spring 2007 beijing mid development kit sophia systems using intel centrino atom announced april 2008 intel mid platforms based intel processor chipset consume less power x86 derivatives platforms announced listed intel first generation mid platform codenamed mccaslin contains 90 nm intel a100/a110 processor codenamed stealey runs 600–800 mhz 2 march 2008 intel introduced intel atom processor brand new family low-power processor platforms components thin small designs work together enable best mobile computing internet experience mobile low-power devices intel second generation mid platform codenamed menlow contains 45 nm intel atom processor codenamed silverthorne run 2.0 ghz system controller hub codenamed poulsbo includes intel hd audio codenamed azalia platform initially branded centrino atom practice discontinued q3 2008 intel third generation mid/smartphone platform codenamed moorestown contains 45 nm intel atom processor codenamed lincroft 65 nm platform controller hub codenamed langwell since memory controller graphics controller integrated processor northbridge removed processor communicates directly southbridge via dmi bus interface intel fourth generation mid/smartphone platform codenamed medfield contains 32 nm intel atom soc codenamed penwell intel mid/smartphone platform codenamed clover trail+ based clover trail tablet platform contains 32 nm intel atom soc codenamed cloverview intel fifth generation mid/smartphone platform codenamed merrifield contains 22 nm intel atom soc codenamed tangier intel sixth generation mid/smartphone platform codenamed moorefield contains 22 nm intel atom soc codenamed anniedale intel seventh generation mid/smartphone platform codenamed morganfield contains 14 nm intel atom soc codenamed broxton intel announced collaboration ubuntu create ubuntu mobile internet devices distribution known ubuntu mobile ubuntu website said new distribution provide rich internet experience users intel ’ 2008 mobile internet device mid platform
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Operating systems
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microsoft jhenghei microsoft jhenghei 微軟正黑體 sans-serif typeface included windows vista later microsoft office 2007 follows standard form national characters prescribed ministry education republic china taiwan intended used traditional chinese language environments using cleartype version microsoft jhenghei alternate character design versions microsoft jhenghei microsoft jhenghei ui respectively sold monotype family includes light version font microsoft jhenghei tc light microsoft jhenghei ui tc light downloading installing traditional chinese cleartype fonts windows xp microsoft also makes microsoft jhenghei available windows xp microsoft jhenghei ui included windows 8 later
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Operating systems
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banner grabbing banner grabbing technique used gain information computer system network services running open ports administrators use take inventory systems services network however intruder use banner grabbing order find network hosts running versions applications operating systems known exploits examples service ports used banner grabbing used hyper text transfer protocol http file transfer protocol ftp simple mail transfer protocol smtp ports 80 21 25 respectively tools commonly used perform banner grabbing telnet nmap zmap netcat example one could establish connection target web server using netcat send http request response typically contain information service running host information may used administrator catalog system intruder narrow list applicable exploits prevent network administrators restrict access services networks shut unused unnecessary services running network hosts shodan search engine banners grabbed portscanning internet
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Computer security
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powerpc e600 powerpc e600 family 32-bit powerpc microprocessor cores developed freescale primary use high performance system-on-a-chip soc designs speed ranging 2 ghz thus making ideal high performance routing telecommunications applications e600 continuation powerpc 74xx design e600 superscalar out-of-order risc core 32/32 kb l1 data/instruction caches seven-stage three-issue pipeline load/store system register powerful branch prediction integer unit double precision fpu enhanced 128-bit altivec unit limited out-of-order execution core designed work multiprocessing multi core designs take large amounts l2 caches die e600 core completely backwards compatible powerpc 74xx cores derives 2004 freescale renamed powerpc 74xx core e600 changed focus general cpus high end embedded soc devices introduced new naming scheme mpc86xx 7448 last pure 74xx formed base new e600 core 7448 evolution powerpc 7447 essentially faster 2 ghz power-efficient version 7447a manufactured 90 nm 1 mb l2 cache 200 mhz front side bus features freescale new standard core e600 problems associated bandwidth-constrained external mpx bus interface found 74xx series relieved single mpc8641 dual mpc8641d e600 cores faster system interface via rapidio dual x8 pci express on-die 667 mhz mpx interconnect i/o cores dual 64-bit ddr2-memory controllers ecc product also features four on-chip gigabit ethernet controllers tcp/udp offloading features dual core mpc8641d support asymmetric multiprocessing enables two operating systems run device simultaneously sharing resources largely unaware mpc8641 single core mpc8641d dual core manufactured 90 nm soi based process 8641 draws less 16w 1.33 ghz 8641d less 25w 1.5 ghz introduced summer 2008 mpc8640 mpc8640d low power low cost versions mpc8641 parts clocked 1-1.25 ghz draw 14-21w power identical older brethren respects introduced 2007 mpc8610 host processor integrated graphics processor supporting 24-bit screens sizes 1280x1024 pixels single core cpu 256 kb die l2 cache manufactured 90 nm process reaches speeds 667 1333 mhz list complete list known core e600 based designs excluding older 74xx designs pictures illustrations scale
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Computer architecture
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tora tora toolkit oracle free software database development administration gui available gnu general public license features pl/sql debugger sql worksheet syntax highlighting database browser comprehensive set database administration tools addition oracle database support support mysql postgresql teradata databases added since initial launch uses qt use qscintilla2 library oracle connector uses oracle template library tora originally written henrik johnson copyright globecom ab acquired quest software start conversion maintained open source project made 2005-02-17 version 1.3.15 qt4 conversion took place 2009 version 1.4
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Databases
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b2g os b2g os community-developed successor firefox os developed mozilla foundation follows firefox os vision providing complete community-based alternative operating system runs software web applications software 'applications therefore use open web standards programming languages javascript html5 robust privilege model open web apis communicate directly device hardware basis kaios jan 2019 17 percent indian mobile phone market third popular phone os kaios closed-source b2g os forked firefox os following mozilla decision discontinue support mobile operating system decision made according ari jaaksi david bryant order evolve quickly enable substantial new architectural changes gecko mozilla ’ platform engineering organization needs remove b2g-related code mozilla-central 2017 b2g os longer maintained
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Operating systems
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bounder video game courses composed numerous tiles suspended high ground ball must bounced past walls enemies coming contact either plummeting edge course results loss one player seven lives courses feature power squares push tennis ball forward allow longer jumps must utilized complete course power squares also used enable tennis ball reach mystery spaces tiles question marks contain extra lives bonus jumps used bonus screens mystery spaces also destroy tennis ball resulting loss life instant destruction freezing ball place missile flies across play area explodes bonus screen accessed every time course completed consists mystery spaces increase player score bounced player receive 40 bounces allowed bonus screen though figure increased player uncovering mystery squares preceding course bounces used mystery spaces bounced play moves next course bouncing mystery spaces awards player 10,000 points well extra life bounder received gold medal award commodore 64 magazine zzap 64 well sinclair mega game award remake bounder released mobile game swivel creations may 2019
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Computer architecture
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national cyber investigative joint task force national cyber investigative joint task force ncijtf officially established 2008 ncijtf comprises 20 partnering agencies across law enforcement intelligence community department defense representatives co-located work jointly accomplish organization ’ mission since 2008 ncijtf primary american agency responsible coordinating cyber threats investigations liaisons central intelligence agency cia department defense dod department homeland security dhs national security agency nsa multi-agency cyber center ncijtf coordinates integrates shares information support cyber threat investigations supply support intelligence analysis community decision-makers support efforts fight cyber threats task force uses collective resources members collaborates international private sector partners bring available resources bear domestic cyber threats perpetrators
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Computer security
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jetty web server eclipse jetty java http web server java servlet container web servers usually associated serving documents people jetty often used machine machine communications usually within larger software frameworks jetty developed free open source project part eclipse foundation web server used products apache activemq alfresco scalatra apache geronimo apache maven apache spark google app engine eclipse fuse idempiere twitter streaming api zimbra jetty also server open source projects lift eucalyptus opennms red5 hadoop i2p jetty supports latest java servlet api jsp support well protocols http/2 websocket jetty started independent open source project 1995 2009 jetty moved eclipse jetty provides web services embedded java application already component eclipse ide supports ajp jaspi jmx jndi osgi websocket java technologies originally developed software engineer greg wilkins jetty originally http server component mort bay server originally called issuetracker original application mbservler mort bay servlet server neither much liked jetty finally picked jetty started 1995 hosted mortbay creating version 1.x 2.x 2000 2000 2005 jetty hosted sourceforge.net version 3.x 4.x 5.x produced 2005 entire jetty project moved codehaus.org 2009 core components jetty moved eclipse.org codehaus.org continued provide integrations extensions packaging jetty versions 7.x 8.x 9.x 2016 main repository jetty moved github still developed eclipse ip process documentation
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Web technology
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telesign telesign corporation communications platform service company founded security based los angeles california founded 2005 darren berkovitz ryan disraeliand stacy stubblefield company mainly provides two-factor authentication services secure supplementary method preventing illicit access online accounts used many companies like itunes yahoo gmail outlook twitter facebook bank america chase discover paypal etsy salesforce company also offers variety cloud communications apis via self-service portal ryan disraeli current ceo company along co-founders disraeli stubblefield berkowitz named usc alumni entrepreneurs year telesign early project technology incubator curious minds company raised 49 million funds april 2017 telesign announced acquired bics belgium-based company 230 million
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Computer security
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hardware performance counter computers hardware performance counters hardware counters set special-purpose registers built modern microprocessors store counts hardware-related activities within computer systems advanced users often rely counters conduct low-level performance analysis tuning number available hardware counters processor limited cpu model might lot different events developer might like measure counter programmed index event type monitored like l1 cache miss branch misprediction one first processors implement counter associated instruction codice_1 access intel pentium documented terje mathisen wrote article reverse engineering byte july 1994 following table shows examples cpus number available hardware counters compared software profilers hardware counters provide low-overhead access wealth detailed performance information related cpu functional units caches main memory etc another benefit using source code modifications needed general however types meanings hardware counters vary one kind architecture another due variation hardware organizations difficulties correlating low level performance metrics back source code limited number registers store counters often force users conduct multiple measurements collect desired performance metrics modern superscalar processors schedule execute multiple instructions out-of-order one time in-flight instructions retire time depending memory access hits cache stalls pipeline many factors cause performance counter events attributed wrong instructions making precise performance analysis difficult impossible amd introduced methods mitigate drawbacks example opteron processors implemented 2007 technique known instruction based sampling ibs amd implementation ibs provides hardware counters fetch sampling front superscalar pipeline op sampling back pipeline results discrete performance data associating retired instructions parent amd64 instruction
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Computer architecture
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extended display identification data extended display identification data edid metadata format display devices describe capabilities video source e.g graphics card set-top box data format defined standard published video electronics standards association vesa edid data structure includes manufacturer name serial number product type phosphor filter type timings supported display display size luminance data digital displays pixel mapping data displayid vesa standard targeted replace edid e-edid extensions uniform format suited pc monitor consumer electronics devices edid structure versions range v1.0 v1.4 define upwards-compatible 128-byte structures version 2.0 defined new 256-byte structure deprecated replaced v1.3 supports multiple extension blocks hdmi versions 1.0–1.3c use edid structure v1.3 display data channel ddc edid defined standard way graphics card know kind display device connected vga connectors personal computers provided basic form identification connecting one two three pins ground coding standardized channel transmitting edid display graphics card usually i²c-bus defined ddc2b ddc1 used different serial format never gained popularity edid often stored monitor memory device called serial prom programmable read-only memory eeprom electrically erasable prom accessible via i²c-bus address edid prom often read host pc even display turned many software packages read display edid information read-edid linux dos powerstrip microsoft windows xfree86 linux bsd unix mac os x natively reads edid information programs switchresx displayconfigx display information well use define custom resolutions enhanced edid introduced time e-ddc introduced edid structure version 1.3 supports multiple extensions blocks deprecated edid version 2.0 structure although supported extension data fields preferred timing range limits monitor name required e-edid e-edid also supports dual gtf timings aspect ratio change use extensions e-edid string lengthened 32 kbytes graphics card drivers historically coped poorly edid using standard timing descriptors rather detailed timing descriptors dtds even cases dtds read drivers are/were still often limited standard timing descriptor limitation horizontal/vertical resolutions must evenly divisible 8 means many graphics cards express native resolutions common wide screen flat panel displays liquid crystal display televisions number vertical pixels calculated horizontal resolution selected aspect ratio fully expressible size wide screen display must thus multiple 16×9 pixels 1366×768 pixel wide xga panels nearest resolution expressible edid standard timing descriptor syntax 1360×765 pixels typically leading 3 pixel thin black bars specifying 1368 pixels screen width would yield unnatural screen height 769.5 pixels many wide xga panels advertise native resolution standard timing descriptors instead offering resolution 1280×768 panels advertise resolution slightly smaller native 1360×765 panels able show pixel perfect image edid data must ignored display driver driver must correctly interpret dtd able resolve resolutions whose size divisible 8 special programs available override standard timing descriptors edid data even always possible vendors graphics drivers notably intel require specific registry hacks implement custom resolutions make difficult use screen native resolution used another descriptor pixel clock bytes set 0 currently defined descriptor types cea edid timing extension first introduced eia/cea-861 since updated several times notably −861b revision version 3 extension adding short video descriptors advanced audio capability/configuration information −861d published july 2006 containing updates audio segments −861e −861f published june 4 2013 according brian markwalter senior vice president research standards cea −861f includes number noteworthy enhancements including support several new ultra hd widescreen video formats additional colorimetry schemes. ” recent version cta-861-g originally published november 2016 made available free november 2017 necessary changes due trademark complaint version 1 defined −861 allowed specification video timings use 18-byte detailed timing descriptors dtd detailed edid 1.3 data format cases preferred timing first dtd listed cea edid timing extension version 2 defined −861a added capability designate number dtds native also included basic discovery functionality whether display device contains support basic audio ycbcr pixel formats underscan version 3 −861b spec allows two different ways specify timings available digital tv formats version 1 2 use 18-byte dtds use short video descriptor svd see hdmi 1.0–1.3c uses version version 3 also includes four new optional types data blocks video data blocks containing aforementioned short video descriptor svd audio data blocks containing short audio descriptors sad speaker allocation data blocks containing information speaker configuration display device vendor specific data blocks contain information specific given vendor use data block collection contains one data blocks detailing video audio speaker placement information display blocks placed order initial byte block defines type length one data block ended next byte assumed beginning next data block case byte designated byte 2 dtds known begin audio data blocks contain one 3-byte short audio descriptors sads sad details audio format channel number bitrate/resolution capabilities display follows video data blocks contain one 1-byte short video descriptors svds notes parentheses indicate instances pixels repeated meet minimum speed requirements interface example 720x240p case pixels line double-clocked 2880 x480i case number pixels line thus number times repeated variable sent dtv monitor source device increased hactive expressions include “ 2x ” “ 4x ” indicate two four times reference resolution respectively video modes vertical refresh frequency multiple 6hz i.e 24 30 60 120 240hz considered timing equivalent ntsc modes vertical refresh adjusted factor 1000/1001 vesa dmt specifies 0.5 pixel clock tolerance 5 times required change pixel clocks adjusted maintain ntsc compatibility typically 240p 480p 480i modes adjusted 576p 576i hdtv formats vendor specific data block contains first three bytes vendor ieee 24-bit registration number lsb first hdmi always hdmi licensing llc followed two byte source physical address lsb first source physical address provides cec physical address upstream cec devices remainder vendor specific data block data payload anything vendor considers worthy inclusion edid extension block hdmi 1.3a specifies requirements data payload see spec detailed info bytes speaker allocation data block present consist three bytes second third reserved first contains information speakers present display device
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Computer architecture
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bounce address tag validation computing bounce address tag validation batv method defined internet draft determining whether bounce address specified e-mail message valid designed reject backscatter bounce messages forged return addresses basic idea send e-mail return address includes timestamp cryptographic token forged e-mail returned bounce without valid signature rejected e-mail bounced back empty null return address bounces never created bounce therefore ca n't get messages bouncing back forth forever batv replaces envelope sender like codice_1 codice_2 codice_3 called simple private signature one possible tagging schemes actually one fully specified draft batv draft gives framework possible techniques fit types implementations using public key signatures verified third parties mentioned left undefined overall framework vague/flexible enough similar systems sender rewriting scheme fit framework sami farin proposed anti-bogus bounce system 2003 news.admin.net-abuse.email used basic idea putting hard forge hash message bounce address late 2004 goodman et al proposed much complex signed envelope sender included hash message body intended address wide variety forgery threats including bounces forged mail several months later levine crocker proposed batv current name close current form draft anticipates problems running batv also problems prevent batv systems eliminating backscatter
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Computer security
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xsplash xsplash software project ubuntu community uses x window system replace scrolling-text screens appear booting linux-based computer graphical splash screen xsplash replaced usplash uses linux framebuffer ubuntu 9.10 karmic koala bringing ubuntu closer goal 10-second boot time ubuntu 10.04 lts lucid lynx improved boot performance usplash boot systems achieved prioritizing startup processes related x server using single x server throughout boot process
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Operating systems
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michael j. karels michael j mike karels american software engineer one key people history bsd unix graduate university notre dame bachelor science microbiology mike went university california berkeley advanced degree microbiology mike access department computer since administrator pdp-11 enough time mike started helping making changes system mike started contribution unix 2.9bsd release distributed pdp-11 mike saw job posting computer systems research group bsd project decided jump 1982 mike took bill joy responsibilities mr. joy left csrg system architect 4.3bsd important bsd release base development number commercial unix flavors available today including solaris release introduced world deep detail all-time famous book design implementation 4.3bsd unix operating system black cover smiling beastie mike csrg principal programmer 8 years mike worked closely van jacobson number widely accepted algorithms tcp implementation including jacobson/karels algorithm tcp slow start routing radix tree probably famous ones mike spends little time taking credit work hand uses every opportunity mention names people one way role contribution tcp/ip implementation unix 1993 usenix association gave lifetime achievement award flame computer systems research group university california berkeley honoring 180 individuals including karels contributed csrg 4.4bsd-lite release later mike moved bsdi berkeley software design designed bsd/os years commercially available bsd style unix intel platform bsd/os reliable os platform designed internet services bsdi software asset bought wind river april 2001 mike joined wind river principal technologist bsd/os platform 2009 mike sr principal engineer mcafee 2015 worked intel later forcepoint llc
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Operating systems
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risk information technology risk risk it-related risk cyber risk risk related information technology information long appreciated valuable important asset rise knowledge economy digital revolution led organizations becoming increasingly dependent information information processing especially various events incidents compromise way therefore cause adverse impacts organization business processes mission ranging inconsequential catastrophic scale assessing probability likelihood various types event/incident predicted impacts consequences occur common way assess measure risks alternative methods measuring risk typically involve assessing contributory factors threats vulnerabilities exposures asset values risk potential given threat exploit vulnerabilities asset group assets thereby cause harm organization measured terms combination probability occurrence event consequence committee national security systems united states america defined risk different documents national information assurance training education center defines risk field many nist publications define risk context different publications fismapedia term provide list nist sp 800-30 defines risk probable frequency probable magnitude future loss isaca published risk framework order provide end-to-end comprehensive view risks related use risk defined according risk risk broader meaning encompasses negative impact operations service delivery bring destruction reduction value organization also benefit\value enabling risk associated missing opportunities use technology enable enhance business project management aspects like overspending late delivery adverse business impact measuring risk cyber risk occur many levels business level risks managed categorically front line departments noc tend measure discreet individual risks managing nexus key role modern ciso measuring risk kind selecting correct equation given threat asset available data important step subject unto common components risk equations helpful understand four fundamental forces involved risk management also apply cybersecurity assets impact threats likelihood internal knowledge fair amount control assets tangible intangible things value also control impact refers loss damage asset however threats represent adversaries methods attack external control likelihood wild card bunch likelihoods determine threat materialize succeed damage never fully control likelihoods shaped influenced manage risk mathematically forces represented formula formula_1 p likelihood threat materialize/succeed asset likelihood various levels damage may occur field risk management spawned number terms techniques unique industry industry terms yet reconciled example term vulnerability often used interchangeably likelihood occurrence problematic often encountered risk management terms techniques include risk r product likelihood l security incident occurring times impact incurred organization due incident likelihood security incident occurrence function likelihood threat appears likelihood threat successfully exploit relevant system vulnerabilities consequence occurrence security incident function likely impact incident organization result harm organization assets sustain harm related value assets organization asset different values different organizations r function four factors numerical values money impact probabilities factors risk expressed monetary terms compared cost countermeasures residual risk applying security control always practical express values first step risk evaluation risk graded dimensionless three five steps scales owasp proposes practical risk measurement guideline based nist cybersecurity framework encourages organizations manage risk part identify id function risk assessment id.ra organization understands cybersecurity risk organizational operations including mission functions image reputation organizational assets individuals risk management strategy id.rm organization ’ priorities constraints risk tolerances assumptions established used support operational risk decisions following brief description applicable rules organized source oecd issued following european union issued following divided topic united states issued following divided topic list chiefly based
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Computer security
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