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nokia n8 nokia n8 touchscreen-based smartphone developed nokia announced 27 april 2010 nokia n8 first device run symbian^3 mobile operating system company flagship device year released 30 september 2010 nokia online store released markets around world 1 october 2010 n8 3.5-inch amoled display 16 gigabytes mass memory features 12-megapixel camera second time camera megapixel count used first one sony ericsson satio 2009 xenon flash like nokia n82 large 1/1.83 ” sensor size larger point-and-shoot cameras time also 720p hd video recording pentaband 3.5g radio fm transmitter among connectivity features hdmi output usb on-the-go wi-fi 802.11 b/g/n n8 important device nokia bid increasing competition smartphone industry revamped symbian^3 software also important device delayed several times pushing release date several months negative impact company despite mixed views symbian software n8 hardware build camera quality well received many calling best camera phone n8 would also become nokia last flagship device running symbian due nokia lumia 800 2011 ran windows phone software n8 symbian successor nokia 808 pureview appeared 2012 previous flagship phone nseries n97 criticised initial firmware issues anssi vanjoki nokia executive vice president markets said interview software quality control would better n97 n97 reception highly negative tarnished company image market n8 first device feature symbian^3 operating system initially scheduled second quarter 2010 n8 pushed back third quarter finally released 30 september 2010 due 'final amendments n8 became product customer pre-orders nokia history point release sales q4 2010 estimated almost 4 million previous nokia phone focus photography n86 8mp 8-megapixel sensor become available june 2009 n8 second nokia capacitive touchscreen following x6 first multi-touch nokia n8 dual charging options allowing charged standard-pin nokia charger micro-usb port nokia n8 battery compartment internally contained thus battery entirely straightforwardly removable replaceable users nonetheless although procedure endorsed nokia possible correct tool careful handling change battery. bl-4d 1200 mah lithium-ion battery n8 first nokia smartphone device run symbian^3 operating system 7 february 2012 nokia belle update available n8 nokia suite august year nokia also started roll nokia belle refresh update update brought new features symbian smartphone like html 5 web apps support new set home screen widgets software function n8 smartphone anna operating system update gave communicator support usually reserved e-series devices also new push notification api corresponding app proprietary web browser latest version 7.4.2.6 belle v.111.030.0609 official firmware including video-capturing feature complemented mini hdmi port located top side phone normally mirrors phone screen allows applications built-in video player nokia big screen app selected games output content resolutions 720p corresponding cable provided retail box regions nokia mobile tv headset provides dvb-h tv applications developed using nokia qt framework highlight capabilities nokia n8 camera nokia created short film commuter october 2010 directed mchenry brothers starring dev patel ed westwick charles dance pamela anderson seven-minute film shot entirely phone 720p camera spanish promotion phone also created short video featuring luminescent puppets called www.techfashy.com/2014/11/nokia-launches-their-first-android_18.html love knot phone also used film drums death wo n't long music video using cellscope technology nokia also released another film called dot marketed world smallest stop-motion animation character device also appeared popular showtime tv show dexter bbc tv series hustle well film also phone sarah lund uses third series killing .. asian countries promoted differently fictional character pier roxas nokia project gener8 young rubicam philippines also appeared gma talk show startalk promote device nokia shorts 2011 competition involved 8 short films shot nokia n8 winner splitscreen love story independent film olive first feature-length film 90 minutes made entirely cell phone uses nokia n8 along old fashioned video camera attachment 35 mm lens made exclusively device trick audience realizing made nokia n8
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Operating systems
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livedrive livedrive online cloud backup sync storage service owned j2 global company provides users unlimited backup space 2,000 gb sync storage livedrive enables users access data mobile phones tablets currently livedrive apps ios android windows macos chrome os livedrive founded late 2008 andrew michael another investor company nicholas cowell may 2009 three months product launched business offered £100 million buy-out company turned offer stating wanted build company october 2009 livedrive entered us market place via distribution agreement lifeboat distribution international speciality software distribution security application lifecycle virtualization network infrastructure products april 2011 livedrive created april fools video falsely stated company storing files paper using qr codes story picked several press sources true story including cbs money watch february 10 2014 livedrive purchased j2 global livedrive part j2 business cloud services division includes efax evoice fusemail campaigner keepitsafe shutting hundreds user accounts “ excessive bandwidth/storage ” livedrive reported august 2014 facing legal action discontented customers september 2010 livedrive added personal music movie streaming accounts gave users ability listen music collections watch movies remote computer transcoding handled livedrive company also gave users ftp access unlimited versioning
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Distributed computing architecture
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argus – audit record generation utilization system argus – audit record generation utilization system first implementation network flow monitoring ongoing open source network flow monitor project started carter bullard 1984 georgia tech developed cyber security carnegie mellon university early 1990s argus important contributor internet cyber security technology 30 years argus project focused developing aspects large scale network situational awareness network audit trail establishment support network operations netops performance security management motivated telco call detail record cdr argus attempts generate network metadata used perform large number network management tasks argus used many universities corporations government entities including us disa dod dhs ffrdcs gloriad top 100 internet security tool argus designed real-time situational awareness system data used track alarm alert wire-line network conditions data also used establish comprehensive audit network traffic described red book us dod ncsc-tg-005 supplementing traditional intrusion detection system ids based network security audit trail traditionally used historical network traffic measurement data network forensics network behavior anomaly detection nbad argus used extensively cybersecurity end-to-end performance analysis recently software-defined networking sdn research argus also topic network management standards development rmon 1995 ipfix 2001 argus composed advanced comprehensive network flow data generator argus monitor processes packets either capture files live packet data generates detailed network traffic flow status reports flows packet stream argus monitors network traffic data plane control plane management plane internet protocol ip traffic argus captures much packet dynamics semantics flow great deal data reduction store process inspect analyze large amounts network data efficiently argus provides reachability availability connectivity duration rate load good-put loss jitter retransmission data networks delay metrics network flows captures attributes available packet contents layer 2 addresses tunnel identifiers mpls gre ipsec etc ... protocol ids sap hop-count options l4 transport identification rtp detection host flow control indications etc ... argus implemented number packet dynamics metrics specifically designed cyber security argus detects human typing behavior flow particular interest key-stroke detection encrypted ssh tunnels argus generates producer consumer ratio pcr indicates whether network entity data producer and/or consumer important property evaluating potential node involved advanced persistent threat apt mediated exfiltration argus open source gpl project owned managed qosient llc ported operating systems many hardware accelerated platforms bivio pluribus arista tilera software portable many environments little modifications performance auditing entire enterprise internet activity accomplished using modest computing resources
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Computer security
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playstation 2 sales sony playstation 2 best-selling video game console time console sold slightly 500,000 units first day november 2000 marked industry record fastest-selling game console sony planned ship 100,000 units per week remainder year total 1.3 million end year planned ship three million units end march following year sony shipped 10 million consoles north america may 2002 holiday 2002 sales strong 8.5 million units november december 24 previous year sony expected shipments 2003 slip previous years sony projected shipments 20 million versus 22.5 year sony shipped 60 million units september 2003 26.4 million units went north america 19.4 million europe vast majority remaining 14.2 went japan 2004 although console took hit holiday 2003 sales previous year lifetime sales reached 70 million november 29 2005 playstation 2 became fastest game console reach 100 million units shipped accomplishing feat within 5 years 9 months launch achievement occurred faster predecessor playstation took 9 years 6 months reach benchmark europe ps2 sold 6 million units 2006 3.8 million 2007 according estimates ea 2007 ps2 sold 3.97 million units us according npd group 816,419 units japan according enterbrain 2008 ps2 sold 480,664 units japan according enterbrain october 2008 system sold 21 million units japan 150 million units ps2 hardware sold worldwide end 2010 although gameinformer noted units sold retail companies playstation 2 shipments japan ended december 28 2012 week later january 4 2013 sony computer entertainment formally discontinued console last week availability japan december 24 december 30 2012 playstation 2 sold 2,078 units country 928 units week remarkably playstation 2 managed sell better japan week xbox 360 1,986 units well nintendo ds 704 units ps2 sold 158 million units worldwide january 2013 europe sold 56 million units january 2013 according sony computer entertainment europe north america sold 53.65 million units january 2013 japan ps2 sold 23.18 million units january 2013 according famitsu /enterbrain
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Computer architecture
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camino web browser camino spanish word meaning path discontinued free open source gui-based web browser based mozilla gecko layout engine specifically designed os x operating system place xul-based user interface used mozilla-based applications camino used mac-native cocoa apis may 30 2013 camino project announced browser longer developed camino aim integrate well possible os x used aqua user interface integrated number os x services features keychain password management bonjour scanning available bookmarks across local network notable features included integrated pop-up blocker ad blocker tabbed browsing included overview feature allowing tabs viewed pages browser developed camino project community organization mike pinkerton technical lead camino project since dave hyatt moved safari team apple inc. mid-2002 late 2001 mike pinkerton vidur apparao started project within netscape prove gecko could embedded cocoa application early 2002 dave hyatt one co-creators firefox called phoenix joined team built chimera small lightweight browser wrapper around work chimera mythological beast parts taken various animals new browser represented early example carbon/c++ code interacting cocoa/objective-c code name must seemed apt first downloadable build chimera 0.1 released february 13 2002 early releases became popular due fast page-loading speeds compared then-dominant mac browser microsoft internet explorer version 5 omnigroup omniweb used cocoa text system rendering engine hyatt hired apple computer mid-2002 start work would become safari meanwhile chimera developers got small team together within netscape dedicated development qa put together netscape-branded technology preview january 2003 macworld conference however two days show aol management decided abandon entire project despite setback skeleton crew qa developers released camino 0.7 march 3 2003 name changed chimera camino legal reasons roots greek mythology chimera popular choice name hypermedia systems one first graphical web browsers called chimera researchers university california irvine also developed complete hypermedia system name spanish path road el camino real aka royal road name chosen continue navigator motif version 0.7 primarily netscape-driven release kept afloat end open source version 0.8 according lead developer pinkerton triumph open source open process people around world helped patches qa bug triage localization artwork evangelism march 2005 camino web site moved mozilla foundation domain mozilla.org camino project domain caminobrowser.org september 2005 pinkerton accepted position google worked closely google firefox team continued work camino twenty percent time camino 1.0 released february 14 2006 first browser mozilla family appear universal binary thanks largely efforts mark mentovai another camino developers camino 2.0 released november 18 2009 introduced many new interface features browser including movable tabs tab preview first camino release acid2-compliant release camino 2.1 2011 developers announced plans transition webkit future versions mozilla dropped support gecko embedding final release 2.1.2 released march 14 2012 may 30 2013 stuart morgan announced camino blog camino reached end longer developed camino 2.0 released november 18 2009 introduced many new interface features browser including moveable tabs tab preview first camino release acid2-compliant current release 2.1.2 scores 99/100 acid3 test camino current html5 support via html5 test standards testbed limited camino 2.1.2 available following languages
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Internet protocols
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radius remote authentication dial-in user service radius networking protocol operating port 1812 provides centralized authentication authorization accounting aaa triple management users connect use network service radius developed livingston enterprises inc. 1991 access server authentication accounting protocol later brought internet engineering task force ietf standards broad support ubiquitous nature radius protocol often used internet service providers isps enterprises manage access internet internal networks wireless networks integrated e-mail services networks may incorporate modems digital subscriber line dsl access points virtual private networks vpns network ports web servers etc radius client/server protocol runs application layer use either tcp udp transport network access servers gateways control access network usually contain radius client component communicates radius server radius often back-end choice 802.1x authentication well radius server usually background process running unix microsoft windows server radius aaa protocol manages network access aaa stands authentication authorization accounting radius uses two packet types manage full aaa process access-request manages authentication authorization accounting-request manages accounting authentication authorization defined rfc 2865 accounting described rfc 2866 user machine sends request network access server nas gain access particular network resource using access credentials credentials passed nas device via link-layer protocol—for example point-to-point protocol ppp case many dialup dsl providers posted https secure web form turn nas sends radius access request message radius server requesting authorization grant access via radius protocol request includes access credentials typically form username password security certificate provided user additionally request may contain information nas knows user network address phone number information regarding user physical point attachment nas radius server checks information correct using authentication schemes pap chap eap user proof identification verified along optionally information related request user network address phone number account status specific network service access privileges historically radius servers checked user information locally stored flat file database modern radius servers refer external sources—commonly sql kerberos ldap active directory servers—to verify user credentials radius server returns one three responses nas 1 access reject 2 access challenge 3 access accept three radius responses may include reply-message attribute may give reason rejection prompt challenge welcome message accept text attribute passed user return web page authorization attributes conveyed nas stipulating terms access granted example following authorization attributes may included access-accept client configured use radius user client presents authentication information client might customizable login prompt user expected enter username password alternatively user might use link framing protocol point-to-point protocol ppp authentication packets carry information client obtained information may choose authenticate using radius client creates access- request containing attributes user name user password id client port id user accessing password present hidden using method based rsa message digest algorithm md5 accounting described rfc 2866 network access granted user nas accounting start radius accounting request packet containing acct-status-type attribute value start sent nas radius server signal start user network access start records typically contain user identification network address point attachment unique session identifier periodically interim update records radius accounting request packet containing acct-status-type attribute value interim-update may sent nas radius server update status active session interim records typically convey current session duration information current data usage finally user network access closed nas issues final accounting stop record radius accounting request packet containing acct-status-type attribute value stop radius server providing information final usage terms time packets transferred data transferred reason disconnect information related user network access typically client sends accounting-request packets receives accounting-response acknowledgement using retry interval primary purpose data user billed accordingly data also commonly used statistical purposes general network monitoring radius commonly used facilitate roaming isps example radius facilitates use realms identify radius server forward aaa requests processing realm commonly appended user user name delimited sign resembling email address domain name known postfix notation realm another common usage prefix notation involves prepending realm username using '\ delimiter modern radius servers allow character used realm delimiter although practice '\ usually used realms also compounded using prefix postfix notation allow complicated roaming scenarios example somedomain.com\username anotherdomain.com could valid username two realms although realms often resemble domains important note realms fact arbitrary text need contain real domain names realm formats standardized rfc 4282 defines network access identifier nai form 'user realm specification 'realm portion required domain name however practice always followed rfc 7542 replaced rfc 4282 may 2015 radius server receives aaa request user name containing realm server reference table configured realms realm known server proxy request configured home server domain behavior proxying server regarding removal realm request stripping configuration-dependent servers addition proxying server configured add remove rewrite aaa requests proxied time proxy chaining possible radius authentication/authorization accounting packets usually routed nas device home server series proxies advantages using proxy chains include scalability improvements policy implementations capability adjustments roaming scenarios nas proxies home server could typically managed different administrative entities hence trust factor among proxies gains significance inter-domain applications absence end end security radius adds criticality trust among proxies involved proxy chains explained roaming radius exposes users various security privacy concerns generally roaming partners establish secure tunnel radius servers ensure users credentials intercepted proxied across internet concern md5 hash built radius considered insecure radius packet data format shown right fields transmitted left right starting code identifier length authenticator attributes radius codes decimal assigned follows identifier field aids matching requests replies length field indicates length entire radius packet including code identifier length authenticator optional attribute fields authenticator used authenticate reply radius server used encrypting passwords length 16 bytes radius attribute value pairs avp carry data request response authentication authorization accounting transactions length radius packet used determine end avps radius extensible many vendors radius hardware software implement variants using vendor-specific attributes vsas microsoft published vsas vsa definitions many companies remain proprietary and/or ad-hoc nonetheless many vsa dictionaries found downloading source code open source radius implementations example freeradius openradius radius protocol transmits obfuscated passwords using shared secret md5 hashing algorithm particular implementation provides weak protection user credentials additional protection ipsec tunnels physically secured data-center networks used protect radius traffic nas device radius server additionally user security credentials part protected radius yet user-specific attributes tunnel-group ids vlan memberships passed radius may considered sensitive helpful attacker private sufficient identify individual client information well radsec protocol claims solve aforementioned security issues dial-up customers used nsfnet request proposal sent merit network 1991 consolidate various proprietary authentication authorization accounting systems among early respondents livingston enterprises early version radius written meeting early radius server installed unix operating system livingston enterprises acquired lucent together merit steps taken gain industry acceptance radius protocol companies offered radius server charge radius 1997 published rfc 2058 rfc 2059 current versions rfc 2865 rfc 2866 original radius standard specified radius stateless run user datagram protocol udp authentication envisaged radius support password authentication protocol pap challenge-handshake authentication protocol chap point-to-point protocol passwords hidden taking md5 hash packet shared secret xoring hash password original radius also provided 50 attribute value pairs possibility vendors configure pairs choice hop-by-hop security model rather end-to-end encryption meant several proxy radius servers use every server must examine perform logic pass data request exposes data passwords certificates every hop radius servers also ability stop access resources authorisation issued subsequent standards rfc 3576 successor rfc 5176 allowed radius servers dynamically change users authorization disconnect user entirely several commercial open-source radius servers exist features vary look users text files ldap servers various databases etc accounting records written text files various databases forwarded external servers etc snmp often used remote monitoring keep-alive checking radius server radius proxy servers used centralized administration rewrite radius packets fly security reasons convert vendor dialects diameter protocol intended replacement radius authentication authorization accounting aaa protocols use-cases two protocols since diverged diameter largely used 3g space radius used elsewhere one largest barriers diameter replace radius switches access points typically implement radius diameter diameter uses sctp tcp radius typically uses udp transport layer 2012 radius also use tcp transport layer tls security radius protocol currently defined following ietf rfc documents
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Internet protocols
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flockdb flockdb open-source distributed fault-tolerant graph database managing wide shallow network graphs initially used twitter store relationships users e.g followings favorites flockdb differs graph databases e.g neo4j designed multi-hop graph traversal rather rapid set operations unlike primary use-case redis sets since still process packaged outside twitter use code still rough hence stable release available yet flockdb posted github shortly twitter released gizzard framework uses query flockdb distributed datastore database licensed apache license
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Computer architecture
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ccso nameserver ccso name-server ph protocol early form database search internet common form used look information telephone numbers email addresses today service largely replaced ldap used mainly early-to-middle 1990s name-server developed steve dorner university illinois urbana–champaign university computing communications services office ccso also exists outlook plugin standalone application known outlookph name-server directories frequently organized gopher hierarchies tools ph qi two components system ph client queried qi server ph protocol formally defined september 1998 however memo issued time references prior use unspecified period time date defines sixteen keywords used server side define record properties also defines clients access records server responses server give ph server communication takes place tcp port 105 commands response initially assumed us-ascii encoding historical reasons unless client explicitly asks 8-bit iso-8859-1 encoding result characters 0x20 0x7e initially sent server raw form characters present entries escaped using defined quoted-printable encoding initial request client text base keyword optionally followed one parameters defined server responds request following example response status request provided rfc memo command defined memo consists keyword followed needed one parameters key words separated spaces tabs end line line must terminated cr+lf style following commands command takes parameters simply asks server report status returns information server version mail domain contact password issues authentication methods list available entry fields server specified name names causes server log specified information current user id without login sets specified option server value used without parameters lists current server settings actual login/logout commands server alias must users ph alias logging allows user change entry view certain fields flag restricted access client normally uses one send password information login command sent one recognized server end session command closing connection distributed nameserver backed flat file database early 1990s indiana university software developer larry hughes implemented version qi called phd written perl backed relational database code distributed open-source license several years prior university transition ldap
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Internet protocols
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orthogonality programming computer programming orthogonality means operations change one thing without affecting others term most-frequently used regarding assembly instruction sets orthogonal instruction set orthogonality programming language means relatively small set primitive constructs combined relatively small number ways build control data structures language associated simplicity orthogonal design fewer exceptions makes easier learn read write programs programming language meaning orthogonal feature independent context key parameters symmetry consistency example pointer orthogonal concept example ibm mainframe vax highlights concept ibm mainframe two different instructions adding contents register memory cell another register statements shown first case contents codice_1 added contents memory cell result stored codice_1 second case contents codice_1 added contents another register codice_4 result stored codice_1 contrast set statements vax one statement addition case two operands codice_6 codice_7 registers memory cells combination instruction adds contents codice_6 contents codice_7 storing result codice_6 vax ’ instruction addition orthogonal instructions provided ibm hence easier programmer remember use one provided vax design c language may examined perspective orthogonality c language somewhat inconsistent treatment concepts language structure making difficult user learn use language examples exceptions follow though concept first applied programming language orthogonality since become recognized valuable feature design apis even user interfaces small set composable primitive operations without surprising cross-linkages valuable leading systems easier explain less frustrating use
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Programming language topics
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simplelinux simplelinux linux distribution uses lzma compression compress system files project started 2007 group malaysian developers simplelinux slackware-based distribution comes live cd persistence version installed medium simplelinux comes multi-tasking operating system runs x window k desktop environment used primary graphical user interface current version k desktop environment used simplelinux kde 3.5 stable extended use compiz fusion also integrated newest simplelinux version simplelinux uses slackpkg install remove upgrade packages network moreover simplelinux provides optional lzm packages official repository applications provided repository compressed lzma
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Computer architecture
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kexec kexec abbreviated kernel execution analogous unix/linux kernel call exec mechanism linux kernel allows booting new kernel currently running one essentially kexec skips bootloader stage hardware initialization phase performed system firmware bios uefi directly loads new kernel main memory starts executing immediately avoids long times associated full reboot help systems meet high-availability requirements minimizing downtime feasible implementing mechanism kexec raises two major challenges support allowing signed kernels booted kexec merged version 3.17 linux kernel mainline released october 5 2014 disallows root user load arbitrary code via kexec execute complementing uefi secure boot in-kernel security mechanisms ensuring signed linux kernel modules inserted running kernel
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Operating systems
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ninja jajamaru-kun released nintendo japanese virtual console december 26 2006 pal regions september 21 2007 part ninja week hanabi festival promotion released north american virtual console october 22 2007 first time game made release outside japan respective regions primary inspiration behind robot ninja haggleman 8-bit style game retro game challenge nintendo ds game stars brother ninja-kun ninja-kid princess sakura kidnapped damazu-dayuu ninja-kun away journey task falls young jajamaru-kun game player starts three lives run jump throw shurikens game divided stages four floors eight ghost-like enemies japanese folklore names displayed stage begins sakura-hime damazu placed unreachable top screen enemies use various projectiles one cause player lose life jajamaru-kun lands top enemy simply temporarily stunned vice versa enemy defeated offscreen spirit appear ascend top screen collected disappeared receive points vary depending enemy among eight enemies one top floor tougher beat others player need careful deal sakura sometimes drop petals player collect damazu sometimes run around dropping bombs advance next stage player must defeat eight enemies using shurikens bricks yield items include three types power-ups collected gamapa-kun giant frog summoned jajamaru-kun riding completely invincible able eat enemies three sakura petals collected player go bonus stage jajamaru-kun bottom damazu top damazu drops bombs player throws shurikens upward player manages hit damazu bonus points awarded jajamaru-kun hit bomb goes next stage
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Computer architecture
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transaction management executive transaction management executive tmx ncr corporation proprietary transaction processing system running ncr tower 5000-series systems based motorola 680xx cpus system used mainly financial institutions 1980s 1990s basic features tmx operating system listed ncr tower 5000 systems also capable running unix svr3 version
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Operating systems
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spelunker video game originally released micrographic image atari 8-bit family 1983 game later ported commodore 64 re-released broderbund 1984 european publishing rights licensed ariolasoft arcade version followed 1985 game released nintendo entertainment system december 6 1985 japan september 1987 north america msx 1986 sequel released arcades nes september 18 1987 called irem japan player must walk jump increasingly challenging parts cave working finite supply fresh air could replenished various points cave hazards include bats drop deadly guano player ghost haunting cave appearing randomly attempting take player shadow world player character send blast air push ghost away however renders player character immobile seconds thus vulnerable dangers depleting air supply objects collect include sticks dynamite flares keys precise positioning jumping play key factors successfully completing game cave spelunker divided six levels although levels connect seamlessly forming one large map game clearly signals level change certain points showing name next level giving player bonus consisting extra life varying number points splash screen game original atari features excerpt modest mussorgsky pictures exhibition background music versions game including atari re-release feature different title theme nes msx versions additional music gameplay computer gaming world 1985 called spelunker thoroughly enjoyable game ... class act game re-released virtual console north america march 17 2008 europe september 5 2008 wii regions june 6 2013 wii u north america june 27 2013 nintendo 3ds sony computer entertainment japan released spelunker hd playstation 3 downloadable game playstation network store received playstation store best sales award 2009 sony computer entertainment japan game remake nes port high definition graphics 100 levels 10 large caves 10 levels 2015 square enix released free-to-play sequel titled spelunker world playstation 4 playstation vita 2017 new title based spelunker world announced nintendo switch released april 20 2017 japan later released worldwide spelunker party october 19 2017 although spelunker party released physically japan worldwide release digital-only 2016 collaboration happened spelunker neptunia series resulted unlockable minigame mode called neplunker megadimension neptunia vii consists two special dungeons mixes normal gameplay spelunker gameplay mini-game became notorious players due normal controls game suited platforming lack proper tutorial led many players experiencing unintentional deaths game returns series viir playstation vr-compatible remake playstation 4
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Computer architecture
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batterymax idle detection batterymax idle detection system used computer power management operating system control developed digital research inc. european development centre edc hungerford uk created address new genre portable personal computers laptops ran battery power also integral part novell palmdos 1.0 operating system tailored early palmtops 1992 power saving laptop computers traditionally relied hardware inactivity timers determine whether computer idle would typically take several minutes computer could identify idle behavior switch lower power consumption state monitoring software applications within operating system batterymax able reduce time taken detect idle behavior minutes microseconds moreover switch power states around 18 times second user keystrokes technique named dynamic idle detection includes halting stopping cpu periods microseconds hardware event occurs restart dr dos 5.0 first personal computer operating system incorporate idle detection system power management invented british engineers roger gross john p. constant august 1989 us patent describing idle detection system filed 9 march 1990 granted 11 october 1994 despite taking early lead protection patent batterymax enjoy significant commercial success sidelined disarray followed integration digital research novell inc. 1991 1992 three years invention software power management operating system control became ubiquitous following launch advanced power management apm microsoft intel batterymax uses technique dynamic idle detection provide power savings detecting application whether idle switching power states entering low power mode therefore extending battery life product batterymax employs layered model detection software encapsulated dos character device driver called idle contains hardware-dependent code support dynamic idle detection either linked dr-dos operating system bios loaded dynamically using config.sys device directive overloading built-in default driver versions dr-dos since version 5.0 contained dynamic idle detection support inside operating system kernel operating system believes application idle calls idle bios/driver layer executes custom code written computer manufacturer third parties verify request switch power states using device driver concept batterymax integrated hardware-related power management facilities might provided underlying hardware including interfacing apm acpi system bioses power states computer dependent vary manufacturer manufacturer power savings made number ways including slowing/stopping processor clock speed shutting power complete sub-systems switching power states codice_1 driver uses available hardware assistance detect application accessing components system example application may polling serial port updating graphics screen case device driver determines application fact idle overrides kernel call switch power states passing information back layers allowing application execution resume application idle waiting external event occur example keystroke mouse movement fixed amount time pass dr-dos kernel monitors dos api calls building profile applications behavior certain combinations api calls suggest application idle codice_1 driver able make subtle distinction program genuinely idle instance one polling keyboard tight loop one active also polling keyboard test abort key pressed driver makes distinction monitoring time taken go idle time within specified period driver assumes program idle e.g polling tight loop key pressed time outside specified limit driver assumes processing occurred polling keyboard allows application execution resume without switching power states local variable idle_cntdn specifies time actual time taken go idle compared value variable dynamically calculated initialization recalculated periodically idle detection technique first used improve multi-tasking single-tasking dos applications digital research multi-tasking/multi-user concurrent dos 386 cdos386 operating system programs written single-tasking operating systems ms-dos/pc dos go endless loops interrupted example waiting user press key whilst problem process waiting run wastes valuable processor time could used programs multi-tasking/multi-user environment like cdos386 applications designed multi-tasking environment use api calls sleep idle period time normal dos applications idle detection must used concurrent dos 386 release included idle detection function operating system kernel monitored dos api calls determine whether application useful work fact idle idle process suspended allowing dispatcher schedule another process execution batterymax idle detection patent played important role alleged patent infringement relating software power management operating system control 15 may 2009 st. clair intellectual property consultants inc. filed civil action 09-354 united states district court d. delaware defendants acer inc. dell inc. gateway inc. lenovo group inc. 18 september 2009 filed civil action 09-704 apple inc. toshiba corporation inc actions alleged infringement several u.s. patents owned relating software power management operating system control st. clair asserted henry fung invented software power management operating system control alleged companies infringed st. clair patents therefore owed st. clair royalty payments microsoft intervened behalf defendants filed declaratory judgment st. clair 7 april 2010 seeking judgments non-infringement invalidity fung patents d.i 1 c.a 10-282 intel corporation filed intervention behalf defendants granted 4 june 2010 d.i 178 c.a 09-354 seattle law firm perkins coie llp acting defendants discovered batterymax gross idle detection patent prior art search gross patent earlier priority date fung patents proven would undermine st. clair case 28 february 2011 gross hired intel subject matter expert provide expert witness testimony defendants case gross provided evidence expert report fung invented software power management operating system control sited idle detection patent existence batterymax proof st clair filed motion exclude opinions concerning batterymax attempt gross expert report dismissed 29 march 2013 district court denied st. clair motion declaring gross testimony defendants admissible stating court agrees defendants sufficient corroborating evidence batterymax available public prior fung patents priority date court concludes even batterymax predate fung patents mr gross testimony … would relevant helpful fact finder obviousness inquiry ”
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Operating systems
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working directory computing working directory process directory hierarchical file system dynamically associated process sometimes called current working directory cwd e.g bsd function current directory process refers file using simple file name relative path opposed file designated full path root directory reference interpreted relative current working directory process example process working directory /rabbit-shoes asks create file foo.txt end creating file /rabbit-shoes/foo.txt computer file systems every directory entry usually named points directory dos unix command shells well microsoft windows command line interpreters cmd.exe windows powershell working directory changed using cd chdir commands unix shells pwd command outputs full pathname current working directory equivalent command dos windows cd chdir without arguments whereas unix cd used without arguments takes user back his/her home directory environment variable pwd unix/linux shells pseudo-environment variables cd windows command.com cmd.exe os/2 dos _cwd _cwds _cwp _cwps 4dos 4os2 4nt etc used scripts one need start external program microsoft windows file shortcuts ability store working directory command.com dr-dos 7.02 higher provides echos variant echo command omitting terminating linefeed used create temporary batchjob storing current directory environment variable like cd later use example alternatively multiuser dos dr-dos 7.02 higher various internal external commands support parameter /b batch modifies output commands become suitable direct command line input redirecting batch file usage parameter commands using input another command chdir would issue directory path like codice_1 command like chdir /b would issue codice_2 instead chdir /b retdir.bat would create temporary batchjob allowing return directory later current working directory also displayed p token codice_3 command keep prompt short even inside deep subdirectory structures dr-dos 7.07 command.com supports w token display deepest subdirectory level default prompt p g would result f.e codice_4 codice_5 prompt n w g would instead yield codice_6 codice_7 respectively similar facility using w w added 4dos well dos absolute paths current working directories volumes internaly stored array-like data structure called current directory structure cds gets dynamically allocated boot time hold necessary number slots drives defined lastdrive structure imposes length-limit 66 characters full path current working directory thus implicitly also limits maximum possible depth subdirectories dos plus older issues dr dos dr dos 6.0 1991 limitation due implementation using dos emulation top concurrent dos- thus cp/m-86- derived kernel internally organized subdirectories relative links parent directories instead absolute paths since palmdos dr dos 6.0 since 1992 higher switched use cds maximum compatibility dos programs well faced limitations present doses programming languages provide interface file system functions operating system including ability set change working directory program c language posix function codice_8 effects system call changes working directory argument text string path new directory either absolute relative old one available called process set working directory function languages visual basic usually spelled codice_9 unlike windows api posix c function neither java programming language java virtual machine supports codice_8 directly change request remained open decade team responsible java considered alternatives though 2008 request denied limited support introduced affecting first codice_11 later codice_12
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Computer file systems
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imieliński-lipski algebra imieliński-lipski algebras extension relational algebra onto tables different types null values used operate relations incomplete information imieliński-lipski algebras defined satisfy precise conditions semantically meaningful extension usual relational operators projection selection union join operators relations operators relations various kinds null values conditions require system safe sense incorrect conclusion derivable using specified subset f relational operators complete sense valid conclusions expressible relational expressions using operators f fact derivable system example well known 3-valued logic approach deal null values supported treatment nulls values sql complete see ullman book show let take sql query q sql query q return empty set results 3-valued semantics currently adopted variants sql case sql null never equal constant – case neither “ spring ” “ fall ” “ winter ” winter semester school codice_1 evaluate maybe codice_2 disjunction maybe maybe evaluates maybe true thus igor part answer course neither rohit igor returned answer indeed regardless semester igor took networks class matter unknown value null selection condition true “ igor ” missed sql sql answer ’ complete according completeness requirements specified tomasz imieliński witold lipski 'incomplete information relational databases also argued 3-valued logic true false maybe never provide guarantee complete answer tables incomplete information three algebras satisfy conditions safety completeness defined imielinski-lipski algebras codd-tables algebra v-tables algebra conditional tables c-tables algebra codd-tables algebra based usual codd singe null values table example codd-table codd-table algebra supports projection positive selections also demonstrated il84 possible correctly extend relational operators codd-tables example basic operation join extendable codd-tables possible define selections boolean conditions involving negation preserve completeness example queries like query q supported order able extend relational operators expressive form null value representation needed tables called v-table v-tables algebra based many different marked null values variables allowed appear table v-tables allow show value may unknown different tuples example table gaurav igor order unknown beer two unknown bars may may different – remain unknown gaurav jane frequent unknown bad y1 thus instead one null value use indexed variables skolem constants v-tables algebra shown correctly support projection positive selection negation occurring selection condition union renaming attributes allows processing arbitrary conjunctive queries desirable property enjoyed v-table algebra relational operators tables performed exactly way case usual relations example conditional table c-table shown additional column “ con ” boolean condition involving variables null values – v-tables following table c-table conditional tables algebra mainly theoretical interest supports projection selection union join renaming closed world assumption also handle operator difference thus support relational operators imieliński-lipski algebras introduced tomasz imieliński witold lipski jr. 'incomplete information relational databases
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Databases
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oulu university secure programming group oulu university secure programming group ouspg research group university oulu studies evaluates develops methods implementing testing application system software order prevent discover eliminate implementation level security vulnerabilities pro-active fashion focus implementation level security issues software security testing ouspg active independent academic research group computer engineering laboratory department electrical information engineering university oulu since summer 1996 ouspg known participation protocol implementation security testing called robustness testing using protos mini-simulation method protos co-operated project vtt number industrial partners project developed different approaches testing implementations protocols using black-box i.e functional testing methods goal support pro-active elimination faults information security implications promote awareness issues develop methods support customer driven evaluation acceptance testing implementations improving security robustness products attempted supporting development process notable result protos project result c06-snmp test suite discovered multiple vulnerabilities snmp work done protos continued protos-genome applies automatic structure inference combined domain specific reasoning capabilities enable automated black-box program robustness testing tools without prior knowledge protocol grammar work resulted large number vulnerabilities found archive file antivirus products group produced two spin-off companies codenomicon continues work protos clarified networks work frontier
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Computer security
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credential management credential management also referred credential management system cms established form software used issuing managing credentials part public key infrastructure pki cms software used governments enterprises issuing strong two-factor authentication 2fa employees citizens cms integrates components pki provide one joined-up solution departments issue manage credentials wide selection devices including smart cards usb keys smartphones laptops desktop computers credential management also proposed application programming interface api development world wide web consortium standardizing aspects password managers used web user agents web browsers applications create store use modify username password combinations logins addition management federated credentials single sign-on tokens user agents api developed w3c web application security working group working draft status since april 2016 recommendation-track proposal expected become accepted standard may undergo significant changes occurs credential management api already extended webauthn web authentication proposal reached candidate recommendation status april 2018 adds ability handle public-key authentication common modern web browsers able store automatically enter usernames passwords website logins though often used suboptimal heuristics guessing form fields data supposed filled/stored resulting inconsistent sometimes faulty behavior browsers also trouble filling login forms federated identities user connecting website uses account third-party web service like facebook google twitter authenticate provide identity information credential management specification also aims streamline process changing passwords locally stored password client updated time modified server google chrome included support credential management since version 51 released may 2016 opera included support since version 44 released april 2017 mozilla firefox includes subset api support webauthn since version 60 released may 2018 august 2017 working draft user agents supporting credential management api must implement credential store persistent storage credential objects also include credential chooser allow users interact objects allow deny use logins credentials ideally name favicon associated perhaps along related information help distinguish website service used well ability differentiate credentials multiple accounts site api defines four main javascript methods expose codice_1 interface codice_2 codice_3 codice_4 codice_5 also specifies top-level codice_6 interface object descendant codice_7 codice_8 object types webauthn also defines codice_9 interface object api available user agent connected secure https website browsers still implement auto-filling login information non-secure sites must allow sites benefit automation api provides since could lead accidental exposure passwords credentials addition api access allowed top-level windows within codice_10 elements nested browsing contexts codice_2 method used constructing credential objects memory codice_12 triggers writing object credential store following successful login codice_13 requests potentially relevant credentials storage may presented user credential chooser retrieval requests made user agents required prompt user authorization default though user interface allow flag set allows silent authorization without presenting prompt website reset flag codice_14 method recommended use logging
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Computer security
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basic telecommunications access method basic telecommunications access method btam low-level programming interface specified ibm use ibm system/360 start-stop binary synchronous telecommunications terminals later ibm specified higher-level interfaces qtam tcam btam superseded vtam systems network architecture sna devices btam continued supported later iterations system architecture ibm finally withdrew support 2000 btam requires application program transaction processing system handle almost every detail protocol harder using higher-layer protocol permits interfacing non-standard devices non-standard ways btam access method interactively communicating remote terminals usually connected front end processor 270x although support local channel-attached 3270 terminals included btam dynamically builds channel command words ccws reading writing polling terminals deals specific responses terminals according success failure communication channel btam key component ibm early transaction processing systems mtcs cics ims underpinned rise online transaction processing many large commercial banks insurance companies unusual btam later developed access methods vtam co-exist supporting different devices simultaneously transaction processing system material section taken ibm system/360 operating system basic telecommunications access method gc30-2004-6 btam programming requires detailed knowledge characteristics specific terminals used dcb macro used define communications line group br codice_1 br codice_2 coded specify binary synchronous bisync line many operands specify unique characteristics attached terminals terminal list specified codice_3 macro identifies terminals attached line macro specifies line characteristics—start-stop bisync point-to-point multipoint leased line dial — type polling required— wrap around open polling characters telephone number used identify specific remote device line coded codice_4 macro used modify information specific device list execution wrap-around polling list cause device list polled sequentially channel response received reduces load cpu continuous polling programmer specify buffer pool data structure used hold messages transmitted terminals btam construct pool automatically programmer construct pool various ways build macro format pool static dynamic storage previously acquired codice_5 macro acquire format storage automatically read operations btam automatically obtain one buffers pool store received message write operation programmer needs code codice_6 obtain number buffers necessary build output message either case codice_7 used free buffers completion read write tha codice_8 codice_9 include translation tables translate non ebcdic character codes standard os/360 codice_10 codice_11 macros used initiate terminate processing btam line codice_12 macro reinitialize line whatever reason failed open successfully btam provides large number options codice_13 codice_14 macros depending line terminal types current status operations read initial reset read conversational read repeat write initial write break write continue transparent specified codes codice_15 read initial read write operation executed asynchronously channel following read write codice_16 codice_17 macro required wait completion retrieve ending status codice_18 macro cancels outstanding read and/or stops polling line amongst many devices supported btam handles
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Operating systems
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hong kong shipping register port hong kong deep water port located southern china one hub ports serving south-east east asia region gateway mainland china city hong kong began colony united kingdom free port became international trade center connecting land sea transport china countries port mature infrastructure well-developed air-sea-land transport helps hong kong maintain position international trade centre transshipment hub part 1997 transfer sovereignty hong kong britain china ship registration system made adjustments 1990 marine department set separate system hong kong shipping register ordinance hong kong ship registration amended accordingly new measures reduce operation cost ship management also improve service quality new system increased hong kong competitive advantage attracting ships port january 2009 hong kong registered ships reached 40.56 million tons 1,380 vessels
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Databases
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philip van cleave philip van cleave born 1952 kankakee illinois american gun rights advocate computer programmer president virginia citizens defense league vcdl 2018 appeared show america instructed preschool children use guns fictitious show van cleave grew illinois 16 mother bought first gun .410 bore shotgun 21 volunteered reserve deputy sheriff san antonio purchased first .357 magnum ruger service revolver van cleave joined virginia citizens defense league 1995 year founded june 2004 received gun rights defender month award citizens committee right keep bear arms van cleave proponent strong interpretation second amendment united states constitution believing open access guns guarantees individual americans right defend put 2004 take back country ever become totalitarian state although gun rights groups citizens committee right keep bear arms criticized vcdl members open carry en masse van cleave defended practice saying helps educate citizens police virginia gun laws also defended vcdl advocacy passing concealed carry laws allow college students carry guns campus permit saying virginia tech shooting one adult students armed building would much better chance somebody would stopped madman 2010 reported pressuring virginia lawmakers legalize gun carrying drinking among non-police officers well police officers long drunk carrying gun arguing 're allowed drink two classes citizens van cleave interviewed 60-minutes nightline washington post host places van cleave appeared daily show 2013 segment gun control australia show interviewed john oliver said gun control end day none works went say united states high gun crime rates many guns oliver replied point 2018 van cleave appeared fake promotional pro-gun rights video advocating arming children toddlers sacha baron cohen showtime spoof interview series america baron cohen disguised israeli ex-mossad agent invited van cleave washington dc receive friend israel award honor israel 70th anniversary fictitious pro-israel group created baron cohen segment van cleave endorses “ kinderguardians ” phony program teach arm schoolchildren young three protect classroom segment van cleave argued since children developed conscience would make effective soldiers notable pro-gun politicians duped fake award appearing segment including former us senate majority leader trent lott former us congressman joe walsh former chief justice alabama supreme court roy moore
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Programming language topics
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scope resolution operator computer programming scope enclosing context values expressions associated scope resolution operator helps identify specify context identifier refers particularly specifying namespace specific uses vary across different programming languages notions scoping many languages scope resolution operator written languages notably influenced modula-3 including python go modules objects scope resolution within modules special case usual object member access usual method operator codice_1 used scope resolution languages notably c++ ruby feature scope resolution method access interact various ways see examples php scope resolution operator also called paamayim nekudotayim second word colloquial corruption נקודתיים means “ double colon ” hebrew name paamayim nekudotayim introduced israeli-developed zend engine 0.5 used php 3 although confusing many developers speak hebrew still used php 7 sample error message similar error also occur scope resolution operator present example attempting check whether constant empty triggers error php 5.4 error messages concerning scope resolution operator still include name clarified meaning somewhat less obvious ways trigger error example attempting use following invalid php expression ruby scope resolution specified using namespaces classes modules scope also affected sigils preface variable names
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Programming language topics
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fmod fmod proprietary sound effects engine authoring tool video games applications developed firelight technologies play mix sounds diverse formats many operating systems fmod sound system supplied programmer api authoring tool similar digital audio workstation fmod consists following technologies legacy products fmod sound system advanced plugin architecture used extend support audio formats develop new output types e.g streaming fmod available multiple license schemes fmod written portable c++ thus run many different pc mobile gaming console platforms including microsoft windows x86 x86-64 macos ios linux x86 x86-64 android blackberry wii wii u 3ds nintendo switch xbox xbox 360 xbox one playstation 2 playstation 3 playstation 4 playstation portable playstation vita google native client fmod contains support amd trueaudio sound blaster hardware acceleration fmod play back following audio formats aiff asf asx dls flac fsb fmod sample bank format m3u midi mod mp2 mp3 ogg vorbis pls s3m vag ps2/psp format wav wax windows media audio redirector wma xm xma xbox 360 well raw audio data fmod integrated primary sound-effects system following video game engines fmod used many high-profile commercial games since release partial list
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Distributed computing architecture
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bytemark bytemark uk-based server hosting datacentre provider headquartered york united kingdom founded 2002 bytemark computer consulting ltd bytemark first provider virtual machines cloud hosting user-mode linux 2003 2012 bytemark launched bigv public cloud platform designed completely in-house using open source software 2013 bytemark moved £1.2 million datacentre headquarters york yo26 2017 bigv platform renamed bytemark cloud september 2018 bytemark acquired iomart group plc yo26 datacentre uses fresh-air cooling common uk shortlisted innovation medium data center datacenterdynamics awards emea 2013 bytemark servers built using efficient power supplies certified 80plus scheme requires power supplies least 80 efficient 100 rated load reduce bias found traditional recruitment processes bytemark developed anonymous recruitment process 2015 2014 bytemark named one top 50 fastest grown tech companies north northern tech awards revenue growth 44 financially bytemark turned £2.5 million 2013 2014 grew £3 million 2015 bytemark awarded fair tax mark bytemark history contributing supporting free software bytemark offers ongoing discount least 5 free software publishers bytemark support libreoffice provision build server 2009 bytemark became supporter xbmc 2012 bytemark started supporting cyanogenmod build servers 2013 bytemark contributed hosting services worth £150,000 debian project used debian since company founded bytemark also supports openstreetmap dns services servers support version control mailing lists help pages bytemark also support projects social good including sponsoring servers mysociety including fixmystreet theyworkforyou whatdotheyknow
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Distributed computing architecture
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firefox sync firefox sync originally branded mozilla weave browser synchronization feature allows users partially synchronize bookmarks browsing history preferences passwords filled forms add-ons last 25 opened tabs across multiple computers keeps user data mozilla servers according mozilla data encrypted way third party even mozilla access user information also possible user host firefox sync servers indeed entity firefox sync originally add-on mozilla firefox 3.x seamonkey 2.0 built-in feature since firefox 4.0 seamonkey 2.1 firefox sync built top firefox accounts firefox 29 therefore firefox 29 later sync firefox 28 earlier firefox home companion application iphone ipod touch based firefox sync technology allowed users either device access firefox browsing history bookmarks recent tabs also included firefox awesomebar location bar firefox home browser application launches pages either webkit web viewer safari mozilla pulled firefox home app store september 2012 stating would focus resources projects company subsequently released source code firefox home underlying synchronization software december 2014 mozilla announced designing version firefox ios due apple application review policies firefox use built-in ios webkit-based rendering framework instead gecko browser able sync firefox browsing history bookmarks recent tabs mozilla also offers synchronization server application use firefox sync users businesses prefer host synchronization data
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Distributed computing architecture
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network driver interface specification network driver interface specification ndis application programming interface api network interface cards nics jointly developed microsoft 3com corporation mostly used microsoft windows however open-source ndiswrapper project evil driver wrapper projects allow many ndis-compliant nics used linux freebsd netbsd magnussoft zeta derivative beos supports number ndis drivers ndis forms logical link control llc sublayer upper sublayer osi data link layer layer 2 therefore ndis acts interface media access control mac sublayer lower sublayer data link layer network layer layer 3 ndis library functions often referred wrapper hides underlying complexity nic hardware serves standard interface level 3 network protocol drivers hardware level mac drivers ndis versions supported various windows versions follows traffic accepted nic controlled ndis miniport driver various protocols tcp/ip implemented ndis protocol drivers single miniport may associated one protocols means traffic coming miniport may received parallel several protocol drivers example winpcap adds second protocol driver selected miniport order capture incoming packets furthermore possible simulate several virtual nics implementing virtual miniport drivers send receive traffic single physical nic one example virtual miniport driver usage add virtual nics different virtual lan implementations assume drivers received buffers one must treat incoming buffers read driver changes packet content must allocate buffers miniport type hardware driver part windows driver model usb audio scsi network card adapters usually source binary compatible windows 98 windows 2000 hardware specific control access hardware specific bus class driver another driver type ndis intermediate driver intermediate drivers sit in-between mac ip layers control traffic accepted nic practice intermediate drivers implement miniport protocol interfaces miniport driver protocol driver actually communicate corresponding miniport protocol interfaces reside intermediate driver design enables adding several chained intermediate drivers miniport protocol drivers therefore driver vendors assume interface send traffic implemented last driver chain order write applications using ndis one use samples accompany microsoft windows driver kit wdk passthru sample good starting point intermediate drivers implements necessary details required driver type passes traffic next driver chain
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Operating systems
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bada bada stylized bada korean discontinued operating system mobile devices smartphones tablet computers developed samsung electronics name derived bada meaning ocean sea korean ranges mid- high-end smartphones foster adoption bada os since 2011 samsung reportedly considered releasing source code open-source license expanding device support include smart tvs samsung announced june 2012 intentions merge bada tizen project would meanwhile use bada operating system parallel google android os microsoft windows phone smartphones devices running bada branded wave name unlike samsung devices branded name galaxy encompass whole range samsung devices running android 25 february 2013 samsung announced would stop developing bada moving development tizen instead bug reporting finally terminated april 2014 announcement bada wave s8500 would eventually turn first bada-based phone first shown public mobile world congress 2010 barcelona february 2010 alongside bada applications running bada exhibited including mobile videogames like gameloft asphalt 5 samsung wave s8500 released april year sold one million handsets first four weeks market according samsung companies twitter ea capcom gameloft blockbuster revealed support bada platform arranged development partnerships samsung since launch shared insights vision future mobile apps bada would play role showcase could heard series events held across world year 2010 called developer days addition made public announcement incoming bada developer challenge total prize 2,700,000 usd throughout launch event may 2010 samsung released beta bada software development kit sdk making available general public done partners previous december entice potential developers applications platform august 2010 samsung released version 1.0 bada sdk year later august 2011 version 2.0 bada sdk released samsung s8500 wave launched version 1.0 bada operating system samsung soon released version 1.0.2 included minor fixes european users latest version 1.2 released samsung s8530 wave ii phone alpha-version bada 2.0 introduced 15 february 2011 samsung s8530 wave ii handset current flagship bada handset samsung wave 3 s8600 running bada 2.0 release samsung wave samsung opened international application store samsung apps bada platform samsung apps 2400 applications store also available android samsung feature phones samsung remove bada brand market new os tizen apps store new store around 1000 applications tizen bada samsung defines operating system platform kernel configurable architecture allows using either proprietary real-time operating system hybrid rtos kernel linux kernel according copyrights displayed samsung wave s8500 uses code freebsd netbsd openbsd despite numerous suggestions known bada device date running linux kernel similarly evidence bada uses similar graphics stack tizen os particular efl device layer provides core functions graphics protocols telephony security service layer provides service-centric features sms mapping in-app-purchasing provide features so-called bada server top layer framework layer provides application programming interface api c++ application developers use bada provides various ui controls developers provides assorted basic ui controls listbox color picker tab web browser control based open-source webkit features adobe flash supporting flash 9 10 11 flash lite 4 actionscript 3.0 support bada 2.0 webkit flash embedded inside native bada applications bada supports opengl es 2.0 3d graphics api offers interactive mapping point interest poi features also embedded inside native applications supports pinch-to-zoom tabbed browsing cut copy paste features bada supports many mechanisms enhance interaction incorporated applications include various sensors motion sensing vibration control face detection accelerometer magnetometer tilt global positioning system gps multi-touch native applications developed c++ bada sdk eclipse based integrated development environment ide gnu-based tool chains used building debugging applications ide also contains ui builder developers easily design interface applications dragging dropping ui controls forms testing debugging ide contains emulator run apps publications criticized bada 1.x following issues bada 2.0 version shown ifa 2011 berlin released end december 2011 lot new functions improvements compared version 1.2 introducing features end 2011 samsung released three new models preloaded bada 2.0 ending list devices running short-lived bada chart show global sales bada smartphones second quarter 2010 second quarter 2013 canalys technology market analysis company estimated samsung shipped 3.5 million phones running bada q1 2011 rose 4.5 million phones q2 2011 according gartner q1 2012 bada gained grow index +43 rose 2.7 market share 1.9 q1 2011 south korea fiscal year calendar year
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Operating systems
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articulatory phonology articulatory phonology linguistic theory originally proposed 1986 catherine browman haskins laboratories louis m. goldstein yale university haskins theory identifies theoretical discrepancies phonetics phonology aims unify two treating low- high-dimensional descriptions single system unification achieved incorporating single model idea physical system identified phonetics constrains underlying abstract system identified phonology making units control abstract planning level physical level plan utterance formatted gestural score provides input physically based model speech production task dynamic model elliot saltzman gestural score graphs locations within vocal tract constriction occur indicating planned target degree constriction computational model speech production developed haskins laboratories combines articulatory phonology task dynamics haskins articulatory synthesis system developed philip rubin colleagues
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Computational linguistics
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dwight agnew dwight merle agnew january 1 1902 – october 4 1969 united states navy officer fredericktown ohio destroyer commander world present attack pearl harbor later received navy cross tactical acumen guadalcanal campaign post-war led destroyer squadron 10 later worked national security agency 1956 moved retired list made tombstone admiral agnew married thelma marie biegler daughter united states army officer medal honor recipient george w. biegler dwight agnew born fredericktown ohio january 1 1902 murray agnew emma louise agnew née follin graduating fredericktown high school briefly attended denison university entering united states naval academy graduated naval academy 1926 commissioned ensign prior world war ii agnew held variety shipboard postings serving aboard time nevada number four gun turret crew – leadership – trenchard medal excellence gunnery japanese attack pearl harbor december 7 1941 agnew family – dwight brother henry sisters brothers-in-law latter also navy officers – stationed hawaii time agnew serving commanding officer uss trever destroyer minesweeper like many american ship captains agnew aboard vessel attack began 0755 december 7 command junior officers uss trever sounded general alarm 0757 began returning fire japanese forces seven minutes later successfully downing imperial japanese navy air service aircraft strafing pearl city yacht club well second aircraft maneuvering attack ship frantic orders sortie fleet resulted agnew left behind aboard trever instead putting sea commander helm following attack wasmuth rendezvoused trever agnew rejoined ship trever depth charges already armed set agnew ordered magnetic sweep harbor taking defensive station harbor mouth protect feared second wave attack materialize following week december 14 agnew led trever rescue crew passengers torpedoed norwegian freighter ms høegh merchant høegh merchant sunk japanese submarine attempting navigate safe port following outbreak hostilities august 1942 agnew promoted captain continuing commanding officer agnew received navy cross tactical brilliance repelling attack imperial japanese navy upon trever task unit leading guadalcanal campaign according citation 1943 transferred san francisco california oversee outfitting new subsequently commanding ship engagements pacific received bronze star agnew given command attack transport 1945 commanded battle iwo jima following world war ii agnew held variety staff assignments navy – including naval representative joint american military mission aid turkey – january 1952 february 1953 commanding officer destroyer squadron 10 united states atlantic fleet final three years military career 1956 retirement assigned national security agency upon retirement advanced rank rear admiral died october 4 1969 october 1929 agnew married thelma marie biegler daughter army officer george w. biegler following outbreak world thelma agnew son dwight agnew jr evacuated san diego stay dwight agnew mother living city agnew brother henry also alumnus u.s naval academy instructor academy also held several shipboard assignments world given command post-war period sisters dorothy elizabeth married naval officers
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Computer security
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scheme programming language scheme programming language supports multiple paradigms including functional imperative programming one three main dialects lisp alongside common lisp clojure unlike common lisp scheme follows minimalist design philosophy specifying small standard core powerful tools language extension scheme created 1970s mit ai lab released developers guy l. steele gerald jay sussman via series memos known lambda papers first dialect lisp choose lexical scope first require implementations perform tail-call optimization giving stronger support functional programming associated techniques recursive algorithms also one first programming languages support first-class continuations significant influence effort led development common lisp scheme language standardized official ieee standard de facto standard called revised report algorithmic language scheme r n rs widely implemented standard r5rs 1998 new standard r6rs ratified 2007 scheme diverse user base due compactness elegance minimalist philosophy also caused wide divergence practical implementations much scheme steering committee calls world unportable programming language family dialects rather single language scheme started 1970s attempt understand carl hewitt actor model purpose steele sussman wrote tiny lisp interpreter using maclisp added mechanisms creating actors sending messages scheme originally called schemer tradition lisp-derived languages planner conniver current name resulted authors use operating system limited filenames two components six characters currently schemer commonly used refer scheme programmer new language standardization process began 2003 scheme workshop goal producing r6rs standard 2006 process broke earlier r n rs approach unanimity r6rs features standard module system allowing split core language libraries number drafts r6rs specification released final version r5.97rs successful vote resulted ratification new standard announced august 28 2007 currently newest releases various scheme implementations support r6rs standard portable reference implementation proposed implicitly phased libraries r6rs called psyntax loads bootstraps properly various older scheme implementations feature r6rs record-type descriptor rtd rtd created used record type representation show memory layout also calculated object field bit mask mutable scheme object field bit masks helped garbage collector know fields without traversing whole fields list saved rtd rtd allows users expand basic rtd create new record system r6rs introduces numerous significant changes language source code specified unicode large subset unicode characters may appear scheme symbols identifiers minor changes lexical rules character data also specified unicode many standard procedures moved new standard libraries form large expansion standard containing procedures syntactic forms formerly part standard new module system introduced systems exception handling standardized syntax-rules replaced expressive syntactic abstraction facility syntax-case allows use scheme macro expansion time compliant implementations required support scheme full numeric tower semantics numbers expanded mainly direction support ieee 754 standard floating point numerical representation r6rs standard caused controversy seen departed minimalist philosophy august 2009 scheme steering committee oversees standardization process announced intention recommend splitting scheme two languages large modern programming language programmers small version subset large version retaining minimalism praised educators casual implementors two working groups created work two new versions scheme scheme reports process site links working groups charters public discussions issue tracking system ninth draft r7rs small language made available april 15 2013 vote ratifying draft closed may 20 2013 final report available since august 6 2013 describing 'small language effort therefore considered isolation successor r6rs scheme primarily functional programming language shares many characteristics members lisp programming language family scheme simple syntax based s-expressions parenthesized lists prefix operator followed arguments scheme programs thus consist sequences nested lists lists also main data structure scheme leading close equivalence source code data formats homoiconicity scheme programs easily create evaluate pieces scheme code dynamically reliance lists data structures shared lisp dialects scheme inherits rich set list-processing primitives codice_1 codice_2 codice_3 lisp progenitors scheme uses strictly dynamically typed variables supports first class procedures thus procedures assigned values variables passed arguments procedures section concentrates mainly innovative features language including features distinguish scheme lisps unless stated otherwise descriptions features relate r5rs standard examples provided section notation === result used indicate result evaluating expression immediately preceding line convention used r5rs subsection describes features scheme distinguished programming languages earliest days aspects scheme strongly influence product scheme language aspects versions scheme programming language 1973 onward share scheme simple language much easier implement many languages comparable expressive power ease attributable use lambda calculus derive much syntax language primitive forms instance 23 s-expression-based syntactic constructs defined r5rs scheme standard 14 classed derived library forms written macros involving fundamental forms principally lambda r5rs says r5rs sec 3.1 fundamental variable binding constructs lambda expression variable binding constructs explained terms lambda expressions example macro implement codice_4 expression using codice_5 perform variable bindings define-syntax let thus using codice_4 defined scheme implementation would rewrite codice_7 codice_8 reduces implementation task coding procedure instantiations 1998 sussman steele remarked minimalism scheme conscious design goal rather unintended outcome design process actually trying build something complicated discovered serendipitously accidentally designed something met goals much simpler intended ... realized lambda calculus—a small simple formalism—could serve core powerful expressive programming language like modern programming languages unlike earlier lisps maclisp scheme lexically scoped possible variable bindings program unit analyzed reading text program unit without consideration contexts may called contrasts dynamic scoping characteristic early lisp dialects processing costs associated primitive textual substitution methods used implement lexical scoping algorithms compilers interpreters day lisps perfectly possible reference free variable inside procedure refer quite distinct bindings external procedure depending context call impetus incorporate lexical scoping unusual scoping model early 1970s new version lisp came sussman studies algol suggested algol-like lexical scoping mechanisms would help realize initial goal implementing hewitt actor model lisp key insights introduce lexical scoping lisp dialect popularized sussman steele 1975 lambda paper scheme interpreter extended lambda calculus adopted concept lexical closure page 21 described ai memo 1970 joel moses attributed idea peter j. landin alonzo church mathematical notation lambda calculus inspired lisp use lambda keyword introducing procedure well influencing development functional programming techniques involving use higher-order functions lisp early lisps suitable expressions lambda calculus treatment free variables formal lambda system axioms complete calculation rule helpful analysis using mathematical logic tools system calculation seen directional deduction syntax lambda calculus follows recursive expressions x z ... parentheses spaces period symbol λ function lambda calculation includes first serve starting point powerful mathematical logic second reduce requirement programmers consider implementation details use imitate machine evaluation finally lambda calculation created substantial meta-theory introduction lexical scope resolved problem making equivalence forms lambda notation practical expression working programming language sussman steele showed new language could used elegantly derive imperative declarative semantics programming languages including algol fortran dynamic scope lisps using lambda expressions simple procedure instantiations control structures environment modifiers introduced continuation-passing style along first description scheme first lambda papers subsequent papers proceeded demonstrate raw power practical use lambda calculus scheme inherits block structure earlier block structured languages particularly algol scheme blocks implemented three binding constructs codice_4 codice_10 codice_11 instance following construct creates block symbol called codice_12 bound number 10 let var 10 blocks nested create arbitrarily complex block structures according need programmer use block structuring create local bindings alleviates risk namespace collision otherwise occur one variant codice_4 codice_10 permits bindings refer variables defined earlier construct thus variant codice_11 designed enable mutually recursive procedures bound one another === 1 0 1 0 2 1 2 2 3 2 3 3 4 4 5 4 5 5 procedures bound single codice_11 may refer one another name well values variables defined earlier codice_11 may refer values defined later codice_11 variant codice_4 named let form identifier codice_4 keyword binds let variables argument procedure whose name given identifier whose body body let form body may repeated desired calling procedure named let widely used implement iteration example simple counter === 1 2 3 4 5 6 7 8 9 10 like procedure scheme procedure created named let first class object scheme iteration construct codice_21 idiomatic scheme use tail recursion express iteration standard-conforming scheme implementations required optimize tail calls support unbounded number active tail calls r5rs sec 3.5 —a property scheme report describes proper tail recursion —making safe scheme programmers write iterative algorithms using recursive structures sometimes intuitive tail recursive procedures named codice_4 form provide support iteration using tail recursion === 0 1 4 9 16 25 36 49 64 81 continuations scheme first-class objects scheme provides procedure codice_23 also known codice_24 capture current continuation packing escape procedure bound formal argument procedure provided programmer r5rs sec 6.4 first-class continuations enable programmer create non-local control constructs iterators coroutines backtracking continuations used emulate behavior return statements imperative programming languages following function codice_25 given function codice_26 list codice_27 returns first element codice_28 codice_27 codice_30 returns true === 7 === f following example traditional programmer puzzle shows scheme handle continuations first-class objects binding variables passing arguments procedures let* yin executed code displays counting sequence codice_31 contrast common lisp data procedures scheme share common namespace whereas common lisp functions data separate namespaces making possible function variable name requiring special notation referring function value sometimes known lisp-1 vs. lisp-2 distinction referring unified namespace scheme separate namespaces common lisp scheme primitives used manipulate bind data used bind procedures equivalent common lisp codice_32 codice_33 primitives define f 10 f === 10 set f f f 6 f === 26 set f lambda n n 12 === 18 set f f 1 f === 13 apply 1 2 3 4 5 6 === 21 === 101 102 103 subsection documents design decisions taken years given scheme particular character direct outcomes original design scheme specifies comparatively full set numerical datatypes including complex rational types known scheme numerical tower r5rs sec 6.2 standard treats abstractions commit implementor particular internal representations numbers may quality exactness exact number produced sequence exact operations involving exact numbers—inexactness thus contagious standard specifies two implementations must produce equivalent results operations resulting exact numbers r5rs standard specifies procedures codice_34 codice_35 used change exactness number codice_35 produces exact number numerically closest argument codice_34 produces inexact number numerically closest argument r6rs standard omits procedures main report specifies r5rs compatibility procedures standard library rnrs r5rs 6 r5rs standard scheme implementations required implement whole numerical tower must implement coherent subset consistent purposes implementation spirit scheme language r5rs sec 6.2.3 new r6rs standard require implementation whole tower exact integer objects exact rational number objects practically unlimited size precision implement certain procedures ... always return exact results given exact arguments r6rs sec 3.4 sec 11.7.1 example 1 exact arithmetic implementation supports exact rational complex numbers define x 1/3 1/4 -1/5 -1/3i 405/50+2/3i x === 509/60+1/3i exact x === example 2 arithmetic implementation supports neither exact rational numbers complex numbers accept real numbers rational notation define xr 1/3 1/4 -1/5 405/50 define xi -1/3 2/3 xr === 8.48333333333333 xi === 0.333333333333333 exact xr === f === f implementations conform r5rs standard second conform r6rs implement full numerical tower scheme supports delayed evaluation codice_38 form procedure codice_39 === 22 === 70 === 22 lexical context original definition promise preserved value also preserved first use codice_39 promise ever evaluated primitives produce handle values known promises used implement advanced lazy evaluation constructs streams r6rs standard longer primitives instead provided part r5rs compatibility library rnrs r5rs 6 r5rs suggested implementation codice_38 codice_39 given implementing promise procedure arguments thunk using memoization ensure ever evaluated irrespective number times codice_39 called r5rs sec 6.4 srfi 41 enables expression finite infinite sequences extraordinary economy example definition fibonacci sequence using functions defined srfi 41 define fibs stream-ref fibs 99 === 218922995834555169026 lisps specify order evaluation procedure arguments scheme order evaluation—including order expression operator position evaluated—may chosen implementation call-by-call basis constraint effect concurrent evaluation operator operand expressions constrained consistent sequential order evaluation r5rs sec 4.1.3 === 3 ev procedure describes argument passed returns value argument contrast lisps appearance expression operator position first item scheme expression quite legal long result expression operator position procedure calling procedure add 1 2 expressions ev ev 1 ev 2 may evaluated order long effect evaluated parallel thus following three lines may displayed order standard scheme example code executed although text one line may interleaved another would violate sequential evaluation constraint r5rs standard also later reports syntax scheme easily extended via macro system r5rs standard introduced powerful hygienic macro system allows programmer add new syntactic constructs language using simple pattern matching sublanguage r5rs sec 4.3 prior hygienic macro system relegated appendix r4rs standard high level system alongside low level macro system treated extensions scheme rather essential part language implementations hygienic macro system also called codice_44 required respect lexical scoping rest language assured special naming scoping rules macro expansion avoids common programming errors occur macro systems programming languages r6rs specifies sophisticated transformation system codice_45 available language extension r5rs scheme time define-syntax invocations macros procedures bear close resemblance—both s-expressions—but treated differently compiler encounters s-expression program first checks see symbol defined syntactic keyword within current lexical scope attempts expand macro treating items tail s-expression arguments without compiling code evaluate process repeated recursively macro invocations remain syntactic keyword compiler compiles code evaluate arguments tail s-expression evaluate variable represented symbol head s-expression call procedure evaluated tail expressions passed actual arguments scheme implementations also provide additional macro systems among popular ones syntactic closures explicit renaming macros codice_46 non-hygienic macro system similar codice_47 system provided common lisp inability specify whether macro hygienic one shortcomings macro system alternative models expansion scope sets provide potential solution prior r5rs scheme standard equivalent codice_48 procedure ubiquitous lisps although first lambda paper described codice_49 similar lisp function eval first revised report 1978 replaced codice_50 took two arguments second third fourth revised reports omitted equivalent codice_48 reason confusion scheme lexical scoping result evaluating expression depends evaluated instance clear whether result evaluating following expression 5 6 evaluated outer environment codice_52 defined result sum operands evaluated inner environment symbol bound value procedure result product two operands r5rs resolves confusion specifying three procedures return environments providing procedure codice_48 takes s-expression environment evaluates expression environment provided r5rs sec 6.5 r6rs extends providing procedure called codice_54 programmer specify exactly objects import evaluation environment dialects lisp including common lisp convention value codice_55 evaluates value false boolean expression scheme since ieee standard 1991 values except f including codice_55 equivalent scheme written evaluate value true boolean expression r5rs sec 6.3.1 constant representing boolean value true codice_57 lisps scheme codice_58 scheme primitive datatypes disjoint one following predicates true scheme object codice_59 codice_60 codice_61 codice_62 codice_63 codice_64 codice_65 codice_66 codice_67 r5rs sec 3.2 within numerical datatype contrast numerical values overlap example integer value satisfies codice_68 codice_69 codice_70 codice_71 codice_62 predicates time r5rs sec 6.2 scheme three different types equivalence arbitrary objects denoted three different equivalence predicates relational operators testing equality codice_73 codice_74 codice_75 type dependent equivalence operations also exist scheme codice_83 codice_84 compare two strings latter performs case-independent comparison codice_85 codice_86 compare characters codice_87 compares numbers r5rs standard standard comment scheme semicolon makes rest line invisible scheme numerous implementations supported alternative conventions permitting comments extend single line r6rs standard permits two entire s-expression may turned comment commented preceding codice_88 introduced srfi 62 multiline comment block comment may produced surrounding text codice_89 codice_90 scheme input output based port datatype r5rs sec 6.6 r5rs defines two default ports accessible procedures codice_91 codice_92 correspond unix notions standard input standard output implementations also provide codice_93 redirection input standard output supported standard standard procedures codice_94 codice_95 implementations provide string ports similar redirection capabilities enabling many normal input-output operations performed string buffers instead files using procedures described srfi 6 r6rs standard specifies much sophisticated capable port procedures many new types port following examples written strict r5rs scheme example 1 output defaulting current-output-port example 2 1 using optional port argument output procedures example 3 1 output redirected newly created file let hello0 lambda display hello world newline example 4 2 explicit file open port close send output file example 5 2 using call-with-output-file send output file similar procedures provided input r5rs scheme provides predicates codice_96 codice_97 character input output codice_98 codice_99 codice_100 codice_101 provided writing reading scheme expressions scheme provides codice_102 codice_103 read operation result returned end-of-file object input port reached end file tested using predicate codice_104 addition standard srfi 28 defines basic formatting procedure resembling common lisp codice_105 function named scheme procedures bound variables r5rs language standard formally mandated programs may change variable bindings built-in procedures effectively redefining r5rs language changes example one may extend codice_106 accept strings well numbers redefining set === 6 === 123 r6rs every binding including standard ones belongs library exported bindings immutable r6rs sec 7.1 redefinition standard procedures mutation forbidden instead possible import different procedure name standard one effect similar redefinition standard scheme procedures convert one datatype another contain character string name predicates end procedures change value already-allocated data end conventions often followed scheme programmers formal contexts scheme standards word procedure used preference function refer lambda expression primitive procedure normal usage words procedure function used interchangeably procedure application sometimes referred formally combination lisps term thunk used scheme refer procedure arguments term proper tail recursion refers property scheme implementations perform tail-call optimization support indefinite number active tail calls form titles standards documents since r3rs revised report algorithmic language scheme reference title algol 60 standard document revised report algorithmic language algol 60 summary page r3rs closely modeled summary page algol 60 report language formally defined standards r5rs 1998 r6rs 2007 describe standard forms keywords accompanying syntax provide control structure language standard procedures perform common tasks table describes standard forms scheme forms appear one row easily classified single function language forms marked l table classed derived library forms standard often implemented macros using fundamental forms practice making task implementation much easier languages note codice_107 defined library syntax r5rs expander needs know achieve splicing functionality r6rs longer library syntax following two tables describe standard procedures r5rs scheme r6rs far extensive summary type would practical procedures appear one row easily classified single function language string character procedures contain -ci names perform case-independent comparisons arguments upper case lower case versions character taken equal implementations take two arguments defined left optional r5rs scheme minimalism many common procedures syntactic forms defined standard order keep core language small facilitate standardization extensions scheme community scheme request implementation srfi process extension libraries defined careful discussion extension proposals promotes code portability many srfis supported scheme implementations srfis fairly wide support different implementations include elegant minimalist design made scheme popular target language designers hobbyists educators small size typical interpreter also popular choice embedded systems scripting resulted scores implementations differ much porting programs one implementation another quite difficult small size standard language means writing useful program great complexity standard portable scheme almost impossible r6rs standard specifies much broader language attempt broaden appeal programmers almost implementations provide traditional lisp-style read–eval–print loop development debugging many also compile scheme programs executable binary support embedding scheme code programs written languages also common relative simplicity scheme implementations makes popular choice adding scripting capabilities larger systems developed languages c. gambit chicken bigloo scheme interpreters compile scheme c makes embedding particularly easy addition bigloo compiler configured generate jvm bytecode also features experimental bytecode generator .net implementations support additional features example kawa jscheme provide integration java classes scheme c compilers often make easy use external libraries written c allowing embedding actual c code scheme source another example pvts offers set visual tools supporting learning scheme scheme widely used number schools particular number introductory computer science courses use scheme conjunction textbook structure interpretation computer programs sicp past 12 years plt run programbydesign formerly teachscheme project exposed close 600 high school teachers thousands high school students rudimentary scheme programming mit old introductory programming class 6.001 taught scheme although 6.001 replaced modern courses sicp continues taught mit textbook design programs matthias felleisen currently northeastern university used institutes higher education introductory computer science courses northeastern university worcester polytechnic institute use scheme exclusively introductory courses fundamentals computer science cs2500 introduction program design cs1101 respectively rose-hulman uses scheme advanced programming language concepts course indiana university introductory class c211 taught entirely scheme introductory class uc berkeley cs 61a 2015 taught entirely scheme save minor diversions logo demonstrate dynamic scope course materials including lecture webcasts available online free charge self-paced version course cs 61as continues use scheme introductory computer science courses yale grinnell college also taught scheme programming design paradigms mandatory course computer science graduate students northeastern university also extensively uses scheme introductory computer science course university minnesota twin cities csci 1901 also uses scheme primary language followed course introduces students java programming language software industry tata consultancy services asia largest software consultancy firm uses scheme month-long training program fresh college graduates scheme is/was also used following
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Programming language topics
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mklivecd mklivecd script linux distributions allows one compile snapshot current hard drive partition data resides settings applications documents bookmarks etc compress iso 9660 cd-image allows easy backup user data also makes easy create customized linux-distribution linux-distributions like pclinuxos include graphical frontend easier script usage
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Operating systems
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intervalzero intervalzero inc. develops hard real-time software symmetric multiprocessing smp enabled rtx rtx64 software transform microsoft windows general-purpose operating system gpos real-time operating system rtos intervalzero engineering group regularly release new software cf history recent product rtx64 focuses 64-bit symmetric multiprocessing smp replace dedicated hardware based systems digital signal processors dsps field-programmable gate arrays fpgas multicore pcs instance audio mixing surface manufacturer largely deployed dsp based systems switched personal computer pc based systems dedicating multi-core processors real time audio processing founded july 2008 group former ardence executives intervalzero headed ceo jeffrey d. hibbard firm offices waltham nice france munich germany taiwan roc global presence important solutions deployed worldwide primarily industrial automation military aerospace medical devices digital media test simulation software corporate name intervalzero comes firm mission deliver deterministic hard real-time functionality interval zero technical definition optimal experience system command execution intervalzero lineage traces back 1980 group massachusetts institute technology mit engineers started venturcom began develop expertise embedded technology time venix developed marketed first innovation focus windows nt 4.0 possible real-time solution industry 1995 releasing rtx since lot controllers pc windows based second innovation came second product component integrator makes windows nt 4.0 embedded os licensed microsoft years later became origin windows nt embedded 2004 venturcom renamed ardence 20 december 2006 citrix systems announced agreement acquire ardence enterprise embedded software businesses integrated software streaming products citrix portfolio 2007 early 2008 2008 group former ardence executives founded intervalzero acquired ardence embedded software business citrix systems inc. citrix retained minority ownership firm intervalzero develops following products
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Operating systems
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apcera apcera american cloud infrastructure company provides container management platform deploy orchestrate govern containers applications across on-premises cloud-based infrastructure apcera founded 2012 san francisco derek collison previously technology leader google tibco vmware designed first open platform-as-a-service paas cloud foundry apcera ’ primary offering apcera cloud platform provides governance security policy driven model allowing safe deployment management cloud-native applications microservices legacy applications well resources network services access user permissions according forbes tech apcera cloud platform enables clients manage migration legacy infrastructure newer approaches ... allows achieve significantly faster time-to-market … critical deployments without sacrificing crucial security requirements ” september 2014 ericsson acquired majority stake apcera cloud policy compliance apcera cloud platform available two forms community edition enterprise edition community edition free used deployment single infrastructure enterprise edition functionality deploy workloads multiple infrastructures apcera cloud platform allows user create set rules control available resources container level addition allows user connect back-end services outside platform maintaining governance allows users build workload move around container without re-writing code — needs connections made containers apcera also develops provides support several open source software projects including nats cloud-native enterprise messaging system kurma container runtime extensibility flexibility libretto golang virtual machine provisioning library public private clouds apcera ’ customers include nextsource ericsson qualcomm cygate rodan fields
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Distributed computing architecture
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fat filesystem linux linux several filesystem drivers file allocation table fat filesystem format commonly known names used codice_1 command invoke particular drivers kernel msdos vfat umsdos linux filesystem drivers support three fat types namely fat12 fat16 fat32 differ provision support long filenames beyond 8.3 filename structure original fat filesystem format provision unix file semantics exist standard fat filesystem format file permissions filesystem drivers mutually exclusive one used mount given disk volume given time thus choice among determined long filenames unix semantics support use one wants make disk volume msdos filesystem driver provides extra unix file semantics long filename support fat disk filesystem mounted using driver 8.3 filenames visible long filenames accessible long filename data structures kind disk volume maintained vfat filesystem driver provides long filename support using disk data structures microsoft windows uses vfat long filename support fat format volumes support extra unix file semantics umsdos filesystem driver provides long filename support extra unix file semantics however using on-disk data structures recognized filesystem drivers operating systems linux key advantage umsdos three provides full unix file semantics therefore used situations desirable install linux run fat disk volume require semantics available however linux installed running disk volume slower linux installed running disk volume formatted example ext2 filesystem format unless utility program regularly run every time one switches running windows running linux certain changes made files directories disk windows cause error messages inaccessible files linux vfat whilst lacking full unix file semantics lacking ability linux installed running fat disk volume aforementioned disadvantages umsdos comes simply sharing data fat disk volume linux operating systems windows data structures used windows vfat long filenames require running synchronization utility order prevent windows linux data structures becoming disjointed reason appropriate linux fat filesystem drivers use majority situations mentioned previously linux filesystem drivers support three file allocation table sizes 12-bit 16-bit 32-bit common features support various linux mounting options specified codice_2 option codice_1 command umsdos fat filesystem driver stores extra information relating unix file semantics another fat filesystem driver appears normal file directory subdirectory named codice_14 absence file given directory thus default umsdos filesystem driver provides semantics msdos filesystem driver directory 8.3 filenames extra unix file semantics enable umsdos driver extra abilities necessary create file directory synchronize internal data normal fat data existing entries already directory done tool called codice_15 utility program run across every directory disc volume every time one switches running windows running linux order umsdos filesystem driver incorporate changes made files directories windows private data structures codice_14 file default codice_15 tool creates codice_14 files directories already exist resulting file every directory disc volume switching windows linux behaviour often considered desirable therefore normal mode operation invoking codice_15 switching windows linux usually done running tool linux boot time startup script employ codice_20 option command prevents creation new codice_14 files directories already possess mentioned umsdos permits installing linux bootstrapping running fat format disc volume advantage permits use linux computer dos already installed without requiring hard disc repartitioned linux bootstrapped directly volume boot record scenario instead dos first bootstrapped loadlin linld used bootstrap linux dos convention installation linux root directory subdirectory actual root directory dos boot volume e.g codice_22 various linux top-level directories thus dos directories codice_23 codice_24 codice_25 codice_26 codice_27 codice_28 forth umsdos filesystem driver automatically prepends codice_29 pathnames location linux root directory supplied umsdos filesystem driver first place via option codice_30 command example aforegiven root directory codice_30 would invoked command line loadlin c \linux\boot\vmlinuz rw root=c \linux installation linux directory first place simply involves unpacking files archive directory subdirectories installation also generally requires use swap file rather swap partition linux however related desire repartition hard disc unrelated umsdos filesystem driver per se major linux distributions including redhat suse debian employ umsdos permit installation linux fat disc volume distributions however include distributions phat linux installs codice_32 dos unpacking zip file booted running command.com script named codice_33 zipslack umsdos project started 1992 jacques gelinas made available net january 1994 patch included standard distribution starting kernel 1.1.36 umsdos removed linux 2.6.11 kernel lack maintenance uvfat extension umsdos use windows data structures long filenames instead discontinued release work 2.4.x kernels earlier linux distributions used umsdos mulinux monkey linux winlinux 2000 although filesystem drivers kernel make possible access files directories fat formatted volumes normal manner also possible without kernel driver support using utility programs form mtools utility suite like vfat fat filesystem driver mtools provides long filename support using disc data structures microsoft windows uses alternately one fuse filesystem drivers may used—fatfuse fusefat mountlo modern equivalent umsdos posix overlay filesystem posixovl works fuse
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Computer file systems
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cyberduck cyberduck open-source client ftp sftp webdav cloud storage openstack swift amazon s3 backblaze b2 microsoft azure available macos windows version 4.0 licensed gpl cyberduck written java c using cocoa user interface framework macos windows forms windows supports ftp/tls ftp secured ssl/tls using auth tls well directory synchronization user interacts user interface gui including file transfer drag drop notifications via growl also able open files external text editors cyberduck includes bookmark manager supports apple keychain bonjour networking supports multiple languages including english catalan czech chinese traditional simplified danish dutch finnish french german hebrew hungarian indonesian italian japanese korean norwegian polish portuguese russian slovak spanish swedish thai turkish ukrainian welsh cyberduck creator also provides version command-line interface cli called duck available windows macos linux website duck.sh
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Internet protocols
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jovial jovial high-level computer programming language similar algol specialized development embedded systems specialized computer systems designed perform one dedicated functions usually embedded part complete device including mechanical parts jovial developed new high-order programming language beginning 1959 team system development corporation sdc headed jules schwartz compose software electronics military aircraft name jovial acronym jules version international algorithmic language international algorithmic language ial name originally proposed algol 58 according schwartz language originally called ovial met opposition various reasons jovial suggested meaning attached j somewhat jokingly suggested language named schwartz since chairing meeting unofficial name stuck 1960s jovial part us military l-project series particular 465l saccs project due lack real-time processing languages available 95 percent saccs project managed itt software primarily written sdc written jovial software project took two years fewer 1400 programmer years less half equivalent time sage l-project late 1970s early 1980s u.s. air force adopted standardized cpu mil-std-1750a subsequent jovial programs built processor several commercial vendors provided compilers related tools build jovial processors mil-std-1750a including advanced computer techniques act tld systems proprietary software systems pss others jovial standardized 1973 mil-std-1589 revised 1984 mil-std-1589c still much used update maintain software older military vehicles aircraft three dialects common use j3 j3b-2 j73 jovial longer maintained distributed usaf jovial program office jpo software previously distributed jpo still available commercial resources software engineering associates inc. sea combinations host/target processors including microsoft windows linux mac os x powerpc sparc vax 1750a powerpc ti-9989 zilog z800x motorola 680x0 ibm system 360/system 370/system z addition ddc-i acquired parts advanced computer techniques also still lists jovial compilers related tools software implemented jovial mission critical maintenance getting difficult december 2014 reported software derived jovial code produced 1960s involved major failure united kingdom air traffic control infrastructure agency uses train staff jovial could maintain software scheduled replacement 2016 conversion jovial code new platforms therefore becoming common jovial rehosting retargeting currently done software engineering associates conversions jovial languages currently done semantic designs whose dms software reengineering toolkit used convert jovial mission software b-2 bomber c. languages influenced jovial include coral sympl space programming language spl extent cms-2 interactive subset jovial called tint similar joss developed 1960s jovial includes features found standard algol records arrays records inline assembly language notable systems using jovial include airborne radar systems embedded jovial software include apg-70 apg-71 apg-73 following example taken computer programming manual jovial j73 language proc retrieve code value example defines procedure named codice_1 takes unsigned integer input argument codice_2 floating-point output argument codice_3 searches 1000-element array codice_4 entry matches codice_2 sets floating-point variable codice_3 element array codice_7 matching array index matching element found codice_3 set codice_9
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Programming language topics
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salesforce.com salesforce.com inc. usually abbreviated sf sfdc american cloud-based software company headquartered san francisco california though bulk revenue comes customer-relationship management crm service salesforce training also sells complementary suite enterprise applications focused customer service marketing automation analytics application development salesforce ranked first fortune 100 best companies work 2018 company founded 1999 former oracle executive marc benioff parker harris dave moellenhoff frank dominguez company specializing software service saas harris moellenhoff dominguez three software developers previously consulting firm left coast software introduced benioff friend former oracle colleague bobby yazdani harris team wrote initial sales automation software launched first customers sept-nov 1999 june 2004 company initial public offering new york stock exchange stock symbol crm raised us 110 million early investors include larry ellison magdalena yesil halsey minor stewart henderson mark iscaro igor sill geneva venture partners july 2012 salesforce applied trademark term social enterprise united states european union jamaica term widespread use describe businesses primarily social purpose successfully challenged campaign called notinourname launched social enterprise uk resulting salesforce.com withdrawing trademark application agreeing use term future marketing october 2014 salesforce announced development customer success platform tie together salesforce services including sales service marketing analytics community mobile apps october 2017 salesforce launched facebook analytics tool business-to-business marketers september 2018 salesforce partnered apple intended improving apps businesses salesforce.com customer-relationship management crm service comprises several broad categories commerce cloud sales cloud service cloud data cloud including jigsaw marketing cloud community cloud including chatter analytics cloud app cloud iot 100,000 customers salesforce primary enterprise offering within salesforce platform provides companies interface case management task management system automatically routing escalating important events salesforce customer portal provides customers ability track cases includes social networking plug-in enables user join conversation company social networking web sites provides analytical tools services including email alert google search access customers entitlement contracts lightning platform also known force.com platform service paas allows developers create add-on applications integrate main salesforce.com application third-party applications hosted salesforce.com infrastructure force.com applications built using declarative tools backed lightning apex proprietary java-like programming language force.com lightning visualforce framework includes xml syntax typically used generate html force.com platform typically receives three complete releases year platform provided service developers every single development instance also receives updates spring 2015 release new framework building user interfaces – lightning components – introduced beta lightning components built using open-source aura framework support apex server-side language instead aura javascript dependency described alternative necessarily replacement visualforce pages according september 2009 gartner group report force.com 1,000 customer accounts 2013 force.com platform 1.4 million registered developers community cloud provides salesforce customers ability create online web properties external collaboration customer service channel sales custom portals instance salesforce tightly integrated sales cloud service cloud app cloud community cloud quickly customized provide wide variety web properties work.com previously rypple social performance management platform helps managers employees improve work performance continuous coaching real-time feedback recognition marketed solution sales performance customer service marketing service employed human resource departments work.com known rypple founded daniel debow david stein wanted create simple way asking feedback anonymously work company formed may 2008 client list included mozilla facebook linkedin gilt groupe rypple 'reverses onus demand feedback getting employees build manage coaching networks september 2011 rypple announced hired bohdan zabawskyj chief technology officer 2011 rypple developed formalized management methodology called okr objectives key results spotify rypple also partnered facebook create loops short feedback loops gathers feedback co-workers thank progress goals coaching supervisors one channel rich robust continuous performance review december 2011 salesforce.com announced would acquire rypple transaction completed 2012 rypple rebranded work.com september 2012 launched 2005 salesforce appexchange online application marketplace third-party applications run force.com platform applications available free well via yearly monthly subscription models applications available range integrations sharepoint mobile approval management june 2016 features 2,948 applications driven 3+ million installs appexchange also place customers search cloud consulting partners help implement technology organization cloud consulting partners salesforce include large companies like ibm bluewolf accenture well smaller ones like cloudreach announced 2017 launched 2019 salesforce mytrailhead online training platform customized specific needs customers platform extends functionality salesforce built provide users training content specific usage salesforce enables users create publish training content programs announced may 29 2019 salesforce launched blockchain platform facilitate building blockchain network apps integrated crm data.com previously known jigsaw cloud-based automated system acquiring managing crm records within user salesforce.com account data.com also online business directory companies business professionals built maintained accessed worldwide community million subscribers. information consisted commonly found business card data.com competitors included services dun bradstreet/avention zoominfo data.com made three products data.com connect data.com clean data.com prospector april 2018 salesforce announced would retire data.com connect may 4 2019 salesforce also announced wind data.com clean data.com prospector services close july 31 2020 desk.com saas help desk customer support product accessible cloud desk.com owned salesforce.com previously known assistly desk.com headquartered san francisco california acquired salesforce.com 50 million 2011 assistly re-branded desk.com 2012 customer support software desk.com saas customer service application product differentiates salesforce service platform desk.com specifically targets small businesses features functions desk.com integrates variety products third-party applications including salesforce crm salesforce iq atlassian jira mailchimp apps desk.com also supports 50 languages salesforce announced retirement desk.com replacing service cloud lightning march 13 2018 new desk.com licenses sold retirement date announced march 13 2020 do.com cloud-based task management system small groups businesses introduced 2011 discontinued 2014 salesforce offer reason shutting service however provided export tool save data entered within do.com interface do.com domain sold startup 2014 salesforce users configure crm application system tabs contacts reports accounts tab contains associated information configuration done tab adding user-defined custom fields configuration also done platform level adding configured applications salesforce instance adding sets customized novel tabs specific vertical- function-level finance human resources etc features addition web interface salesforce offers soap/rest web service application programming interface api enables integration systems salesforce works model–view–controller architecture apex proprietary programming language provided force.com platform developers similar java c strongly typed object-oriented case-insensitive programming language following dot-notation curly-brackets syntax apex used execute programmed functions processes force.com platform including custom buttons links event handlers record insertion update deletion via scheduling via custom controllers visualforce pages due multitenant nature platform language strictly imposed governor limitations guard code monopolizing shared resources salesforce provides series asynchronous processing methods apex allow developers produce longer-running complex apex code 2014 salesforce made public front end platform called lightning component-based framework salesforce mobile app built salesforce built framework 2015 releasing lightning design system html style framework default css styling built framework allows customers build components either use internal instances sell appexchange salesforce lightning app builder tool rapid application development responsive web interfaces interface allows different screens put together based lightning components used layouts records specific applications lightning experience new redesigned interface salesforce processes enhancement released 2016 since apps available appexchange need lightning built classic migrate lightning classic updated salesforce platform offers option developers employ migration techniques enable new user interface switch lightning salesforce headquartered san francisco regional headquarters morges switzerland covering europe middle east africa singapore india covering asia pacific minus japan tokyo covering japan major offices toronto chicago new york city london sydney dublin hyderabad san mateo california indianapolis hillsboro oregon salesforce.com services translated 16 different languages july 31 2011 104,000 customers 2.1 million subscribers salesforce move midwest regional headquarters indianapolis 2017 standard poor included salesforce time fastenal p 500 index september 2008 following federal takeover fannie mae freddie mac removal index fiscal year 2018 salesforce reported earnings us 127 million annual revenue us 10.480 billion increase 24.9 previous fiscal cycle salesforce shares traded 131 per share market capitalization us 102.5 billion october 2018 salesforce ranked 285 2018 fortune 500 list largest united states companies revenue salesforce migrated dell servers advanced micro devices processors running linux sun fire e25k servers sparc processors running solaris 2008 company uses momentum platform message systems allow customers send large amounts email 2012 salesforce announced plans build data center uk handle european citizens personal data 2013 salesforce oracle announced nine-year partnership salesforce use oracle linux oracle exadata oracle database java platform power salesforce applications saas platform 2016 salesforce announced use amazon web services hosting countries restrictive data residency requirements salesforce data centers operating july 2017 first salesforce instance went live canada salesforce announcing enabled signing number canadian customers following list acquisitions salesforce november 2007 successful phishing attack salesforce employee compromised contact information number salesforce customers used send highly targeted phishing emails salesforce stated phisher tricked someone disclosing password intrusion stem security flaw salesforce.com application database phishing breach cited example crm industry needs greater security users threats spam crowd-sourced method building business contacts proven popular recruiters marketers sales professionals also raised questions privacy site database entered without permission person listed data.com however make easy remove business information request noted december 2009 techcrunch however recipients messages regard spam least one complaint receiving spam attempting remove one address noted 2017 def con salesforce director offensive security security engineer fired conference room floor front several attendees executive company giving talk word rapidly spread two speakers released event presentation initially signed company however salesforce management team unexplained sudden change heart hour event salesforce director offensive security turned phone prior presentation unable receive communication salesforce prior presentation reaction firings swift electronic frontier foundation providing representation fired employees members security community opining salesforce undermined credibility security community significant degree perceived security community n't top list things care presented meatpistol tool anticipated released open source time presentation salesforce continues hold back releasing code developers public terminated employees continued call company open-source software not-for-profit organization refugee immigrant center education legal services raices rejected us 250,000 philanthropic donation salesforce company contracts customs border patrol sic executive director raices jonathan ryan tweeted comes supporting oppressive inhumane illegal policies want clear right action stop reference rejected donation salesforce ceo marc benioff responded official statement company employees dont work cbp regarding separation families cbp customer follows tos dont agreement ice 'm proud men women protect serve country every day 'm proud ohana reported change acceptable-use policy salesforce barring customers using system sell semiautomatic guns firearms march 2019 salesforce faced lawsuit 50 anonymous women claiming victims survivors sex trafficking abuse rape alleges company profited knowingly facilitated sex trafficking web site backpage.com defunct since april 2018 lawsuit also pointed ironically salesforce publicly promoting anti-human trafficking campaign time work backpage 2009 response financial crisis 2007–2008 resulting decline venture funding salesforce began investing digital companies used integrated salesforce platform. ref name= peterson bi 8/18/2018 /ref eventually became salesforce ventures headed john somorjai since various funds created focus specific areas — september 2014 sfv set salesforce1 fund aimed start-ups creating applications primarily mobile phones december 2018 salesforce ventures announced launch japan trailblazer fund focused japanese startups august 2018 salesforce ventures reported investments totaling 1.2 billion 275 companies covering wide range business models including cloud storage cloudcraze artificial intelligence figure eight online fraud prevention forter accounting project software financialforce many areas five largest investments domo data-visualization software surveymonkey online survey software twilio cloud-communication dropbox cloud storage docusign secure e-signature company account nearly half portfolio. ref name= peterson bi 11/14/2018 /ref
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Distributed computing architecture
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readahead readahead system call linux kernel loads file contents page cache prefetches file subsequently accessed contents read main memory ram rather hard disk drive hdd resulting much lower file access latencies many linux distributions use readahead list commonly used files speed booting setup kernel booted profile boot parameter record file accesses bootup write new list files read later boot sequences make additional installed services start faster included default readahead list linux distributions use systemd readahead binary part boot sequence replaced systemd-readahead however support readahead removed systemd version 217 described unmaintained unable provide expected performance benefits certain experimental page-level prefetching systems developed improve performance
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Computer file systems
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typhoid adware typhoid adware type computer security threat uses man-in-the-middle attack inject advertising web pages user visits using public network like wifi hotspot researchers university calgary identified issue require affected computer adware installed order display advertisements computer researchers said threat yet observed described mechanism potential countermeasures environment threat work area non-encrypted wireless connection wireless internet cafe wifi hotspots typhoid adware would trick laptop recognize wireless provider inserts route wireless connection computer actual provider adware may insert various advertisements data stream appear computer browsing session way even video stream e.g. youtube may modified adware may run infested computer whose owner would see manifestations yet affect neighboring ones latter peculiarity named analogy typhoid mary mary mallon first identified person never experienced symptoms yet spread infection time running antivirus software affected computer useless since adware installed implemented proof concept described article written march 2010 daniel medeiros nunes de castro eric lin john aycock mea wang typhoid adware variant well-known man-in-the-middle attack researchers point number new important issues protection video content growing availability public wireless internet access well-monitored researchers say annoying advertisements tip iceberg serious danger may come e.g. promotions rogue antivirus software seemingly coming trusted source suggested countermeasures include approaches investigated earlier contexts
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Computer security
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river raid river raid vertically scrolling shooter designed programmed carol shaw published activision 1982 atari 2600 video game console million game cartridges sold activision later ported title atari 5200 colecovision intellivision consoles well commodore 64 ibm pcjr msx zx spectrum atari 8-bit family shaw atari 8-bit atari 5200 ports activision published less successful sequel 1988 without shaw involvement viewed top-down perspective player flies fighter jet river return raid behind enemy lines player jet move left right—it maneuver screen—but accelerate decelerate player jet crashes collides riverbank enemy craft jet runs fuel assuming fuel replenished player evades damage gameplay essentially unlimited player scores points shooting enemy tankers 30 points helicopters 60 points fuel depots 80 points jets 100 points bridges 500 points jet refuels flies fuel depot bridge marks end game level non-atari 2600 ports game add hot air balloons worth 60 points shot well tanks along sides river shoot player jet destroying bridges also serve game checkpoints player crashes plane start next jet last destroyed bridge time river raid provided inordinate amount non-random repeating terrain despite constrictive computer memory limits game program actually store sequence terrain objects instead procedural generation algorithm manifests employing linear feedback shift register hard-coded vector starting value hard-coded algorithm generates game world every time program executes enemy crafts ai however relies random number generator make enemy movement less predictable infoworld 1983 stated river raid might best atari 8-bit game year challenging vcs version superior others like caverns mars antic 1984 said atari 8-bit version identical 2600 original slightly spiffed ... game visuals deseret news 1984 called river raid one playable entertaining war games newspaper gave colecovision version four stars recommending console owners describing definite winner way game received award 1984 best action videogame certificate merit category 1984 best computer action game 5th annual arkie awards judges described provid ing brand non-stop excitement blast brigaders adore river raid first video game banned minors west germany federal department writings harmful young persons german bundesprüfstelle für jugendgefährdende schriften 1996 next generation listed atari 2600 version number 81 top 100 games time commenting nostalgia aside 2600 sucks ... game still great one main reason level design activision published relatively obscure river raid ii atari 2600 1988 sequel programmed david lubar based concept dan kitchen similar gameplay different landscape increased difficulty 1995 river raid published microsoft windows part activision atari 2600 action pack
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Computer architecture
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telecommunications access method telecommunications access method tcam access method ibm os/360 successors computer operating systems ibm system/360 later provides access terminals units within teleprocessing network tcam provides similar functionality qtam replaced access method initial version time sharing option tso advent ibm sna tcam eventually superseded vtam tcam said following enhancements qtam tcam consists message control program mcp zero application programs mcp handles communications terminals identifies input messages starts application programs process required similar concept much later internet service daemon inetd unix systems also similar qtam application programs called message processing programs mpp mcp assembled user installation set macros supplied ibm macros define lines terminals comprising system datasets required procedures used process received transmitted messages application programs incorporating logic process various messages supplied installation use standard os/360 data management macros codice_1 codice_2 either basic macros codice_3 codice_4 codice_5 queued macros codice_6 codice_7 use sam macros allows application programs tested batch processing environment tcam initially supported support 3270 terminals soon added
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Operating systems
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mobile-itx mobile-itx smallest 2009 x86 compliant motherboard form factor presented via technologies december 2009 motherboard size cpu module computer ports cpu module necessary use i/o carrier board design intended medical transportation military embedded markets mobile-itx form factor announced via technologies computex june 2007 motherboard size first prototypes design intended ultra-mobile computing smartphone umpc prototype boards shown date include x86-compliant 1 ghz via c7-m processor 256 512 megabytes ram modified version via cx700 chipset called cx700s interface cellular radio module demonstration boards contain cdma radio dc-dc electrical converter various connecting interfaces announcement ultra-mobile pc reference design shown running windows xp embedded
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Computer architecture
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yum software yellowdog updater modified yum free open-source command-line package-management utility computers running linux operating system using rpm package manager though yum command-line interface several tools provide graphical user interfaces yum functionality yum allows automatic updates package dependency management rpm-based distributions like advanced package tool apt debian yum works software repositories collections packages accessed locally network connection hood yum depends rpm packaging standard digital distribution software automatically uses hashes digisigs verify authorship integrity said software unlike app stores serve similar function neither yum rpm provide built-in support proprietary restrictions copying packages end-users yum implemented libraries python programming language small set programs provide command-line interface gui-based wrappers yum extender yumex also exist rewrite yum named dnf replaced yum default package manager fedora 22 dnf created improve yum several ways improved performance better resolution dependency conflicts easier integration software applications original package manager yellowdog updater yup developed 1999-2001 dan burcaw bryan stillwell stephen edie troy bengegerdes terra soft solutions leadership ceo kai staats back-end engine graphical installer yellow dog linux.. full rewrite yup yum evolved primarily update manage red hat linux systems used duke university department physics seth vidal michael stenner vidal continued contribute yum death durham north carolina bicycle accident 8 july 2013 2003 robert g. brown duke published documentation yum subsequent adopters included fedora centos many rpm-based linux distributions including yellow dog linux yum replaced original yup utility — last updated sourceforge 2001 2005 estimated use half linux market 2007 yum considered tool choice rpm-based linux distributions yum aimed address perceived deficiencies old apt-rpm restrictions red hat up2date package management tool yum superseded up2date red hat enterprise linux 5 later authors refer yum yellowdog update manager suggest update manager would appropriate basic knowledge yum often included requirement linux system-administrator certification gnu general public license yum allows free open-source software freely distributed modified without royalty terms license honored codice_1 perform operations 2.x versions yum feature additional interface programming extensions python allows behavior yum altered certain plug-ins installed default commonly installed package codice_2 contains commands use yum api many plugins graphical user interfaces known front-ends allow easier use yum packagekit yum extender yumex two examples information packages opposed packages known metadata metadata combined information package determine resolve possible dependencies among packages hope avoid situation known dependency hell separate tool codice_3 sets yum software repositories generating necessary metadata standard xml format sqlite metadata given -d option codice_4 tool formerly known yam help creation maintenance repositories yum xml repository built input many developers quickly became standard rpm-based repositories besides distributions use yum directly suse linux 10.1 added support yum repositories yast open build service repositories use yum xml repository format metadata yum automatically synchronizes remote meta data local client tools opting synchronize requested user automatic synchronization means yum fail due user failing run command correct interval
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Operating systems
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actionscript actionscript object-oriented programming language originally developed macromedia inc. later acquired adobe systems influenced hypertalk scripting language hypercard implementation ecmascript meaning superset syntax semantics language widely known javascript though originally arose sibling influenced hypertalk actionscript used primarily development websites software targeting adobe flash player platform used web pages form embedded swf files actionscript 3 also used adobe air system development desktop mobile applications language open-source specification offered free charge open source compiler part apache flex open source virtual machine mozilla tamarin available actionscript also used scaleform gfx development 3d video game user interfaces huds actionscript initially designed controlling simple 2d vector animations made adobe flash formerly macromedia flash initially focused animation early versions flash content offered interactivity features thus limited scripting capability later versions added functionality allowing creation web-based games rich internet applications streaming media video audio today actionscript suitable desktop mobile development adobe air use database applications basic robotics make controller kit flash mx 2004 introduced actionscript 2.0 scripting language suited development flash applications often possible save time scripting something rather animating usually also enables higher level flexibility editing since arrival flash player 9 alpha 2006 newer version actionscript released actionscript 3.0 version language intended compiled run version actionscript virtual machine completely re-written ground dubbed avm2 code written actionscript 3.0 generally targeted flash player 9 higher work previous versions time actionscript 3.0 executes 10 times faster legacy actionscript code due just-in-time compiler enhancements flash libraries used xml capabilities browser render rich content browser technology known asynchronous flash xml much like ajax adobe offers flex product line meet demand rich internet applications built flash runtime behaviors programming done actionscript actionscript 3.0 forms foundation flex 2 api actionscript started object-oriented language macromedia flash authoring tool developed adobe systems adobe flash first three versions flash authoring tool provided limited interactivity features early flash developers could attach simple command called action button frame set actions basic navigation controls commands play stop geturl gotoandplay release flash 4 1999 simple set actions became small scripting language new capabilities introduced flash 4 included variables expressions operators statements loops although referred internally actionscript flash 4 user manual marketing documents continued use term actions describe set commands 2000–2004 actionscript 1.0 release flash 5 september 2000 actions flash 4 enhanced named actionscript first time first version actionscript influences javascript ecma-262 third edition standard supporting said standard object model many core data types local variables may declared statement user-defined functions parameter passing return values also created notably actionscript could also typed text editor rather assembled choosing actions drop-down lists dialog box controls next release authoring tool flash mx corresponding player flash player 6 language remained essentially unchanged minor changes addition statement strict equality operator brought closer ecma-262-compliant two important features actionscript distinguish later versions loose type system reliance prototype-based inheritance loose typing refers ability variable hold type data allows rapid script development particularly well-suited small-scale scripting projects prototype-based inheritance actionscript 1.0 mechanism code reuse object-oriented programming instead keyword defines common characteristics class actionscript 1.0 uses special object serves prototype class objects common characteristics class defined class prototype object every instance class contains link prototype object 2003–2006 actionscript 2.0 next major revision language actionscript 2.0 introduced september 2003 release flash mx 2004 corresponding player flash player 7 response user demand language better equipped larger complex applications actionscript 2.0 featured compile-time type checking class-based syntax keywords allowed structured object-oriented programming approach code would still compiled actionscript 1.0 bytecode allowing used preceding flash player 6 well words class-based inheritance syntax layer top existing prototype-based system actionscript 2.0 developers could constrain variables specific type adding type annotation type mismatch errors could found compile-time actionscript 2.0 also introduced class-based inheritance syntax developers could create classes interfaces much would class-based languages java c++ version conformed partially ecmascript fourth edition draft specification 2006–today actionscript 3.0 june 2006 actionscript 3.0 debuted adobe flex 2.0 corresponding player flash player 9 actionscript 3.0 fundamental restructuring language much uses entirely different virtual machine flash player 9 contains two virtual machines avm1 code written actionscript 1.0 2.0 avm2 content written actionscript 3.0 actionscript 3.0 added limited support hardware acceleration directx opengl update language introduced several new features adobe air supports actionscript addition extended contents stage3d engine adobe developed number apis application programming interfaces available actionscript 3.0 also risen dramatically actionscript code free form thus may created whichever amount style whitespace author desires basic syntax derived ecmascript following code works compliant player creates text field depth 0 position 0 0 screen measured pixels 100 pixels wide high codice_1 parameter set string automatically displayed player writing external actionscript 2.0 class files example could written file named following actionscript 3.0 similar syntax actionscript 2.0 different set apis creating objects compare script previous actionscript 2.0 version var greet textfield new textfield greet.text hello world this.addchild greet minimal actionscript 3.0 programs may somewhat larger complicated due increased separation programming language flash ide presume following file package com.example actionscript 3 also used mxml files using apache flex framework actionscript primarily consists fundamental simple data types used create data types data types similar java data types since actionscript 3 complete rewrite actionscript 2 data types inheritances changed actionscript 2 top level data types actionscript 2 complex data types additional complex data types processor memory intensive consist many simple data types as2 data types actionscript 3 primitive prime data types actionscript 3 complex data types basic syntax order make empty object informal way types automatically put place unlike object-oriented languages actionscript makes distinction primitive types reference types actionscript variables reference types however objects belong primitive data types includes boolean number int uint string immutable variable supposedly primitive type e.g integer passed function altering variable inside function alter original variable new int object created inside function variable another primitive datatype e.g xml passed function altering variable inside function alter original variable well new xml object created data types assigned values literals reference actionscript pointer instance class reference stores memory address object – operations references follow value reference memory address object carry operation object objects actionscript accessed references instead accessed directly references object may removed using delete keyword removal actual objects data done flash player garbage collector checks existing references flash memory space none found reference made orphaned object removed memory reason memory management actionscript requires careful application development planning intermediate language compiled code flash microsoft .net swf file saved locally decompiled source code assets decompilers capable nearly full reconstruction original source file actual code used creation although results vary case-by-case basis opposition decompilers actionscript obfuscators introduced transform code form breaks decompiler output preserving functionality structure program higher-quality obfuscators implement lexical transformations identifier renaming control flow transformation data abstraction transformation collectively make harder decompilers generate output likely useful human less robust obfuscators insert traps decompilers obfuscators either cause decompiler software crash unexpectedly generate unintelligible source code following example actionscript 3.0 code generated decompiler program obfuscation code obfuscation code obfuscation
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Programming language topics
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mil-std-1750a mil-std-1750a 1750a formal definition 16-bit computer instruction set architecture isa including required optional components described military standard document mil-std-1750a 1980 since august 1996 inactive new designs addition core isa definition defines optional instructions fpu mmu importantly standard define implementation details 1750a processor 1750a supports 2 16-bit words memory core standard standard defines optional memory management unit allows 2 16-bit words memory using 512 page mapping registers i/o space defining separate instruction data spaces keyed memory access control instructions 16 bits although 16-bit extension standard computer 16 general purpose 16-bit registers 0 15 registers 1 15 used index registers registers 12 15 used base registers 16 registers could used stack pointer sjs urs instructions stack jump subroutine unstack return subroutine register 15 used stack pointer pshm popm instructions push multiple pop multiple computer instructions 16 32-bit binary arithmetic well 32 48 bit floating point i/o generally via i/o instructions xio vio separate 2 16-bit word address space may specialized bus mil-std-1750a define implementation details 1750a products available wide variety companies form component board system-level offerings implemented myriad technologies often advanced exotic respective periods e.g gaas ecl sos particular interest fact 1750a systems often offer high levels radiation hazardous environment protection making particularly suited military aviation space applications examples mil-std-1750a implementations include processors based mil-std-1750a usually programmed jovial high-level programming language defined united states department defense derived algol 58 lesser extent ada used also c compilers example cleanscape xtc-1750a older versions gnu gcc contain support mil-std-1750a declared obsolete version 3.1 removed subsequent versions addition ddc-i provides score integrated development environment ide ada95 c compilers tads tartan ada development system ada83 development environment targeting processors based mil-std-1750a u.s. air force defined standard order common computing architecture thereby reduce costs software computer systems military computing needs includes embedded tasks aircraft missile control systems well mundane general military computing needs advantages concept recognized outside usaf 1750a adopted numerous organizations european space agency nasa israeli aircraft industries many projects academia examples military aircraft using 1750a include fully space rated implementations make 1750a one types computers applicable use deep space applications example spacecraft use 1750a
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Computer architecture
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cloud elements cloud elements cloud api integration platform enables developers publish integrate aggregate manage apis unified platform using cloud elements developers quickly connect entire categories cloud services e.g. crm documents finance using uniform apis simply synchronize data multiple cloud services e.g salesforce zendesk quickbooks using innovative integration toolkit founded october 2012 cloud elements purpose built developers help organize world apis one-to-many approach ‘ visionary ’ api management according gartner inc. cloud elements headquartered denver co serves customers worldwide information found www.cloud-elements.com cloud elements accelerates api integrations innovative api hub technology providing uniform apis developers use easily make apis work together past years developers published millions unique apis one island data bigger challenge integrate apis together order synchronize data build new apps faster october 2012 cloud elements founded ceo mark geene cto vineet joshi vp product development atul barve three shared vision help developers build cloud applications faster lower cost ... since start company cloud elements grown 100 employees work together bring api integrations business sizes july 18 2014 company announced receiving 3.1 million series funding round investors include virginia-based grotech ventures california-based icon venture partners along galvanize ventures january 9 2017 company announced receiving 13 million funding reach series b funding led harbert growth partners allow cloud elements continue revenue increase nearly 40 percent quarter-over-quarter sapphire 2018 sap launched sap cloud platform open connectors purpose built api integration platform leveraging cloud elements catalog feature-rich connectors 150 leading enterprise saas applications cloud elements created offer cloud applications hubs provide restful apis json payloads cloud elements differentiates one-to-many api lets developers integrate maintain several services elements category within hubs connector “ elements ” provide variety advanced features built cloud elements ’ api integration platform puts data center company application ecosystem provide virtual data hub puts data model center integration strategy making easier manage integrate data additionally cloud elements provides normalized consistent apis across entire catalog elements eliminate need experts every endpoint finally platform allows service embedded app customers convenience virtual data resources vdr provide canonicalized view data objects eliminating need point-to-point mapping data every new application putting data models center application ecosystem enables management company ’ data enriched api models maintained cloud elements make easier map defined resources required endpoints traditional integration platforms point-to-point meaning new application needs connected directly every application ecosystem point-to-point integration best solution external integration embedded platform makes difficult scale effectively use ce ’ vdr created ui easily maps domain model cloud services use allow directly write integrations also offer vdr templates pre-written templates common resources used customers pre-mapping multiple endpoints
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Distributed computing architecture
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digital signal designation digital signal designation classification digital bit rates digital multiplex hierarchy used transport signals one location another telecommunications see sonet information
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Internet protocols
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list file copying software article provides list inbuilt third party file copying moving software utilities software used part computer file management explicitly move copy files data demand one location another storage device file copying fundamental operation data storage popular operating systems linux windows macos well smartphone operating systems android contain built-in file copying functions well command line cli graphical gui interfaces filing system copy move functions cases replaced supplemented third party software different extended improved functionality article lists inbuilt well external software designed purpose software designed copy clone image author entire storage devices cds dvds blu-ray disks hard drives storage device partitions back data copiers work storage devices logical unit general file managers utilities related file copying software please see examples comparable operating functionality seen across file copying programs generic differentiators functions software gizmo freeware published basic comparison reviews range well-known third party file copying software windows july 2012 fastcopy given top place reviewers highest speed also light system resources author states uses cache avoid slowing software win32 api c runtime rather mfc ultracopier recognised well-developed gui interface unstoppable copier well regarded niche copier designed best results damaged media files cost speed teracopy also mentioned also worth considering third-party file transfer software include
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Computer file systems
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handle system handle system corporation national research initiatives proprietary registry assigning persistent identifiers handles information resources resolving handles information necessary locate access otherwise make use resources handles used elsewhere computing handle system handles opaque encode information underlying resource bound metadata regarding resource consequently handles rendered invalid changes metadata system developed bob kahn corporation national research initiatives cnri original work funded defense advanced research projects agency darpa 1992 1996 part wider framework distributed digital object services thus contemporaneous early deployment world wide web similar goals handle system first implemented autumn 1994 administered operated cnri december 2015 new multi-primary administrator mpa mode operation introduced dona foundation administers system global handle registry accredits mpas including cnri international doi foundation system currently provides underlying infrastructure handle-based systems digital object identifiers dspace mainly used provide access scholarly professional government documents information resources cnri provides specifications source code reference implementations servers protocols used system royalty-free public license similar open source license thousands handle services currently running 1000 universities libraries also operation national laboratories research groups government agencies commercial enterprises receiving 200 million resolution requests per month handle system defined informational rfcs 3650 3651 3652 internet engineering task force ietf includes open set protocols namespace reference implementation protocols documentation software related information provided cnri dedicated website handles consist prefix identifies naming authority suffix gives local name resource similar domain names prefixes issued naming authorities one multi-primary administrators system upon payment fee must renewed annually naming authority may create number handles unique local names within assigned prefixes example handle first example handle handle.net software license codice_3 prefix assigned naming authority case handle.net codice_4 local name within namespace local name may consist characters unicode ucs-2 character set prefix also consists ucs-2 characters prefixes consist one naming authority segments separated periods representing hierarchy naming authorities thus example codice_5 naming authority prefix cnri codice_6 designates subordinate naming authority within 20 prefix examples top-level prefixes federated naming authorities dona foundation codice_7 doi handles codice_8 handles assigned itu codice_9 handles issued german gesellschaft für wissenschaftliche datenverarbeitung mbh göttingen gwdg scientific computing center university göttingen codice_10 coalition handle services – china older legacy prefixes issued cnri multi-primary administrator mpa structure instituted typically four five digits second example handle administered university leicester prefixes must registered global handle registry dona foundation approved registrar normally fee uses handles computing handle opaque encodes information underlying resource provides means retrieve metadata resource may contrasted uniform resource locator url may encode within identifier attributes resource protocol used access server holding resource server host name port number perhaps even location specifics name file server file system containing resource handle system specifics encoded handle found metadata handle bound metadata may include many attributes information resource locations forms available types access e.g free versus paid offered processing metadata determine resource accessed provision resource user performed separate step called resolution using resolver server may different ones involved exchanging handle metadata unlike urls may become invalid metadata embedded within becomes invalid handles become invalid need change locations metadata attributes change helps prevent link rot changes information resource location need reflected changes metadata rather changes every reference resource handle may administrator administration handles done distributed environment similar dns domain names name-to-value bindings may also secured via signatures verify data via challenge response verify transmission data allowing handles used trust management applications possible underlying information resource associated multiple handles two university libraries generate handles therefore possibly different sets metadata book handle system compatible domain name system dns require unlike persistent identifiers purls arks similar handles utilise domain names however unlike domain-name based approaches handles require separate prefix registration process handle servers separate domain name servers handles used natively expressed uniform resource identifiers uris namespace within info uri scheme example codice_1 may written uri codice_12 handle system namespaces digital object identifiers info uri namespaces right example codice_13 another way writing handle current revision doi handbook uri handle system namespaces define special presentation rules example digital object identifiers represent high percentage extant handles usually presented doi prefix codice_14 handles may also expressed uniform resource locators urls use http proxy server implementation handle system consists local handle services made one sites provide servers store specific handles global handle registry unique local handle service stores information prefixes also known naming authorities within handle system queried find specific handles stored local handle services within distributed system handle system website provides series implementation tools notably handle.net software handle.net client libraries handle clients embedded end user software e.g. web browser server software e.g. web server extensions already available adobe acrobat firefox handle client software libraries available c java applications developed specific add-on tools e.g. doi system interoperable network distributed handle resolver servers also known proxy server system linked global resolver one logical entity though physically decentralised mirrored users handle system technology obtain handle prefix created global handle registry global handle registry maintains resolves prefixes locally maintained handle services local handle service therefore resolve handle global resolver handles identifiers passed client query naming authority/prefix handle system global handle registry ghr ghr responds sending client location information relevant local handle service may consist multiple servers multiple sites query sent relevant server within local handle service local handle service returns information needed acquire resource e.g. url turned http re-direct note client already information appropriate lhs query initial query ghr omitted though original model handle system derives dealt management digital objects handle system mandate particular model relationships identified entities limited identifying digital objects non-digital entities may represented corresponding digital object purposes digital object management care needed definition objects relate non-digital entities established models aid definitions e.g. functional requirements bibliographic records frbr cidoc crm indecs content model applications found helpful marry framework handle application example advanced distributed learning adl initiative brings together handle system application existing standards distributed learning content using shareable content object reference model scorm digital object identifier doi system implementation handle system adopted together indecs framework deal semantic interoperability handle system also makes explicit importance organizational commitment persistent identifier scheme mandate one model ensuring commitment individual applications may choose establish sets rules social infrastructure ensure persistence e.g. used dspace application doi application handle system designed meet following requirements contribute persistence identifier string identifier resolution mechanism among objects currently identified handles journal articles technical reports books theses dissertations government documents metadata distributed learning content data sets handles used digital watermarking applications grid applications repositories although individual users may download use handle.net software independently many users found beneficial collaborate developing applications federation using common policy additional technology provide shared services one first persistent identifier schemes handle system widely adopted public private institutions proven several years see paradigm persistent identifiers handle system applications may use handles simple persistent identifiers commonly used resolve current url object may choose take advantage features support simultaneous return output multiple pieces current information related object defined data structures enables priorities established order multiple resolutions used handles therefore resolve different digital versions content mirror sites different business models pay vs. free secure vs. open public vs. private also resolve different digital versions differing content mix objects required distance-learning course thousands handle services running today located 71 countries 6 continents 1000 run universities libraries handle services run user federations national laboratories universities computing centers libraries national local government agencies contractors corporations research groups major publishers use handle system persistent identification commercially traded open access content implementation digital object identifier doi system number prefixes allow users assign handles growing stands 12,000 early 2014 six top-level global handle registry servers receive average 68 million resolution requests per month proxy servers known cnri passing requests system web receive average 200 million resolution requests per month statistics handle quick facts 2010 cnri itu international telecommunication union entered agreement collaborate use handle system digital object architecture generally working specific details collaboration april 2009 itu listed handle system emerging trend handle system handle.net global handle registry trademarks corporation national research initiatives cnri non-profit research development corporation usa handle system subject patents cnri licenses handle system technology public license similar open source license order enable broader use technology handle system infrastructure supported prefix registration service fees majority coming single prefix holders largest current single contributor international doi foundation public license allows commercial non-commercial use low cost patented technology reference implementation software allows software freely embedded systems products service agreement also available users intend provide identifier and/or resolution services using handle system technology handle system public license handle system represents several components long-term digital object architecture january 2010 cnri released general-purpose digital object repository software another major component architecture information release including protocol specification source code ready-to-use system clients utilities available
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Internet protocols
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typosquatting typosquatting also called url hijacking sting site fake url form cybersquatting possibly brandjacking relies mistakes typos made internet users inputting website address web browser user accidentally enter incorrect website address may led url including alternative website owned cybersquatter typosquatter url usually one five kinds similar victim site address e.g example.com similar abuses typosquatter site user may also tricked thinking fact real site use copied similar logos website layouts content spam emails sometimes make use typosquatting urls trick users visiting malicious sites look like given bank site instance several different reasons typosquatters buying typo domain many companies including verizon lufthansa lego garnered reputations aggressively chasing typosquatted names lego example spent roughly us 500,000 taking 309 cases udrp proceedings celebrities also frequently pursued domain names singers star athletes prominent examples include basketball player dirk nowitzki udrp dirkswish.com actress eva longoria udrp evalongoria.org since 2006 typosquatted variant google called 'goggle.com existed considered phishing/fraud site later ca 2011–2012 url redirected google.com 2018 check revealed redirect users adware pages another example corporate typosquatting yuube.com targeting youtube users programmed redirect malicious website page asks users add security check extension really malware similarly www.airfrance.com typosquatted www.arifrance.com diverting users website peddling discount travel examples equifacks.com equifax.com experianne.com experian.com tramsonion.com transunion.com three typosquatted sites registered comedian john oliver show last week tonight users trying visit popular internet-based game agar.io may misspell said url agor.io visiting site known produce jumpscare screamer popular creepypasta jeff killer flashed rapidly produced loud noise original site taken 2017 linked randomly-themed phishing websites united states 1999 anticybersquatting consumer protection act acpa contains clause section 3 amending 15 usc 1117 include sub-section 2 b ii aimed combatting typosquatting however april 17 2006 evangelist jerry falwell failed get u.s. supreme court review decision allowing christopher lamparello use www.fallwell.com relying plausible misspelling falwell name lamparello gripe site presents misdirected visitors scriptural references intended counter fundamentalist preacher scathing rebukes homosexuality lamparello v. falwell high court let stand 2005 fourth circuit finding use mark domain name gripe site criticizing markholder constitute cybersquatting uniform domain-name dispute-resolution policy udrp trademark holders file case world intellectual property organization wipo typosquatters cybersquatters general complainant show registered domain name identical confusingly similar trademark registrant legitimate interest domain name domain name used bad faith
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Web technology
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symbolics symbolics refers two companies now-defunct computer manufacturer symbolics inc. privately held company acquired assets former company continues sell maintain open genera lisp system macsyma computer algebra system symbolics.com domain originally registered march 15 1985 making first .com-domain world august 2009 sold napkin.com formerly xf.com investments symbolics inc. computer manufacturer headquartered cambridge massachusetts later concord massachusetts manufacturing facilities chatsworth california suburban section los angeles first ceo chairman founder russell noftsker symbolics designed manufactured line lisp machines single-user computers optimized run lisp programming language symbolics also made significant advances software technology offered one premier software development environments 1980s 1990s sold commercially open genera tru64 unix hp alpha lisp machine first commercially available workstation although word yet coined symbolics spinoff mit ai lab one two companies founded ai lab staffers associated hackers purpose manufacturing lisp machines lisp machines inc. although symbolics attracted hackers funding symbolics initial product lm-2 introduced 1981 repackaged version mit cadr lisp machine design operating system software development environment 500,000 lines written lisp microcode based mit lisp machine lisp software bundle later renamed zetalisp distinguish symbolics product vendors also licensed mit software symbolics zmacs text editor variant emacs implemented text-processing package named zwei acronym zwei eine initially eine acronym eine emacs recursive acronyms puns german words one eins eine two zwei lisp machine system software copyrighted mit licensed symbolics lmi 1981 symbolics shared copyrighted enhancements source code mit kept mit server according richard stallman symbolics engaged business tactic forced mit make symbolics copyrighted fixes improvements lisp machine os available symbolics mit symbolics competitors thereby choke competitor lmi time insufficient resources independently maintain develop os environment symbolics felt longer sufficient control product point symbolics began using copy software located company servers—while stallman says symbolics prevent lisp improvements flowing lisp machines inc. base symbolics made extensive improvements every part software continued deliver almost source code customers including mit however policy prohibited mit staff distributing symbolics version software others end open collaboration came end mit hacker community reaction stallman initiated gnu project make new community eventually copyleft gnu general public license would ensure hacker software could remain free software way symbolics played key albeit adversarial role instigating free software movement 1983 year later planned symbolics introduced 3600 family lisp machines code-named l-machine internally 3600 family innovative new design inspired cadr architecture sharing implementation details main processor 36-bit word divided 4 8 bits tags 32 bits data 28 bits memory address memory words 44 bits additional 8 bits used error-correcting code ecc instruction set stack machine 3600 architecture provided 4,096 hardware registers half used cache top control stack rest used microcode time-critical routines operating system lisp run-time environment hardware support provided virtual memory common machines class garbage collection unique original 3600 processor microprogrammed design like cadr built several large circuit boards standard ttl integrated circuits features common commercial computers class time cpu clock speed varied depending particular instruction executed typically around 5 mhz many lisp primitives could executed single clock cycle disk i/o handled multitasking microcode level 68000 processor known front-end processor fep started main computer handled slower peripherals normal operation ethernet interface standard equipment replacing chaosnet interface lm-2 3600 roughly size household refrigerator partly due size processor – cards widely spaced allow wire-wrap prototype cards fit without interference—and partly due limitations disk drive technology early 1980s 3600 introduction smallest disk could support zetalisp software 14 inches 356 mm across 3600s shipped 10½-inch fujitsu eagle 3670 3675 slightly shorter height essentially machine packed little tighter advent later disk drives could hold hundreds megabytes led introduction 3640 3645 roughly size two-drawer file cabinet later versions 3600 architecture implemented custom integrated circuits reducing five cards original processor design two large manufacturing cost savings performance slightly better old design 3650 first g machines known within company housed cabinet derived 3640s denser memory smaller disk drives enabled introduction 3620 size modern full-size tower pc 3630 fat 3620 room memory video interface cards 3610 lower priced variant 3620 essentially identical every way except licensed application deployment rather general development various models 3600 family popular ai research commercial applications throughout 1980s ai commercialization boom 1980s led directly symbolics success decade symbolics computers widely believed best platform available developing ai software lm-2 used symbolics-branded version complex space-cadet keyboard later models used simplified version right known simply symbolics keyboard featured many modifier keys used zmacs notably control/meta/super/hyper block feature complex symbol set space-cadet keyboard also contributing 3600 series success line bit-mapped graphics color video interfaces combined extremely powerful animation software symbolics graphics division headquartered westwood california stone throw major hollywood movie television studios made s-render s-paint software industry leaders animation business symbolics developed first workstations capable processing hdtv quality video enjoyed popular following japan 3600 – standard black-and-white monitor – made cameo appearance movie real genius company also referenced michael crichton novel jurassic park symbolics graphics division sold nichimen trading company early 1990s s-graphics software suite s-paint s-geometry s-dynamics s-render ported franz allegro common lisp sgi pc computers running windows nt today sold mirai izware llc continues used major motion pictures famously new line cinema lord rings video games military simulations symbolic 3600-series computers also used first front end controller computers connection machine massively parallel computers manufactured thinking machines inc. another mit spinoff based cambridge massachusetts connection machine ran parallel variant lisp initially used primarily ai community symbolics lisp machine particularly good fit front-end machine long time operating system n't name finally named genera around 1984 system included number advanced dialects lisp heritage maclisp pdp-10 included data types multiple-inheritance object-oriented programming features lisp dialect called lisp machine lisp mit symbolics used name zetalisp symbolics later wrote new software symbolics common lisp version common lisp standard late 1980s 2 years later planned ivory family single-chip lisp machine processors superseded g-machine 3650 3620 3630 systems ivory 390k transistor vlsi implementation designed symbolics common lisp using ns custom symbolics hardware design language hdl addressed 40-bit word 8 bits tag 32 bits data/address since addressed full words bytes half-words allowed addressing 4 gigawords gw 16 gigabytes gb memory increase address space reflected growth programs data semiconductor memory disk space became cheaper ivory processor 8 bits ecc attached word word fetched external memory chip actually 48 bits wide ivory instruction 18 bits wide two instructions plus 2-bit cdr code 2-bit data type instruction word fetched memory fetching two instruction words time memory enhanced ivory performance unlike 3600 microprogrammed architecture ivory instruction set still microcoded stored 1200 × 180-bit rom inside ivory chip initial ivory processors fabricated vlsi technology inc san jose california 2 µm cmos process later generations fabricated hewlett packard corvallis oregon 1.25 µm 1 µm cmos processes ivory stack architecture operated 4-stage pipeline fetch decode execute write back ivory processors marketed stand-alone lisp machines xl400 xl1200 xl1201 headless lisp machines nxp1000 add-in cards sun microsystems ux400 ux1200 apple macintosh macivory ii iii computers lisp machines ivory processors operated speeds two six times faster 3600 depending model revision ivory chip ivory instruction set later emulated software microprocessors implementing 64-bit alpha architecture virtual lisp machine emulator combined operating system software development environment xl machines sold open genera sunstone risc-like processor released shortly ivory designed ron lebel group symbolics westwood office however project canceled day supposed tape quickly commercial ai boom mid-1980s propelled symbolics success ai winter late 1980s early 1990s combined slowdown reagan star wars missile defense program darpa invested heavily ai solutions severely damaged symbolics internal war noftsker ceo board hired 1986 brian sear whether follow sun suggested lead focus selling software re-emphasize superior hardware ensuing lack focus noftsker sear fired company caused sales plummet fact combined ill-advised real estate deals company management boom years entered large long-term lease obligations california drove symbolics bankruptcy rapid evolution mass-market microprocessor technology pc revolution advances lisp compiler technology economics manufacturing custom microprocessors severely diminished commercial advantages purpose-built lisp machines 1995 lisp machine era ended symbolics hopes success symbolics continued enterprise limited revenues supported mainly service contracts remaining macivory ux-1200 ux-1201 machines still used commercial customers symbolics also sold virtual lisp machine vlm software dec compaq hp alpha-based workstations alphastation servers alphaserver refurbished macivory iis symbolics keyboards july 2005 symbolics closed chatsworth california maintenance facility reclusive owner company andrew topping died year current legal status symbolics software uncertain assortment symbolics hardware still available purchase august 2007 us dod still paying symbolics regular maintenance work march 15 1985 symbolics.com became first currently since still registered oldest registered .com domain internet symbolics.com domain purchased xf.com 2009 genera also featured extensive networking interoperability software seen point local area network system called chaosnet invented lisp machine predating commercial availability ethernet symbolics system supported chaosnet also one first tcp/ip implementations also supported decnet ibm sna network protocols dialnet protocol used phone lines modems genera would using hints distributed namespace database somewhat similar dns comprehensive like parts xerox grapevine automatically select best protocol combination use connecting network service application program user command would specify name host desired service example host name request terminal connection might yield connection tcp/ip using telnet protocol although many possibilities likewise requesting file operation copy file command might pick nfs ftp nfile symbolics network file access protocol one several others might execute request tcp/ip chaosnet whatever network suitable popular application program symbolics lisp machine icad computer-aided engineering system one first networked multi-player video games version spacewar developed symbolics lisp machine 1983 electronic cad software symbolics lisp machine used develop first implementation hewlett-packard precision architecture symbolics research development staff first mit later company produced number major innovations software technology symbolics graphics division sgd founded 1982 sold nichimen graphics 1992 developed s-graphics software suite s-paint s-geometry s-dynamics s-render symbolics genera software also used create computer animated movies used popular movies
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Programming language topics
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spamd spamd isc-licensed lightweight spam-deferral daemon written umbrella openbsd project spamd works directly smtp connections supports features greylisting minimising false positives compared system full-body analysis spamd designed work conjunction pf 4 fully functional posix system pf available i.e openbsd netbsd freebsd dragonfly bsd spamd useful preventing inbound spam reaching mail servers also used partial application level proxy ensure external mail servers connecting internal mail servers behave legitimately additionally spamd useful preventing outgoing spam systems may compromised control spammers used block spammers use following features
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Operating systems
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payment card industry security standards council payment card industry security standards council originally formed american express discover financial services jcb international mastercard visa inc. 7 september 2006 goal managing ongoing evolution payment card industry data security standard council claims independent various card vendors make council pci council formed body security standards known payment card industry data security standard pci dss standards consist twelve significant requirements including multiple sub-requirements contain numerous directives businesses may measure payment card security policies procedures guidelines also manage payment application data security standard pa-dss formerly referred payment application best practices pabp recently collaborated emvco provide security requirements testing procedures assessor training support emv 3-d secure v2.0 standard members pci security standards council currently consist five major payment brands visa mastercard american express discover jcb executives management pci ssc also filled employees aforementioned payment brands interested parties participate development pci security standards registration participating organization participants organized special interest groups tasked recommending revisions development various security standards maintained council
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Computer security
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elcomsoft elcomsoft co.ltd privately owned software company headquartered moscow russia since establishment 1990 company working computer security programs main focus password system recovery software july 16 2001 dmitry sklyarov russian citizen employed elcomsoft time visiting united states def con arrested jailed allegedly violating united states dmca law writing elcomsoft advanced ebook processor software landmark court case ensued setting precedents attracting much public attention protest december 17 2002 elcomsoft found guilty four charges dmca bruce chizen ceo adobe systems say cnet looking back 20/20 wish could better communication elcomsoft dmitry sklyarov eff electronic frontier foundation whole thing went public 'm sorry n't able think could resolved lot issues thunder tables® company technology developed ensure guaranteed recovery microsoft word microsoft excel documents protected 40-bit encryption technology first appeared 2007 employs time–memory tradeoff method build pre-computed hash tables open corresponding files matter seconds instead days tables take around 4gb far technology used two password recovery programs advanced office password breaker advanced pdf password recovery 7,599,492 fast cryptographic key recovery system method 7,783,046 probabilistic cryptographic key identification deterministic result 7,787,629 use graphics processors parallel math co-processors password recovery 7,809,130 password recovery system method 7,929,707 use graphics processors parallel math co-processors password recovery 2009 elcomsoft released tool takes wpa/wpa2 hash codes uses brute-force methods guess password associated wireless network brute force attack carried testing passwords known ssid network wpa/wpa2 hash code captured passwords tested generated dictionary using various mutation genetic algorithm methods including case mutation password password password etc year mutation password password1992 password67 etc many mutations try guess correct password advantages using methods traditional ones rainbow tables numerous rainbow tables large size amount ssid/password combinations saved take long time traverse large numbers passwords per ssid reliant ssid common one rainbow table already listed hash codes common ones include linksys belkin54g etc. ewsa however uses relatively small dictionary file megabytes versus dozens gigabytes common rainbow tables creates passwords fly needed rainbow tables tested captured wpa/wpa2 hash code via computer processor relatively low numbers simultaneous processes possible ewsa however use computer processor 32 logical cores 8 gpus many cuda cores nvidia stream processors ati november 30 2010 elcomsoft announced encryption system used canon cameras ensure pictures exif metadata altered flawed fixed day dmitry sklyarov gave presentation confidence 2.0 conference prague demonstrating flaws among others showed image astronaut planting flag soviet union moon images pass canon authenticity verification
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Computer security
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sesam database sesam sql server relational database system originally developed siemens whose role developer successively succeeded siemens nixdorf informationssysteme sni fujitsu siemens computers fujitsu technology solutions runs bs2000/osd mainframe clients running bs2000/osd unix systems solaris linux microsoft windows supported
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Databases
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nslu2 nslu2 network storage link usb 2.0 disk drives network-attached storage nas device made linksys introduced 2004 discontinued 2008 makes usb flash memory hard disks accessible network using smb protocol also known windows file sharing cifs superseded mainly nas200 enclosure type storage link another sense wrt600n wrt300n/350n combine wi-fi router storage link device runs modified version linux default formats hard disks ext3 filesystem firmware upgrade linksys adds ability use ntfs fat32 formatted drives device better windows compatibility device web interface various advanced features configured including user group permissions networking options device two usb 2.0 ports connecting hard disks uses arm-compatible intel xscale ixp420 cpu models manufactured prior around april 2006 linksys underclocked processor 133 mhz though simple hardware modification remove restriction possible later models circa may 2006 clocked rated speed 266 mhz device includes 32 mb sdram 8 mb flash memory also 100 mbit/s ethernet network connection nslu2 fanless making completely silent stock device runs customised version linux linksys required release source code per terms gnu general public license due availability source code nslu2 use well-documented commodity components relatively low price several community projects centered around including hardware modifications alternative firmware images alternative operating systems varying degrees reconfiguration unofficial hardware modifications include two main replacement firmware images available device first unslung based official linksys firmware improvements features added optware packages available expand functionality slugos/be formerly openslug based openembedded framework slugos/be allows users re-flash device minimal linux system including ssh server allow remote access installed operating system must moved attached hard disk due lack space available flash memory done wide range additional packages available installed internet repository also possible run openwrt debian gentoo freebsd netbsd openbsd ubuntu device ability run unrestricted operating system device opens whole new range uses common uses web server mail server daap server itunes xlink kai upnp av mediaservers bittorrent client freeswitch asterisk pbx network router attachment usb network interface/usb modem german programmer boris pasternak developed weather server program/server meteohub inexpensive way gather weather sensor data personal weather stations pws allow posted number online weather services including weather underground weatherbug citizens weather observation program cwop many others nslu2 unslung firmware interfaced topfield tf5800 personal video recorder pvr allow electronic programme guide epg automatically downloaded internet transferred pvr nslu2 innovative networking reader award tom hardware 2004 awards
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Operating systems
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list security hacking incidents timeline computer security hacker history covers important noteworthy events history security hacking cracking
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Computer security
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commodity computing commodity computing also known commodity cluster computing involves use large numbers already-available computing components parallel computing get greatest amount useful computation low cost computing done commodity computers opposed high-cost superminicomputers boutique computers commodity computers computer systems manufactured multiple vendors incorporating components based open standards systems said based commodity components since standardization process promotes lower costs less differentiation among vendors products standardization decreased differentiation lower switching exit cost given vendor increasing purchasers leverage preventing lock-in governing principle commodity computing preferable low-performance low-cost hardware working parallel scalar computing e.g amd x86 cisc fewer high-performance high-cost hardware items e.g ibm power7 sun-oracle sparc risc point number discrete systems cluster greater mean time failures mtbf hardware platform matter reliable fault tolerance must built controlling software purchases optimized cost-per-unit-of-performance absolute performance-per-cpu cost first computers large expensive proprietary move towards commodity computing began dec introduced pdp-8 1965 computer relatively small inexpensive enough department could purchase one without convening meeting board directors entire minicomputer industry sprang supply demand 'small computers like pdp-8 unfortunately many different brands minicomputers stand software little hardware compatibility brands first general purpose microprocessor introduced 1974 immediately began chipping away low end computer market replacing embedded minicomputers many industrial devices process accelerated 1977 introduction first commodity-like microcomputer apple ii development visicalc application 1979 microcomputers broke factory began entering office suites large quantities still back door ibm pc introduced 1981 immediately began displacing apple iis corporate world commodity computing know today truly began compaq developed first true ibm pc compatible pc-compatible microcomputers began coming big companies front door commodity computing well established 1980s microcomputers began displacing larger computers serious way first price key justification late 1980s early 1990s vlsi semiconductor technology evolved point microprocessor performance began eclipse performance discrete logic designs traditional designs limited speed-of-light delay issues inherent cpu larger single chip performance alone began driving success microprocessor-based systems mid-1990s nearly computers made based microprocessors majority general purpose microprocessors implementations x86 instruction set architecture although time every traditional computer manufacturer proprietary micro-based designs manufacturers non-commodity computer systems today today fewer fewer general business computing requirements met off-the-shelf commodity computers likely low-end supermicrocomputer genre continue pushed upward increasingly powerful commodity microcomputers
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Computer architecture
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multiple access collision avoidance wireless multiple access collision avoidance wireless macaw slotted medium access control mac protocol widely used ad hoc networks furthermore foundation many mac protocols used wireless sensor networks wsn ieee 802.11 rts/cts mechanism adopted protocol uses rts-cts-ds-data-ack frame sequence transferring data sometimes preceded rts-rrts frame sequence view provide solution hidden node problem although protocols based macaw s-mac use carrier sense addition rts/cts mechanism macaw make use carrier sense assume node data transfer node b. node initiates process sending request send frame rts node b destination node node b replies clear send frame cts receiving cts node sends data successful reception node b replies acknowledgement frame ack node send one data fragment wait random time successful data transfer compete adjacent nodes medium using rts/cts mechanism node overhearing rts frame example node f node e illustration refrains sending anything cts received waiting certain time captured rts followed cts maximum waiting time rts propagation time destination node turnaround time node node c node e overhearing cts frame refrains sending anything time data frame ack received solving hidden terminal problem plus random time rts cts frames contain information length data frame hence node uses information estimate time data transmission completion sending long data frame node sends short data-sending frame ds provides information length data frame every station overhears frame knows rts/cts exchange successful overhearing station node f might received rts ds cts defers transmissions ack frame received plus random time sum successful data transfer b consists following sequence frames macaw non-persistent slotted protocol meaning medium busy example cts message station waits random time start time slot sending rts results fair access medium example nodes b c data fragments send busy period chance access medium since transmission range node unaware ongoing data transfer node node b. node data send node c transmission range node d. initiates process sending rts frame node c. node c already deferred transmission completion current data transfer node node b avoid co-channel interference node b hence even though receives rts node reply back cts node assumes rts successful collision hence proceeds back using exponential backoff algorithm multiple data fragments send instant node successfully initiate data transfer small gaps node completed data transfer completion node b next cts node next data transfer request however due node backoff time period probability capture medium small time interval high increase per-node fairness macaw introduces new control message called request request send rrts node c reply earlier due ongoing transmission node node b sends rrts message node next contention period recipient rrts node immediately responds rts normal message exchange commenced nodes overhearing rrts defer two time slots long enough hear successful rts–cts exchange occurs summarize transfer may case consist following sequence frames node c additional back-off algorithms developed researched improve performance basic principle based use sequencing techniques node wireless network maintains counter limits number attempts less equal sequence number use wireless channel states control access probabilities node good channel state higher probability contention success reduces number collisions macaw generally solve exposed terminal problem assume node g data send node f example node g information ongoing data transfer b initiates process sending rts signal node f. node f transmission range node hear rts node g since exposed co-channel interference node g assumes rts successful collision hence backs tries case solution provided rrts mechanism improve situation much since data frames sent b rather long compared frames probability f exposed transmission rather high node f idea node interested initiating data transfer g happens transmit rts transmissions furthermore macaw might behave normally multicasting
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Internet protocols
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imdos imdos modified version cp/m operating system intel 8080 processors used ims associates inc. ims imsai 8080 personal computer since mits would license operating system manufacturers ims approached gary kildall paid fixed fee 25,000 non-exclusive cp/m license imdos introduced interrupt-driven devices tree-structured directories advances cp/m
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Operating systems
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artificial grammar learning artificial grammar learning agl paradigm study within cognitive psychology linguistics goal investigate processes underlie human language learning testing subjects ability learn made-up grammar laboratory setting developed evaluate processes human language learning also utilized study implicit learning general sense area interest typically subjects ability detect patterns statistical regularities training phase use new knowledge patterns testing phase testing phase either use symbols sounds used training phase transfer patterns another set symbols sounds surface structure many researchers propose rules artificial grammar learned implicit level since rules grammar never explicitly presented participants paradigm also recently utilized areas research language learning aptitude structural priming investigate brain structures involved syntax acquisition implicit learning apart humans paradigm also used investigate pattern learning species e.g cottontop tamarins starlings half century ago george a. miller established paradigm artificial grammar learning order investigate influence explicit grammar structures human learning designed grammar model letters different sequences research demonstrated easier remember structured grammar sequence random sequence letters explanation learners could identify common characteristics learned sequences accordingly encode memory set predicted subjects could identify letters likely appear together sequence repeatedly letters would subjects would use information form memory sets memory sets served participants strategy later memory tests reber doubted miller explanation claimed participants could encode grammar rules productive memory sets able verbalize strategy detail conducted research led development modern agl paradigm research used synthetic grammar learning model test implicit learning agl became used tested model field original paradigm developed miller participants asked memorize list letter strings created artificial grammar rule model test phase participants told set rules behind letter sequences memorized instructed categorize new letter strings based set rules previously exposed classified new letter strings grammatical constructed grammar rule vs. randomly constructed sequences subjects correctly sorted new strings chance level could inferred subjects acquired grammatical rule structure without explicit instruction rules reber found participants sorted new strings chance level reported using strategies sorting task could actually verbalize strategies subjects could identify strings grammatically correct could identify rules composed grammatical strings research replicated expanded upon many others conclusions studies congruent reber hypothesis implicit learning process done intentional learning strategies studies also identified common characteristics implicitly acquired knowledge modern agl paradigm used investigate explicit implicit learning although often used test implicit learning typical agl experiment participants required memorize strings letters previously generated specific grammar length strings usually ranges 2-9 letters per string example grammar shown figure 1 figure 1 example artificial grammar rule order compose grammatically ruleful string letters according predetermined grammar rule subject must follow rules pairing letters represented model figure 1 observing violation grammatical rule system composes string considered unruleful randomly constructed string case standard agl implicit learning task subjects told strings based specific grammar instead simply given task memorize letter strings memory learning phase subjects told letter strings presented learning phase based specific rules explicitly told rules test phase subjects instructed categorize new letter strings ruleful unruleful dependent variable usually measured percentage correctly categorized strings implicit learning considered successful percentage correctly sorted strings significantly higher chance level significant difference found indicates existence learning process involved memorizing presented letter strings mechanism behind implicit learning hypothesized occur people engage artificial grammar learning statistical learning specifically bayesian learning bayesian learning takes account types biases prior probability distributions individuals contribute outcome implicit learning tasks biases thought probability distribution contains probability possible hypothesis likely correct due structure bayesian model inferences output model form probability distribution rather single probable event output distribution posterior probability distribution posterior probability hypothesis original distribution probability hypothesis true given data probability data given hypothesis true bayesian model learning fundamental understanding pattern detection process involved implicit learning therefore mechanisms underlie acquisition artificial grammar learning rules hypothesized implicit learning grammar involves predicting co-occurrences certain words certain order example dog chased ball sentence learned grammatically correct implicit level due high co-occurrence chase one words follow dog sentence like dog cat ball implicitly recognized grammatically incorrect due lack utterances contain words paired specific order process important teasing apart thematic roles parts speech grammatical processing see grammar labeling thematic roles parts speech explicit identification words parts speech implicit traditional approaches agl claim stored knowledge obtained learning phase abstract approaches argue stored knowledge concrete consists exemplars strings encountered learning phase chunks exemplars case assumed information stored memory retrieved test phase used aid decisions letter strings 3 main approaches attempt explain agl phenomena research amnesia patients suggests dual factor approach may accurate model series experiments amnesiac patients support idea agl involves abstract concepts concrete exemplars amnesiacs able classify stimuli grammatical vs. randomly constructed well participants control group able successfully complete task amnesiacs able explicitly recall grammatical chunks letter sequence control group able explicitly recall performing task grammar rules different sequence letters previously tested amnesiacs control group able complete task although performance better task completed using set letters used training results experiment support dual factor approach artificial grammar learning people use abstract information learn rules grammars use concrete exemplar-specific memory chunks since amnesiacs unable store specific chunks memory completed task using abstract set rules control group able store specific chunks memory evidenced recall store examples memory later reference agl research criticized due automatic question agl considered automatic process encoding see encoding memory performance automatic sense occurring without conscious monitoring without conscious guidance performer ’ intentions case agl claimed implicit learning automatic process due fact done intention learning specific grammar rule complies classic definition automatic process fast unconscious effortless process may start unintentionally aroused continues without ability stop ignore consequences definition challenged many times alternative definitions automatic process given reber presumption agl automatic could problematic implying unintentional process automatic process essence focusing agl tests issues need addressed process complex contains encoding recall retrieval encoding retrieval could interpreted automatic processes since encoded learning stage necessary task intentionally performed test stage researchers need differentiate implicitness referring process learning knowledge encoding also referring performance test phase knowledge retrieval knowledge encoded training may include many aspects presented stimuli whole strings relations among elements etc. contribution various components performance depends specific instruction acquisition phase requirements retrieval task therefore instructions every phase important order determine whether stage require automatic processing phase evaluated automaticity separately one hypothesis contradicts automaticity agl mere exposure effect mere exposure effect increased affect towards stimulus result nonreinforced repeated exposure stimulus results 200 experiments effect indicate positive relationship mean goodness rating frequency stimulus exposure stimuli experiments included line drawings polygons nonsense words types stimuli used agl research experiments exposed participants stimulus 25 times following exposure participants asked rate degree stimulus suggested good vs. bad effect 7-point scale addition main pattern results also found several experiments participants rated higher positive affect previously exposed items novel items since implicit cognition reference previous study episodes effects affect ratings observed processing stimuli truly implicit results experiments suggests different categorization strings may occur due differences affect associated strings due implicitly learned grammar rules since advent computers artificial intelligence computer programs adapted attempt simulate implicit learning process observed agl paradigm ai programs first adapted simulate natural artificial grammar learning used following basic structure early model ai grammar learning wolff snpr system program acquires series letters pauses punctuation words sentences program examines string subsets looks common sequences symbols defines chunks terms sequences chunks akin exemplar-specific chunks described agl model acquires chunks exposure chunks begin replace sequences unbroken letters chunk precedes follows common chunk model determines disjunctive classes terms first set example model encounters the-dog-chased the-cat-chased classifies dog cat members class since precede chase model sorts chunks classes explicitly define groups e.g. noun verb early ai models grammar learning ignored importance negative instances grammar effect grammar acquisition also lacking ability connect grammatical rules pragmatics semantics newer models attempted factor details unified model attempts take factors account model breaks grammar according cues languages mark case roles using five possible cue types word order case marking agreement intonation verb-based expectation see grammar influence cue language grammar determined cue strength cue validity values determined using formula except cue strength defined experimental results cue validity defined corpus counts language databases formula cue strength/validity follows cue availability proportion times cue available times needed cue reliability proportion times cue correct total occurrences cue incorporating cue reliability along cue availability unified model able account effects negative instances grammar since takes accuracy frequency account result also accounts semantic pragmatic information since cues produce grammar appropriate context low cue strength cue validity macwhinney model also simulates natural grammar learning attempts model implicit learning processes observed agl paradigm contemporary studies agl attempted identify structures involved acquisition grammar implicit learning agrammatic aphasic patients see agrammatism tested agl paradigm results show breakdown language agrammatic aphasia associated impairment artificial grammar learning indicating damage domain-general neural mechanisms sub serving language sequential learning de vries barth maiworm knecht zwitserlood flöel found electrical stimulation broca area enhances implicit learning artificial grammar direct current stimulation may facilitate acquisition grammatical knowledge finding potential interest rehabilitation aphasia petersson vasiliki hagoort examine neurobiological correlates syntax processing structured sequences comparing fmri results artificial natural language syntax argue chomsky hierarchy directly relevant neurobiological systems agl testing
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Computational linguistics
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tcp tuning tcp tuning techniques adjust network congestion avoidance parameters transmission control protocol tcp connections high-bandwidth high-latency networks well-tuned networks perform 10 times faster cases however blindly following instructions without understanding real consequences hurt performance well bandwidth-delay product bdp term primarily used conjunction tcp refer number bytes necessary fill tcp path i.e equal maximum number simultaneous bits transit transmitter receiver high performance networks large bdps give practical example two nodes communicating geostationary satellite link round-trip delay time round-trip time rtt 0.5 seconds bandwidth 10 gbit/s 0.5×10 bits i.e. 5 gbit 625 mb unacknowledged data flight despite much lower latencies satellite links even terrestrial fiber links high bdps link capacity large operating systems protocols designed recently years ago networks slower tuned bdps orders magnitude smaller implications limited achievable performance original tcp configurations supported tcp receive window size buffers 65,535 64 kib 1 bytes adequate slow links links small rtts larger buffers required high performance options described buffering used throughout high performance network systems handle delays system general buffer size need scaled proportionally amount data flight time high performance applications sensitive network delays possible interpose large end end buffering delays putting intermediate data storage points end end system use automated scheduled non-real-time data transfers get data final endpoints maximum achievable throughput single tcp connection determined different factors one trivial limitation maximum bandwidth slowest link path also less obvious limits tcp throughput bit errors create limitation connection well rtt computer networking rwin tcp receive window amount data computer accept without acknowledging sender sender received acknowledgement first packet sent stop wait wait exceeds certain limit may even retransmit tcp achieves reliable data transmission even packet loss network windowing limit throughput tcp transmits data window size waiting acknowledgements full bandwidth network may always get used limitation caused window size calculated follows formula_1 rwin tcp receive window rtt round-trip time path given time window advertised receive side tcp corresponds amount free receive memory allocated connection otherwise would risk dropping received packets due lack space sending side also allocate amount memory receive side good performance even data sent network sending side must hold memory acknowledged successfully received case would retransmitted receiver far away acknowledgments take long time arrive send memory small saturate block emission simple computation gives optimal send memory size receive memory size given packet loss occurs network additional limit imposed connection case light moderate packet loss tcp rate limited congestion avoidance algorithm limit calculated according formula mathis et al formula_2 mss maximum segment size p probability packet loss packet loss rare tcp window becomes regularly fully extended formula n't apply number extensions made tcp years increase performance fast high-rtt links long fat networks lfns tcp timestamps rfc 1323 play double role avoid ambiguities due 32-bit sequence number field wrapping around allow precise rtt estimation presence multiple losses per rtt improvements becomes reasonable increase tcp window beyond 64 kb done using window scaling option rfc 1323 tcp selective acknowledgment option sack rfc 2018 allows tcp receiver precisely inform tcp sender segments lost increases performance high-rtt links multiple losses per window possible path mtu discovery avoids need in-network fragmentation increasing performance presence packet loss
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Internet protocols
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university bristol university bristol simply referred bristol university abbreviated bris post-nominal letters uob red brick research university located bristol united kingdom received royal charter 1909 although like university west england university bath trace roots merchant venturers technical college founded school 1595 society merchant venturers key predecessor institution university college bristol existence since 1876 bristol organised six academic faculties composed multiple schools departments running 200 undergraduate courses largely situated tyndalls park area city university total income £642.7 million 2017/18 £164.0 million research grants contracts. ref name= bristol financial statement 17/18 /ref largest independent employer bristol university bristol ranked 44th qs world university rankings 2018 ranked amongst top 10 uk universities qs arwu highly selective institution average 6.4 sciences faculty 13.1 medicine dentistry faculty applicants undergraduate place ranked 9th uk amongst multi-faculty institutions quality gpa research research power 2014 research excellence framework current academics include 21 fellows academy medical sciences 13 fellows british academy 13 fellows royal academy engineering 44 fellows royal society university associated 13 nobel laureates throughout history including paul dirac sir william ramsay cecil frank powell sir winston churchill dorothy hodgkin hans albrecht bethe max delbrück gerhard herzberg sir nevill francis mott sir paul nurse harold pinter jean-marie gustave le clézio recently 2015 economics nobel prize winner angus deaton bristol member russell group research-intensive british universities european-wide coimbra group worldwide universities network university previous vice-chancellor eric thomas chairman 2005 2007 addition university holds erasmus charter sending 500 students per year partner institutions europe earliest antecedent university engineering department merchant venturers technical college founded school early 1595 became engineering faculty bristol university university also preceded bristol medical school 1833 university college bristol founded 1876 first lecture attended 99 students university able apply royal charter due financial support wills fry families made fortunes tobacco plantations chocolate respectively wills family made vast fortune tobacco industry gave generously city university royal charter gained may 1909 288 undergraduates 400 students entering university october 1909 henry overton wills iii became first chancellor university college first institution country admit women basis men however women forbidden take examinations medicine 1906 since founding university 1909 grown considerably one largest employers local area although smaller student numbers nearby university west england bristol campus spread considerable geographic area activities however concentrated area city centre referred university precinct member russell group research-led uk universities coimbra group leading european universities worldwide universities network wun founding university college 1876 government support began 1889 mergers bristol medical school 1893 merchant venturers technical college 1909 funding allowed opening new medical school engineering school—two subjects remain among university greatest strengths 1908 gifts fry wills families particularly £100,000 henry overton wills iii £6m today money provided endow university bristol west england provided royal charter could obtained within two years december 1909 king granted charter erected university bristol henry wills became first chancellor conwy lloyd morgan first vice-chancellor wills died 1911 tribute sons george harry built wills memorial building starting 1913 finally finishing 1925 today houses parts academic provision earth sciences law graduation ceremonies held great hall wills memorial building grade ii* listed building 1920 george wills bought victoria rooms endowed university students union building houses department music grade ii* listed building point foundation university required provide local community mission behind creation department extra-mural adult education 1924 provide courses local community mission continues today new admissions policy specifically caters 'bs postcode area bristol among famous names associated bristol early period paul dirac graduated 1921 degree engineering obtaining second degree mathematics 1923 cambridge subsequent pioneering work quantum mechanics awarded 1933 nobel prize physics later 1920s h.h wills physics laboratory opened ernest rutherford since housed several nobel prize winners cecil frank powell 1950 hans albrecht bethe 1967 sir nevill francis mott 1977 laboratory stands site today close bristol grammar school city museum sir winston churchill became university third chancellor 1929 serving university capacity 1965 succeeded richard haldane held office 1912 following death henry wills world war ii wills memorial bombed destroying great hall organ housed along 7,000 books removed king college london safe keeping since restored former glory complete oak panelled walls new organ 1946 university established first drama department country year bristol began offering special entrance exams grants aid resettlement servicemen returning home student numbers continued increase faculty engineering eventually needed new premises become queen building 1955 substantial building housed university engineers 1996 department electrical engineering department computer science moved road new merchant venturers building make space rapidly expanding fields today queen building caters teaching needs faculty provides academic space heavy engineering subjects civil mechanical aeronautical unprecedented growth 1960s particularly undergraduate numbers student union eventually acquired larger premises new building clifton area city 1965 building spacious victoria rooms given department music new union provides many practice performance rooms specialist rooms well three bars bar 100 mandela also known ar2 avon gorge whilst spacious union building thought many ugly character compared architecture rest clifton area mentioned bbc poll find worst architectural eyesores britain university proposed relocating union central location part development 'masterplan recently plans redevelopment current building proposed 1960s time considerable student activism united kingdom bristol exception 1968 many students marched support anderson report called higher student grants discontent culminated 11-day sit-in senate house administrative headquarters university series chancellors vice-chancellors led university decades henry somerset 10th duke beaufort taking churchill chancellor 1965 succeeded dorothy hodgkin 1970 spent next 18 years office age mass higher education dawned bristol continued build student numbers various undergraduate residences repeatedly expanded recently postgraduate residences constructed recent ventures funded run external companies agreement university since 1988 three chancellors sir jeremy morse chairman lloyds bank handed 2003 brenda hale first female law lord sir paul nurse succeeded lady hale chancellor 1 january 2017 one centres deaf studies united kingdom established bristol 1981 followed 1988 norah fry centre research learning difficulties also 1988 2004 students union agm voted disaffiliate national union students nus occasions however subsequent referendum students reversed decision bristol remains affiliated nus 2002 university involved argument press intrusion details then-prime minister tony blair son application university published national newspapers number postgraduate students grown particularly numbers pursuing taught master degrees eventually became need separate representation university bodies postgraduate union pgu established 2000 universities increasingly expected exploit intellectual property generated research activities 2000 bristol established research enterprise division red cause particularly technology-based businesses 2001 university signed 25-year research funding deal ip2ipo intellectual property commercialisation company 2007 research activities expanded opening advanced composites centre innovation science accis bristol institute public affairs bipa 2002 university opened new centre sports exercise health heart university precinct cost local residents also able use facilities expansion teaching research activities continues 2004 faculty engineering completed work bristol laboratory advanced dynamics engineering blade £18.5m project intended study dynamics advanced facility europe built extension queen building officially opened queen elizabeth ii march 2005 january 2005 school chemistry awarded £4.5m higher education funding council england create bristol chemlabs centre excellence teaching learning cetl additional £350k announced capital part project february 2006 bristol chemlabs stands bristol chemical laboratory sciences chemistry cetl uk september 2009 saw opening university centre nanoscience quantum information £11 million building known quietest building world technologically sophisticated features self-cleaning glass advanced research quantum computing nanotechnology materials disciplines undertaken building also plan significantly redevelop centre university precinct coming years first step began september 2011 start construction state-of-the-art life sciences building time heavy financial pressures universities £50 million project clear statement bristol committed world class research teaching facilities 2018 building work underway fry building building caught fire university regarded elitist commentators taking 41 undergraduate students non-state schools according recent 2009/2010 figures despite fact pupils make 7 population 18 16+ year old pupils across uk intake state school pupils bristol lower many oxbridge colleges high ratio undergraduates non-state school led tension university late february early march 2003 bristol became embroiled row admissions policies private schools threatening boycott based claims effort improve equality access university discriminating students claims hotly denied university august 2005 following large-scale survey independent schools council publicly acknowledged evidence bias applicants schools represented university new admissions policy lays considerable detail basis greater lesser weight may given particular parts applicant backgrounds – particular account may taken school applicant hails new policy also encourages greater participation locally resident applicants university bristol buildings date pre-charter days university college bristol buildings designed charles hansom younger brother joseph hansom joseph inventor hansom cab buildings suffered built stages due financial pressure george oatley added tower memory albert fry still seen university road first large scale building project university bristol undertook gaining charter wills memorial building hoped would symbol academic permanence university memorial chief benefactor university henry overton wills requested architect george oatley building built last least 400 years site purchased top park street suffered awkward slope desirability link building museum art gallery situated adjacent plot architecture critic roger gill stated building remarkable size noted ambience medieval university strangely lacking goes criticise building sham folly armorials founder window represent interests present founding university bristol including wills fry families tyndalls park estate royal fort house also purchased trustees tyndall family allowing university expand many departments faculty arts housed large victorian houses converted teaching goldney gardens entered property university bristol george wills hoped build all-male hall residence prevented due moral objection warden clifton hall house objected idea male female residences close proximity university records show miss starvey prepared resign issue support chancellor conwy lloyd morgan eventually land purchased stoke bishop allowing wills hall bought allowing building described quasi-oxbridge hall added dame monica wills chapel george wills widow death burwalls mansion house side avon gorge used halls residence past home sir george oatley building used house centre continuing education many modern buildings including senate house newer parts hh wills physics laboratory designed ralph brentnall funds university grants committee also responsible extension wills memorial building library completed standard realise extension original building brentnall oversaw rebuilding great hall wills memorial building partly destroyed bristol blitz world war ii buildings st michael hill rebuilt using hundreds old photographs recreate original houses flats goldney hall designed michael grice received award civic trust design bristol university owns best examples georgian architecture city best examples royal fort house clifton hill house goldney hall despite additions victoria rooms house music department designed charles dyer seen good example greek revival movement british architecture tympanum building depicts scene advent morning designed jabez tyley major feature large organ since destroyed fire november 2016 university announced plans build £300 million temple quarter campus c. 5,000 students next bristol temple meads railway station within bristol temple quarter enterprise zone new campus include business school digital research facilities student village expected open 2021 existing campus plans remodel tyndall avenue pedestrianise surrounding area build new library resource hub common uk universities bristol headed formally chancellor currently sir paul nurse led day-to-day basis vice-chancellor currently hugh brady academic leader chief executive four pro vice-chancellors three ceremonial pro-chancellors chancellor may hold office ten years pro-chancellors three unless university court determines otherwise vice-chancellor pro-vice-chancellors term limits vice-chancellor supported deputy vice-chancellor responsibility running university held executive level vice-chancellor council body recommend changes university statutes charter exception academic ordinances made consent senate chief academic body university also holds responsibility teaching learning examinations research enterprise chancellor pro chancellors nominated council appointed formally court whose additional powers limited appointments others including lay members council finally convocation body staff ceremonial officers graduates university returns 100 members court one member council otherwise principally forum discussion ensure graduates stay touch university university made number schools departments organised six faculties university specifies mix cambridge oxford academic dress part uses oxford-style gowns cambridge-style hoods required 'university red see logo top page 2004 university unveiled new crest icons crest sun wills family dolphin colston horse fry ship-and-castle medieval seal city bristol also used coat arms shape whole crest represents open book learning crest replaced university arms shown arms continue used specific historical ceremonial requirement arms comprise argent cross quadrate gules arms city bristol pale sun splendour wills open book proper leaved clasped inscribed words nisi quia dominus fesse sinister dolphin embowed colston dexter horse courant fry third inscription book latin opening 124th psalm lord side ... bristol 8th highest average entry qualification undergraduates uk university 2015 new students averaging 485 ucas points equivalent aaaaa a-level grades competition places high average 7.7 applications per place according 2014 sunday times league tables making joint 11th competitive university uk university gives offers admission 67.3 applicants 8th lowest amongst russell group according 2017 times sunday times good university guide approximately 40 bristol undergraduates come independent schools 2016-17 academic year university domicile breakdown 78:5:17 uk eu non-eu students respectively female male ratio 55:45 bristol ranked 10th overall sunday times 10-year 1998–2007 average ranking british universities based consistent league table performance member 'sutton 13 top ranked universities uk internationally 2016 qs world university rankings placed bristol 41st overall world 2012 2013 rankings also placed bristol 15th world terms reputation employers placing higher several american ivy league universities including princeton university cornell upenn bristol chosen ninth best university uk quality graduates according recruiters uk major companies another international ranking shanghai jiao tong university academic ranking world universities placed bristol 64th globally 2013 times higher education world university ranking placed bristol 66th 2011 bristol ranked 47th world 6th uk 2016 round university ranking 2017 u.s. news world report ranks bristol 76th world 2019 ranked 120th among universities around world scimago institutions rankings according data published sunday times bristol sixth-highest percentage good honours uk university 2010 centre higher education development excellence rankings bristol one four uk universities oxford ucl manchester rated excellent seven departments following courses offered university bristol managed reach top 5 'times ranking 2008 computer science 3rd electrical electronic engineering 3rd civil engineering 5th biological sciences 3rd mathematics 3rd psychology 4th furthermore qs world university rankings place bristol world top 100 universities subject areas 2011 arts humanities 57th natural sciences 40th engineering 83rd social sciences 65th life sciences 70th breakdown qs world university natural sciences ranking shows following earth sciences 25th mathematics 35th environmental sciences 39th physics 41st chemistry 48th addition bristol particularly strong field social sciences particularly economics finance management rated fourth 2008 guardian university guide business management studies 2011 guardian also ranked bristol third uk geography behind second place oxford ranked bristol 1st uk music complete university guide 2013 bristol ranked fifth german fourth russian third mechanical civil engineering third music second drama bristol also known research strength 15 departments gaining top grade 5* 2001 research assessment exercise overall 36 46 departments rated gained top two ratings 5 5* 76 academic staff working departments scored top two levels terms teaching strength bristol average teaching quality assessment score 22.05/24 tqa abolished bristol drop-out rate also lower benchmark set hefce 3.1 bristol awards range academic degrees spanning bachelor master degrees well junior doctorates higher doctorates postnominals awarded degree abbreviations used commonly among british universities university part engineering doctorate scheme awards eng d. systems engineering engineering management aerospace engineering non-destructive evaluation bristol notably award title bachelor degrees music available study awarded ba although award mmus dmus degree divinity since divinity available study students theology awarded ba similarly university award blitt bachelor letters although award mlitt dlitt regulations university name md dds higher doctorates although many universities degrees normally accredited professional doctorates degrees dlitt dsc deng lld dmus whilst regulations specifying grounds award often conferred honorary degrees honoris causa used commonly dlitt dsc lld occasionally mlitt also sometimes conferred honorarily distinction local area within university university bristol students union bristol su bsu located queen road founding member national union students amongst oldest students unions england union oversees three media outlets ubtv bristol university radio station burst student newspaper epigram also local branch tab terms student life union responsible organisation annual freshers fair co-ordination bristol student community action organises volunteering projects local community organisation entertainment events large number student societies previous presidents included sue lawley former liberal democrat mp lembit öpik separate union postgraduate students well athletic union member british universities colleges sport distinction blues awarded sporting excellence oxford cambridge bristol successful athletes awarded reds accommodation students primarily central precinct university two areas bristol clifton stoke bishop known respectively west north villages stoke bishop wills hall edge clifton downs first opened 1929 chancellor winston churchill original quadrangle layout expanded twice 1962 1990 churchill hall named chancellor followed 1956 badock hall 1964 time badock hall establishment buildings called hiatt baker hall two years later hiatt baker moved site largest hall university first self-catering hall stoke bishop university hall established 1971 expansion 1992 university newest undergraduate residence 33 colston street opened city centre october 2011 acquiring property 2009 university established partnership unite plc order provide accommodation due increase number students accepted entry academic year 2012/2013 £20 million project expanding facilities hiatt baker provide additional 327 places undergraduate students 2014 main halls elect groups students junior common room organise halls social calendar next year residents student houses private accommodation students living home become members orbital – society organising social events students throughout year clifton goldney hall built first early 18th century wealthy merchant goldney family eventually became part university 1956 popular location filming chronicles narnia house eliott truly madly deeply well episodes fools horses casualty filmed grotto grounds grade listed building clifton hill house another grade listed building used student accommodation clifton original building constructed 1745 1750 isaac ware used university since earliest days 1909 manor hall comprises five separate buildings principal erected 1927–1932 design george oatley following donation henry herbert wills one annexes manor house recently refurbished officially 'reopened 1999 goldney hall beautiful gardens modern accommodation complexes clifton hill house dated facilities clifton residences also possesses attractive gardens manor hall houses largest dated rooms dating back early 20th century central precinct sits hawthorns student house accommodating 115 undergraduate students house started life collection villas built somewhere 1888 1924 later converted bit bit hotel john dingle hawthorns also houses conferencing facilities staff refectory bar accommodation office student houses office several residences central precinct recent built managed third-party organisations exclusivity arrangements university include new bridewell house opened 2016 includes en-suite bedrooms studios former police hq operated fresh student housing unite house chantry court opened 2000 2003 respectively unite group well dean court 2001 postgraduates woodland court 2005 run dominion housing group current academics university bristol include 18 fellows academy medical sciences 10 fellows british academy 13 fellows royal academy engineering 31 fellows royal society include sir michael berry one discoverers quantum mechanics geometric phase john rarity international expert quantum optics quantum cryptography quantum communication david may computer scientist lead architect transputer mark horton british maritime historical archaeologist academics computer science include david cliff inventor seminal zip trading algorithm peter flach mike fraser professor human-computer interaction julian gough nigel smart past academics university include patricia broadfoot vice-chancellor university gloucestershire nigel thrift vice-chancellor university warwick wendy larner provost victoria university wellington anthony epstein co-discoverer epstein-barr virus professor pathology university 1968–1982 sir john lennard-jones discoverer lennard-jones potential physics alfred marshall one university college principals influential economist latter part 19th century mathematicians philosophers rohit parikh brian rotman lectured mathematics department philosopher science paul feyerabend taught department philosophy university bristol associated three ig nobel prizes award unusual trivial achievements scientific research sir michael berry shared award andre geim nobel laureate using magnets levitate frog gareth jones also shared ig nobel prize scientifically documenting fellatio fruit bats dr. len fisher awarded 1999 prize physics calculating optimal way dunk biscuit bristol alumnus paul dirac went win nobel prize physics 1933 contribution formulation quantum mechanics considered one significant physicists 20th century notable scientists include dani rabaiotti environmental scientist science communicator notable alumni include writers dick king-smith sarah kane olivier award winning playwright laura wade angela carter dorothy simpson david gibbins david nicholls author novel starter ten turned screenplay set university bristol mark simmons author business books hutton economist author commentator entertainment current affairs former students include journalist mcmafia author misha glenny james landale bbc news chief political correspondent founded university independent newspaper epigram author journalist julie myerson william lewis editor-in-chief telegraph media group derren brown illusionist sue lawley radio 4 presenter alastair stewart newsreader dominic waghorn sky news us correspondent susanna reid itv breakfast anchor studied politics philosophy law university 1989 1992 also editor student newspaper epigram comedy matt lucas david walliams simon pegg chris morris creator controversial brass eye jon richardson comedy stars include chris langham thick fame standup comic marcus brigstocke alumni include mike bennett digital media entrepreneur albert ii prince monaco musician james blunt former liberal democrat mp lembit öpik president bristol university students union time sir jonathan evans former head mi5 anne mcclain member 2013 nasa astronaut class nkosazana dlamini-zuma chairperson african union commission october 2012 january 2017. notable alumni film television production department include film directors mick jackson michael winterbottom marc evans christopher smith alex cox peter webber maddie moate amongst many others
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Computer architecture
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synchronous data flow synchronous dataflow restriction kahn process networks nodes produce consume fixed number data items per firing allows static scheduling
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Computer architecture
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microsoft services microsoft online services refers hosted technology solutions consumers businesses services previously branded windows live umbrella among services offered webmail storage contacts calendar accessed microsoft account microsoft services team provides wide range consulting support services consumers partners businesses web services feature metro user interface ui header contains pull-down element allows users switch outlook.com people calendar skydrive header color also changes depending web service user using exception outlook.com allows users customize header color according preference interface also in-built messaging sidebar allows users interact contacts messenger facebook skype using instant messages audio calls video calls
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Web technology
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insider threat management insider threat management process preventing combating detecting monitoring employees remote vendors contractors fortify organization data theft fraud damage insider individual employed agency access facilities sensitive information organizational data information systems equipment may accounts giving legitimate access computer systems access originally given serve performance duties permissions could abused harm organization insiders often familiar organization data intellectual property well methods place protect makes easier insider circumvent security controls aware physical proximity data means insider need hack organizational network outer perimeter traversing firewalls rather building already often direct access organization internal network insider threats harder defend attacks outsiders since insider already legitimate access organization information assets insiders may comprise permanent temporary employees vendors contractors suppliers ex-employees common insiders elevated access utilize sensitive information without drawing suspicion however anyone insider threat organization dispose secure utilize sensitive information described agency regulations cases individuals compromised opposing agency exploited individual financial status threats life factors order force individual comply opposing agencies demands insider may attempt steal property information personal gain benefit another organization country attacks may range information data stolen destruction business property insiders may perform following threats organization insiders similar characteristics compiled order help determine possible threats researchers identified insiders mainly show antisocial behavior may include limited machiavellianism narcissism psychopathy information system side list common behavioral indicators known insiders insider threat program management educational resources national insider threat special interest group nitsig created response u.s. goverment presidential executive order 13587 structural reforms improve security classified networks responsible sharing safeguarding classified information national insider threat policy national industrial security program operating manual conforming change 2 nitsig created function national insider threat information sharing analysis center nitsig membership largest network 1000+ insider threat mitigation professionals u.s. globally willingness members collaborate share information among membership driving force made nitsig successful encourage become member attend meetings events charge become member https //nationalinsiderthreatsig.org insider threat defense group one first companies offer comprehensive insider threat program development management training u.s. government agencies department defense intelligence community defense contractors required develop implement insider threat programs https //www.insiderthreatdefense.us damaging insider threat incident impacts insider threat incidents severe costly damaging incidents insiders malicious non-malicious insider incidents damaging malicious incidents listed link numerous insider threat incidents severe impacts organizations https //www.insiderthreatdefense.us/insider-threat/
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Computer security
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cloudendure cloudendure cloud computing company develops business continuity software disaster recovery continuous backup live migration cloudendure headquartered united states r israel cloudendure founded 2012 ofer gadish ceo gil shai cro ofir ehrlich vp r leonid feinberg vp product founders previously established acceloweb acquired limelight networks 2011 cloudendure raised total 18.2 million private investors companies dell emc vmware mitsui infosys magma venture partners awards cloudendure include 2017 crn emerging vendors award storage startups 2016 gartner cool vendor award cloudendure products integrated oem software several partner company services including integration google cloud vm migration service integrations cisco systems cloudcenter disaster recovery migration sungard availability services cloud recovery amazon made offer purchase cloudendure january 2019 200 250 million negotiated price outbid google acquired company january 10 2019 cloudendure disaster recovery performs continuous block-level replication saves dormant copy target infrastructure uses smaller percentage compute storage memory primary site leads minimal rtos recovery time objective rpos recovery point objective spun disaster company offers two tiers disaster recovery well continuous backup live migration products cloudendure ’ software service saas application-agnostic replicate workloads physical virtual cloud-based infrastructure variety target sites including amazon web services aws google cloud platform gcp microsoft azure vmware cloudendure ltd. holds pending seven patents including disaster recovery disaster recovery plan drp business continuity recovery time objective rto recovery point objective rpo continuous data protection
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Computer security
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pkzip pkzip file archiving computer program notable introducing popular zip file format pkzip first introduced ms-dos ibm-pc compatible platform 1989 since versions released number architectures operating systems pkzip originally written phil katz marketed company pkware inc bearing initials 'pk 1970s file archiving programs distributed standard utilities operating systems include unix utilities ar shar tar utilities designed gather number separate files single archive file easier copying distribution archives could optionally passed stream compressor utility compress others archivers also appeared 1980s including arc system enhancement associates inc. sea rahul dhesi zoo dean w. cooper dwc lharc haruhiko okomura haruyasu yoshizaki arj stands archived robert jung development pkzip first announced file softdev.doc within pkpak 3.61 package stating would develop new yet unnamed compression program announcement made following lawsuit sea pkware inc although sea suit lost compression war user base migrated pkzip compressor choice led bbs sysops refused accept offer files compressed .arc files users began recompressing old archives currently stored .arc format .zip files first version released 1989 dos command-line tool distributed shareware model us 25 registration fee us 47 manual help ensure interoperability zip format phil katz published original .zip file format specification appnote.txt documentation file pkware continued maintain document periodically published updates originally bundled registered versions pkzip later available pkware site specification version number necessarily correspond pkzip version numbers especially pkzip 6 later various times pkware adds preliminary features allows pkzip products extract archives using advanced features pkzip products create archives wo n't available next major release although popular time zip archives using pkzip 1.0 compression methods rare many modern unzip tools unable handle shrinking reducing although imploding usually supported shrinking uses dynamic lzw unisys held patents patent reduce algorithm also filed june 19 1984 long pkzip produced pkware also used pkzip standards following products
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Computer file systems
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portable distributed objects portable distributed objects pdo application programming interface api creating object-oriented code executed remotely network computers created next computer inc. using openstep system whose use objective-c made package easy write characterized light weight high speed comparison similar systems corba versions pdo available solaris hp-ux versions openstep system version worked microsoft ole also available called d'ole allowing distributed code written using pdo platform presented microsoft systems local ole objects pdo one number distributed object systems created early 1990s design model front end applications gui-based microcomputers would call code running mainframe minicomputers processing data storage microsoft evolving ole component object model com similar distributed version called dcom ibm system object model som/dsom sun microsystems promoting distributed objects everywhere host smaller players well exception limited functionality com systems extremely heavyweight tended large slow often difficult use pdo hand relied small number features objective-c runtime handle portability well distribution key feature language support second chance method classes method call object failed object n't support normally allowed languages due strong typing runtime would bundle message compact format pass back object codice_1 method normal behavior codice_1 return error including details taken message invocation pdo instead supplied number new objects codice_1 methods passed invocation object another machine network various versions support different networks platforms calling methods remote objects almost invisible network setup lines typically pdo objects instantiated locally called way object system pdo object forwarded invocation remote computer processing unbundled results returned comparison corba pdo programs typically 1/10 less size common next staffers write magazines showing re-implement multi-page corba article perhaps 15 lines code programming standpoint nearly nothing easy use pdo however pdo also reliant entirely objective-c function price unwilling pay time c++ widely used effort shift codebases entirely new language paradigm considered onerous pdo never saw much use next emphasis shifted new webobjects framework 1995 pdo continues used mac os x programmers method interprocess interapplication communication communication networked applications need compatibility mac os x applications addition os x platform gnustep implementation distributed objects
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Operating systems
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animaker animaker diy video animation software software cloud-based launched 2014 allows users create animated videos using pre-built characters templates 2017 animaker became first tool launch animated vertical video creator animaker cloud-based video animation software first launched open beta version 2014 february 2015 software officially launched based freemium model allowed users free account option software provides online tools create edit video animation software developed animaker inc video based saas company founded rs raghavan animaker uses html5 adobe flash create animated videos exported facebook youtube downloaded mp4 file software also available chrome extension chrome web store
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Distributed computing architecture
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hstcp highspeed tcp hstcp congestion control algorithm protocol defined rfc 3649 transport control protocol tcp standard tcp performs poorly networks large bandwidth-delay product unable fully utilize available bandwidth hstcp makes minor modifications standard tcp congestion control mechanism overcome limitation ack received congestion avoidance window increased formula_1 loss detected triple duplicate acknowledgments window decreased formula_2 w current window size congestion window small hstcp behaves exactly like standard tcp w 1 b w 0.5 tcp congestion window beyond certain threshold w b w become functions current window size region congestion window increases value w increases value b w decreases means hstcp window grow faster standard tcp also recover losses quickly behavior allows hstcp friendly standard tcp flows normal networks also quickly utilize available bandwidth networks large bandwidth delay products hstcp slow start/timeout behavior standard tcp since congestion control mechanism modified hstcp used tcp options like sack real implementations determining increase decrease parameters given current window size implemented lookup table
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Internet protocols
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.htpasswd .htpasswd flat-file used store usernames password basic authentication apache http server name file given .htaccess configuration anything although .htpasswd canonical name file name starts dot unix-like operating systems consider file begins dot hidden file often maintained shell command htpasswd add delete update users properly encode password use easily checked reversed back original password file consists rows row corresponding username followed colon followed string containing hashed password optionally prepended algorithm specifier 2y apr1 sha and/or salt hash historically used unix crypt style md5 sha1 common alternatives although version 2.2.18 variant md5 default resources available apache http server restricted users listed files created htpasswd .htpasswd file used protect entire directory placed well particular files
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Web technology
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digg reader digg reader news aggregator operated digg reader released june 26 2013 response google reader shutting reader web-based also ios android applications well google chrome extension beta reader received mostly positive reviews march 26 2018 digg shut digg reader digg reader created response google reader shutting andrew mclaughlin ceo digg saw blog post fall 2012 speculating google reader shutting sent note one friends google jokingly offering buy reader mclaughlin sent serious reply said nothing buy february 2013 mclaughlin friend google said referring google reader ’ telling anything ’ going keep thing around forever maybe want something ready end year. ” google announced google reader shutting july 1 2013 digg announced development digg reader night digg officially announced development reader march 13 2013 instead original plan late 2013 moving project top priority list promised simulate best features google reader also updating fit 2013 digg reader initially launched june 21 2013 invite service launched publicly june 26 2013 july 2 2013 digg reader announced crawling 7.7 million feeds march 14 2018 digg announced would shutting digg reader march 26 2018 june 27 2013 digg reader integrated digg ios app form update digg decided make reader separate app company sees digg.com digg reader complementary products cnet gave app 3/5 stating digg beautiful app blends social news rss subscriptions bugs missing features make suitable committed digg users app current version rating 4.5 5 itunes app received app store best 2013 award apple well best 2013 award techcrunch august 29 2013 digg released android app digg reader digg says android app common request users app rating 3.9 5 google play october 9 2013 digg released google chrome extension digg reader extension rating 4 5 chrome web store early reviews beta mostly positive mashable liked saying extremely impressed criticized lack features search tagging pc magazine gave 4/5 praising clean design speed free price tag criticized lack opml support inability log email address required connection google autostraddle gave thumbs citing neat streamlined look free price tag speed disappointed n't share feature facebook twitter techcrunch impressed digg able produce functional google reader alternative said current form digg reader replacement google reader blinklist.com said good way get news want lacked certain appeal compared free apps maclife critical giving 2/5 stating barely accomplishes creators set ’ little doubt digg reader improve time gate disappoints despite clean user interface many basic features lacking especially kind rss solution power users depended upon google reader provide
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Web technology
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kongoni operating system kongoni linux distribution used free version linux kernel distributed linux-libre project development kongoni project currently dormant kongoni desktop oriented operating system strong belief free freedom aimed easy install use customize kongoni ship include offer ability install software approved free software foundation kongoni shona word gnu animal gnu project takes name name chosen represents spirit history kongoni linux operating system african origin release kongoni named great philosophers including aristotle sophocles nietzsche cicero version kongoni compatible slackware release based natively install packages slackware project currently dormant september 2010 project maintained one developer robert gabriel previously project maintained a.j venter kongoni offered live cd option install os hard-drive kongoni os installs software use ports allows one download source code program opposed pre-compiled binary file compiled built automatically users system offers benefit smaller downloads programs may run faster and/or use less memory compiled explicitly users system kongoni shipped several pieces unique code including
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Operating systems
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juanita moody juanita moody née morris may 29 1924 – february 17 2015 american cryptographer intelligence analyst worked signals intelligence service national security agency 1943 1976 juanita morris born 1924 morven north carolina began studying western carolina university 1942 left early 1943 join war effort volunteered recruitment office charlotte north carolina april sent arlington hall headquarters signals intelligence service arlington virginia began training cryptanalysis waiting security clearance later transferred administrative library role remained interested cryptanalysis however joined group met outside work study complex unbroken german code system result assigned official code-related tasks successful breaking german one-time pad cipher end war promoted code clerk head office planned return western carolina university end war supervisor asked remain sis agreed condition given complicated job 1948 married fellow civil servant warren moody moody promoted national security agency research development department war became involved computational cryptanalysis analytic machines 1950s supervisor soviet analytic affairs early 1960s head signals intelligence operations gather information cuba operation mongoose chief office non-communist nations oversaw nsa responses cuban missile crisis october 1962 responsible deciding information relating crisis would collected processed released promoted higher positions nsa throughout 1960s early 1970s became focus controversy 1975 called testify front senate committee investigating abuses power federal intelligence agencies name widely associated investigation press nsa later clarified involved abuses power involvement investigation spokesperson 1975 moody awarded inaugural national intelligence medal achievement retired nsa following year 33 years working agency inducted nsa hall honor 2003
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Computer security
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hive ui hive stylized hive custom rom developed xolo built android operating system v 4.4.4 kitkat hive exclusive xolo devices licensed third-parties hive designed xolo software design team bangalore users interact development team share ideas new features hive development team aims release over-the-air updates new features bug fixes every fortnight first xolo device 8x-1000 hive launched august 2014
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Operating systems
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power-on self-test power-on self-test post process performed firmware software routines immediately computer digital electronic device powered article mainly deals posts personal computers many embedded systems major appliances avionics communications medical equipment also self-test routines automatically invoked power-on results post may displayed panel part device output external device stored future retrieval diagnostic tool since self-test might detect system usual human-readable display non-functional indicator lamp speaker may provided show error codes sequence flashes beeps addition running tests post process may also set initial state device firmware case computer post routines part device pre-boot sequence complete successfully bootstrap loader code invoked load operating system ibm pc compatible computers main duties post handled bios may hand duties programs designed initialize specific peripheral devices notably video scsi initialization duty-specific programs generally known collectively option roms individually video bios scsi bios etc principal duties main bios post follows functions served post bios versions back first later bios versions post also bios begins post cpu reset first memory location cpu tries execute known reset vector case hard reboot northbridge direct code fetch request bios located system flash memory warm boot bios located proper place ram northbridge direct reset vector call ram earlier pc systems chipsets standard bios rom would located address range included reset vector bios ran directly rom motherboard bios rom segment f000 conventional memory map post flow contemporary bios one first things bios determine reason executing cold boot example may need execute functionality however system supports power saving quick boot methods bios may able circumvent standard post device discovery simply program devices preloaded system device table post flow pc developed simple straightforward process one complex convoluted post bios must integrate plethora competing evolving even mutually exclusive standards initiatives matrix hardware oses pc expected support although simple memory tests setup screen displayed earlier bioses around turn millennium post would perform thorough test devices including complete memory test design ibm modeled larger e.g mainframe systems would perform complete hardware test part cold-start process pc platform evolved commodity consumer device mainframe- minicomputer-inspired high-reliability features parity memory thorough memory test every post dropped models exponential growth pc memory sizes driven equally exponential drop memory prices also factor duration memory test using given cpu directly proportional memory size original ibm pc could equipped little 16 kb ram typically 64 640 kb depending amount equipped memory computer 4.77 mhz 8088 required five seconds 1.5 minutes complete post way skip beginning ibm xt memory count displayed post instead blank screen modern pc bus rate around 1 ghz 32-bit bus might 2000x even 5000x faster might 3 gb memory—5000x people concerned boot times 1980s 30 60 second memory test adds undesirable delay benefit confidence perceived worth cost users clone pc bioses allowed user skip post ram check pressing key modern machines often performed ram test unless enabled via bios setup addition modern dram significantly reliable dram 1980s part starting sequence post routines may display prompt user key press access built-in setup functions bios allows user set various options particular mother board operating system loaded key pressed post proceed boot sequence required load installed operating system original ibm bios made post diagnostic information available outputting number i/o port 80 screen display possible failure modes progress indication error codes generated case failure generate code code last successful operation available aid diagnosing problem using logic analyzer dedicated post cardan interface card shows port 80 output small displaya technician could determine origin problem operating system running computer code displayed board may become meaningless since oses e.g linux use port 80 i/o timing operations actual numeric codes possible stages error conditions differ one bios supplier another codes different bios versions single supplier may also vary although many codes remain unchanged different versions later bioses used sequence beeps motherboard-attached pc speaker present working signal error codes vendors developed proprietary variants enhancements msi d-bracket post beep codes vary manufacturer manufacturer information numeric beep codes available manufacturers bioses motherboards websites collect codes many bioses reference amibios8 check point beep code list version 2.0 last updated 10 june 2008 post beep codes covered specifically comptia a+ exam apple macintosh computers also perform post cold boot event fatal error mac make startup chime macs made 1987 prior 1998 upon failing post immediately halt death chime sound varies model beep car crash sound sound shattering glass short musical tone screen working sad mac icon along two hexadecimal strings used identify problem macs made prior 1987 crashed silently hexadecimal string sad mac icon apple introduced imac 1998 radical departure macs time imac began production new world macs called new world macs imac power macintosh g3 blue white power mac g4 pci graphics powerbook g3 bronze keyboard powerbook g3 firewire load mac os rom hard drive event error fatal hardware error display screen seen holding startup error message instead 0 prompt event fatal hardware error give beeps beep codes revised october 1999 since addition models power led would flash cadence amiga historical line computers a1000 4000 present interesting post sequence prompts user sequence flashing screens different colors rather audible beeps systems show various hardware post tests correct else failed amiga system performs following steps boot system fails rom test screen display turns red system halts almost amiga models present color sequence turned black screen dark gray light gray color screens filling monitor screen rapid sequence amigas taken usually 2 least max 3 seconds turn boot a4000 presents light gray screen boot time occurs 2 max 3 seconds keyboards historical amiga models proprietary happened early computer ages pragmatically based international standard ansi/iso 8859-1 keyboard intelligent device processor 4 kilobytes ram keeping buffer sequence keys pressed thus communicate user fault found flashing main led sequence
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Operating systems
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vlastimil klíma rndr vlastimil klíma born 19 february 1957 benešov czech republic leading cryptographer computer security expert white hat hacker academic taught applied cryptography faculty mathematics physics charles university prague author several works field cryptographic hash functions digital signatures klíma received doctorate faculty mathematics physics charles university 1984 dr. klíma former head research development group federal ministry defense czech republic czech national security authority klíma authored world ’ first on-the-fly encryption system windows 95 98/nt/2000 ethical hacker successfully broke ssl protocol currently works digital security sector
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Computer security
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eternalblue eternalblue cyberattack exploit developed u.s. national security agency nsa according testimony former nsa employees leaked shadow brokers hacker group april 14 2017 one month microsoft released patches vulnerability may 12 2017 worldwide wannacry ransomware used exploit attack unpatched computers june 27 2017 exploit used help carry 2017 notpetya cyberattack unpatched computers exploit also reported used since march 2016 chinese hacking group buckeye apt3 likely found re-purposed tool well reported used part retefe banking trojan since least september 5 2017 eternalblue exploits vulnerability microsoft implementation server message block smb protocol vulnerability denoted entry common vulnerabilities exposures cve catalog vulnerability exists smb version 1 smbv1 server various versions microsoft windows mishandles specially crafted packets remote attackers allowing execute arbitrary code target computer nsa alert microsoft vulnerabilities held five years breach forced hand agency warned microsoft learning eternalblue ’ possible theft allowing company prepare software patch issued march 2017 delaying regular release security patches february 2017 tuesday march 14 2017 microsoft issued security bulletin ms17-010 detailed flaw announced patches released windows versions currently supported time windows vista windows 7 windows 8.1 windows 10 windows server 2008 windows server 2012 windows server 2016 many windows users installed patches two months later may 12 2017 wannacry ransomware attack used eternalblue vulnerability spread next day microsoft released emergency security patches unsupported windows xp windows 8 windows server 2003 february 2018 eternalblue ported windows operating systems since windows 2000 risksense security researcher sean dillon eternalchampion eternalromance two exploits originally developed nsa leaked shadow brokers also ported event made available open sourced metasploit modules end 2018 millions systems still vulnerable eternalblue led millions dollars damages due primarily ransomware worms following massive impact wannacry notpetya badrabbit caused 1 billion worth damages 65 countries using eternalblue either initial compromise vector method lateral movement may 2019 baltimore struggled cyberattack digital extortionists using eternalblue attack froze thousands computers shut email disrupted real estate sales water bills health alerts many services since 2012 four baltimore city chief information officers fired resigned two left investigation eternalblue tool relies flaw microsoft software though company issued patch leakers posted tools online many systems remain vulnerable two years later existence patch prompted security researchers argue saturday responsibility baltimore breach lies city security consultant rob graham wrote tweet “ organization substantial numbers windows machines gone 2 years without patches ’ squarely fault organization eternalblue ” according microsoft united states nsa responsible dint controversial strategy stockpiling vulnerabilities least preventing microsoft timely public patching presumably hidden bugs eternalrocks microbotmassivenet computer worm infects microsoft windows uses seven exploits developed nsa comparatively wannacry ransomware program infected 230,000 computers may 2017 uses two nsa exploits making researchers believe eternalrocks significantly dangerous worm discovered via honeypot eternalblue among several exploits used conjunction doublepulsar backdoor implant tool eternalrocks first installs tor private network conceals internet activity access hidden servers brief 24 hour incubation period server responds malware request downloading self-replicating host machine malware even names wannacry avoid detection security researchers unlike wannacry eternalrocks possess kill switch ransomware
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Computer security
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java embedding plugin java embedding plugin jep enables java mac os x non safari browsers plugin shipped firefox 1.5 recent versions seamonkey camino latest released version 0.9.7.5 requires mac os x 10.4.11 higher originally powerpc based macs port intel x86 needed version 0.9.6.1 security vulnerability allowed remote attackers crash browser
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Internet protocols
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informatica informatica software development company founded 1993 headquartered redwood city california core products include enterprise cloud data management data integration co-founded gaurav dhillon diaz nesamoney anil chakravarthy company ceo april 29 1999 initial public offering nasdaq stock exchange listed shares stock symbol infa april 7 2015 permira canada pension plan investment board announced company controlled permira funds cppib would acquire informatica approximately us 5.3 billion august 6 2015 acquisition completed microsoft salesforce ventures additional investors company stock ceased trading nasdaq ticker symbol infa effective date informatica product portfolio focused data integration extract transform load information lifecycle management business-to-business data exchange cloud computing integration complex event processing data masking data quality data replication data virtualization master data management ultra messaging components form toolset establishing maintaining data warehouses customer base 5,000 companies 2006 informatica announced cloud business informatica grown combination sales growth company acquisitiond
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Distributed computing architecture
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rainbowcrack rainbowcrack computer program generates rainbow tables used password cracking rainbowcrack differs conventional brute force crackers uses large pre-computed tables called rainbow tables reduce length time needed crack password drastically rainbowcrack developed zhu shuanglei implements improved time–memory tradeoff cryptanalysis attack originated philippe oechslin ophcrack organizations made rainbowcrack rainbow tables available free internet
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Computer security
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navitaire inc v easyjet airline co. bulletproof technologies inc. navitaire inc v easyjet airline co. bulletproof technologies inc. decision england wales high court justice chancery division case involved copyright infringement claim brought navitaire inc. navitaire easyjet airline company easyjet bulletproof technologies inc. bulletproof regards software used construct airline booking ticket reservation system curiously claimed defendant access original source code defendant source code resembled plaintiff way case affirms source code object code program i.e underlying framework may protected copyright programming language used create program well program functional aspects interfaces protected computer programs unique one achieve similar end result different means however artistic aspects may protected copyright subsists visual images created icons graphical user interfaces guis directive legal protection computer programs apply images specific case held writing original source code results similar identical function another program result infringement program navitaire also confirmed notion injunction would granted n't oppressive navitaire court approach confirmed opinions court appeals 2007 decision nova productions limited vs. mazooma games limited court held program infringe another produces similar results different underlying source code henry carr qc mark vanhegan anna edwards-stuart instructed field fisher waterhouse claimants richard arnold qc brian nicholson instructed herbert smith defendants claimant navitaire inc. navitaire developed system called openres ticketless airline booking application used number airlines users receive ticket given single reference number check-in airport navitaire owns copyright various works make source code openres software openres predominantly coded cobol navitaire predecessors open skies inc. open skies division hewlett packard open skies coded developed web interface openres called takeflight court refers navitaire open skies inc. collectively navitaire takeflight module consists source code navitaire developed airline booking system called openres predecessor open skies licensed software easyjet easyjet access underlying code navitaire suggest easyjet bulletproof access openres however studying functionality openres easyjet bulletproof developed system called eres also web interface substantially indistinguishable openres easyjet dispute allegation wanted new system substantially indistinguishable openres interface also disputed underlying code eres resemble openres codes easyjet created program studying observing navitaire system worked although code different eres acts upon identical similar inputs produces similar results openres thus navitaire filed action copyright law based alleging copyright infringement based non-textual copying specifically navitaire claimed similarity business logic overall look feel software functionality software rose level non-textual copying also regards takeflight known easyjet copied modified several occasions fix bugs provide display promotions etc provide foreign language interfaces code internationalized navitaire alleges easyjet breached license alleging non-textual copying software easyjet produced user interface look feel takeflight general matter court stated emulate action piece software writing software internal similarity first deliberately designed 'look achieve results far uncommon navitaire right far-reaching submission much work may amount infringement copyright original computer program even alleged infringer access source code investigate decompile executable program non-textual copying raised access issue three aspects non-contextual copying openres system consists database well series programs manipulate data interface consists single complex commands entered user relevant display screens different interfaces regards databases navitaire claimed copyright infringement occurred two points 1 transferring 'migrating data contained openres databases new easyres system easyjet made interim copies existing openres databases granted permission 2 easyjet bulletproof used knowledge openres databases design eres databases infringed copyright structure program court find infringement since databases manipulated way openres navitaire alleged eres violated copyright replicated overall look feel software i.e business logic relied required identical similar commands entered operator openres system copying icons displayed gui copying text-based screen displays well results produced software four classes relevant copyright works identified summary issues follows navitaire contend copyright subsists command set copyright work distinct source code claim number aspects collection commands whole entitled copyright 'compilation ii commands copyright work right iii alternatively 'complex commands work right displays navitaire contend respect vt100 screen displays 'template fixed data layout variable data separate copyright work display ii certain gui screens separate schedule maintenance module copyright works stand copied said quite distinct allegation similarity exhibited eres openres eye user 'non-textual copying whole source code said strictly analogous taking plot book 12 author takes plot another work copies nothing else still infringe copyright substantial part earlier author work represented plot goes computer programs john richardson computers v flanders 1993 fsr 497 ferris j easyjet accepts copyright subsists source code openres however stressed court regards user interface question considered whether substantial part taken since none code directly copied eres used command names substantial part source code agree copyright subsists command set either individual commands compilation since works begin moreover graphical displays also works contended non-contextual copying would extend protection copyright matters legitimately covered copyright argued claim went functional idea program rather expression idea software 1 comes computer programs copyright law protect non-textual copying long underlying source code different problem ultimate look feel similar present case fact easyjet n't access aided court finding infringement moreover court took account peculiar aspect computer programs several different ways producing similar identical result business logic i.e functionality program protected copyright law finding otherwise would extend copyright unjustifiably based navitaire merely copying look feel program website rise level infringement copyright using underlying ideas principles without copying actual expression source code infringe another even functionality however appearance may argued infringing artistic work see details metaphor navitaire urged easyjet studying openres system functionality resulted taking substantial part source code similar reading novel taking plot using plot new novel however court disagreed reasoning found computer programs code like novel instead court found case like chef invents pudding using different recipe original derives similar result one chef several tries comes tasty pudding dish writes recipe another chef tries decides recreate comes recipe would considered infringement although results means derive different 2 single words complex commands compilation commands qualify literary works single word commands qualify literary works necessary qualities literary work based 1988 act test considered merely whether written artefact accorded status copyright work regard kind skill labour expended nature copyright protection underlying policy complex commands i.e commands syntax one arguments must expressed particular way also qualify 1988 act mandates literary work written recorded moreover recitals 13-15 software directive reinforce computer languages may copyrighted present case identifiable literary work embodied command codes similarly collections commands count language protected compilation protection computer program may extended functionality alone copyright protection computer software given feel courts astute extend protection region functional effects program issue respectable case saying copyright general concerned functional effects advantage bright line rule protecting claimant embodiment function software superset software case truly analogous plot novel plot part work user interface part work one could permute letters codes command names would still work way would lost modest mnemonic advantage approach problem way may least consistent distinction idea expression finds way software directive course draws line idea expression particular place would say lies far side expression think however independence particular form actual codes used overall functioning software legitimate separate way afford separate protection underlying software even arguably copied 3 yes artistic work rise level copyright protection present case vt100 screen displays rise level considered tables found literary character based article 1 2 directive simply ideas underlying computer program interfaces providing merely static framework display dynamic data task software produce however graphic user interfaces guis icons qualified artistic works given protection due skill labour required arrange screens certain way icons copyrighted works court found since icons used guis copyrighted works easyjet made identical copies easyjet infringed navitaire copyright easyjet managed convince court licensees permitted alter modify program resolve bugs make modifications hired however court found infringement database fields reproduced unnecessarily us uk copyright grants protection expression idea idea database right according european union property right eu defined directive 96/9/ec directive legal protection databases passed 11 march 1996 affords legal protection databases granting specific separate legal rights limitations computer records rights collectively known database rights see full text court analyzed section making clear important dichotomy copyright law ideas protected expression thus code written protected interfaces function programming language see full text 3.— 1 part— literary work means work dramatic musical work written spoken sung accordingly includes— table compilation database b computer program c preparatory design material computer program database 2 copyright subsist literary dramatic musical work unless recorded writing otherwise references part time work made time recorded 50ba.— 1 infringement copyright lawful user computer program observe study test functioning program order determine ideas principles underlie element program performing acts loading displaying running transmitting storing program entitled 2 act permitted section irrelevant whether exists term condition agreement purports prohibit restrict act terms virtue section 296a void intellectual property
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Databases
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hierarchical recursive queries sql hierarchical query type sql query handles hierarchical model data special cases general recursive fixpoint queries compute transitive closures standard hierarchical queries implemented way recursive common table expressions ctes unlike oracle earlier connect-by clause recursive ctes designed fixpoint semantics beginning recursive ctes standard relatively close existing implementation ibm db2 version 2 recursive ctes also supported microsoft sql server since sql server 2008 r2 firebird 2.1 postgresql 8.4+ sqlite 3.8.3+ ibm informix version 11.50+ cubrid mariadb 10.2+ mysql 8.0.1+ tableau documentation describing ctes used tibco spotfire support ctes oracle 11g release 2 implementation lacks fixpoint semantics without common table expressions connected-by clauses possible achieve hierarchical queries user-defined recursive functions common table expression cte sql temporary named result set derived simple query defined within execution scope codice_1 codice_2 codice_3 codice_4 statement ctes thought alternatives derived tables subquery views inline user-defined functions common table expressions supported teradata db2 firebird microsoft sql server oracle recursion since 11g release 2 postgresql since 8.4 mariadb since 10.2 mysql since 8.0 sqlite since 3.8.3 hypersql h2 experimental oracle calls ctes subquery factoring syntax recursive cte follows codice_5 ‘ syntax recursive ctes recursive subquery factoring oracle jargon used traverse relations graphs trees although syntax much involved automatic pseudo-columns created like codice_6 desired created code see msdn documentation ibm documentation tutorial examples codice_7 keyword usually needed systems postgresql sql:1999 recursive cte query may appear anywhere query allowed possible example name result using codice_8 codice_7 codice_10 using cte inside codice_11 one populate table data generated recursive query random data generation possible using technique without using procedural statements databases like postgresql support shorter create recursive view format internally translated recursive coding example recursive query computing factorial numbers 0 9 following alternative syntax non-standard codice_12 construct introduced oracle 1980s prior oracle 10g construct useful traversing acyclic graphs returned error detecting cycles version 10g oracle introduced nocycle feature keyword making traversal work presence cycles well codice_12 supported enterprisedb oracle database cubrid ibm informix db2 although enabled compatibility mode syntax follows output query would look like following example returns last name employee department 10 manager employee hierarchy number levels manager employee path two academic textbooks note cover sql:1999 standard datalog oracle extension
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Databases
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cloudlinux os cloudlinux os linux distribution marketed shared hosting providers developed software company cloudlinux inc. cloudlinux os based centos operating system uses openvz kernel rpm package manager first version cloudlinux os released january 2010 operation system introduced compatibility red hat enterprise linux version 6 february 2011 version 7 april 2015 cloudlinux os provides modified kernel based openvz kernel adding set original fully functional solutions main feature lightweight virtual environment lve – separate environment cpu memory io iops number processes limits switching cloudlinux os performed provided cldeploy script installs kernel switches yum repositories installs basic packages allow lve work installation server requires rebooting load newly installed kernel cloudlinux os ’ modify existing packages possible boot previous kernel regular way
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Operating systems
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intel dynamic acceleration intel dynamic acceleration ida sometimes called dynamic acceleration technology dat technology created intel corp. certain multi-core intel microprocessors increases clock rate single core every two cores base operating frequency cores idle designed single threaded programs run faster multi-core intel microprocessors intel later released version ida called enhanced dynamic acceleration technology edat quad core processors boosts performance 2 cores 2 cores utilized intel dynamic acceleration first released core 2 duo mobile processor line new microprocessor lines released intel changed technology naming scheme slightly introduction quad core processors intel modified ida released dual dynamic acceleration dda later released nehalem microarchitecture intel microprocessors made additional changes original ida released improved version called intel turbo boost
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Computer architecture
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joint enterprise defense infrastructure joint enterprise defense infrastructure jedi large united states department defense cloud computing contract reported worth 10 billion dollars companies interested contract included amazon google microsoft oracle rean cloud llc protests google employees google decided drop contention contract conflict corporate values deal considered gift-wrapped amazon oracle co-chaired safra catz contested awarding contract amazon web services led jeff bezos citing national defense authorization act idiq contracts conflicts interest deap ubhi worked amazon time department defense led eric g. bruggink senior judge united states court federal claims place contract award hold august 2019 weeks winner expected announced president donald trump ordered contract placed hold defense secretary mark esper investigate complaints favoritism towards amazon
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Distributed computing architecture
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mobile malware mobile malware malicious software targets mobile phones wireless-enabled personal digital assistants pda causing collapse system loss leakage confidential information wireless phones pda networks become common grown complexity become increasingly difficult ensure safety security electronic attacks form viruses malware cell phone malware initially demonstrated brazilian software engineer marcos velasco created virus could used anyone order educate public threat first known mobile virus timofonica originated spain identified antivirus labs russia finland june 2000 timofonica sent sms messages gsm-capable mobile phones read spanish information telefónica fooling messages sent internet sms gateway movistar mobile operator june 2004 discovered company called ojam engineered anti-piracy trojan hack older versions mobile phone game mosquito sent sms texts company without user knowledge july 2004 computer hobbyists released proof-of-concept virus cabir infects mobile phones running symbian operating system spreading via bluetooth wireless march 2005 reported computer worm called commwarrior-a infecting symbian series 60 mobile phones specific worm replicated phone multimedia messaging service mms sending copies contacts listed phone user address book august 2010 kaspersky lab reported trojan trojan-sms.androidos.fakeplayer.a first sms malware affected google android operating system sent sms messages premium rate numbers without owner knowledge accumulating huge bills currently various antivirus software companies meanwhile operating system developers try curb spread infections quality control checks software content offered digital application distribution platforms google play apple app store recent studies however show mobile antivirus programs ineffective due rapid evolution mobile malware four types common malicious programs known affect mobile devices
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Computer security
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pov-ray persistence vision ray tracer pov-ray ray tracing program generates images text-based scene description available variety computer platforms originally based dkbtrace written david kirk buck aaron a. collins amiga computers also influences earlier polyray raytracer contributed author alexander enzmann pov-ray free open-source software source code available agplv3 sometime 1980s david kirk buck downloaded source code unix ray tracer amiga experimented eventually deciding write ray tracer named dkbtrace initials posted call ray bulletin board system chicago thinking others might interested 1987 aaron a. collins downloaded dkbtrace began working x86-based port david buck collaborated add several features program proved popular anticipated could keep demand features thus july 1991 david turned project team programmers working graphdev forum compuserve time felt inappropriate use initials program longer maintained name star-light software taskforce animation rendering initially used eventually name became pv-ray ultimately pov-ray persistence vision ray tracer inspired dali persistence memory 2002 pov-ray became first ray tracer render image orbit rendered mark shuttleworth inside international space station features application summary history discussed interview february 2008 david kirk buck chris cason episode 24 floss weekly pov-ray matured substantially since created recent versions software include following features one pov-ray main attractions large collection third party support large number tools textures models scenes tutorials found web also useful reference wanting learn ray tracing related geometry graphics algorithms work current official version pov-ray 3.7 version introduces main features previous release 3.6 july 2006 intel corporation started using beta version demonstrate new dual-core conroe processor due efficiency 3.7 beta smp implementation pov-ray addition standard geometric shapes like tori spheres heightfields supports mathematically defined primitives isosurface finite approximation arbitrary function polynomial primitive infinite object defined 15th order lower polynomial julia fractal 3-dimensional slice 4-dimensional fractal superquadratic ellipsoid intermediate sphere cube parametric primitive using equations represent surface rather interior pov-ray internally represents objects using mathematical definitions pov-ray primitive objects described mathematical functions different many 3d computer modeling packages typically use triangle meshes compose objects fact provides pov-ray several advantages disadvantages rendering modeling systems pov-ray primitives accurate polygonal counterparts objects described terms spheres planar surfaces cylinders tori like perfectly smooth mathematically accurate pov-ray renderings whereas polygonal artifacts may visible mesh-based modeling software pov-ray primitives also simpler define polygonal counterparts pov-ray sphere described simply center radius mesh-based environment sphere must described multitude small polygons hand primitive- script-based modeling always practical method create objects realistic characters complex man-made artifacts like cars objects created mesh-based modeling applications wings 3d blender converted pov-ray mesh format following example scene description language used pov-ray describe scene render demonstrates use background colour camera lights simple box shape surface normal finish transforming effects rotation following script fragment shows use variable declaration assignment comparison loop construct pov-ray program include modeling feature essentially pure renderer sophisticated model description language accompany feature set third parties developed large variety modeling software specialized pov-ray others supporting import export data structures including free open-source 3d creation suite blender number additional pov-ray compatible modelers linked povray.org modelling programs 2007 pov-ray acquired rights moray interactive 3-d modeling program long used pov-ray however december 2016 moray development stalled official modifications pov-ray source tree done and/or approved pov-team patch submission and/or bug reporting done pov-ray newsgroups news.povray.org news server web interface also available since pov-ray source available unofficial forks patched versions pov-ray available third parties however officially supported pov-team official pov-ray versions currently support shader plug-ins features like radiosity splines still development may subject syntactical change pov-ray 3.6 distributed compiled format macintosh windows linux support intel macs available macintosh version since mac os x version unix linux version compiled 3.7 versions smp support officially supported windows linux unofficial macintosh versions v3.7 found pov-ray ported platform compatible c++ compiler originally pov-ray distributed pov-ray license namely pov-ray 3.6 distribution license pov-ray 3.6 source license permitted free distribution program source code binaries restricts commercial distribution creation derivative works fully functional versions pov-ray although source code older versions available modification due 3.6 prior license restrictions open source free software according osi fsf definition term problem source code exchange greater foss ecosystem impossible due license incompatibility copyleft licenses one reasons pov-ray originally licensed free software gnu general public license gpl open source licenses pov-ray developed gpl-style licenses became widely used developers wrote license release pov-ray contributors software worked assumption contributions would licensed pov-ray 3.6 licenses 2013 version 3.7 pov-ray relicensed affero general public license version 3 later thus pov-ray since free software according fsf definition also open source software according open source definition
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Programming language topics
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operators c c++ list operators c c++ programming languages operators listed exist c++ fourth column included c states whether operator also present c. note c support operator overloading overloaded operators codice_1 codice_2 codice_3 comma operator sequence point evaluation first operand c++ also contains type conversion operators codice_4 codice_5 codice_6 codice_7 formatting operators means precedence level unimportant operators available c c++ also available languages c java perl php precedence associativity semantics purposes tables codice_8 codice_9 codice_10 represent valid values literals values variables return value object names lvalues appropriate codice_11 codice_12 codice_13 stand type codice_14 class type enumerated type notes following table lists precedence associativity operators c c++ languages operators also exist java perl php many recent languages precedence given operators listed top bottom descending precedence descending precedence refers priority grouping operators operands considering expression operator listed row grouped prior operator listed row operators cell may several rows operators listed cell grouped precedence given direction operator precedence unaffected overloading syntax expressions c c++ specified phrase structure grammar table given inferred grammar iso c 1999 standard section 6.5.6 note 71 states c grammar provided specification defines precedence c operators also states operator precedence resulting grammar closely follows specification section ordering c syntax i.e. grammar specifies precedence operators evaluation expression order major subclauses subclause highest precedence first precedence table mostly adequate resolve details particular note ternary operator allows arbitrary expression middle operand despite listed higher precedence assignment comma operators thus codice_15 interpreted codice_16 meaningless codice_17 expression middle conditional operator codice_18 codice_19 parsed parenthesized also note immediate unparenthesized result c cast expression operand codice_20 therefore codice_21 interpreted codice_22 codice_23 precedence table determines order binding chained expressions expressly specified parentheses many operators containing multi-character sequences given names built operator name character example codice_35 codice_36 often called plus equal minus equal instead verbose assignment addition assignment subtraction binding operators c c++ specified corresponding standards factored language grammar rather precedence table creates subtle conflicts example c syntax conditional expression c++ hence expression parsed differently two languages c expression syntax error syntax assignment expression c c++ parsed valid expression precedence bitwise logical operators criticized conceptually arithmetic operators like expression syntactically parsed whereas expression parsed requires parentheses used often otherwise would historically syntactic distinction bitwise logical operators bcpl b early c operators n't exist instead different meaning depending whether used ‘ truth-value context ’ i.e boolean value expected example behaved logical operator behaved bitwise one retained keep backward compatibility existing installations moreover c++ later versions c equality operations exception three-way comparison operator yield bool type values conceptually single bit 1 0 properly belong bitwise operations c++ defines certain keywords act aliases number operators used exactly way punctuation symbols replace operator different name rather simple token replacements name character string respective operator means expressions identical meanings also means example codice_37 keyword may used replace bitwise-and operator also address-of operator even used specify reference types e.g. iso c specification makes allowance keywords preprocessor macros header file compatibility c c++ provides header inclusion effect
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Programming language topics
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dhcpv6 dynamic host configuration protocol version 6 dhcpv6 network protocol configuring internet protocol version 6 ipv6 hosts ip addresses ip prefixes configuration data required operate ipv6 network ipv6 equivalent dynamic host configuration protocol ipv4 ipv6 hosts may automatically generate ip addresses internally using stateless address autoconfiguration slaac may assigned configuration data dhcpv6 ipv6 hosts use stateless autoconfiguration may require information ip address route dhcpv6 used acquire information even though used configure ip addresses dhcpv6 necessary configuring hosts addresses domain name system dns servers configured using neighbor discovery protocol also mechanism stateless autoconfiguration many ipv6 routers routers residential networks must configured automatically operator intervention routers require ipv6 address use communicating upstream routers also ipv6 prefix use configuring devices downstream side router dhcpv6 prefix delegation provides mechanism configuring routers dhcpv6 uses udp port number 546 clients port number 547 servers dhcp unique identifier duid used client get ip address dhcpv6 server 2-byte duid type field variable-length identifier field 128 bytes actual length depends type server compares duid database delivers configuration data address lease times dns servers etc client first 16 bits duid contain duid type four types meaning remaining duid depends type four types identified rfc 8415 due fact difficult manage multiple identifiers dual-stack environment fact duid simply optimal situations rfc 6939 released giving way identify host based mac address defines way dhcpv6 relay pass information dhcpv6 server option dhcpv6 relays yet widely supported cisco brocade switches support option example without rapid-commit present server link-local address codice_1 client link-local address codice_2 lorenzo colitti google explained dhcpv6 implemented android
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Internet protocols
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data type computer science computer programming data type simply type attribute data tells compiler interpreter programmer intends use data programming languages support common data types real integer boolean data type constrains values expression variable function might take data type defines operations done data meaning data way values type stored type value expression may take value data types used within type systems offer various ways defining implementing using different type systems ensure varying degrees type safety almost programming languages explicitly include notion data type though different languages may use different terminology common data types include example java programming language type int represents set 32-bit integers ranging value −2,147,483,648 2,147,483,647 well operations performed integers addition subtraction multiplication colors hand represented three bytes denoting amounts red green blue one string representing color name allowable operations include addition subtraction multiplication programming languages also allow programmer define additional data types usually combining multiple elements types defining valid operations new data type example programmer might create new data type named complex number would include real imaginary parts data type also represents constraint placed upon interpretation data type system describing representation interpretation structure values objects stored computer memory type system uses data type information check correctness computer programs access manipulate data data types statistics comparable types computer programming vice versa shown following table identified five definitions type used—sometimes implicitly—in literature types including behavior align closely object-oriented models whereas structured programming model would tend include code called plain old data structures five types definition terms representation often done imperative languages algol pascal definition terms value space behaviour used higher-level languages simula clu primitive data types typically types built-in basic language implementation data computers based digital electronics represented bits alternatives 0 1 lowest level smallest addressable unit data usually group bits called byte usually octet 8 bits unit processed machine code instructions called word typically 32 64 bits instructions interpret word binary number 32-bit word represent unsigned integer values 0 formula_1 signed integer values formula_2 formula_3 two complement machine language machine n't need distinguish unsigned signed data types part floating point numbers used floating point arithmetic use different interpretation bits word see https //en.wikipedia.org/wiki/floating-point_arithmetic details machine data types need exposed made available systems low-level programming languages allowing fine-grained control hardware c programming language instance supplies integer types various widths codice_1 codice_2 corresponding native type exist target platform compiler break code using types exist instance 32-bit integer requested 16 bit platform compiler tacitly treat array two 16 bit integers higher level programming machine data types often hidden abstracted implementation detail would render code less portable exposed instance generic codice_3 type might supplied instead integers specific bit-width boolean type represents values true false although two values possible rarely implemented single binary digit efficiency reasons many programming languages explicit boolean type instead interpreting instance 0 false values true boolean data refers logical structure language interpreted machine language case boolean 0 refers logic false true always non zero especially one known boolean 1 composite types derived one primitive type done number ways ways combined called data structures composing primitive type compound type generally results new type e.g array-of-integer different type integer many others possible tend variations compounds example linked list store data array provides sequential access rather random built records dynamic memory though arguably data structure rather type per se also common distinct enough including discussion composite types justified enumerated type distinct values compared assigned necessarily particular concrete representation computer memory compilers interpreters represent arbitrarily example four suits deck playing cards may four enumerators named club diamond heart spade belonging enumerated type named suit variable v declared suit data type one assign four values implementations allow programmers assign integer values enumeration values even treat type-equivalent integers character string types store sequences characters character set ascii since character sets include digits possible numeric string codice_7 however many languages treat belonging different type numeric value codice_8 character string types different subtypes according required character width original 7-bit wide ascii found limited superseded 8 16-bit sets encode wide variety non-latin alphabets hebrew chinese symbols strings may either stretch-to-fit fixed size even programming language may also subtyped maximum size note strings primitive languages instance c composed array characters types based derived basic types explained languages c functions type derived type return value main non-composite derived type pointer data type whose value refers directly points another value stored elsewhere computer memory using address primitive kind reference everyday terms page number book could considered piece data refers another one pointers often stored format similar integer however attempting dereference look pointer whose value never valid memory address would cause program crash ameliorate potential problem pointers considered separate type type data point even underlying representation type specify implementation abstract data type instance stack abstract type implemented array contiguous block memory containing multiple values linked list set non-contiguous memory blocks linked pointers abstract types handled code know care underlying types contained programming agnostic concrete data types called generic programming arrays records also contain underlying types considered concrete specify contents elements laid memory examples include convenience high-level languages may supply ready-made real world data types instance times dates monetary values memory even language allows built primitive types type system associates types computed values examining flow values type system attempts prove type errors occur type system question determines constitutes type error type system generally seeks guarantee operations expecting certain kind value used values operation make sense compiler may use static type value optimize storage needs choice algorithms operations value many c compilers data type example represented 32 bits accord ieee specification single-precision floating point numbers thus use floating-point-specific microprocessor operations values floating-point addition multiplication etc. depth type constraints manner evaluation affect typing language programming language may associate operation varying concrete algorithms type case type polymorphism type theory study type systems although concrete type systems programming languages originate practical issues computer architecture compiler implementation language design type systems may variously static dynamic strong weak typing forth
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Programming language topics
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joe-e joe-e subset java programming language intended support programming according object-capability discipline language notable early object-capability subset language influenced later subset languages adsafe caja/cajita subsets javascript also notable allowing methods verified functionally pure based method signatures restrictions imposed joe-e verifier include cup joe slang coffee serves trademark-avoiding reference java thus name joe-e intended suggest adaptation ideas e programming language create variant java language waterken server written joe-e
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Computer architecture
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tcp westwood tcp westwood tcpw sender-side-only modification tcp new reno intended better handle large bandwidth-delay product paths large pipes potential packet loss due transmission errors leaky pipes dynamic load dynamic pipes tcp westwood relies mining ack stream information help better set congestion control parameters slow start threshold ssthresh congestion window cwin tcp westwood eligible rate estimated used sender update ssthresh cwin upon loss indication agile probing phase proposed modification well-known slow start phase addition scheme called persistent non congestion detection pncd devised detect persistent lack congestion induce agile probing phase expeditiously utilize large dynamic bandwidth resultant performance gains efficiency without undue sacrifice fairness friendliness stability reported numerous papers found tcp westwood home page significant efficiency gains obtained large leaky dynamic pipes maintaining fairness appropriate criterion friendliness i.e opportunistic friendliness tcp westwood shown good controllable friendliness tcp westwood plus evolution tcp westwood fact soon discovered westwood bandwidth estimation algorithm work well presence reverse traffic due ack compression tcp westwood+ version implemented linux kernel
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Internet protocols
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probevue probevue ibm implementation lightweight dynamic tracing environment introduced aix version 6.1 probevue provides ability probe running processes order provide statistical analysis well retrieve data probed process dynamic nature probevue allows used global system performance tool retaining ability drill specific events single process thread modifications required probed process system lightweight design probevue tracing tool suitable use production environment previous tracing tools would performance prohibitive probevue provides series probe point specifications potential events probed script written vue language allows user define probe block code called action block run events occur system execution action block limited specific events use conditional statement placed probe called predicate code action block follows c-like syntax limited set built functions following example probe defined whenever process pid 123456 enters read system call event happens script call built-in printf function print message output trace buffers first line action block c-style comment therefore execute probevue environment probes like sample written run without extensive testing normally required production system probevue environment protects user errant code resource hungry tracing frequently seen previous ibm tracing tools runtime compile feature probevue provides powerful ad hoc environment data gathering currently ibm provides following probe providers aix 6.1 syscall uft interval trace probevue probes begin end syscall provider defines probe points subset available system calls user function tracing uft probes defined entry points functions defined c c++ program syscall uft probes must include valid function prototype vue script function parameters entry probes return values syscall exit probes accessed interval probes fire timer defined 100 millisecond intervals trace provider allows probevue access traditional trace hooks finally probevue probes called begin end fire probevue environment starts exits probevue designed tool monitor operating system events vue language uses event driven style used describe process data derived events like dynamic tracing languages found unices vue language c-like syntax frequently presented context vue relationship c many parallels deviates significantly imperative nature c. contrasts similarities shown probevue used monitor applications written primarily c supports c data types well c data structures vue also supports string list time stamp data types string list types actually arrays time stamp high resolution representation point time type casting automatic type promotion operations mixed types similar c behavior well pointers arrays data structures behave probevue would c program key difference c pointers refer location memory referencing location another process space access memory necessary first copy memory location local probevue environment memory paged probevue force page fault access another difference size pointers c determined compile time probevue determined 32 64 bitness application probed floating point data types valid data types assignment probed process used floating point mathematical operations vue uses scoping rules similar c must also account externally derived nature much data probes result data classes available relevant probes portions view script basic classifications data follows vue operators follow c conventions closely exception used strings used strings operator performs concatenation == operator used comparisons vue allow definition user functions recursion looping constructs offer conditional if-then expressions within probe action block lightweight nature probevue prohibits vue script defining expensive looping extensive branching operations could degrade performance tentative tracing concept allows trace output block code labeled tentative output code later committed trace buffers visible output discarded works conceptually much like transaction controls sql vue script invoked interpreter magic set executable like shell script run input probevue command form command line parameter stdin input convention vue scripts .e filename extension vue language lacks aggregations instead uses list data type offers similar yet limited functionality equivalent product solaris called dtrace offers aggregation data type powerful set aggregating functions represent statistical data list data type offers basic aggregating functions single item opposed associative arrays aggregations dtrace offers list data type offers slight simplification keeping stats manually allow list reset say interval easily done using manual summaries basic types ibm committed associative arrays future versions vue language long development lead time dtrace probevue dtrace considerably probe point specifications ibm plans add considerable number new probe points future technology level releases aix 6.1 next major aix release
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Operating systems
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slackware slackware linux distribution created patrick volkerding 1993 originally based softlanding linux system slackware basis many linux distributions notably first versions suse linux distributions oldest distribution still maintained slackware aims design stability simplicity unix-like linux distribution makes modifications possible software packages upstream tries anticipate use cases preclude user decisions contrast modern linux distributions slackware provides graphical installation procedure automatic dependency resolution software packages uses plain text files small set shell scripts configuration administration without modification boots command-line interface environment many conservative simplistic features slackware often considered suitable advanced technically inclined linux users slackware available ia-32 x86_64 architectures port arm architecture slackware mostly free open source software formal bug tracking facility public code repository releases periodically announced volkerding formal membership procedure developers volkerding primary contributor releases name slackware stems fact distribution started private side project intended commitment prevent taken seriously first volkerding gave humorous name stuck even slackware became serious project slackware refers pursuit slack tenet church subgenius parody religion certain aspects slackware graphics reflect this—the pipe tux smoking influenced image j. r. bob dobbs head humorous reference church subgenius found many versions install.end text files indicate end software series setup program recent versions including slackware release 14.1 text rot13 obfuscated slackware originally derived softlanding linux system sls popular original linux distributions first offer comprehensive software collection comprised kernel basic utilities including x11 graphical interface tcp/ip uucp networking gnu emacs patrick volkerding started sls needing lisp interpreter school project named moorhead state university msu found clisp available linux downloaded sls run weeks later volkerding asked artificial intelligence professor msu show install linux home computers school volkerding made notes describing fixes issues found installing sls professor went applied changes new installation however took almost long took install sls professor asked install disks could adjusted fixes could applied installation start slackware volkerding continued making improvements sls fixing bugs upgrading software automatic installation shared libraries kernel image fixing file permissions short time volkerding upgraded around half packages beyond sls available volkerding intentions provide modified sls version public friends msu urged put sls modifications onto ftp server volkerding assumed sls would putting new version included things soon enough held weeks time many sls users internet asking sls new release eventually volkerding made post titled anyone want sls-like 0.99pl11a system received many positive responses discussion local sysadmin msu volkerding obtained permission upload slackware university ftp server first slackware release version 1.00 distributed july 17 1993 00:16:36 utc supplied 24 3½ floppy disk images announcement made volkerding watched flood ftp connections continually crashed server soon afterwards walnut creek cdrom offered additional archive space ftp servers size slackware quickly increased addition included software version 2.1 released october 1994 tripled comprise 73 1.44m floppy disk images 1999 slackware saw version jump 4 7 slackware version numbers lagging behind distributions led many users believe date even though bundled software versions similar volkerding made decision bump version marketing effort show slackware up-to-date linux distributions many release numbers 6 time chose 7 estimating distributions would soon release number april 2004 patrick volkerding added x.org server packages testing/ directory -current replacement xfree86 packages currently used request comments future x window system slackware month later switched xfree86 x.org server stating opinions 4 1 favor using x.org release default version x stated decision primarily technical one xfree86 proving cause compatibility problems slackware 10.0 first release x.org server march 2005 patrick volkerding announced removal gnome desktop environment development changelog stated consideration 4 years already projects provided complete version gnome slackware slackware provided volkerding stated future gnome support would rely community community responded october 2016 several active gnome projects slackware include cinnamon dlackware dropline gnome mate slackmate removal deemed significant linux community due prevalence gnome many distributions may 2009 patrick volkerding announced public development release official x86_64 variant called slackware64 maintained parallel ia-32 distribution slackware64 pure 64-bit distribution support running compiling 32-bit programs however designed multilib-ready eric hameleers one core slackware team members maintains multilib repository contains necessary packages convert slackware64 multilib enable running 32-bit software hameleers started 64-bit port diversion pain recovering surgery september 2008 volkerding tested port december 2008 impressed saw speed increases 20 40 percent benchmarks compared 32-bit version minimize extra effort maintaining versions parallel slackware build scripts called slackbuilds slowly transitioned supporting either architecture allowing one set sources versions slackware64 saw first stable release version 13.0 november 2013 release 14.1 june 2016 slackware saw 31-month gap releases marking longest span release history time development branch went without updates 47 days however april 21 2015 patrick volkerding apologized changelog absence updates stated development team used time get good work done 700 program changes listed changelog entry including many major library upgrades january 2016 volkerding announced reluctant addition pulseaudio primarily due bluez dropping direct alsa support v5.x various projects turn dropping support bluez v4.x knowing users would happy change stated bug reports complaints threats go changes culminated release slackware 14.2 june 2016 design philosophy slackware oriented toward simplicity software purity core design emphasizes lack change upstream sources many design choices slackware seen heritage simplicity traditional unix systems examples kiss principle context simple refers simplicity system design rather system usage thus ease use may vary users lacking knowledge command line interfaces classic unix tools may experience steep learning curve using slackware whereas users unix background may benefit less abstract system environment keeping slackware design philosophy spirit purity software slackware uses original configuration mechanisms supplied software authors however administrative tasks distribution-specific configuration tools delivered formal issue tracking system official procedure become code contributor developer project maintain public code repository bug reports contributions essential project managed informal way final decisions going included slackware release strictly remain slackware benevolent dictator life patrick volkerding first versions slackware developed patrick volkerding alone beginning version 4.0 official slackware announce files list david cantrell logan johnson part slackware team later announce statements release version 8.1 include chris lumens lumens johnson cantrell also authors first edition slackware linux essentials official guide slackware linux slackware website mentions chris lumens david cantrell slackware alumni worked full-time slackware project several years release notes slackware 10.0 10.1 volkerding thanks eric hameleers work supporting usb pci cardbus wireless cards starting version 12.0 second time team building around volkerding according release notes 12.2 development team consists seven people future versions added people since version 13.0 slackware team seems core members eric hameleers gives insight core team essay history slackware development written october 3–4 2009 shortly release version 13.0 slackware package management system collectively known pkgtools administer install upgrade remove packages local sources also uncompress create packages official tool update slackware network internet originally developed piter punk unofficial way keep slackware up-to-date officially included main tree slackware 12.2 included since slackware 9.1 package upgraded install new package old one remove files longer exist new package running confirms version numbers different thus allowing downgrading package desired slackware packages tarballs compressed using various methods starting 13.0 packages compressed using xz based lzma compression algorithm utilizing filename extension prior 13.0 packages compressed using gzip based deflate compression algorithm using extension support bzip2 lzma compression also added using filename extensions respectively although commonly used packages contain files program well additional metadata files used package manager package tarball contains full directory structure files meant extracted system root directory installation additional metadata files located special directory within tarball usually include file specifically formatted text file read package manager provide users description packaged software well file post-unpacking shell script allowing creation symbolic links preserving permissions startup files proper handling new configuration files aspects installation ca n't implemented via package directory structure package manager maintains directory package installed corresponding install log file lists package size compressed uncompressed software description full path files installed also maintains directory containing files allow proper removal installed symlinks package removed upgraded old install logs files moved respectively making possible review previous packages see removed package management system track manage dependencies however performing recommended full install dependencies stock packages met custom installations 3rd-party packages slackware relies user ensure system supporting system libraries programs required program since official lists dependencies stock packages provided users decide install custom installation install 3rd-party software need work possible missing dependencies since package manager n't manage dependencies install packages whether dependencies met user may find dependencies missing attempting use software slackware incorporate official tools resolve dependencies unofficial community-supported software tools provide function similar way apt debian-based distributions yum red hat-based distributions include official repositories slackware official packages slackware provides available installation media however many third-party repositories slackware standalone repositories others distributions slackware-based retain package compatibility slackware many searched using pkgs.org linux package search engine however mixing matching dependencies multiple repositories lead two packages require different versions dependency form dependency hell slackware wo n't provide dependency resolution packages however projects provide list dependencies included slackware files package commonly extension due possibility dependency issues many users choose compile programs using community-provided slackbuilds slackbuilds shell scripts create installable slackware package provided software tarball since slackbuilds scripts n't limited compiling program source also used repackage pre-compiled binaries provided projects distributions repositories proper slackware packages slackbuilds compile sources several advantages pre-built packages since build original author source code user trust third-party packager furthermore local compilation process allows machine-specific optimization comparison manual compilation installation software slackbuilds provide cleaner integration system utilizing slackware package manager slackbuilds come additional file metadata allows automated tools download source verify source corrupted calculate additional dependencies part slackware repositories include slackbuilds resulting slackware packages allowing users either build install pre-built package officially endorsed slackbuilds repository slackbuilds.org commonly referred sbo community-supported project offering slackbuilds building software included slackware users able submit new slackbuilds software site approved become package maintainer responsible providing updates slackbuild either fix issues build newer versions provided upstream ensure programs compiled used required dependencies software included slackware required documented available site submissions tested site administrators added repository administrators intend build process nearly identical way slackware official packages built mainly ensure volkerding sympathetic cause allows slackbuilds volkerding deems worthy pulled regular slackware minimal changes script also prevent users suggesting volkerding change scripts match sbo sbo provides templates slackbuilds additional metadata files encourage package maintainers deviate unless necessary two slackware team members eric hameleers robby workman repository pre-compiled packages along slackbuilds source files used create packages packages additional software included slackware felt worth time maintain packages used testbed future upgrades slackware notably hameleers provides ktown packages newer versions kde also maintains slackware multilib repository enabling slackware64 run compile 32bit packages slackware release policy follows feature stability based release cycle contrast time-bound e.g ubuntu rolling release e.g gentoo linux schemes linux distributions means set time expect release volkerding release next version feels suitable number changes previous version made changes lead stable environment stated patrick volkerding usually policy speculate release dates since — pure speculation always possible know long take make upgrades needed tie related loose ends things built upcoming release 'll uploaded -current tree throughout slackware history generally try deliver up-to-date software least annual basis however slackware 14.1 14.2 2-year gap releases inception 2014 2015 slackware least one release per year release activity peaked 1994 1995 1997 1999 three releases year starting version 7.1 june 22 2000 release progression became stable tended occur year since years two releases 2003 2005 2008 slackware latest 32bit x86 64bit x86_64 stable releases version 14.2 released june 30 2016 include support linux 4.4.14 volkerding also maintains testing/developmental version slackware called -current used bleeding edge configuration version eventually become next stable release point volkerding start new -current start developing next release slackware version generally known stable possible things break -current tends recommended production systems currently slackware officially stated support term policy however june 14 2012 notices appeared changelogs versions 8.1 9.0 9.1 10.0 10.1 10.2 11.0 12.0 stating effective august 1 2012 security patches would longer provided versions oldest release version 8.1 released june 18 2002 10 years support reaching eol later august 30 2013 announcements made changelogs 12.1 12.2 stating eol december 9 2013 stated changelog entries least 5 years support april 6 2018 versions 13.0 13.1 13.37 declared reaching eol july 5 2018 stated changelog entries least 7 years support 13.0 supported almost 9 years announcements slackware team versions slackware 14.0 eol official announcements versions prior 8.1 longer maintained effectively eol historically slackware concentrated solely ia-32 architecture releases available 32-bit however starting slackware 13.0 64-bit x86_64 variant available officially supported symmetrical development 32-bit platform prior release slackware64 users wanting 64-bit required use unofficial ports slamd64 slackware also available ibm s/390 architecture form slack/390 arm architecture slackware arm originally known 'armedslack ports declared official patrick volkerding however s/390 port still version 10.0 stable version 11.0 testing/developmental version updates since 2009 also may 7 2016 developer slackware arm announced 14.1 eol september 1 2016 development -current cease release 14.2 however support 14.2 maintained foreseeable future eol announcement 14.1 added changelog june 25 2016 july 2016 developer slackware arm announced development build tools enhanced reduce manual effort involved maintaining arm port proceeded announce 32-bit hardware floating port development port released august 2016 current form slackintosh unofficial port slackware new world macintosh powerpc architecture slackintosh final release 12.1 longer maintained slackware iso images installation downloaded free slackware website via bittorrent various ftp http mirrors 6-cd set single dual-dvd previously available order slackware official store store currently unavailable official statement return cd set targeted 32bit ia-32 platform also runs 64bit x86_64 processors 32-bit mode dvd contains 32bit 64bit versions distributions ports arm architecture ibm s/390 neither available cd/dvds iso images downloaded slackware s/390 installs dos partition floppy disk slackware arm distribute iso files arm devices boot cd dvd instead installed network using das u-boot tftp boot server mini-root filesystem slackware arm also installed pc running qemu using technique 2019 distrowatch ranks slackware 34 interest appears peaked 2002 slackware rank reached 7 gradually slipped top 10 2010 appears stabilized around current rank 2015 however since distrowatch tracks visitors various distributions pages state ranking n't always correlate usage distribution popularity distribution site rankings used measure market share distributions linux distributions slackware official tracking system total unique installs active users
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Computer architecture
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variable assembly language variable assembly language val computer-based control system language designed specifically use unimation inc. industrial robots val robot language permanently stored part val system includes programming language used direct system individual applications val language easy understand syntax uses clear concise generally self-explanatory instruction set commands communications robot consist easy understand word number sequences control programs written computer controls robot real-time system val continuous trajectory computation permits complex motions executed quickly efficient use system memory reduction overall system complexity val system continuously generates robot control commands simultaneously interact human operator permitting on-line program generation modification convenient feature val ability use libraries manipulation routines thus complex operations may easily quickly programmed combining predefined subtasks val language consists monitor commands program instructions monitor commands used prepare system execution user-written programs program instructions provide repertoire necessary create val programs controlling robot actions following terms frequently used val related operations val monitor administrative computer program oversees operation system accepts user input initiates appropriate response follows instructions user-written programs direct robot performs computations necessary control robot val editor aid entering information computer system modifying existing text used enter modify robot control programs list instructions telling computer something val programs written system users describe tasks robot perform location position object space orientation object locations used define positions orientations robot tool assume program execution several conventions apply numerical values supplied val commands instructions preceding monitor-command description two symbols indicating command typed user dot signifies command performed val top-level monitor mode user program executed system prompt dot asterisk indicates command performed time val executing program system prompt asterisk symbols present command executed either case monitor commands program instructions abbreviated entering monitor command program instruction function name abbreviated many characters necessary make name unique commands instructions angle brackets used enclose item describes actual argument appear thus programmer supply appropriate item position entering command instruction note brackets used clarification never included part command instruction many val commands instructions optional arguments notations optional arguments enclosed square brackets comma following argument comma must retained argument omitted unless nothing follows example monitor base command form specify 300-millimeter change z direction command could entered following ways note commas preceding number 300 must present correctly relate number z-direction change like angle brackets square brackets never entered part command instruction several types numerical arguments appear commands instructions type restrictions values accepted val following rules observed nearest representable value function val regulate control robot system following user commands instructions addition compact stand-alone system val designed highly interactive minimize programing time provide many programming aids possible standard val system uses operator console terminal manual control box input commands data user operator console serves primary communication device either direct play terminal printing terminal interaction devices automated cell typically handled monitoring input channels switching outputs means robot control modest cell without need programmable devices controller two levels operation prom memory retains contents finitely thus val immediately available controller switched monitor responsible control robot commands come manual control unit system terminal programs increase versatility flexibility val monitor perform commands even user program executed commands processed way include controlling status system defining robot locations storing retrieving information floppy disk creating editing robot control programs
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Programming language topics
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linear tape file system linear tape file system ltfs file system allows files stored magnetic tape accessed similar fashion disk removable flash drives requires specific format data tape media software provide file system interface data technology based around self-describing tape format developed ibm adopted lto consortium 2010 magnetic tape data storage used 50 years typically hold file metadata form easy access modify independent file content data often external databases used maintain file metadata file names timestamps directory hierarchy hold data external databases generally designed interoperability tapes might might contain index content unix-like systems tar interoperable standard well-suited allow modification file metadata independent modifying file content data maintain central index files provide filesystem interface characteristics ltfs technology first implemented ibm prototype running linux mac os x 2008/2009 prototype demonstrated nab 2009 based feedback initial demonstration experience within ibm filesystem overhauled preparation release product ltfs development team worked vendors lto tape products hp quantum build support understanding ltfs format filesystem implementation leading public release ltfs format specification filesystem implementation released april 12 2010 support ibm hp quantum lto consortium ltfs v2.0.0 released march 2011 improving text clarify remove ambiguity also added support sparse files persistent file identifiers virtual extended attributes filesystem metadata control defined minimum recommended blocksize values ltfs volumes compatibility across various hba hardware implementations version 2.0.0 defines rules version number may change future compatibility maintained across varying implementations implementations must august 2012 snia announced forming twg technical work group continue technical development specification ltfs format specification v 2.1 baseline technical work standards accreditation process snia ltfs twg members include hp ibm oracle quantum ltfs make tape appear behave like disk change fundamentally sequential nature tape files always appended end tape file modified overwritten removed volume associated tape blocks used freed simply marked unavailable used volume capacity recovered data deleted capacity recovered whole tape reformatted spite disadvantages several uses cases ltfs formatted tape superior disk data storage technologies lto seek times range 10 100 seconds streaming data transfer rate match exceed disk data transfer rates additionally lto cartridges easily transportable hold far data removable data storage format ability copy large file large selection files 1.5tb lto-5 2.5tb lto_6 ltfs formatted tape allows easy exchange data collaborator saving archival copy since ltfs open standard ltfs formatted tapes usable wide variety computing systems ibm linear tape file system single drive edition initially released ibm long term file system allows tapes formatted ltfs volume volumes mounted users applications access files directories stored tape directly including drag-and-drop files ibm linear tape file system library edition ltfs-le product allows ltfs volumes used tape library ltfs-formatted tape cartridge library appears separate folder filesystem mount point user application navigate folders access files stored tape ltfs-le software automatically controls tape library robotics load unload necessary ltfs volumes oracle free open source storagetek linear tape file system ltfs open edition software claimed first store 8.5tb native capacity single cartridge supports oracle ’ midrange storagetek lto 5 lto 6 tape drives hp ibm well oracle ’ storagetek t10000c t10000d tape drives oracle ’ storagetek ltfs-le software offering supports storagetek sl8500 modular library system storagetek sl3000 modular library system storagetek sl150 modular tape hp linear tape file system hp ltfs hp implementation free open source software application quantum corporation provides ltfs solution windows linux mac os x support scalar ltfs appliance file system presents quantum tape library nas share appliance makes files viewable resided local disk allows users drag drop files directly tape cartridge implementations
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Computer file systems
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cloudshare cloudshare cloud computing provider company formerly structures founded january 2007 israel headquartered san francisco california cloudshare combines aspects virtualization cloud computing advanced features offer software service saas similar virtual lab automation cloudshare makes full-featured virtual enterprise environments available online on-demand applications including developing testing pre-sales demos proofs-of-concept evaluations technical training development certification hardware software channel enablement customers create multi-machine environments cloud upload existing virtual machines cloudshare supports hypervisors vmware oracle virtualbox operating systems windows 7 ubuntu provides templates new machines operating systems even software microsoft sharepoint 2010 microsoft office 2010 ruby rails preinstalled created environments consist single virtual machine multiple networked machines able operate seamlessly user ’ physical pc workstation environments saved replicated shared additional users free interact independent replica “ snapshot ” cloudshare founded tel aviv israel january 2007 avner rosenan ophir kra-oz zvi guterman company originally named structures 2009 cloudshare moved headquarters san mateo california december 2009 cloudshare closed series b round funding receiving 10 million sequoia capital charles river ventures gemini capital bringing total venture capital funding 16 million 2014 zvi guterman bought company back sequoia capital took private
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Distributed computing architecture
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