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zuora zuora enterprise software company creates provides software businesses launch manage subscription-based services zuora ’ applications designed automate recurring billing collections quoting revenue recognition subscription metrics tien tzuo founder company served ceo since 2007 2007 k.v rao cheng zou engineers webex tien tzuo early executive salesforce founded zuora name company derives combination three surnames concept behind company cloud-based billings platform alleviate need online businesses develop billing systems march 16 2018 company filed initial public offering april 12 2018 zuora listed nyse ticker symbol zuo company generated 154 million offering entered market public company 1.4 billion valuation end april 2018 company valued 2 billion 2016 zuora launched subscription economy index tracks revenue growth subscription businesses comparing growth sales benchmarks index based data hundreds businesses zuora platform index updated twice year zuora hosts conference series called subscribed covering topics related subscription economy taking place various cities year may 20 2015 zuora acquired frontleaf launched z-insights combining information subscriber invoicing billing platform customer usage information 2017 zuora purchased leeyo software revenue recognition platform december 17 2007 zuora announced raised 6 million series funding zuora announced 15 million series b funding september 15 2008 20 million series c funding october 2010 36 million series funding november 4 2011 50 million series e funding september 5 2013 115 million series f funding march 11 2015 bringing total funding 250 million investors include benchmark capital greylock partners redpoint ventures index ventures shasta ventures vulcan capital next world capital private investors include founder ceo salesforce marc benioff former peoplesoft vice-chair founder co-ceo workday dave duffield zuora sells subscription management saas platform businesses utilizing subscription-service model zuora central platform lets companies keep track subscription payments billing collections pricing product catalogs accounting addition zuora central zuora four primary saas applications zuora billing recurring billing operations zuora revpro revenue automation zuora cpq sales quoting subscription businesses zuora collect payment collections zuora app marketplace zuora connect allows partners develop list apps built zuora central platform june 5 2018 zuora announced subscription order management designed help customers process renewals complex deals addresses shift subscription growth related acquiring new customers growth existing customers
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Distributed computing architecture
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cardkey cardkey producer electronic access control products based simi valley california first company develop widely distribute electronic access control systems company original readers used cards made barium ferrite worked magnetically attracting repelling locking/unlocking cores within reader module mechanism cards primarily used fraternal organizations clubs bpoe elks others first develop wiegand cards readers magnetically based reliable require calibration used barium ferrite readers cards readers highly programmable used applications ranging adt american district telegraph government installations worldwide uk offices manchester reading sold systems companies british telecom shell bp main facility cardkey located nordhoff mason chatsworth additional location cozycroft chatsworth housed customer engineering singular engineering project pass system approximately 1978 division greer hydraulics inc. january 1999 bought johnson controls company whose founder invented electric room thermostat late 1800s
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Computer security
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robert j. chassell robert bob chassell one founding directors free software foundation fsf 1985 board directors chassell also treasurer fsf left fsf become full-time speaker free software topics bob born 22 august 1946 bennington vt diagnosed progressive supranuclear palsy psp 2010 died result 30 june 2017 chassell authored several books including
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Operating systems
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match day series match day association football video game franchise created jon ritman 1984 1980s 8-bit home computer market following games part match day series games published ocean exception super match soccer
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Computer architecture
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goff goff generalized object file format specification developed ibm zsystem mainframe computer supersede ibm os/360 object file format compensate weaknesses older format original ibm os/360 object file format developed 1964 new ibm system/360 mainframe computer format also used makers plug compatible workalike mainframes including univac 90/60 90/70 90/80 fujitsu b2800 format expanded add symbolic records expanded information modules plus support procedures functions names longer 8 characters helped provide enhanced information necessary today complicated programming languages advanced features objects properties methods unicode support virtual methods goff object file format developed ibm approximately 1995 means overcome problems note os/360 object file format simply superseded goff format deprecated still use assemblers language compilers language withstand limitations older format note article use term module refer name equivalent symbol used provide identifier piece code data external scope referenced module may refer subroutine function method property object class named routine identifier external particular scope referencing external name format similar os/360 object file format adds additional information use building applications similarly older os/360 format object file records divided 6 different record types added deleted altered goff records may fixed variable length minimum length using variable-length records 56 characters although records longer except module class names characters ebcdic character set unix-based systems must use fixed-length 80-byte records records fixed-length files shorter fixed length zero-filled distinguish goff records older os/360 format commands may present file first byte goff record always binary value x'03 commands must start character value least space x'40 next 2 bytes goff record indicate record type continuation version file format first 3 bytes known ptv field ptv field represents first 3 bytes every goff record hdr record required must first record esd record gives public name module main program subroutine procedure function property method object fortran common alternate entry point esd record public name must present file reference name made record case fixed-length records name requires continuation records following used adata associated data records used provide additional symbol information module replaced older sym records 360 object file format create adata record adata records appended end class order declared class names assigned adata records translated ibm programs converting binary value text appending name c_adata item numbered x'0033 would become text string c_adata0033 txt records specify machine code instructions data placed specific address location module note wherever length must specified record length value must include continuations record compression table used bytes 20-21 txt record nonzero r value used determine number times repeat string l value indicates length text repeated r times could used pre-initializing tables arrays blanks zero purpose useful express repeated data repeat count value note unlike number values stored goff file version release trans_date values numbers text characters instead binary normally compilers assemblers generate format record typically created binder text item character data binary information used rld records allow module show references address must relocated references specific locations external modules clarify module c program named basura issue call exit function terminate r_pointer address would esdid routine exit p_pointer would esdid basura len records used declare length module known time esd record created e.g one-pass compilers deferred-length element entry continued split end must last record module 'entry point used address beginning module used start point execution used either program non-executable data appearing start module common older assembly programmers older versions assembler much slower assemble data stored programs instructions specified module calls external module first run-time library initialize entry-point name specified fixed-length end record longer 54 bytes record also continued longer additional 80 bytes following continuation record used
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Operating systems
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alexander street press alexander street press asp electronic academic database publisher founded may 2000 alexandria virginia stephen rhind-tutt president janice cronin cfo eileen lawrence vice president sales marketing january 2016 company grown 100 employees offices united states australia brazil china united kingdom june 2016 acquired proquest company first product north american women letters diaries collection 150,000 pages letters diaries women colonial times 1950s 2000 collaboration artfl project university chicago company began using semantic indexing techniques humanities databases created metadata elements gender age sexual orientation characters within plays author nationality birthplace deathplace well item written elements combined full-text search allow material analyzed new ways 2003 company began major partnership center historical study women gender state university new york publish women social movements united states 1600–2000 subsequently become leading site study women history november 2004 alexander street acquired principal assets classical international london new york-based publisher streaming music libraries led new range music publications including partnership smithsonian institution provide smithsonian global sound libraries african american song november 2005 alexander street acquired range religious products produced ad fontes including digital library classic protestant texts digital library catholic reformation october 2006 company acquired assets university music editions small microfilm publisher specializing publication scores journals musically oriented publications collections subsequently released part classical scores library late 2006 company began developing online collections video theatre video published april 2007 followed succession online streaming video collections using techniques semantic indexing initially developed textual databases early provider synchronized scrolling transcripts allow watcher read ahead 2010 midsummer american library association company advertised 9 streaming video collections spanning 9,000 individual video titles april 2007 alexander street acquired principal products harpweek publisher harper weekly lincoln civil war june 2009 alexander street press arcadia publishing launched research website college local history information around united states canada september 2010 alexander street acquired microtraining associates specialist producer distributor therapy counseling videos december 2010 company acquired filmakers library distributor issue based documentaries 2011 alexander street acquired documentary film distributor filmmakers library 2012 acquired principal assets asia pacific films november 2013 alexander street announced acquisition insight media new york-based vendor dvd streaming media bringing asp catalog 50,000 academic video titles one first largest independent surveys streaming video north american academic libraries deg farrelly arizona state university jane hutchison william paterson university alexander street emerged leading vendor used 60 sites insight media present 10 sites 2013 company launched series case study databases combine books audio video reports pamphlets primary sources first two engineering case studies online documented major accidents 20th century psychological experiments online documented seminal experiments humans 2015 company secured arrangement cbs publish episodes sixty minutes 1996 2014 also announced open access initiatives anthropology anthropology commons music open music library following june alexander street press acquired proquest renamed alexander street proquest company 2016 company principal products academic video online 50,000 academically oriented video titles music online collection 8.3 million tracks music together scores reference works 120 primary source collections offerings across curriculum 60,000 video titles materials made available using wide range business models including demand driven access-to-own eba pda subscriptions perpetual licenses
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Databases
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ip flow information export internet protocol flow information export ipfix ietf protocol well name ietf working group defining protocol created based need common universal standard export internet protocol flow information routers probes devices used mediation systems accounting/billing systems network management systems facilitate services measurement accounting billing ipfix standard defines ip flow information formatted transferred exporter collector previously many data network operators relying cisco systems proprietary netflow technology traffic flow information export ipfix standards requirements outlined original rfc 3917 cisco netflow version 9 basis ipfix basic specifications ipfix documented rfc 7011 rfc 7015 rfc 5103 following figure shows typical architecture information flow ipfix architecture pool metering processes collects data packets one observation points optionally filters aggregates information packets exporter gathers observation points together observation domain sends information via ipfix protocol collector exporters collectors many-to-many relationship one exporter send data many collectors one collector receive data many exporters similar netflow protocol ipfix considers flowưởuoz number packets observed specific timeslot sharing number properties e.g source destination protocol using ipfix devices like routers inform central monitoring station view potentially larger network ipfix push protocol i.e sender periodically send ipfix messages configured receivers without interaction receiver actual makeup data ipfix messages great extent sender ipfix introduces makeup messages receiver help special templates sender also free use user-defined data types messages protocol freely extensible adapt different scenarios ipfix prefers stream control transmission protocol sctp transport layer protocol also allows use transmission control protocol tcp user datagram protocol udp simple information set sent via ipfix might look like information set would sent following ipfix message seen message contains ipfix header two ipfix sets one template set introduces build-up data set used well one data set contains actual data ipfix sent protocol keeps session state tcp sctp template set need retransmitted since buffered collectors since template set change time must retransmitted new session state established ipfix sent udp session-less protocol
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Internet protocols
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leveldb leveldb open-source on-disk key-value store written google fellows jeffrey dean sanjay ghemawat inspired bigtable leveldb hosted github new bsd license ported variety unix-based systems macos windows android leveldb stores keys values arbitrary byte arrays data sorted key supports batching writes forward backward iteration compression data via google snappy compression library leveldb sql database like nosql dbm stores relational data model support sql queries also support indexes applications use leveldb library provide server command-line interface mariadb 10.0 comes storage engine allows users query leveldb tables mariadb leveldb based concepts google bigtable database system table implementation bigtable system developed starting 2004 based different google internal code base leveldb code code base relies number google code libraries open sourced directly open sourcing code would difficult jeff dean sanjay ghemawat wanted create system resembling bigtable tablet stack minimal dependencies would suitable open sourcing also would suitable use chrome indexeddb implementation wrote leveldb starting early 2011 general design bigtable tablet stack sharing code leveldb used backend database google chrome indexeddb one supported backends riak additionally bitcoin core go-ethereum stores blockchain metadata using leveldb database minecraft pocket edition uses modified version chunk entity data storage autodesk autocad 2016 also uses leveldb google provided benchmarks comparing leveldb performance sqlite kyoto cabinet different scenarios leveldb outperforms sqlite kyoto cabinet write operations sequential-order read operations leveldb also excels batch writes slower sqlite dealing large values currently published benchmarks updated sqlite configuration mistakes noted earlier version results updated benchmarks show leveldb also outperforms berkeley db tests also show openldap lightningdb much faster ~10 times scenarios read operations write types e.g batch synchronous writes see link almost equal rest test leveldb history database corruption bugs study 2014 found older file systems database could become corrupted crash power failure
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Databases
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secure transmission computer science secure transmission refers transfer data confidential proprietary information secure channel many secure transmission methods require type encryption common email encryption called pki order open encrypted file exchange keys done many infrastructures banks rely secure transmission protocols prevent catastrophic breach security secure transmissions put place prevent attacks arp spoofing general data loss software hardware implementations attempt detect prevent unauthorized transmission information computer systems organization outside may referred information leak detection prevention ildp information leak prevention ilp content monitoring filtering cmf extrusion prevention systems used connection methods ensure secure transmission data wep deprecated algorithm secure ieee 802.11 wireless networks wireless networks broadcast messages using radio susceptible eavesdropping wired networks introduced 1999 wep intended provide confidentiality comparable traditional wired network later system called wi-fi protected access wpa since developed provide stronger security transport layer security tls predecessor secure sockets layer ssl cryptographic protocols provide secure communications internet things web browsing e-mail internet faxing instant messaging data transfers slight differences ssl tls substantially
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Computer security
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time sharing option time sharing option tso interactive time-sharing environment ibm mainframe operating systems including os/360 mvt os/vs2 svs mvs os/390 z/os time-sharing means many people access operating system concurrently unaware others also accessing operating system appears tso user user system tso commonly used mainframe system administrators programmers provides tso interacts users either line-by-line mode full screen menu-driven mode line-by-line mode user enters commands typing keyboard turn system interprets commands displays responses terminal screen mainframe interaction actually via ispf allows customized menu-driven interaction combination called tso/ispf tso also provide unix-style environment os/390 z/os via unix system services command shell without ispf tso commands embedded rexx execs clists run interactively batch tso eliminated need punch cards keypunch machine send card decks computer room read card reading machine originally introduced 1971 ibm considered time-sharing optional feature compared standard batch processing hence offered tso option os/360 mvt introduction mvs 1974 ibm made standard component top-end mainframe operating system tso/e time sharing option/extensions set extensions original tso tso/e base element z/os z/os tso extensions tso/e element os/390 licensed program mvs mvs/esa system products since z/os installations usually tso tso/e functions installed normal refer tso tso/e tso first released tso module names always prefix ikj plus second third letters associated pre-tso functional group iea original functional group supervisor hence tso module name ikjeaxxx ieb original functional group dataset utilities hence tso module name ikjebxxx etc. common run tso batch opposed interactively usual tso line-mode interactive commands also executed via job control language jcl running programs codice_1 codice_2 codice_3 supplying line commands file pointed codice_4 primary difference three programs handling return codes executed commands batch execution tso one way allow ibm mainframe application access db2 resources
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Operating systems
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fireeye fireeye publicly traded cybersecurity company headquartered milpitas california provides hardware software services investigate cybersecurity attacks protect malicious software analyze security risks fireeye founded 2004 initially focused developing virtual machines would download test internet traffic transferring corporate government network company diversified time part acquisitions 2014 acquired mandiant provides incident response services following identification security breach fireeye went public 2013 usatoday says fireeye called investigate high-profile attacks target jp morgan chase sony pictures anthem others yahoo finance says fireeye fastest-growing cyber security firm according deloitte fireeye founded 2004 ashar aziz former sun microsystems engineer received early investment cia investment arm in-q-tel 2009 fireeye first commercial product developed sold 2010 year fireeye expanded middle-east followed opening new offices asia pacific 2010 europe 2011 africa 2013 december 2012 founder aziz stepped ceo former mcafee ceo david dewalt appointed position dewalt recruited order prepare company initial public offering ipo following year fireeye raised additional 50 million venture capital bringing total funding 85 million late 2013 fireeye went public raising 300 million time fireeye growing rapidly 175 employees 2011 grew 900 june 2012 revenues multiplied eight-fold 2010 2012 however fireeye yet profitable due high operating costs research development expenses january 2014 fireeye acquired mandiant 1 billion mandiant private company founded 2004 kevin mandia provided incident response services event data security breach mandiant known investigating high-profile hacking groups acquisition fireeye would often identify security breach partner mandiant investigate hackers mandiant became subsidiary fireeye late 2014 fireeye initiated secondary offering selling another 1.1 billion shares order fund development wider range products shortly afterward fireeye acquired another data breach investigation company npulse approximately 60 million 2015 fireeye making 100 million annual revenue still unprofitable largely due research development spending january 2016 fireeye acquired isight partners 275 million isight threat intelligence company gathered information hacker groups cybersecurity risks followed acquisition invotas security automation company dewalt stepped ceo 2016 replaced mandiant ceo former fireeye president kevin mandia afterwards downsizing restructuring response lower-than-expected sales resulting layoff 300-400 employees afterwards profit revenue increased account shifts subscription model lower costs fireeye started sandboxing company sandboxing incoming network traffic opened within virtual machine test malicious software introduced network fireeye products diversified time part acquisitions 2017 fireeye transitioned primarily selling appliances software-as-a-service model fireeye sells technology products including network email endpoint security platform managing security operations centers called helix consulting services primarily based incident response threat intelligence products central management system cms consolidates management reporting data sharing web mps malware protection system email mps file mps malware analysis system mas single network-based appliance acting distribution hub malware security intelligence fireeye cloud crowd-sources dynamic threat intelligence dti detected individual fireeye mps appliances automatically distributes time sensitive zero-day intelligence globally subscribed customers frequent updates content updates include combination dti fireeye labs generated intelligence identified research efforts fireeye known uncovering high-profile hacking groups october/november 2009 fireeye participated effort take mega-d botnet also known ozdok march 16 2011 rustock botnet taken action microsoft us federal law enforcement agents fireeye university washington july 2012 fireeye involved analysis grum botnet command control servers located netherlands panama russia 2013 mandiant acquired fireeye uncovered multi-year espionage effort chinese hacking group called apt1 2014 fireeye labs team identified two new zero-day vulnerabilities – cve-2014-4148 cve-2014-4113 – part limited targeted attacks major corporations zero-days exploit windows kernel microsoft addressed vulnerabilities october 2014 security bulletin also 2014 fireeye provided information threat group calls fin4 fin4 appears conduct intrusions focused single objective obtaining access insider information capable making breaking stock prices public companies group targeted hundreds companies specifically targets emails c-level executives legal counsel regulatory risk compliance personnel individuals would regularly discuss confidential market-moving information also 2014 fireeye released report focused threat group refers apt28 apt28 focuses collecting intelligence would useful government specifically fireeye found since least 2007 apt28 targeting privileged information related governments militaries security organizations would likely benefit russian government 2015 fireeye confirmed existence least 14 router implants spread across four different countries ukraine philippines mexico india referred synful knock implant stealthy modification router ’ firmware image used maintain persistence within victim ’ network september 2015 fireeye obtained injunction security researcher attempting report vulnerabilities fireeye malware protection system 2015 fireeye uncovered attack exploiting two previously unknown vulnerabilities one microsoft office cve-2015-2545 another windows cve-2015-2546 attackers hid exploit within microsoft word document .docx appeared résumé combination two exploits grant fully privileged remote code execution vulnerabilities patched microsoft 2015 fireeye service team singapore uncovered phishing campaign exploiting adobe flash player zero-day vulnerability cve-2015-3113 adobe released patch vulnerability out-of-band security bulletin fireeye attributed activity china-based threat group tracks apt3 2016 fireeye announced tracking pair cybercriminals referred “ vendetta brothers. ” company said enterprising duo uses various strategies compromise point-of-sale systems steal payment card information sell underground marketplace “ vendetta world. ” mid-2016 fireeye released report impact 2015 agreement former u.s. president barack obama chinese president xi jinping neither government would “ conduct knowingly support cyber-enabled theft intellectual property ” economic advantage security firm reviewed activity 72 groups suspects operating china otherwise support chinese state interests determined mid-2014 overall decrease successful network compromises china-based groups organizations u.s. 25 countries 2016 fireeye announced identified several versions ics-focused malware – dubbed irongate – crafted manipulate specific industrial process running within simulated siemens control system environment although siemens product computer emergency readiness team productcert confirmed fireeye irongate viable operational siemens control systems irongate exploit vulnerabilities siemens products security firm said irongate invokes ics attack concepts first seen stuxnet may 8 2016 fireeye detected attack exploiting previously unknown vulnerability adobe flash player cve-2016-4117 security firm reported issue adobe product security incident response team psirt adobe released patch vulnerability four days later 2016 fireeye discovered widespread vulnerability affecting android devices permits local privilege escalation built-in user “ radio ” making attacker potentially perform activities viewing victim ’ sms database phone history fireeye reached qualcomm january 2016 subsequently worked qualcomm product security team address issue 2016 fireeye provided details fin6 cyber criminal group steals payment card data monetization targets predominately hospitality retail sectors group observed aggressively targeting compromising point-of-sale pos systems making millions payment card numbers later sold underground marketplace fireeye firm mandiant hired russia alfa bank locate information connections u.s. president donald trump servers also hired equifax determine source data breach cases mandiant find anything conclusive 2017 fireeye detected malicious microsoft office rtf documents leveraging previously undisclosed vulnerability cve-2017-0199 vulnerability allows malicious actor download execute visual basic script containing powershell commands user opens document containing embedded exploit fireeye shared details vulnerability microsoft coordinated public disclosure timed release patch microsoft address vulnerability 2018 fireeye helped facebook identify 652 fake accounts
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Computer security
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objvlisp objvlisp 1984 object-oriented extension vlisp–vincennes lisp lisp dialect developed since 1971 university paris viii – vincennes noteworthy one earliest implementations concept metaclasses particular explicit opposed implicit metaclasses objvlisp model entity instance single class classes instances classes called metaclasses model allows extension static part ool i.e structural aspects objects considered implementation abstract data types objvlisp provided far flexible metaclass model provided earlier object-oriented languages especially smalltalk smalltalk-80 whenever new class created corresponding metaclass created automatically name independent metaclass created–metaclasses implicit rather explicit contrast objvlisp possible define named metaclasses defining class one must specify named metaclass instantiate explicit metaclass support objvlisp influenced provision capability common lisp object system objvlisp object model later implemented prolog produce objvprolog python converge implement meta-class system equivalent objvlisp
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Programming language topics
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common filesystem features glossary common filesystem features table intention table provide at-a-glance list features specifications filesystem list names credited design filesystem specification include responsible writing implementation full non abbreviated name filesystem name operating system filesystem debuted partitioning scheme marker used identify partition formatted filesystem describe filesystem allocates isolates bad sectors describes filesystem allocates sectors in-use files describes subdirectories implemented lists characters legal within file directory names maximum number characters file directory name may contain maximum number files filesystem handle maximum size volume filesystem specification handle may differ maximum size operating system supports using given implementation filesystem type dates times filesystem support may include date file “ created ” volume change working normally file e.g opening closing saving modifying file date file last accessed access move open simple access also tripped anti-virus scanners windows system processes therefore caution used stating “ file last accessed user xxx ” “ file access ” date ntfs work date shown windows change file e.g notepad document data added would trip date modified date time related attributes modified may include acls file/directory name date time file last backed maximum year handled filesystem per specification lists basic file attributes available determines filesystems supports multiple data streams ntfs refers alternate data streams hpfs extended attributes hfs calls forks filesystem support real-time transparent compression decompression entire volume filesystem support real-time transparent encryption decryption entire volume filesystem support real-time transparent compression decompression individual files filesystem support real-time transparent encryption decryption individual files filesystem support multi-user access control lists acls
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Computer file systems
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timestamping computing computing timestamping refers use electronic timestamp provide temporal order among set events timestamping techniques used variety computing fields network management computer security concurrency control instance heartbeat network uses timestamping monitor nodes high availability computer cluster timestamping computer files updating timestamp per-file metadata every time file modified makes possible use efficient build automation tools
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Computer security
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jruby jruby implementation ruby programming language atop java virtual machine written largely java free software released three-way epl/gpl/lgpl license jruby tightly integrated java allow embedding interpreter java application full two-way access java ruby code similar jython python language jruby lead developers charles oliver nutter thomas enebo many current past contributors including ola bini nick sieger september 2006 sun microsystems hired enebo nutter work jruby full-time june 2007 thoughtworks hired ola bini work ruby jruby july 2009 jruby developers left sun continue jruby development engine yard may 2012 nutter enebo left engine yard work jruby red hat jruby originally created jan arne petersen 2001 time several years following code direct port ruby 1.6 c code release ruby 1.8.6 effort began update jruby 1.8.6 features semantics since 2001 several contributors assisted project leading current core team around six members jruby 1.1 added just-in-time compilation ahead-of-time compilation modes jruby already faster cases then-current ruby 1.8.7 reference implementation jruby packages available platforms fedora 9 among first include standard package jruby 1.1.1 july 2009 core jruby developers sun microsystems charles oliver nutter thomas enebo nick sieger joined engine yard continue jruby development may 2012 nutter enebo left engine yard work jruby red hat jruby supported compatibility ruby mri versions 1.6 1.9.3 jruby 1.0 supported ruby 1.8.6 jruby 1.4.0 updating compatibility ruby 1.8.7 jruby 1.6.0 added simultaneous support ruby 1.9.2 jruby 1.7.0 making ruby 1.9.3 default execution mode ruby 1.8.7 compatibility available via command-line flag jruby 9.0.0.0 added support ruby 2.2 jruby able run ruby rails web framework since version 0.9 may 2006 ability execute rubygems webrick since hiring two lead developers sun rails compatibility speed improved greatly jruby version 1.0 successfully passed nearly rails test cases since developers begun use jruby rails applications production environments february 27 2008 sun microsystems university tokyo announced joint-research project implement virtual machine capable executing one ruby jruby application one interpreter jsr 292 supporting dynamically typed languages javatm platform proposes sun open source project multi language virtual machine aims prototype jsr first working prototype developed patch openjdk announced made available end august 2008 jruby team implemented dynamic invocation codebase dynamic invocation initially shipped 1.1.5 release primitive form version 1.7.0 enabled default java 8 builds table presents releases present significant steps jruby history aside versions mainly fixed bugs improved performance performance improvements also shown table every release usually brought improvements since early 2006 current jruby core team endeavored move jruby beyond simple c port support better performance aid eventual compilation java bytecode support end team set ambitious goal able run ruby rails unmodified using jruby process achieving goal jruby test suite expanded extent team gained confidence correctness jruby result toward end 2006 beginning 2007 began commit much complicated redesigns refactorings jruby core subsystems jruby designed work mixed-mode virtual machine ruby code either interpreted directly just-in-time compiled runtime java bytecode ahead-of-time compiled java bytecode execution october 2007 interpreted mode supported ruby constructs full aot/jit compiler available since version 1.1 compiler design allows interpreted compiled code run side-by-side well decompilation reoptimize outputting generated bytecode java class files jruby built-in support rails rspec rake rubygems embeds ffi subsystem allow use c libraries bundled gems also allows launching interactive ruby shell irb ruby mri netbeans ruby pack available netbeans 6 allows ide development ruby jruby well ruby rails two implementations ruby longer included netbeans 7.0 later jruby similar standard ruby interpreter except written java jruby features concepts including object-oriented programming dynamic-typing ruby key difference jruby tightly integrated java called directly java programs java significant footing development web applications one powerful feature jruby ability invoke classes java platform one must first load jruby java support calling require 'java following example creates java jframe jlabel jruby also allows user call java code using ruby-like underscore method naming refer javabean properties attributes jruby easily called java using either jsr 223 scripting java 6 apache bean scripting framework according benchmarks jruby faster alternatives since implementations vary much code loaded execution different methods measuring speed lead biased interpretations performance advantages time takes java virtual machine load often excluded execution times calculating benchmarks jruby significant architectural advantage able leverage jvm threads without constrained global interpreter lock similarly rubinius therefore achieving full parallelism within process ruby mri achieve despite leveraging os threads real mongrel web server application tested 2007 jruby performance better ruby mri 1.8 java virtual machine instantiated 2007 benchmark ruby implementations jruby faster ruby mri 1.8 tests yarv outperformed april 2014 computer language benchmarks game jruby 1.7.4 typically performance ruby mri 2.1.0 uses memory
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Programming language topics
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ticket granting ticket computer security systems ticket granting ticket ticket get tickets tgt small encrypted identification file limited validity period authentication file granted user data traffic protection key distribution center kdc subsystem authentication services kerberos tgt file contains session key expiration date user ip address protects user man-in-the-middle attacks tgt used obtain service ticket ticket granting service tgs user granted access network services service ticket provided
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Computer security
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le lisp le lisp also le_lisp le-lisp programming language dialect language lisp developed french institute research computer science automation inria implementation language large scale integration vlsi workstation designed direction jean vuillemin le lisp also run various incompatible platforms mostly running unix operating systems used project main goals language powerful post-maclisp version lisp would portable compatible extensible efficient jérôme chailloux led le lisp team working emmanuel st. james matthieu devin jean-marie hullot 1980 dialect historically noteworthy one first lisp implementations available apple ii ibm pc
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Programming language topics
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prose modeling language prose mathematical 4gl virtual machine established holistic modeling paradigm known synthetic calculus aka metacalculus successor slang/cue simulation optimization language developed trw systems introduced 1974 control data supercomputers first commercial language employ automatic differentiation ad optimized loop instruction-stack cdc 6600 cpu although prose rich block-structured procedural language focus blending simultaneous-variable mathematical systems kinds system models distinct operator templates automate solve added procedural syntax automated system problems considered holistic unknowns simultaneous could reduced formulation solve piecewise algebra manipulation e.g substitution solved wholes wholeness also pertained algorithmic determinacy mathematical closure made solution convergence possible certain principle corrupted numerical instability since holistic problem models could independently automated solved due closure could blended higher wholes nesting one inside another manner subroutines users could regard ordinary subroutines yet semantically mathematical blending considerably complex mechanics subroutines iterative solution engine attached problem model calling operator template program hierarchy numerical solution process engine would take control would call problem model subroutine iteratively returning calling template system problem solved maybe iterative model-subroutine calls engine would invoke automatic differentiation formulas model holarchy respect model input-unknowns arguments defined calling template additional mechanisms performed semantics accommodate ubiquitous nesting holistic models nested solution prediction e.g numerical integration solution algorithm addition model formulas would also automatically differentiated since differentiation propagated via chain rule throughout integration initial conditions boundary conditions differentiation boundary conditions respect initial conditions called fréchet derivatives would performed enabled routine solution boundary-value problems iterative shooting methods using newton-method engines course time propagated differentiation could also performed respect arbitrary parameters differential equations shape integrated functions parameters could solved unknowns nest holarchy integration process significant convenience overall problem formulation inner nested problem search outer problem also search e.g optimization partial derivatives produced respect inner-search unknowns converted partial derivatives outer search via differential-geometry coordinate transformation also iterative process involving higher order differentiation sometimes different independent variables yet extended iterative differential-arithmetic processes totally hidden user hardly significant modeling task ordinary subroutines calls involved fact iterative number kind iterations indefinite whole sub-problem solved also part higher problem natural call problem nest holon dynamic entity perfectly fitted theory arthur koestler coined term done original prose documentation years koestler theory new somewhat controversial term later used ken wilber ratified koestler holon concepts complete modeling paradigm consisted three classes holons distinguished operator templates three operator templates created dynamic holons encapsulating equations model subroutine hierarchy could contain nested holons model subroutines could contain operator templates encapsulating sub-problems holon holarchy solver algorithm engine could interchanged others holon class extended arithmetic automatic differentiation ability dynamically differentiate numerical integration gave rise unique mode holarchy modeling illustrated figure 1 example problem originally fortran application rand report algorithm used optimization boundary-value problem applications report also published textbook described quasilinearization alternative dynamic programming invented author richard bellman fortran program appendix two textbook contains five times amount code 25-line prose program entirely embedded white boxes visible syntax figure 1 significant modeling versus programming discussion fortran program contains 14 loops whereas prose program contains loops another point make program simplification dynamic memory management could taken granted user return holon calling operator template holon destroyed memory freed use application actually trivial amount code required state problem prose program small iterative solution methodology hood solver engines ellipses figure 1 models seldom need loops spreadsheets modeling tools n't even example problem provides full encapsulation holon paradigm single application three holon types employed optimization searching highest level holarchy correlation searching restricted subset optimization searching middle holon system dynamics simulation innermost holon another prose program anatomy illustrated figure 2 somewhat larger application optimization cantilevered wing structure maximize lift subject structure weight constraints case ten coordinate dimensions optimization unknowns searched outer holon solver two outer holons hidden coordinate system unknowns search engine solves engines require partial derivatives downstream variables dependent upon unknowns evaluated automatic differentiation arithmetic derivatives outer coordinate system must computed derivatives inner coordinate system inner search engine converged found local solution differential-geometry coordinate transformation applied wing problem figure 2 downstream subprograms shown including integral quadrature function subprograms include numerical integration system dynamics differential equations model automatic differentiation arithmetic includes differentiation integration algorithm simulation engine quadrature solver evaluate derivatives boundary end-point integrated curves conditions respect initial conditions calculation possible via formal symbolic differentiation feasible finite difference approximation automatic differentiation exact chain-rule propagation feasible figure 3 shows generalized architecture holon profile showing visible modeling syntax invisible semantics architecture characteristic 5-step iteration process holon calculus problem-solving unit mathematically associated coordinate system dynamically created operation template operator solver engine either numerical predictor case simulation search engine case correlation optimization operand model procedure may holarchy subordinated holons essence holon metaphoric computation container like spreadsheet allowing procedural looping like ordinary algebraic language yet purpose frame algebraic formulas represent higher mathematics e.g differential equations algebraic formulas variables rates figures 4-7 show different holon classes simulation correlation optimization reflect architecture separating modeling science equations algorithmic solver engines art numerical approximation mathematics mentioned holon computation container like spreadsheet encapsulates set input algebraic formulas unlike spreadsheet formulas parts irreducible whole solved together unit involving succession approximations iterations spreadsheet involves single pass formula calculations may therefore thought degenerate reduced holon one involves single-pass calculations holon model elevates encapsulated system algebraic formulas higher problem archetype relating simultaneous unknowns definable solution condition single pass set formulas iterative calculus hood required converge multiple-pass approximations solution condition holon automates one three system-problem archetypes emerged higher math distinct class solution methods applicable interchangeable operators methods operate input formulas calculations guide successive approximations holon solution problem archetypes easily precipitate formula collections represent modeling natural phenomena used building blocks synthesize whole computation programs holarchies sequential nested holons used together alphabet archetypal problems become topology higher math modeling within algebraic programming language containing special semantic glue methodologies propagate calculus influence collections holons holons combine form greater wholes via alphabetic combination holarchies also tend become problem archetypes often precipitate natural phenomena modeling examples boundary-value problems solved combination correlation simulation holons prose introduced pantheon interchangeable solvers named mythical gods three engine categories solvers applied different numerical methods three engine categories depending upon nesting context applied simulation solvers janus mercury minerva merlin pegasus could nested automatic differentiation contexts correlation optimization overloaded automatic-differentiation arithmetic thus hybrid versions janisis isis janus gemini merlin neptune introduced would work efficiently automatic differentiation mode ordinary arithmetic mode differentiation internally turned greatly speeded iterative searches solvers like ajax mars jove zeus jupiter iteratively called models many times non-differentation mode various modes non-derivative search sub-steps applied
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Programming language topics
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hp autonomy hp autonomy previously autonomy corporation plc multinational enterprise software company founded cambridge united kingdom 1996 originally autonomy specialised analysis large scale unstructured big data becoming uk largest successful software business 2010 used combination technologies born research university cambridge developed variety enterprise search knowledge management applications using adaptive pattern recognition techniques centered bayesian inference conjunction traditional methods maintained aggressively entrepreneurial marketing approach controls described rod iron said include zero tolerance firing weakest 5 sales force quarter cosseting best sales staff like rock stars autonomy acquired hewlett-packard hp october 2011 deal valued autonomy 11.7 billion £7.4 billion premium around 79 market price widely criticized absurdly high botched strategy shift chaotic attempt rapidly reposition hp enhance earnings expanding high-margin software services sector within year major culture clashes became apparent hp written 8.8 billion autonomy value hp claims resulted accounting improprieties misrepresentations disclosure failures previous management successful fraud case brought cfo sushovan hussain previous management turn accused hp textbook example defensive stalling conceal evidence prior knowledge gross mismanagement undermining company noting public awareness since 2009 financial reporting issues even hp cfo disagreed price paid external observers generally state small part write-off appears due accounting mis-statements hp overpaid businesses previously hp recruited robert youngjohns ex-microsoft president north america take hp autonomy september 2012 worked towards turnaround expanding information management analytics software business though company integrating hp software autonomy remains singular operational business 2017 hp sold autonomy assets part wider deal british software company micro focus autonomy founded cambridge england michael lynch david tabizel richard gaunt 1996 spin-off cambridge neurodynamics firm specializing computer-based finger print recognition autonomy floated 1998 nasdaq exchange share price approximately £0.30 height dot-com bubble peak share price £30 december 2005 autonomy acquired verity inc. one main competitors approximately us 500 million 2005 autonomy also acquired neurodynamics may 2007 exercising option buy stake technology start blinkx inc combining consumer division autonomy floated blinkx valuation 250 million july 2007 autonomy acquired zantaz email archiving litigation support company 375 million october 2007 autonomy acquired meridio holdings ltd uk company based northern ireland specialised records management software £20 million 28 may 2008 kainos extended partnership autonomy high-end information processing information risk management irm deliver information governance solutions customer base january 2009 autonomy acquired interwoven niche provider enterprise content management software 775 million interwoven became autonomy interwoven autonomy imanage 2009 paul morland leading analyst started raising concerns autonomy exaggerated performance claims june 2010 autonomy announced acquire information governance business ca technologies terms sale disclosed 5 may 2011 mercedes formula one team announced 8 million sponsorship deal autonomy 8 july 2010 tottenham hotspur fc announced two-year sponsorship deal autonomy premier league kit 2011–12 season spurs premier league shirt featured autonomy augmented reality technology aurasma 16 may 2011 autonomy acquired iron mountain digital pioneer e-discovery online backup solutions provider 380 million iron mountain incorporated 18 august 2011 hewlett-packard announced would purchase autonomy us 42.11 per share transaction unanimously approved boards directors hp autonomy autonomy board recommended shareholders accept offer 3 october 2011 hp closed deal announcing acquired around 87.3 shares around 10.2 billion valuing company around 11.7 billion total may 2012 mike lynch left role autonomy ceo significant drop revenue previous quarter september 2012 robert youngjohns appointed svp gm autonomy/information management business unit november 2012 hewlett-packard announced taking 8.8 billion accounting charge claiming serious accounting improprieties outright misrepresentations autonomy share price fell decades low news however mike lynch counter-alleged problems due hp running autonomy citing internecine warfare within organization serious fraud office united kingdom u.s. securities exchange commission joined fbi investigating potential anomalies however january 2015 sfo closed investigation chance successful prosecution low three lawsuits brought shareholders hp fall value hp shares august 2014 united states district court judge threw proposed settlement autonomy previous management argued would collusive intended divert scrutiny hp executives responsibility knowledge fee 48 million april 2018 autonomy ex-cfo sushovan hussain charged us found guilty accounting fraud evidence lynch charged fraud november 30 january 2014 company announced one partners kainos integrated hp idol 10.5 new version hp autonomy ’ information analytics engine kainos electronic medical record platform evolve 31 october 2015 autonomy software products divided hp inc hpq hewlett packard enterprise hpe result hewlett-packard co separation hp inc assigned ownership largely consisting autonomy content management software components including teamsite qfiniti qfiniti managed services mediabin optimost explore hewlett packard enterprise retains ownership remaining software 2 may 2016 opentext acquires hp teamsite hp mediabin hp qfiniti hp explore hp aurasma hp optimost hp inc 170 million 1 september 2017 merged micro focus hp autonomy products include intelligent data operating layer idol allows search processing text taken structured data unstructured human information—including e-mail mobile data—whether originates database audio video text files streams processing information idol referred autonomy meaning-based computing hp autonomy offerings include api platform building data rich applications ease use quick deploy enterprise search solution built onto ondemand api platform june 2013 hp announced platform analyzing finding meaning big data petabytes structured unstructured information also aims identify information needed placed low cost storage even dumped components platform include january 2014 hp released new version hp idol strengthens integration several key components platform expanding upon idol ’ analytics reliability ease use cmswire reported new release lot hood catapult idol firmly center big data fray autonomy business primary offices cambridge sunnyvale california well major offices uk us canada france japan australia singapore germany smaller offices india throughout europe latin america
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Distributed computing architecture
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reverse telnet reverse telnet specialized application telnet server side connection reads writes data computer terminal line rs-232 serial port rather providing command shell host device typically reverse telnet implemented embedded device e.g terminal/console server ethernet network interface serial port use reverse telnet device ip-networked users use telnet access serially-connected devices past reverse telnet typically used connect modems external asynchronous devices today reverse telnet used mostly connecting console port router switch device client command line initiating reverse telnet connection might look like telnet 172.16.1.254 2002 example 172.16.1.254 ip address console device 2002 tcp port associated terminal line server
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Internet protocols
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attribute-based access control attribute-based access control abac also known policy-based access control defines access control paradigm whereby access rights granted users use policies combine attributes together policies use type attributes user attributes resource attributes object environment attributes etc. model supports boolean logic rules contain statements making request resource action example requestor manager allow read/write access sensitive data unlike role-based access control rbac employs pre-defined roles carry specific set privileges associated subjects assigned key difference abac concept policies express complex boolean rule set evaluate many different attributes attribute values set-valued atomic-valued set-valued attributes contain one atomic value examples role project atomic-valued attributes contain one atomic value examples clearance sensitivity attributes compared static values one another thus enabling relation-based access control although concept existed many years abac considered next generation authorization model provides dynamic context-aware risk-intelligent access control resources allowing access control policies include specific attributes many different information systems defined resolve authorization achieve efficient regulatory compliance allowing enterprises flexibility implementations based existing infrastructures attribute-based access control sometimes referred policy-based access control pbac claims-based access control cbac microsoft-specific term key standards implement abac xacml alfa xacml abac seen abac comes recommended architecture follows attributes anything anyone tend fall 4 different categories functions grammatical function policies statements bring together attributes express happen allowed policies abac granting denying policies policies also local global written way override policies examples include abac many policies like cater many different scenarios technologies historically access control models included mandatory access control mac discretionary access control dac recently role-based access control rbac access control models user-centric take account additional parameters resource information relationship user requesting entity resource dynamic information e.g time day user ip abac tries address defining access control based attributes describe requesting entity user targeted object resource desired action view edit delete ... environmental contextual information access control said attribute-based one standard implements attribute- policy-based access control xacml extensible access control markup language xacml defines architecture policy language request response scheme handle attribute management user attribute assignment object attribute assignment environment attribute assignment left traditional iam tools databases directories companies including every branch united states military started using abac basic level abac uses ‘ if/then/and ’ model protect data rather assigning data user take information anywhere please give hacker ability swipe file us department commerce made mandatory practice adoption spreading throughout several governmental military agencies concept abac applied level technology stack enterprise infrastructure example abac used firewall server application database data layer use attributes bring additional context evaluate legitimacy request access inform decision grant deny access important consideration evaluating abac solutions understand potential overhead performance impact user experience expected granular controls higher overhead abac used apply attribute-based fine-grained authorization api methods functions instance banking api may expose approvetransaction transid method abac used secure call abac policy author write following flow would follows one key benefits abac authorization policies attributes defined technology neutral way means policies defined apis databases reused application space common applications benefit abac process flow one described api section applies security databases long specific database vendors oracle vpd ibm fgac microsoft rls means achieve fine-grained abac-like security using abac possible define policies apply across multiple databases called dynamic data masking example would data security typically goes one step database security applies control directly data element often referred data-centric security traditional relational databases abac policies control access data table column field cell sub-cell using logical controls filtering conditions masking based attributes attributes data user session tools based deliver greatest level flexibility dynamically granting/denying access specific data element big data distributed file systems hadoop abac applied data layer control access folder sub-folder file sub-file granular attribute-based access control also applied big data systems like hadoop policies similar used previously applied retrieving data data lakes windows server 2012 microsoft implemented abac approach controlling access files folders achieved dynamic access control lists dacl security descriptor definition language sddl sddl seen abac language uses metadata user claims file folder control access gartner improving-runtime-authorization-maturity
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Computer security
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dorothy blum dorothy toplitzky blum february 21 1924 – october 1980 american computer scientist cryptanalyst worked national security agency predecessors 1944 death 1980 dorothy toplitzky born 1924 new york city austro-hungarian immigrant parents graduating brooklyn college 1944 joined cryptologic unit u.s. army remained organization world war ii became united states army security agency later national security agency nsa married nsa mathematician joseph blum 1950 later son 1950s blum worked nsa internal organization tasked keep ing abreast latest advances field computing recommended computer technologies could adapted cryptanalysis communications intelligence wrote computer software nsa spearheaded effort teach nsa employees write cryptanalytic programs began using fortran programming language three years public release 1957 throughout 1960s 1970s blum continued work field computer science helping design nsa computer systems automate processes 1972 became chief nsa computer operations organization c7 woman time organization management hierarchy appointed chief plans project development organization t4 telecommunications computer services organization 1977 also involved women nsa win group blum died cancer october 1980 aged 56 internal award nsa named 2004 inducted nsa hall honor official nsa biography states 36-year career blum significantly changed way nsa cryptanalysis also elected one top 100 outstanding women federal government
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Computer security
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security bsides security bsides commonly referred bsides series loosely affiliated information security conferences co-founded mike dahn jack daniel chris nickerson 2009 due overwhelming number presentation submissions black hat usa 2009 rejected presentations presented smaller group individuals time conference format matured released enable individuals start bsides conferences three event styles structured unconference hybrid structured event follows traditional conference model often times happens tandem larger conferences black hat rsa etc attendees typically intermingle attend one events talks submitted local event ahead time selected scheduled prior start conference unconference event style completely attendee driven attendees appear predetermined time discuss ideas collaboratively agree upon schedule look like day talks get attention conversation get added schedule
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Computer security
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h.248 gateway control protocol megaco h.248 implementation media gateway control protocol architecture providing telecommunication services across converged internetwork consisting traditional public switched telephone network pstn modern packet networks internet h.248 designation recommendations developed itu telecommunication standardization sector itu-t megaco contraction media gateway control protocol used earliest specifications internet engineering task force ietf standard published march 2013 itu-t entitled h.248.1 gateway control protocol version 3 megaco/h.248 follows guidelines published rfc 2805 april 2000 entitled media gateway control protocol architecture requirements protocol performs functions media gateway control protocol mgcp however formal standard mgcp informational status using different syntax symbolic representation two protocols directly interoperable complementary h.323 session initiation protocol sip protocols h.248 result collaboration megaco working group internet engineering task force ietf international telecommunication union telecommunication study group 16 ietf originally published standard rfc 3015 superseded rfc 3525 term megaco ietf designation megaco combines concepts mgcp media device control protocol mdcp mgcp originated combination simple gateway control protocol sgcp internet protocol device control ipdc itu took responsibility protocol maintenance ietf reclassified publications historic rfc 5125 itu published three versions h.248 recent september 2005 h.248 encompasses base protocol specification h.248.1 many extensions defined throughout h.248 sub-series h.248/megaco due master-slave nature describe establishment calls across domains across media gateway controllers h.248/megaco used communication downward media gateways constitute complete system architecture requires protocols communication multiple mgcs device handles call control function referred intelligent media gateway controller device handles media referred relatively unintelligent media gateway h.248 defines protocol media gateway controllers control media gateways support multimedia streams across ip networks public switched telephone network pstn typically used providing voice internet protocol voip services like voice fax ip networks pstn entirely within ip networks types devices targeted control h.248/megaco low level control structure h.248 generally viewed complementary h.323 session initiation protocol sip media gateway controller mgc uses h.248/megaco manage media establishment control number media gateways mgs voip protocols sip h.323 used one communication controllers sip perspective combination mgc mgs treated together sip gateway h.248/megaco model describes connection model contains logical entities objects within media gateways mgs controlled media gateway controller main entities contexts terminations ip multimedia subsystem ims media gateway control function mgcf control media gateways mgw send receive call pstn circuit switched cs networks using h.248 mgcf uses sip messages interact call session control function cscf breakout gateway control function bgcf although modeling media gateway differs h.248/megaco compared mgcp similarity semantics commands two specifications almost one-to-one mapping commands megaco mgcp example create connection command mgcp equivalent add termination command megaco modify connection command mgcp equates modify termination command megaco delete connection command equates subtract termination command megaco h.248/megaco model complex media gateway control protocol mgcp model provides flexibility defining media control example mgcp call use endpoint mode conference manage stream mixing achieve fine grain control h.248/megaco managing media streams h.248/megaco model simplifies connection setup within mg entities outside mg simplifies mechanism media gateway controller mgc specify associated media streams well specify direction media flow h.248/megaco therefore able provide greater application level support mgcp example setting multi-party conference h.248 merely involves adding several terminations context case mgcp however mgc needs establish several connections special type endpoint called conference bridge following main differences megaco/h.248 mgcp
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Internet protocols
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sqrrl sqrrl data inc. american company founded 2012 markets software big data analytics cyber security company roots united states intelligence community national security agency sqrrl involved creation actively contributes apache accumulo related apache projects sqrrl ’ primary product threat hunting platform designed active detection advanced persistent threats january 2018 sqrrl acquired amazon sqrrl ’ founders previously worked national security agency ceo co-founder oren falkowitz formerly cybercommand co-founder ely kahn former director us cybersecurity policy sqrrl platform relies open-source apache accumulo technology accumulo began development 2008 went open source 2011 sqrrl founded summer 2012 use accumulo cybersecurity sqrrl founded washington d.c. quickly moved cambridge massachusetts august 2012 sqrrl announced 2 million seed round led accomplice formerly atlas venture matrix partners october 2013 sqrrl received 5.2 million funding led accomplice matrix partners february 2015 sqrrl raised another 7.1 million funding linked data analysis toolkit january 24 2018 reported sqrrl acquired amazon would become part amazon web services sqrrl ’ main product visual cyber threat hunting platform combines technology link analysis user behavior analytics user entity asset event data combined behavior graph users navigate respond security incidents well search undetected threats sqrrl integrates security information event management siem systems ibm qradar platform also integrates machine learning risk-scoring sqrrl mentioned cyber security industry marketing sc mag ’ top innovator award 2015 2016 2017 cybersecurity excellence award new threat hunting category
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Distributed computing architecture
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rubygems rubygems package manager ruby programming language provides standard format distributing ruby programs libraries self-contained format called gem tool designed easily manage installation gems server distributing created chad fowler jim weirich david alan black paul brannan richard kilmer rubyconf 2004 interface rubygems command-line tool called gem install manage libraries gems rubygems integrates ruby run-time loader help find load installed gems standardized library folders though possible use private rubygems repository public repository commonly used gem management public repository helps users find gems resolve dependencies install rubygems bundled standard ruby package ruby 1.9 development rubygems started november 2003 released public march 14 2004 pi day 2004 2010 default public repository gems moved http //gems.rubyforge.org http //rubygems.org still use also rubygems development moved github 2010 though rubygems existed since ruby 1.8 part standard ruby distribution ruby 1.9 previously compatibility rubygems ruby varied many versions rubygems almost fully incompatible many versions ruby versions key features unusable example ruby 1.9 came rubygems 1.3.7 standard distribution rubygems 1.4.x compatible ruby 1.9 meant updating rubygems ruby 1.9 possible rubygems 1.5.0 released 2011 two years first stable release ruby 1.9 compatibility issues led rapid development rubygems switching 4–6 week release schedule reflected 38 releases 2004 2010 117 releases 2011 2016 45 versions released 2013 highest number releases year rubygems every gem contains name version platform gems work ruby designed particular platform based cpu architecture operating-system type version gem consists code organization follows following structure gem called gem_name gems packages similar ebuilds contain package information along files install gems usually built .gemspec files yaml files containing information gems however ruby code may also build gems directly practice usually used rake codice_1 command used build upload download install gem packages rubygems similar apt-get portage yum npm functionality installation uninstallation listing installed gems listing available gems e.g create rdoc documentation gems adding trusted certificate download install gem search available gems e.g gem command may also used build maintain codice_5 codice_6 files build codice_6 codice_5 file since ruby gems run code application may lead various security issues due installation malicious gems creator malicious gems may able compromise user system server number methods developed counter security threat
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Operating systems
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nick levay nick levay also known rattle american computer security expert hacker president ngo-isac former chief security officer council foreign relations carbon black computer security company boston area 2008 2013 director technical operations information security center american progress public policy research organization rattle subject pioneering profile hacker culture published nashville tennessee 1999 2001 tom cross co-founded industrial memetics built memestreams web log early social networking web site rattle presented phreaknic annual hacker technology convention held nashville 2005 2011 2011 talk counter espionage strategy tactics
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Computer security
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global storage architecture gsa global storage architecture distributed file system created ibm replace andrew file system dce distributed file system
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Computer file systems
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token passing local area network token passing channel access method signal called token passed nodes authorize node communicate contrast polling access methods pre-defined master node well-known examples token ring arcnet range others including fddi fiber distributed data interface popular early mid 1990s token passing schemes degrade deterministically load key reason popular industrial control lans map manufacturing automation protocol advantage contention based channel access csma/cd early ethernet collisions eliminated channel bandwidth fully utilized without idle time demand heavy disadvantage even demand light station wishing transmit must wait token increasing latency types token passing schemes need explicitly send token systems process passing token implicit example channel access method used contention free time slots itu-t g.hn standard high-speed local area networking using existing home wires power lines phone lines coaxial cable
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Internet protocols
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quikscript quikscript simulation language derived simscript based 20-gate
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Programming language topics
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orbada orbada free tool database developers sql developers administrators software includes many wizards special features help database administrator job using java jdbc drivers allows users connect multiple databases orbada provided dedicated plug-in databases oracle sqlite firebird hsqldb derbydb help syntax highlighting database browser profiler tool still developed additional plug-ins program distributed gnu general public license
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Databases
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simscript simscript free-form english-like general-purpose simulation language conceived harry markowitz bernard hausner rand corporation 1962 implemented fortran preprocessor ibm 7090 designed large discrete event simulations influenced simula though earlier versions released public domain simscript commercialized markowitz company california analysis center inc. caci produced proprietary versions simscript i.5 simscript ii.5 simscript ii.5 last pre-pc incarnation simscript one oldest computer simulation languages although military contractor caci released 1971 still enjoys wide use large-scale military air-traffic control simulations simscript iii release 4.0 available 2009 ran windows 7 sun os linux object-oriented features 1997 simscript iii already gui interface compiler latest version release 5 earlier versions already supported 64-bit processing pl/i implementation developed 1968-1969 based public domain version released rand corporation
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Programming language topics
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programming language theory programming language theory plt branch computer science deals design implementation analysis characterization classification programming languages individual features falls within discipline computer science depending affecting mathematics software engineering linguistics even cognitive science well-recognized branch computer science active research area results published numerous journals dedicated plt well general computer science engineering publications ways history programming language theory predates even development programming languages lambda calculus developed alonzo church stephen cole kleene 1930s considered world first programming language even though intended model computation rather means programmers describe algorithms computer system many modern functional programming languages described providing thin veneer lambda calculus many easily described terms first programming language invented plankalkül designed konrad zuse 1940s publicly known 1972 implemented 1998 first widely known successful high-level programming language fortran developed 1954 1957 team ibm researchers led john backus success fortran led formation committee scientists develop universal computer language result effort algol 58 separately john mccarthy mit developed lisp programming language based lambda calculus first language origins academia successful success initial efforts programming languages became active topic research 1960s beyond key events history programming language theory since several fields study either lie within programming language theory profound influence many considerable overlap addition plt makes use many branches mathematics including computability theory category theory set theory formal semantics formal specification behaviour computer programs programming languages three common approaches describe semantics meaning computer program denotational semantics operational semantics axiomatic semantics type theory study type systems tractable syntactic method proving absence certain program behaviors classifying phrases according kinds values compute many programming languages distinguished characteristics type systems program analysis general problem examining program determining key characteristics absence classes program errors program transformation process transforming program one form language another form comparative programming language analysis seeks classify programming languages different types based characteristics broad categories programming languages often known programming paradigms metaprogramming generation higher-order programs executed produce programs possibly different language subset original language result domain-specific languages languages constructed efficiently solve problems particular part domain compiler theory theory writing compilers generally translators programs translate program written one language another form actions compiler traditionally broken syntax analysis scanning parsing semantic analysis determining program optimization improving performance program indicated metric typically execution speed code generation generation output equivalent program target language often instruction set cpu runtime systems refers development programming language runtime environments components including virtual machines garbage collection foreign function interfaces conferences primary venue presenting research programming languages well known conferences include symposium principles programming languages popl programming language design implementation pldi international conference functional programming icfp international conference object oriented programming systems languages applications oopsla international conference architectural support programming languages operating systems asplos notable journals publish plt research include acm transactions programming languages systems toplas journal functional programming jfp journal functional logic programming higher-order symbolic computation
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Programming language topics
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igor muttik igor muttik born 1962 russia computer security expert researcher inventor dr. igor muttik senior principal research architect mcafee part intel corporation since 2011 started researching computer malware 1980s anti-virus industry infancy muttik holds phd degree physics mathematics moscow state university member caro computer antivirus research organization since 1994 lives uk worked virus researcher dr. solomon ’ software since 1998 muttik running mcafee ’ anti-malware research emea switched architectural role 2002 2008 one co-founders amtso anti-malware testing standards organization board amtso 3 years muttik also co-founder industry connections security group icsg part ieee chair taggant system working group vice-chair icsg cmx clean file metadata exchange working groups taggant system cmx part amss anti-malware support service regular speaker major international security conferences like black hat briefings rsa conference def con virus bulletin eicar muttik visiting professor information security group royal holloway university london heading mcafee work security research mobile devices funded epsrc mobsec acid appguarden projects current work focused architecture security solutions smart devices hardware-assisted security technologies may 2009 muttik blog risks associated use software packers caused criticism rob rosenberger despite incident muttik working closely today several software companies developing software packers like themida taggant system
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Computer security
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okta identity management okta inc. publicly traded identity access management company based san francisco provides cloud software helps companies manage secure user authentication modern applications developers build identity controls applications website web services devices founded 2009 initial public offering 2017 valued 6 billion okta sells six services including single sign-on solution allow users log variety systems using one centralized process example company claims ability log gmail workday salesforce slack one login also offers api authentication services okta services built top amazon web services cloud january 2019 okta ceo announced company 100 million registered users okta founded 2009 current okta ceo founder todd mckinnon previously served senior vice president engineering salesforce prior salesforce held various roles peoplesoft founders include okta coo frederic kerrest also previously salesforce 2015 company raised 75 million venture capital andreessen horowitz greylock partners sequoia capital valuation 1.2 billion previously raised 150 million across earlier funding rounds 2017 initial public offering raised additional 187 million. /ref traded first day time ipo sequoia capital biggest shareholder 21.2 percent stake company headquartered san francisco also offices san jose bellevue toronto washington d.c. london amsterdam sydney paris stockholm okta primarily targets enterprise businesses current customers include jetblue nordstrom mgm resorts international u.s. department justice runs annual “ oktane ” user conference recently featured former president barack obama keynote speaker
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Distributed computing architecture
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comparison programming languages array comparison programming languages array compares features array data structures matrix processing 48 various computer programming languages following list contains syntax examples determine dimensions index first element last element size elements note particularly languages index zero others index one least since dijkstra famous essay zero-based indexing seen superior new languages tend use following list contains syntax examples access single element array following list contains syntax examples range element array accessed following table compiled languages ada fortran scripting languages idl matlab s-lang native support vectorized operations arrays example perform element element sum two arrays produce third necessary write addition support vectorized arithmetic relational operations languages also vectorize common mathematical functions sine example array result array whose elements sine corresponding elements array vectorized index operations also supported example one would use fortran create arrays even odd entries array another common use vectorized indices filtering operation consider clipping operation sine wave amplitudes larger 0.5 set 0.5 using s-lang done
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Programming language topics
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einstein us-cert program einstein also known einstein program originally intrusion detection system monitors network gateways government departments agencies united states unauthorized traffic software developed united states computer emergency readiness team us-cert operational arm national cyber security division ncsd united states department homeland security dhs program originally developed provide situational awareness civilian agencies first version examined network traffic subsequent versions examined content current version einstein significantly advanced einstein product u.s. congressional presidential actions early 2000s including e-government act 2002 sought improve u.s. government services internet einstein mandate originated homeland security act federal information security management act 2002 homeland security presidential directive hspd 7 issued december 17 2003 federal computer incident response capability fedcirc one four watch centers protecting federal information technology e-government act 2002 designated primary incident response center fedcirc core us-cert formed 2003 partnership newly created dhs cert coordination center carnegie mellon university funded u.s. department defense us-cert delivered einstein meet statutory administrative requirements dhs help protect federal computer networks delivery essential government services einstein implemented determine government cyber attack einstein collecting flow data civilian agencies compared flow data baseline november 20 2007 accordance office management budget omb memo einstein version 2 required federal agencies except department defense united states intelligence community agencies executive branch einstein deployed 2004 2008 voluntary 2005 three federal agencies participated funding available six additional deployments december 2006 eight agencies participated einstein 2007 dhs adopting program department-wide 2008 einstein deployed fifteen nearly six hundred agencies departments web resources u.s. government created einstein automated process collecting correlating analyzing sharing computer security information across federal civilian government einstein protect network infrastructure private sector described 2004 purpose facilitate identifying responding cyber threats attacks improve network security increase resiliency critical electronically delivered government services enhance survivability internet einstein designed resolve six common security weaknesses collected federal agency reports identified omb report 2001 u.s. congress addition program addresses detection computer worms anomalies inbound outbound traffic configuration management well real-time trends analysis us-cert offers u.s. departments agencies health federal.gov domain einstein designed collect session data including us-cert may ask additional information order find cause anomalies einstein finds results us-cert analysis given agency disposition einstein 1 determined civilian agencies know ip space obviously security concern determined agency ip looked like immediately clear agency ip gateways could reasonably instrumented protected gave birth omb tic trusted internet connections initiative three constraints einstein dhs trying address large number access points u.s. agencies low number agencies participating program backward-looking architecture omb trusted internet connections initiative expected reduce government 4,300 access points 50 fewer june 2008 agencies reduced access points 60 requested target omb reset goal latter part 2009 number determined new version einstein planned collect network traffic flow data real time also analyze content communications looking malicious code example e-mail attachments expansion known one least nine measures protect federal networks new version called einstein 2 system automatically detect malicious network activity creating alerts triggered einstein 2 use minimal amount necessary predefined attack signatures come internal commercial public sources einstein 2 sensor monitors participating agency internet access point strictly ... limited trusted internet connections using commercial government-developed software einstein could enhanced create early warning system predict intrusions us-cert may share einstein 2 information federal executive agencies according written standard operating procedures summary form us-cert intelligence law enforcement mission notify provide contact information law enforcement intelligence agencies event occurs falls responsibility version 3.0 einstein discussed prevent attacks shoot ing attack hits target nsa moving forward begin program known “ einstein 3 ” monitor “ government computer traffic private sector sites. ” considered first private sector site program plan devised bush administration controversial given history nsa warrantless wiretapping scandal many dhs officials fear program move forward “ uncertainty whether private data shielded unauthorized scrutiny. ” believe program invade privacy individuals much privacy impact assessment pia einstein 2 published 2008 dhs gave general notice people use u.s. federal networks dhs assumes internet users expect privacy addresses email ip addresses websites visit service providers use information routing dhs also assumes people least basic understanding computers communicate know limits privacy rights choose access federal networks privacy act 1974 apply einstein 2 data system records generally contain personal information indexed queried names individual persons pia first version also available 2004 dhs seeking approval einstein 2 retention schedule flow records alerts specific network traffic related alert may maintained three years example case false alert data deemed unrelated potentially collected error deleted according dhs privacy assessment us-cert 24x7 incident handling response center 2007 us-cert data provided authorized users need know data business security purposes including security analysts system administrators certain dhs contractors incident data contact information never shared outside us-cert contact information analyzed secure data us-cert center began dhs certification accreditation process may 2006 expected complete first quarter fiscal year 2007 march 2007 center retention schedule approved national archives records administration disposition schedule —its records must considered permanent nothing may deleted april 2013 dhs still retention schedule working nppd records manager develop disposition schedules update issued may 2016
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Computer security
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lucky thirteen attack lucky thirteen attack cryptographic timing attack implementations transport layer security tls protocol use cbc mode operation first reported february 2013 developers nadhem j. alfardan kenny paterson information security group royal holloway university london novel variant serge vaudenay padding oracle attack previously thought fixed uses timing side-channel attack message authentication code mac check stage tls algorithm break algorithm way fixed previous attempts mitigate vaudenay attack sense attacks pose significant danger ordinary users tls current form however truism attacks get better time anticipate improvements attacks entirely new attacks may yet discovered — nadhem j. alfardan kenny paterson researchers examined free software implementations tls found examined products potentially vulnerable attack tested attacks successfully openssl gnutls researchers applied responsible disclosure worked software vendors software updates mitigate attacks available time publication martin r. albrecht paterson since demonstrated variant lucky thirteen attack amazon s2n tls implementation even though s2n includes countermeasures intended prevent timing attacks
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Computer security
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open proxy open proxy proxy server accessible internet user generally proxy server allows users within network group i.e closed proxy store forward internet services dns web pages reduce control bandwidth used group open proxy however user internet able use forwarding service anonymous open proxy useful seeking online anonymity privacy help users hide ip address web servers since server requests appear originate proxy server makes harder reveal identity thereby helps preserve perceived security browsing web using internet services real anonymity extensive internet security might achieved measure alone website operators use client-side scripts determine browser real ip address open proxy may keeping logs connections public vpns work open proxies possible computer run open proxy server without computer owner knowing result misconfiguration proxy software running computer infection malware viruses trojans worms designed purpose caused malware infected computer known zombie computer open proxies often implicated abuse number methods developed detect refuse service irc networks strict usage policies automatically test client systems known types open proxies likewise mail server may configured automatically test mail senders open proxies using software codice_1 groups irc electronic mail operators run dnsbls publishing lists ip addresses known open proxies ahbl cbl njabl till 2013 sorbs since 2002
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Computer security
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libscore libscore web-based tool scans one-million popular websites collect statistics javascript library usage collects data jquery plugins javascript variables produced non-jquery plugins javascript libraries loaded via requirejs libscore provides tools intended help developers technical analysts compare relative popularity web frameworks third-party web tools libscore developed via co-sponsorship stripe payments processor digitalocean hosting infrastructure provider libscore founder julian shapiro created project 2014 web development grant awarded stripe major payments processing company developing libscore brokered partnership digitalocean participate project second final sponsor stripe provides legal resources covers cost libscore development digitalocean lends technical resources perform monthly crawling may 2015 libscore nominated net award competing 1,000 submissions june 2015 libscore 2.0 released introduced ability compare popularity libraries time also provided comparative graphing comparing library growth trends one another auto-suggest make library searching easier libscore scans top million sites web determine third-party javascript libraries installed site developers use data determine libraries trending popularity libraries use popular sites libraries market penetrations compare data helps developers perform competitive analysis make informed decisions choosing libraries work site libscore scans runs heuristics determine window variables produced third-party javascript libraries addition catalogues presence external javascript scripts thereafter via libscore homepage users search aggregated data order libscore also provides monthly statistics top libraries scripts sites addition regularly publishing charts showcasing library adoption percentages also libscore api provides developers programmatic access libscore monthly data
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Web technology
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mod lisp mod_lisp extension module apache http server enables apache interface application servers written lisp making possible dynamically generate web pages provide web applications lisp programs unlike mod_* projects mod_perl mod_python mod_lisp embed lisp interpreter apache concept closer fastcgi handling requests serializing textual representation sending socket persistent lisp program sending lisp system response client client may web browser likely reverse proxy server server interacts user browser source freebsd style license lisp examples pre-compiled binaries freebsd linux win32 available mod_lisp web site
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Programming language topics
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windows user windows user component microsoft windows operating system provides core functionality building simple user interfaces component existed versions windows includes functionality window management message passing input processing standard controls windows user provides large part core user experience microsoft windows historically responsible gradually windows become larger better factored windows user cooperated components provide functionality windows user implements abstractions used build windows applications include hwnd basic unit visual display input windows developer platform visual elements either hwnds live part larger hwnd many functions windows user manipulate properties hwnds size position title hwnd also communication channel wndproc window procedure delivery messages windows managed tree desktop window root hierarchy child windows usually always visually contained within parents applications operating system communicate hwnds using messages window message combination target hwnd message code details mouse position combining calls windows user right way windows application processes messages core windows message loop including calls getmessage translatemessage dispatchmessage core windows application developer functionality related windows user provided c header file winuser.h 16-bit versions windows windows user implemented file called user.exe file extension misnomer windows user fact always dynamic link library 32-bit versions windows 32-bit version windows user called user32.dll located system32 directory compatibility 16-bit applications provided modified version user.exe also present 64-bit versions windows 64-bit implementation windows user called user32.dll located system32 directory modified 32-bit version also called user32.dll present syswow64 directory
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Operating systems
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single source truth information systems design theory single source truth ssot practice structuring information models associated data schema every data element mastered edited one place possible linkages data element possibly areas relational schema even distant federated databases reference locations data refer back primary source truth location updates data element primary location propagate entire system without possibility duplicate value somewhere forgotten deployment ssot architecture becoming increasingly important enterprise settings incorrectly linked duplicate de-normalized data elements direct consequence intentional unintentional denormalization explicit data model pose risk retrieval outdated therefore incorrect information common example would electronic health record imperative accurately validate patient identity single referential repository serves ssot duplicate representations data within enterprise would implemented use pointers rather duplicate database tables rows cells ensures data updates elements authoritative location comprehensively distributed federated database constituencies larger overall enterprise architecture ssot systems provide data authentic relevant referable ideal implementation ssot described rarely possible enterprises many organisations multiple information systems needs access data relating entities e.g. customer often systems purchased off-the-shelf vendors modified non-trivial ways various systems therefore needs store version common data entities therefore system must retain copy record hence immediately violating ssot approach defined example erp enterprise resource planning system sap oracle e-business suite may store customer record crm customer relationship management system also needs copy customer record part warehouse dispatch system might also need copy customer data e.g. shipping address cases vendors support modifications always possible replace records pointers ssot organisations one information system wishing implement single source truth without modifying one master system store pointers systems entities three supporting technologies commonly used enterprise service bus esb allows number systems organisation receive updates data changed another system implement single source truth single source system correct data entity must identified changes entity creates updates deletes published via esb systems need retain copy data subscribe update update records accordingly given entity master source must identified sometimes called golden record given system could publish source truth information particular entity e.g. customer also subscribe updates another system information entity e.g. product alternative approach point-to-point data updates become exponentially expensive maintain number systems increases approach increasingly favour architecture mdm system act source truth given entity might necessarily alternative source truth another system typically mdm acts hub multiple systems many could allow source truth updates different aspects information given entity example crm system may source truth aspects customer updated call centre operator however customer may example also update address via customer service web site different back-end database crm system mdm application receives updates multiple sources acts broker determine updates regarded authoritative golden record syndicates updated data subscribing systems mdm application normally requires esb syndicate data multiple subscribing systems customer data integration cdi common application master data management sometimes abbreviated cdi-mdm 4554 primary purpose data warehouse support reporting analysis data combined multiple sources fact data combined according business logic embedded data transformation integration processes means data warehouse often used de facto ssot generally however data available data warehouse used update systems rather dw becomes single source truth reporting multiple stakeholders context data warehouse correctly referred single version truth since versions truth exist operational data sources data originates dw simply reporting mechanism data loaded operational systems software design schema business logic components often repeated multiple different contexts version refers source code address problem concepts ssot also applied software development principals using processes like recursive transcompiling iteratively turn single source truth many different kinds source code match structurally derived ssot
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Databases
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el torito cd-rom standard el torito bootable cd specification extension iso 9660 cd-rom specification designed allow computer boot cd-rom announced november 1994 first issued january 1995 joint proposal ibm bios manufacturer phoenix technologies according el torito specification 32-bit cpu pc bios search boot code iso 9660 cd-rom standard allows booting two different modes either hard disk emulation boot information accessed directly cd media floppy emulation mode boot information stored image file floppy disk loaded cd behaves virtual floppy disk useful computers built 1999 designed boot floppy drive modern computers emulation mode generally reliable method bios assign bios drive number cd drive drive number int 13h assigned 80 hard disk emulation 00 floppy disk emulation arbitrary number bios provide emulation emulation allows older operating systems booted cd making appear booted hard floppy disk el torito also used produce cds boot linux operating systems including grub bootloader cd following multiboot specification el torito spec alludes mac platform id apple computers n't use according legend el torito cd/dvd extension iso 9660 gained name design originated el torito restaurant irvine california 33.684722 -117.852547 supported claim jack allweiss founder future domain inc. states future domain helped establish standard initial two authors curtis stevens phoenix technologies stan merkin ibm
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Computer file systems
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web interoperability web interoperability producing web pages viewable standard compatible web browsers various operating systems windows macintosh linux devices personal computers pcs pdas mobile phones tablets based latest web standards term originated web interoperability pledge promise adhere current html recommendations promulgated world wide web consortium w3c wip w3c initiative started run zdnet anchordesk quite independently issue known cross browsing browser war internet explorer netscape windows internet explorer dominant browser modern web browsers mozilla firefox opera safari supported web standards backward compatibility internet explorer many web pages supported non-standard html tags dom handling script yet well platform-dependent techniques activex harmful web accessibility device independence various activities example web standards project mozilla technology evangelism web standards group also educational activities web essential conference
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Computer architecture
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address space computing address space defines range discrete addresses may correspond network host peripheral device disk sector memory cell logical physical entity software programs save retrieve stored data unit data must address individually located else program unable find manipulate data number address spaces available depend underlying address structure usually limited computer architecture used address spaces created combining enough uniquely identified qualifiers make address unambiguous within address space person physical address address space would combination locations neighborhood town city country elements address space may element address different addresses said space reference different entities example could multiple buildings address 32 main street different towns demonstrating different towns different although similarly arranged street address spaces address space usually provides allows partitioning several regions according mathematical structure case total order memory addresses simply chunks nested domain hierarchies appear case directed ordered tree domain name system directory structure similar hierarchical design postal addresses internet example internet assigned numbers authority iana allocates ranges ip addresses various registries order enable manage parts global internet address space uses addresses include limited following another common feature address spaces mappings translations often forming numerous layers usually means higher-level address must translated lower-level ones way example file system logical disk operates linear sector numbers translated absolute lba sector addresses simple cases via addition partition first sector address disk drive connected via parallel ata must converted logical cylinder-head-sector address due interface historical shortcomings converted back lba disk controller finally physical cylinder head sector numbers domain name system maps names network-specific addresses usually ip addresses turn may mapped link layer network addresses via address resolution protocol also network address translation may occur edge different ip spaces local area network internet iconic example virtual-to-physical address translation virtual memory different pages virtual address space map either page file main memory physical address space possible several numerically different virtual addresses refer one physical address hence physical byte ram also possible single virtual address maps zero one one physical address
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Computer architecture
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commvault commvault publicly traded data protection information management software company headquartered tinton falls new jersey formed 1988 development group bell labs later became business unit network systems incorporated 1996 commvault software used data backup recovery cloud infrastructure management retention compliance commvault business split software licensing services march 1998 bob hammer al bunte joined commvault chairman president ceo vice president coo respectively feb. 5 2019 sanjay mirchandani replaced retiring hammer mirchandani joined commvault puppet oregon-based automation company resided ceo commvault software enterprise-level data platform contains modules back restore archive replicate search data built ground-up single platform unified code base data protected installing agent software physical virtual hosts use operating system application native apis protect data consistent state production data processed agent software client computers backed data manager mediaagent disk tape cloud storage data management activity environment tracked centralized server commserve managed administrators central user interface end users access protected data using web browsers mobile devices 2018 commvault began sell hyperscale backup appliance appliance commvault software pre-integrated hardware customers install directly data centers commvault provides consulting services customers commvault advises customers setting new data management systems architecture design implementation monitoring remote managed service commvault manages software production customers
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Computer security
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cairo operating system cairo code name project microsoft 1991 1996 charter build technologies next generation operating system would fulfill bill gates vision information fingertips cairo never shipped although portions technologies since appeared products cairo announced 1991 microsoft professional developers conference jim allchin demonstrated publicly including demo system attendees use 1993 cairo/win95 pdc microsoft changed stance cairo several times sometimes calling product times referring collection technologies cairo used distributed computing concepts make information available quickly seamlessly across worldwide network computers windows 95 user interface based initial design work done cairo user interface dce/rpc shipped windows nt 3.1 content indexing part internet information server windows desktop search remaining component object file system planned implemented form winfs part windows vista development cancelled june 2006 technologies merged microsoft products microsoft sql server 2008 also known codename katmai subsequently confirmed interview bill gates microsoft planned migrate applications like windows media player windows photo gallery microsoft office outlook etc use winfs data storage back-end
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Operating systems
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localtalk-to-ethernet bridge localtalk-to-ethernet bridge network bridge joins physical layer appletalk networking used previous generations apple computer products ethernet network important class products late 1980s early 1990s ethernet support became universal mac lineup localtalk-to-ethernet bridges performed appletalk bridging others also able bridge protocols using ad-hoc standards one example macip system allowed localtalk-based macs send receive tcp/ip internet packets using bridges go-between hardware devices software mactcp era 1995 software open transport era 1995
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Internet protocols
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independent safeguarding authority independent safeguarding authority isa non-departmental public body england northern ireland wales existed 1 december 2012 merged criminal records bureau crb form disclosure barring service dbs isa created labour government 2007-2010 tabloid media campaign decision set isa followed inquiry headed sir michael bichard set wake soham murders isa oversee new vetting barring scheme england wales northern ireland required working vulnerable groups undergo enhanced vetting procedure allowed commence relevant duties 15 june 2010 new coalition government home secretary theresa may announced plans new applicants jobs working children vulnerable along changing posts would register independent safeguarding authority halted vetting barring scheme would severely scaled back save uk taxpayer around £100 million year home secretary went say protection children vulnerable adults would focus upon common sense rather measures labour introduced said got actually trust people philosophy behind setting isa based upon assumption assumed guilty sense proven innocent told able work children review vetting barring scheme published 11 february 2011 made recommendations merger criminal records bureau independent safeguarding authority one non-departmental public body responsible barring individuals completing criminal record checks protection freedoms act new scheme require registration cases details retained database exception barred whether basis crime basis 'soft intelligence e.g dismissal employer led continued criticism variety organizations bichard report published 22 june 2004 made 31 recommendations recommendation 19 called new registration scheme stated new arrangements introduced requiring wish work children vulnerable adults registered register – perhaps supported card licence – would confirm known reason individual work client groups new register would administered central body would take decision subject published criteria approve refuse registration basis information made available police agencies responsibility judging relevance police intelligence deciding person ’ suitability would lie central body note recommendation use double-negative known reason individual work client groups say isa inception designed clear individuals suitable work vulnerable groups remove pose known risk proposals implement recommendations put public consultation 5 april 2005 results exercise announced rt hon ruth kelly secretary state department education skills 19 january 2006 translated primary legislation safeguarding vulnerable groups act 2006 received royal assent 8 november 2006 within act isa referred independent barring board known isa since august 2007 formally renamed following royal assent policing crime bill 2009 safeguarding vulnerable groups act covers england wales comparable legislation passed cover northern ireland scotland department children schools families known held consultations along creating isa safeguarding vulnerable groups act 2006 defines two categories work whether paid fall within scope act regulated controlled activity regulated activity primary area work covered act broadly deals direct contact vulnerable groups specifically regulated activity covers activity involves contact children vulnerable adults specified nature e.g teaching training care supervision advice treatment transport activity allowing contact children vulnerable adults specified place e.g school children ’ home etc. activity regulated activity must take place frequent intensive basis regulated activity also covers fostering childcare adoption child defined anyone 18 except employment settings age limit 16 addition number defined office holders position prescribed post-holder deemed engaging regulated activity irrespective actual contact vulnerable groups list includes people local authority director children ’ services trustees children ’ charities school governors distinction made paid voluntary work duties responsibilities regulated activity organisation providing activity although serious criminal offence engage regulated activity barred individuals engage regulated activity required register isa prominent example involved domestic employment individuals required register isa employed parents work children vulnerable adult arranges individuals provide care homes examples domestic employment would include groups private tutors employed directly parents individuals involved direct payments scheme policy confirmed government response isa scheme consultation document may 2008 controlled activity much limited area work tightly defined safeguarding vulnerable groups act controlled activity applies mandatory check isa registration status individuals controlled activity although possible employ barred person providing sufficient safeguards put place isa functioned decision-making element new vetting barring scheme application process monitoring functions run criminal records bureau largely retains functions 2012 entirely merged crb operational vetting barring scheme originally designed would required engaged regulated controlled activity register registration status checked would possible 'opt-out scheme would criminal offences non-compliance employer employee apply case barred individual seeks attains work successful original application process would provided unique reference number employers would verify potential employee membership allowing commence duties via free online check estimates time stated number would required register would approximately 11.3 million people quarter adult population criticised press 2009 proposal create intrusive database ever created democracy described later initial proposals withdrawn press hostility led government creation singleton review 2009 subsequent review led eileen munro 2010 cost registration originally set £64 per person except volunteers would free charge fees also withdrawn requirement register abandoned 2010 point isa barred list reshaped simply list barred accessible employers certain others akin predecessor 'list 99 definition volunteer remains used crb volunteer person engaged activity involves spending time unpaid except travelling approved out-of-pocket expenses something aims benefit someone individuals groups addition close relatives aspects original design retained since singleton review isa owns maintains two lists one covering children sector one cover adults barred working vulnerable groups replaced previous barred lists list 99 protection children act 1999 poca scheme relating protection vulnerable adults pova disqualification orders inclusion barred lists result either automatic bar following police caution conviction following discretionary bar typically following dismissal resignation dismissal possible following act gross misconduct work although potential reasons secondary legislation decisions taken isa isa base decisions upon information range sources including limited held police locally police national computer local authorities social services regulatory organisations general medical council general teaching council england supervisory authorities ofsted also receive cases directly employers employer referrals constitute largest number cases considered discretionary barring receive cases directly individuals cases clear decisions escalated within isa final decisions made board chaired former chief executive barnardo roger singleton isa able consider information led cautions convictions include unproven allegations former employers professional bodies members public stories press however referral information allegations lead automatic inclusion isa barred lists barring decision made individual given information decision based opportunity explain case however hearing process caused controversy see case workers allowed undertake appropriate research internet chatrooms social networking websites although published guidance isa decision making process safeguarding vulnerable groups act 2006 state isa satisfied relevant conduct occurred able consider factor safeguarding vulnerable groups act 2006 defines relevant conduct philosophic burden proof whether event occurred balance probability used civil trials rather beyond reasonable doubt required criminal trials case assessment within risk factors obsession sex violence presence severe emotional loneliness and/or inability manage/sustain emotionally intimate relationships age-appropriate adults links anti-social peers presence impulsive chaotic unstable lifestyle using substances sex cope stress considered relation relevant conduct appeal inclusion means administrative court judicial review recent case demonstrates court minded de-register individual bar lawful disproportionate sb v independent safeguarding authority 2011 ukut 404 aac 04 october 2011 decision reflects similar decisions family criminal law regarding risk assessment conviction sexual offences isa barred lists performed separate albeit related role crb disclosure isa decision-making process considered information relating potential risk individual poses vulnerable groups using sources go beyond held police whereas crb disclosure may contain details offences may lead bar example drink driving may pertinent given role driving school bus isa-registration replace crb disclosures 2012 isa crb merged disclosure barring service dbs march 2009 elements vetting barring scheme begun rolled stages linked series pieces secondary legislation safeguarding vulnerable groups act 2006 isa came existence 2 january 2008 31 march 2008 isa began advising ministers barring decisions taken ministers current schemes 20 january 2009 barring decisions england wales began taken isa taking responsibility secretary state extended northern ireland 13 march 2009 20 february 2009 detailed guidance isa decision-making process published 12 october 2009 increased safeguards came effect around five million jobs voluntary positions – including national health service jobs – covered barring arrangements additional safeguards original intention 26 july 2010 new entrants roles working vulnerable groups switching jobs new provider within sectors would able register vbs assessed isa employers would able check registration status online subscribe notified employee registration status changes ability requirement register withdrawn 2011 following singleton munro reviews lists still maintained remains offence employ person regulated activity barred isa person seek work several prominent children authors – believed would required join scheme order conduct talks schools – criticised isa philip pullman called scheme outrageous demeaning insulting said would longer appear schools go school author illustrator talk class time else whole school earth – earth – world anybody going rape assault child circumstances preposterous author screenwriter frank cottrell boyce said author 're never alone class possible reason unless revenue-raising scam former children laureate anne fine said refuse – spoken schools without incident 32 years refuse undergo demeaning process part unhealthy situation 've got people close children seen potential paedophiles lindsay mackie representing literary charity english pen said signal children public space defined potentially dangerous space – values worlds visitors work whether writing engineering family secondary definition adult vetted safe – limiting fearful creating paranoia others questioned usefulness scheme pointing could prevented soham murders first place perpetrator ian huntley knew victims girlfriend job critical media coverage scheme launched 2009 led confusion registration requirements singleton review set due concerns expressed degree contact children trigger requirement register isa sir roger singleton chief adviser safety children chair isa produced ‘ drawing line ’ report check government drawn line right place relation requirement register december 2009 government accepted recommendations found ‘ drawing line ’ report included clarification number areas dcsf published vetting barring myth buster clarify requirements scheme however fact-sheet challenged rather simplistic one-sided several unions professional associations represent effected isa 2009 onwards organizations produced large amount documentation form statements conference resolutions advice either clarifying challenging isa publications referenced including written royal college nursing nurses union national union teachers nut national association schoolmasters union women teachers nasuwt unison union non-teaching staff schools even small sample responses different unions associations significant differences within opinions expressed positions adopted rcn specific branches nasuwt seemingly taking strongest oppositional stance perhaps indicates quite complex child protection debate uk currently 2010 government partly response pressure organizations mentioned launched second review isa led professor eileen munro department social policy london school economics political science lse following munro review 2011 requirement register withdrawn entirely also announced isa would merged crb 2012 isa role maintain lists accessed employers certain bodies barred working either children vulnerable adults changes extent brought end virulent press criticisms isa however also led deeper questioning thinking behind original creation isa specific accusations government overseen many changes reviews showing lack support organization isa initially created knee jerk reaction soham murders philip pullman remains one vociferous critics accusing government using soham murders 'scare story scare british public accepting intrusive database visible opposition isa came large nurses union royal college nursing rcn included successful legal cases brought rcn 2010 several journalists campaigning organizations continued voice criticism including 'civitas 'the manifesto club run journalist josie appleton criticisms concerns commonly raised regarding structure independent safeguarding authority included person barred without hearing minimum standard evidence legal support available 'minded bar right appeal limited single sanction barring 10 years anyone aged 25 refusal independent safeguarding authority use word 'sanction describe barring process formed basis rcn cases organizations continued question basis upon independent safeguarding authority created asking whether bureaucratic solution child protection issues realistic sensible isa accused vociferous critics broadsheets guardian 'unethical 'orwellian rcn campaigning groups ask whether creates problems creating 'climate fear amongst professionals simultaneously creating 'an illusion security amongst public general end pointed recent cases paedophile offences schools committed vanessa george plymouth – 2010 could prevented form database cases others like offender previous criminal disciplinary record debate seems likely continue especially neither pro anti viewpoint regarding expansion systems claimed political party conventional political standpoint right left
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Databases
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4690 operating system 4690 operating system sometimes shortened 4690 os 4690 specially designed point sale operating system originally sold ibm however 2012 ibm sold retail business including product toshiba supports 4690 widely used ibm toshiba retail customers drive retail systems running applications well ibm application client server environment ace supermarket application sa general sales application gsa chain drug sales application cdsa follow-on product ibm 4680 os use ibm customers since 1986 original ibm 4680 os based digital research concurrent dos 286 system soon later renamed flexos 286 july 1993 ibm adopted flexos version 2.32 basis ibm 4690 os version 1 flexos 2.32 supported 286 386 modes limit applications running concurrently 1995 ibm licensed ims real/32 7.50 derivation digital research multiuser dos thereby successor concurrent dos 386 bundle 4695 pos terminals according year store ihl consulting group/ris news ibm 4690 os still market share 12 pos register/client market june 2005 ibm starting phase favour ibm retail environment suse ires ibm continued maintain 4690 os april 2015 recent version released ibm may 2012 ibm 4690 os version 6 release 3 supported 2017 special contracts big-name companies meanwhile toshiba released toshiba 4690 os version 6 release 4 v6r4 january 2014 well version 6 release 5 v6r5 january 2016 retailers using 4690 operating system operations many retail-specific reliability features addition running ibm hardware third-party vendors taken advantage 4690 features competitive hardware 4690 supports number point sale pos terminal devices store controller servers combination controller/terminals 4690 documentation contains list supported pos devices including devices use 20 years family ibm usb pos devices 4690 supports includes keyboards displays cash drawers 4690 also supports i/o devices designed conform ibm usb pos device interface specifications ibm makes interface specifications available third-party vendors enable connect devices pos terminals using rs485 rs232 usb connections ibm provides controller matrix document list compatible ibm servers use 4690 os store controllers controller/terminals servers represent current formerly available devices continue supported 4690 perhaps notable feature 4690 os ability provide redundancy infrastructure ibm designed 4690 os work either single server one 4690 servers servers commonly called store controllers connected lan 4690 store controllers provide redundant backup using mirrored data files using system master controller alternate master file server alternate file server designations controllers preserve data integrity allow file backup event store controller fails needs replaced copy 4690 os maintained store controller 4690 pos terminals registers load copy 4690 store controller memory initial program load ipl 4690 controllers provide terminal support form terminal loading price lookup transaction logging non-volatile memory utilized ensure data lost transit terminals store controller terminals assigned primary store controller controller typically backed another controller primary controller fails terminals automatically access backup controller providing uninterrupted sales pos terminal primary backup controllers unavailable terminal go standalone state applications capable supporting terminal offline tof state wherein terminals run offline using terminal-based item file logging stored within memory order maintain software store level 4690 os provides software maintenance facility manage updates facility provides checking ensure updates transferred store ability apply maintenance store level commands central control updated software applied test preserves prior software case maintenance needs backed reason 4690 supports communications store controller several forms including tcp/ip x.25 sna asynchronous communications following list commands supported 4690 operating system 4690 os updated annually address needs user community anticipation upcoming requirements 4690 version 5 incorporated new security enhancements ssh ipsec enhanced operator security allowing alphanumeric operator ids password complexity requirements password expiration etc. helped users address new security requirements credit card companies another recent addition 4690 capability forward store hardware- software-level events remote management system facilitate central control monitoring file integrity monitoring lockdown 4690s becoming increasingly important due recent breaches caused point-of-sale-malware based threats 4690 supports applications written ibm 4680 basic variant cbasic metaware high-c java 2 java language-based capability server client along extension tcp/ip capability client enables java applications server client run concurrently existing cbasic c applications users make functional enhancements existing applications developing new java application communicates existing application many documents could obtained ibm retail publications download center 2016 toshiba global commerce solutions current owner 4690 os removed public access 4690 related manuals publications servers
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Operating systems
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brian silverman brian silverman canadian computer scientist creator many programming environments children researcher cellular automata silverman student massachusetts institute technology 1970s one creators tinkertoy computer played tic-tac-toe student mit silverman worked seymour papert papert founded logo computer systems inc. 1980 commercialize logo programming language silverman became director research later worked consulting scientist mit media lab ported logo programmable bricks precursor lego mindstorms one developers scratch programming language co-founder along paula bonta mitchel resnick president playful invention company headquartered montreal quebec canada develops programmable cricket spin-off media lab silverman part team reverse-engineered mos technology 6502 intel 4004 microprocessors developed transistor-level emulators ported spacewar one earliest digital computer games java writing another emulator pdp-1 game originally written also invented several well-known cellular automaton rules including brian brain seeds wireworld
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Programming language topics
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shiira shiira シイラ japanese common dolphin-fish discontinued open source web browser mac os x operating system according lead developer makoto kinoshita goal shiira create browser better useful safari shiira used webkit rendering scripting project reached version 2.3 discontinued december 2011 developer website removed since browser developed safari mind main characteristics two browsers similar example shiira employs private browsing options history cookies recorded activated however search engines search field toolbar includes many search engines shiira also uses cocoa programming provide users customizable drawer extending left right window drawer includes bookmarks history downloads rss reader version 2.0 sidebar replaced series palettes opened closed main window toolbar shiira natively supports in-browser pdf viewing features shiira include appearance options users may switch aqua metal styles addition changing buttons appearances however current 2.0 release changes themes yet available tabs also customizable another option tab exposé acts much like exposé feature mac os x tab visible totality enabling users select tab wish navigate 1.x releases shiira also page-turning effect transitions two webpages however dropped 2.x releases new interface shiira 2.0 set display tabs thumbnails along bottom sides window latest release version 2.3 requires mac os x 10.4 later shiira 2.3 tested latest versions os reported buggy mac os x 10.5 10.6 final release mac os x 10.3 1.2.2
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Internet protocols
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thinkpad x series thinkpad x series line notebook computers convertible tablets originally produced ibm marketed lenovo ibm announced thinkpad x series initially x20 september 2000 intention providing “ workers move better experience extra-thin extra-light mobile computing. ” thinkpad x series replaced 240 570 series ibm transition numbered letter series early 2000s first x series laptops slimmer deck cards lighter half-gallon milk despite presence 12.1-inch thin-film transistor tft lcd display design values—thin light—continued integral thinkpad x-series laptops design marketing even purchase ibm personal computing division lenovo first x series thinkpad released lenovo x41 2005 thinkpad x-series laptops lenovo described trusted reviews combining ultraportable weight form factor durable design x-series laptop styles include traditional ultraportables well convertible tablet designs according lenovo thinkpad x-series laptops include low power processors offer long battery life several durability features roll cage magnesium frame around display magnesium alloy covers spill-resistant keyboard currently lacks replaceable battery upgradable ram slots x20 first ibm/lenovo long standing x-series ultraportable line celeron-based configurations thinner case specifications x20 except optional 600 700mhz processor onboard ram could ordered new internal design slim-version dropped svga screen option dropped tualatin cpus faster radeon 7000 8mb gpu communications daughter card/cdc slot optional firewire and/or wifi models 133mhz fsb maximum ram increased 640mb x22 faster processors 800 866mhz bigger hard drives 30gb bluetooth ibm security sub system selected models x23 even faster processors 1.06 1.13ghz full-powered successor x2x line completely redesigned case however shared much technology 830mg chipset intel extreme graphics gpu maximum 1gb ram thanks two ram slots firewire standard models 60gb hard drives available additional secondary extended life battery could purchased x30 updated intel centrino platform pentium cpus faster ram ddr pc2100 better gpu ati radeon 7000 vram 16mb usb2.0 2nd usb port left side gigabit lan introduced models ibm security sub system models first model new thin light sub-line specifications three years release x30 upon acquiring thinkpad division lenovo released thinkpad x41 ultraportable laptop thinkpad x41 tablet x41 tablet convertible capacity function tablet pc ultraportable laptop x32 introduced 2005 numbering system irregular actually introduced x40 using older x3x chassis design also powerful x40 x41 units due use faster full-voltage dothan processors standard 2.5 5400/7200rpm hard drives short-lived model discontinued within months introduction model ibm included gigabit lan security sub system models x32 x41 two last ibm-designed thinkpads lenovo took x41 tablet designed lenovo x-series laptops released 2006 lenovo x60 x60s x60 tablet x60 x60s slimline differed primarily processors x60s low voltage processor x60 gave x60s lower active temperature longer battery life exchange reduced performance x60s also smaller heatsink slightly thinner case different battery form factor although could use standard x60 batteries plastic adapter review thinkpad x60/x60s notebook review called laptop hands best performing ultraportable market raising issues design lack optical drive two laptops available variety configurations later x60 models used 64-bit core 2 duo cpus x60s available lightweight lcd panel typical specifications laptops provided thinkpad x60 tablet praised reviewers laptop magazine said thinkpad x60 tablet raises bar business-class convertibles significant issue raised low capacity 4-cell battery provided battery life two hours x series laptops released lenovo 2007 x61 x61s x61 tablet x61 received mixed user reviews cnet users reporting display problems delivery delays others praised laptop performance portability reviewers however praised ultraportable notebook review called extremely fast ultraportable however criticized display colors viewing angles also pointed palm rest prone heating wireless networking card underneath x61s lauded excellent build quality performance long battery life battery improvement x41 model one last feature 43 aspect ratio display x60s models shipped intel core 2 duo l7300 clocked 1.40ghz l7700 clocked 1.80ghz 2018 still possible purchase new batteries spare parts laptops online retailers thinkpad x61 tablet also received positive reviews reviews saying build quality engineering second none shines tablet features executed something close genius however high price tag relatively inadequate performance criticized reviewer tabletpc review acknowledged sturdiness x61 tablet high battery life quality pen features met disfavor lack widescreen display brightness colors lack optical drive—although reviewer admitted absence helps reduce weight laptops released x series 2008 followed new naming conventions established lenovo x series laptops released lenovo 2008 x200 x200 tablet x300 thinkpad x200 released 15 july 2008 leveraged new technology x300 including options solid-state drive ssd optional integrated camera widescreen display optional 3g mobile broadband card new 9-cell battery extended running time 9.8 hours weight low intel core 2 duo cpu 2.66ghz one last models x-series able run libreboot free software bios replacement lenovo released x200s 23 september 2008 differed standard x200 lighter longer battery life running quietly due owl fan design cooling taken x300 x200s available half dozen different cpus three screen options top range wxga+ led-backlit tn panel x200s features cooler components made possible fan design modeled owl-wings however laptops touchpad trackpoint hdmi dvi displayport built-in optical drive x200 series included tablet pc models designated usage suffix primarily x230t lenovo released x200 tablet 9 september 2008 like tablet-designated models added convertible screen assembly containing touch digitizer pen buttons screen front operating device without access keyboard buttons converted mode codenamed kodachi x300 released distinguished ultraportable laptops use led backlighting removable battery solid-state drive integrated dvd burner thinkpad x300 used small form factor intel gs965 chipset instead standard gm965 chipset along intel core 2 duo l7100 low-voltage cpu 12w thermal design power tdp successor thinkpad x301 uses intel centrino 2 mobile platform gs45 chipset ultra-low-voltage ulv cpu also integrates gps wwan webcam top lid thickest part laptop thinnest part x300 original internal codename razor then-popular motorola razr flip phone lenovo noticed three technologies converging would make possible build thin light fast thinkpad first solid-state storage would replace mechanical hard drives second light-emitting diode led backlighting flat-panel displays would improve battery life image quality third ultrathin optical drives 7mm thick compared 9.5mm 12.7mm used previous thinkpads razor concept eventually merged bento-fly project renamed kodachi price time review notebook review extremely high indicated range corporate users laptop magazine awarded x300 laptop score 4.5 stars among highest thinkpad x-series laptop laptop less inch thick making thinnest thinkpad available time x300 laptop offered quick boot ssd also offered built-in optical drive uncommon thin light notebooks however laptop include sd card reader expansion dock capability expresscard pc card slot x-series laptops released 2010 lenovo x100e x201 x201s x201 tablet thinkpad x100e released 2010 engadget calling laptop perfect solution netbook larger 13- 14-inch ulv ultraportable available two colors heatwave red traditional thinkpad matte black design compared edge series deviated traditional thinkpad design x100e however despite choice colors retained angular edges boxy build scream traditional thinkpad design specifications x100e laptop given modified re-branded low-cost version lenovo x100e named mini 10 issued year 9 students nsw australia start 2010 featured intel atom n450 1.66 ghz processor 160gb hdd 2gb ram 10 1024×600 screen fitted 11.6 frame 0.3mp webcam windows 7 enterprise main 12-inch line-up received internal hardware update new palmrest touchpad x201i model version regular x201 core i3 cpu x201 tablet released 2010 criticized engadget lack durability protruding battery thick body praised performance notebook review similar views x201 tablet terms performance battery life indicating display superior x201 x201s thinkpad x-series laptops released 2011 lenovo x120e x220 x220i x220 tablet x1 thinkpad x120e released march 2011 laptop best affordable business ultraportable ces 2011 laptop specifications given thinkpad x220 released april 2011 new thinner latchless case 16:9 screen laptop magazine received x220 positively praised battery life performance low weight display keyboard significantly improved temperature control however web camera receive favor—while images crisp clear colors reported muted engadget said all-too-familiar thinkpad deceive boring business looks arguably one best laptops 've ever tested notebook review opinion stating thinkpad x220 quite simply best 12-inch business notebook 've reviewed far laptop specifications given x220i uses motherboard chipset standard x220 less powerful intel core i3 processor compared i5 i7 options available x220 another cost-reducing measure x220i offered ips display option x220 tablet also released april 2011 offered specifications x220 laptop terms processor graphics ram battery life x220 tablet nine hours 6-cell battery 18 hours external battery pack 6-cell battery starting weight tablet 3.88 lbs addition lightweight x series weighing 1.36 kg 1.72 kg depending configuration thinnest thinkpad laptop date 16.5 front 21.5 mm rear screen led-backlit hd infinity panel wxga resolution base configuration uses intel sandy bridge 2.5 ghz core i5-2520m 3.20 ghz 4 gb ram 8 gb sata ssd hard drive intel integrated hd graphics usb 3.0 backlit keyboard 802.11 b/g/n wifi average eight hours battery life battery internal removable optical drive thinkpad x1 laptop released lenovo may 2011 notebook review offered positive opinion thinkpad x1 saying powerful notebook combines durability features business-class thinkpad style consumer laptop 13.3 x1 thinkpad announced available uk june 7 2011 specifications thinkpad x1 laptop given thinkpad x-series laptops released 2012 lenovo x1 carbon x131e x230 x230t tablet w l series models thinkpad t430 t430s t530 w530 l430 l530 also released special edition laptop provided australian year 9 students part digital education revolution der program 2012 hardware specifications thinkpad x230 announced replaced earlier x220 x230 uses chassis introduced new chiclet-style 6-row keyboard replacing classic 7-row keyboard style ivy bridge processor first time x-series—usb 3.0 new keyboard design became controversial topic thinkpad community along locked bios discouraged third-party components including batteries wlan cards ivy bridge processors brought performance improvements compared x220 integrated intel hd graphics 4000 capable delivering good gaming experience 4x classic rts games maximum amount installable memory 16gb two memory slots allowing dual-channel ram like x220 possible use msata ssd within second mini pci express slot instead wwan card specifications x230i i3-equipped version regular x230 x230s asian-market model akin x240 instead x230 gained many design ques later found x240 line equipped intel 3rd gen ulv cpus thinkpad x230 tablet announced replaced earlier x220 tablet thinkpad x230t compatible previous series 3 docking stations 4337 4338 compatible ultrabase series 3 slice base x230t touchscreen stylus support whereas x230 touchscreen early august 2012 lenovo released first generation thinkpad x1 carbon announced ref name= release x1 carbon x230 x230t t430 t430s t530 w530 l430 l530 series 3/usb 3.0 dock /ref x1 carbon weighs battery life roughly eight hours start-up time less 20 seconds x1 carbon first released china popularity thinkpads market first x1 carbon featured m.2 ssd instead 2.5 hard drive bay base model 4gb memory intel core i5-3317u processor 128gb ssd expensive model intel core i7 processor 256gb ssd x1 carbon requires dongle connect ethernet cable models include 3g cellular modem first-generation x1 carbon tn-panel lcd display resolution 169 aspect ratio x1 carbon weighs measures x1 carbon case made light carbon fiber matte black finish carbon also marketed thinnest 14 ultrabook review published cnet dan ackerman wrote first glance thinkpad x1 carbon looks lot like thinkpads hand stands light portable excellent keyboard shows ultrabooks rugged build quality reassuring slightly boosted battery maybe lower starting price could serious contender all-around favorite thin laptop peter bright wrote disparaging review ars technica found new x1 carbon adaptive keyboard near perfect unusable keyboard non-standard compared desktop older thinkpad t410s lenovo helix keyboards touch typist despaired removal function keys layout cited repositioning caps lock key replacing home/end positioning backspace delete keys november 2012 lenovo announced touch-screen variant called thinkpad x1 carbon touch designed use windows 8 display makes use multi-touch technology detect simultaneous inputs ten fingers performance x1 carbon touch ssd engadget states machine boots start screen 11 seconds pretty typical windows 8 machine specs like also found solid-state drive delivers equally strong read write speeds 551mb/s 518mb/s respectively noticed last time tested ultrabook intel ssd thinkpad x series laptops released 2013 lenovo x240 x140e thinkpad helix convertible tablet thinkpad x240 replaced earlier x230 x230s compared x230 x240 changed higher-power intel core cpus labelled mobile class lower-power cpus labelled ultrabook class depending cpu model change resulted 10 –20 reduction cpu performance compared older higher power ivy bridge generation cpus first x-series laptop forgo classic trackpoint buttons favor touchpad also pushed x240 reduced maximum physical memory 8gb one memory slot making dual-channel unavailable compared 16gb dual-channel two memory slots x230 lost dedicated insert key volume control keys x240 uses rectangular slim tip power plug x240s slimmed lighter asian-market-only version x240 docking port missing power bridge hot-swappable battery replaced two internal batteries rated 23.5wh extension removes option install larger 6-cell batteries place default 3-cell thinkpad helix released option corporate buyers looking power high-end ultrabook mobility tablet thinkpad helix featured tablet powered ivy bridge components docking keyboard wacom digitizer stylus x131e laptop designed education market comes three versions chrome os windows dos durable case fitted rubber bumpers thickened plastic case components improve durability display panel resolution anti-glare coating customized various colors school logos asset tagging x131e comes several processor versions intel celeron/core i3 amd e1/e2 models basically x130e including sim card slots cellular network access including wireless wan wwan cards x131e last thinkpad classic round power plug thinkpad x series laptops released 2015 lenovo third-generation x1 carbon x250 ces congress thinkpad x250 broadwell processor x250 saw return separate trackpoint buttons one ram slot touch screen available model x250 uses rectangular power plug thinkpad x series laptops released 2016 lenovo ces congress replaced earlier thinkpad x250 thinkpad x260 adopts skylake processors adds additional usb 3.0 port usb-c missing replaces vga port hdmi port addition existing mini displayport port lenovo claims x260 achieve battery life 21.5 hours full charge first generation x1 yoga released 2016 featuring touchscreen 360-degree hinge unlike many laptops x1 series features stylus dedicated slot like many others x1 series x1 yoga features built-in fingerprint sensor multiple usb ports hdmi port support intel i7 processors thinkpad x1 tablet modular device uses lenovo calls ultra connect system tie together removable modules extra battery pack pico projector 3d camera detachable keyboard etc x1 tablet powered intel core m7 processor paired 16gb memory solid state drives 1tb capacity x1 tablet 12-inch multi-touch screen resolution 32 aspect ratio thinkpad x270 announced december 2016 tn ips displays available hd fhd well fhd touch screen option lenovo claims x270 achieve 20 hours battery life full charge includes one usb-c port supporting usb 3.1 gen 1 speed 5gbit/s pd charging via usb-c hdmi two usb type-a 3.0 ports one always allowing users charge items plugged laptop asleep first x line feature charging docking usb-c thunderbolt unlike previous models series soldered ram non-removable battery built-in rj45 ethernet port although one available via extension cable users contended eliminates several central appeals x2* series effectively represents replication lenovo existing lines rather true continuation series update x280 case screen x390 amd processor
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Computer architecture
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similarweb similarweb website provides web analytics services businesses company offers customers information clients competitors website traffic volumes referral sources including keyword analysis website stickiness e.g. time site page views bounce rate among features like alexa internet extrapolates data panel web users allow monitor internet activity combined direct observations subset internet properties websites traffic statistics 2019 claimed world largest panel hundreds millions users company founded 2007 offer tel-aviv israel 2009 similarweb first israeli seedcamp attracting attention international media investors company raised series round 1.1 million investment led yossi vardi docor international management similarsites browser extension help users find sites similar visiting launched later year september 24 2013 company closed 6 million series b round led david alliance moshe lichtman participation existing investor docor international management february 24 2014 south africa media giant naspers invested 18 million similarweb leading series c round within month similarweb used part capital acquisition israeli early-stage company tapdog million dollars shares cash less year tapdog founded november 2014 raised 15 million series investment july 2015 similarweb acquired personalized content discovery platform developer swayy december 10 2015 similarweb announced acquired quettra silicon valley-based mobile intelligence startup boost mobile operations quettra provided personalization tools developers return detailed mobile telemetry data july 2017 company announced 47 million round financing led viola growth saban ventures participation ce ventures existing investors
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Web technology
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dmz computing computer security dmz demilitarized zone sometimes referred perimeter network screened subnet physical logical subnetwork contains exposes organization external-facing services untrusted network usually larger network internet purpose dmz add additional layer security organization local area network lan external network node access exposed dmz rest organization network firewalled dmz functions small isolated network positioned internet private network design effective allows organization extra time detect address breaches would penetrate internal networks name term demilitarized zone area states military operations permitted dmz seen belonging either party bordering concept applies computing use metaphor dmz example acting gateway public internet neither secure internal network insecure public internet case hosts vulnerable attack provide services users outside local area network e-mail web domain name system dns servers increased potential hosts suffering attack placed specific subnetwork order protect rest network become compromised hosts dmz permitted limited connectivity specific hosts internal network content dmz secure internal network similarly communication hosts dmz external network also restricted make dmz secure internet suitable housing special purpose services allows hosts dmz communicate internal external network intervening firewall controls traffic dmz servers internal network clients another firewall would perform level control protect dmz external network dmz configuration provides additional security external attacks typically bearing internal attacks sniffing communication via packet analyzer spoofing e-mail spoofing also sometimes good practice configure separate classified militarized zone cmz highly monitored militarized zone comprising mostly web servers similar servers interface external world i.e internet dmz contain sensitive information accessing servers within lan like database servers architecture dmz usually application firewall ftp cmz hosts web servers database servers could cmz lan separate vlan altogether service provided users external network placed dmz common services web servers communicate internal database require access database server may publicly accessible may contain sensitive information web servers communicate database servers either directly application firewall security reasons e-mail messages particularly user database confidential typically stored servers accessed internet least insecure manner accessed email servers exposed internet mail server inside dmz passes incoming mail secured/internal mail servers also handles outgoing mail security compliance legal standards hipaa monitoring reasons business environment enterprises install proxy server within dmz following benefits reverse proxy server like proxy server intermediary used way around instead providing service internal users wanting access external network provides indirect access external network usually internet internal resources example back office application access email system could provided external users read emails outside company remote user would direct access email server reverse proxy server physically access internal email server extra layer security particularly recommended internal resources need accessed outside worth noting design still allows remote potentially malicious users talk internal resources help proxy since proxy functions relay non-trusted network internal resource may also forward malicious traffic e.g application level exploits towards internal network therefore proxy attack detection filtering capabilities crucial preventing external attackers exploiting vulnerabilities present internal resources exposed via proxy usually reverse proxy mechanism provided using application layer firewall focuses specific shape contents traffic rather controlling access specific tcp udp ports packet filter firewall would reverse proxy usually good substitute well thought dmz design rely continuous signature updates updated attack vectors many different ways design network dmz two basic methods single firewall also known three legged model dual firewalls architectures expanded create complex architectures depending network requirements single firewall least 3 network interfaces used create network architecture containing dmz external network formed isp firewall first network interface internal network formed second network interface dmz formed third network interface firewall becomes single point failure network must able handle traffic going dmz well internal network zones usually marked colors -for example purple lan green dmz red internet often another color used wireless zones secure approach according colton fralick use two firewalls create dmz first firewall also called front-end perimeter firewall must configured allow traffic destined dmz second firewall also called back-end internal firewall allows traffic dmz internal network setup considered secure since two devices would need compromised even protection two firewalls provided two different vendors makes less likely devices suffer security vulnerabilities example security hole found exist one vendor system less likely occur one one drawbacks architecture costly purchase manage practice using different firewalls different vendors sometimes described component defense depth security strategy home routers refer dmz host which—in many cases—is actually misnomer home router dmz host single address e.g. ip address internal network traffic sent otherwise forwarded lan hosts definition true dmz demilitarized zone since router alone separate host internal network dmz host able connect hosts internal network whereas hosts within real dmz prevented connecting internal network firewall separates unless firewall permits connection firewall may allow host internal network first requests connection host within dmz dmz host provides none security advantages subnet provides often used easy method forwarding ports another firewall nat device tactic establishing dmz host also used systems interact properly normal firewalling rules nat forwarding rule formulated ahead time varying tcp udp port numbers example opposed fixed number fixed range also used network protocols router programming handle 6in4 gre tunnels prototypical examples
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Computer security
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cen/xfs cen/xfs xfs extensions financial services provides client-server architecture financial applications microsoft windows platform especially peripheral devices eftpos terminals atms unique financial industry international standard promoted european committee standardization known acronym cen hence cen/xfs standard based wosa extensions financial services wosa/xfs developed microsoft move standardized software base financial institutions increasingly interested ability pick choose application programs drive equipment xfs provides common api accessing manipulating various financial services devices regardless manufacturer chronology wosa/xfs changed name simply xfs standard adopted international cen/isss standards body however commonly called cen/xfs industry participants perceived benefit xfs similar java write run anywhere mantra often different hardware vendors different interpretations xfs standard result differences interpretation means applications typically use middleware even differences various platforms implementation xfs notable xfs middleware platforms include xfs test tools allow testing xfs applications middleware simulated hardware tools include sophisticated automatic regression testing capabilities providers xfs test tools include j/xfs alternative api cen/xfs windows specific also xpeak operating system independent based xml messages j/xfs written java objective provide platform agnostic client-server architecture financial applications especially peripheral devices used financial industry eftpos terminals atms move standardized software base financial institutions increasingly interested ability pick choose application programs drive equipment j/xfs provides common object oriented api pure java application wide range financial devices providing layer separation application device logic implemented using native j/xfs api wrapping existing implementation javapos cen/xfs j/xfs developed companies de la rue ibm ncr wincor nixdorf sun microsystems hosted monitored maintained european committee standardisation cen
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Operating systems
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yie ar kung-fu ii lee young young martial arts master son brave warrior rid china chop suey gang however one member survived declared emperor yie-gah like father lee young rid china yie-gah allies lee young goes three sections level face boss along way meets ninjas power-ups lee acquire oolong tea replenish health lo mein temporary invincibility lee carry three oolong teas time game also features two-player mode player 1 controls lee player 2 choice play either yen pei lan fang po chin making lan fang first ever playable female character fighting game predating chun li street fighter ii five years
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Computer architecture
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scott fahlman scott elliott fahlman born march 21 1948 computer scientist professor emeritus carnegie mellon university notable early work automated planning blocks world semantic networks neural networks particular cascade correlation algorithm dylan programming language common lisp particular cmu common lisp one founders lucid inc. period standardized recognized leader common lisp recently fahlman engaged constructing knowledge base scone based part thesis work netl semantic network fahlman born medina ohio son lorna may dean john emil fahlman received bachelor degree master degree 1973 mit ph.d. mit 1977 master thesis advisor patrick winston doctoral thesis advisor gerald sussman noted doctoral diploma says degree awarded original research demonstrated thesis field artificial intelligence suggested may first use term fellow american association artificial intelligence fahlman acted thesis advisor donald cohen david b. mcdonald david s. touretzky skef wholey justin boyan michael witbrock alicia tribble sagae may 1996 july 2001 fahlman directed justsystem pittsburgh research center fahlman credited originating first smiley emoticon thought would help people message board carnegie mellon distinguish serious posts jokes proposed use purpose symbols caught original message symbols originated posted september 19 1982 message recovered jeff baird september 10 2002 quoted though credited originating smiley emoticons first emoticon user similar marker appeared article reader digest may 1967 interview printed new york times 1969 vladimir nabokov noted often think exist special typographical sign smile — sort concave mark supine round bracket
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Programming language topics
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cross-platform software computing cross-platform software also multi-platform software platform-independent software computer software implemented multiple computing platforms cross-platform software may divided two types one requires individual building compilation platform supports one directly run platform without special preparation e.g. software written interpreted language pre-compiled portable bytecode interpreters run-time packages common standard components platforms example cross-platform application may run microsoft windows linux macos cross-platform programs may run many existing platforms two platforms cross-platform frameworks qt flutter nativescript xamarin phonegap ionic react native exist aid cross-platform development platform refer type processor cpu hardware given operating system application runs type operating system computer combination type hardware type operating system running example common platform microsoft windows running x86 architecture well-known desktop computer platforms include linux/unix macos cross-platform however many devices smartphones also effectively computer platforms less commonly thought way application software written depend features particular platform—either hardware operating system virtual machine runs java platform virtual machine platform runs many operating systems hardware types common platform software written hardware platform refer instruction set architecture example x86 architecture variants ia-32 x86-64 machines often run one version microsoft windows though run operating systems well including linux openbsd netbsd macos freebsd 32-bit arm architectures newer 64-bit version common smartphones tablet computers run android ios mobile operating systems software platforms either operating system programming environment though commonly combination notable exception java uses operating system independent virtual machine compiled code known world java bytecode examples software platforms previously noted java platform exception general rule operating system software platform java language typically compiles virtual machine virtual cpu runs code written language enables executable binary run systems implement java virtual machine jvm java programs executed natively using java processor n't common mostly used embedded systems java code running jvm access os-related services like disk i/o network access appropriate privileges granted jvm makes system calls behalf java application setup allows users decide appropriate protection level depending acl example disk network access usually enabled desktop applications browser-based applets jni also used enable access operating system specific functions currently java standard edition programs run microsoft windows macos several unix-like operating systems several non-unix-like operating systems like embedded systems mobile applications browser plugins used windows mac based devices android built-in support java also subsets java java card java platform micro edition designed resource-constrained devices piece software considered cross-platform must able function one computer architecture operating system developing program time-consuming task different operating systems different application programming interfaces api example linux uses different api application software windows software written particular operating system automatically work architectures operating system supports one example august 2006 openoffice.org natively run amd64 intel 64 lines processors implementing x86-64 standards computers since changed openoffice.org suite software “ mostly ” ported 64-bit systems also means program written popular programming language c c++ mean run operating systems support programming language—or even operating system different architecture web applications typically described cross-platform ideally accessible various web browsers within different operating systems applications generally employ client–server system architecture vary widely complexity functionality wide variability significantly complicates goal cross-platform capability routinely odds goal advanced functionality basic web applications perform processing stateless server pass result client web browser user interaction application consists simple exchanges data requests server responses types applications norm early phases world wide web application development applications follow simple transaction model identical serving static web pages today still relatively common especially cross-platform compatibility simplicity deemed critical advanced functionalities prominent examples advanced web applications include web interface gmail a9.com google maps website live search service bing microsoft advanced applications routinely depend additional features found recent versions popular web browsers dependencies include ajax javascript dynamic html svg components rich internet applications older versions popular web browsers tend lack support certain features competing interests cross-platform compatibility advanced functionality numerous alternative web application design strategies emerged strategies include graceful degradation attempts provide similar functionality users platforms diminishing functionality least common denominator limited client browsers example user attempting use limited-feature browser access gmail may notice gmail switches basic mode reduced functionality differs cross-platform techniques attempt provide equivalent functionality adequate functionality across platforms multiple codebase applications maintain distinct codebases different hardware os platforms equivalent functionality obviously requires duplication effort maintaining code worthwhile amount platform-specific code high strategy relies one codebase may compiled multiple platform-specific formats one technique conditional compilation technique code common platforms repeated blocks code relevant certain platforms made conditional interpreted compiled needed another technique separation functionality disables functionality supported client browsers operating systems still delivering complete application user see also separation concerns technique used web development interpreted code scripting languages query platform running execute different blocks conditionally third-party libraries attempt simplify cross-platform capability hiding complexities client differentiation behind single unified api responsive web design rwd web design approach aimed crafting visual layout sites provide optimal viewing experience—easy reading navigation minimum resizing panning scrolling—across wide range devices mobile phones desktop computer monitors little platform-specific code used technique one complicated aspect cross-platform web application design need software testing addition complications mentioned previously additional restriction web browsers prohibit installation different versions browser operating system although several development approaches companies use target multiple platforms result software requires substantial manual effort testing maintenance across supported platforms techniques full virtualization sometimes used workaround problem using tools page object model cross platform tests scripted way one test case usable multiple versions app long different versions similar user interfaces versions tested one time one test case web applications becoming increasingly popular many computer users still use traditional application software rely client/web-server architecture distinction traditional web applications always clear features installation methods architectures web traditional applications overlap blur distinction nevertheless simplifying distinction common useful generalization traditionally modern computing application software distributed end-users binary file especially executable files executables support operating system computer architecture built for—which means making single cross-platform executable would something massive task generally replaced offering selection executables platforms supported software distributed binary executable software written c c++ programmer must build software different operating system computer architecture i.e must use toolset translates—transcompiles—a single codebase multiple binary executables example firefox open-source web browser available windows macos powerpc x86 apple inc. calls universal binary linux *bsd multiple computer architectures four platforms case windows macos linux *bsd separate executable distributions although come source code use different toolsets perform different builds may sufficient achieve variety working executables different platforms case software engineer must port i.e amend code suitable new computer architecture operating system example program firefox already runs windows x86 family modified re-built run linux x86 potentially architectures well multiple versions code may stored separate codebases merged one codebase conditional compilation see note porting must accompanied cross-platform building reverse case alternative porting cross-platform virtualization allows applications compiled one cpu operating system run system different cpu and/or operating system without modification source code binaries example apple rosetta built intel-based macintosh computers runs applications compiled previous generation macs used powerpc cpus another example ibm powervm lx86 allows linux/x86 applications run unmodified linux/power operating system script considered cross-platform interpreter available multiple platforms script uses facilities provided language script written python unix-like system likely run little modification windows python also runs windows also one implementation python run scripts e.g. ironpython .net framework goes many open-source programming languages available scripting languages unlike binary executable files script used computers software interpret script script generally stored plain text text file may issues however type new line character sits lines generally however little work done make script written one system run another quite popular cross-platform scripting interpreted languages cross-platform multi-platform term also apply video games released range video game consoles specialized computers dedicated task playing games examples cross-platform video games include miner 2049er fifa video game series nhl series minecraft released across variety gaming platforms wii playstation 3 xbox 360 personal computers pcs mobile devices characteristics particular system may lengthen time taken implement video game across multiple platforms video game may initially released platforms later released remaining platforms typically situation occurs new gaming system released video game developers need acquaint hardware software associated new console games may become cross-platform licensing agreements developers video game console manufacturers limit development game one particular console example disney could create game intention release latest nintendo sony game consoles disney license game sony first disney may exchange required release game solely sony ’ console short time indefinitely—effectively prohibiting cross-platform release duration several developers implemented means play games online using different platforms psyonix epic games microsoft valve corporation possess technology allows xbox 360 playstation 3 gamers play pc gamers leaving decision platform use consumers first game allow level interactivity pc console games quake 3 games feature cross-platform online play include rocket league street fighter v killer instinct paragon fable fortune minecraft better together update windows 10 vr editions pocket edition xbox one cross-platform programming practice actively writing software work one platform different ways approaching problem writing cross-platform application program one approach simply create multiple versions program different source trees —in words microsoft windows version program might one set source code files macintosh version might another foss *nix system might another straightforward approach problem potential considerably expensive development cost development time especially corporate entities idea behind create two different programs ability behave similarly also possible means developing cross-platform application result problems bug tracking fixing two different source trees would different programmers thus different defects version another approach used depend pre-existing software hides differences platforms—called abstraction platform—such program unaware platform running could said programs platform agnostic programs run java virtual machine jvm built fashion applications mix various methods cross-platform programming create final application example firefox web browser uses abstraction build lower-level components separate source subtrees implementing platform-specific features like gui implementation one scripting language help facilitate ease portability firefox implements xul css javascript extending browser addition classic netscape-style browser plugins much browser written xul css javascript well number tools available help facilitate process cross-platform programming certain issues associated cross-platform development include
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Computer architecture
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paranoid android software paranoid android open-source operating system smartphones tablet computers based android mobile platform september 2015 pc advisor called famous rom along cyanogenmod economic times called second-largest custom android rom world 200 000 users paranoid android founded paul henschel february 2015 oneplus hired handful key members paranoid android team work new oxygenos caused delays release paranoid android 5.1 builds october 2015 team member matt flaming told android authority project would go hold june 2016 paranoid android team announced back new team members coincided release new version paranoid android based android 6.0.1 marshmallow may security patch includes new customization features june 8 2016 paranoid android supported nexus 6p nexus 5x nexus 6 nexus 5 nexus 4 nexus 7 2013 nexus 9 oneplus one oneplus 2 oneplus x may 31 2017 team announced released nougat flavour paranoid android version based android 7.1.2 nougat notable feature return pie controls supported devices include oneplus 3 3t nexus 5x nexus 6p pixel pixel xl may 12th 2018 paranoid android google+ account posted update status project developers run funds causing website gerrit shut ceasing work oreo builds team stated close release n't able continue without funds looked community donations august 27th 2018 google+ page updated new post titled transparent team apologized lack communication shared info current activities team decided finish device trees release sources discontinuing oreo mr1 basic builds released oneplus 3 3t 5 5t well sony xperia x x compact xz premium xz1 xz2 next goal android pie post saying builds almost stable though time post two commits pie branch released team gerrit also released concept art upcoming feature named blink navigation based gestures pie navigation well rundown new versioning system according economic times two notable features paranoid android halo pie halo included version 5.0 greater floating bubble lets users see notifications without leaving current screen pie replacement onscreen navigation buttons stays screen lets users swipe edge see buttons paranoid android also features substratum theme support alongside color engine accidental touch rejection pocket lock prevents buttons pressed user pocket ability take screenshot swiping three fingers following list devices supported paranoid android interview alex naidis aospa future paranoid android developer advice
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Operating systems
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rm-odp reference model open distributed processing rm-odp reference model computer science provides co-ordinating framework standardization open distributed processing odp supports distribution interworking platform technology independence portability together enterprise architecture framework specification odp systems rm-odp also named itu-t rec x.901-x.904 iso/iec 10746 joint effort international organization standardization iso international electrotechnical commission iec telecommunication standardization sector itu-t rm-odp reference model based precise concepts derived current distributed processing developments far possible use formal description techniques specification architecture many rm-odp concepts possibly different names around long time rigorously described explained exact philosophy example works mario bunge systems thinking example works friedrich hayek concepts—such abstraction composition emergence—have recently provided solid mathematical foundation category theory rm-odp four fundamental elements rm-odp family recommendations international standards defines system interrelated essential concepts necessary specify open distributed processing systems provides well-developed enterprise architecture framework structuring specifications large-scale systems including software systems much preparatory work led adoption rm-odp iso standard carried advanced networked systems architecture ansa project ran 1984 1998 leadership andrew herbert md microsoft research cambridge involved number major computing telecommunication companies parts 2 3 rm-odp eventually adopted iso standards 1996 parts 1 4 adopted 1998 rm-odp consists four basic itu-t recommendations iso/iec international standards complex system specifications extensive single individual fully comprehend aspects specifications furthermore different interests given system different reasons examining system specifications business executive ask different questions system make-up would system implementer concept rm-odp viewpoints framework therefore provide separate viewpoints specification given complex system viewpoints satisfy audience interest particular set aspects system associated viewpoint viewpoint language optimizes vocabulary presentation audience viewpoint viewpoint modeling become effective approach dealing inherent complexity large distributed systems current software architectural practices described ieee 1471 divide design activity several areas concerns one focusing specific aspect system examples include 4+1 view model zachman framework togaf dodaf course rm-odp viewpoint subdivision specification complete system established bring together particular pieces information relevant particular area concern analysis design system although separately specified viewpoints completely independent key items identified related items viewpoints moreover viewpoint substantially uses foundational concepts defined part 2 rm-odp however viewpoints sufficiently independent simplify reasoning complete specification mutual consistency among viewpoints ensured architecture defined rm-odp use common object model provides glue binds together specifically rm-odp framework provides five generic complementary viewpoints system environment currently growing interest use uml system modelling however widely agreed approach structuring specifications adds cost adopting use uml system specification hampers communication system developers makes difficult relate merge system specifications need integrate systems although odp reference model provides abstract languages relevant concepts prescribe particular notations used individual viewpoints viewpoint languages defined reference model abstract languages sense define concepts used represented lack precise notations expressing different models involved multi-viewpoint specification system common feature enterprise architectural approaches including zachman framework 4+1 model rm-odp approaches consciously defined notation- representation-neutral manner increase use flexibility however makes difficult among things development industrial tools modeling viewpoint specifications formal analysis specifications produced possible derivation implementations system specifications order address issues iso/iec itu-t started joint project 2004 itu-t rec x.906|iso/iec 19793 information technology open distributed processing use uml odp system specifications document usually referred uml4odp defines use unified modeling language 2 uml 2 iso/iec 19505 expressing specifications open distributed systems terms viewpoint specifications defined rm-odp defines set uml profiles one viewpoint language one express correspondences viewpoints approach structuring according rm-odp principles purpose uml4odp allow odp modelers use uml notation expressing odp specifications standard graphical way allow uml modelers use rm-odp concepts mechanisms structure large uml system specifications according mature standard proposal allow uml tools used process viewpoint specifications thus facilitating software design process enterprise architecture specification large software systems addition itu-t rec x.906 iso/iec 19793 enables seamless integration rm-odp enterprise architecture framework model-driven architecture mda initiative omg service-oriented architecture soa addition several projects used currently use rm-odp effectively structuring systems specifications 239-item reference list covering rm-odp standards well related research applications case studies included
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Distributed computing architecture
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normalized loop computer science normalized loop sometimes called well-behaved loop loop loop variable starts 0 constant gets incremented one every iteration exit condition met normalized loops important compiler theory loop dependence analysis simplify data dependence analysis well behaved loop normally form increment unitary constant easy see b bigger max loop never access memory outside allocated range non-normalized loop may begin different indexes increment not-unitary amounts exit conditions complicated define loops hard optimize vectorize even traverse especially functions executed part loop conditions simple example n't start beginning increments one complicated example additional exit condition loops also non-predictable behavior compilation time exit condition depends contents data modified even dynamic calculations means function calls reverse loops also simple easily normalized non-normalized n't dynamic behaviour normally easy transform normalized one instance first example example 1 easily converted third example partially normalized allow parallelization still lack ability know loop span many iterations making harder vectorize using multi-media hardware starting 7 much problem long increment regular preferably one multiple statements inside loop use index private temporary variables may created cope different iteration paces reverse loop example 5 also easy normalize note access still backwards case makes sense leave backwards data dependence dependences exist caution must taken revert access well could disrupt order assignments example 4 makes impossible predict anything loop unless functions trivial constant way know loop start stop much 'll increment iteration loops hard parallelize also perform horribly iteration loop evaluate two functions max increment even functions inlined condition becomes complex worth optimizing programmer take extra care create loops unless strictly necessary ever another danger loops appear evaluation depends data modified instance normal error using iterators remove items list modifying relying sizes exit condition true
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Programming language topics
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powerbook 190 powerbook 190 companion powerbook 190cs laptop computers manufactured apple computer part powerbook brand introduced market august 1995 two models differ screen 190 9.5 greyscale display 190cs featured 10.4 color display apple target sales audience model college student need no-frills portable computer terms hardware along powerbook 150 190 much common apple professional laptop period powerbook 5300 series exchange cheaper price point approximately us 2200 compared us 6000 cutting-edge powerbook 5300ce 190 equipped passive matrix lcd rather crisper active matrix screen significantly 5300s ran powerpc 603e processors 100 117 mhz 190 motorola 68lc040 clocked 33 mhz fact 190s last macintoshes use 68k cpu however apple offered ppc upgrade 190 heavily marketed selling point new 68040 macs time addition rather cramped 500 mb ide hard drive standard factory models shipped system 7.5.2 one 100 series powerbooks use original 140 case design thus one include 68040 processor trackpad rather standard trackball along 150 ones provide 14mb ram expansion larger less-expensive ide drives 190 de facto replacement powerbook 500 series completely discontinued introduction 5300 68040-based powerbook apple offered sales figures 190 unavailable event benefit reports exploding battery syndrome similar 5300 factory-default lithium-ion battery could short-circuit burst flames apple quickly offered recall batteries powerbook 190 series used nickel metal hydride battery exhibit problem production 190 halted june 1996 190cs sold october year replaced powerbook 1400cs discontinuation 190 apple abandoned market strategy two strata laptops instead offering low- high-end configurations model number concept would return apple product lineup 1999 introduction consumer-oriented ibook
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Computer architecture
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ricoh 5a22 ricoh 5a22 microprocessor produced ricoh super nintendo entertainment system snes video game console 5a22 based 8/16-bit cmd/gte 65c816 version wdc 65c816 used apple ii personal computer 8-bit data bus 16-bit accumulator 24-bit address bus based mos technology 6502 family processors addition 65c816 cpu core 5a22 contains support hardware including cpu whole employs variable-speed system bus bus access times determined memory location accessed bus runs 3.58 mhz non-access cycles accessing bus b internal registers either 2.68 3.58 mhz accessing bus runs 1.79 mhz accessing controller port serial-access registers works approximately 1.5 mips theoretical peak performance 1.79 million 16-bit operations per second
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Computer architecture
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remastersys remastersys free open-source program debian ubuntu-based linux mint derivative software systems april 28 2013 originator direct development ceased. br project development ceased originator fragadelic group developers members copper linux user group arizona began respin development project fork transition new supporters original code received originator team members discussed fork fork released working version late july 2015 early october 2015 debian principal developer reverted maintaining remastersys kept linux respin open project future features development ubuntu developer/maintainer sergio mejia debian developer/maintainer marcia wilbur keep respin available github launchpad respectively initially created able easily back create distributable copy ubuntu derivative installation inspiration tool came mklivecd script mandriva uses remasterme script pclinuxos since scripts easy port ubuntu written scratch remastersys intended serve easy way create customized live cd/dvd version ubuntu resulting iso also installed usb pendrive creating live usb distro using either command-line approach graphical tool unetbootin future enhancements discussion include possible rescue software incorporated remastersys command line version gui version
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Operating systems
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macintosh operating systems family macintosh operating systems developed apple inc. includes graphical user interface-based operating systems designed use macintosh series personal computers since 1984 well related system software created compatible third-party systems 1984 apple debuted operating system known classic mac os release original macintosh system software system rebranded mac os 1996 preinstalled every macintosh 2002 offered macintosh clones short time 1990s noted ease use also criticized lack modern technologies compared competitors current mac operating system macos originally named mac os x 2012 os x 2016 developed 1997 2001 apple purchase next mac os x brought entirely new architecture based nextstep unix system eliminated many technical challenges classic mac os faced current macos preinstalled every mac updated annually basis apple current system software devices – ios watchos tvos audioos prior introduction mac os x apple experimented several concepts releasing different products designed bring macintosh interface applications unix-like systems vice versa a/ux mae mklinux apple effort expand upon develop replacement classic mac os 1990s led cancelled projects code named star trek taligent copland although different architectures macintosh operating systems share common set gui principles including menu bar across top screen finder shell featuring desktop metaphor represents files applications using icons relates concepts like directories file deletion real-world objects like folders trash overlapping windows multitasking classic mac os original macintosh operating system introduced 1984 alongside first macintosh remained primary use macs 2001 apple released original macintosh january 24 1984 early system software partially based lisa os xerox parc alto computer former apple ceo steve jobs previewed originally named system software simply system apple rebranded mac os 1996 due part macintosh clone program ended year later classic mac os characterized monolithic design initial versions system software run one application time system 5 introduced cooperative multitasking system 7 supports 32-bit memory addressing virtual memory allowing larger programs later updates system 7 enable transition powerpc architecture system considered user-friendly architectural limitations critiqued limited memory management lack protected memory access controls susceptibility conflicts among extensions nine major versions classic mac os released name classic signifies system whole reference compatibility layer helped ease transition mac os x. macos originally named mac os x 2012 os x 2016 current mac operating system officially succeeded classic mac os 2001 although system originally marketed simply version 10 mac os history largely independent classic mac os unix-based operating system built nextstep technology developed next late 1980s early 1997 apple purchased company ceo steve jobs returned apple precursors original release mac os x include openstep apple rhapsody project mac os x public beta macos makes use bsd codebase xnu kernel core set components based upon apple open source darwin operating system macos basis apple operating systems including iphone os/ios watchos tvos audioos first desktop version system released march 24 2001 supporting aqua user interface since several versions adding newer features technologies released since 2011 new releases offered annual basis early server computing version system released 1999 technology preview followed several official server-based releases server functionality instead offered add-on desktop system since 2011 apple real-time operating system environment a/rose small embedded operating system ran macintosh coprocessor platform expansion card macintosh idea offer single overdesigned hardware platform third-party vendors could build practically product reducing otherwise heavy workload developing nubus-based expansion card first version system ready use february 1988 1988 apple released first unix-based os a/ux unix operating system mac os look feel competitive time due part crowded unix market macintosh hardware lacking high-end design features present workstation-class computers a/ux success sales u.s. government posix compliance requirement mac os could meet macintosh application environment mae software package introduced apple 1994 allowed users certain unix-based computer workstations run apple macintosh application software mae used x window system emulate macintosh finder-style graphical user interface last version mae 3.0 compatible system 7.5.3 mae available sun microsystems sparcstation hewlett-packard systems discontinued may 14 1998 announced 1996 worldwide developers conference wwdc mklinux open source operating system started osf research institute apple february 1996 port linux powerpc platform thus macintosh computers mid 1998 community-led mklinux developers association took development operating system mklinux short microkernel linux refers project adaptation linux kernel run server hosted atop mach microkernel mklinux based version 3.0 mach star trek boldly go mac gone relatively unknown secret prototype beginning 1992 whose goal create version classic mac os would run intel-compatible x86 personal computers partnership apple support intel project instigated novell looking integrate dr-dos mac os gui mutual response monopoly microsoft windows 3.0 ms-dos team consisting four apple four novell able get macintosh finder basic applications quicktime running smoothly x86 architecture project canceled year later early 1993 code later reused porting mac os powerpc taligent portmanteau talent intelligent name object-oriented operating system company dedicated producing started project within apple provide replacement classic mac os later spun joint venture ibm part aim alliance purpose building competing platform microsoft cairo nextstep development process never worked taligent often cited example project death march apple pulled project 1995 code delivered copland project apple create updated version classic mac os introduced protected memory preemptive multitasking number new underlying operating system features yet still compatible existing mac software originally planned follow-up release known gershwin would add multithreading advanced features new features added rapidly could completed completion date slipped future sign release 1996 apple decided cancel project outright find suitable third-party system replace copland development ended august 1996 december 1996 apple announced buying next nextstep operating system arrival macintosh 1984 apple history operating systems began apple ii series computers 1977 ran apple dos prodos later gs/os apple iii 1980 ran apple sos apple lisa 1983 ran lisa os later macworks xl macintosh emulator apple also developed newton os newton personal digital assistant 1993 1997 recent years apple also launched several new operating systems based core macos including ios 2007 iphone ipad ipod touch mobile devices watchos 2015 apple watch tvos 2015 apple tv set-top box audioos homepod smart speakers
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Operating systems
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open automotive alliance open automotive alliance oaa alliance automotive manufacturers technology companies aimed using android automobiles announced ces january 6 2014 members open automotive alliance
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Operating systems
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safernet safernet brazilian non-governmental organization combats internet crime partnership federal public ministry facilitates anonymous reporting provides information training internet safety security safernet facilitates anonymous reporting crimes extra consideration preventing investigating child pornography identity theft various hate crimes also works government improve legislation internet-related crimes safernet also educates trains mobilizes public issues relating rights safety 2006 safernet federal public ministry brought suit google brazilian business unit alleging google policing orkut pages enough prevent pornography hate crimes complying judge ruling google provided requested user information brazilian authorities
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Computer security
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bookmarklet bookmarklet bookmark stored web browser contains javascript commands add new features browser bookmarklets unobtrusive javascripts stored url bookmark web browser hyperlink web page bookmarklets usually javascript programs regardless whether bookmarklet utilities stored bookmarks hyperlinks add one-click functions browser web page clicked bookmarklet performs one wide variety operations running search query extracting data table example clicking bookmarklet selecting text webpage could run internet search selected text display search engine results page another name bookmarklet favelet favlet derived favorite steve kangas bookmarklets.com coined word bookmarklet started create short scripts based suggestion netscape javascript guide tantek çelik called scripts favelets used word early 6 september 2001 personal email brendan eich developed javascript netscape gave account origin bookmarklets increased implementation content security policy csp websites caused problems bookmarklet execution usage 2013-2015 suggesting hails end death bookmarklets william donnelly created work-around solution problem specific instance loading referencing using javascript library code early 2015 using greasemonkey userscript firefox pale moon browser add-on extension simple bookmarklet-userscript communication protocol allows library-based bookmarklets executed websites including using csp https // uri scheme note however if/when browsers support disabling/disallowing inline script execution using csp if/when websites begin implement feature break fix web browsers use uris codice_1 attribute tag bookmarks uri scheme codice_2 codice_3 codice_4 specifies protocol format rest string browsers also implement prefix codice_5 parser like uri internally browser sees specified protocol javascript treats rest string javascript application executed uses resulting string new page executing script access current page may inspect change script returns undefined type rather example string browser load new page result script simply runs current page content permits changes in-place font size color changes without page reload anonymous function return value define function etc. used force script return undefined type javascript function however script includes function definition/redefinition function use_this_globally ... environment populated reason arbitrary script suffixed void ... javascript arbitrary script void 0 bookmarklets saved used normal bookmarks simple one-click tools add functionality browser example installation bookmarklet performed creating new bookmark pasting code url destination field alternatively bookmarklet presented link browsers dragged dropped onto bookmark bar bookmarklet run loading bookmark normally microsoft edge possible add bookmarklet favourites instead right-click link choose 'add reading list bookmarklet run clicking reading list microsoft edge reading list favourites opened using icon pile lines example bookmarklet performs wikipedia search highlighted text web browser window normal use following javascript code would installed bookmark browser bookmarks toolbar selecting text clicking bookmarklet performs search javascript function function se se document i=0 frames.length i++ se frames .document || s== prompt 'enter 20search 20terms 20for 20wikipedia open 'https //en.wikipedia.org '/w/index.php title=special search search= encodeuricomponent .focus bookmarklets modify location e.g save web page wayback machine javascript location.href='https //web.archive.org/save/'+document.location.href open new web browser window tab e.g show source web resource web browser supports view-source uri scheme javascript void window.open 'view-source '+location show info related current url e.g. javascript alert '\tdocument.url\n'+document.url+'\n\tdocument.lastmodified\n'+document.lastmodified+'\n\tlocation\n'+location among things
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Programming language topics
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hope programming language hope small functional programming language developed 1970s university edinburgh predates miranda haskell contemporaneous ml also developed university hope derived npl simple functional language developed rod burstall john darlington work program transformation npl hope notable first languages call-by-pattern evaluation algebraic data types hope named sir thomas hope c. 1681–1771 scottish agricultural reformer hope park square edinburgh location department artificial intelligence time development hope also named factorial program hope changing order clauses change meaning program hope pattern matching always favors specific patterns less specific ones explicit type declarations hope required option use type-inference algorithm hope hope provides two built-in data structures tuples lists first implementation hope strict since one lazy versions strict versions lazy constructors british telecom embarked project imperial college implement strict version first release coded thanos vassilakis 1986 releases coded mark tasng british telecom roger bailey hope tutorial august 1985 issue byte references interpreter ibm pc dos 2.0
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Programming language topics
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identity driven networking identity driven networking idn process applying network controls network device access based identity individual group individuals responsible operating device individuals identified network tuned respond presence context osi model provides method deliver network traffic system application requested listening data applications operate either system based user-daemon process may user application web browser internet security built around idea ability request respond requests subjected degree authentication validation authorization policy enforcement identity driven networking endeavors resolve user system based policy single management paradigm since internet comprises vast range devices applications also many boundaries therefore ideas resolve connectivity users within boundaries endeavor overlay system identity framework must first decide identity determine use existing controls decide intended new information digital identity represents connectedness real projection identity may incorporate references devices well resources policies systems policies provide entitlements identity claim particular point time space example person may entitled privileges work workplace may denied home hours user gets network usually form machine authentication probably verifies configures system basic level access short mapping user mac address prior process 802.1x simple users authenticate point usual user attempt authenticate system processes daemons started may well require network configuration already performed follows principle network identity device established permitting network connectivity example using digital certificates place hardware addresses trivial spoof device identifiers furthermore consistent identity model account typical network devices routers switches ca n't depend user identity since distinctive user associated device absent capability practice however strong identity asserted network level first task seeking apply identity driven network controls comprises form authentication device level stack since first piece infrastructure placed upon network often network operating system nos often identity authority controls resources nos contains usually printers file shares also procedures authenticate users onto incorporating form single sign-on means flow effect controls seamless many network capabilities made rely upon authentication technologies provisioning access control policy instance packet filtering -firewall content-control software quota management systems quality service qos systems good examples controls made dependent upon authentication
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Computer security
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anderson rule computer science field computer security anderson rule refers principle formulated ross j. anderson nature large databases never free abuse breaches security large system designed ease access becomes insecure made watertight becomes impossible use
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Computer security
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free list free list data structure used scheme dynamic memory allocation operates connecting unallocated regions memory together linked list using first word unallocated region pointer next suitable allocating memory pool objects size free lists make allocation deallocation operations simple free region one would link free list allocate region one would simply remove single region end free list use regions variable-sized one may search region large enough size expensive free lists disadvantage inherited linked lists poor locality reference poor data cache utilization automatically consolidate adjacent regions fulfill allocation requests large regions unlike buddy allocation system nevertheless 're still useful variety simple applications full-blown memory allocator unnecessary requires much overhead
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Operating systems
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prosyst prosyst software gmbh founded cologne 1997 company specializing java software middleware prosyst first commercial application java ee application server 2000 company sold server technology since focused completely osgi solutions 1999 prosyst among first companies join osgi alliance since made important contributions development release osgi specifications release 1–4 prosyst member osgi alliance board directors alongside ibm nokia ntt siemens oracle corporation samsung motorola telcordia additionally members prosyst staff serve several positions osgi alliance recent years prosyst set focus exclusively development osgi related software frameworks bundles remote management systems osgi tools developers including full sdk available download prosyst ’ osgi applications used smarthome devices mobile phone manufacturers network equipment providers cpes white goods manufacturers car manufacturers ehealth market prosyst employs 120 java osgi experts offers osgi related training support slas technical consulting development services member prosyst contributes osgi eclipse java community process nokia forum pro cvta connected vehicle trade association prosyst acquired bosch february 2015 merged bosch group software systems unit bosch software innovations gmbh
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Distributed computing architecture
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war middle earth war middle earth real-time strategy game released zx spectrum msx commodore 64 amstrad cpc ms-dos commodore amiga apple iigs atari st 1988 australian company melbourne house game combined large scale army unit level small scale character level action happened simultaneously game world places could seen map ground level individual characters could also seen larger battles either survived died — gandalf alone could easily defeat hundred orcs battle quite small less 100 units approximately watched ground level otherwise displayed numerically ground level characters could acquire objects talk computer-controlled friendly characters radagast tom bombadil game reviewed 1989 dragon 147 hartley patricia kirk lesser role computers column reviewers gave game 3 5 stars computer gaming world gave game mixed review noting although faithfully recreates events books genuine strategy lacking game plays similarly subsequent playthroughs compute review positive criticizing anticlimactic ending otherwise impressive game faithful middle earth story line spanish magazine microhobby valued game following scores originality 80 graphics 70 motion sound 50 difficulty 100 addiction 80
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Computer architecture
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sega teradrive ibm pc compatible system integrated mega drive developed sega manufactured ibm 1991 teradrive allowed mega drive games played time pc section used possible mega drive pc hardware interact system released japan sega hoped integrating popular mega drive console ibm pc would attract potential customers wishing purchase pc system proved unpopular failed one main processors used system intel 80286 released 1982 however time teradrive released 1991 processor almost 10 years date powerful 25 mhz intel 80486 released 1989 making teradrive central processor 2 generations behind time system also contains motorola 68000 zilog z80 processors used mega drive ran 7.67 mhz 3.58 mhz respectively machine front panel ports included two mega drive pad ports similar design 9-pin male serial ports 2 ps/2 ports right side unit accommodate mouse keyboard system also contained several ports rear order left right 9-pin male serial port 25-pin parallel port connection printer stereo rca jacks composite ntsc video output connection tv analogue rgb monitor connection 2nd 9-pin male serial connector labelled ext similar found rear original mega drive base unit motherboard also spare isa slot available expansion hole rear unit accommodate interface consisted start-up menu several options including file manager dos clock mega drive mode machine included ibm drivers bundled floppy disk enabled properly written software operate machine ram run native mega drive hardware good example shown puzzle construction program one software titles included teradrive included pc-side editor suite changing features falling-block puzzle game playable mega drive side operating system shipped system ibm dos j4.0/v similar pc dos often speculation teradrive specifically designed purpose-made software development kit allow software makers develop software titles mega drive however given release date teradrive years initial mega drive release well availability sega game development hardware unlikely teradrive designed purpose system peripherals included available separately included 2 × mega drive pads 1 × ps/2 mouse 1 × sega branded ps/2 ibm keyboard 1 × 3-button joystick mouse mega drive pads practically identical found mega drive console version monitor manufactured 3rd party company sega branding available separately price ¥79,800 estimated usd 600/gbp £300 time capable displaying 15 khz rgb video signals mega drive hardware 31 khz vga output pc hardware vga connector three models available ranging ¥148,000 usd 1100/gbp £580 ¥248,000 usd 1840/gbp £950 system proved unpopular japanese market ultimately failed production numbers unknown system moderately rare japan although prices rising rapidly due collector demand price buy teradrive june 2003 triple price 2 years prior new pc also discussion stages developed sega leadership ex-ibm executive narutomi likely never got past discussion stages due failure teradrive similar unrelated system manufactured amstrad sold name mega pc pal areas europe australia although boasted higher specification sega teradrive unable act software development kit due inability interact pc mega drive together essentially pc mega drive bundled inside
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Computer architecture
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linkage software programming languages particularly compiled ones like c c++ linkage describes names refer entity throughout whole program one single translation unit codice_1 keyword used c restrict visibility function variable translation unit also valid c++ c++ 98/03 deprecated usage favor anonymous namespaces longer deprecated c++ 11 also c++ implicitly treats codice_2 namespace-scope variable internal linkage unless explicitly declared codice_3 unlike c. name linkage related distinct scope scope name part translation unit visible instance name global scope file-scope c global namespace-scope c++ visible part file scope end end translation unit whether name given external internal linkage name external linkage entity name denotes may referred another translation unit using distinct declaration name scopes within translation unit using distinct declarations name given internal linkage declaration would denote distinct entity although using name entity could referred distinct declarations within translation unit name linkage referred declarations different scopes even within translation unit examples names parameters functions local variables details differ c objects functions types linkage c++ simplified overview linkage languages must done care different languages adorn external symbols differently common idiom uses codice_4 link c++ c code definition 'linkage quoted iso/iec 9899 tc3 c99 standard c uses term identifier article uses name latter c++ uses formalize linkage identifier declared different scopes scope made refer object function process called linkage following common example linkage function codice_5 declared two files function body defined demo2.c via linkage codice_5 called codice_7 inside demo1.c refers codice_5 demo2.c example external linkage function
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Programming language topics
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yahoo assistant yahoo assistant formerly named 3721 internet assistant browser helper object internet explorer developed beijing 3721 technology co. ltd renamed yahoo assistant beijing 3721 technology acquired yahoo 3721 internet assistant together 3721 chinese keywords known spyware microsoft antispyware malware browser hijacker others panda antivirus however yahoo china filed lawsuit beijing sanjiwuxian internet technology co. ltd developer 360safe antispyware identifying yahoo assistant malware 360safe 3721 internet assistant originally released normal client-server application however turned use activex technology install client system later also shipped many sharewares default install options 3721 internet assistant also blamed use flaw microsoft internet explorer install automatically user browsing array 3721 sponsored personal commercial websites microsoft internet explorer yahoo assistant also included 3721 chinese keywords yahoo mail express sometimes whole package internet assistant chinese keywords mail express named yahoo assistant sharewares company says automatic installation ended september 2005 asks user permission installing however ca inc. reported yahoo assistant installation extra components installed without obtaining user consent software also bundled chinese client cga gaming platform 3721 claims 3721 internet assistant includes many useful features ie setting repair security shield removal internet history information blocking ads however installs various windows hooks slow system tries install hooks repeatedly users also reported internet assistant buttons reappeared immediately manual removal using internet explorer customization features blue screen death appeared using internet assistant test using http //www.kephyr.com/popupkillertest shows 3721 internet assistant block roughly half popup methods built-in popup blocker windows xp sp2 turned 3721 internet assistant enable/disable internet explorer extensions except advertisement links extensions installed yahoo products 3721 internet assistant runs multiple rundll32.exe processes one killed windows task manager immediately restarted others thereby resisting efforts user terminate application driver named cnsminkp.sys installed 3721 internet assistant along several hidden windows services uninstallation several files left system visible windows explorer found using tools total commander dos box yahoo assistant also removes 360safe antispyware program competitor without notifying user august 15 2007 beijing court ruled behavior unfair competition 3721 internet assistant together 3721 chinese keywords according interfax regarded chinese internet users hooligan zombie applications uninstall program pair provided 3721 simply redirects users 3721 website simplified chinese thus recognizable except chinese speakers default option web page keep 3721 internet assistant uninstallation following web uninstallation wizard reboot many 3721 files still remain client system pair ranked 1 beijing association online media list chinese malware 2005
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Computer security
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triplestore triplestore rdf store purpose-built database storage retrieval triples semantic queries triple data entity composed subject-predicate-object like bob 35 bob knows fred much like relational database one stores information triplestore retrieves via query language unlike relational database triplestore optimized storage retrieval triples addition queries triples usually imported/exported using resource description framework rdf formats triplestores built database engines scratch others built top existing commercial relational database engines sql-based nosql document-oriented database engines like early development online analytical processing olap databases intermediate approach allowed large powerful database engines constructed little programming effort initial phases triplestore development seems likely native triplestores advantage performance longer period time difficulty implementing triplestores sql although triples may thus stored implementing efficient querying graph-based rdf model mapping sparql onto sql queries difficult adding name triple makes quad store named graph graph database generalized structure triplestore using graph structures nodes edges properties represent store data graph databases might provide index-free adjacency meaning every element contains direct pointer adjacent elements index lookups necessary general graph databases store graph distinct specialized graph databases triplestores network databases
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Databases
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formula language formula language scripting language used lotus notes often referred formula language pronounced at-formula many language elements start -character example selection formula created ray ozzie early development lotus notes borrowed compiler decompiler lotus 1-2-3 spreadsheet unlike spreadsheet language formula language designed primarily string list processing numerical processing originally functional programming language unique text list-handling features inspired ray ozzie prior use icon lisp formula language engine rewritten damien katz notes domino 6 new features added language looping dynamic execution performance improved formula language two parts functions used several places throughout lotus notes important uses commands like menu commands perform actions lotus notes client examples actions commands primarily used formulas triggered user action button formulas possible combine functions example making execution command conditional field value
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Programming language topics
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ousterhout dichotomy ousterhout dichotomy computer scientist john ousterhout categorization high-level programming languages tend fall two groups distinct properties uses system programming languages scripting languages – compare programming large programming small distinction underlies design language tcl system programming languages applications languages usually following properties system programming languages tend used components applications large amounts internal functionality operating systems database servers web browsers applications typically employ complex algorithms data structures require high performance prototypical examples system programming languages include c modula-2 contrast scripting languages glue languages tend following properties scripting languages tend used applications functionality comes programs often implemented system programming languages scripts used glue together programs add additional layers functionality top existing programs ousterhout claims scripts tend short often written less sophisticated programmers execution efficiency less important simplicity ease interaction programs common applications scripting include web page generation report generation graphical user interfaces system administration prototypical examples scripting languages include applescript c shell dos batch files tcl dichotomy fully set though ousterhout drawn distinction since least design tcl 1988 stated publicly various times early episode tcl war late september october 1994 richard stallman posted article critical tcl entitled use tcl ousterhout replied articulation dichotomy many believe dichotomy highly arbitrary refer ousterhout fallacy ousterhout false dichotomy strong-versus-weak typing data structure complexity independent versus stand-alone might said unrelated features usual critique ousterhout dichotomy distinction compiling versus interpreting since neither semantics syntax depend significantly whether code compiled machine-language interpreted tokenized byte-compiled start run mix many languages fall interpreted compiled e.g lisp forth ucsd pascal perl java makes compiling versus interpreting dubious parameter taxonomy programming languages
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Programming language topics
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lexical analysis computer science lexical analysis lexing tokenization process converting sequence characters computer program web page sequence tokens strings assigned thus identified meaning program performs lexical analysis may termed lexer tokenizer scanner though scanner also term first stage lexer lexer generally combined parser together analyze syntax programming languages web pages forth lexer forms first phase compiler frontend modern processing analysis generally occurs one pass older languages algol initial stage instead line reconstruction performed unstropping removed whitespace comments scannerless parsers separate lexer steps done part lexer lexers parsers often used compilers used computer language tools prettyprinters linters lexing divided two stages scanning segments input string syntactic units called lexemes categorizes token classes evaluating converts lexemes processed values lexers generally quite simple complexity deferred parser semantic analysis phases often generated lexer generator notably lex derivatives however lexers sometimes include complexity phrase structure processing make input easier simplify parser may written partly fully hand either support features performance lexeme sequence characters source program matches pattern token identified lexical analyzer instance token authors term token using token interchangeably represent string tokenized token data structure resulting putting string tokenization process word lexeme computer science defined differently lexeme linguistics lexeme computer science roughly corresponds word linguistics confused word computer architecture although cases may similar morpheme lexical token simply token string assigned thus identified meaning structured pair consisting token name optional token value token name category lexical unit common token names consider expression c programming language lexical analysis expression yields following sequence tokens token name might termed part speech linguistics specification programming language often includes set rules lexical grammar defines lexical syntax lexical syntax usually regular language grammar rules consisting regular expressions define set possible character sequences lexemes token lexer recognizes strings kind string found lexical program takes action simply producing token two important common lexical categories white space comments also defined grammar processed lexer may discarded producing tokens considered non-significant separating two tokens codice_2 instead codice_3 two important exceptions first off-side rule languages delimit blocks indenting initial whitespace significant determines block structure generally handled lexer level see phrase structure secondly uses lexers comments whitespace must preserved – examples prettyprinter also needs output comments debugging tools may provide messages programmer showing original source code 1960s notably algol whitespace comments eliminated part line reconstruction phase initial phase compiler frontend separate phase eliminated handled lexer tokenization process demarcating possibly classifying sections string input characters resulting tokens passed form processing process considered sub-task parsing input example text string string n't implicitly segmented spaces natural language speaker would raw input 43 characters must explicitly split 9 tokens given space delimiter i.e. matching string codice_5 regular expression codice_6 tokens could represented xml sentence /sentence s-expression token class represents one possible lexeme lexer often saves enough information reproduce original lexeme used semantic analysis parser typically retrieves information lexer stores abstract syntax tree necessary order avoid information loss case numbers identifiers tokens identified based specific rules lexer methods used identify tokens include regular expressions specific sequences characters termed flag specific separating characters called delimiters explicit definition dictionary special characters including punctuation characters commonly used lexers identify tokens natural use written programming languages tokens often categorized character content context within data stream categories defined rules lexer categories often involve grammar elements language used data stream programming languages often categorize tokens identifiers operators grouping symbols data type written languages commonly categorize tokens nouns verbs adjectives punctuation categories used post-processing tokens either parser functions program lexical analyzer generally nothing combinations tokens task left parser example typical lexical analyzer recognizes parentheses tokens nothing ensure matched lexer feeds tokens parser representation used typically enumerated list number representations example identifier represented 0 assignment operator 1 addition operator 2 etc tokens defined often regular expressions understood lexical analyzer generator lex lexical analyzer generated automatically tool like lex hand-crafted reads stream characters identifies lexemes stream categorizes tokens termed tokenizing lexer finds invalid token report error following tokenizing parsing interpreted data may loaded data structures general use interpretation compiling first stage scanner usually based finite-state machine fsm encoded within information possible sequences characters contained within tokens handles individual instances character sequences termed lexemes example integer lexeme may contain sequence numerical digit characters many cases first non-whitespace character used deduce kind token follows subsequent input characters processed one time reaching character set characters acceptable token termed maximal munch longest match rule languages lexeme creation rules complex may involve backtracking previously read characters example c one l character enough distinguish identifier begins l wide-character string literal lexeme however string characters known certain kind e.g. string literal sequence letters order construct token lexical analyzer needs second stage evaluator goes characters lexeme produce value lexeme type combined value properly constitutes token given parser tokens parentheses really values evaluator function return nothing type needed similarly sometimes evaluators suppress lexeme entirely concealing parser useful whitespace comments evaluators identifiers usually simple literally representing identifier may include unstropping evaluators integer literals may pass string deferring evaluation semantic analysis phase may perform evaluation involved different bases floating point numbers simple quoted string literal evaluator needs remove quotes evaluator escaped string literal incorporates lexer unescapes escape sequences example source code computer program string might converted following lexical token stream whitespace suppressed special characters value due licensing restrictions existing parsers may necessary write lexer hand practical list tokens small general lexers generated automated tools tools generally accept regular expressions describe tokens allowed input stream regular expression associated production rule lexical grammar programming language evaluates lexemes matching regular expression tools may generate source code compiled executed construct state transition table finite-state machine plugged template code compiling executing regular expressions compactly represent patterns characters lexemes might follow example english-based language identifier token might english alphabetic character underscore followed number instances ascii alphanumeric characters and/or underscores could represented compactly string means character a-z a-z followed 0 a-z a-z 0-9 regular expressions finite-state machines generate powerful enough handle recursive patterns n opening parentheses followed statement followed n closing parentheses unable keep count verify n sides unless finite set permissible values exists n takes full parser recognize patterns full generality parser push parentheses stack try pop see stack empty end see example structure interpretation computer programs book typically tokenization occurs word level however sometimes difficult define meant word often tokenizer relies simple heuristics example languages use inter-word spaces use latin alphabet programming languages approach fairly straightforward however even many edge cases contractions hyphenated words emoticons larger constructs uris purposes may count single tokens classic example new york-based naive tokenizer may break space even though better break arguably hyphen tokenization particularly difficult languages written scriptio continua exhibit word boundaries ancient greek chinese thai agglutinative languages korean also make tokenization tasks complicated ways address difficult problems include developing complex heuristics querying table common special-cases fitting tokens language model identifies collocations later processing step lexers often generated lexer generator analogous parser generators tools often come together established lex paired yacc parser generator free equivalents flex/bison generators form domain-specific language taking lexical specification – generally regular expressions markup – emitting lexer tools yield fast development important early development get working lexer language specification may change often often provide advanced features pre- post-conditions hard program hand however automatically generated lexer may lack flexibility thus may require manual modification all-manually written lexer lexer performance concern optimizing worthwhile stable languages lexer run often c html lex/flex-generated lexers reasonably fast improvements two three times possible using tuned generators hand-written lexers sometimes used modern lexer generators produce faster lexers hand-coded ones lex/flex family generators uses table-driven approach much less efficient directly coded approach latter approach generator produces engine directly jumps follow-up states via goto statements tools like re2c proven produce engines two three times faster flex produced engines general difficult hand-write analyzers perform better engines generated latter tools following lexical analysers handle unicode lexical analysis mainly segments input stream characters tokens simply grouping characters pieces categorizing however lexing may significantly complex simply lexers may omit tokens insert added tokens omitting tokens notably whitespace comments common needed compiler less commonly added tokens may inserted done mainly group tokens statements statements blocks simplify parser line continuation feature languages newline normally statement terminator often ending line backslash immediately followed newline results line continued – following line joined prior line generally done lexer backslash newline discarded rather newline tokenized examples include bash shell scripts python many languages use semicolon statement terminator often mandatory languages semicolon optional many contexts mainly done lexer level lexer outputs semicolon token stream despite one present input character stream termed semicolon insertion automatic semicolon insertion cases semicolons part formal phrase grammar language may found input text inserted lexer optional semicolons terminators separators also sometimes handled parser level notably case trailing commas semicolons semicolon insertion feature bcpl distant descendant go though absent b c. semicolon insertion present javascript though rules somewhat complex much-criticized avoid bugs recommend always using semicolons others use initial semicolons termed defensive semicolons start potentially ambiguous statements semicolon insertion languages semicolon-terminated statements line continuation languages newline-terminated statements seen complementary semicolon insertion adds token even though newlines generally generate tokens line continuation prevents token generated even though newlines generally generate tokens off-side rule blocks determined indenting implemented lexer python increasing indenting results lexer emitting indent token decreasing indenting results lexer emitting dedent token tokens correspond opening brace codice_7 closing brace codice_8 languages use braces blocks means phrase grammar depend whether braces indenting used requires lexer hold state namely current indent level thus detect changes indenting changes thus lexical grammar context-free indent–dedent depend contextual information prior indent level generally lexical grammars context-free almost thus require looking back ahead backtracking allows simple clean efficient implementation also allows simple one-way communication lexer parser without needing information flowing back lexer exceptions however simple examples include semicolon insertion go requires looking back one token concatenation consecutive string literals python requires holding one token buffer emitting see next token another string literal off-side rule python requires maintaining count indent level indeed stack indent level examples require lexical context complicate lexer somewhat invisible parser later phases complex example lexer hack c token class sequence characters determined semantic analysis phase since typedef names variable names lexically identical constitute different token classes thus hack lexer calls semantic analyzer say symbol table checks sequence requires typedef name case information must flow back parser semantic analyzer back lexer complicates design
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Programming language topics
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vulnerability computing computer security vulnerability weakness exploited threat actor attacker perform unauthorized actions within computer system exploit vulnerability attacker must least one applicable tool technique connect system weakness frame vulnerability also known attack surface vulnerability management cyclical practice identifying classifying remediating mitigating vulnerabilities practice generally refers software vulnerabilities computing systems security risk often incorrectly classified vulnerability use vulnerability meaning risk lead confusion risk potential significant impact resulting exploit vulnerability vulnerabilities without risk example affected asset value vulnerability one known instances working fully implemented attacks classified exploitable vulnerability—a vulnerability exploit exists window vulnerability time security hole introduced manifested deployed software access removed security fix available/deployed attacker disabled—see zero-day attack security bug security defect narrower concept vulnerabilities related software hardware site personnel vulnerabilities examples vulnerabilities software security bugs constructs programming languages difficult use properly large source vulnerabilities iso 27005 defines vulnerability asset anything value organization business operations continuity including information resources support organization mission ietf rfc 4949 vulnerability committee national security systems united states america defined vulnerability cnss instruction 4009 dated 26 april 2010 national information assurance glossary many nist publications define vulnerability context different publications fismapedia term provide list sp 800-30 give broader one enisa defines vulnerability open group defines vulnerability factor analysis information risk fair defines vulnerability according fair vulnerability related control strength i.e strength control compared standard measure force threat capabilities i.e probable level force threat agent capable applying asset isaca defines vulnerability risk framework data computer security dictionary standards concepts terms authors dennis longley michael shain stockton press defines vulnerability matt bishop dave bailey give following definition computer vulnerability national information assurance training education center defines vulnerability resource either physical logical may one vulnerabilities exploited threat agent threat action result potentially compromise confidentiality integrity availability resources necessarily vulnerable one belonging organization and/or parties involved customers suppliers so-called cia triad basis information security attack active attempts alter system resources affect operation compromising integrity availability passive attack attempts learn make use information system affect system resources compromising confidentiality owasp see figure depicts phenomenon slightly different terms threat agent attack vector exploits weakness vulnerability system related security controls causing technical impact resource asset connected business impact overall picture represents risk factors risk scenario set policies concerned information security management information security management system isms developed manage according risk management principles countermeasures order ensure security strategy set following rules regulations applicable country countermeasures also called security controls applied transmission information called security services vulnerabilities classified according asset class related research shown vulnerable point information systems human user operator designer human humans considered different roles asset threat information resources social engineering increasing security concern impact security breach high fact managers upper management easily know systems applications vulnerabilities perform action manage risk seen misconduct legislations privacy law forces managers act reduce impact likelihood security risk information technology security audit way let independent people certify environment managed properly lessen responsibilities least demonstrated good faith penetration test form verification weakness countermeasures adopted organization white hat hacker tries attack organization information technology assets find easy difficult compromise security proper way professionally manage risk adopt information security management system iso/iec 27002 risk follow according security strategy set forth upper management one key concept information security principle defence depth i.e set multilayer defence system intrusion detection system example class systems used detect attacks physical security set measures protect physically information asset somebody get physical access information asset quite easy make resources unavailable legitimate users sets criteria satisfied computer operating system applications order meet good security level developed itsec common criteria two examples responsible disclosure many refer 'coordinated disclosure first biased word vulnerabilities topic great debate reported tech herald august 2010 google microsoft tippingpoint rapid7 recently issued guidelines statements addressing deal disclosure going forward responsible disclosure first alerts affected vendors confidentially alerting cert two weeks later grants vendors another 45-day grace period publishing security advisory full disclosure done details vulnerability publicized perhaps intent put pressure software procedure authors find fix urgently well respected authors published books vulnerabilities exploit good example security researchers catering needs cyberwarfare cybercrime industry stated approach provide adequate income efforts instead offer exploits privately enable zero day attacks never ending effort find new vulnerabilities fix called computer insecurity january 2014 google revealed microsoft vulnerability microsoft released patch fix microsoft representative called coordinated practices among software companies revealing disclosures mitre corporation maintains list disclosed vulnerabilities system called common vulnerabilities exposures vulnerability classified scored using common vulnerability scoring system cvss owasp collects list potential vulnerabilities aim educating system designers programmers therefore reducing likelihood vulnerabilities written unintentionally software time disclosure vulnerability defined differently security community industry commonly referred kind public disclosure security information certain party usually vulnerability information discussed mailing list published security web site results security advisory afterward time disclosure first date security vulnerability described channel disclosed information vulnerability fulfill following requirement many software tools exist aid discovery sometimes removal vulnerabilities computer system though tools provide auditor good overview possible vulnerabilities present replace human judgment relying solely scanners yield false positives limited-scope view problems present system vulnerabilities found every major operating system including windows macos various forms unix linux openvms others way reduce chance vulnerability used system constant vigilance including careful system maintenance e.g applying software patches best practices deployment e.g use firewalls access controls auditing development throughout deployment lifecycle vulnerabilities related evident pure technical approach even protect physical assets one administrative procedure let maintenance personnel enter facilities people adequate knowledge procedures motivated follow proper care see social engineering security four examples vulnerability exploits common types software flaws lead vulnerabilities include set coding guidelines developed large number static code analysers used verify code follows guidelines
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Computer security
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rooting android rooting process allowing users smartphones tablets devices running android mobile operating system attain privileged control known root access various android subsystems android uses linux kernel rooting android device gives similar access administrative superuser permissions linux unix-like operating system freebsd macos rooting often performed goal overcoming limitations carriers hardware manufacturers put devices thus rooting gives ability permission alter replace system applications settings run specialized applications apps require administrator-level permissions perform operations otherwise inaccessible normal android user android rooting also facilitate complete removal replacement device operating system usually recent release current operating system root access sometimes compared jailbreaking devices running apple ios operating system however different concepts jailbreaking bypass several types apple prohibitions end user including modifying operating system enforced locked bootloader installing non-officially approved available google play applications via sideloading granting user elevated administration-level privileges rooting many vendors htc sony asus google explicitly provide ability unlock devices even replace operating system entirely similarly ability sideload applications typically permissible android devices without root permissions thus primarily third aspect ios jailbreaking giving users administrative privileges directly correlates android rooting rooting lets user-installed applications run privileged commands typically unavailable devices stock configuration rooting required advanced potentially dangerous operations including modifying deleting system files removing pre-installed applications low-level access hardware rebooting controlling status lights recalibrating touch inputs typical rooting installation also installs superuser application supervises applications granted root superuser rights requesting approval user granting said permissions secondary operation unlocking device bootloader verification required remove replace installed operating system contrast ios jailbreaking rooting needed run applications distributed outside google play store sometimes called sideloading android os supports feature natively two ways unknown sources option settings menu android debug bridge however us carriers including prevented installation applications play store firmware although several devices subject rule including samsung infuse 4g lifted restriction devices middle 2011. amazon kindle fire defaults amazon appstore instead google play though like android devices kindle fire allows sideloading applications unknown sources easy installer application amazon appstore makes easy vendors android devices may look sources future access alternate apps may require rooting rooting always necessary rooting android phone lets owner add edit delete system files turn lets perform various tweaks use apps require root access advantages rooting include possibility complete control look feel device superuser access device system files aspects operating system customized real limitation level coding expertise immediately expectable advantages rooted devices include following rooting methods involve use command prompt development interface called android debug bridge adb methods may use specialized applications simple clicking one button devices sometimes even different variants device different hardware configurations thus guide rom root method used device variant different hardware setup risk bricking device recent years new method rooting android devices called systemless root systemless root uses various techniques gain root access without modifying system partition device one example magisk also ability hide root access applications refuse work safetynet protected applications like android pay pokémon go distinction soft rooting third-party application uses security vulnerability root exploit hard-rooting flashing codice_1 binary executable sometimes made phone soft rooted vulnerable malware process rooting varies widely device usually includes exploiting one security bugs firmware i.e. version android os installed device exploit discovered custom recovery image skip digital signature check firmware updates flashed modified firmware update typically includes utilities needed run apps root installed example codice_1 binary open-source one paired superuser supersu application copied location current process path e.g. codice_3 granted executable permissions codice_4 command third-party supervisor application like superuser supersu regulate log elevated permission requests applications many guides tutorials automatic processes exist popular android devices facilitating fast easy rooting process process rooting device may simple complex even may depend upon serendipity example shortly release htc dream htc g1 discovered anything typed using keyboard interpreted command privileged root shell although google quickly released patch fix signed image old firmware leaked gave users ability downgrade use original exploit gain root access manufacturers including lg htc motorola provide official support unlocking bootloader allows rooting without exploiting vulnerability however support may limited certain phones example lg released bootloader unlock tool certain models phones google-branded android google nexus line devices boot-loader unlocked simply connecting device computer boot-loader mode running fastboot protocol command codice_5 accepting warning boot-loader unlocked new system image written directly flash without need exploit past many manufacturers tried make non-rootable phones elaborate protections like droid x usually still rootable way may root exploit available new recently updated phones one usually available within months 2010 tablet smartphone manufacturers well mobile carriers mainly unsupportive third-party firmware development manufacturers expressed concern improper functioning devices running unofficial software related support costs moreover firmware omnirom cyanogenmod sometimes offer features carriers would otherwise charge premium tethering due technical obstacles locked bootloaders restricted access root permissions commonly introduced many devices example late december 2011 barnes noble amazon.com inc. began pushing automatic over-the-air firmware updates 1.4.1 nook tablets 6.2.1 kindle fires removed one method gain root access devices nook tablet 1.4.1 update also removed users ability sideload apps sources official barnes noble app store without modding however community-developed software began grow popular late 2009 early 2010 following statement copyright office librarian congress us allowing use jailbroken mobile devices manufacturers carriers softened position regarding cyanogenmod unofficial firmware distributions manufacturers including htc samsung motorola sony mobile communications actively provide support encourage development 2011 need circumvent hardware restrictions install unofficial firmware lessened increasing number devices shipped unlocked unlockable bootloaders similar nexus series phones device manufacturer htc announced would support aftermarket software developers making bootloaders new devices unlockable however carriers verizon wireless recently continuously blocked oems htc motorola releasing retail devices unlocked bootloaders opting instead developer edition devices sold unsubsidized off-contract similar practice nexus devices premium contract discounts 2014 samsung released security service called knox tool prevents modifying system boot files attempts set e-fuse 0x1 permanently voiding warranty international treaties influenced development laws affecting rooting 1996 world intellectual property organization wipo copyright treaty requires nations party treaties enact laws drm circumvention american implementation digital millennium copyright act dmca includes process establishing exemptions non-copyright-infringing purposes rooting 2001 european copyright directive implemented treaty europe requiring member states european union implement legal protections technological protection measures copyright directive includes exceptions allow breaking measures non-copyright-infringing purposes run alternative software member states vary implementation directive 2010 electronic frontiers australia said unclear whether rooting legal australia anti-circumvention laws may apply laws strengthened copyright amendment act 2006 november 2012 canada amended copyright act new provisions prohibiting tampering digital locks exceptions including software interoperability rooting device run alternative software form circumventing digital locks purpose software interoperability several efforts 2008 2011 amend copyright act bill c-60 bill c-61 bill c-32 prohibit tampering digital locks along initial proposals c-11 restrictive bills set aside 2011 michael geist canadian copyright scholar cited iphone jailbreaking non-copyright-related activity overly-broad copyright act amendments could prohibit free software foundation europe argues legal root flash device according european directive 1999/44/ec replacing original operating system another void statutory warranty covers hardware device two years unless seller prove modification caused defect law copyright related rights regulations 2003 makes circumventing drm protection measures legal purpose interoperability copyright infringement rooting may form circumvention covered law tested court competition laws may also relevant see also european union section india copyright law permits circumventing drm non-copyright-infringing purposes indian parliament introduced bill including drm provision 2010 passed 2012 copyright amendment bill 2012 india signatory wipo copyright treaty requires laws drm circumvention listed us special 301 report priority watch list applied pressure develop stricter copyright laws line wipo treaty new zealand copyright law allows circumvention technological protection measure tpm long use legal non-copyright-infringing purposes law added copyright act 1994 part copyright new technologies amendment act 2008 rooting might legal singapore done provide interoperability circumvent copyright tested court unlocking consumer choice wireless competition act guarantees consumers unlock let others unlock phones digital millennium copyright act dmca rooting illegal united states except exemption u.s copyright office granted exemption law least 2015 2010 response request electronic frontier foundation u.s copyright office explicitly recognized exemption dmca permit rooting ruling library congress affirmed july 26 2010 rooting exempt dmca rules respect circumventing digital locks dmca exemptions must reviewed renewed every three years else expire october 28 2012 us copyright office updated exemption policies rooting smartphones continues legal circumvention accomplished sole purpose enabling interoperability lawfully obtained software applications computer programs telephone handset however u.s copyright office refused extend exemption tablets arguing term tablets broad ill-defined exemption class devices could unintended side effects copyright office also renewed 2010 exemption unofficially unlocking phones use unapproved carriers restricted exemption phones purchased january 26 2013 tim wu professor columbia law school argued 2007 jailbreaking legal ethical plain fun wu cited explicit exemption issued library congress 2006 personal unlocking notes locks used wireless carriers limit ability subscribers switch carriers business decision nothing whatsoever interests protected copyright thus implicate dmca wu claim exemption applies help others unlock device traffic software 2010 2012 u.s copyright office approved exemptions dmca allow users root devices legally still possible employ technical countermeasures prevent rooting prevent rooted phones functioning also unclear whether legal traffic tools used make rooting easy
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Operating systems
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xmk operating system extreme minimal kernel xmk real-time operating system rtos designed minimal ram/rom use achieves goal though almost entirely written c programming language consequence easily ported 8- 16- 32-bit microcontroller xmk comes two independent packages xmk scheduler contains core kernel everything necessary run multithreaded embedded application application programming layer apl provides higher level functions atop xmk scheduler api xmk distribution contains standard libraries libc part development tools target systems
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Operating systems
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framenet computational linguistics framenet project housed international computer science institute berkeley california produces electronic resource based theory meaning called frame semantics framenet reveals example sentence john sold car mary essentially describes basic situation semantic frame mary bought car john different perspective semantic frame thought conceptual structure describing event relation object participants framenet lexical database contains 1,200 semantic frames 13,000 lexical units pairing word meaning polysemous words represented several lexical units 202,000 example sentences framenet largely creation charles j. fillmore developed theory frame semantics project based initially project leader project began 1997 collin baker became project manager 2000 framenet project influential linguistics natural language processing led task automatic semantic role labeling frame schematic representation situation involving various participants props conceptual roles examples frame names codice_1 codice_2 frame framenet contains textual description represents frame definition associated frame elements lexical units example sentences frame-to-frame relations frame elements fe provide additional information semantic structure sentence frame number core non-core fes thought semantic roles core fes essential meaning frame non-core fes generally descriptive time place manner etc. examples include framenet includes shallow data syntactic roles frame elements play example sentences example sentence like born ad 460 framenet would mark noun phrase referring codice_4 fe ad 460 noun phrase corresponding codice_5 frame element details frame elements realized sentence important reveals important information subcategorization frames well possible diathesis alternations e.g john broke window vs. window broke verb lexical units lu lemmas part speech evoke specific frame words lu identified sentence specific lu associated specific frame frame many lus associated one frame many frames share multiple lus typically case lus multiple word senses alongside frame lexical unit associated specific frame elements means annotated example sentences example lexical units evoke codice_16 frame specific perspectivized versions precise include verbs complain grouse lament others frames associated example sentences frame elements marked within sentences thus sentence associated frame codice_1 marked frame element codice_4 ad 460 marked codice_5 start framenet project committed looking evidence actual language use found text collections like british national corpus based example sentences automatic semantic role labeling tools able determine frames mark frame elements new sentences framenet also exposes statistics valences frames number position frame elements within example sentences sentence falls valence pattern occurs two times example sentences framenet namely framenet additionally captures relationships different frames using relations include following framenet proven useful number computational applications computers need additional knowledge order recognize john sold car mary mary bought car john describe essentially situation despite using two quite different verbs different prepositions different word order framenet used applications like question answering paraphrasing recognizing textual entailment information extraction either directly means semantic role labeling tools first automatic system semantic role labeling srl sometimes also referred shallow semantic parsing developed daniel gildea daniel jurafsky based framenet 2002 semantic role labeling since become one standard tasks natural language processing latest version 1.7 framenet fully supported natural language toolkit since frames essentially semantic descriptions similar across languages several projects arisen years relied original framenet basis additional non-english framenets spanish japanese german polish among others
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Computational linguistics
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memsql memsql distributed in-memory sql database management system relational database management system rdbms compiles structured query language sql machine code via termed code generation april 23 2013 memsql launched first generally available version database public fast database memsql combines lock-free data structures just-in-time compilation jit process highly volatile workloads specifically memsql implements lock-free hash tables lock-free skip lists memory fast random access data sql queries sent memsql server converted byte code compiled llvm machine code queries stripped parameters query template stored shared object subsequently matched incoming queries system executing pre-compiled query plans removes interpretation along hot code paths providing highly efficient code paths minimize number central processing unit cpu instructions required process sql statements memsql wire-compatible mysql means applications connect memsql mysql clients drivers well standard open database connectivity odbc java database connectivity jdbc connectors addition mysql syntax functionality memsql also store columns json format supports geospatial datatypes operations memsql store database tables either rowstores columnstores format used determined user ddl time i.e table created data rowstore tables stored completely in-memory snapshots transaction logs persisted disk data columnstore tables stored on-disk using rowstore-like structure handle incoming inserts columnstore rowstore columnstore tables differ storage medium used rowstores name implies store information row format traditional data format used rdbms systems rowstores optimized singleton small insert update delete queries closely associated oltp transactional use cases columnstores optimized complex select queries typically associated olap analytics use cases example large clinical data set data analysis best stored columnar format since queries run typically ad-hoc queries aggregates computed large numbers similar data items memsql database distributed database implemented aggregators leaf nodes memsql binaries used aggregator leaf nodes nearly difference user identifying node aggregator leaf aggregator responsible receiving sql queries breaking across leaf nodes aggregating results back client leaf node stores memsql data processes queries aggregator communication aggregators leaf nodes done network sql syntax memsql uses hash partitioning distribute data uniformly across number leaf nodes memsql durability slightly different in-memory rowstore on-disk columnstore durability in-memory rowstore implemented write-ahead log snapshots similar checkpoints default settings soon transaction acknowledged memory database asynchronously write transaction disk fast disk allows on-disk columnstore actually fronted in-memory rowstore-like structure skiplist structure durability guarantees memsql rowstore apart columnstore durable since data stored disk memsql cluster configured high availability mode every data partition automatically created master slave versions two separate leaf nodes high availability mode aggregators send transactions master partitions send logs slave partitions event unexpected master failure slave partitions take master partitions fully online operation memsql ships installation management monitoring tool called memsql ops installing memsql ops used set distributed memsql database across machines provide metrics running system memsql ops web user interface command line interface starting memsql 4.1 launched september 2015 memsql gives users ability install apache spark part memsql cluster use spark etl tool import data memsql apache spark installed set interactively using memsql ops ops users define extract transform load phases data pipeline import data memsql management monitoring running data pipelines done within ops ui
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Databases
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persistent uniform resource locator persistent uniform resource locator purl uniform resource locator url i.e. location-based uniform resource identifier uri used redirect location requested web resource purls redirect http clients using http status codes purl concept generic used designate redirection service named purl resolver purls used curate url resolution process thus solving problem transitory uris location-based uri schemes like http technically string resolution purl like sef url resolution remainder article oclc purl system proposed implemented oclc online computer library center purl concept developed oclc 1995 purl system implemented using forked pre-1.0 release apache http server software modernized extended 2007 zepheira contract oclc official website moved http //purlz.org z came zepheira name used differentiate purl open-source software site purl resolver operated oclc purl version numbers may considered confusing oclc released versions 1 2 apache-based source tree initially 1999 oclc research public license 1.0 license later oclc research public license 2.0 license http //opensource.org/licenses/oclc2 zepheira released purlz 1.0 2007 apache license version 2.0 purlz 2.0 released beta testing 2010 release never finalized callimachus project implemented purls 1.0 release 2012 oldest purl http resolver operated oclc 1995 september 2016 reached purl.oclc.org well purl.org purl.net purl.com notable purl resolvers include us government printing office http //purl.fdlp.gov operated federal depository library program operation since 1997 purl concept used w3id.org may replace old purl-services purl-technologies 27 september 2016 oclc announced cooperation internet archive resulting transfer resolver service administration interface internet archive service supported newly created software separate previous implementations transfer reenabled ability manage purl definitions disabled oclc hosted service several months service hosted internet archive servers supports access via purl.org purl.net purl.info purl.com oclc redirecting dns requests purl.oclc.org purl.org purl concept allows generalized url curation http uris world wide web purls allow third party control url resolution resource metadata provision url simply address resource world wide web persistent url address world wide web causes redirection another web resource web resource changes location hence url purl pointing updated user purl always uses web address even though resource question may moved purls may used publishers manage information space web users manage purl service independent publisher information purl services thus allow management hyperlink integrity hyperlink integrity design trade-off world wide web may partially restored allowing resource users third parties influence url resolves simple purl works responding http get request returning response type 302 equivalent http status code 302 meaning found response contains http location header value url client subsequently retrieve via new http get request purls implement one form persistent identifier virtual resources persistent identifier schemes include digital object identifiers dois life sciences identifiers lsids persistent identification schemes provide unique identifiers possibly changing virtual resources schemes provide curation opportunities curation virtual resources defined active involvement information professionals management including preservation digital data future use purls criticized need resolve url thus tying purl network location network locations several vulnerabilities domain name system registrations host dependencies failure resolve purl could lead ambiguous state would clear whether purl failed resolve network failure prevented exist purls valid urls components must map url specification scheme part tells computer program web browser protocol use resolving address scheme used purls generally http host part tells purl server connect next part purl domain analogous resource path url domain hierarchical information space separates purls allows purls different maintainers one designated maintainers may administer purl domain finally purl name name purl domain name together constitute purl id permalink purl used permanent/persistent url redirect location requested web resource roughly speaking differences domain name time scale common types purls named coincide http response code return http response codes equivalent purl types purl servers implement purl types http response codes e.g 401 unauthorized clear meanings context http conversation apply process http redirection three additional types purls chain partial clone given mnemonic names related functions purls so-called simple purls provide redirection desired resource http status code hence purl type simple purl 302 intent 302 purl inform web client end user purl always used address requested resource final uri resolved allow continued resolution resource purl changes operators prefer use purls type 301 indicating final uri addressed future requests purl type chain allows purl redirect another purl manner identical 301 302 redirection difference purl server handle redirection internally greater efficiency efficiency useful many redirections possible since web browsers stop following redirections set limit encountered attempt avoid loops purl type 200 active purl purl actively participates creation aggregation metadata returned active purl includes arbitrary computation produce output active purls implemented purlz 2.0 callimachus project may used gather runtime status reports perform distributed queries type data collection persistent identifier desired active purls act similar stored procedure relational databases purl type 303 used direct web client resource provides additional information regarding resource requested without returning resource subtlety useful http uri requested used identifier physical conceptual object represented information resource purls type 303 used often redirect metadata serialization format resource description framework rdf relevance semantic web linked data content use 303 http status code conformant http-range-14 finding technical architecture group world wide web consortium purl type 307 informs user resource temporarily resides different url norm purls types 404 410 note requested resource could found suggests information support http 307 temporary redirect 404 found 410 gone response codes provided completeness purls types 404 410 provided assist administrators marking purls require repair purls types allow efficient indications resource identification failure target resources moved suitable replacement identified purls type clone used solely purl administration convenient method copying existing purl record new purl purl service includes concept known partial redirection request match purl exactly requested url checked determine contiguous front portion purl string matches registered purl redirection occurs remainder requested url appended target url example consider purl url nowiki http//purl.org/some/path/ /nowiki target url nowiki http //example.com/another/path/ /nowiki attempt perform http get operation url nowiki http//purl.org/some/path/and/some/more/data /nowiki would result partial redirection nowiki http //example.com/another/path/and/some/more/data /nowiki concept partial redirection allows hierarchies web-based resources addressed via purls without resource requiring purl one purl sufficient serve top-level node hierarchy single target server new purl service uses type partial denote purl performs partial redirection partial redirections level url path violate common interpretations http 1.1 specification however handling url fragments across redirections standardized consensus yet emerged fragment identifiers indicate pointer specific information within resource designated following separator uris partial redirection presence fragment identifier problematic two conflicting interpretations possible fragment attached purl type partial purl service assume fragment meaning target url discard presumption resource changed location may also changed content thus invalidating fragments defined earlier bos suggested fragments retained passed target urls http redirections resulting 300 multiple choice 301 moved permanently 302 found 303 see responses unless designated target url already includes fragment identifier fragment identifier already present target url fragment original url abandoned unfortunately bos ’ suggestion failed navigate ietf standards track expired without work dubost et al resurrected bos ’ suggestions w3c note standard guidance absence standard makers web clients browsers generally failed follow bos ’ guidance starting purlz 1.0 series purl service implements partial redirections inclusive fragment identifiers writing fragments onto target urls attempt comply avoid problematic inconsistent behavior browser vendors
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Internet protocols
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rad750 rad750 radiation-hardened single board computer manufactured bae systems electronics intelligence support successor rad6000 rad750 use high radiation environments experienced board satellites spacecraft rad750 released 2001 first units launched space 2005 cpu 10.4 million transistors order magnitude rad6000 1.1 million manufactured using either 250 150 nm photolithography die area 130 mm core clock 110 200 mhz process 266 mips cpu include extended l2 cache improve performance cpu withstand 200,000 1,000,000 rads 2,000 10,000 gray temperature ranges –55 °c 125 °c requires 5 watts power standard rad750 single-board system cpu motherboard withstand 100,000 rads 1,000 gray temperature ranges –55 °c 70 °c requires 10 watts power rad750 system price comparable rad6000 us 200,000 per board per 2002 reference however customer program requirements quantities greatly affect final unit costs rad750 based powerpc 750 packaging logic functions completely compatible powerpc 7xx family term rad750 registered trademark bae systems information electronic systems integration inc 2010 reported 150 rad750s used variety spacecraft notable examples order launch date include
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Computer architecture
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microsoft mahjong microsoft mahjong formerly mahjong titans taipei computer game version mahjong solitaire published microsoft version titled mahjong titans developed oberon games included windows vista windows 7 except starter home basic editions takes advantage new graphical user interface gui windows vista includes features tile set background choices windows vista builds 5219 5231 5259 game known shanghai solitaire game make windows 8 however standalone version developed arkadium published microsoft studios downloaded windows store free charge older version game known taipei bundled microsoft entertainment pack 1 best microsoft entertainment pack version included 32767 possible configurations player choice six tile layouts cat turtle crab dragon fortress spider stylized portrayal respective object animal background image chosen five different options four tile sets including traditional mahjong tiles variations fuller coloring larger print alternative pastel tile set entirely different picture theme games entirely random always least one pair within five tiles topmost five tiles turtle layout often two pairs algorithm tile organization positions tiles mostly paired level otherwise matching tile available accessible position one level check ensure matching tile positioned beneath partner since every tile 3 partners enough prove game impossible solve newer version microsoft mahjong numerous layouts improved graphics sound internet features set daily challenges reward user badges completed xbox live integration
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Operating systems
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keith bergelt keith daniel bergelt born september 11 1958 american corporate executive former u.s. diplomat ceo open invention network responsible coordinating establishment maintenance patent ‘ ‘ no-fly ” zone around linux responsible safeguarding open competitive landscape key technology markets back-office transaction processing mission critical applications mobile communications/smartphones desktop computing bergelt born new york city raised village bayville new york north shore long island attended st. boniface martyr school sea cliff new york graduate locust valley high school high school classmate eileen chamberlain donahoe u.s ambassador un human rights council geneva switzerland bergelt holds degrees duke university ’ trinity college ab dedman school law southern methodist university jd edhec business school theseus mba addition studied management insead institut national des telecommunications int france economics technology policy university san francisco mclaren graduate school business upon graduation law school entered public service held diplomatic postings un new york city american embassy tokyo japan 12-year public service career also lived san francisco california washington d.c colleague tennis partner u.s. treasury secretary tim geithner time together american embassy tokyo early 1990s berlin wall fell wake collapse soviet union bergelt left government service embarked private sector career c-level strategy consulting focused innovation sri consulting menlo park ca sri consulting co-founded first strategy consulting practice area intellectual asset management major strategy consulting firm practice enabled companies develop strategies effectively build manage leverage value codified patents trademarks copyrights non-codified knowledge know-how etc intellectual capital licensing joint ventures donation abandonment creation spin-outs spin-ups spin-ins uniquely suited monetize corporate intangible assets bergelt brought motorola corporation schaumburg il establish serve general manager strategic intellectual asset management business unit focused distilling value motorola ’ intellectual property addition served director technology strategy tenure motorola following experience motorola coincident departure bob galvin motorola board directors recruited kelso company new york-based private equity firm manage ip strategy business development licensing ip-based portfolio company – cambridge display technology cdt – cambridge england establishing strategy licensing program cdt kelso bergelt engaged texas pacific group tpg full-time advisor technology investment group recruited principal financial group establish run first-of-its-kind ip fund financial services advisory firm focused transforming ip viable source collateral fourth lending vertical complement asset-based lending backed property/plant/equipment accounts receivable inventory tenure ceo paradox capital bergelt worked professionals banking ip law raise 350mm capital enabled paradox pioneer emergence ip viable asset class asset-based lending obviate necessity second lien lending ip-rich companies bergelt recruited ibm red hat sony nec philips novell serve ceo open invention network pro-competitive defensive patent management organization established enable freedom operate linux support democratization innovation occasioned open source projects linux 'bergelt chief executive officer open invention network since 2008 responsible defending integrity linux ecosystem previously bergelt criticized microsoft several times behavior towards open source community microsoft changed behavior embraced open source community signed open invention network cross license bergelt pleased company also interviewed linux.com 2008 linuxworld expo
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Operating systems
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steamroller microarchitecture amd steamroller family 15h microarchitecture developed amd amd apus succeeded piledriver beginning 2014 third-generation bulldozer-based microarchitecture steamroller apus continue use two-core modules predecessors aiming achieving greater levels parallelism steamroller still features two-core modules found bulldozer piledriver designs called clustered multi-thread cmt meaning one module equal dual-core processor focus steamroller greater parallelism improvements center independent instruction decoders core within module 25 maximum width dispatches per thread better instruction schedulers improved perceptron branch predictor larger smarter caches 30 fewer instruction cache misses branch misprediction rate reduced 20 dynamically resizable l2 cache micro-operations queue internal register resources improved memory controller amd estimated improvements increase instructions per cycle ipc 30 compared first-generation bulldozer core maintaining piledriver high clock rates decreased power consumption final result 9 single-threaded ipc improvement 18 multi-threaded ipc improvement piledriver steamroller microarchitecture cpus well graphics core next microarchitecture gpus paired together apu lines support features specified heterogeneous system architecture 2011 amd announced third-generation bulldozer-based line processors 2013 next generation bulldozer working title using 28 nm manufacturing process 21 september 2011 leaked amd slides indicated third generation bulldozer core codenamed steamroller january 2014 first kaveri apus became available starting may 2015 till march 2016 new apus launched kaveri-refresh codenamed godavari november 2013 amd confirmed would update fx series 2014 neither socket am3+ version receive steamroller version new socket amd server roadmaps 2014 showed however plans steamroller opteron products cancelled likely due poor energy efficiency achieved generation bulldozer architecture energy efficiency greatly increased following generation excavator exceeded jaguar performance per watt approximately doubled performance/watt steamroller example 20.74 pt/w vs 10.85 pt/w comparing similar mobile apus using rough arbitrary metrics
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Computer architecture
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mccumber cube 1991 john mccumber created model framework establishing evaluating information security information assurance programs known mccumber cube security model depicted three-dimensional rubik cube-like grid concept model developing information assurance systems organizations must consider interconnectedness different factors impact devise robust information assurance program one must consider security goals program see also goals relate specifically various states information reside system full range available security safeguards must considered design mccumber model helps one remember consider important design aspects without becoming focused one particular i.e. relying exclusively technical controls expense requisite policies end-user training per john mccumber website idea push back advance security art support structured methodology functions independent technology evolution basis methodology inter-relationship among confidentiality integrity availability storage transmission processing applying policy procedures human side technology
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Computer security
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apple push notification service apple push notification service commonly referred apple notification service apns platform notification service created apple inc. enables third party application developers send notification data applications installed apple devices notification information sent include badges sounds newsstand updates custom text alerts first launched ios 3 june 17 2009 apns support local applications later added mac os x api beginning release mac os x 10.7 lion support website notifications later added release mac os x 10.9 mavericks apple announced service june 9 2008 original stated release september however stated scott forstall ios 3.0 preview event march 17 2009 rollout delayed decision restructure apns scalability purposes due allegedly overwhelming response announcement apns events forstall stated push notifications better conserve battery background processes used pull technology receiving notifications apns first launched together ios 3.0 june 17 2009 release ios 5.0 included notification center adding support receiving reading local notifications single place apns also added api mac os x 10.7 lion developers could begin updating third-party applications start utilizing service support later improved os x 10.8 mountain lion introduction notification center ios 5.0 improvement allowed users manage read received notifications single location release os x 10.9 mavericks included safari 7.0 added support accepting receiving apns notifications websites user granted permission 2014 maximum size allowed notification payload sent binary interface increased 256 bytes 2 kilobytes december 2015 new http/2 provider api released apple effectively replacing now-legacy binary interface maximum notification payload size allowed using http/2 api 4 kilobytes october 22 2014 apple announced would cease support ssl 3.0 october 29 2014 due poodle attack gained public attention shortly date developers required use tls protocol send notification using apns
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Operating systems
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automated lip reading automated lip reading alr software technology developed speech recognition expert frank hubner video image person talking analysed software shapes made lips examined turned sounds sounds compared dictionary create matches words spoken technology used successfully analyse silent home movie footage adolf hitler taken eva braun bavarian retreat berghof video words included documentary titled hitler private world revealed studios 2006 source new technology catches hitler guard
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Computational linguistics
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kaby lake kaby lake intel codename processor microarchitecture intel announced august 30 2016 like preceding skylake kaby lake produced using 14 nanometer manufacturing process technology breaking intel previous tick–tock manufacturing design model kaby lake represents optimized step newer process-architecture-optimization model kaby lake began shipping manufacturers oems second quarter 2016 mobile chips started shipping kaby lake desktop chips officially launched january 2017 august 2017 intel announced kaby lake refresh kaby lake r marketed 8th generation mobile cpus breaking long cycle architectures matched corresponding generations cpus skylake anticipated succeeded 10 nanometer cannon lake announced july 2015 cannon lake delayed second half 2017 meantime intel released fourth 14 nm generation october 5 2017 named coffee lake kaby lake first intel platform lack official driver support versions windows older windows 10 furthermore windows update disabled windows 8.1 earlier although enthusiast-created modification released disabled check allowed continue work platform previous intel processors 8088 banias dothan conroe sandy bridge ivy bridge skylake kaby lake development led intel israeli team based haifa intel israel development centers manager ran senderovitz said started project thinking basic improvements previous generation began looking things differently lot innovation determination achieved major improvements added performance seventh generation chips improved 12 applications 19 internet use compared sixth generation chips third-party benchmarks confirm percentages far gaming concerned built improved 14 nm process 14ff+ kaby lake features faster cpu clock speeds clock speed changes higher turbo frequencies beyond process clock speed changes little cpu architecture changed skylake resulting identical ipc instructions per clock kaby lake features new graphics architecture improve performance 3d graphics 4k video playback adds native hdcp 2.2 support along fixed function decode h.264 hevc main main10/10-bit vp9 10-bit 8-bit video hardware encode supported h.264 hevc main10/10-bit vp9 8-bit video vp9 10-bit encode supported hardware opengl 4.6 opencl 2.1 supported kaby lake first core architecture support hyper-threading pentium-branded desktop cpu sku kaby lake also features first overclocking-enabled i3-branded cpu kaby lake features cpu core performance per mhz skylake features specific kaby lake include microsoft officially supports kaby lake computers running windows 10 per support policies windows update blocks updates installed kaby lake systems running versions older windows 10 support position intel provides chipset drivers windows 10 enthusiast-created modification released disabled windows update check allowed windows 8.1 earlier continue updated platform kaby lake critical flaw short loops may cause unpredictable system behavior issue fixed motherboard manufacturer releases bios update fix thermal design power tdp designed maximum heat generated chip running specific workload base clock single microarchitecture heat produced increases voltage frequency thermal design limit also limit maximum frequency processor however cpu testing binning allows products lower voltage/power particular frequency higher frequency within power limit desktop processors mobile processors features common desktop kaby lake cpus maximum pcie lanes 16 release date q1 2017 late 2016 reported intel working processor family codenamed “ kaby lake r ” r stands refresh august 21 2017 eighth generation mobile cpus announced first products released four kaby lake r processors 15w tdp marketing distinct previous generational changes core product line new generation coincided new microarchitecture intel stated 8th generation would based multiple microarchitectures including kaby lake coffee lake cannon lake maximum number pcie lanes 8 release date q1 2018 august 28 2018 intel announced refreshed lineup ultra low power mobile kaby lake cpus moniker amber lake
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Computer architecture
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yandex disk yandex.disk cloud service created yandex lets users store files “ cloud ” servers share others online service based syncing data different devices yandex.disk launched english june 2012 storage — users upload save files restrictions length time files stored files uploaded encrypted connection checked antivirus syncing — files synced user internet-enabled devices either web interface yandex.disk mobile/desktop application sharing — users share file download links others preview — built-in flash player lets people preview songs integration yandex services — lets people manage files yandex services yandex.mail yandex.narod sent received mail attachments automatically placed one folder easily searched webdav support — means files managed application supporting webdav protocol yandex.disk api used software program supporting webdav web version located inside yandex.mail “ files ” tab applications available following operating systems mobile version included part yandex.mail mobile app lets users view files yandex.disk upload files mobile device download files use offline email file download links yandex.disk api also supports webdav protocol allows third-party applications upload files yandex cloud storage service yandex.disk api makes easier sync info smartphones tablet pcs laptops desktop computers api lets developers yandex.disk api documentation released april 28 2012 service provided completely free charge everyone starts free allowance 10gb easily increased 512 mb increments referring others additional maximum 10 gb 20 gb total also additional storage paid monthly yearly basis choose enable device auto-uploads using yandex.disk app android ios granted additional 32 gb free storage increases maximum storage 10 gb 42 gb april 5 2012 – beta version service launched may 3 2012 – first api open source client launched may 24 2012 – flash player introduced web interface “ save disk ” button added shared file page allows users share files published others account june 26 2012 – english turkish versions available
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Distributed computing architecture
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off-side rule computer programming language said adhere off-side rule blocks language expressed indentation term coined peter j. landin offside rule football contrasted free-form languages notably curly-bracket programming languages indentation meaningful indent style matter convention code formatting peter j. landin article called next 700 programming languages defined off-side rule thus non-whitespace token left first token previous line taken start new declaration following example indentation blocks python colons part python language syntax readability necessary implement off-side rule python rule taken define boundaries statements rather declarations python also suspends off-side rule within brackets statement within brackets continues brackets match mismatch off-side rule implemented lexical analysis phase python increasing indentation results lexer outputting indent token decreasing indentation results lexer outputting dedent token tokens correspond opening brace codice_1 closing brace codice_2 languages use braces blocks means phrase grammar depend whether braces indentation used requires lexer hold state namely current indentation level thus detect changes indentation changes thus lexical grammar context-free – indent/dedent depend contextual information previous indentation level primary alternative delimiting blocks popularized c ignore whitespace mark blocks explicitly curly brackets i.e. codice_1 codice_2 delimiter allows freedom – developer might choose indent small pieces code like break continue statements – sloppily indented code might lead reader astray lisp s-expression based languages differentiate statements expressions parentheses enough control scoping statements within language curly bracket languages whitespace mostly ignored reader i.e. read function whitespace used separate tokens explicit structure lisp code allows perform automatic indentation acts visual cue human lisp readers another alternative block begin end explicit keywords example algol 60 descendant pascal blocks start keyword codice_5 end keyword codice_6 languages pascal means newlines important unlike curly brace languages indentation basic fortran blocks begin block name codice_7 end block name prepended codice_8 e.g. codice_9 fortran every block also unique block name adds additional level explicitness lengthy code algol 68 bourne shell sh bash similar ending block usually given name block written backward e.g. codice_10 starts switch statement spans matching codice_11 similarly conditionals codice_12 ... codice_13 ... codice_14 ... codice_15 ... codice_16 loops codice_17 ... codice_18 ... codice_19 algol68 codice_17 ... codice_18 ... codice_22 bash interesting variation made modula-2 pascal-like language away difference one multiline blocks allows block opener codice_1 codice_24 skipped function level block requiring block terminating token codice_2 codice_8 also fixes dangling else custom codice_6 token placed indentation level rest block giving blockstructure readable one advantage fortran approach improves readability long nested otherwise complex code group outdents closing brackets alone provide contextual cues blocks closed necessitating backtracking closer scrutiny debugging addition languages allow suffix end-like keywords improve cues codice_28 versus codice_29 however modern code editing applications often provide visual indicators features folding assist drawbacks
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Programming language topics
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ephemeral port ephemeral port short-lived transport protocol port internet protocol ip communications ephemeral ports allocated automatically predefined range ip stack software ephemeral port typically used transmission control protocol tcp user datagram protocol udp stream control transmission protocol sctp port assignment client end client–server communication well-known port server servers ephemeral ports may also used port assignment server end communication done continue communications client initially connected one server well-known service listening ports file transfer protocol ftp remote procedure call rpc applications two protocols behave manner note term server includes workstations running network services receive connections initiated clients e.g remote desktop protocol allocations temporary valid duration communication session completion timeout communication session ports become available reuse since ports used per request basis also called dynamic ports internet assigned numbers authority iana suggests range 49152 65535 2+2 2−1 dynamic private ports many linux kernels use port range 32768 61000 freebsd used iana port range since release 4.6 previous versions including berkeley software distribution bsd use ports 1024 5000 ephemeral ports microsoft windows operating systems xp use range 1025–5000 ephemeral ports default windows vista windows 7 server 2008 use iana range default windows server 2003 uses range 1025–5000 default microsoft security update ms08-037 2008 installed uses iana range default windows server 2008 exchange server 2007 installed default port range 1025–60000 addition default range versions windows since windows 2000 option specifying custom range anywhere within 1025–65535 certain server software used uses non ephemeral custom port ranges initiating connections needs ensured configuration custom port range ephemeral port range overlap
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Internet protocols
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