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trap computing computing operating systems trap also known exception fault typically type synchronous interrupt caused exceptional condition e.g. breakpoint division zero invalid memory access trap usually results switch kernel mode wherein operating system performs action returning control originating process trap system process serious trap user process systems fatal usages term trap refers specifically interrupt intended initiate context switch monitor program debugger deriving original usage trap sometimes used mechanism intercepting normal control flow domains snmp trap type pdu used report alert asynchronous event managed subsystem
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Operating systems
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360 safeguard 360 safeguard 360 total security program developed qihoo 360 internet security company based china 360 safeguard focus stopping malware computer viruses trojan horses providing security patches microsoft windows 360 safeguard trojan horse scanner cloud-based heuristics engine built scanner 2010 360 safeguard analyzed qq protocol accused qq automatically scanning users computers uploading personal information qq servers without users consent response tencent called 360 malware denied users 360 installed access qq services chinese ministry industry information reprimanded companies improper competition ordered come accord 30 april 2015 three independent security testing bodies av-comparatives av-test virus bulletin published joint press release criticizing qihoo 360 found qihoo 360 submitted products comparative behaved significantly different end user products products comparative used engine bitdefender end user products use qihoo 360 qvm engine instead testing bodies claimed end user products would provide considerably lower level protection higher likelihood false positives consequence three testing bodies revoked certifications rankings earlier year qihoo 360 denied cheating allegations claiming qvm engine developed qihoo 360 would effective china
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Computer security
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sse5 sse5 short streaming simd extensions version 5 simd instruction set extension proposed amd august 30 2007 supplement 128-bit sse core instructions amd64 architecture amd chose implement sse5 originally proposed may 2009 amd replaced sse5 three smaller instruction set extensions named xop fma4 f16c retain proposed functionality sse5 encode instructions differently better compatibility intel proposed avx instruction set three sse5-derived instruction sets introduced bulldozer processor core released october 2011 32 nm process amd sse5 extension bundle include full set intel sse4 instructions making competitor sse4 rather successor complicates software development recommended practice program test presence instruction set extensions means cpuid instruction entering code path depends upon instructions function correctly maximum portability optimized application require three code paths base code path compatibility older processors either vendor separately optimized intel code path exploiting sse4 avx separately optimized amd code path exploiting sse5 due proliferation benchmarks intel amd processors increasingly reflect cleverness implementation quality divergent code paths rather strength underlying platform proposed sse5 instruction set consisted 170 instructions including 46 base instructions many designed improve single-threaded performance sse5 instructions 3-operand instructions use increase average number instructions per cycle achievable x86 code selected new instructions include amd claims sse5 provide dramatic performance improvements particularly high-performance computing hpc multimedia computer security applications including 5x performance gain advanced encryption standard aes encryption 30 performance gain discrete cosine transform dct used process video streams detailed information consult instruction sets subsequently divided sse5 specification included proposed extension general coding scheme x86 instructions order allow instructions two operands 2008 intel announced planned avx instruction set proposed different way coding instructions two operands two proposed coding schemes sse5 avx mutually incompatible although avx scheme certain advantages sse5 scheme importantly avx plenty space future extensions including larger vector sizes may 2009 amd published revised specification planned future instructions revision changes coding scheme make compatible avx scheme differing prefix byte order avoid overlap instructions introduced amd instructions introduced intel revised instruction set longer carries name sse5 criticized misleading instructions new revision functionally identical original sse5 specification—only way instructions coded differs planned additions amd instruction set consists three subsets new instruction sets include support future extensions vector size 128 bits 256 bits unclear preliminary specifications whether bulldozer processor support 256-bit vector registers ymm registers
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Computer architecture
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cimtrak cimtrak computer software file integrity monitoring regulatory compliance auditing assists ensuring availability integrity critical assets detecting root-cause responding immediately unexpected changes host operating system applications network devices located infrastructure cimtrak works cross-platform supported multiple windows linux unix macintosh operating systems licensed commercial software cimtrak multiple core components cimtrak many functions detect additions deletions modifications files configurations computer operating systems components installed operating system initial configuration takes snapshot files configurations operating system uses data create cryptographic hash files configurations stores securely cimtrak master repository known good baseline cimtrak agents installed operating systems containing data configured monitoring case network device agent installed systems tcp/ip network connection supported network devices agent detects changes made monitored files configurations communicating kernel comparing changes known cryptographic hash associated affected files configurations calculated cryptographic hash different known baseline cimtrak initiate user-configured corrective action defined cimtrak object group policy send internal external event notifications using one many following methods cimtrak provides insight infrastructure detecting changes could compromise servers networks sensitive customer data payment card information payment card industry data security standard pci provide instant change remediation options without requiring integration external applications change detected cimtrak captures change exact moment occurs provides detailed audit trail incident including cimtrak report automated response taken configured initiate remediation automated responses termed corrective actions include corrective actions defined based type change action file/configuration addition file/configuration change file/configuration deletion addition automated remediation functionality cimtrak automatically launch different custom scripts based detected change type cimtrak file system agents network device agents perform change management functions monitoring file configurations based configured object group watch policies abilities vary operating system cimtrak plug-ins enhance abilities cimtrak adding additional monitoring functions attach tofile system agents network device agents plug-ins include cimtrak constructed follow software communication security standards government security product certifications information stored within cimtrak secure external modification access data rest data transit encrypted using cimcor cryptographic module several certifications including federal information processing standard fips publication 140-2 fips pub 140-2 u.s. government computer security standard used accredit cryptographic modules level 1 indicates cryptographic module supports lowest level acceptable security security level 1 allows cryptographic module executed using unevaluated operating system security level 2 enhances physical security mechanisms security level 1 adding requirement tamper-evidence protection common criteria information technology security evaluation common criteria cc international standard international organization standardization iso international electrotechnical commission iec 15408 computer security certification common criteria allows specifying verifying vendor claims relating security functionality assurance requirements verification claims performed using approved testing laboratories evaluation assurance level eal4 permits developer gain maximum assurance positive security engineering based good commercial development practices though rigorous require substantial specialist knowledge skills resources eal4 highest level likely economically feasible retrofit existing product line eal4 therefore applicable circumstances developers users require moderate high level independently assured security conventional commodity toes prepared incur additional security-specific engineering costs augmented alc_flr.2 establishes verifies claim developer established flaw remediation procedures describe tracking security flaws identification corrective actions distribution corrective action information toe users cimcor flagship software cimtrak file integrity monitoring tool department defense unified capabilities approved products list unique factor allows cimtrak file integrity monitoring product available use within department defense boundaries products contained united states army approved products list deemed acceptable use within boundaries united states army cimtrak application used facilitate following compliance security objectives microsoft windows versions linux versions microsoft windows versions microsoft windows versions unix linux versions
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Computer security
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gtri cyber technology information security laboratory cyber technology information security laboratory ctisl one eight labs georgia tech research institute created october 1 2010 focuses cyber security along gtri information communications laboratory part information cyber sciences directorate gtri ctisl known commitment open source software feature existing business areas secure information systems resilient command control emerging areas cyberwarfare laboratory additionally part georgia tech information security center
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Computer security
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android software development android software development process new applications created devices running android operating system google states android apps written using kotlin java c++ languages using android software development kit sdk using languages also possible non-jvm languages go javascript c c++ assembly need help jvm language code may supplied tools likely restricted api support programming languages tools allow cross-platform app support i.e android ios third party tools development environments language support also continued evolve expand since initial sdk released 2008 addition major business entities like walmart amazon bank america eyeing engage sell mobiles mobile application development witnessing transformation android software development kit sdk includes comprehensive set development tools include debugger libraries handset emulator based qemu documentation sample code tutorials currently supported development platforms include computers running linux modern desktop linux distribution mac os x 10.5.8 later windows 7 later sdk available android software development possible using specialized android applications around end 2014 officially-supported integrated development environment ide eclipse using android development tools adt plugin though intellij idea ide editions fully supports android development box netbeans ide also supports android development via plugin 2015 android studio made google powered intellij official ide however developers free use others google made clear adt officially deprecated since end 2015 focus android studio official android ide additionally developers may use text editor edit java xml files use command line tools java development kit apache ant required create build debug android applications well control attached android devices e.g. triggering reboot installing software package remotely enhancements android sdk go hand-in-hand overall android platform development sdk also supports older versions android platform case developers wish target applications older devices development tools downloadable components one downloaded latest version platform older platforms tools also downloaded compatibility testing android applications packaged .apk format stored codice_1 folder android os folder accessible root user security reasons apk package contains .dex files compiled byte code files called dalvik executables resource files etc android sdk platform tools separately downloadable subset full sdk consisting command-line tools codice_2 codice_3 android debug bridge adb tool run commands connected android device codice_4 daemon runs device codice_2 client starts background server multiplex commands sent devices addition command-line interface numerous graphical user interfaces exist control adb format issuing commands typically example android applications saved command codice_6 file whose name codice_7 default security issue reported march 2011 adb targeted vector attempt install rootkit connected phones using resource exhaustion attack fastboot protocol tool name included android sdk package used primarily modify flash filesystem via usb connection host computer requires device started boot loader secondary program loader mode basic hardware initialization performed enabling protocol device accept specific set commands sent via usb using command line commonly used fastboot commands include code written c/c++ compiled arm x86 native code 64-bit variants using android native development kit ndk ndk uses clang compiler compile c/c++ gcc included ndk r17 removed r18 2018 native libraries called java code running android runtime using codice_8 part standard android java classes command-line tools compiled ndk installed using adb android uses bionic c library llvm libc++ c++ standard library ndk also includes variety apis zlib compression opengl es vulkan graphics opensl es audio various android-specific apis things like logging access cameras accelerating neural networks ndk includes support cmake codice_9 based gnu make android studio supports running either gradle third-party tools allow integrating ndk eclipse visual studio cpu profiling ndk also includes simpleperf similar linux perf tool better support android specifically mixed java/c++ stacks android 3.1 platform also backported android 2.3.4 introduces android open accessory support allows external usb hardware android usb accessory interact android-powered device special accessory mode android-powered device accessory mode connected accessory acts usb host powers bus enumerates devices android-powered device acts usb device android usb accessories specifically designed attach android-powered devices adhere simple protocol android accessory protocol allows detect android-powered devices support accessory mode development tools intended help android device interact external electronics include ioio android open accessory development kit microbridge triggertrap etc android :build perl cpan module enables callers build android apk file using basic command line tools aapt dx javac jarsigner zipalign without rely either apache ant gradle reduced dependency set simplifies continuous release systems rely fully automated remote app generation testing july 12 2010 google announced availability app inventor android web-based visual development environment novice programmers based mit open blocks java library providing access android devices gps accelerometer orientation data phone functions text messaging speech-to-text conversion contact data persistent storage web services initially including amazon twitter could done android ’ architecture open said project director mit hal abelson development year block-editing tool taught non-majors computer science harvard mit wellesley trinity college hartford university san francisco professor david wolber developed introductory computer science course tutorial book non-computer science students based app inventor android second half 2011 google released source code terminated web service provided funding creation mit center mobile learning led app inventor creator hal abelson fellow mit professors eric klopfer mitchel resnick latest version created result google–mit collaboration released february 2012 first version created solely mit launched march 2012 upgraded app inventor 2 december 2013 2014 app inventor maintained mit basic4android commercial product similar simple inspired microsoft visual basic 6 microsoft visual studio makes android programming much simpler regular visual basic programmers find coding java difficult basic4android active coreliu enables non-technical users write immersive educational apps run natively android devices app authors use file held github repository describe images text used app speech generated text via amazon web services polly coreliu packages photos generated speech android apk file author distribute freely using creative commons license corona sdk software development kit sdk created walter luh founder corona labs inc.. corona sdk allows software programmers build mobile applications iphone ipad android devices corona lets developers build graphic applications using integrated lua language layered top c++/opengl sdk uses subscription-based purchase model without requiring per-application royalties imposes branding requirements delphi also used creating android application object pascal language latest release delphi 10 seattle developed embarcadero user interfaces developed using cross-platform gui framework firemonkey additionally non-visual components interaction various sensors like camera gyroscope gps bluetooth etc available services access certain keyboard events available platform-independent manner well done using interfaces compiler based llvm architecture debugging ide possible generated apps based ndk contrast xamarin runtime compiled application rapid application development tool developing native android applications using javascript tool used directly mobile device via browser based ide connected device via wifi makes use google chrome v8 javascript engine since version 1.4 go programming language writing applications android supported go version 1.7 help codice_10 tool i.e codice_11 compiling android apk ios apps supported go codebase strictly speaking java/jvm code always needed run android gomobile tool provides minimal jvm code needed objective-c code needed case ios go support restricted go types used currently restricted set android apis e.g openal opengl es 2 bindings provided could used make 2d/3d games one provided examples android ios graphics applications hypernext android creator hac software development system aimed beginner programmers help create android apps without knowing java android sdk based hypercard treated software stack cards one card visible one time well suited mobile phone applications one window visible time hypernext android creator main programming language simply called hypernext loosely based hypercard hypertalk language hypernext interpreted english-like language many features allow creation android applications supports growing subset android sdk including versions gui control types automatically runs background service apps continue run process information background kivy open source python library developing multitouch application software natural user interface nui wide selection devices kivy provides possibility maintaining single application numerous operating systems code run everywhere kivy custom-built deployment tool deploying mobile applications called bulldozer available linux bulldozer currently alpha software far less cumbersome older kivy deployment methods applications programmed kivy submitted android mobile application distribution platform lazarus ide may used develop android applications using object pascal pascal dialects based free pascal compiler starting version 2.7.1 processing environment also uses java language supported android mode since version 1.5 integration device camera sensors possible using ketai library qt android enables qt 5 applications run devices android v2.3.3 api level 10 later qt cross-platform application framework target platforms android linux ios sailfish os windows qt application development done standard c++ qml requiring android ndk sdk qt creator integrated development environment provided qt framework multi-platform application development rubymotion toolchain write native mobile apps ruby version 3.0 rubymotion supports android rubymotion android apps call entire set java android apis ruby use 3rd-party java libraries statically compiled machine code sdl library offers also development possibility beside java allowing development c simple porting existing sdl native c applications injection small java shim jni usage native sdl code possible allowing android ports like e.g jagged alliance 2 video game microsoft shipped 2015 free stand-alone emulator android dubbed visual studio emulator android emulator supports installation google play drag-and-drop interface work conjunction visual studio supports cross-platform development letting c++ developers create projects templates android native-activity applications create high-performance shared libraries include solutions features include platform-specific intellisense breakpoints device deployment emulation c shared codebase developers use xamarin write native ios android windows apps native user interfaces share code across multiple platforms square built lot android based libraries used android applications third party packages popular ones retrofit http calls dagger dependency injection picasso image caching android developer challenge competition find innovative application android google offered prizes totaling 10 million us dollars distributed adc adc ii adc accepted submissions january 2 april 14 2008 50 promising entries announced may 12 2008 received 25,000 award development ended early september announcement ten teams received 275,000 ten teams received 100,000 adc ii announced may 27 2009 first round adc ii closed october 6 2009 first-round winners adc ii comprising top 200 applications announced november 5 2009 voting second round also opened day ended november 25 google announced top winners adc ii november 30 sweetdreams doodle wavesecure nominated overall winners challenge community open-source enthusiasts build share android-based distributions i.e firmware number customizations additional features flac lossless audio support ability store downloaded applications microsd card usually involves rooting device rooting allows users root access operating system enabling full control phone rooting several disadvantages well including increased risk hacking high chances bricking losing warranty increased virus attack risks etc also possible install custom firmware although device boot loader must also unlocked custom firmware allows users older phones use applications available newer releases firmware packages updated frequently incorporate elements android functionality n't yet officially released within carrier-sanctioned firmware tend fewer limitations cyanogenmod omfgb examples firmware september 24 2009 google issued cease desist letter modder cyanogen citing issues re-distribution google closed-source applications within custom firmware even though android os open source phones come packaged closed-source google applications functionality google play gps navigation google asserted applications provided approved distribution channels licensed distributors cyanogen complied google license continued distribute mod without proprietary software provided method backup licensed google applications mod install process restore process complete obstacles development include fact android use established java standards java se prevents compatibility java applications written platforms written android platform android reuses java language syntax semantics provide full class libraries apis bundled java se however multiple tools market companies myriad group upontek provide java android conversion services android provides gui classes provide java awt swing javafx support full java beans api android created open handset alliance led google early feedback developing applications android platform mixed issues cited include bugs lack documentation inadequate qa infrastructure public issue-tracking system google announced issue tracker january 18 2008 december 2007 mergelab mobile startup founder adam macbeth stated functionality poorly documented n't work ... clearly ready prime time despite android-targeted applications began appear week platform announced first publicly available application snake game preview release android sdk released november 12 2007 july 15 2008 android developer challenge team accidentally sent email entrants android developer challenge announcing new release sdk available private download area email intended winners first round android developer challenge revelation google supplying new sdk releases developers others keeping arrangement private led widely reported frustration within android developer community time august 18 2008 android 0.9 sdk beta released release provided updated extended api improved development tools updated design home screen detailed instructions upgrading available already working earlier release september 23 2008 android 1.0 sdk release 1 released according release notes included mainly bug fixes although smaller features added also included several api changes 0.9 version multiple versions released since developed december 5 2008 google announced first android dev phone sim-unlocked hardware-unlocked device designed advanced developers modified version htc dream phone developers use regular consumer devices test use applications developers may choose dedicated unlocked no-contract device one million applications developed android 25 billion downloads june 2011 research indicated 67 mobile developers used platform time publication android smartphone shipments forecast exceed 1.2 billion units 2018 85 market share
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Operating systems
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tcp global synchronization tcp global synchronization computer networks happen tcp/ip flows periods congestion sender reduce transmission rate time packet loss occurs routers internet normally packet queues allow hold packets network busy rather discarding routers limited resources size queues also limited simplest technique limit queue size known tail drop queue allowed fill maximum size new packets simply discarded space queue causes problems used tcp/ip routers handling multiple tcp streams especially bursty traffic present network stable queue constantly full problems except full queue results high latency however introduction sudden burst traffic may cause large numbers established steady streams lose packets simultaneously tcp automatic recovery dropped packets interprets congestion network usually correct sender reduces sending rate certain amount time tries find network longer congested increasing rate subject ramp-up known slow-start algorithm almost senders use time delay increasing rates delays expire time senders send additional packets router queue overflow packets dropped senders back fixed delay ... ad infinitum compare thundering herd problem pattern sender decreasing increasing transmission rates time senders referred global synchronization leads inefficient use bandwidth due large numbers dropped packets must retransmitted senders reduced sending rate compared stable state backed-off following loss problem subject much research consensus appears tail drop algorithm leading cause problem queue size management algorithms random early detection red weighted red reduce likelihood global synchronization well keeping queue sizes face heavy load bursty traffic
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Internet protocols
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rscheme rscheme scheme implementation developed donovan kolbly object-orientation approach adapted dylan rscheme implements r4rs except transcript-on transcript-off r5rs except define-syntax addition rscheme reflective object system many operating system services modules threads systems programming features including ability integrate compile c code code rscheme compiled c c compiled normal c compiler generate machine code default keep compilation fast code size rscheme compiles bytecodes interpreted runtime virtual machine systems compiling c done on-the-fly resulting object code dynamically loaded back image execution rscheme known publicly available scheme implementation include real-time safe garbage collector
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Programming language topics
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great cannon great cannon china attack tool used launch distributed denial-of-service attacks websites intercepting massive amounts web traffic redirecting targeted websites according researchers citizen lab international computer science institute princeton university center information technology policy coined term great cannon hijacks foreign web traffic intended chinese websites re-purposes flood targeted web servers enormous amounts traffic attempt disrupt operations co-located great firewall great cannon separate offensive system different capabilities design besides launching denial-of-service attacks tool also capable monitoring web traffic distributing malware targeted attacks ways similar quantum insert system used u.s. national security agency first known targets great cannon late march 2015 websites hosting censorship-evading tools including github web-based code hosting service greatfire service monitoring blocked websites china
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Computer security
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veryspatial podcast veryspatial podcast award winning weekly podcast provides information geography geospatial technologies podcast comments gis impact digital daily lives podcast seeks cover current trends gis technology industry receives mention industry blogs crew also interviewed directions magazine podcast opens episode number 30-second teaser podsafe song overview topics covered episode following sponsorship ad shout outs go twitter facebook followers hosts discuss 3-4 news items week relevant geography gis including new software releases web site highlighted 'webcorner moving main topic either interview someone industry discussion amongst hosts industry topic show rounds 'tip week highlights technology technique 'eventscorner highlights upcoming geography gis conferences full podsafe song teased beginning episode changes weekly podcast hosted jesse rouse sue bergeron frank lafone podcast started july 2005 since published well 200 weekly episodes numerous special episodes highlight specific topics avsp roadshow episodes cover activity geography gis conferences hosts sue bergeron frank lafone jesse rouse addition barbara maclennan blogs accompanying site veryspatial.com 2007 veryspatial llc parent organization veryspatial podcast awarded esri special achievement gis efforts disseminate information geography geospatial technologies broad audience podcasts blog veryspatial.com episodes licensed creative commons attribution share-alike noncommercial license distributed via direct download veryspatial.com website apple itunes store subscription using zune software common podcast channels download charge source show typically available two formats 64 kbit/s mp3 64 kbit/s aac 25,000 episodes downloaded per month current archived podcasts
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Distributed computing architecture
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runtime callable wrapper runtime callable wrapper rcw proxy object generated .net common language runtime clr order allow component object model com object accessed managed code although rcw appears ordinary object .net clients primary function marshal calls data .net client com object example managed application written c might make use existing com library written c++ visual basic 6 via rcws runtime creates exactly one rcw com object regardless number references exist object runtime maintains single rcw per process object create rcw one application domain apartment pass reference another application domain apartment proxy first object used
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Operating systems
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institute information infrastructure protection institute information infrastructure protection i3p consortium national cyber security institutions including academic research centers u.s. federal government laboratories nonprofit organizations long-standing widely recognized expertise cyber security research development r i3p managed george washington university home small administrative staff oversees helps direct consortium activities i3p coordinates funds cyber security research related critical infrastructure protection hosts high impact workshops bring together leaders public private sectors i3p brings multi-disciplinary multi-institutional perspective complex difficult problems works collaboratively stakeholders seeking solutions since founding 2002 100 researchers wide variety disciplines backgrounds worked together better understand mitigate critical risks field cyber security i3p came existence following several government assessments u.s. information infrastructure ’ susceptibility catastrophic failure first study published 1998 united states president council advisors science technology pcast recommended nongovernmental organization formed address national cyber security issues subsequent studies–by institute defense analyses well white paper jointly produced national security council office science technology policy–agreed pcast assessment affirming need organization dedicated protecting nation ’ critical infrastructures 2002 i3p founded dartmouth college grant federal government martin wybourne chaired i3p 2003 2015 since inception i3p funding i3p come various sources including department homeland security dhs national institute standards technology nist national science foundation nsf i3p consortium consists 18 academic research centers 5 national laboratories 3 nonprofit research organizations member institution appoints primary secondary representative attend regular consortium meetings advanced technological education i3p partnered community college system new hampshire ccsnh educational project “ cybersecurity healthcare industry curriculum adaptation implementation. ” funded national science foundation ’ nsf advanced technological education ate program goal project produce well-qualified technicians serve healthcare information technology needs rural northern new england i3p launched project called improving csirt skills dynamics effectiveness effort funded department homeland security science technology directorate aims explore makes sustains good csirt results help organizations ensure csirts fulfill maximum potential become invaluable tool securing cyber infrastructure interdisciplinary team working new project include cyber security business researchers dartmouth college organizational psychologists george mason university researchers practitioners hewlett-packard april 2011 i3p convened nist-sponsored workshop examining challenge integrating security usability design development software one several workshop recommendations development case studies show software developers usable security integrated organization software development process consequently i3p begun usable security project using uniform study methodology project document usable security three different organizations results used understand key usable security problems addressed teach developers solutions enable researchers perform comparable studies nation critical infrastructure threat cyber attack today never main response cyber threat facing country increased information sharing traditionally agencies store data data bases information readily available others might benefit obama administration made clear strategy work – data must readily available sharing preferred way would using cloud numerous government agencies would store information information would available appropriate credentials model tremendous added benefits – associated risks researchers rand university virginia took challenge answering question information sharing project privacy digital era researchers five i3p academic institutions engaged sweeping effort understand privacy digital era course 18 months research project take multidisciplinary look privacy examining roles human behavior data exposure policy expression way people understand protect privacy leveraging human behavior reduce cyber security risk project brings behavioral-sciences lens security examining interface human beings computers set rigorous empirical studies multi-disciplinary project draws together social scientists information security professionals illuminate intricacies human perceptions cognitions biases impact computer security project ’ goal leverage new insights way produces secure systems processes better security risk pricing i3p researchers project examined ways quantify cyber risk exploring potential multi-factor scoring system analogous risk scoring insurance sector overall work takes account two key determinants cyber risk technologies reduce likelihood attack internal capabilities respond successful potential attacks survivability recovery process control systems research project builds earlier i3p project control-systems security develop strategies enhancing control-system resilience allowing rapid recovery event successful cyber attack business rationale cyber security project offshoot earlier study economics security addresses challenge corporate decision-making comes investing cyber security attempted answer questions “ much needed ” “ much enough ” “ one measure return investment ” study includes investigation investment strategies including risks vulnerabilities supply-chain interdependencies technological fixes safeguarding digital identity multidisciplinary scope project addresses security digital identities emphasizing development technical approaches managing digital identities also meet political social legal needs work focused primarily two sectors privacy identity protection paramount financial services healthcare insider threat project addresses need detect monitor prevent insider attacks inflict serious harm organization researchers undertaken systematic analysis insider threat one addresses technical challenges also takes account ethical legal economic dimensions i3p delivered report titled national cyber security research development challenges industry academic government perspective u.s senators joseph lieberman susan collins february 18 2009 report reflects finding three forums hosted i3p 2008 brought together high-level experts industry government academia identify r opportunities would advance cyber security research next five 10 years report contains specific recommendations technology policy research reflect input participants also concerns public private sectors i3p connects engages stakeholders workshops outreach activities often held partnership organizations workshops encompass range topics directly related i3p research projects others intended bring right people together probe particularly difficult foundational challenge secure systems engineering workforce development i3p sponsored postdoctoral research fellowship program 2004-2011 provides funding year research i3p member institution competitive awards granted according merit proposed work extent proposed work explored creative original concepts potential impact topic u.s. information infrastructure prospective applicants expected address core area cyber security research including trustworthy computing enterprise security management secure systems engineering network response recovery identity management forensics wireless computing metrics well legal policy economic dimensions security
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Computer security
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dos wedge dos wedge popular piece commodore 64 system software written bob fairbairn included commodore cbm 1541 disk drive test/demo disk filename dos 5.1 also packaged c64 macro assembler filename dos wedge64 dos wedge referred 1541 drive manual dos support software startup screen dos manager original design developed bill seiler wedge made disk operations basic 2.0 significantly easier introducing several keyword shortcuts dos wedge became somewhat de facto standard third party vendors epyx often incorporating identical commands fastloader cartridges commodore 64 expansion devices compute gazette published several type-in variations dos wedge including c128 version february 1987 issue see external links original commodore dos wedge 1-kb program written mos 6502 assembly language resided otherwise unused memory block cc00– cfff 52224–53247 worked altering basic chrget subroutine 0073 115 character passing basic interpreter would checked wedge commands associated wedged-in routines run needed command contains symbol may substitute instead desired
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Operating systems
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racket programming language racket general-purpose multi-paradigm programming language based scheme dialect lisp designed platform programming language design implementation addition core racket language racket also used refer family racket programming languages set tools supporting development racket racket also used scripting computer science education research racket platform provides implementation racket language including run-time system libraries jit compiler along drracket integrated development environment ide written racket racket used programbydesign outreach program aims turn computer science indispensable part liberal arts curriculum core racket language known extensive macro system enables creating embedded domain-specific languages language constructs classes modules separate dialects racket different semantics platform distribution free open-source software distributed gnu lesser general public license lgpl extensions packages written community may uploaded racket package catalog matthias felleisen founded plt mid 1990s first research group soon project dedicated producing pedagogic materials novice programmers lectures exercises/projects software january 1995 group decided develop pedagogic programming environment based scheme matthew flatt cobbled together mred original virtual machine racket libscheme wxwidgets free systems years followed team including flatt robby findler shriram krishnamurthi cormac flanagan many others produced drscheme programming environment novice scheme programmers research environment soft typing main development language drscheme supported named plt scheme parallel team began conducting workshops high school teachers training program design functional programming field tests teachers students provided essential clues directing development following years plt added teaching languages algebraic stepper transparent read–eval–print loop constructor-based printer many innovations drscheme producing application-quality pedagogic program development environment 2001 core team felleisen findler flatt krishnamurthi also written published first textbook design programs based teaching philosophy racket manifesto details principles driving development racket presents evaluation framework behind design process details opportunities future improvements first generation plt scheme revisions introduced features programming large modules classes version 42 introduced units – first-class module system – complement classes large scale development class system gained features e.g java-style interfaces also lost several features e.g multiple inheritance throughout versions language evolved throughout number successive versions gaining milestone popularity version 53 leading extensive work following version 100 would equivalent 1.0 release current popular version systems next major revision named version 200 introduced new default module system cooperates macros particular module system ensures run-time compile-time computation separated support tower languages unlike units modules first-class objects version 300 introduced unicode support foreign library support refinements class system later 300 series improved performance language runtime addition jit compiler switch default generational garbage collection next major release project switched conventional sequence-based version numbering version 4.0 introduced codice_1 shorthand specify language module written revision introduced immutable pairs lists support fine-grained parallelism statically-typed dialect june 7 2010 plt scheme renamed racket renaming coincided release version 5.0 subsequently graphical user interface gui backend rewritten racket c++ version 5.1 using native ui toolkits platforms version 5.2 included background syntax checking tool new plotting library database library new extended repl version 5.3 included new submodule feature optionally loaded modules new optimization tools json library features version 5.3.1 introduced major improvements drracket background syntax checker turned default new documentation preview tool added version 6.0 racket released second-generation package management system part development principal drracket racket repository reorganized split large set small packages making possible install minimal racket install packages needed version 7 racket released new macro expander written racket part preparations supporting moving chez scheme runtime system supporting multiple runtime systems racket core language includes macros modules lexical closures tail calls delimited continuations parameters fluid variables software contracts green os threads language also comes primitives eventspaces custodians control resource management enables language act like operating system loading managing programs extensions language created powerful macro system together module system custom parsers control aspects language unlike programming languages lack macro systems language constructs racket written base language using macros include mixin class system component module system expressive ml opaque ascription pattern matching language features first contract system higher-order programming language racket contract system inspired design contract work eiffel extends work higher-order values first-class functions objects reference cells example object checked contract ensured make contract checks methods eventually invoked racket includes bytecode jit jit compilers bytecode compiler translates internal bytecode format run racket virtual machine jit compiler translating bytecode native code x86 x86-64 arm powerpc platforms runtime since 2004 language also shipped planet package manager integrated module system third-party libraries transparently imported used also planet built-in versioning policy prevent dependency hell end 2014 much racket code moved new packaging system separate main code base new packaging system serviced client program named raco new package system provides fewer features planet blog post jay mccarthy racket blog explains rationale change duplicate older system features clearly distinguish racket languages lisp family integrated language extensibility features support building new domain-specific general-purpose languages racket extensibility features built module system allow context-sensitive module-level control syntax example codice_2 syntactic form overridden change semantics function application similarly codice_3 form allows arbitrary static analysis entire module since module used language via codice_1 notation effectively means virtually aspect language programmed controlled module-level extensibility features combined scheme-like hygienic macro system provides features lisp s-expression manipulation system scheme 84 hygienic extend-syntax macros r5rs syntax-rules indeed fair say macro system carefully tuned application programming interface api compiler extensions using compiler api programmers add features entire domain-specific languages manner makes completely indistinguishable built-in language constructs macro system racket used construct entire language dialects includes typed racket gradually typed dialect racket eases migration untyped typed code lazy racket—a dialect lazy evaluation hackett combines haskell racket pedagogical programming language pyret originally implemented racket. ref name= index 2017 /ref dialects include frtime functional reactive programming scribble documentation language slideshow presentation language several languages education racket core distribution provides libraries aid process constructing new programming languages languages restricted s-expression based syntax addition conventional readtable-based syntax extensions racket codice_1 makes possible language programmer define arbitrary parser example using parser tools library see racket logic programming example language language platform provides self-hosted ide named drracket continuation-based web server graphical user interface tools racket also viable scripting tool used scripting unix shell parse command line arguments execute external tools includes libraries like common scripting languages drracket formerly drscheme widely used among introductory computer science courses teach scheme racket lauded simplicity appeal beginner programmers ide originally built use teachscheme project programbydesign outreach effort northeastern university number affiliated universities attracting high school students computer science courses college level editor provides source highlighting syntax run-time errors parenthesis matching debugger algebraic stepper student-friendly features include support multiple language levels beginning student intermediate student also integrated library support sophisticated analysis tools advanced programmers module-oriented programming supported module browser contour view integrated testing coverage measurements refactoring support provides integrated context-sensitive access extensive hyper-linked help system named help desk drracket available windows macos unix linux x window system programs behave similarly platforms trivial hello world program running program produces output slightly less trivial program program taken racket website draws sierpinski triangle nested depth 8 using codice_1 directive source file written different dialects racket example factorial program typed racket statically typed dialect racket apart basis programming language theory racket designed used general-purpose language production systems thus racket distribution features extensive library covers systems network programming web development uniform interface underlying operating system dynamic foreign function interface several flavours regular expressions lexer/parser generators logic programming complete gui framework racket several features useful commercial language among ability generate standalone executables windows macos unix profiler debugger included integrated development environment ide unit testing framework racket used commercial projects web applications notable example hacker news website runs arc developed racket naughty dog used scripting language several video games racket used teach students algebra game design bootstrap program
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Programming language topics
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openmusic openmusic om object-oriented visual programming environment musical composition based common lisp may also used all-purpose visual interface lisp programming specialized level set provided classes libraries make convenient environment music composition openmusic last series computer-assisted composition software designed ircam versions openmusic currently available mac os x powerpc intel windows linux source code released gnu lesser general public license lgpl programs openmusic created connecting together process known 'patching either pre-defined user-defined modules similar manner graphical signal-processing environments max/msp pd unlike environments however result openmusic computation typically displayed conventional music notation directly manipulated required via editor substantial body specialized libraries contributed users extends openmusic functionality areas constraint programming aleatoric composition spectral music minimalist music music theory fractals music information retrieval sound synthesis etc
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Programming language topics
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virtual concatenation virtual concatenation vcat inverse multiplexing technique creating large capacity payload container distributed multiple smaller capacity tdm signals signals may transported routed independently virtual concatenation defined sonet/sdh otn pdh path signals alternate sonet/sdh concatenation techniques contiguous concatenation arbitrary concatenation virtual concatenation considered primary enhancement voice optimized sonet/sdh order support transport variable bit data streams recent sonet/sdh enhancements include link capacity adjustment scheme lcas generic framing procedure gfp conjunction lcas gfp virtual concatenation gives advantage splitting required bandwidth equally among set number sub paths called virtual tributaries vt virtual concatenation specified itu-t recommendations g.707 2007 g.783 2006 virtual concatenation used split sonet/sdh bandwidth right-sized groups virtually concatenated groups used support different customers services bill accordingly vcat works across existing infrastructure significantly increase network utilization effectively spreading load across whole network sonet/sdh hierarchical network level payloads concatenation lower-order payloads example sts192 10 gbit/s payload consists four oc48 2.5 gbit/s payloads concatenated together vcat sts192 payload could consist number virtually concatenated groups 192 non-contiguous sts1 51 mbit/s payloads sts1 within group may provisioned different parts network vcat supports high-order paths low-order tributary paths path within group approximately 51 mbit/s sts1/vc3 155 mbit/s sts3c/vc4 bandwidth allocated using h4 byte within path overhead bandwidth allocated multiples 51 mbit/s therefore high-order vcat used provision sub-rate traffic across gigabit ethernet makes high-order vcat ideal metro application path within group approximately 1.5 mbit/s vt1.5/vc11 2 mbit/s vt2/vc12 bandwidth allocated using z7/k4 byte within path overhead bandwidth allocated 2-mbit/s chunks therefore low-order vcat used provision sub-rate traffic across 10/100-mbit/s ethernet used access network several virtual tributaries form part virtual concatenation group vcg virtual tributaries transport data across vcat enabled network may many cases particularly underlying network relatively congested cost less finding one path meets required capacity splitting paths often finds shorter paths channel traffic virtual concatenation protocol performs content delivery process called byte-interleaving example given wish provision gigabit ethernet n 1gbit/s service would provision across 7 sts-nc vt ’ vcg members carry bandwidth equivalent v n/k bits/second case n 1gb k 7 typically happens data interleaved first byte put onto vt1 second byte put onto vt2 seventh byte put onto vt7 process repeats beginning eighth byte sent vt1 vcat helps providing services lower cost quickly contiguous concatenation however creates differential delay whereby path created represented vt different propagational delay across network difference delays called differential delay major problem differential delay requirement high speed buffers receiving node store incoming information paths converge buffer space b equated bandwidth delay product b n d. thus virtually concatenated connection requires b bits buffer space need buffer space eventually increases network cost important select paths minimize differential delay directly proportional buffer space required several heuristics based algorithms exist attempt minimize differential delay provide solution simple problem tackle referred mathematically np-complete problem set exists known algorithm finds optimum solution terminates polynomial time constraint
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Internet protocols
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cursor databases computer science database cursor control structure enables traversal records database cursors facilitate subsequent processing conjunction traversal retrieval addition removal database records database cursor characteristic traversal makes cursors akin programming language concept iterator cursors used database programmers process individual rows returned database system queries cursors enable manipulation whole result sets scenario cursor enables sequential processing rows result set sql procedures cursor makes possible define result set set data rows perform complex logic row row basis using mechanics sql procedure also define result set return directly caller sql procedure client application cursor viewed pointer one row set rows cursor reference one row time move rows result set needed use cursors sql procedures need following work cursors must use following sql statements section introduces ways standard defines use cursors applications embedded sql application bindings relational database systems adhere standard cli jdbc use different interface programmer makes cursor known dbms using codice_1 ... codice_2 statement assigning cursor compulsory name code access data must open cursor codice_3 statement directly following successful opening cursor positioned first row result set applications position cursors specific row result set codice_4 statement fetch operation transfers data row application application processed available rows fetch operation positioned non-existing row compare scrollable cursors dbms returns sqlstate '02000 usually accompanied +100 indicate end result set final step involves closing cursor using codice_5 statement closing cursor program open implies dbms re-evaluates query different query builds new result set programmers may declare cursors scrollable scrollable scrollability indicates direction cursor move non-scrollable forward-only cursor codice_4 row cursor automatically moves next row fetch last row fetch put cursor last row get following code sqlstate 02000 sqlcode +100 program may position scrollable cursor anywhere result set using codice_4 sql statement keyword scroll must specified declaring cursor default codice_8 although different language bindings like jdbc may apply different default target position scrollable cursor specified relatively current cursor position absolutely beginning result set scrollable cursors potentially access row result set multiple times thus data modifications insert update delete operations transactions could affect result set cursor sensitive insensitive data modifications sensitive cursor picks data modifications affecting result set cursor insensitive cursor additionally cursor may insensitive case dbms tries apply sensitivity much possible cursors usually closed automatically end transaction i.e commit rollback implicit termination transaction occurs behavior changed cursor declared using hold clause default without hold holdable cursor kept open commit closed upon rollback dbms deviate standard behavior also keep holdable cursors open rollback commit occurs holdable cursor positioned next row thus positioned update positioned delete statement succeed fetch operation occurred first transaction note jdbc defines cursors holdable per default done jdbc also activates auto-commit per default cursors used fetch data dbms application also identify row table updated deleted sql:2003 standard defines positioned update positioned delete sql statements purpose statements use regular clause predicates instead cursor identifies row cursor must opened already positioned row means codice_4 statement cursor must operate updatable result set order successfully execute positioned update delete statement otherwise dbms would know apply data changes underlying tables referred cursor using cursors distributed transactions x/open xa environments controlled using transaction monitor different cursors non-distributed transactions one pay attention using holdable cursors however connections used different applications thus transaction ended committed subsequent transaction running different application could inherit existing holdable cursors herefore application developer aware situation xquery language allows cursors created using subsequence function format result result initial xquery start item number start item-count number items return equivalently also done using predicate codice_10 end sequence complete examples see following information may vary depending specific database system fetching row cursor may result network round trip time uses much network bandwidth would ordinarily needed execution single sql statement like delete repeated network round trips severely reduce speed operation using cursor dbmss try reduce effect using block fetch block fetch implies multiple rows sent together server client client stores whole block rows local buffer retrieves rows buffer exhausted cursors allocate resources server locks packages processes temporary storage example microsoft sql server implements cursors creating temporary table populating query result set cursor properly closed deallocated resources freed sql session connection closed wasting resources server lead performance degradations failures employees table
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Databases
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j programming language j programming language developed early 1990s kenneth e. iverson roger hui synthesis apl also iverson fp fl function-level languages created john backus avoid repeating apl special-character problem j uses basic ascii character set resorting use dot colon inflections form short words similar digraphs primary primitive j words serve mathematical symbols dot colon extending meaning basic characters available also many characters languages often must paired codice_1 codice_2 treated j stand-alone words inflected single-character roots multi-character words j terse array programming language suited mathematical statistical programming especially performing operations matrices also used extreme programming network performance analysis like original fp/fl languages j supports function-level programming via tacit programming features unlike languages support object-oriented programming j flexible hierarchical namespace scheme every name exists specific locale effectively used framework class-based prototype-based object-oriented programming since march 2011 j free open-source software gnu general public license version 3 gplv3 one may also purchase source negotiated license j permits point-free style function composition thus programs terse considered difficult read programmers hello world program j implementation hello world reflects traditional use j – programs entered j interpreter session results expressions displayed also possible arrange j scripts executed standalone programs might look unix system historically apl used codice_3 indicate fold codice_4 equivalent codice_5 meanwhile division represented classic mathematical division symbol obelus ÷ implemented overstriking minus sign colon ebcdic ascii paper text terminals ascii general support overstrikes device-independent way include division symbol per se j uses represent division visual approximation reminder illustrates something mnemonic character j tokens quandaries imposed use ascii defining j function named codice_6 calculate average list numbers yields test execution function codice_7counts number items array.codice_8sums items array.codice_9divides sum number items avg defined using train three verbs codice_10 codice_11 codice_12 termed fork specifically codice_13 codice_14 shows power j v0 v1 v2 denote verbs ny denotes noun examples using codice_6 rank crucial concept j significance j similar significance codice_16 sql codice_17 c. implementing quicksort j dictionary yields following implementation quicksort demonstrating tacit programming later involves composing functions together referring explicitly variables j support forks hooks dictates rules arguments applied function applied component functions sorting j usually accomplished using built-in primitive verbs codice_18 sort codice_19 sort user-defined sorts quicksort typically illustration following example demonstrates usage self-reference verb codice_20 recursively calculate fibonacci numbers recursion also accomplished referring verb name although course possible verb named following expression exhibits pi n digits demonstrates extended precision abilities j j supports three simple types numeric variants one j numeric types bit two bit values 0 1 also bits formed lists example codice_21 list eight bits syntactically j parser treats one word space character recognized word-forming character would otherwise numeric words lists arbitrary length supported j supports usual binary operations lists exclusive rotate shift etc example j also supports higher order arrays bits formed two-dimensional three-dimensional etc arrays operations perform equally well arrays numeric types include integer e.g. 3 42 floating point 3.14 8.8e22 complex 0j1 2.5j3e88 extended precision integer 12345678901234567890x extended precision rational fraction 1r2 3r4 bits formed lists arbitrarily dimensioned arrays bits operations performed numbers array lists bits converted integer using codice_22 verb integers converted lists bits using codice_23 verb parsing j codice_24 period codice_25 colon word-forming characters never tokens alone unless preceded whitespace characters j also supports literal character type literals enclosed quotes example codice_26 codice_27 lists literals also supported using usual convention putting multiple characters quotes codice_28 typically individual literals 8-bits wide ascii j also supports literals unicode numeric boolean operations supported literals collection-oriented operations rotate supported finally boxed data type typically data put box using codice_29 operation left argument left argument would less operation analogous c codice_30 operation left argument however result c codice_30 reference semantics result j codice_29 value semantics words codice_29 function produces result result 0 dimensions regardless structure contained data viewpoint j programmer codice_29 puts data box allows working array boxes assembled boxes and/or copies made box collection type offered j arbitrarily dimensioned array algorithms expressed concisely using operations arrays j arrays homogeneously typed example list codice_35 list integers despite codice_36 bit part sorts type issues transparent programmers certain specialized operations reveal differences type example list codice_37 would treated exactly operations list codice_38 j also supports sparse numeric arrays non-zero values stored indices efficient mechanism relatively values non-zero j also supports objects classes artifact way things named data types instead boxed literals used refer objects classes j data value semantics objects classes need reference semantics another pseudo-type—associated name rather value—is memory mapped file j documentation includes dictionary words j identified nouns verbs modifiers primary words listed vocabulary respective parts speech indicated using markup note verbs two forms monadic arguments right dyadic arguments left right example 'codice_39 hyphen monadic verb 'codice_40 hyphen dyadic verb monadic definition mostly independent dyadic definition regardless whether verb primitive verb derived verb j provides control structures details similar procedural languages prominent control words category include
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Programming language topics
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parrot os parrot linux linux distribution based debian focus computer security designed penetration testing vulnerability assessment mitigation computer forensics anonymous web browsing developed frank ruben aqua skid parrotsec intended provide suite penetration testing tools used attack mitigation security research forensics vulnerability assessment parrot based debian testing branch buster custom linux 4.19 kernel follows rolling release development model desktop environment mate default display manager lightdm project certified run devices minimum 256mb ram suitable 32-bit i386 64-bit amd64 processor architectures moreover project available armv7 armhf architectures even offers edition 32-bit 64-bit developed specifically servers carry cloud service penetration testing june 2017 parrotsec announced considering change debian devuan mainly problems highly controversial systemd january 21st 2019 parrot linux team phasing development 32-bit i386 versions future operating systems parrot multiple editions based upon debian various desktop environments available parrot home special edition parrot designed daily use targets regular users need lightweight always updated beautiful system laptops workstations distribution look feel regular parrot environment includes basic programs daily work parrot home also includes programs chat privately people encrypt documents highest cryptographic standards surf net completely anonymous secure way system also used starting point build customized pentesting platform tools need use build professional workstation taking advantage latest powerful technologies debian without hassle lightweight parrot release embedded systems aimed simplicity portability supported hardware brands raspberry pi orange pi pine64 cubieboard development team specified official release timeline based release changelogs notes included official review distribution project released monthly basis
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Computer security
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cmd file cp/m cp/m-86 concurrent cp/m-86 personal cp/m-86 s5-dos dos plus concurrent dos flexos multiuser dos system manager real/32 well scp1700 cp/k k8918-os cmd filename extension used cp/m-style executable programs corresponds com cp/m-80 exe dos extension used command-line interpreter cmd.exe os/2 windows batch files cmd file 128-byte header followed 1-8 groups code data group 1 megabyte size later versions format cmd files also contain relocation information resident system extensions rsxs start header lists groups present file types type used first 256 bytes data group must zero populated cp/m-86 zero page comparable program segment prefix dos data group first 256 bytes code group used instead os/2 windows nt .cmd file extension associated batch scripts command processor cmd.exe since binary code executed way attempting run cp/m-86 cmd files cmd command processor work typically cause mild inconvenience users executable loader relocator cp/m-86 related operating systems test first byte file happens type byte first table entry cp/m cmd file value 1 9 accepting valid cp/m cmd file ascii values smaller 10 rarely never used batch scripts scheme gives reasonably good protection
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Operating systems
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cocoa touch cocoa touch ui framework building software programs run ios iphone ipod touch ipad watchos apple watch tvos fourth-generation apple tv apple inc. cocoa touch provides abstraction layer ios operating system iphone ipod touch ipad cocoa touch based macos cocoa api toolset like primarily written objective-c language cocoa touch allows use hardware features found macos computers thus unique ios range devices like cocoa cocoa touch follows model-view-controller mvc software architecture cocoa touch contains different set graphical control elements cocoa tools developing applications based cocoa touch included ios sdk ios watchos tvos technologies seen set layers cocoa touch highest level core os/kernel bottom hierarchical view ios watchos tvos technologies shown follows main features technologies cocoa touch cocoa touch provides key frameworks developing applications devices running ios key frameworks
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Operating systems
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scramble spirits player starts propelled plane fire air-to-air twin machine guns air-to-ground rockets weapons used destroying waves enemy planes ground sea units main plane destroyed one hit certain enemy destroyed player collect comrade fighter fight alongside main plane two comrade fighters collected comrade fighters assigned fight air fire bullets assigned fight low altitude fire air-to-ground rockets comrade fighters also launched kamikaze attack explosion enemy kamikaze attacks comrade fighters retrievable lost shot crash enemy areas certain stages player fly lower altitude armed twin machine guns shooting parked planes turrets take limited amount damage multiple shots crashes end stage player must destroy boss vehicle proceed
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Computer architecture
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thomas w. reps thomas w. reps born 28 may 1956 united states american computer scientist known contributions automatic program analysis dr. reps professor computer science computer sciences department university wisconsin–madison joined 1985 reps author co-author four books one hundred seventy-five papers describing research work covered wide variety topics including program slicing data-flow analysis pointer analysis model checking computer security instrumentation computer programming language-based program-development environments use program profiling software testing software renovation incremental algorithms attribute grammars reps ’ current work focuses static analysis stripped binary executables methods that—without relying symbol-table debugging information—recover intermediate representations similar intermediate phases compiler creates program written high-level language goal provide disassembler decompiler platform analyst use understand workings cots components plugins mobile code dlls well memory snapshots worms virus-infected code reps president co-founder grammatech inc. reps recipient following awards
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Programming language topics
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quartz graphics layer apple macos operating system quartz quartz 2d quartz compositor part core graphics framework quartz includes 2d renderer core graphics composition engine sends instructions graphics card vertical nature quartz often synonymous core graphics general sense quartz quartz technologies refer almost every part graphics model rendering layer compositor including core image core video apple graphics technologies use quartz prefix include quartz 2d primary two-dimensional 2d text graphics rendering library directly supports aqua displaying two-dimensional graphics create user interface including on-the-fly rendering anti-aliasing quartz render text sub-pixel precision graphics limited traditional anti-aliasing default mode operation turned mac os x 10.4 tiger apple introduced quartz 2d extreme enabling quartz 2d offload rendering compatible gpus however gpu rendering enabled default due potential video redraw issues kernel panics mac os x v10.5 quartz 2d extreme renamed quartzgl however still remains disabled default situations degrade performance experience visual glitches per-application setting turned developer wishes quartz compositor compositing engine used macos mac os x jaguar later quartz compositor use graphics accelerator gpu vastly improve composition performance technology known quartz extreme enabled automatically systems supported graphics cards widely stated quartz uses pdf internally notably apple 2000 macworld presentation quartz early developer documentation often people making comparisons display postscript technology used nextstep openstep descendant quartz internal imaging model correlates well pdf object graph making easy output pdf multiple devices
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Operating systems
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neil schwartzman neil schwartzman canadian anti-spam activist involved anti-spam efforts since 1995 co-founder executive director cauce sat canadian federal task force spam u.s. federal communications commission csric network abuse protection working group currently chair m3aawg awards committee
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Computer security
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nowsecure nowsecure formerly viaforensics chicago-based mobile security company publishes mobile app device security software former ceo co-founder andrew hoog working cio one employees dismissed dismissal hoog tasked reviewing whether employee stolen sensitive data company rather hire forensics firm investigate hoog performed investigation continued forensic work side hoog wife chee-young kim contributed money start company originally known chicago electronic discovery viaforensics hoog devoted full-time mobile forensics kim continued work corporate job day participated business development night weekends march 2011 viaforensics profitable extent could pay employee benefits kim left job went work viaforensics full-time june 5 year viaextract 1.0 released conference myrtle beach viaforensics introduced known vialab march 2013. vialab product allowed automated testing variety security flaws apps including man-in-the-middle attacks ssl strip attacks coding problems opportunities reverse engineering viaforensics subject inc 5000 13 fastest-growing tech company us award 2014 2014 viaforensics launched viaprotect app show users destinations sources data mobile devices rsa conference company began focus similar individual enterprise device protection result focus shift viaforensics decided rebrand nowsecure nowsecure publisher nowsecure forensics formerly viaextract nowsecure lab formerly vialab nowsecure mobile apps formerly viaprotect nowsecure forensics designed law enforcement extract artifacts mobile devices applying deleted data recovery data search nowsecure lab mobile app vulnerability scanning software nowsecure mobile free end-user oriented vulnerability scanner ios android blackphone 2014 2015 pc magazine awarded viaprotect editor choice android privacy utilities
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Computer security
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exchange activesync exchange activesync commonly known eas proprietary protocol designed synchronization email contacts calendar tasks notes messaging server smartphone mobile devices protocol also provides mobile device management policy controls protocol based xml mobile device communicates http https originally branded airsync supporting microsoft exchange servers pocket pc devices microsoft licenses technology widely synchronization groupware mobile devices number competing collaboration platforms including addition support windows phone eas client support included beyond premises installations exchange various personal enterprise hosted services microsoft also utilize eas including outlook.com office 365 built-in email application windows 8 desktop mail app also supports protocol apart eas client support included first version eas called airsync time part mobile information server mis 2002 version eas communicated web-based distributed authoring versioning webdav exchange 2000 servers syncing email contacts calendar allowed users select folder list sync email folders contacts calendars initial version eas user ’ device “ pull ” data rather server “ push ” new information soon available eas 2.0 shipped exchange server 2003 version protocol developed microsoft windows mobile team delivered binary drop massync.dll exchange server team eas used webdav connect user mailbox added ability sync non-default calendar contacts folders always date autd implemented way let device know new information short message service sms technology used deliver information device use sms notification configuration sms gateway required account needed configured user mobile phone number exchange server 2003 sp1 ghosting support added eas 2.1 ghosting tells server sync sent changes sent specified fields changed others deleted eas protocol also moved globally unique identifier guid 1 x short ids items reduced amount data sent across wireless network eas 2.5 part exchange server 2003 sp2 first version eas written exchange server team version also introduced direct push real-time push e-mail solution allows server say new item tells client device sync called ping sync global address list gal search added enable people look co-workers company directory find email address ability remotely wipe device also added administrators could remove company data device lost stolen employee left company tasks syncing added s/mime email encryption following policies added eas 12.0 came exchange server 2007 eas 12.0 complete re-write protocol managed code previous version new features included password reset allowed users reset forgotten pin lock code message flagging gave users ability mark message could remember follow got back computer office setting users could set “ away ” message phone sharepoint unc file share access links email file traffic proxied though eas empty deleted items allow people shrink mailboxes ’ exceed mailbox size limits fetch allowed users get parts message choose later get rest message attachment later device info allowed users administrators see phones connected accounts autodiscover although strictly speaking ’ part eas protocol allowed phones automatically configure eas connection user login password instead requiring people know computer name exchange server ability see invited meeting also added well ability search server email synced device new policies introduced eas 12.1 came exchange server 2007 sp1 version protocol one largest changes since version 2.5 featured header compression base64 encoding binary structure decrease amount data sent wirelessly multiple collections sync bundling sync requests together instead previous way sync folder separately hanging sync allowed server keep communications channel open client times battery life data ’ consumed constantly turning radio querying server “ true push sync ” solution far lower message delivery latencies opposed previous ping based “ push pull ” solution confirmation completed remote wipe well following 30 new policies eas 14.0 introduced part exchange server 2010 new version added new conversation view put email messages view connected several attributes including message-id email subject notes syncing ability look availability free/busy status contact calendar nickname cache shared names common used contacts outlook web app owa eas ability set server side rule always move messages conversation lunar calendar support syncing reply state let device server know message forwarded replied source new way identify unified messaging um messages voicemail appeared user ’ inbox could handled differently sms syncing allowed users see sms messages email inbox reply inbox instead phone following two new policies also first version eas identified clients using older versions eas alerted updated version client would enable newer features eas 14.1 came part exchange server 2010 sp1 version protocol added gal photos images stored active directory server user sent email message diffs means sending new portion email avoiding redundant information added device/user information provision command new allow/block/quarantine feature could easily allow administrators control devices connected organizations information rights management irm eas method apply digital rights management control encryption email messages sent received eas 14.1 may allow irm eas eas 16.0 announced june 2015 deployed office 365 first followed exchange server 2016 new protocol version adds mainly 3 enhancements redesigned calendar synchronisation avoid common eas calendar syncing problems added calendar attachments syncing email drafts folder eas 16.1 announced june 2016 deployed office 365 first followed exchange server 2016 version protocol contains three major capabilities improved keyword search propose new time account-only remote wipe beginning early 2000s eas began available licensing time client protocol license motorola first licensee began license 2.1 version eas various organizations licensed eas time microsoft eventually started licensing server side eas 2007 protocol licensing continued 2008 december 2008 microsoft shifted licensing eas protocol license licensing patents eas providing full protocol documentation eas licensed series patents given computer code companies different clients servers implement subset entire features protocol implementations written company obtained license google uses implementation eas g suite subscribers likewise ibm novell implemented technology allow competing groupware servers lotus domino novell groupwise support smartphones devices ibm notes traveler novell data synchronizer mobility pack respectively april 2011 microsoft launched eas logo program tests third-party eas clients mobile email devices handset manufacturers licensed eas protocol microsoft eligible join program order compliant eas clients must employ eas v14.0 later enable following features management policies
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Internet protocols
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quantum programming quantum programming process assembling sequences instructions called quantum programs capable running quantum computer quantum programming languages help express quantum algorithms using high-level constructs quantum instruction sets used turn higher level algorithms physical instructions executed quantum processors sometimes instructions specific given hardware platform e.g ion traps superconducting qubits cqasm also known common qasm hardware-agnostic qasm guarantees interoperability quantum compilation simulation tools introduced qca lab tudelft quil instruction set architecture quantum computing first introduced shared quantum/classical memory model introduced robert smith michael curtis william zeng practical quantum instruction set architecture many quantum algorithms including quantum teleportation quantum error correction simulation optimization algorithms require shared memory architecture openqasm intermediate representation introduced ibm use qiskit ibm q experience blackbird quantum instruction set intermediate representation used xanadu strawberry fields designed represent continuous-variable quantum programs run photonic quantum hardware quantum software development kits provide collections tools create manipulate quantum programs also provide means simulate quantum programs prepare run using cloud-based quantum devices following software development kits used run quantum circuits prototype quantum devices well simulators ocean open source suite tools developed d-wave written mostly python programming language enables user formulate problems ising model quadratic unconstrained binary optimization formats qubo results obtained submitting online quantum computer leap d-wave ’ real-time quantum application environment customer-owned machines classical samplers open source project developed institute theoretical physics eth uses python programming language create manipulate quantum circuits results obtained either using simulator sending jobs ibm quantum devices open source project developed ibm quantum circuits created manipulated using python swift java results obtained either using simulators run user device simulators provided ibm prototype quantum devices provided ibm well ability create programs using basic quantum operations higher level algorithms available within qiskit aqua package qiskit based openqasm standard representing quantum circuits support pulse level control quantum systems specified openpulse standard open source project developed rigetti uses python programming language create manipulate quantum circuits results obtained either using simulators prototype quantum devices provided rigetti well ability create programs using basic quantum operations higher level algorithms available within grove package forest based quil instruction set public access quantum devices currently planned following sdks yet implemented project developed microsoft part .net framework quantum programs written run within visual studio vscode open source project developed google uses python programming language create manipulate quantum circuits results obtained using simulators run user device open-source python library developed xanadu designing simulating optimizing continuous variable cv quantum optical circuits three simulators provided one fock basis one using gaussian formulation quantum optics one using tensorflow machine learning library quantum programming environment developed cambridge quantum computing target simulators quantum hardware planned use hardware produced nqit hub well oxford quantum circuits full release expected september 2018 two main groups quantum programming languages imperative quantum programming languages functional quantum programming languages prominent representatives imperative languages qcl lanq q|si quantum computation language qcl one first implemented quantum programming languages important feature qcl support user-defined operators functions syntax resembles syntax c programming language classical data types similar primitive data types c. one combine classical code quantum code program quantum pseudocode proposed e. knill first formalized language description quantum algorithms introduced moreover tightly connected model quantum machine called quantum random access machine qram language developed microsoft used quantum development kit q|si platform embedded .net language supporting quantum programming quantum extension while-language platform includes compiler quantum while-language chain tools simulation quantum computation optimisation quantum circuits termination analysis quantum programs verification quantum programs q language second implemented imperative quantum programming language q language implemented extension c++ programming language provides classes basic quantum operations like qhadamard qfourier qnot qswap derived base class qop new operators defined using c++ class mechanism quantum memory represented class qreg qreg x1 // 1-qubit quantum register initial value 0 qreg x2 2,0 // 2-qubit quantum register initial value 0 computation process executed using provided simulator noisy environments simulated using parameters simulator quantum guarded command language qgcl defined p. zuliani phd thesis based guarded command language created edsger dijkstra described language quantum programs specification quantum macro assembler qmasm low-level language specific quantum annealers d-wave efforts underway develop functional programming languages quantum computing functional programming languages well-suited reasoning programs examples include selinger qpl haskell-like language qml altenkirch grattage higher-order quantum programming languages based lambda calculus proposed van tonder selinger valiron arrighi dowek qfc qpl two closely related quantum programming languages defined peter selinger differ syntax qfc uses flow chart syntax whereas qpl uses textual syntax languages classical control flow operate quantum classical data selinger gives denotational semantics languages category superoperators qml haskell-like quantum programming language altenkirch grattage unlike selinger qpl language takes duplication rather discarding quantum information primitive operation duplication context understood operation maps formula_1 formula_2 confused impossible operation cloning authors claim akin sharing modeled classical languages qml also introduces classical quantum control operators whereas languages rely classical control operational semantics qml given terms quantum circuits denotational semantics presented terms superoperators shown agree operational denotational semantics implemented classically haskell liqui| pronounced liquid quantum simulation extension f programming language currently developed quantum architectures computation group quarc part stationq efforts microsoft research liqui| seeks allow theorists experiment quantum algorithm design physical quantum computers available use includes programming language optimization scheduling algorithms quantum simulators liqui| used translate quantum algorithm written form high-level program low-level machine instructions quantum device quantum lambda calculi extensions classical lambda calculus introduced alonzo church stephen cole kleene 1930s purpose quantum lambda calculi extend quantum programming languages theory higher-order functions first attempt define quantum lambda calculus made philip maymin 1996 lambda-q calculus powerful enough express quantum computation however language efficiently solve np-complete problems therefore appears strictly stronger standard quantum computational models quantum turing machine quantum circuit model therefore maymin lambda-q calculus probably implementable physical device 2003 andré van tonder defined extension lambda calculus suitable proving correctness quantum programs also provided implementation scheme programming language 2004 selinger valiron defined strongly typed lambda calculus quantum computation type system based linear logic quipper published 2013 implemented embedded language using haskell host language reason quantum programs written quipper written haskell using provided libraries example following code implements preparation superposition
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Programming language topics
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database application database application computer program whose primary purpose entering retrieving information computerized database early examples database applications accounting systems airline reservations systems sabre developed starting 1957 characteristic modern database applications facilitate simultaneous updates queries multiple users systems 1970s might accomplished user front 3270 terminal mainframe computer mid-1980s becoming common give user personal computer program running pc connected database server information would pulled database transmitted network arranged graphed otherwise formatted program running pc starting mid-1990s became common build database applications web interface rather develop custom software run user pc user would use web browser program every application database application web interface advantage could used devices different sizes different hardware different operating systems examples early database applications web interfaces include amazon.com used oracle relational database management system photo.net online community whose implementation top oracle described book database-backed web sites ziff-davis press may 1997 ebay also running oracle electronic medical records referred emrexperts.com december 2010 software database application 2005 o'reilly book uses term title database applications web complex database applications remain accounting systems sap may contain thousands tables single module many today widely used computer systems database applications example facebook built top mysql etymology phrase database application comes practice dividing computer software systems programs operating system compilers file system tools database management system application programs payroll check processor standard pc running microsoft windows example windows operating system contains systems programs games word processors spreadsheet programs photo editing programs etc would application programs application short application program database application short database application program every program uses database would typically considered database application example many physics experiments e.g. large hadron collider generate massive data sets programs subsequently analyze data sets constitute database though typically managed standard relational database management system computer programs analyze data primarily developed answer hypotheses put information back database therefore overall program would called database application
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Databases
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constructed product result analysis field compiler implementation computer science constructed product result analysis cpr analysis static analysis determines functions given program return multiple results efficient manner typically means returning multiple results register opposed returning pointer tuple allocated heap whose components function multiple return values cpr analysis introduced context compiling haskell lazy functional language implemented glasgow haskell compiler may applicable programming languages well
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Programming language topics
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barrett brown barrett lancaster brown born august 14 1981 american journalist essayist satirist founded project pm research collaboration wiki facilitate analysis troves hacked emails leaked information concerning inner workings cyber-military-industrial complex january 2015 brown sentenced 63 months federal prison crimes accessory fact obstruction justice threatening federal officer stemming fbi investigation 2012 stratfor email leak prosecutors previously brought charges associated sharing http link leaked stratfor data charges dropped 2014 part sentence brown also required pay almost 900,000 stratfor prior 2011 brown ties hacktivist collective anonymous brown born dallas texas robert brown karen lancaster later divorced grew dallas exhibited early interest writing journalism creating newspapers family computer attending preston hollow elementary school went contribute school newspapers interned several weekly newspapers teenage years attended episcopal school dallas sophomore year high school spent would-be junior year tanzania father residing business africa brown completed high school online texas tech university program earning college credits well high school diploma 2000 enrolled university texas austin spent two semesters taking writing courses leaving school pursue full-time career freelance writer brown served director communications enlighten vote secularist pac provides financial strategic assistance political candidates advocate strict enforcement establishment clause 2010 brown began work crowdsourced investigation wiki project pm brown written main goals project pm increase positive influence calls capable segments blogosphere reducing negative influence well-regarded mainstream pundits may political agendas compatible public interest aim wiki project pm established way deliberate generation critical mass work following among dependable bloggers manner segments traditional media prompted even forced address critical issues methods means reportage experimental aim project pm also develop communicational schematic could provide bloggers reporters concerned citizen journalist best possible feed raw information produce content aim project pm brown stated institutions structures developed past two decades accelerating public internet use reasonably describe wholesome effect information flow information age work progress thus potential improvements made importantly improvements made initially small number influential participants working coordination purpose project pm implement solutions extent participants collectively able well demonstrate beneficial effects solutions others might spurred recreate even build upon independently efforts june 2011 project pm released exclusive report surveillance contract called romas/coin discovered e-mails hacked hbgary anonymous consisted sophisticated data-mining techniques leveraging mobile software aimed arab countries november 2011 brown said 75 names members zetas drug cartel would released member anonymous group kidnapped set free brown says member released truce drug cartel moment others said kidnapping fake january 18 2012 brown interviewed english language russian news network rt cyber attacks anonymous temporary blackout us government websites whitehouse.gov doj.gov fbi.gov march 6 2012 confirmed twitter fbi raided residence receiving information hector xavier monsegur also known online pseudonym sabu founder lulzsec early january 2014 announced second book begun 2006 published according legal defense website book originally titled hot fat clouded amazing amusing failures america ’ chattering class consisted attack ubiquitous newspaper columnists media pundits argues undeservedly influential able form public opinion … excited announce rescued book fate soon see light day newly titled keep rootin ’ putin establishment pundits twilight american competence text become available ebook spring 2014 donors legal defense fund september 2012 incarceration brown wrote series columns magazine titled barrett brown review arts letters jail 2015 transitioned intercept 2016 intercept national magazine award three barrett columns written daily beast vanity fair true/slant huffington post guardian publications media outlets presented brown spokesperson anonymous label disputes appeared documentaries legion terms conditions may apply hacker wars brown said renounced links group 2011 also reported 2011 brown anon alumnus gregg housh landed six-figure deal amazon book tentatively titled anonymous tales inside accidental cyberwar march 6 2012 fbi executed search warrants brown apartment mother house seeking evidence alleged crimes items seized included records relating hbgary infragard endgame systems anonymous lulzsec irc chats twitter wiki.echelon2.org pastebin.com agents took possession laptop computers suspect fbi working incorrect information brown told reporter september 12 2012 brown arrested dallas county texas threatening fbi agent youtube video arrest occurred left computer linked tinychat raid could heard background brown talked publicly history using heroin going withdrawal day arrest magistrate denied bail therefore kept pre-trial detention danger safety community risk flight september 24 2012 pastebin post appeared titled barrett brown – communiqué prison 9/20/12 brown thanked supporters described insufficient medical treatment received ribs injured arrest acknowledged past mistakes missive concludes personally thank everyone outside helped movement particularly critical time regained freedom nothing lose time war paper always war october 3 2012 federal grand jury indictment returned brown charges threats conspiracy retaliation federal law enforcement officer various tweets youtube uploads comments made brown arrest cited support within indictment later entered plea guilty three counts december 4 2012 brown indicted additional 12 federal charges related december 25 2011 hack austin-based private intelligence company stratfor carried jeremy hammond trove millions stratfor emails hack including authentication information thousands credit card accounts shared hacker collective lulzsec whistleblower site wikileaks main article 2012 stratfor email leak hammond pleaded guilty received maximum sentence ten years federal prison hack brown faced 45 years federal prison allegedly sharing link data part project pm presumed fbi entrapment maneuver attorney jesselyn radack raised connections brown case client peter van buren state department sought prosecute link personal blog wikileaks document two online commentators internet security issues criticized charges brown entered plea guilty twelve counts january 23 2013 third indictment filed brown two counts obstruction concealing evidence march 6 2012 fbi raid mother homes brief court hearing week later judge found mentally competent stand trial brown pleaded guilty additional charges may 1 2013 announced brown retained two attorneys charles swift ahmed ghappour represent legal cases september 4 2013 brown federal court-issued gag order lawyers allowed discuss case media lest taint jury assistant united states attorney candina s. heath lead prosecutor said brown tried manipulate media behind bars benefit brown attorney coordinates and/or approves use media publicity brown contained false information gross fabrications defense counsel maintained gag order unfounded unwarranted breach brown first amendment rights though forbidden write speak case brown continued pen articles prison cell unrelated topics gag order lifted april 23 2014 key documents unsealed brown custody since september 12 2012 mother sentenced november 8 2013 six months probation 1,000 fine misdemeanor charge obstructing execution search warrant better judgment clouded maternal instinct stated court judge said feel parent know best could march 2014 charges brown dropped april 2014 reported brown agreed plea bargain january 2015 brown sentenced 63 months prison also ordered pay 890,250 fines restitution journalist janus kopfstein said believed government considered brown threat suggested prosecutors made false allegations used increase length sentence supporting theory much brown december sentencing hearing spent drawn-out arguments definitions project pm brown brown released prison november 29 2016 moved halfway house five drug dealers close downtown dallas texas april 27 2017 brown arrested held unknown charges four days released gave interview democracy house arrest despite pressure government speak media brown expressed desire move iceland germany possible telling truthout interview ca n't stay us ca n't get work done 'm always subject little gusts bureaucracy wo n't another year 'm probation another two years generally goes one year n't act year 'll position leave 2017 lawyers donors brown legal fund filed suit assistant united states attorney candina heath filing subpoena wepay resulted divulgence identities lawyers argued irrelevance donor information case brown provision information directly special agent robert smith federal bureau investigation rather prosecutor judge trial led donors belief information intended surveil harass donors activity protected u.s. constitution filed destruction data monetary damages october 2 2017 judge maria elena james denied motion dismiss case introduced department justice sentencing statement brown alleged despite denial subpoena judge making statement identities contributors echelon2.org public wiki obtained means dozens people given time expertise hailed journalists advocacy groups crucial journalistic enterprise risk indicted sort spurious charges facing long ago government exposed decades prison time copying pasting link publicly available file journalists also linking without prosecuted relatively free documentary film released 2016 field vision brown drive across texas halfway house released prison barrett brown case included plot point season 2 u.s. tv series house cards brown serves advisory board international modern media institute
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Computer security
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maliit maliit input method framework computers particular focus implementing virtual keyboards designed mostly touchscreen devices maliit allows inputting text without presence physical keyboard advanced features word correction prediction also available originating part meego maliit free software licensed lgpl maliit deployed standard component nokia n9 kde plasma active luneos olpc devices ubuntu touch maliit originally developed part meego nokia eventually shipped part meego handset “ day 1 ” software platform meego project ended maliit transferred independent project free software consulting firm openismus first formally independent release 0.80.0 maliit 0.99 released switched qt 4 qt 5 among maliit ’ features plugin-based architecture word correction prediction multitouch context sensitive layouts running linux kernel handling input hardware relies evdev maliit adopted x11 well wayland
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Operating systems
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grapple network layer grapple free software package adding multiplayer support computer games applications uses internet protocols supporting tcp/ip udp/ip intended simple enough multiplayer features added game little dozen lines code also offers advanced features desired grapple takes care creating monitoring closing connections server supports multiple servers message-oriented system clients servers message queue also relay messages client client also provides fully functional lobby system package created 2006 michael simms linux game publishing released gnu lgpl features grapple supports time
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Operating systems
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ifund ifund us 200 million capital fund developers may enter equity deals creation applications services components apple inc. iphone ipod touch ipad platform offered managed venture capital company kleiner perkins caufield byers kpcb ifund announced kpcb partner john doerr time iphone os sdk apple iphone roadmap event march 6 2008 cupertino california ifund managed kpcb partner matt murphy collaboration partners chi-hua chien john doerr bill joy randy komisar ellen pao ted schlein apple provides kpcb market insight support march 31 2010 kpcb announced fund doubled september 15 2008 kpcb launched blog share perspectives ifund december 2008 confidential ifund application data accidentally published web kleiner perkins caufield byers ’ former hosting provider meteora technologies group database dump file file indexed google coincidentally discovered fruux staffer file contained applications 588 companies including detailed information companies like founder bios financial ratios business models
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Operating systems
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file system fragmentation computing file system fragmentation sometimes called file system aging tendency file system lay contents files non-continuously allow in-place modification contents special case data fragmentation file system fragmentation increases disk head movement seek time applies known hinder throughput addition file systems sustain unlimited fragmentation correction existing fragmentation reorganize files free space back contiguous areas process called defragmentation modern computers ssd disks rotate really discs conventional sense file system fragmentation n't much performance problem fixed movement heads discs fact overly defragmenting drives slowly shorten life-span file system first initialized partition contains small internal structures otherwise one contiguous block empty space means file system able place newly created files anywhere partition time creation files laid near-optimally operating system applications installed archives unpacked separate files end occurring sequentially related files positioned close existing files deleted truncated new regions free space created existing files appended often impossible resume write exactly file used end another file may already allocated thus new fragment allocated time goes factors continuously present free space well frequently appended files tend fragment shorter regions free space also mean file system longer able allocate new files contiguously break fragments especially true file system becomes full large contiguous regions free space unavailable following example simplification otherwise complicated subject consider following scenario new disk five files named b c e saved continuously sequentially order file using 10 blocks space block size unimportant remainder disk space one free block thus additional files created saved file e. file b deleted second region ten blocks free space created disk becomes fragmented empty space simply left marked available later use used needed file system could defragment disk immediately deletion would incur severe performance penalty unpredictable times new file called f requires seven blocks space placed first seven blocks newly freed space formerly holding file b three blocks following remain available another new file called g needs three blocks added could occupy space f c. subsequently f needs expanded since space immediately following occupied three options file system second option probably impractical performance reasons third file large third option impossible single contiguous free space large enough hold new file thus usual practice simply create extent somewhere else chain new extent onto old one material added end file f would part extent much material room available last extent another extent would created eventually file system free segments many places files may spread many extents access time files files may become excessively long early file systems unable fragment files one example acorn dfs file system used bbc micro due inability fragment files error message ca n't extend would times appear user would often unable save file even disk adequate space dfs used simple disk structure files disk located length starting sector meant files exist continuous block sectors fragmentation possible using example table attempt expand file f step five would failed system ca n't extend error message regardless much free space might remain disk total available extend data file standards error handling time primitive case programs squeezed limited memory bbc micro could rarely afford waste space attempting handle errors gracefully instead user would find dumped back command prompt ca n't extend message data yet appended file would lost problem could solved simply checking free space disk beforehand either free space disk may exist size largest contiguous block free space immediately apparent without analyzing numbers presented disk catalog would escape user notice addition almost dfs users previously used cassette file storage suffer error upgrade floppy disk system expensive upgrade shock upgrade might without warning cause data loss file system fragmentation may occur several levels individual file fragmentation occurs single file broken multiple pieces called extents extent-based file systems disk file systems attempt keep individual files contiguous often possible without significant performance penalties file system check defragmentation tools typically account file fragmentation fragmentation percentage statistic free unallocated space fragmentation occurs several unused areas file system new files metadata written unwanted free space fragmentation generally caused deletion truncation files file systems may also intentionally insert fragments bubbles free space order facilitate extending nearby files see preventing fragmentation file segmentation also called related-file fragmentation application-level file fragmentation refers lack locality reference within storing medium related files see file sequence detail unlike previous two types fragmentation file scattering much vague concept heavily depends access pattern specific applications also makes objectively measuring estimating difficult however arguably critical type fragmentation studies found frequently accessed files tend small compared available disk throughput per second avoid related file fragmentation improve locality reference case called file contiguity assumptions active observations operation applications made frequent assumption made worthwhile keep smaller files within single directory together lay natural file system order often reasonable assumption always hold example application might read several different files perhaps different directories exactly order written thus file system simply orders writes successively might work faster given application file system fragmentation problematic consumer-grade hard disk drives increasing disparity sequential access speed rotational latency lesser extent seek time file systems usually placed thus fragmentation important problem file system research design containment fragmentation depends on-disk format file system also heavily implementation file system fragmentation less performance impact upon solid-state drives mechanical seek time involved however file system needs store one additional piece metadata corresponding file piece metadata occupies space requires processing power processor time maximum fragmentation limit reached write requests fail simple file system benchmarks fragmentation factor often omitted realistic aging fragmentation difficult model rather simplicity comparison file system benchmarks often run empty file systems thus results may vary heavily real-life access patterns several techniques developed fight fragmentation usually classified two categories preemptive retroactive due difficulty predicting access patterns techniques often heuristic nature may degrade performance unexpected workloads preemptive techniques attempt keep fragmentation minimum time data written disk simplest appending data existing fragment place possible instead allocating new blocks new fragment many today file systems attempt preallocate longer chunks chunks different free space fragments called extents files actively appended largely avoids file fragmentation several files concurrently appended thus avoiding becoming excessively intertwined final size file subject modification known storage entire file may preallocated example microsoft windows swap file page file resized dynamically normal operation therefore become highly fragmented prevented specifying page file minimum maximum sizes effectively preallocating entire file bittorrent peer-to-peer filesharing applications limit fragmentation preallocating full space needed file initiating downloads relatively recent technique delayed allocation xfs hfs+ zfs technique also called allocate-on-flush reiser4 ext4 file system written file system blocks reserved locations specific files laid yet later file system forced flush changes result memory pressure transaction commit allocator much better knowledge files characteristics file systems approach try flush files single directory contiguously assuming multiple reads single directory common locality reference improved reiser4 also orders layout files according directory hash table files accessed natural file system order dictated readdir always read sequentially retroactive techniques attempt reduce fragmentation negative effects fragmentation occurred many file systems provide defragmentation tools attempt reorder fragments files sometimes also decrease scattering i.e improve contiguity locality reference keeping either smaller files directories directory trees even file sequences close disk hfs plus file system transparently defragments files less 20 mib size broken 8 fragments file opened obsolete commodore amiga smart file system sfs defragmented filesystem use defragmentation process almost completely stateless apart location working stopped started instantly defragmentation data integrity ensured metadata normal data
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Computer file systems
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enhanced entity–relationship model enhanced entity–relationship eer model extended entity–relationship model computer science high-level conceptual data model incorporating extensions original entity–relationship er model used design databases developed reflect precisely properties constraints found complex databases engineering design manufacturing cad/cam telecommunications complex software systems geographic information systems gis eer model includes concepts introduced er model additionally includes concepts subclass superclass is-a along concepts specialization generalization furthermore introduces concept union type category used represent collection objects union objects different entity types eer model also includes eer diagrams conceptual models accurately represent requirements complex databases entity type subtype subclass entity type x every necessarily x subclass entity inherits attributes relationships superclass entity property called attribute relationship inheritance subclass entity may specific attributes relationships together attributes relationships inherits superclass common superclass example vehicle superclass along subclasses car truck number common attributes car truck would part superclass attributes specific car truck max payload truck type ... would make two subclasses textbooks discussing eer implementation using purely relational databases booklet discussing eer implementation using object-oriented object-relational databases textbook discussing implementation relational object-relational databases shorter survey articles
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Databases
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wandisco wandisco plc. dually headquartered sheffield england san ramon california us public software company specialized area distributed computing development offices san ramon california sheffield england belfast northern ireland wandisco corporate contributor hadoop subversion open source projects name wandisco acronym wide area network distributed computing initially offering replication solution distributed teams using concurrent versions system cvs expanded include apache subversion svn multisite plus 2006 git git multisite 2013 gerrit gerrit multisite 2014 2012 wandisco acquired altostor entered big data market non-stop hadoop product altostor founders dr. konstantin shvachko jagane sundar joined wandisco part acquisition helped develop company next generation hadoop product released 2015 wandisco fusion wandisco distributed coordination engine dcone shared component wandisco clustering products dcone system allows multiple instances application operate independent hardware without sharing resources application servers kept synchronisation dcone regardless whether servers lan globally separated accessible wide area network wan wandisco replication technology work yeturu aahlad previously worked sun netscape ibm involved developing corba framework aahlad theorized model effective active replication wan development dcone wandisco taken paxos algorithm baseline added innovations relevant mission-critical high transaction volume distributed environments wandisco provides replication products cvs apache subversion git gerrit apache hadoop amazon web services microsoft azure google cloud platform addition company offers support consultancy training services company website lists companies arm avaya bally technologies barclays blackrock bosch cisco dell emc disney fujitsu general electric honda juniper networks pitney bowes april 2016 wandisco announced ibm signed deal oem wandisco fusion deal allows ibm rebrand fusion ibm big replicate plays important role ibm big data cloud computing strategy including movement data on-premises software cloud july 2018 wandisco announced filed new patent blockchain company claims patent enables effective permissioned blockchain transactions underlying algorithmic mechanism mechanism enables throughput achieved orders magnitude higher public blockchains 2011 wandisco announced ubersvn deployment apache subversion included web based management console ability add additional application lifecycle management features ubersvn download available mid-2013 september 2013 wandisco announced official sponsor uc berkeley amplab five-year collaborative effort university california berkeley wandisco one apache hadoop committer staff jagane sundar february 2013 wandisco released free distribution hadoop containing additional components developed wandisco wandisco involved apache subversion open source project 2008 2015 employed several contributors work subversion project time wandisco provides subversion binary downloads windows centos debian oracle linux rhel suse linux ubuntu mac os x solaris via website binaries use default package management system linux distribution december 2010 wandisco announced intention develop features subversion project specifically aimed improving branching merging functionality apache foundation subversion developers said announcement contained unfounded claims insinuations community involvement lack development features according apache features already worked time david richards wandisco clarified position subversion community followed announcing wandisco sponsorship ongoing support work apache software foundation
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Distributed computing architecture
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hacktivity hacktivity conference traditional event budapest hungary official alternative representatives information security profession meet interested field framework time informal informative sometimes in-depth technological participants official alternative experts information security profession universities colleges professors participating training young people participating high level education/university college students professional trade unions
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Computer security
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visual programming language computing visual programming language vpl programming language lets users create programs manipulating program elements graphically rather specifying textually vpl allows programming visual expressions spatial arrangements text graphic symbols used either elements syntax secondary notation example many vpls known dataflow diagrammatic programming based idea boxes arrows boxes screen objects treated entities connected arrows lines arcs represent relations vpls may classified according type extent visual expression used icon-based languages form-based languages diagram languages visual programming environments provide graphical iconic elements manipulated users interactive way according specific spatial grammar program construction general goal vpls make programming accessible novices support programmers three different levels visually transformed language non-visual language superimposed visual representation naturally visual languages inherent visual expression obvious textual equivalent current developments try integrate visual programming approach dataflow programming languages either immediate access program state resulting online debugging automatic program generation documentation dataflow languages also allow automatic parallelization likely become one greatest programming challenges future visual basic visual c visual j etc languages microsoft visual studio ide visual programming languages representation algorithms etc textual even though ide embellishes editing debugging activities rich user interface similar consideration applies rapid application development environments typically support form designer sometimes also graphical tools illustrate define control flow data dependencies parsers visual programming languages implemented using graph grammars following contains list notable visual programming languages many modern video games make use behavior trees principle family simple programming languages designed model behaviors non-player characters behaviors modeled trees often edited graphical editors article originally based material free on-line dictionary computing used update needed
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Programming language topics
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corel linux corel linux also called corel linuxos debian-based operating system made corel began beta testing september 21 1999 released public november 15 1999 mainly competed windows 98 windows 2000 microsoft plus mac os 9 apple corel later discontinued distribution remove former corel open source development website march 2002 corel use kfm standard kde file manager instead used file manager cfm along modifications corel made made operating system incompatible versions linux much competitors industry time relatively little linux software available serious hurdle corel users operating system second edition released august 15 2000 download regular deluxe editions latter bundled corel wordperfect office linux xandros purchased corel linux source code development team corel scrapped linux business august 2001 however corel corporation stockholder xandros corel linux following system requirements corel linux featured file manager close look feel windows explorer file manager provided integrated windows smb network browser company also advertised operating system compatible flagship software key selling point corel linux compatibility company wordperfect applications eponymous word processor eighth version given away personal customers hopes would purchase wordperfect office 2000 suite added quattro pro corel presentations corelcentral programs deluxe version suite added paradox database manager latter omits level editor network mode scenarios original game 'limited edition corel linux deluxe came instead railroad tycoon ii unlike free wordperfect 8 office suite written natively linux instead consisted windows programs powered corel fork wine compatibility layer result linux suite suffered performance penalty compared windows version wordperfect 8 wordperfect suite corel adapted graphics applications run linux using wine consisted coreldraw stylized coreldraw suite eponymous program paid software corel photo-paint available free download corel smartmove part corel linux application provided following smartmove built around wine libraries read windows registry settings windows applications thus able migrate smartmove core libraries created wrapper windows registry easily look settings smartmove looks existing microsoft windows installations machine looks little individual users offers transfer application settings analogous programs linux understands deal internet explorer netscape cookies bookmarks outlook mirc icq settings variety desktop preferences including wallpaper color scheme even mouse handedness tried settings since windows installation fairly new n't much check death corel linux application faded away longer maintained however similar functionality available least ubuntu installing dual-boot configuration machine already windows
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Operating systems
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mondo rescue mondo rescue free disaster recovery software supports linux i386 x86-64 ia-64 freebsd i386 packaged multiple distributions red hat rhel fedora centos opensuse sles mandriva debian ubuntu gentoo also supports tapes disks usb devices network cd/dvd backup media multiple filesystems lvm software hardware raid restoration may done physical media including obdr tape support cd/dvd/usb media network pxe mentioned free software directory emphasis stability ease use according ohloh mondorescue development worth 6m mondo uses linux distribution called mindi provide favorable post boot environment performing data restore unlike disk clone solutions ready use live cd provided mondo rescue instead included mindi package create custom turn-key live cd/dvds using exact linux kernel configuration system backed effect bootable dvd/cd customized computer backed objective reduce possibility missing device drivers kernel incompatibilities may arise using generic vanilla linux kernel pre-built live dvd/cd
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Computer security
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cloudlocker cloudlocker personal cloud device created stoamigo based paradise nevada cloudlocker offers cloud storage data conversion file sharing powered stoamigo platform unlike public cloud service involves third party access users ’ digital media cloudlocker on-premises cloud solution stays user ’ possession connects home office network via plug play interface cloud computing storage widely acknowledged next big thing many people wary privacy concerns uncomfortable storing personal data pictures videos somebody else ’ server core challenge data privacy share data protecting personal information public cloud storage services google amazon microsoft dropbox offer level protection personal information would available information kept home office according report world privacy forum report found “ information stored business individual third party may fewer weaker privacy protections information possession creator information. ” report goes state “ government agencies private litigants may able obtain information third party easily creator information. ” cloudlocker one many different personal cloud options market today cloudlocker falls server device cloud category personal cloud solutions cloudlocker attempts address internet privacy issue providing personal cloud server users keep sole possession gives global access remote browser user ’ internet-enabled devices files stored cloudlocker accessed pc laptop smartphone tablet via stoamigo platform stoamigo account stoamigo desktop web mobile applications designed sharing viewing streaming digital media cloudlocker used file sharing anyone even stoamigo account users decide share digital media user set permissions recipients view-only download share private file files shared anyone else users share files folders lists multiple contacts customize permission settings person user arrange receive notifications viewed downloaded shared files thus establish audit trail access specific files folders users may modify settings shared files time share choose retract shared files everyone selected recipients users create listen playlists watch video files continuous play devices streaming cloudlocker downloading required native media player streams files cloudlocker dlna compatible user able view media content cloudlocker dlna tv dlna device cloudlocker comes usb ports user attach external hard drives cloudlocker use space additional storage thereby making storage space limitless stoamigo android ios app option create qr code mobile device share file folder list files music playlist cloudlocker stoamigo also available europe
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Distributed computing architecture
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caldav calendaring extensions webdav caldav internet standard allowing client access scheduling information remote server extends webdav http-based protocol data manipulation specification uses icalendar format data access protocol defined allows multiple client access information thus allowing cooperative planning information sharing many server client applications support protocol extensions caldav automated scheduling also standardized caldav specification first published 2003 internet draft submitted internet engineering task force ietf lisa dusseault march 2007 caldav specification finished published ietf rfc 4791 authored cyrus daboo apple bernard desruissaux oracle lisa dusseault commercenet caldav designed implementation collaborative software client server needs maintain access share collections events developed open standard foster interoperability software different implementers architecture caldav partially inherited underlying specifications organizes data events tasks free-busy info notes directories collections multiple items resources reside resources collections accessed one users using standard http dav semantics detect conflicting changes provide locking access control concept acls used operation view edit delete etc denied granted per user therefore specification requires caldav servers must support webdav access control protocol rfc 3744 calendar resources must use icalendar format allows server understand process data parsing icalendar items necessary server support number calendaring-specific operations free-busy time reports expansion recurring events functionality user may synchronize calendar caldav server share among multiple devices users protocol also supports non-personal calendars calendars sites organizations list caldav clients includes list caldav server includes
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Internet protocols
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salesforceiq salesforceiq formerly relateiq subsidiary salesforce.com american software company based palo alto california company software involves relationship intelligence platform combines data email systems smartphone calls appointments augment replace standard relationship management tools database solutions scans 10,000 emails calendar entries data points per minute first run july 2014 salesforce.com announced plans acquire company close 400 million company founded july 2011 adam evans steve loughlin end july 2013 company hired data scientist dj patil vp product leadership team also includes vp sales armando mann recent head sales dropbox former google executive vp marketing elise bergeron formerly facebook unlike traditional relationship management systems rely data input users keep teams informed run predictive analytics salesforceiq platform automatically isolates analyzes user professional emails interactions combining data information gleaned sources linkedin facebook salesforceiq leverages data science comb emails analyze offer reminders suggestions busy salespeople march 2014 company released closest connections feature automates normally time-consuming—and potentially erroneous—sales process identifying warm introductions potential prospects based real activity happening within team email inboxes phones calendars social networks part 2015 dreamforce conference relateiq rebranded salesforceiq
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Distributed computing architecture
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m.u.l.e m.u.l.e seminal multiplayer video game originally written atari 8-bit family ozark softscape published 1983 electronic arts designed danielle bunten berry m.u.l.e ported commodore 64 nintendo entertainment system ibm pcjr japanese versions also exist pc-8801 sharp x1 msx 2 computers plays like strategy game incorporates aspects simulate economics set fictional planet irata atari backwards game exercise supply demand economics involving competition among four players computer opponents automatically filling missing players players provided several different choices race colonist providing different advantages disadvantages paired respective strategies win players compete amass largest amount wealth must also cooperate survival colony central game acquisition use m.u.l.e multiple use labor element develop harvest resources player real estate depending outfitted m.u.l.e configured harvest energy food smithore m.u.l.e.s constructed crystite valuable mineral available tournament level players must balance supply demand elements buying need selling n't players may also exploit create shortages refusing sell players store raises price resource following turns scheming players encouraged allowing collusion initiates mode allowing private transaction crystite one commodity influenced supply demand considerations deemed sold 'off world strategy resource somewhat different—a player may attempt maximize production without fear much supply demand resource required certain things turn instance player short food less time take one turn similarly player short energy land plots wo n't produce output shortage smithore raise price m.u.l.e.s store prevent store manufacturing new m.u.l.e.s make use one land players must also deal periodic random events run-away m.u.l.e.s sunspot activity theft space pirates meteorite potentially destructive beneficial effects game features balancing system random events impact single player favorable events never happen player currently first place unfavorable events never happen player last place leveling playfield applied whenever tie happens game e.g two players want buy resource price player losing position automatically wins tie players also hunt mountain wampus cash reward according jim rushing one four original partners ozark softscape m.u.l.e initially called planet pioneers development intended similar cartels cutthroats graphics better playability focus multiplayer real-time auction element came largely lead designer danielle bunten wheeler dealers board game monopoly used model game encouragement social interaction monopoly came several game elements acquisition development land primary task economy scale effect wherein grouped plots multiple plots type would increased production quantities also inspired different species different tokens monopoly random events affecting individual similar chance cards additional game features claim jumping loans crystite depletion discarded adding complexity without enhancing gameplay setting inspired robert a. heinlein time enough love wherein galactic colonization style american old west pioneers drive primitive tools m.u.l.e based idea genetically modified animal heinlein novel given appearance star wars imperial walker another heinlein novel moon harsh mistress provided decision government external authority land originally sold auction caused feedback loop wealthiest player land thus made money thus developers created land authority gives player free plot land turn ozark softscape developed game atari 8-bit first policy developing advanced computers porting platforms removing altering features sprites necessary bunten stated ozark port game apple ii series m.u.l.e ca n't done apple pc port m.u.l.e developed k-byte software affiliate electronic arts published ibm part venture home market pcjr sold poorly due released 1985 latter discontinued although game actual pcjr support copies existed internet considered lost 2012 vince bray found original disk archived jeff leyda jim leonard m.u.l.e sold 30,000 copies lauded reviewers computer gaming world described fascinating enjoyable game comes best point four human players minor criticisms included too-weak computer opponents lack save feature softline called m.u.l.e computer games like game learning experience also stimulating fun frustrating thought provoking fun addictive fun magazine praised offering valuable lessons economic topics noting learned hard way concluded game feels good virtually flawless human-computer human-human competition john j. anderson wrote creative computing also mention shooting found anywhere game positively refreshing ... mule belongs every atari software shelf world every home every school near every atari scott mace infoworld called m.u.l.e unusual ease allows multiplayer interaction single game computer console wrote would incredible lasting power like best board games stated learned economics marketplace m.u.l.e ever college leo laporte hi-res also said learned economics game college predicted m.u.l.e may revitalize video game industry ought make rich anyway praised theme captivating musical come-on 've ever heard concluded ask m.u.l.e perfect game reporting byte children loved jerry pournelle described m.u.l.e cross hammurabi diplomacy arcade game lots strategic decisions—provided 're skillful enough joystick implement 've decided another reviewer wrote magazine impossible adequately describe interaction economically realistic subtleties m.u.l.e concluding intriguing way illustrate triumphs perils free enterprise orson scott card compute 1983 gave m.u.l.e two ea games worms complimentary reviews writing original set well allow player take part creativity things computers magazine listed game may 1988 one favorite games stating requires sense strategy well proficiency joystick maneuvers steven list reviewed m.u.l.e space gamer 70 commented m.u.l.e simply great game tour de force programming design good family entertainment educational exciting n't computer disk drive may worth investment able play addison-wesley book atari software 1984 gave game overall rating stating combines best features monopoly economic simulation games like hammurabi teaching valuable lessons economies fun way book noted several people play game becomes involved interactive two zzap 64 reviewers stated 1985 m.u.l.e excellent trading game recommended novice skilled third complained found little excitement ... nothing keep interested 1984 m.u.l.e awarded 1984 best multi-player video game/computer game 5th annual arkie awards judges described unique blend boardgame strategy computer-game pacing noted since release 'm.u.l.e gained intense cult following softline readers named game third most-popular atari program 1983 score 7.44 10 1988 m.u.l.e among first members computer gaming world hall fame honoring games rated highly time readers 1992 1994 surveys science fiction games magazine gave title five five stars calling all-time computer classic one games ever devised playable entertaining four humans economics made fun ... still holds well years provides justification holding onto 8-bit atari 1996 magazine named m.u.l.e 3 best games time list named 5 ten greatest pc games ever pc world 2009 m.u.l.e listed 19th important video game time 1up.com chris crawford said game considering platform team deal m.u.l.e greatest game design ever done computer gaming world reported april 1994 ea working videogame version game design terminated creative differences publisher designer magazine reported rumor may 1994 sega genesis version completed ea debating release reported august 1994 bunten decided remaking game ea wanted put guns bombs editorial asked company give us m.u.l.e smithore crystite creator intended bunten working internet version m.u.l.e death 1998 2005 netplay component called kaillera integrated atari800winplus emulator enabling original game played internet several m.u.l.e clones exist including subtrade traders space horse online remake game called planet m.u.l.e released december 6 2009 game free download major platforms comma 8 studios later acquired mobile m.u.l.e license released m.u.l.e returns ios november 2013 super mario bros creator shigeru miyamoto cited m.u.l.e influence pikmin series wright dedicated game sims memory bunten m.u.l.e theme song included wright later game spore easter egg space level ability allows terran players call multiple robotic workers called m.u.l.e.s board game adaptation m.u.l.e board game released 2015 according twin galaxies following records recognized
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Computer architecture
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memwatch memwatch free programming tool memory leak detection c released gnu general public license designed compile run system ansi c compiler primarily intended detect diagnose memory leaks also used analyze program memory usage provided logging facilities memwatch differs debugging software compiled directly program debugged instead compiled separately loaded program runtime
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Operating systems
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unikey unikey technologies alternative access control company based united states designs licenses keyless entry technology worldwide first product partnership kwikset kēvo bluetooth-enabled deadbolt door lock unikey technologies founded 2010 florida phil dumas serves president chief executive officer electrical engineering degree university central florida background biometric security dumas part team launched smartscan first mass-market biometric residential deadbolt lock started unikey effort create dependable convenient way access everything unikey technologies first came public attention may 2012 dumas appeared abc reality series shark tank unikey received investment offers five judges show including offer 500,000 40 equity stake mark cuban kevin o'leary dumas accepted offer ultimately unable come terms show 2013 unikey raised approximately 2.6 million funding led ff venture capital year unikey announced licensing deal kwikset largest residential lock manufacturer united states one largest world manufacture distribute kēvo residential smart lock using unikey technology launched 2013 kēvo first bluetooth-enabled touch-to-open smart lock kēvo ability detect user compatible smartphone tablet via app lock unlock door deadbolt lock senses user phone nearby outside phone emits low-energy bluetooth signal allowing door unlocked lock face touched making unnecessary interact phone order open door users grant unrestricted temporary access phones well kēvo also comes keychain fob provides touch-to-open function authorized smart phone prime security feature product unikey inside/outside intelligence detects whether verified device currently inside outside home authorized device known inside house unauthorized users unable activate kēvo outside system acts one-way filter lets authorized users pass entryway june 2014 unikey miwa lock company announced partnership offer keyless entry hotels unikey developed touch-to-open passive keyless entry system integrated miwa existing radio-frequency identification hospitality locks keys activated smartphone apps guests check app sent room number phone enabled act virtual key following miwa partnership unikey making way commercial access control industry partnerships grosvenor technologies nortek security control company also expanded international reach partnership uk home security company era
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Computer security
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libata libata library used inside linux kernel support ata host controllers devices libata provides ata driver api class transports ata atapi devices scsi ata translation ata devices according t10 sat specification features include power management s.m.a.r.t. pata/sata atapi port multiplier hot swapping ncq
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Computer architecture
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connection-oriented communication connection-oriented communication network communication mode telecommunications computer networking communication session semi-permanent connection established useful data transferred stream data delivered order sent alternative connection-oriented transmission connectionless communication example datagram mode communication used ip udp protocols data may delivered order since different network packets routed independently may delivered different paths connection-oriented communication may circuit switched connection packet-mode virtual circuit connection latter case may use either transport layer virtual circuit protocol tcp protocol allowing data delivered order although lower layer switching connectionless may data link layer network layer switching mode data packets belonging traffic stream delivered path traffic flows identified connection identifier rather complete routing information allowing fast hardware based switching connection-oriented protocol services often always reliable network services provide acknowledgment successful delivery automatic repeat request functions case missing data detected bit-errors atm frame relay mpls examples connection-oriented unreliable protocol circuit switched communication example public switched telephone network isdn sonet/sdh optical mesh networks intrinsically connection-oriented communications systems circuit mode communication provides guarantees data arrive constant bandwidth constant delay in-order delivery bit stream byte stream provided switches reconfigured circuit establishment phase packet switched communication may also connection-oriented called virtual circuit mode communication due packet switching communication may suffer variable bit rate delay due varying traffic load packet queue lengths connection-oriented communication necessarily reliable protocols keep track conversation connection-oriented protocols sometimes described stateful connection-oriented transport layer protocols provide connection-oriented communications connectionless communications systems connection-oriented transport layer protocol tcp may based connectionless network layer protocol ip still achieves in-order delivery byte-stream means segment sequence numbering sender side packet buffering data packet reordering receiver side sequence numbering requires two-way synchronization segment counters three-step connection establishment phase connection-oriented packet switched data link layer network layer protocol data sent path communication session protocol identifies traffic flows channel/data stream number often denoted virtual circuit identifier vci rather complete routing information packet source destination addresses used connectionless datagram switching conventional ip routers connection-oriented communication routing information may provided network nodes connection establishment phase vci defined tables node thus actual packet switching data transfer taken care fast hardware opposed slow software based routing typically connection identifier small integer 10 bits frame relay 24 bits atm example makes network switches substantially faster routing tables simple look-up tables trivial implement hardware impact great fact even characteristically connectionless protocols ip traffic tagged connection-oriented header prefixes e.g. mpls ipv6 built-in flow id field atm frame relay example examples connection-oriented unreliable data link layer protocols also reliable connectionless protocols well ax.25 network layer protocol passes data i-frames combination rare reliable-connectionless uncommon modern networks connection-oriented protocols handle real-time traffic substantially efficiently connectionless protocols especially short constant length packets atm yet replaced ethernet carrying real-time isochronous traffic streams especially heavily aggregated networks like backbones motto bandwidth cheap fails deliver promise experience also shown over-provisioning bandwidth resolve quality service issues hence 10- gigabit ethernet expected replace atm time connection-oriented protocols designed altered accommodate connection-oriented connectionless data examples connection-oriented packet mode communication i.e virtual circuit mode communication
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Internet protocols
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ubuntu hacks ubuntu hacks tips tools exploring using tuning linux book tips ubuntu popular linux distribution book published o'reilly media june 2006 part o'reilly hacks series
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Operating systems
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treering treering silicon valley ca-based technology company providing on-demand digital printing customizable school yearbooks us canada one first start-ups changed traditional yearbook industry company designed free software social-networking features allowing creation personalized yearbooks offered new business model eliminating financial cost yearbooks schools treering publishing platform allows high school community collaborate web-based yearbooks saved using cloud storage users add share comment photos memories events students parents customize copy school yearbook uploading content personalized pages result addition print version schools opt share online yearbook company business model impose financial obligation schools signing treering unlike traditional publishers business models based offset printing techniques minimum orders ordering paying yearbooks done online 2012 treering printed 125,000 yearbooks raised 3.6 million first round venture funding silicon valley list company investors included mike mccue flipboard co-founder rich barton expedia zillow founder second avenue partners cedar grove investments others 2013 company served 2,000 schools across us anticipating production 200,000 yearbooks company prints yearbooks recycled paper plants tree every printed copy
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Web technology
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phoenix-rtos phoenix-rtos real-time operating system designed internet things appliances main goal system facilitate creation software defined solutions phoenix-rtos successor phoenix operating system developed 1999-2001 pawel pisarczyk department electronics information technology warsaw university technology phoenix originally implemented ia-32 microprocessors adapted arm7tdmi processor 2003 powerpc 2004 system available gpl license decision abandon development phoenix write phoenix-rtos scratch taken creator 2004 2010 phoenix systems company established aiming commercialize system phoenix-rtos 2.0 based monolithic kernel initially versions ia-32 processor configurable esi-risc developed cooperation nxp semiconductors phoenix-rtos 2.0 also adapted vybrid arm cortex-a5 platform version equipped prime phoenix-prime g3-plc phoenix-g3 protocol support used smart grid networks phoenix-rtos runs applications designed written unix operating system phoenix-rtos version 3.0 based microkernel expected completed 2017 geared towards measuring devices low power consumption main problem first implementation low kernel modularity difficulties management process software development device drivers file system drivers phoenix-rtos equipped haas hardware software modules allow implementation rich devices functionality e.g modems existing haas modules include 2016 energa-operator based poland installed 6.6k data concentrator units balancing meter functionality network based phoenix-rtos license agreements use system mass production smart meters signed
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Operating systems
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appshield appshield world first application firewall appshield conceptualized eran reshef gili raanan introduced market perfecto technologies sanctum summer 1999 appshield product first product inspect incoming hypertext transfer protocol requests block malicious attacks based dynamic policy composed analyzing outgoing html pages product faced many market adoption challenges sanctum forced introduce complementary solution named appscan demonstrate need application security 2004 f5 networks acquired appshield intellectual properties sanctum discontinued technology gartner ’ magic quadrant mq 2015 web application firewalls estimates global waf market size big 420 million 24 percent annual growth
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Computer security
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vesa display power management signaling vesa display power management signaling dpms standard vesa consortium power management video monitors example usage includes turning putting monitor standby period idle time save power commercial displays also incorporate technology vesa issued dpms 1.0 1993 basing work united states environmental protection agency epa earlier energy star power management specifications subsequent revisions included future vesa bios extensions standard defines signal h-sync v-sync pins standard svga monitor trigger monitor power saving capabilities dpms defines four modes normal standby suspended state power may still drawn order power indicator lights standard
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Computer architecture
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samsung wave ii s8530 samsung wave ii s8530 samsung wave ii successor samsung wave s8500 smartphone running bada 1.2 operating system designed samsung commercially released october 2010 wave slim touchscreen phone powered samsung hummingbird cpu s5pc110 includes 1 ghz arm cortex-8 cpu powerful built-in powervr sgx 540 graphics engine super lcd screen 720p high-definition video capture capabilities shortage super amoled screens one primary reasons release model design phone made mostly metal alloy measured 10.9 mm thick terms form factor slate style featuring 3 physical buttons front call reject/ shutdown main menu button screen screen capacitive touchscreen super lcd anti-smudge oleophobic coating top scratch-resistant tempered-glass gorilla glass display touch panel shown capable resisting extreme friction scratch-resistant screen resolution 800x480 wvga processor phone features 1 ghz soc internally contains arm cortex a8 cpu core identical arm cortex cpu core used apple a4 package package soc phone graphics engine sgx 540 said capable generating 90 million triangles per second soc used samsung galaxy 256mb+128mb ram hardware samsung wave s8500 camera phone features 5 megapixel supports 2592 x 1944 pixels along autofocus led flash geo-tagging face blink detection image stabilization touch focus etc features various shooting modes beauty shot smile shot continuous panorama vintage shot camcorder able shoot 720p hd recording 1280x720 30 fps flash well also able record slow motion video 320x240 120 fps flash features feature includes a-gps 2 gb/8 gb internal storage microsdhc slot additional 32 gb also magnetometer proximity sensor accelerometer 5.1-channel surround sound mobile theater music recognition fake call service smart search social hub first phone support bluetooth version 3.0 addition bluetooth 3.0 phone also features wi-fi 802.11 b/g/n hsdpa 3.2 mbit/s hsupa 2 mbit/s phone available european/asia 3g bandings north american 3g bandings keep mind north american 3g bandings version phone limited availability available us user interface phone one smartphone feature samsung bada operating system platform ui samsung touchwiz 3.0 touchwiz 3.0 like 2 predecessors touchwiz 2.0 touchwiz utilises widgets 3 notable widgets pre-installed touchwiz 3.0 daily briefing includes essential information weather finance ap mobile news schedule feeds updates buddies allows users call send texts read facebook/twitter feeds favourite contacts users allowed 10 homescreens add widgets applications terms internet browser samsung wave pre-installed dolphin browser v2.0 based webkit browser supports flash disabled default improve page load time default phone comes picsel viewer capable reading .pdf microsoft office file formats users selected countries buy download picsel office editor samsung apps samsung apps users also download applications games widgets application store software includes gps software comes phone lbs route 66 palringo im facebook twitter social hub mini diary daily briefing memo video player fm radio media browser voice recorder e-mail pre-installed asphalt5 media support mp3 aac aac+ e-aac+ wma amr wav mp4 flac mpeg4 h.263 h.264 wmv avi divx xvid mkv android porting due many owners phone disliking bada software many people worked porting popular android o.s wave 2 ported versions known froyo gingerbread ice cream sandwich jelly bean kitkat however still developed features gps may limited function intended samsung site reviews support forums
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Operating systems
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risc single chip risc single chip rsc single-chip microprocessor developed fabricated international business machines ibm rsc feature-reduced single-chip implementation power1 multi-chip central processing unit cpu implemented power instruction set architecture isa used entry-level workstation models ibm rs/6000 family model 220 230 rsc operated frequencies 33 45 mhz three execution units fixed point unit floating point unit branch processor 8 kb unified instruction data cache like power1 memory controller i/o tightly integrated functional units responsible functions memory interface unit sequencer unit residing die processor rsc contains nine functional units fixed-point execution unit fxu floating-point execution unit fpu memory management unit mmu memory interface unit miu sequencer unit common on-chip processor unit cop instruction fetch unit instruction queue dispatch unit fixed point unit executes integer instructions generates addresses load store operations portions branch instructions three-stage pipeline consisting decode execute writeback stages instructions require several cycles execute stage completed floating point unit executes floating point instructions unlike power1 rsc register renaming capability due limited die area unit must fit save die area floating point multiply-add array 32 bits wide perform 64-bit double-precision operations operands broken two instruction passes twice multiply-add array floating point pipeline consists four stages decode multiply add writeback rsc 8 kb unified cache instead separate instruction large data caches like power1 unified cache two-way set associative uses store-through policy reload store miss least recently used lru replacement policy cache line size 64 bytes cache line sectored four quadwords 16 bytes quadword given valid bit cache directory cycle four words read two doublewords written memory data bus 72 bits wide 64 bits used data path 8 bits used error correcting code ecc memory interface unit manages bus performs ecc checks data coming processor ecc logic capable correcting single-bit errors compared power1 rsc memory data bus narrower uses industry standard simms instead custom memory cards rsc contained approximately one million transistors 14.9 mm 15.2 mm 226.48 mm die fabricated ibm complementary metal-oxide semiconductor cmos process minimal feature size 0.8 μm three levels wiring packaged 36 mm 36 mm ceramic pin grid array module 201 signal pins required 3.6 volt power supply consumed 4 watts operation 33 mhz
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Computer architecture
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common vulnerabilities exposures common vulnerabilities exposures cve system provides reference-method publicly known information-security vulnerabilities exposures national cybersecurity ffrdc operated mitre corporation maintains system funding national cyber security division united states department homeland security security content automation protocol uses cve cve ids listed mitre system well us national vulnerability database mitre corporation documentation defines cve identifiers also called cve names cve numbers cve-ids cves unique common identifiers publicly known information-security vulnerabilities publicly released software packages historically cve identifiers status candidate can- could promoted entries cve- however practice ended time ago identifiers assigned cves assignment cve number guarantee become official cve entry e.g cve may improperly assigned issue security vulnerability duplicates existing entry cves assigned cve numbering authority cna three primary types cve number assignments investigating vulnerability potential vulnerability helps acquire cve number early cve numbers may appear mitre nvd cve databases time days weeks months potentially years due issues embargoed cve number assigned issue made public cases entry researched written mitre due resource issues benefit early cve candidacy future correspondence refer cve number information getting cve identifiers issues open source projects available red hat cves software publicly released include betas pre-release versions widely used commercial software included publicly released category however custom-built software distributed would generally given cve additionally services e.g web-based email provider assigned cves vulnerabilities found service e.g xss vulnerability unless issue exists underlying software product publicly distributed cve database contains several fields standardized text description issue one common entry means entry number reserved mitre issue cna reserved number case cna requests block cve numbers advance e.g red hat currently requests cves blocks 500 cve number marked reserved even though cve may assigned cna time cve assigned mitre made aware i.e. embargo passes issue made public mitre researched issue written description entries show **reserved ** list urls information date entry created cves assigned directly mitre date mitre created cve entry cves assigned cnas e.g microsoft oracle hp red hat etc also date created mitre cna case cna requests block cve numbers advance e.g red hat currently requests cves blocks 500 entry date cve assigned cna following fields previously used older cve records longer used order support cve id beyond cve-year-9999 aka cve10k problem change made cve syntax 2014 took effect jan 13 2015 new cve-id syntax variable length includes cve prefix year arbitrary digits note variable length arbitrary digits begin four 4 fixed digits expand arbitrary digits needed calendar year example cve-yyyy-nnnn needed cve-yyyy-nnnnn cve-yyyy-nnnnnn also means changes needed previously assigned cve-ids include minimum 4 digits cve attempts assign one cve per security issue however many cases would lead extremely large number cves e.g several dozen cross-site scripting vulnerabilities found php application due lack use codice_1 insecure creation files codice_2 deal guidelines subject change cover splitting merging issues distinct cve numbers general guideline one first consider issues merged issues split type vulnerability e.g buffer overflow vs. stack overflow software version affected e.g one issue affects version 1.3.4 2.5.4 affects 1.3.4 2.5.8 would split reporter issue e.g alice reports one issue bob reports another issue issues would split separate cve numbers another example alice reports /tmp file creation vulnerability version 1.2.3 earlier examplesoft web browser addition issue several codice_2 file creation issues found cases may considered two reporters thus split two separate cves alice works examplesoft examplesoft internal team finds rest may merge'ed single cve conversely issues merged e.g bob finds 145 xss vulnerabilities exampleplugin exampleframework regardless versions affected may merged single cve mitre cve database searched cve list search nvd cve database searched search cve cce vulnerability database cve identifiers intended use respect identifying vulnerabilities common vulnerabilities exposures cve dictionary common names i.e. cve identifiers publicly known information security vulnerabilities cve ’ common identifiers make easier share data across separate network security databases tools provide baseline evaluating coverage organization ’ security tools report one security tools incorporates cve identifiers may quickly accurately access fix information one separate cve-compatible databases remediate problem users assigned cve identifier vulnerability encouraged ensure place identifier related security reports web pages emails
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Computer security
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oracle grid engine oracle grid engine previously known sun grid engine sge codine computing distributed networked environments grd global resource director grid computing computer cluster software system otherwise known batch-queuing system acquired part purchase gridware improved supported sun microsystems later oracle open source versions multiple commercial versions technology initially sun later oracle univa corporation october 22 2013 univa announced acquired intellectual property trademarks grid engine technology univa take support.. univa since evolved grid engine technology e.g improving scalability demonstrated 1 million core cluster aws announced june 24 2018 original grid engine open-source project website closed 2010 versions technology still available original sun industry standards source license projects forked original project code known son grid engine open grid scheduler univa grid engine grid engine typically used computer farm high-performance computing hpc cluster responsible accepting scheduling dispatching managing remote distributed execution large numbers standalone parallel interactive user jobs also manages schedules allocation distributed resources processors memory disk space software licenses grid engine used foundation sun grid utility computing system made available internet united states 2006 later becoming available many countries early version public cloud computing facility predating amazon aws instance feature sets date last sun releases 2009 earlier current feature information found web sites open source forks univa grid engine features 6.2 features sge include grid engine runs multiple platforms including aix bsd freebsd netbsd openbsd hp-ux irix linux mac os x solaris super-ux tru64 windows via sfu interix sua microsoft windows services unix execution hosts z/os progress typical grid engine cluster consists master host one execution hosts multiple shadow masters also configured hot spares take role master original master host crashes univa providing commercial support training univa grid engine oracle grid engine description historic options sun provided support contracts commercial version grid engine unix platforms windows professional services consulting training support provided sun partners sun partners georgetown university deliver grid engine administration classes bioteam runs short sge training workshops 1 2 days long users obtained community support grid engine mailing lists grid engine workshops held 2002 2003 2007 2009 2012 regensburg germany contains historic information recent deployment information specifically regarding commercial users available univa notable deployments sge include 2000 sun acquired gridware privately owned commercial vendor advanced computing resource management software offices san jose calif. regensburg germany later year sun offered free version gridware solaris linux renamed product sun grid engine 2001 sun made source code available adopted open source development model ports mac os x *bsd contributed non-sun open source developers 2010 purchase sun oracle grid engine 6.2 update 6 source code included binaries changes put back project source repository response grid engine community started open grid scheduler project continue develop maintain free implementation grid engine january 18 2011 announced univa recruited several principal engineers former sun grid engine team univa would developing forked version grid engine newly announced univa grid engine include commercial support would compete official version oracle grid engine oct 22 2013 univa announced acquired intellectual property trademarks pertaining grid engine technology univa take support oracle grid engine customers contains historic information products solutions longer available number sge add-ons available
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Distributed computing architecture
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tomoyo linux tomoyo linux stylised tomoyo linux linux kernel security module implements mandatory access control mac tomoyo linux mac implementation linux used increase security system also useful purely systems analysis tool launched march 2003 sponsored ntt data corporation march 2012 tomoyo linux focuses system behaviour tomoyo linux allows process declare behaviours resources needed achieve purpose protection enabled tomoyo linux restricts process behaviours resources allowed administrator main features tomoyo linux include tomoyo merged linux kernel mainline version 2.6.30 2009 june 10 currently one four standard linux security modules lsm along selinux apparmor smack tomoyo linux project started patch linux kernel provide mac porting tomoyo linux mainline linux kernel required introduction hooks lsm designed developed specifically support selinux label-based approach however hooks needed integrate remaining mac functionality tomoyo linux consequently project following two parallel development lines
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Operating systems
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robert e. drake robert edwin drake october 11 1923 – january 12 2006 american intelligence official deputy director national security agency 1978 1980 time highest ranking civilian agency joined armed services security agency 1949 eventually newly created national security agency 1952 nsa served overseas offices europe southeast asia hawaii also served position chief soviet east european analytic group deputy director operations retiring nsa 1978 returned independent consulting work intelligence work received national intelligence distinguished service medal national security agency meritorious exceptional civilian service awards defense department distinguished civilian service award central intelligence agency distinguished service medal alumnus carleton college minnesota george washington university national war college died heart failure 2006 aged 82
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Computer security
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remotefx microsoft remotefx microsoft brand name covers set technologies enhance visual experience microsoft-developed remote display protocol remote desktop protocol rdp remotefx first introduced windows server 2008 r2 sp1 based intellectual property microsoft acquired continued develop since acquiring calista technologies part overall remote desktop services workload remotefx components introduced windows server 2008 r2 sp1 include windows server 2012 following components added remotefx addition following components updated windows server 2016 rdp 10 following components added remotefx remotefx media streaming replaced multi media redirection mmr note mmr completely removed rdp 10 given remotefx media streaming works types video content whereas mmr worked windows server 2008 r2 remotefx codec could leveraged session hosting remote desktop session hosts vdi scenarios remote desktop virtualization hosts remotefx vgpu remotefx usb redirection features could used vdi scenarios remote desktop virtualization hosts windows 10 version 1511 brings remotefx client hyper-v removing dependency remote desktop services role generation 2 vms windows server 2012 r2 support remotefx windows server 2016 added support windows server 2012 features remotefx exception vgpu used without physical gpu present server gpu present server synthetic software-emulated gpu used render content gpu present server used hardware accelerate graphics via remotefx vgpu feature remotefx vgpu following requirements windows server 2008 r2 sp1 tested twelve virtual machines per gpu total twenty-four virtual machines two physical gpus although gpu meeting requirements capable using remotefx windows server catalog carries additional qualification define requirements server-qualified gpus specifications define gpus configuration requirements provide vm performance targets graphics cards meet typically professional workstation products ati/amd firepro v5800 v5900 v7800 v7900 v8800 v9800 nvidia quadro 2000 3800 4000 4800 5000 5800 6000 quadro fx 2800m 880m quadroplex 7000 tesla m2070q servers running remotefx vgpu need accommodate graphics cards either larger power supplies pcie slots alternatively connect existing servers external pcie expansion chassis
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Operating systems
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nsa playset nsa playset open source project inspired nsa ant catalog create accessible easy use tools security researchers surveillance tools recreated off-the-shelf open-source hardware software thus far nsa playset consists fourteen items code instructions found online project ’ homepage initial nsa ant catalog leak published der spiegel 2013 michael ossman founder great scott gadgets gave shout security researchers start working tools mentioned catalog recreate name nsa playset came originally dean pierce also contributor twilightvegetable gsm nsa playset anyone invited join contribute device requisites addition nsa playset similar already existing nsa ant project ease use silly name based original tool ’ name silly name requisite rule michael ossman came example given project ’ website example project similar foxacid maybe could call coyotemeth ease use part stems also nsa playset motto 10 year old ’ n't count
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Computer security
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wysiwym interaction technique see meant wysiwym text editing interaction technique emerged two projects university brighton allows users create abstract knowledge representations required semantic web using natural language interface natural language understanding nlu technology employed instead natural language generation nlg used highly interactive manner text editor accepts repeated refinement selected span text becomes increasingly less vacuous authored semantics using mouse text property held evolving text refined set options derived nlg built-in ontology invisible representation semantic knowledge created used multilingual document generation formal knowledge formation task requires formally specified information two projects brighton worked field conceptual authoring lay foundation research development semantic web authoring tool swat tool explored means developing knowledge base without prior experience controlled natural language tools
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Computational linguistics
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davegrohl davegrohl brute-force password cracker macos originally created 2010 password hash extractor since evolved standalone distributed password cracker supports standard mac os x user password hashes md4 sha-512 pbkdf2 used since os x lion also extract formatted popular password crackers like john ripper latest stable release designed specifically mac os x lion mountain lion davegrohl supports dictionary incremental attacks dictionary attack scan number pre-defined wordlists incremental attack count character set finds password distributed mode uses bonjour find server nodes local network therefore requires configuration
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Computer security
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shellshock software bug shellshock also known bashdoor family security bugs unix bash shell first disclosed 24 september 2014 shellshock could enable attacker cause bash execute arbitrary commands gain unauthorized access many internet-facing services web servers use bash process requests 12 september 2014 stéphane chazelas informed bash maintainer chet ramey discovery original bug called bashdoor working security experts developed patch fix issue assigned vulnerability identifier existence bug announced public bash updates fix ready distribution bug chazelas discovered caused bash unintentionally execute commands commands concatenated end function definitions stored values environment variables within days publication variety related vulnerabilities discovered ramey addressed series patches attackers exploited shellshock within hours initial disclosure creating botnets compromised computers perform distributed denial-of-service attacks vulnerability scanning security companies recorded millions attacks probes related bug days following disclosure potential compromise millions unpatched systems shellshock compared heartbleed bug severity shellshock bug affects bash program various unix-based systems use execute command lines command scripts often installed system default command-line interface analysis source code history bash shows bugs existed since bash version 1.03 released september 1989 shellshock privilege escalation vulnerability offers way users system execute commands unavailable happens bash function export feature whereby command scripts created one running instance bash shared subordinate instances feature implemented encoding scripts within table shared instances known environment variable list new instance bash scans table encoded scripts assembles one command defines script new instance executes command new instance assumes scripts found list come another instance verify verify command built properly formed script definition therefore attacker execute arbitrary commands system exploit bugs may exist bash command interpreter attacker way manipulate environment variable list cause bash run presence bug announced public bash updates fix ready distribution though took time computers updated close potential security issue within hour announcement bash vulnerability reports machines compromised bug 25 september 2014 botnets based computers compromised exploits based bug used attackers distributed denial-of-service ddos attacks vulnerability scanning kaspersky labs reported machines compromised attack dubbed thanks-rob conducting ddos attacks three targets identify 26 september 2014 shellshock-related botnet dubbed wopbot reported used ddos attack akamai technologies scan united states department defense 26 september security firm incapsula noted 17,400 attacks 1,800 web domains originating 400 unique ip addresses previous 24 hours 55 attacks coming china united states 30 september website performance firm cloudflare said tracking approximately 1.5 million attacks probes per day related bug 6 october widely reported yahoo servers compromised attack related shellshock issue yet next day denied shellshock specifically allowed attacks maintainer bash warned first discovery bug fix followed soon companies distributors informed matter publicly disclosed cve identifier cve-2014-6271 however release patch subsequent reports different yet related vulnerabilities 26 september 2014 two open-source contributors david a. wheeler norihiro tanaka noted additional issues even patching systems using recently available patches email addressed oss-sec list bash bug list wheeler wrote patch continues 'whack-a-mole job fixing parsing errors began first patch bash parser certain many many many vulnerabilities however rather general reasoning without actually presenting exploitation examples implied restricting bash functionality effect bash scripts wo n't work even intended harm users 27 september 2014 michał zalewski google inc. announced discovery bash vulnerabilities one based upon fact bash typically compiled without address space layout randomization 1 october zalewski released details final bugs confirmed patch florian weimer red hat posted 25 september indeed prevent done using fuzzing technique aid software utility known american fuzzy lop original form vulnerability involves specially crafted environment variable containing exported function definition followed arbitrary commands bash incorrectly executes trailing commands imports function vulnerability tested following command systems affected vulnerability commands display word vulnerable result bash executing command echo vulnerable embedded specially crafted environment variable named x discovered michał zalewski vulnerability relates parsing function definitions environment variables bash cause segfault also discovered michał zalewski relates parsing function definitions environment variables bash day original vulnerability published tavis ormandy discovered related bug demonstrated following code vulnerable system would execute command date unintentionally example system patch cve-2014-6271 cve-2014-7169 system displays syntax errors notifying user cve-2014-6271 prevented still writes file named 'echo working directory containing result 'date call system patched cve-2014-6271 cve-2014-7169 simply echo word date file echo created shown florian weimer todd sabin found bug relates out-of-bounds memory access error bash parser code example vulnerability leverages use multiple « eof declarations nested documents vulnerable system echo text cve-2014-7186 vulnerable redir_stack also found florian weimer off-by-one error bash parser code allowing out-of-bounds memory access example vulnerability leverages use multiple done declarations vulnerable system echo text cve-2014-7187 vulnerable word_lineno test requires shell supports brace expansion 24 september 2014 bash maintainer chet ramey provided patch version bash43-025 bash 4.3 addressing cve-2014-6271 already packaged distribution maintainers 24 september bash43-026 followed addressing cve-2014-7169 cve-2014-7186 discovered florian weimer red hat posted patch code unofficially 25 september ramey incorporated bash bash43-027.—these patches provided code helpful know compile rebuild new bash binary executable file patch file remaining source code files next day red hat officially presented according updates red hat enterprise linux another day fedora 21 canonical ltd. presented updates ubuntu long term support versions saturday 27 september sunday updates suse linux enterprise following monday tuesday end month mac os x updates appeared 1 october 2014 michał zalewski google inc. finally stated weimer code bash43-027 fixed first three bugs even remaining three published bash43-027 including two discoveries means earlier distribution updates updates required cover six issues also covered ibm hardware management console
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Computer security
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toobin' toobin nowiki /nowiki atari games video game originally released arcade game 1988 based recreational sport tubing later ported systems nes commodore amiga commodore 64 msx game boy color game player assumes control main characters bif jet guiding many winding rivers innertube game included part midway arcade treasures arcade party pak given remixed soundtrack also included 2012 compilation midway arcade origins game one 23 arcade games included midway arcade level pack lego dimensions unlocked using hidden arcade dock level follow lego brick road player competes river race computer another player player score increases swishing gates hitting characters cans collecting hidden letters spell toobin collecting treasures players try avoid obstacles pushing power-ups allow players carry multiple cans combinations gates increase score multiplier game three different classes five rivers total 15
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Computer architecture
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excavator microarchitecture amd excavator family 15h microarchitecture developed amd succeed steamroller family 15h use amd apu processors normal cpus october 12 2011 amd revealed excavator code name fourth-generation bulldozer-derived core excavator-based apu mainstream applications called carrizo released 2015 carrizo apu designed hsa 1.0 compliant excavator-based apu cpu variant named toronto server enterprise markets also produced excavator final revision bulldozer family two new microarchitectures replacing excavator year later excavator succeeded x86-64 zen architecture early 2017 excavator added hardware support new instructions avx2 bmi2 rdrand excavator designed using high density aka thin libraries normally used gpus reduce electric energy consumption die size delivering 30 percent increase efficient energy use excavator process 15 instructions per clock compared amd previous core steamroller three apu lines announced released plans steamroller 3rd gen bulldozer excavator 4th gen bulldozer architectures high-end desktop platforms excavator cpu desktop announced 2nd feb 2016 named athlon x4 845.in 2017 three desktop cpus athlon x4 9x0 launched come socket am4 tdp 65w fact apus graphics cores disabled amd opteron roadmaps 2015 show excavator-based toronto apu toronto cpu intended 1 processor 1p cluster applications
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Computer architecture
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cloud computing architecture cloud computing architecture refers components subcomponents required cloud computing components typically consist front end platform fat client thin client mobile device back end platforms servers storage cloud based delivery network internet intranet intercloud combined components make cloud computing architecture cloud computing architectures consist front-end platforms called clients cloud clients clients servers fat thick clients thin clients zero clients tablets mobile devices client platforms interact cloud data storage via application middleware via web browser virtual session zero ultra-thin client initializes network gather required configuration files tell os binaries stored entire zero client device runs via network creates single point failure network goes device rendered useless online network storage data stored accessible multiple clients cloud storage generally deployed following configurations public cloud private cloud community cloud combination three also known hybrid cloud order effective cloud storage needs agile flexible scalable multi-tenancy secure software-as-a-service saas service-model involves cloud provider installing maintaining software cloud users running software cloud internet intranet users client machines require installation application-specific software since cloud applications run cloud saas scalable system administrators may load applications several servers past customer would purchase load copy application servers saas customer access application without installing software locally saas typically involves monthly annual fee software service provides equivalent installed applications traditional non-cloud computing delivery applications software service four common approaches flex tenancy considered user adaptive saas paradigm designated multi-input four way manifold models systems based simplified encryption methods target listed data sequences multiple passes simplicity concept makes flex tenancy saas popular among without informatics processing experience basic maintenance custodial staff franchise businesses development service web based community shared development tools equivalent locally installed development tools traditional non-cloud computing delivery development tools data service web based design construct cloud data accessed defined api layer daas services often considered specialized subset software service saas offering platform service cloud computing service provides users application platforms databases service equivalent middleware traditional non-cloud computing delivery application platforms databases infrastructure service taking physical hardware going completely virtual e.g servers networks storage system management existing cloud equivalent infrastructure hardware traditional non-cloud computing method running cloud words businesses pay fee monthly annually run virtual servers networks storage cloud mitigate need data center heating cooling maintaining hardware local level generally cloud network layer offer
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Distributed computing architecture
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mcafee virusscan mcafee virusscan antivirus program created maintained mcafee inc. formerly known intel security network associates prior available standalone package included mcafee livesafe mcafee antivirus plus mcafee total protection additionally bskyb mcafee previously produced sky broadband branded version virusscan offered free sky digital customers upon broadband modem installation mcafee livesafe integrates antivirus firewall anti-spyware/anti-ransomware capabilities mcafee also produces enterprise-level product named virusscan enterprise mcafee designed use larger networks designed make management antivirus software multiple computers easier unlike home-user edition enterprise edition consists client application networked computers server application system installs updates configures settings client programs clients controlled using included epolicy orchestrator epo unified console control virusscan mcafee products november 2008 mcafee announced virusscan mac 8.6 earlier versions used name virex developed hjc software key changes virusscan 8.6 included leopard compatibility universal binary package ran intel powerpc-based macs access scanning apple mail support tests virus bulletin additional independent consumer-organizations mcafee virusscan fared well frequently failing detect common viruses review virusscan 2006 cnet criticized product due pronounced performance hits two three real-world performance tests users reviewing product reported encountering technical problems older versions virusscan engine use available cpu cycles reviewers described customer support mcafee products lacking support staff slow respond unable answer many questions april 21 2010 beginning approximately 2 pm gmt erroneous virus definition file update mcafee affected millions computers worldwide running windows xp service pack 3 update resulted removal windows system file codice_1 machines causing machines lose network access cases enter reboot loop mcafee rectified removing replacing faulty dat file version 5958 emergency dat file version 5959 posted fix affected machines consumer knowledgebase august 2012 update mcafee antivirus caused protection become turned users lose internet connections mcafee criticized notifying users promptly issues learned mcafee though well-known continues mixed reviews industry sources company prepared 2015 release series address current market conditions repositioning includes voice facial recognition authentication cloud-based data security
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Computer security
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philips nms-1205 br philips nms-1205 msx audio cartridge without bios using yamaha y8950 chip released 1984 nms-1205 sold europe msx personal computer cartridge featured fm sound synthesizer sound sampler adpcm 32 kb sample ram midi interface audio midi i/o connectors also built software music-box call musicbox fm sound synthesizer opl fm operator type-l compatible sound sampler 32kb sampleram adpcm unit midi interface in/out/thru built software music-box call musicbox note sold europe
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Computer architecture
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lio scsi target computing linux-io lio target open-source implementation scsi target become standard one included linux kernel internally lio initiate sessions instead provides one logical unit numbers luns waits scsi commands scsi initiator performs required input/output data transfers lio supports common storage fabrics including fcoe fibre channel ieee 1394 iscsi iscsi extensions rdma iser scsi rdma protocol srp usb included linux distributions native support lio qemu/kvm libvirt openstack makes lio also storage option cloud deployments lio maintained datera inc. silicon valley vendor storage systems software january 15 2011 lio scsi target engine merged linux kernel mainline kernel version 2.6.38 released march 14 2011 additional fabric modules merged subsequent linux releases competing generic scsi target module linux scst narrower purpose providing linux iscsi target older iet iscsi enterprise target stgt scsi target framework modules also enjoy industry support scsi standard provides extensible semantic abstraction computer data storage devices become lingua franca data storage systems scsi t10 standards define commands protocols scsi command processor sent scsi cdbs electrical optical interfaces various implementations scsi initiator endpoint initiates scsi session scsi target endpoint waits initiator commands executes required i/o data transfers scsi target usually exports one luns initiators operate lio linux scsi target implements generic scsi target provides remote access data storage device types prevalent storage fabrics protocols lio neither directly accesses data directly communicate applications lio provides highly efficient fabric-independent fabric-transparent abstraction semantics numerous data storage device types lio implements modular extensible architecture around versatile highly efficient parallelized scsi command processing engine scsi target engine implements semantics scsi target lio scsi target engine independent specific fabric modules backstore types thus lio supports mixing matching number fabrics backstores time lio scsi target engine implements comprehensive spc-3/spc-4 feature set support high-end features including scsi-3/scsi-4 persistent reservations prs scsi-4 asymmetric logical unit assignment alua vmware vsphere apis array integration vaai t10 dif etc lio configurable via configfs-based kernel api managed via command-line interface api targetcli concept scsi target n't narrowly restricted physical devices scsi bus instead provides generalized model receivers logical scsi fabric includes scsi sessions across interconnects physical scsi bus conceptually scsi target provides generic block storage service server scenario backstores provide scsi target generalized access data storage devices importing via corresponding device drivers backstores n't need physical scsi devices important backstore media types result lio provides generalized model export block storage fabric modules implement frontend scsi target encapsulating abstracting properties various supported interconnect following fabric modules available fibre channel ethernet fcoe fabric module allows transport fibre channel protocol fcp traffic across lossless ethernet networks specification supported large number network storage vendors part technical committee t11 fc-bb-5 standard lio supports standard ethernet nics fcoe fabric module contributed cisco intel released linux 3.0 july 21 2011 fibre channel high-speed network technology primarily used storage networking standardized technical committee t11 international committee information technology standards incits qlogic fibre channel fabric module supports 4- 8-gigabit speeds following hbas fibre channel fabric module low-level driver lld released linux 3.5 july 21 2012 linux 3.9 following qlogic hbas cnas also supported makes lio first open source target support 16-gigabit fibre channel firewire sbp-2 fabric module enables linux export local storage devices via ieee 1394 systems mount ordinary ieee 1394 storage device ieee 1394 serial bus interface standard high-speed communications isochronous real-time data transfer developed apple firewire late 1980s early 1990s macintosh computers supported firewire target disk mode since 1999 firewire sbp-2 fabric module released linux 3.5 july 21 2012 internet small computer system interface iscsi fabric module allows transport scsi traffic across standard ip networks carrying scsi sessions across ip networks iscsi used facilitate data transfers intranets manage storage long distances iscsi used transmit data local area networks lans wide area networks wans internet enable location-independent location-transparent data storage retrieval lio iscsi fabric module also implements number advanced iscsi features increase performance resiliency multiple connections per session mc/s error recovery levels 0-2 erl=0,1,2 lio supports standard ethernet nics iscsi fabric module released linux 3.1 october 24 2011 networks supporting remote direct memory access rdma use iscsi extensions rdma iser fabric module transport iscsi traffic iser permits data transferred directly remote scsi computer memory buffers without intermediate data copies direct data placement ddp using rdma rdma supported infiniband networks ethernet data center bridging dcb networks via rdma converged ethernet roce standard ethernet networks iwarp enhanced tcp offload engine controllers iser fabric module developed together datera mellanox technologies first released linux 3.10 june 30 2013 scsi rdma protocol srp fabric module allows transport scsi traffic across rdma see networks 2013 srp widely used iser although limited scsi peer-to-peer protocol whereas iscsi fully routable srp fabric module supports following mellanox host channel adapters hcas srp fabric module released linux 3.3 march 18 2012 2012 c't magazine measured almost 5000 mb/s throughput lio srp target one mellanox connectx-3 port 56 gbit/s fdr mode sandy bridge pci express 3.0 system four fusion-io iodrive pci express flash memory cards usb gadget fabric module enables linux export local storage devices via universal serial bus usb systems mount ordinary storage device usb designed mid-1990s standardize connection computer peripherals also become common data storage devices usb gadget fabric module released linux 3.5 july 21 2012 targetcli user space single-node management command line interface cli lio supports fabric modules based modular extensible architecture plug-in modules additional fabric modules functionality targetcli provides cli uses underlying generic target library well-defined api thus cli easily replaced complemented ui metaphors gui targetcli implemented python consists three main modules detailed instructions set lio targets found lio wiki targetcli lio included linux distributions per default overview popular ones together initial inclusion dates
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Operating systems
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peter t. brown peter t. brown executive director free software foundation fsf 2005 early 2011 come business management finance background began working organization 2001 comptroller promoted executive director 2005 departure bradley kuhn replaced john sullivan since joined software freedom conservancy director treasurer oxford england worked past bbc new internationalist became american citizen august 2017
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Operating systems
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enterprise privacy authorization language enterprise privacy authorization language epal formal language writing enterprise privacy policies govern data handling practices systems according fine-grained positive negative authorization rights submitted ibm world wide web consortium w3c 2003 considered recommendation 2004 lawsuit filed zero-knowledge systems claiming ibm breached copyright agreement worked together 2001 2002 create privacy rights markup language prml epal based prml means zero-knowledge argued co-owner standard
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Computer security
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.wps .wps file extension used
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Computer file systems
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msql msql mini sql lightweight database management system hughes technologies 1993–94 david hughes developed network monitoring management system called minerva design system required database management system store configuration working data enable future portability hughes elected use structured query language interface application database management system despite fact time free inexpensive sql database management implementation available hughes therefore developed translation program provided interface free postgres dbms use sql product named minisql msql time became clear postgres perform adequately low-specification systems used run minerva msql developed lightweight database management system right implementing limited subset sql standard performing well minimally specified hardware msql first low-cost sql-based database management system combined free linux operating system availability relatively powerful low-cost pc hardware development world wide web standards technologies msql important factor early development interactive dynamic web applications particularly period 1994–97 increasingly supplanted highly featured mysql msql large widespread install base late 1990s despite offered source code form strongly associated open source software msql never offered open source license msql provided free non-commercial use typical license commercial use 1997 would cost 170 compared five-digit purchase price full-featured competitors 1996 development msql began stagnate mysql arose fill void 1999 mysql surpassed msql popularity today msql less visibility time database system often licensed companies use products used end-users directly msql actively maintained developed primarily support licensees internal use within hughes technologies products projects still provided license allows use free charge non-commercial educational charitable activities msql 4.2 released april 2019. msql originally supported several host languages
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Databases
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identification friend foe identification friend foe iff radar-based identification system designed command control uses transponder listens interrogation signal sends response consisting unique signal identifies broadcaster enables military civilian air traffic control interrogation systems identify aircraft vehicles forces friendly determine bearing range interrogator iff may used military civilian aircraft iff first developed second world war arrival radar several infamous friendly fire incidents despite name iff positively identify friendly targets hostile ones iff interrogation receives reply invalid reply object identified friendly positively identified foe may instance friendly aircraft inoperative malfunctioning transponder addition many reasons friendly aircraft may properly reply iff iff tool within broader military action combat identification cid process attaining accurate characterization detected objects operational environment sufficient support engagement decision broadest characterization friend enemy neutral unknown cid reduce friendly fire incidents also contributes overall tactical decision-making successful deployment radar systems air defence world war ii combatants immediately confronted difficulty distinguishing friendly aircraft hostile ones time aircraft flown high speed altitude making visual identification impossible targets showed featureless blips radar screen led incidents battle barking creek britain air attack fortress koepenick germany already deployment chain home radar system ch raf considered problem iff robert watson-watt filed patents systems 1935 1936 1938 researchers bawdsey manor began experiments reflectors consisting dipole antennas tuned resonate primary frequency ch radars pulse ch transmitter hit aircraft antennas would resonate short time increasing amount energy returned ch receiver antenna connected motorized switch periodically shorted preventing producing signal caused return ch set periodically lengthen shorten antenna turned practice system found unreliable use return highly dependent direction aircraft moving relative ch station often returned little additional signal suspected system would little use practice turned case raf turned entirely different system also planned consisted set tracking stations using hf/df radio direction finders aircraft radios modified send 1 khz tone 14 seconds every minute allowing stations ample time measure aircraft bearing several stations assigned sector air defence system sent measurements plotting station sector headquarters used triangulation determine aircraft location known pip-squeak system worked labour-intensive display information directly radar operators system worked directly radar clearly desirable first active iff transponder transmitter/responder iff mark used experimentally 1939 used regenerative receiver fed small amount amplified output back input strongly amplifying even small signals long single frequency like morse code unlike voice transmissions tuned signal ch radar 20–30 mhz amplifying strongly broadcast back aircraft antenna since signal received time original reflection ch signal result lengthened blip ch display easily identifiable testing found unit would often overpower radar produce little signal seen time new radars introduced using new frequencies instead putting mark production new iff mark ii introduced early 1940 mark ii series separate tuners inside tuned different radar bands stepped using motorized switch automatic gain control solved problem sending much signal mark ii technically complete war began lack sets meant available quantity small number raf aircraft carried time battle britain pip-squeak kept operation period battle ended iff mark ii quickly put full operation pip-squeak still used areas land ch cover well emergency guidance system even 1940 complex system mark ii reaching limits new radars constantly introduced 1941 number sub-models introduced covered different combinations radars common naval ones instance used raf introduction radars based microwave-frequency cavity magnetron rendered obsolete simply way make responder operating band using contemporary electronics 1940 english engineer freddie williams suggested using single separate frequency iff signals time seemed pressing need change existing system introduction magnetron work concept began telecommunications research establishment iff mark iii become standard western allies war mark iii transponders designed respond specific 'interrogators rather replying directly received radar signals interrogators worked limited selection frequencies matter radar paired system also allowed limited communication made including ability transmit coded 'mayday response iff sets designed built ferranti manchester williams specifications equivalent sets manufactured us initially copies british sets allied aircraft would identified upon interrogation radar iff sets obviously highly classified thus many wired explosives event aircrew bailed crash landed jerry proc reports alongside switch turn unit iff destruct switch prevent capture enemy many pilot chose wrong switch blew iff unit thud contained explosion acrid smell burning insulation cockpit deter many pilots destroying iff units time time eventually self destruct switch secured thin wire prevent accidental use fug 25a erstling english firstborn debut developed germany 1940 two bands tuned low-vhf band 125 mhz used freya radar low-uhf-banded 550–580 mhz used würzburg flight transceiver set selected day code ten bits dialled unit start identification procedure ground operator switched pulse frequency radar 3,750 hz 5,000 hz airborne receiver decoded started transmit day code radar operator would see blip lengthen shorten given code ensuring spoofed iff transmitter worked 168 mhz power 400 watts pep system included way ground controllers determine whether aircraft right code include way transponder reject signals sources british military scientists found way exploiting building iff transmitter called perfectos designed trigger response fug 25a system vicinity fug 25a responded 168 mhz frequency signal received antenna system ai mk iv radar originally operated 212 mhz comparing strength signal different antennas direction target could determined mounted mosquitos perfectos severely limited german use fug 25a united states naval research laboratory working iff system since war used single interrogation frequency like mark iii separate responder frequency responding different frequency several practical advantages notably response one iff trigger another requires complete transmitter responder side circuitry contrast greatly simplified system used british designs technique known cross-band transponder mark ii revealed 1941 tizard mission decided use take time improve experimental system result became mark iv main difference earlier models worked higher frequencies around 600 mhz allowed much smaller antennas unfortunately also turned close frequencies used german würzburg radar concerns would triggered radar transponder responses would picked radar display thereby give away operational frequencies led us–british effort make improved model mark v also known united nations beacon unb moved still higher frequencies around 1 ghz operational testing complete war ended time testing finished 1948 much improved mark x beginning testing mark v abandoned mark x started purely experimental device operating frequencies 1 ghz development continued decided introduce encoding system known selective identification feature sif sif allowed return signal contain 12 pulses representing four octal digits 3 bits depending timing interrogation signal sif would respond several ways mode 1 indicated type aircraft mission cargo instance mode 2 returned tail code mark x began introduced early 1950s period great expansion civilian air transport system decided use slightly modified mark x sets aircraft well sets included new mode 3 paired civilian mode operated similar original mode 2 returned four-digit identifier mode 3 identical normally referred mode 3/a addition mode c returned altitude encoded single 12-bit number gillham code represented altitude number x 100 feet 1200 mode b specified never used current iff system mark xii works frequencies mark x supports military civilian modes main reason creation mark xii addition military mode 4 mark xii transponders would respond properly formed interrogation signal broadcasting reply could picked receiver using triangulation enemy could determine location transponder british already used technique germans wwii used usaf vpaf aircraft vietnam war mode 4 started interrogation similar mode 3 followed encoded pulse chain similar one used mode 3/a receiver side transponder checks code known day code responds two match pulses reply delayed based received code largely eliminates ability enemy trigger transponder 1980s new civilian mode mode added allowed greatly increased amounts data encoded returned signal used encode location aircraft navigation system basic part traffic collision avoidance system tcas system allows commercial aircraft know location aircraft area avoid without need ground operators basic concepts mode militarized mode 5 simply cryptographically encoded version mode data iff world war ii soviet military systems 1946 1991 used coded radar signals called cross-band interrogation cbi automatically trigger aircraft transponder aircraft illuminated radar radar-based aircraft identification also called secondary radar military civil usage primary radar bouncing rf pulse aircraft determine position george charrier working rca filed patent iff device 1941 required operator perform several adjustments radar receiver suppress image natural echo radar receiver visual examination iff signal would possible 1943 donald barchok filed patent radar system using acronym iff text parenthetic explanation indicating acronym become accepted term 1945 emile labin edwin turner filed patents radar iff systems outgoing radar signal transponder reply signal could independently programmed binary codes setting arrays toggle switches allowed iff code varied day day even hour hour united states nato countries started using system called mark xii late twentieth century britain implemented iff system compatible standard developed program compatible system known successor iff siff modes 4 5 designated use nato forces
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Computer security
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zero page cp/m zero page base page data structure used cp/m systems programs communicate operating system 8-bit cp/m versions located first 256 bytes memory hence name equivalent structure dos program segment prefix psp 8-bit cp/m following structure cp/m-86 structure
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Operating systems
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directfb directfb direct frame buffer software library small memory footprint provides graphics acceleration input device handling abstraction layer integrated windowing system support translucent windows multiple display layers top linux framebuffer without requiring kernel modifications directfb free open-source software subject terms gnu lesser general public license lgpl library allows developers alternative full x window system x11 server used unix-like operating systems directfb allows applications talk directly video hardware direct api speeding simplifying graphic operations often used games embedded systems developers circumvent overhead full x window system server implementation 2006 version directfb included software stack ce linux forum audio/video graphics specification v2 directfb host xdirectfb rootless x server implementation uses directfb windows x11 top-level windows xdirectfb interface mimics x11 interface directfb api simplify running applications written x11 directfb directfbgl opengl extension directfb/xdirectfb uses direct rendering infrastructure dri mesa 3d library support opengl hardware acceleration among products use directfb linuxtv ben nanonote unreleased palm foleo mobile companion webos operating system panasonic viera connect tvs philips tvs based jointspace
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Operating systems
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sparc t3 sparc t3 microprocessor previously known ultrasparc t3 codenamed rainbow falls also known ultrasparc kt niagara-3 development multithreading multi-core cpu produced oracle corporation previously sun microsystems officially launched 20 september 2010 member sparc family successor ultrasparc t2 overall single socket multi-socket throughput increased t3 processor systems providing superior throughput half cpu socket requirements predecessor throughput spec cint2006 rate increased single socket t3-1 platform comparison predecessor t2+ processor dual-socket t5240 platform simulated web serving workloads dual-socket based sparc t3 systems benchmarked better performance quad-socket previous generation ultrasparc t2+ systems well competing dual quad socket contemporary systems online publication register incorrectly reported june 2008 microprocessor would 16 cores 16 threads september 2009 published roadmap instead showed 8 threads per core hot chips 21 conference sun revealed chip total 16 cores 128 threads according isscc 2010 presentation 16-core sparc soc processor enables 512 threads 4-way glueless system maximize throughput 6mb l2 cache 461gb/s 308-pin serdes i/o 2.4tb/s support required bandwidth six clock four voltage domains well power management circuit techniques optimize performance power variability yield trade-offs across 377mm die support ultrasparc t3 confirmed july 16 2010 arcbot twitter noted unpublished psarc/2010/274 revealed new -xtarget value ultrasparc t3 included opensolaris oracle openworld san francisco september 20 2010 processor officially launched sparc t3 dropping ultra prefix name accompanied new systems new reported benchmarks claiming world-record performance varied real-world application benchmarks released full system disclosures internationally recognized spec benchmarks also released full system disclosures oracle disclosed sparc t3 built 40 nm process sparc t3 features include release sparc t3 chip new brand oracle sparc t-series servers introduced market effectively replacing cmt ultrasparc t2/t2 plus machines previous sparc enterprise product line fewer physical products former server line refreshed t3 chip reducing total number servers respectively four like prior t1 t2 t2+ processors t3 supports hyper-privileged execution mode t3 supports 128 oracle vm server sparc domains feature formerly known logical domains sparc t3 processor effectively two t2+ processors single die t3
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Computer architecture
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nop slide computer security nop slide nop sled nop ramp sequence nop no-operation instructions meant slide cpu instruction execution flow final desired destination whenever program branches memory address anywhere slide technique sees common usage software exploits used direct program execution branch instruction target known precisely notable applications include defensive programming strategies emc-aware programming nop slide function consists list canonical nop instructions presence code suspicious easy automatically detect reason practical nop slides often composed non-canonical nop instructions moving register adding zero instructions affect program state inconsequentially makes much difficult identify entropy nop slide dependent upon constraints placed determined certain registers use say set known value next use instructions manipulate arbitrarily may used nop slide additionally alignment nop slide instruction pointer deterministic multi-byte instructions used nop slide without regard results unaligned execution input providing attack vector nop slide payload introduced filtered accepting printable characters field possible instructions inclusion limited instructions part architecture extension sse may frequently irrelevant program state used nop slide targeting computer extension supported many techniques exist detect presence nop slides memory example 2005 greek researchers found easily detected checking whether memory image contains lengthy sequence bytes starting offset within sequence valid leads execution place
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Computer security
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digital guardian digital guardian american data loss prevention software company provides software end-user level corporate networks servers databases cloud digital guardian designed see stop malicious actions users malware endpoints puts data events context applies granular set rules protect threats company holds 20 patents technology customers include 300 global 2000 companies well seven 10 largest brands world considered leader global data loss prevention market company founded 2003 name verdasys start flagship product digital guardian data-centric security platform monitoring encrypting proprietary sensitive information passing desktop laptop enterprise server 2008 verdasys launched sitetrust encryption software service banks brokerages big companies served customers internet legally liable losses online fraud client-side software package turned whenever user visited website protected sitetrust service spawned new instance user web browser shutting malware creating secure space around communications protected site agreement verdasys fidelis security systems fidelis cybersecurity 2010 enabled customers acquire implement integrated solution consisting fidelis xps network appliances digital guardian enterprise information protection single offering verdasys early 2012 verdasys expanded data leak prevention portfolio cloud help enterprises protect data stored networks reduce costs one customers large insurance company requested verdasys take job monitoring protecting data verdasys introduced two new offerings managed service information protection msip information protection service ipaas offering data protection managed service digital guardian platform completed eal2+ evaluation communications security establishment common criteria evaluation certification scheme december 2012 verdasys introduced data connector 2013 contained malware threats detected fireeye platform verdasys connector malware handled manually december gartner magic quadrant placed digital guardian among five leaders global data loss prevention market ken levine previously mcafee executive joined company ceo 2014 focused simplifying product march verdasys raised 12 million venture funding bringing company total raised capital 69 million funding round led existing investors ge pension trust fairhaven capital new individual investment brookline venture partners 2014 also year several major partnerships acquisitions march identity finder llc partnered verdasys bringing sensitive data manager capable automatically finding classifying securing sensitive information august verdasys changed name digital guardian increased staff 150 time security software installed two million servers laptops devices october company acquired armor5 provider cloud control solutions focusing specifically preventing employees bring mobile device work copying removing company files data may 2015 company acquired savant protection enabling organizations deploy unique agent whitelisting applications used particular endpoint blue coat systems launched alliance ecosystem endpoint detection response july 2015 digital guardian among alliance-founding members ecosystem allows sharing actionable intelligence gathered endpoint security solutions also july consulting firm atos digital guardian partnered deliver atos ’ cloud-based data loss prevention service october company bought code green networks based silicon valley contributed true dlp gear acquisition code green networks provided digital guardian network discovery cloud data loss prevention company added 100 customers 2015 bringing total count nearly 500 including general electric dupont end year digital guardian announced 66 million new funding firm largest round since founded returning investors round ge pension trust advised ge asset management fairhaven capital partners loring wolcott coolidge special situation funds brookline venture partners new investors llr partners mass mutual ventures corporate venture capital arm massachusetts mutual life insurance company venture unit siemens financial services company raised 135 million since founding january 2016 gartner magic quadrant enterprise data loss prevention placed digital guardian among four leaders global data loss prevention market fourth consecutive time bostinno included digital guardian among 16 boston tech firms watch 2016 company placed 148th list top 500 cybersecurity firms world released cybersecurity ventures 2015 data loss prevention software platform digital guardian integrates content context location awareness along encryption data level controls reduce risk information loss misuse purposeful data theft host-based security technology empowers organizations monitor control audit prevent data wrongful disclosure malicious theft automatically enforcing data security policies procedures scalable platform provides multiple independent layers protection enable secure data sharing across physical virtual mobile cloud environments architecture platform three parts digital guardian allows businesses host manage premise choose managed security programs deployed managed service digital guardian collect actual data rather aggregates metadata files documents watches patterns activity metadata encrypted hashed digitally signed transferred digital guardian hosting facilities via fips 140-2 certified messaging protocol digital guardian provides updated analytics alerts reports administrators continuously monitor data application system access usage whether end users online offline virtual environments organizations apply specific risk-based policy controls adhere data governance compliance rules example health service organization cigna uses digital guardian software monitor ports encrypt data transfers employees try transfer files usb flash drive prompted type reasons transfer data actually transferred compared reasons digital guardian also provides support sharefile file sharing storage systems extending data loss prevention capabilities organizations support virtual desktops
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Computer security
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darkmatter emirati company darkmatter founded united arab emirates uae 2014 2015 cybersecurity company company describes purely defensive company several whistleblowers alleged involved offensive cybersecurity cracking colloquially hacking including behalf emirati government darkmatter founded either 2014 2015 faisal al-bannai founder mobile phone vendor axiom telecom son major general dubai police force around 2014 zeline 1 wholly owned subsidiary darkmatter became active finland darkmatter public launch came 2015 2nd annual arab future cities summit time company advertised capabilities including network security bug sweeping promised create new secure mobile phone handset promoted digital defense intelligence service uae 2016 darkmatter replaced cyberpoint contractor project raven also 2016 darkmatter sought smartphone development expertise oulu finland darkmatter recruited several finnish engineers early 2018 darkmatter turnover hundreds millions us dollars eighty per cent work uae government related organisations including nesa developed smartphone model called katim arabic silence addition recruiting via conventional routes personal referrals stalls trade shows e.g black hat darkmatter headhunts staff u.s. national security agency poached competitors staff contracted uae government happened cyberpoint employees project raven confidential initiative help uae surveil governments militants human rights activists team included former u.s. intelligence agents applied training hack phones computers belonging project raven victims operation based converted mansion abu dhabi nicknamed villa around 2014 2016 cyberpoint supplied u.s.-trained contractors project raven 2016 news reports emerged cyberpoint contracted italian spyware company hacking team damaged cyberpoint reputation defensive cybersecurity firm reportedly dissatisfied relying upon u.s.-based contractor uae replaced cyberpoint darkmatter contractor darkmatter induced several cyberpoint staff move darkmatter project raven reportedly expanded surveillance include targeting americans potentially implicating american staff unlawful behaviour 2016 project raven bought tool called karma karma able remotely exploit apple iphones anywhere world without requiring interaction part iphone owner apparently achieved exploiting zero-day vulnerability device imessage app project raven operatives able view passwords emails text messages photos location data compromised iphones people whose mobile phones deliberately compromised using karma reportedly include 2017 apple patched security vulnerabilities exploited karma reducing tool effectiveness 2016 two darkmatter whistleblowers multiple security researchers expressed concerns darkmatter intended become certificate authority ca would give technical capability create fraudulent certificates would allow fraudulent websites software updates convincingly masquerade legitimate ones capabilities misused would allow darkmatter easily deploy rootkits targets devices decrypt https communications firefox users via man-in-the-middle attacks 28 december 2017 darkmatter requested mozilla include trusted ca firefox web browser year mozilla reviewers addressed concerns darkmatter technical practices eventually questioning basis whether darkmatter met baseline requirements inclusion 30 january 2019 reuters published investigations describing darkmatter project raven mozilla reviewers noted investigation findings subsequently electronic frontier foundation eff others asked mozilla deny darkmatter request basis investigation showed darkmatter untrustworthy therefore liable misuse capabilities mozilla public consultation deliberations ongoing july 2019 mozilla prohibited government united arab emirates operating one internet security gatekeepers following reports cyber espionage program run abu dhabi-based darkmatter staff leading clandestine hacking operation august 2019 google blocked websites approved darkmatter reuters reported firm ’ involvement hacking operation led united arab emirates google previously said websites certified darkmatter would marked unsafe chrome android browsers
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Computer security
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ipod touch 7th generation seventh-generation ipod touch stylized marketed ipod touch colloquially known ipod touch 7g ipod touch 7 ipod touch 2019 multipurpose handheld device designed marketed apple inc. touchscreen-based user interface successor ipod touch 6th generation becoming first major update ipod touch since 2015 released online apple store may 28 2019 seventh-generation ipod touch features ios apple mobile operating system user interface ios based concept direct manipulation using multi-touch gestures interface control elements consist sliders switches buttons interaction os includes gestures swipe tap pinch reverse pinch specific definitions within context ios operating system multi-touch interface internal accelerometers used applications respond shaking device one common result undo command rotating vertically one common result switching portrait landscape mode seventh-generation ipod touch introduced may 28 2019 running latest ios version 12.3.1 play music movies television shows audiobooks podcasts sort media library songs artists albums videos playlists genres composers podcasts audiobooks compilations scrolling achieved swiping finger across screen alternatively headset controls used pause play skip repeat tracks however earpods come seventh-generation ipod touch include remote microphone voice control feature also used identify track play songs playlist specific artist create genius playlist apple a10 system-on-chip seventh-generation ipod touch enables advanced features predecessors includes arkit applications group facetime functionality seventh-generation ipod touch features apple a10 processor m10 motion coprocessor processor used apple iphone 7 apple ipad 2018 however underclocked 1.64 ghz 2.34 ghz uses two four cores making ipod touch weaker devices chip seventh-generation ipod touch features front rear camera systems sixth-generation device includes 8mp rear facing camera capable recording video 1080p resolution 30fps slow-motion video 720p 120fps camera also supports different photo features burst photos hdr photos panoramic photos front facing camera facetime hd camera capable taking photos 1.2mp recording video 720p 30fps camera also features auto hdr video recordings burst photo capabilities device first ipod touch come 256 gb storage option— highest capacity ever offered ipod surpassing 160gb capacity sixth-generation ipod classic discontinued 2014 seventh-generation ipod touch ships apple earpods apple lightning usb charging cable device also supports apple airpods earpods lightning connector
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Operating systems
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pki resource query protocol pki resource query protocol prqp internet protocol used obtaining information services associated x.509 certification authority described draft document pkix working group released 2013-oct-23 proposed standard rfc7030 created massimiliano pala solve interoperability usabilities issues among pkis specifically addressing certain problems associated finding services data repositories associated ca messages communicated via prqp encoded asn.1 usually communicated http present ever services protocols defined address different needs users administrators pkis deployment new applications services need access pki resources provided different organizations critical application needs told find services new certificate encounters therefore application needs properly configured filling complex configuration options whose meaning mostly unknown average user likely administrator well prqp protocol addresses interoperability trust building issues among separate pki islands fact provides dynamic method capable provide timely information provided services available pki resources also used help painless rollover services e.g switching crls ocsp certificate validation moreover prqp allows pki management dynamically choose services provided based faced challenges infrastructure deployment words prqp thought similar concept dns pki resources pkis three primary methods clients obtain pointers pki data adopting specific certificate extensions looking easily accessible repositories e.g dns local database etc adapting existing protocols e.g web services provide pointers published data ca could use authority information access aia subject information access sia extensions detailed rfc-3280 former provide information issuer certificate latter carries information inside ca certificates offered services subject information access extension carry uri point certificate repositories timestamping services hence extension allows access services several different protocols e.g http ftp ldap smtp although encouraged usage aia sia extension still widely deployed two main reasons first lack support extensions available clients second reason extensions static i.e modifiable indeed modify add new extensions order users applications aware new services dismissal certificate must re-issued would feasible end entities ee certificates except periodic reissuing would feasible ca certificate ca could retain public key name add new values aia extension new certificate users fetch ca cert regularly rather caching would enable become aware new services although possible almost every available clients look cas certificates already stored clients local database case since urls tend change quite often certificates persist longer time frames experience suggests extensions invariably point urls longer exist moreover considering fact entity issues certificates one runs services may infeasible issuing ca reissue certificate case server url changes therefore wise depend usage aia sia extensions available services repositories lookup srv record dns service record technique thought provide pointers servers directly dns rfc 1035 defined rfc 2782 introduction type record allows administrators perform operations rather similar ones needed solve problem prqp addresses i.e easily configurable pki discovery service basic idea client query dns specific srv record example srv-aware ldap client wants discover ldap server certain domain performs dns lookup _ldap._tcp.example.com _tcp means client requesting tcp enabled ldap server returned record contains information priority weight port target service domain problem adoption mechanism pkis unlike dns usually fixed requirement name space used time correspondence dns structure data contained certificates exception domain component dc attributes used certificate subject dc attributes used specify domain components dns name example domain name example.com could represented using dc=com dc=example format ca subject field would make use format issuer field would allow client applications perform dns lookups provided domain information repositories services could stored however currently practice different fact extremely difficult client map digital certificates dns records dc format widely adopted existing cas example one certificate ie7/outlook certificates store uses domain components provide mapping certificate internet domain
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Internet protocols
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access control fields physical security information security access control ac selective restriction access place resource act accessing may mean consuming entering using permission access resource called authorization locks login credentials two analogous mechanisms access control geographical access control may enforced personnel e.g. border guard bouncer ticket checker device turnstile may fences avoid circumventing access control alternative access control strict sense physically controlling access system checking authorized presence see e.g ticket controller transportation variant exit control e.g shop checkout country term access control refers practice restricting entrance property building room authorized persons physical access control achieved human guard bouncer receptionist mechanical means locks keys technological means access control systems like mantrap within environments physical key management may also employed means managing monitoring access mechanically keyed areas access certain small assets physical access control matter access control system determines allowed enter exit allowed exit enter allowed enter exit historically partially accomplished keys locks door locked someone key enter door depending lock configured mechanical locks keys allow restriction key holder specific times dates mechanical locks keys provide records key used specific door keys easily copied transferred unauthorized person mechanical key lost key holder longer authorized use protected area locks must re-keyed electronic access control uses computers solve limitations mechanical locks keys wide range credentials used replace mechanical keys electronic access control system grants access based credential presented access granted door unlocked predetermined time transaction recorded access refused door remains locked attempted access recorded system also monitor door alarm door forced open held open long unlocked credential presented reader reader sends credential information usually number control panel highly reliable processor control panel compares credential number access control list grants denies presented request sends transaction log database access denied based access control list door remains locked match credential access control list control panel operates relay turn unlocks door control panel also ignores door open signal prevent alarm often reader provides feedback flashing red led access denied flashing green led access granted description illustrates single factor transaction credentials passed around thus subverting access control list example alice access rights server room bob alice either gives bob credential bob takes access server room prevent two-factor authentication used two factor transaction presented credential second factor needed access granted another factor pin second credential operator intervention biometric input three types factors authenticating information passwords common means verifying user identity access given information systems addition fourth factor authentication recognized someone know whereby another person knows provide human element authentication situations systems set allow scenarios example user may password forgotten smart card scenario user known designated cohorts cohorts may provide smart card password combination extant factor user question thus provide two factors user missing credential giving three factors overall allow access credential physical/tangible object piece knowledge facet person physical enables individual access given physical facility computer-based information system typically credentials something person knows number pin something access badge something biometric feature combination items known multi-factor authentication typical credential access card key-fob newer software also turn users smartphones access devices many card technologies including magnetic stripe bar code wiegand 125 khz proximity 26-bit card-swipe contact smart cards contactless smart cards also available key-fobs compact id cards attach key ring biometric technologies include fingerprint facial recognition iris recognition retinal scan voice hand geometry built-in biometric technologies found newer smartphones also used credentials conjunction access software running mobile devices addition older traditional card access technologies newer technologies near field communication nfc bluetooth low energy also potential communicate user credentials readers system building access access control point door turnstile parking gate elevator physical barriers granting access electronically rely users credentials biometric fingerprints face card readers pin typically access point door electronic advanced access control door contain several elements basic stand-alone electric lock lock unlocked operator switch automate operator intervention replaced reader reader could keypad code entered could card reader could biometric reader readers usually make access decision send card number access control panel verifies number access list monitor door position magnetic door switch used concept door switch unlike refrigerators car doors generally entry controlled exit uncontrolled cases exit also controlled second reader used opposite side door cases exit controlled free exit device called request-to-exit rex used request-to-exit devices push-button motion detector button pushed motion detector detects motion door door alarm temporarily ignored door opened exiting door without electrically unlock door called mechanical free egress important safety feature cases lock must electrically unlocked exit request-to-exit device also unlocks door access control decisions made comparing credential access control list look-up done host server access control panel reader development access control systems seen steady push look-up central host edge system reader predominant topology circa 2009 hub spoke control panel hub readers spokes look-up control functions control panel spokes communicate serial connection usually rs-485 manufactures pushing decision making edge placing controller door controllers ip enabled connect host database using standard networks access control readers may classified functions able perform readers may additional features lcd function buttons data collection purposes i.e clock-in/clock-out events attendance reports camera/speaker/microphone intercom smart card read/write support access control readers may also classified type identification technology 1 serial controllers controllers connected host pc via serial rs-485 communication line via 20ma current loop older systems external rs-232/485 converters internal rs-485 cards installed standard pcs rs-485 communication ports advantages disadvantages 2 serial main sub-controllers door hardware connected sub-controllers a.k.a door controllers door interfaces sub-controllers usually make access decisions instead forward requests main controllers main controllers usually support 16 32 sub-controllers advantages disadvantages 3 serial main controllers intelligent readers door hardware connected directly intelligent semi-intelligent readers readers usually make access decisions forward requests main controller connection main controller unavailable readers use internal database make access decisions record events semi-intelligent reader database function without main controller used areas require high security main controllers usually support 16 64 readers advantages disadvantages ones listed second paragraph 4 serial controllers terminal servers spite rapid development increasing use computer networks access control manufacturers remained conservative rush introduce network-enabled products pressed solutions network connectivity many chose option requiring less efforts addition terminal server device converts serial data transmission via lan wan advantages disadvantages rs-485-related advantages disadvantages also apply 5 network-enabled main controllers topology nearly described second third paragraphs advantages disadvantages apply on-board network interface offers couple valuable improvements transmission configuration user data main controllers faster may done parallel makes system responsive interrupt normal operations special hardware required order achieve redundant host pc setup case primary host pc fails secondary host pc may start polling network controllers disadvantages introduced terminal servers listed fourth paragraph also eliminated 6 ip controllers controllers connected host pc via ethernet lan wan advantages disadvantages 7 ip readers readers connected host pc via ethernet lan wan advantages disadvantages advantages disadvantages ip controllers apply ip readers well common security risk intrusion access control system simply following legitimate user door referred tailgating often legitimate user hold door intruder risk minimized security awareness training user population active means turnstiles high security applications risk minimized using sally port sometimes called security vestibule mantrap operator intervention required presumably assure valid identification second common risk levering door open relatively difficult properly secured doors strikes high holding force magnetic locks fully implemented access control systems include forced door monitoring alarms vary effectiveness usually failing high false positive alarms poor database configuration lack active intrusion monitoring newer access control systems incorporate type door prop alarm inform system administrators door left open longer specified length time third common security risk natural disasters order mitigate risk natural disasters structure building quality network computer equipment vital organizational perspective leadership need adopt implement hazards plan incident response plan highlights incident plan determined national incident management system must include pre-incident planning incident actions disaster recovery action review similar levering crashing cheap partition walls shared tenant spaces divisional wall vulnerability vulnerability along lines breaking sidelights spoofing locking hardware fairly simple elegant levering strong magnet operate solenoid controlling bolts electric locking hardware motor locks prevalent europe us also susceptible attack using doughnut shaped magnet also possible manipulate power lock either removing adding current although access control systems incorporate battery back-up systems locks almost always located secure side door access cards proven vulnerable sophisticated attacks enterprising hackers built portable readers capture card number user proximity card hacker simply walks user reads card presents number reader securing door possible card numbers sent clear encryption used counter dual authentication methods card plus pin always used many access control credentials unique serial numbers programmed sequential order manufacturing known sequential attack intruder credential used system simply increment decrement serial number find credential currently authorized system ordering credentials random unique serial numbers recommended counter threat finally electric locking hardware still mechanical keys fail-over mechanical key locks vulnerable bumping need know principle enforced user access controls authorization procedures objective ensure authorized individuals gain access information systems necessary undertake duties computer security general access control includes authentication authorization audit narrow definition access control would cover access approval whereby system makes decision grant reject access request already authenticated subject based subject authorized access authentication access control often combined single operation access approved based successful authentication based anonymous access token authentication methods tokens include passwords biometric scans physical keys electronic keys devices hidden paths social barriers monitoring humans automated systems access-control model entities perform actions system called subjects entities representing resources access may need controlled called objects see also access control matrix subjects objects considered software entities rather human users human users effect system via software entities control although systems equate subjects user ids processes started user default authority level control fine-grained enough satisfy principle least privilege arguably responsible prevalence malware systems see computer insecurity models example object-capability model software entity potentially act subject object access-control models tend fall one two classes based capabilities based access control lists acls capability-based acl-based models mechanisms allow access rights granted members group subjects often group modeled subject access control systems provide essential services authorization identification authentication access approval accountability access accounts enforced many types controls telecommunication term access control defined u.s. federal standard 1037c following meanings definition depends several technical terms federal standard 1037c object-oriented programming languages access control part apparatus achieving encapsulation one four fundamentals object-oriented programming goal establish clear separation interface visible accessible parts class implementation internal representation helper methods also known data hiding ensures exclusive data access class members variables methods protects object integrity preventing corruption client programmer/ client classes rule thumb use restrictive access level data unless compelling reason expose also helps reduce interdependencies classes leading lower coupling fewer regression bugs object-oriented programming access control typically implemented using access modifiers object class although access modifiers may syntactically different languages attempt achieve goal define variables methods visible several programming languages e.g java c++ c ruby use public protected private access modifiers keywords allow programmer establish access levels classes class members data methods exact use programming language varied depending language philosophy similarities differences note ruby private methods always self implicit receiver therefore used current object languages mechanisms override access modifies gain access private components object one example friend class c++ special public member methods accessors aka getters mutator methods often called setters used control changes class variables order prevent unauthorized access data corruption public policy access control restrict access systems authorization track monitor behavior within systems accountability implementation feature using trusted systems security social control
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Computer security
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4mlinux 4mlinux lightweight distribution made 32bit 64bit architectures named 4mlinux since 4 main components os maintenance used rescue live cd multimedia inbuilt support almost every multimedia format miniserver comes 64-bit server included running lamp suite mystery includes collection classic linux games distribution developed poland first released 2010 distribution include package manager uses jwm joe window manager default window manager also comes conky preinstalled installing programs distribution distribution retrieve windows version rather linux version due coming pre-installed wine compatibility layer windows applications package manager distribution geared towards people prefer lightweight distribution version distribution called 4mlinux game edition provides 90s games natively doom hexen distribution comes two different version 4mserver 4mlinux 4mlinux requires 128 mb ram installed hdd 1024 mb ram used live cd/usb whereas 4mserver requires 256 mb ram installed hdd 2048 mb ram used live cd/usb
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Operating systems
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nmap nmap network mapper free open-source network scanner created gordon lyon also known pseudonym fyodor vaskovich nmap used discover hosts services computer network sending packets analyzing responses nmap provides number features probing computer networks including host discovery service operating system detection features extensible scripts provide advanced service detection vulnerability detection features nmap adapt network conditions including latency congestion scan nmap started linux utility ported systems including windows macos bsd linux popular platform followed windows nmap features include nmap provide information targets including reverse dns names device types mac addresses typical uses nmap nmapfe originally written zach smith nmap official gui nmap versions 2.2 4.22 nmap 4.50 originally 4.22soc development series nmapfe replaced zenmap new official graphical user interface based umit developed adriano monteiro marques various web-based interfaces allow controlling nmap analysing nmap results web browser include nmap-cgi ivre microsoft windows specific guis exist including nmapwin updated since june 2003 v1.4.0 nmapw syhunt nmap provides four possible output formats interactive output saved file nmap output manipulated text processing software enabling user create customized reports nmap first published september 1997 article phrack magazine source-code included help contributions computer security community development continued enhancements included operating system fingerprinting service fingerprinting code rewrites c c++ additional scan types protocol support e.g ipv6 sctp new programs complement nmap core features major releases include nmap tool used discover services running internet connected systems like tool could potentially used black hat hacking precursor attempts gain unauthorized access computer systems however nmap also used security systems administration assess networks vulnerabilities i.e white hat hacking system administrators use nmap search unauthorized servers computers conform security standards jurisdictions unauthorized port scanning illegal nmap originally distributed gnu public license gpl later releases nmap authors added clarifications specific interpretations license felt gpl unclear lacking instance nmap 3.50 specifically revoked license sco group distribute nmap software views sco-linux controversies matrix reloaded trinity seen using nmap access power plant computer system allowing neo physically break building appearance nmap film widely discussed internet forums hailed unusually realistic example hacking nmap nmapfe used listening 2006 movie former nsa officer defects mounts clandestine counter-listening station high italian alps nmap source code seen movie battle royale well brief views command line version nmap executing live free die hard bourne ultimatum 2013 nmap continued make appearances movies including popular sci-fi movie elysium film dredd film adaptation famous judge dredd comics released 2012 also contains multiple nmap scenes nmap used network reconnaissance exploitation slum tower network even seen briefly movie trailer command nmap widely used video game hacknet allowing probe network ports target system hack snowden nmap used aptitude test scene 14 minutes movie nmap integral part academic activities used research involving tcp/ip protocol suite networking general well research tool nmap become research topic
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Computer security
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online complex processing online complex processing olcp class realtime data processing involving complex queries lengthy queries and/or simultaneous reads writes records
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Databases
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generic mapping tools generic mapping tools gmt open-source collection computer software tools processing displaying xy xyz datasets including rasterisation filtering image processing operations various kinds map projections software stores 2-d grids coards-compliant netcdf files comes comprehensive collection free gis data coast lines rivers political borders coordinates geographic objects users convert data like satellite imagery digital elevation models sources import gmt stores resulting maps diagrams postscript ps encapsulated postscript eps format users operate system command line enables scripting automation routine tasks less comprehensive graphic user interfaces available third parties well web applications bringing system functionality online paul wessel walter h. f. smith created gmt 1988 lamont-doherty earth observatory officially releasing october 7 1991 gnu general public license letters gmt originally stood gravity magnetism topography three basic types geophysical data besides strong support visualisation geographic data sets software includes tools processing manipulating multi-dimensional datasets gmt users geoscientists
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Databases
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macau computer emergency response team coordination centre macau computer emergency response team coordination centre mocert managed macau new technologies incubator centre providing macau computer security incident handling information promoting information security awareness well coordinating computer security incident response public local enterprises mocert collaborates local bodies also communicates exchange information members first forum incident response security teams apcert asia pacific computer emergency response teams mocert mission facilitate healthy secure internet environment macau mocert provides latest computer vulnerabilities discovered around world publishes latest security issues advisories website individuals organizations also register free mocert subscriber get latest related information email organization also provides advice best way handle computer incident free mocert accepts reports computer security related incidents example phishing malware malicious website phoney emails attachments information security attacks mocert organizes relevant seminars events macao constituency regular basis promote information security awareness macao public events topics altered according current issues facing macao mocert complements seminars events print material form leaflet booklets sections constituency requires awareness guidance information security
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Computer security
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road blaster laserdisc-based arcade games time gameplay consists on-screen instructions overlaid pre-recorded full motion video animated footage high-speed chases vehicular combat player controls cross-hair steer car toward correct directions according green arrows flashing beeping beside controlling gas pedal brake booster whenever light game nine stages upon successfully completing level player graded reaction time different difficulty levels selected normal mode pop-up icons audio tones signal turn left right brake hit turbo hit cars hard mode on-screen icons guide player story road blaster inspired revenge thriller films mad max takes place post-apocalyptic wasteland late 1990s united states future time game release player assumes role vigilante drives customized sports car order get revenge biker gang responsible wife death honeymoon recovering injuries upgrades car goes rampage nine areas goal seek gang female boss complete vengeance road blaster uses animation provided anime studio toei animation animated guidance yoshinobu inano also directed key-animated films animated using 15,000 hand-painted cels produce 30 minutes animation game director yoshihisa kishimoto previously worked cobra command later directed arcade version double dragon car road blaster seen inside lee brothers garage start game road blaster originally released 1985 laserdisc-based arcade game various ports released throughout including versions msx x1 mega cd/sega cd laseractive mega ld format sega saturn playstation 3do interactive multiplayer prototyped turbo blaster however sega cd mega ld versions released outside japan titles road avenger road prosecutor respectively titles possibly changed avoid confusion similarly titled arcade game roadblasters atari games ported mega drive around time road blaster also released sharp x68000 windows 2011 exclusively japan cobra command road blaster ported ios revolutionary concepts 2010 2011 respectively variations included one-shot reproductions vhs cassette players takara video challenger limited interactive port road blaster arcade game sega saturn playstation ports compilations road blaster another laserdisc arcade game developed team titled thunder storm known outside japan cobra command unofficial super nes port also released 2011 however game relies heavily msu1 media enhancement chip somewhat new chip allows 4gb additional storage space full motion video playback stereo pcm audio early 2018 another unofficial port released commodore amiga ocs aga versions released based mega cd version dragon reviewers gave sega cd version game 4 5 stars 1993 gamefan noted greater interaction compared time gal thunderstorm praised non-stop control vehicle graphics smooth animation andrenaline rush experience gamepro praised highly detailed animation stereo cd sound called masterpiece like participating intense action-packed animated movie release famitsu gave mega cd version score 32 40 mega rated 86 famitsu later scored sega saturn version 25 40 playstation version 23 40 ios port released generally favourable reviews including scores 8 10 ign 7 10 pocket gamer novelization game announced 2009 project officially authorized g-mode japan rights holder data east catalog written mary margaret park
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Computer architecture
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partition table partition fixed-size subset disk drive treated unit operating system partition table table maintained disk operating system describing partitions disk terms partition table partition map commonly associated mbr partition table master boot record mbr ibm pc compatibles may used generically refer formats divide disk drive partitions guid partition table gpt apple partition map apm bsd disklabel partitions created resized deleted called disk partitioning usually done installation operating system also possible make changes partitions operating system installed
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Computer file systems
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wait state wait state delay experienced computer processor accessing external memory another device slow respond computer microprocessors generally run much faster computer subsystems hold data cpu reads writes even memory fastest supply data fast cpu could process example 2011 typical pc processors like intel core 2 amd athlon 64 x2 run clock several ghz means one clock cycle less 1 nanosecond typically 0.3 ns 0.5 ns modern desktop cpus main memory latency 15–30 ns second-level cpu caches run slower processor core processor needs access external memory starts placing address requested information address bus must wait answer may come back tens hundreds cycles later cycles spent waiting called wait state wait states pure waste processor performance modern designs try eliminate hide using variety techniques cpu caches instruction pipelines instruction prefetch branch prediction simultaneous multithreading others single technique 100 successful together significantly reduce problem wait states used reduce energy consumption processor allowing main processor clock either slow temporarily pause wait state cpu work rather spinning uselessly tight loop waiting data sporadically reducing clock speed manner helps keep processor core cool extend battery life portable computing devices ibm mainframes term wait state used different meaning wait state refers cpu halted possibly due kind serious error condition unrecoverable error operating system ipl wait state indicated bit 14 psw set 1 bits psw providing wait state code giving reason wait z/architecture mode wait state code found bits 116-127
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Computer architecture
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advanced data communication control procedures telecommunication advanced data communication control procedures protocol adccp bit-oriented data link layer protocol used provide point-to-point point-to-multipoint transmission data frames contain error control information places data network ensures proper delivery destination adccp based ibm sdlc protocol hdlc iso lapb itu/ccitt based adccp adccp ansi standard x3.66 derived ibm synchronous data link control sdlc protocol functionally equivalent iso high-level data link control hdlc standard adccp 3 main modes – nrm normal response mode akin sdlc abm asynchronous balanced mode akin hdlc arm asynchronous response mode
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Internet protocols
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wietse venema wietse zweitze venema born 1951 dutch programmer physicist best known writing postfix email system also wrote tcp wrapper collaborated dan farmer produce computer security tools satan coroner toolkit studied physics university groningen continuing get phd 1984 dissertation left-right symmetry nuclear beta decay spent 12 years eindhoven university systems architect mathematics computer science department spent part time writing tools electronic data interchange since emigrating u.s. 1996 2015 working ibm thomas j. watson research center new york state march 24 2015 announced leaving ibm google awards venema received work
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Computer security
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ipswitch imail server imail handle many 300,000 users average message flow ~25 per second ~2 million day support 32 64 bit platforms iis/.net framework 2.0 smtp pop3 imap4 ldap protocol support rfc 1870 compliant business computing world review imail server premium v11.01 pc magazine voted imail server editor choice – march 2009 network computing awards 2008 messaging product year
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Internet protocols
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security maintenance security maintenance formerly known action center security center earlier versions component windows nt family operating systems monitors security maintenance status computer monitoring criteria includes optimal operation antivirus software personal firewall well working status backup restore network access protection nap user account control uac windows error reporting wer windows update notifies user problem monitored criteria antivirus program up-to-date offline security maintenance consists three major components control panel applet windows service application programming interface api provided windows management instrumentation wmi control panel applet divides monitored criteria categories color-codes yellow indicates non-critical warning e.g settings monitored optimal red indicates critical message e.g anti-virus program offline service named security center determines current state settings service default starts computer starts continually monitors system changes notifies user detects problem versions windows prior windows 10 adds notification icon windows taskbar wmi provider makes settings available system third-party anti-virus anti-spyware personal firewall software vendors primarily register security maintenance wmi provider windows vista added new set apis let programs retrieve aggregate health status within security maintenance receive notifications health status changes apis allow programs confirm system healthy state engaging certain actions example computer game ensure firewall running connecting online game security maintenance charge following microsoft learned discussions customers confusion whether users taking appropriate steps protect systems steps taking effective research microsoft made decision include visible control panel windows xp service pack 2 would provide consolidated view important security features service pack 2 released august 2004 includes first version windows security center wsc version monitors windows update windows firewall availability anti-virusprogram third-party providers personal firewall anti-virus software packages encouraged use wsc api register products wsc 25 august 2004 pc magazine published article security watch newsletter titled windows xp sp2 security center spoofing threat outlined design vulnerability could allow malware manipulate security center displaying false security status regardless true security status malware requires administrative privileges microsoft countered claim asserting piece malware gains administrative privileges need spoof anything commit much nastier malicious actions wsc windows vista monitors new criteria anti-spyware software user account control internet explorer security settings also display logos third-party products registered security center unlike windows xp beta versions windows vista wsc could disabled overridden security software maker symantec spoke noting would cause great deal consumer confusion security problems would reported wsc symantec tools time mcafee another large security software vendor lodged similar complaints end microsoft allowed wsc disabled windows 7 windows security center renamed action center designed centralize reduce number notifications system encompasses security maintenance computer notification icon windows taskbar appears message perusal replaces five separate notification icons found windows vista troubleshooting link also added providing shortcut windows 7 new troubleshooting control panel windows 8 action center monitors 10 new items microsoft account windows activation smartscreen automatic maintenance drive status device software startup apps homegroup file history storage spaces windows 10 name action center used application notifications quick actions action center windows 8.1 renamed security maintenance causing confusion users administrators longer displays icon notification area otherwise retains features windows 8.1 action center troubleshooting link removed windows 10 fall creators update starting windows 10 creators update microsoft introduced new component called windows defender security center wdsc provides much functionality new component universal windows platform app also default front-end windows defender relies service called windows defender security center service comparison security maintenance wdsc
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Operating systems
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economics security economics information security addresses economic aspects privacy computer security economics information security includes models strictly rational “ homo economicus ” well behavioral economics economics security addresses individual organizational decisions behaviors respect security privacy market decisions economics security addresses core question agents choose technical risks exists technical solutions mitigate security privacy risks economics addresses question also inform design decisions security engineering national security canonical public good economic status information security came intellectual fore around 2000 case innovations arose simultaneously multiple venues 2000 ross anderson wrote information security hard anderson explained significant difficulty optimal development security technology incentives must aligned technology enable rational adoption thus economic insights integrated technical design security technology enable party risk invest limit risk otherwise designers simply counting altruism adoption diffusion many consider publication birth economics security also 2000 harvard camp school government wolfram department economics argued security public good rather extant vulnerabilities associated negative externality value vulnerabilities defined work tradable goods six years later idefense zdi mozilla extant markets vulnerabilities 2000 scientists computer emergency response team carnegie mellon university proposed early mechanism risk assessment hierarchical holographic model provided first multi-faceted evaluation tool guide security investments using science risk since time cert developed suite systematic mechanism organizations use risk evaluations depending size expertise organization octave study computer security investment risk avoidance become standard practice 2001 unrelated development lawrence a. gordon martin p. loeb published using information security response competitor analysis systems working paper published article written 2000 professors maryland smith school business present game-theoretic framework demonstrates information security prevent rival firms gaining sensitive information context article considers economic i.e. cost-benefit aspects information security authors came together develop expand series flagship events name workshop economics information security proof work security technology designed stop spam altering economics early paper economics information security argued proof work work fact finding proof work work without price discrimination illustrated later paper proof work work another finding one critical understanding current american data practices opposite privacy economic terms anonymity rather price discrimination privacy price discrimination authored andrew odlyzko illustrates may appear information pathology collection data fact rational organizational behavior hal varian presented three models security using metaphor height walls around town show security normal good public good good externalities free riding end result case lawrence a. gordon martin p. loeb wrote economics information security investment gordon-loeb model considered many first economic model determines optimal amount invest protect given set information model takes account vulnerability information security breach potential loss breach occur
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Computer security
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tree-meta tree-meta tree meta treemeta translator writing system compiler-compiler system context-free languages originally developed 1960s parsing statements metalanguage resemble augmented backus–naur form embedded tree-building directives unparsing rules include extensive tree-scanning code-generation constructs tree-meta instrumental development on-line system ported many systems including univac 1108 ge 645 sds-940 icl 1906a perq ucsd p-system complete example tree-meta program extracted untested complete declarations conditionals blocks example appendix 6 icl 1900 tree-meta manual document also definition tree-meta tree-meta appendix 3 program recognizer also outputs assembly language input demonstrates one key features tree-meta tree pattern matching used lhs get val example rhs add sub algol-style comment delimited
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Programming language topics
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automatic repeat request automatic repeat request arq also known automatic repeat query error-control method data transmission uses acknowledgements messages sent receiver indicating correctly received packet timeouts specified periods time allowed elapse acknowledgment received achieve reliable data transmission unreliable service sender receive acknowledgment timeout usually re-transmits packet sender receives acknowledgment exceeds predefined number retransmissions types arq protocols include stop-and-wait arq go-back-n arq selective repeat arq/selective reject arq three protocols usually use form sliding window protocol tell transmitter determine packets need retransmitted protocols reside data link transport layers layers 2 4 osi model transmission control protocol uses variant go-back-n arq ensure reliable transmission data internet protocol provide guaranteed delivery packets selective acknowledgement sack uses selective repeat arq itu-t g.hn standard provides way create high-speed 1 gbit/s local area network using existing residential wiring power lines telephone lines coaxial cables uses selective repeat arq ensure reliable transmission noisy media arq systems widely used shortwave radio ensure reliable delivery data telegrams systems came forms called arq-e arq-m also included ability multiplex two four channels number patents exist use arq live video contribution environments high throughput environments negative acknowledgements used drive overheads
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Internet protocols
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