text
stringlengths 6
1.88M
| source
stringclasses 13
values |
|---|---|
arptables arptables computer software utility network administrator tool maintaining address resolution protocol arp packet filter rules linux kernel firewall modules tools may used create update view tables contain filtering rules similarly iptables program developed popular application creation filter configurations prevent arp spoofing linux kernel 2.4 offers two arp filtering chains input output linux kernel 2.6 adds third forward applied bridging packets
|
Computer security
|
scality scality global company based san francisco california develops software-defined object storage scality scale-out object storage software platform called ring company commercial product scality ring software deploys industry-standard x86 servers store objects files scality also offers number open source tools called zenko including zenko cloudserver compatible amazon s3 api scality founded 2009 jérôme lecat giorgio regni daniel binsfeld serge dugas brad king scality raised 7 million venture capital funding march 2011 c-round 22 million announced june 2013 led menlo ventures iris capital participation fsn pme existing investors including idinvest partners omnes capital galileo partners scality raised 45 million august 2015 series funding led menlo ventures participation existing investors one new strategic investor broadband tower 2016 hpe made strategic investment company april 2018 company announced 60 million round funding scality announced refreshed brand along global distribution agreement hp october 2014 scality added dell cisco global resellers 2015 scality principal product scale-out object storage software platform known ring scality ring delivers petabyte-scale software-defined storage designed use commodity hardware characterized cost-effective scaling performance auto-recovery scality ring multitier architecture scale thousands servers 100 petabytes single global namespace allows customers deploy performance-optimized capacity-optimized storage varied data durability levels small large object file support single global namespace object storage one fastest growing segments enterprise storage market according idc report “ worldwide file – object – based storage forecast 2016 – 2020 ” idc us41685816 september 2016 estimated object-based storage capacity expected grow cagr 30.7 percent 2016 2020 reaching 293.7eb 2020.the scality ring software turns standard x86 servers web-scale storage ring store amount data type incredible efficiency 100 availability guaranteed—all reducing costs much 90 legacy systems zenko scality open source multi-cloud data controller zenko integrates data managed on-premises services available public clouds zenko cloudserver formerly scality s3 server amazon web services simple storage service-compatible open source object storage server code written node.js single instance running docker container uses docker volumes persistent storage cloudserver uses code scality ring s3 interface includes apache 2.0 license note distributed system paid version s3 enterprise however level compatibility s3 interface scality ring zenko orbit cloud-based portal data placement workflows global metadata search product enables asynchronous replication clouds scality recognized consistently years object-based storage idc gartner first magic quadrant distributed file systems object storage scality ranked leader scality 2014 storage system software finalist storage magazine 2017 scality ranked leader gartner magic quadrant distributed file systems object storage
|
Computer file systems
|
prototype verification system prototype verification system pvs specification language integrated support tools automated theorem prover developed computer science laboratory sri international menlo park california pvs based kernel consisting extension church theory types dependent types fundamentally classical typed higher-order logic base types include uninterpreted types may introduced user built-in types booleans integers reals ordinals type-constructors include functions sets tuples records enumerations abstract data types predicate subtypes dependent types used introduce constraints constrained types may incur proof obligations called type-correctness conditions tccs typechecking pvs specifications organized parameterized theories system implemented common lisp released gnu general public license gpl
|
Programming language topics
|
security hacker security hacker someone explores methods breaching defenses exploiting weaknesses computer system network hackers may motivated multitude reasons profit protest information gathering challenge recreation evaluate system weaknesses assist formulating defenses potential hackers subculture evolved around hackers often referred computer underground longstanding controversy surrounds meaning term hacker controversy computer programmers reclaim term hacker arguing refers simply someone advanced understanding computers computer networks cracker appropriate term break computers whether computer criminals black hats computer security experts white hats 2014 article noted ... black-hat meaning still prevails among general public computer security hacker someone focuses security mechanisms computer network systems including endeavor strengthen mechanisms often used mass media popular culture refer seek access despite security measures media portrays 'hacker villain nevertheless parts subculture see aim correcting security problems use word positive sense white hat name given ethical computer hackers utilize hacking helpful way white hats becoming necessary part information security field operate code acknowledges breaking people computers bad discovering exploiting security mechanisms breaking computers still interesting activity done ethically legally accordingly term bears strong connotations favorable pejorative depending context subculture around hackers termed network hacker subculture hacker scene computer underground initially developed context phreaking 1960s microcomputer bbs scene 1980s implicated alt.2600 newsgroup 1980 article august issue psychology today commentary philip zimbardo used term hacker title hacker papers excerpt stanford bulletin board discussion addictive nature computer use 1982 film tron kevin flynn jeff bridges describes intentions break encom computer system saying 've little hacking clu software uses 1983 hacking sense breaking computer security already use computer jargon public awareness activities however release film wargames year featuring computer intrusion norad raised public belief computer security hackers especially teenagers could threat national security concern became real year gang teenage hackers milwaukee wisconsin known 414s broke computer systems throughout united states canada including los alamos national laboratory sloan-kettering cancer center security pacific bank case quickly grew media attention 17-year-old neal patrick emerged spokesman gang including cover story newsweek entitled beware hackers play patrick photograph cover newsweek article appears first use word hacker mainstream media pejorative sense pressured media coverage congressman dan glickman called investigation began work new laws computer hacking neal patrick testified u.s. house representatives september 26 1983 dangers computer hacking six bills concerning computer crime introduced house year result laws computer criminality white hat grey hat black hat hackers try distinguish depending legality activities moral conflicts expressed mentor hacker manifesto published 1986 phrack use term hacker meaning computer criminal also advanced title stalking wily hacker article clifford stoll may 1988 issue communications acm later year release robert tappan morris jr. so-called morris worm provoked popular media spread usage popularity stoll book cuckoo egg published one year later entrenched term public consciousness several subgroups computer underground different attitudes use different terms demarcate try exclude specific group agree eric s. raymond author new hacker dictionary advocates members computer underground called crackers yet people see hackers even try include views raymond see wider hacker culture view raymond harshly rejected instead hacker/cracker dichotomy emphasize spectrum different categories white hat grey hat black hat script kiddie contrast raymond usually reserve term cracker malicious activity according ralph d. clifford cracker cracking gain unauthorized access computer order commit another crime destroying information contained system subgroups may also defined legal status activities white hat hacker breaks security non-malicious reasons either test security system perform penetration tests vulnerability assessments client working security company makes security software term generally synonymous ethical hacker ec-council among others developed certifications courseware classes online training covering diverse arena ethical hacking black hat hacker hacker violates computer security little reason beyond maliciousness personal gain moore 2005 term coined richard stallman contrast maliciousness criminal hacker versus spirit playfulness exploration hacker culture ethos white hat hacker performs hacking duties identify places repair means legitimate employment black hat hackers form stereotypical illegal hacking groups often portrayed popular culture epitome public fears computer criminal grey hat hacker lies black hat white hat hacker grey hat hacker may surf internet hack computer system sole purpose notifying administrator system security defect example may offer correct defect fee grey hat hackers sometimes find defect system publish facts world instead group people even though grey hat hackers may necessarily perform hacking personal gain unauthorized access system considered illegal unethical social status among hackers elite used describe skilled newly discovered exploits circulate among hackers elite groups masters deception conferred kind credibility members script kiddie also known skid skiddie unskilled hacker breaks computer systems using automated tools written others usually black hat hackers hence term script i.e computer script automates hacking kiddie i.e kid child—an individual lacking knowledge experience immature usually little understanding underlying concept neophyte newbie noob someone new hacking phreaking almost knowledge experience workings technology hacking blue hat hacker someone outside computer security consulting firms used bug-test system prior launch looking exploits closed microsoft also uses term bluehat represent series security briefing events hacktivist hacker utilizes technology publicize social ideological religious political message hacktivism divided two main groups intelligence agencies cyberwarfare operatives nation states groups hackers carry organized criminal activities profit typical approach attack internet-connected system order several recurring tools trade techniques used computer criminals security experts security exploit prepared application takes advantage known weakness common examples security exploits sql injection cross-site scripting cross-site request forgery abuse security holes may result substandard programming practice exploits would able used file transfer protocol ftp hypertext transfer protocol http php ssh telnet web pages common web site web domain hacking tools procedures computer underground produced specialized slang 1337speak members often advocate freedom information strongly opposing principles copyright well rights free speech privacy writing software performing activities support views referred hacktivism consider illegal cracking ethically justified goals common form website defacement computer underground frequently compared wild west common hackers use aliases conceal identities computer underground supported regular real-world gatherings called hacker conventions hacker cons events include summercon summer def con hohocon christmas shmoocon february blackhat chaos communication congress athcon hacker halted hope local hackfest groups organize compete develop skills send team prominent convention compete group pentesting exploit forensics larger scale hacker groups became popular early 1980s providing access hacking information resources place learn members computer bulletin board systems bbss utopias provided platforms information-sharing via dial-up modem hackers could also gain credibility affiliated elite groups maximum imprisonment one year fine fourth category commonly known computer fraud abuse act prohibits unauthorized access damage protected computers protected computers defined maximum imprisonment fine violations computer fraud abuse act depends severity violation offender history violations act notable hacker-oriented print publications phrack hakin9 information contained hacker magazines ezines often outdated time published enhanced contributors reputations documenting successes hackers often show interest fictional cyberpunk cyberculture literature movies adoption fictional pseudonyms symbols values metaphors works common
|
Computer security
|
ios jailbreaking ios jailbreaking privilege escalation apple device purpose removing software restrictions imposed apple ios tvos watchos operating systems typically done using series kernel patches jailbreaking permits root access ios allowing installation software unavailable official apple app store many types jailbreaking available different versions apple publicly disapproves jailbreaking apple implemented hardware software fixes vulnerabilities used jailbreaks meaning many versions ios jailbroken immediately analogous rooting android although software unavailable google play installed android without rooting one reasons jailbreaking expand feature set limited apple app store apple checks apps compliance ios developer program license agreement accepting distribution app store however reasons banning apps limited safety security may regarded arbitrary capricious one case apple mistakenly banned app pulitzer-winning cartoonist violated developer license agreement specifically bans apps contain content ridicules public figures access banned apps users rely jailbreaking circumvent apple censorship content features jailbreaking permits downloading programs approved apple user interface customization tweaks since software programs available apt installer.app legacy required adhere app store guidelines many typical self-contained apps instead extensions customization options ios apps commonly called tweaks users install programs purposes including personalization customization interface tweaks developed developers designers adding desired features fixing annoyances making development work device easier providing access filesystem command-line tools many chinese ios device owners also jailbreak phones install third-party chinese character input systems easier use apple jailbreaking also opens possibility using software unofficially unlock carrier-locked iphones used carriers software-based unlocks available since september 2007 tool applying specific iphone model baseband version multiple models versions includes iphone 4s iphone 4 iphone 3gs iphone 3g models example unlocking iphone jailbreak utility would redsn0w software iphone users able create custom ipsw unlock device moreover unlocking process options install cydia ipad baseband computer criminals may jailbreak iphone install malware target jailbroken iphones malware installed easily italian cybersecurity company hacking team sells hacking software law enforcement agencies advised police jailbreak iphones allow tracking software installed iphones installation consumer software generally restricted installation app store jailbreaking therefore allows installation pirated applications suggested major motivation apple prevent jailbreaking protect income app store including third-party developers allow buildup sustainable market third-party software however installation pirated applications also possible without jailbreaking taking advantage enterprise certificates facilitate distribution modified pirated releases popular applications jailbroken device booting loads apple kernel initially device exploited kernel patched every time turned many different types jailbreaks come years untethered jailbreak jailbreak require assistance reboots kernel patched without help computer application jailbreaks uncommon take significant amount reverse engineering create tethered jailbreak opposite untethered jailbreak sense computer required boot device boot using tethered jailbreak user still able restart/kill springboard without needing reboot mix untethered tethered jailbreak also option namely semi-tethered type jailbreak allows user reboot patched kernel non-jailbroken functions still run making phone call texting using app able patched kernel run modified code device must booted using computer type jailbreak become popular recent years semi-untethered variant type jailbreak like semi-tethered jailbreak device reboots longer patched kernel kernel patched without using computer kernel usually patched using application installed device recent jailbreaks semi-untethered variant jailbreaking ios devices sometimes compared rooting android devices although concepts involve privilege escalation differ scope android devices allow users modify replace operating system unlocking bootloader moreover nearly android phones option allow user install unknown 3rd-party apps exploit needed normal sideloading ios engineered security measures including locked bootloader prevent users modifying operating system prevent apps gaining root privileges jailbreaking ios device defeat security measures presents significant technical challenge violates apple end-user license agreement ios 2015 sideloading apps general difficult individual users requiring purchase developer membership corporations could install private applications onto corporate phones 2015 became free users however requires basic understanding xcode compiling ios apps apps installed way restrictions apps addition alternative app stores utilising enterprise certificates sprung offering modified pirated releases popular ios applications video games either previously released cydia unavailable app store due complying apple developer guidelines first iphone worm ikee appeared early november 2009 created 21-year-old australian student town wollongong told australian media created worm raise awareness security issues jailbreaking allows users install ssh service users leave default insecure state month f-secure reported new malicious worm compromising bank transactions jailbroken phones netherlands similarly affecting devices owner installed ssh without changing default password 2010 blogger john gruber close apple said users misunderstood jailbreak exploits serious appear commented odd press mostly covering 'jailbreaking convenient rather 'remote code exploit wild pointing exploit allowed creator malicious website take control iphones accessing restoring device itunes removes jailbreak however generally updates device latest possibly non-jailbreakable version due apple use shsh blobs many applications aim prevent restoring devices version currently running whilst removing jailbreaks examples succession semi-restore cydia eraser 2012 forbes staff analyzed ucsb study 1,407 free programs available apple third party source 1,407 free apps investigated 825 downloaded apple app store using website app tracker 526 bigboss cydia default repository 21 official apps tested leaked device id 4 leaked location unofficial apps leaked 4 0.2 respectively 0.2 apps cydia leaked photos browsing history app store leaked none unauthorized apps tended respect privacy better official ones also program available cydia called privacy allows user control upload usage statistics remote servers august 2015 keyraider malware discovered affects jailbroken iphones apple released various updates ios patch exploits used jailbreak utilities includes patch released ios 6.1.3 software exploits used original evasi0n ios 6–6.1.2 jailbreak ios 7.1 patching evasi0n 7 jailbreak ios 7–7.0.6-7.1 beta 3 bootroom exploits exploits found hardware device patched apple system updates fixed hardware revisions new chips new hardware entirety occurred iphone 3gs 2009 july 15 2011 apple released new ios version closed exploit used jailbreakme 3.0 german federal office information security reported jailbreakme uncovered critical weakness information could stolen malware unwillingly downloaded ios users clicking maliciously crafted pdf files apple released fix security hole jailbreak users access fix published developer jailbreakme january 27 2015 apple released ios 8.1.3 patched exploits used jailbreak ios 8.0-8.1.2 possible jailbreak ios 8.3 update ios 9.1 update october 21 2015 included patch pangu ios 9.0-9.0.2 jailbreak august 13 2015 apple updated ios 8.4.1 patching taig exploit pangu taig teams said working exploiting ios 8.4.1 pangu demonstrated chances wwdc 2015 september 16 2015 ios 9 announced made available released new rootless security system dubbed heavy blow jailbreaking community october 21 2015 seven days pangu ios 9.0-9.0.2 jailbreak release apple pushed ios 9.1 update contained patch rendered nonfunctional august 4 2016 apple released ios version 9.3.4 patch semi-untethered jailbreak 64-bit devices august 25 2016 apple released ios version 9.3.5 patch three important vulnerabilities used secret jailbreak pegasus malware nso group january 23 2017 apple released ios 10.2.1 patch jailbreak exploits released google yalu ios 10 jailbreak created luca todesco december 2 2017 ios 11.2 released included patch async_wake exploit ian beer google project zero may 29 2018 ios 11.4 released including patch 2 exploits empty_list multi_path ian beer google project zero january 22 2019 ios 12.1.3 released including patch exploit voucher_swap found independently brandon azad google project zero zhuo liang qihoo 360 nirvan team may 13 2019 ios 12.3 released including patch exploit sock_puppet ned williamson google project zero however 18th august 2019 bacame known apple accidentally reintroduced vulnerabilities ios 12.4 making possible jailbreak 12.4 exploits pre-12.3 versions apple n't patched 12.4.1 version yet legal status jailbreaking affected laws regarding circumvention digital locks laws protecting digital rights management drm mechanisms many countries laws countries laws including exceptions jailbreaking international treaties influenced development laws affecting jailbreaking 1996 world intellectual property organization wipo copyright treaty requires nations party treaties enact laws drm circumvention american implementation digital millennium copyright act dmca includes process establishing exemptions non-copyright-infringing purposes jailbreaking 2001 european copyright directive implemented treaty europe requiring member states european union implement legal protections technological protection measures copyright directive includes exceptions allow breaking measures non-copyright-infringing purposes jailbreaking run alternative software member states vary implementation directive apple technically support jailbreaking violation eula jailbreaking communities generally legally threatened apple least two prominent jailbreakers given positions apple albeit least one case temporary one apple also regularly though possibly somewhat jokingly thanked jailbreak communities detecting security holes ios release notes apple support article concerning jailbreaking claims may deny service iphone ipad ipod touch installed unauthorized software therefore anyone jailbroken warranty may may get support apple considering assistance jailbreaking 2010 electronic frontiers australia said unclear whether jailbreaking legal australia anti-circumvention laws may apply laws strengthened copyright amendment act 2006 november 2012 canada amended copyright act new provisions prohibiting tampering drm protection exceptions including software interoperability jailbreaking device run alternative software form circumventing digital locks purpose software interoperability several efforts 2008–2011 amend copyright act bill c-60 bill c-61 bill c-32 prohibit tampering digital locks along initial proposals c-11 restrictive bills set aside 2011 michael geist canadian copyright scholar cited iphone jailbreaking non-copyright-related activity overly-broad copyright act amendments could prohibit india copyright law permits circumventing drm non-copyright-infringing purposes parliament introduced bill including drm provision 2010 passed 2012 copyright amendment bill 2012 india signatory wipo copyright treaty requires laws drm circumvention listed us special 301 report priority watch list applied pressure develop stricter copyright laws line wipo treaty new zealand copyright law allows use technological protection measure tpm circumvention methods long use legal non-copyright-infringing purposes law added copyright act 1994 part copyright new technologies amendment act 2008 jailbreaking might legal singapore done provide interoperability circumvent copyright tested court law copyright related rights regulations 2003 makes circumventing drm protection measures legal purpose interoperability copyright infringement jailbreaking may form circumvention covered law tested court competition laws may also relevant main law affects legality ios jailbreaking united states 1998 digital millennium copyright act dmca says person shall circumvent technological measure effectively controls access work protected dmca since may apply jailbreaking every three years law allows public propose exemptions legitimate reasons circumvention last three years approved 2010 2012 u.s copyright office approved exemptions allowed smartphone users jailbreak devices legally 2015 copyright office approved expanded exemption also covers all-purpose mobile computing devices tablets still possible apple may employ technical countermeasures prevent jailbreaking prevent jailbroken phones functioning unclear whether legal traffic tools used make jailbreaking easy 2010 apple announced jailbreaking violate warranty may affected magnuson-moss warranty act 1975 2007 tim wu professor columbia law school argued jailbreaking apple superphone legal ethical plain fun wu cited explicit exemption issued library congress 2006 personal carrier unlocking notes locks used wireless carriers limit ability subscribers switch carriers business decision nothing whatsoever interests protected copyright thus implicate dmca wu claim exemption applies help others unlock device traffic software 2010 response request electronic frontier foundation u.s copyright office explicitly recognized exemption dmca permit jailbreaking order allow iphone owners use phones applications available apple store unlock iphones use unapproved carriers apple previously filed comments opposing exemption indicated considered jailbreaking violation copyright implication prosecutable dmca apple request define copyright law include jailbreaking violation denied part 2009 dmca rulemaking ruling library congress affirmed july 26 2010 jailbreaking exempt dmca rules respect circumventing digital locks dmca exemptions must reviewed renewed every three years else expire october 28 2012 us copyright office released new exemption ruling jailbreaking smartphones continued legal circumvention accomplished sole purpose enabling interoperability lawfully obtained software applications computer programs telephone handset however u.s copyright office refused extend exemption tablets ipads arguing term tablets broad ill-defined exemption class devices could unintended side effects copyright office also renewed 2010 exemption unofficially unlocking phones use unapproved carriers restricted exemption phones purchased january 26 2013 days original iphone became available july 2007 developers released first jailbreaking tool soon jailbreak-only game app became available october 2007 jailbreakme 1.0 also called appsnapp allowed people jailbreak iphone os 1.1.1 iphone ipod touch included installer.app way get software jailbroken device february 2008 zibri released ziphone tool jailbreaking iphone os 1.1.3 iphone os 1.1.4 iphone dev team affiliated apple released series free desktop-based jailbreaking tools july 2008 released version pwnagetool jailbreak new iphone 3g iphone os 2.0 well ipod touch newly including cydia primary third-party installer jailbroken software pwnagetool continues updated untethered jailbreaks newer ios versions november 2008 iphone dev team released quickpwn jailbreak iphone os 2.2 iphone ipod touch options enable past functionality apple disabled certain devices apple released ios 3.0 june 2009 dev team published redsn0w simple jailbreaking tool mac windows also updated pwnagetool primarily intended expert users making custom firmware mac continues maintain redsn0w jailbreaking versions ios 4 ios 5 devices george hotz developed first iphone unlock 2009 released jailbreaking tool iphone 3gs iphone os 3.0 called purplera1n blackra1n iphone os version 3.1.2 3rd generation ipod touch devices october 2010 released limera1n low-level boot rom exploit permanently works jailbreak iphone 4 used part tools including redsn0w nicholas allegra better known comex released program called spirit may 2010 spirit jailbreaks devices including iphones running iphone os 3.1.2 3.1.3 ipad running ios 3.2 august 2010 comex released jailbreakme 2.0 first web-based tool jailbreak iphone 4 ios 4.0.1 july 2011 released jailbreakme 3.0 web-based tool jailbreaking devices certain versions ios 4.3 including ipad 2 first time ios 4.3.3 2011 jailbreakme 3.0 used flaw pdf file rendering mobile safari chronic dev team initially released greenpois0n october 2010 desktop-based tool jailbreaking ios 4.1 later ios 4.2.1 devices including apple tv well ios 4.2.6 cdma verizon iphones december 2011 redsn0w included corona untether pod2g ios 5.0.1 iphone 3gs iphone 4 ipad 1st generation ipod touch 3rd 4th generation june 2012 redsn0w also includes rocky racoon untether pod2g ios 5.1.1 iphone ipad ipod touch models support ios 5.1.1 iphone dev team chronic dev team pod2g collaborated release absinthe january 2012 desktop-based tool jailbreak iphone 4s first time ipad 2 second time ios 5.0.1 devices also ios 5.0 iphone 4s may 2012 released absinthe 2.0 jailbreak ios 5.1.1 untethered iphone ipad ipod touch models support ios 5.1.1 including jailbreaking third-generation ipad first time hackers together called evad3rs released ios 6.x jailbreak tool called evasi0n available linux os x windows monday february 4 2013 noon eastern standard time due high volume interest downloading jailbreak utility site initially gave anticipating users download errors apple upgraded software ios 6.1.3 permanently patched evasi0n jailbreak april 2013 latest versions sn0wbreeze released added support tethered jailbreaking a4 devices i.e devices newer iphone 4 ipad 1st generation ipod touch 4th generation december 22 2013 evad3rs released new version evasi0n supports jailbreaking ios 7.0.x known evasi0n7 december 30 2013 winocm ih8sn0w squiffypwn released p0sixspwn untethering devices ios 6.1.3 – 6.1.5 initially necessary jailbreak tethered using redsn0w install p0sixpwn cydia days later january 4 2014 team released version p0sixpwn jailbreaking using computer ios 7.1 patched exploits used evasi0n7 june 23 2014 pangu chinese untethered jailbreak released ios 7.1 october 22 2014 pangu team released pangu8 jailbreak devices running ios 8-8.1 first versions bundle cydia ios 8 compatible version cydia time november 29 2014 taig team released jailbreak tool called taig devices running ios 8.0-8.1.1 december 10 2014 app updated include support ios 8.1.2 july 3 2015 taig 2.3.0 released includes support ios 8.0-8.4 10 september 2015 6 days ios 9 released ih8sn0w demonstrated working exploit twitter page linking youtube video october 14 2015 pangu team released pangu 9 jailbreak tool ios 9.0 9.0.2 march 11 2016 pangu team updated tool support ios 9.1 64-bit devices july 17 2016 pangu team released pangu93 semi-untethered jailbreak tool ios 9.2-9.3.3 first semi-untethered jailbreak time made within sideloaded app included support 64bit devices mid-march 2017 jk9357 aka realkjcmember part kjc kim jong cracks hacking team released first semi-untethered jailbreak 32bit devices 9.1-9.3.4 jailbreak made use pegasus vulnerabilities december 21 2016 well-known hacker luca todesco released beta semi-untethered jailbreak tool ios 10.1 known yalu+mach_portal select 64-bit ios devices jailbreak made use ian beer google project zero mach_portal exploit version extremely unstable meant developers january 26 2017 help marco grassi stable version ios 10.2 released eventually supporting 64-bit ios devices except iphone 7 7 plus supported older unstable version 10.1.1 jailbreak made use ian beer project zero extra_recipe exploit jailbreaks installed computer application known cydia impactor allows signing apps app store todesco said newer version would eventually updated support iphone 7 7 plus ios 10.1.1 however left jailbreaking scene march 28 abandoning jailbreaks released august 6 2017 siguza tihmstar released semi-untethered phoenix jailbreak 32-bit devices ios 9.3.5 september 19 2017 tihmstar released etasonjb jailbreak 32-bit devices ios 8.4.1 exploit found users 9.3.5 phoenix jailbreak could downgrade 8.4.1 without use shsh blobs 8.4.1 unsigned version ios october 15 2017 hacker abraham masri known twitter cheesecakeufo released saïgon jailbreak 64-bit devices ios 10.2.1 december 6 2017 abraham masri released houdini first semi-jailbreak ios 10 compatible ios 10.x 10.3.2 64-bit devices application allows installation themes resolution changes etc basic cydia repos untethered needs run exploit install content tool updated beta revision 1 adding compatibility ios 11 11.1.2 december 11 2017 ian beer released async_wake ios 11.0 11.1.2 exploit allows tfp0 exploit updated allowed jailbreak apps jailed devices filzajailed filzaescaped allows root access jailed device mterminal-jailed applebetas allows execution commands jailed device torngat 1gamerdev tweak manager set boot logo change resolution disable ota updates jailed device december 23 2017 abraham masri released to.panga ios 11 11.1.2 wip jailbreak developers based async_wake exploit ian beer cydia included since jailbreak used kppless exploit cydia substrate rewritten abraham masri since stated project would n't updated due tools goal december 24 2017 tihmstar released h3lix semi-untethered jailbreak 32-bit devices compatible ios 10 versions shortly release h3lix tihmstar siguza released doubleh3lix semi-untethered jailbreak 64bit devices excluding iphone 7 ios 10.x december 26 2017 hacker jonathan levin known twitter morpheus____ released liberios wip developer-only jailbreak based async_wake exploit ian beer ios 11.0 ios 11.1.2 jonathan levin later stated liberios would officially released cydia january 29 2018 zimperium whose goal assess issues locate possible ios sandbox escape released two crucial bugs one major vulnerability leads execution arbitrary code different crucial daemons found ios 11.2 11.2.2 second bug full relative aslr bypass control stack corebluetooth leads memory corruption also 11.2 – 11.2.2 february 26 2018 developer coolstar known twitter coolstarorg released public version electra jailbreak ios devices 11.0–11.1.2 jailbreak uses kppless exploit cydia substrate updated ios 11 electra uses substrate alternative known substitute june 6 2018 abraham masri released update houdini first semi-jailbreak tool updated beta 3 revision 1 adding compatibility ios 11 11.3.1 july 6 2018 developer coolstar known twitter coolstarorg released public version electra jailbreak ios devices 11.0-11.3.1 jailbreak uses kppless exploit cydia substrate updated ios 11 electra uses substrate alternative known substitute august 17 2018 developer ben sparkes released public version meridian jailbreak ios versions 10.x 64-bit devices september 3 2018 web-based jailbreak called totally spyware released unknown user named jakeblair420 eventually came developed foxletfox ben sparkes littlelailo siguza stek29 based works 5aelo ian beer niklas b jamie bishop lucas todesco realkjcmember sam bingner sticktron theninjaprawn tihmstar xerub used webkit-based exploit bootstrap either meridian doubleh3lix october 14 2018 former electra team member developer pwn20wnd known twitter pwn20wnd ref name= https //twitter.com/pwn20wnd https //twitter.com/pwn20wnd /ref released public version unc0ver jailbreak ios devices 11.0–11.4.1 jailbreak uses three kppless exploits provided ian beer ios 11 async_wake empty_list multi_path pwn20wnd also worked jay freeman original developer cydia get cydia substrate reupdated ios 11 released december 17 2018 february 22 2019 developer pwn20wnd released public update unc0ver jailbreak ios devices 12.0–12.1.2 version unc0ver uses exploits provided tihmstar sorrymybad ios 12 v1ntex v3ntex voucher_swap pwn20wnd worked jay freeman get cydia cydia substrate updated work ios 12 april 29 2019 electra team released chimera public jailbreak ios 12.0-12.1.2 included support devices including devices a12 chips major security reinforcements compared devices jailbreak uses substitute alternative cydia substrate allow tweaks run june 12 2019 developer pwn20wnd released public update unc0ver jailbreak add support ios 12.1.2-12.2 jailbreak support a8 a7 devices begin support devices added ios 12.1.2-12.2 18th august 2019 developer pwn20wnd released public update unc0ver jailbreak add support ios 12.4 added following mistake apple reintroduced vulnerabilities patched 12.3 version unc0ver used sock_puppet exploit developed ned williamson sock_port exploit developed jake james a12 devices yet supported unc0ver due incompatibility substrate lack pac bypass beyond 12.1.2
|
Computer security
|
wercker wercker docker-based continuous delivery platform helps software developers build deploy applications microservices using command-line interface developers create docker containers desktop automate build deploy processes testing desktop deploy various cloud platforms ranging heroku aws rackspace command-line interface wercker open-sourced business behind wercker also called wercker founded 2012 acquired oracle corporation 2017 wercker targets companies developers focus web applications acts middleman source-code hosting repositories like github cloud servers like amazon web services time developer makes change codebase git wercker retrieves code builds version inside container isolate tests errors notifies user either passed failed wercker integrated docker containers package application code easily moved server server build artifact docker container user take container docker hub private registry build code shipping saas platform enables developers test deploy code often push software updates incrementally ready rather bundled dumps makes easier coders practice continuous integration software engineering practice change developer makes codebase constantly tested process software ’ break goes live wercker based concept pipelines automated workflows pipelines take pieces code automatically execute series steps upon code wercker api provides programmatic access information applications builds deploys code snippets available golang node.js python service includes social networking element providing facebook-like wall team members know colleagues creates high degree transparency needed ever numerous groups work across different countries projects wercker currently available cloud services though wercker working enterprise offering allow on-premises use well hernandez van leuffen came wercker ’ underlying technology thesis project containers automatic resource provisioning university san francisco nexuslabs foundation based amsterdam mit helped wercker attract venture capital united states january 2013 wercker received seed investment a-list group investors round led shamrock ventures additional support greylock venture partners amsterdam-based micro vc vitulum ventures company executives reveal amount funding received wercker allegedly raised close 1 million wercker part 2012 startup incubator program rockstart accelerator amsterdam participated mozilla webfwd program salesforce innovation challenge also gigaom structure europe launchpad competition receiving people ’ choice judge ’ awards startup brought former co-founder openstack andy smith cto september 2014 month later wercker brought 2.4 million bringing total funding 3.2 million notion capital drove investment round along tola capital vitulum ventures shamrock ventures rockstart accelerator wercker originally focused lxc containers converted platform run ever popular docker containers late 2014 launched local development model enabling developers build deploy containerized applications entrepreneur included wercker among 9 essential tools agile product development teams july 2015 december atlassian launched wercker integration git-based bitbucket service called wercker yaml viewer january 2016 wercker announced 4.5 million series investment round led inkef capital participation notion capital bringing company ’ total funding 7.5 million first time inkef capital one largest vc funds netherlands invested developer tool wercker announced would use investment drive developer adoption expand enterprise market deepen automation capabilities flexible complex development pipelines april 17 2017 oracle announced signed definitive agreement acquire wercker
|
Distributed computing architecture
|
java api xml registries java api xml registries jaxr defines standard api java platform applications access programmatically interact various kinds metadata registries jaxr one java xml programming apis jaxr api developed java community process jsr 93 jaxr provides uniform standard java api accessing different kinds xml-based metadata registry current implementations jaxr support ebxml registry version 2.0 uddi version 2.0 registries could defined future jaxr provides api clients interact xml registries service provider interface spi registry providers plug registry implementations jaxr api insulates application code underlying registry mechanism writing jaxr based client browse populate registry code change registry changes instance uddi ebxml
|
Programming language topics
|
java community process java community process jcp established 1998 formalized mechanism allows interested parties develop standard technical specifications java technology anyone become jcp member filling form available jcp website jcp membership organizations commercial entities requires annual fees – free individuals jcp involves use java specification requests jsrs – formal documents describe proposed specifications technologies adding java platform formal public reviews jsrs take place jsr becomes final jcp executive committee votes final jsr provides reference implementation free implementation technology source code form technology compatibility kit verify api specification jsr describes jcp jsr 215 describes current version 2.7 jcp hundreds jsrs visible jsrs include jcp executive board characterized rubber stamp organization since oracle acquired sun microsystems original developer java language apache software foundation resigned seat board december 2010 oracle unwilling license technology compatibility kit apache version java source
|
Programming language topics
|
anaconda installer anaconda free open-source system installer linux distributions anaconda used red hat enterprise linux oracle linux scientific linux centos qubes os fedora sabayon linux blag linux gnu also less known discontinued distros like progeny componentized linux based debian founded ian murdock asianux foresight linux rpath linux vidalinux based gentoo anaconda offers text-mode gui mode users install wide range systems designed easily portable supports wide range hardware platforms ia-32 itanium dec alpha ibm esa/390 powerpc armv8 supports installing local storage devices like cd-rom drives harddisks well network resources via ftp http nfs installations automated use kickstart file automatically configures installation allowing users run minimal supervision starting os installation process installer checks system hardware resource requirements requirements satisfied start installation process mainly written python modules written c. graphical frontend based gtk+ 3/pygobject designed glade interface designer anaconda also custom text frontend support computers line printer like terminals ibm esa/390 mainframes
|
Operating systems
|
xenon program xenon software perform covert internet searches surveillance presently use taxing authorities least six nations investigate possibilities tax evasion various revenue producing web sites online shops gambling sites pornography sites clients selling goods on-line auction sites software uses time-controlled web spiders avoid detection likely countermeasures webmasters targeted site use may legal citizen right privacy civil liberties implicated use xenon begun netherlands 2004 dutch tax authority belastingdienst amsterdam-based data mining firm sentient machine research together tax authorities austria canada denmark united kingdom since upgraded system sweden tax authority began using xenon 2007 swedish privacy advocate expert par strom stating 2007 anticipated use xenon swedish tax authority skatteverket would legal also stated use would pose dangers citizen privacy rights—as current use time similar spidering software developed internally swedish government canadian internet law expert michael geist expressed similar privacy concerns
|
Web technology
|
e-carrier e-carrier member series carrier systems developed digital transmission many simultaneous telephone calls time-division multiplexing european conference postal telecommunications administrations cept originally standardized e-carrier system revised improved earlier american t-carrier technology adopted international telecommunication union telecommunication standardization sector itu-t widely adopted almost countries outside us canada japan e-carrier deployments steadily replaced ethernet telecommunication networks transitions towards ip e1 link operates two separate sets wires usually unshielded twisted pair balanced cable using coaxial unbalanced cable nominal 3 volt peak signal encoded pulses using method avoiding long periods without polarity changes line data rate 2.048 mbit/s full duplex i.e 2.048 mbit/s downstream 2.048 mbit/s upstream split 32 timeslots allocated 8 bits turn thus timeslot sends receives 8-bit pcm sample usually encoded according a-law algorithm 8,000 times per second 8 × 8,000 × 32 2,048,000 ideal voice telephone calls voice sampled data rate reconstructed end timeslots numbered 0 31 e1 frame defines cyclical set 32 time slots 8 bits time slot 0 devoted transmission management time slot 16 signaling rest assigned originally voice/data transport main characteristics 2-mbit/s frame described following one timeslot ts0 reserved framing purposes alternately transmits fixed pattern allows receiver lock onto start frame match channel turn standards allow full cyclic redundancy check performed across bits transmitted frame detect circuit losing bits information always used alarm signal may also transmitted using timeslot ts0 finally bits reserved national use one timeslot ts16 often reserved signalling purposes control call setup teardown according one several standard telecommunications protocols includes channel-associated signaling cas set bits used replicate opening closing circuit picking telephone receiver pulsing digits rotary phone using tone signalling passed voice circuits recent systems use common-channel signaling ccs signalling system 7 ss7 particular timeslot reserved signalling purposes signalling protocol transmitted freely chosen set timeslots different physical channel e1 channel communication consists sending consecutive frames transmitter receiver receiver must receive indication showing first interval frame begins since knows channel information time slot corresponds demultiplex correctly way bytes received slot assigned correct channel synchronization process established known frame alignment order implement frame alignment system receiver frame tell begins called frame alignment signal fas 2 mbit/s frame system fas combination seven fixed bits 0011011 transmitted first time slot frame time slot zero ts0 alignment mechanism maintained fas need transmitted every frame instead signal sent alternate frames first third fifth case ts0 used synchronization slot ts0 rest frames therefore available functions transmission alarms ts0 frames fas first bit dedicated carrying cyclic redundancy checksum crc tells us whether one bit errors specific group data received previous block eight frames known submultiframe aim system avoid loss synchronization due coincidental appearance sequence 0011011 time slot ts0 frame fas implement crc code transmission 2 mbit/s frames crc-4 multiframe built made 16 frames grouped two blocks eight frames called submultiframes crc checksum word four bits crc-4 put positions ci bits 1 frames fas next submultiframe receiving end crc submultiframe calculated locally compared crc value received next submultiframe coincide one bit errors determined found block alarm sent back transmitter indicating block received far end contains errors receiving end know first bit crc-4 word c1 reason crc-4 multiframe alignment word needed obviously receiver told multiframe begins synchronization crc-4 multiframe alignment word set combination 0011011 introduced first bits frames contain fas signal crc-4 method mainly used protect communication wrong frame alignment word also provide certain degree monitoring bit error rate ber low values around 10 method suitable cases ber around 10 block contains least one errored bit another advantage using crc bits transmitted checked unlike systems check seven bits fas ones known advance every 51 bits one fas next however crc-4 code completely infallible since probability around error may occur detected 6.25 blocks may contain errors detected code aim monitoring errors continuously check transmission quality without disturbing information traffic quality required standard taking necessary steps improve telephone traffic two way means information transmitted directions ends communication turn means two 2 mbit/s channels two directions transmission must considered crc-4 multiframe alignment word takes six first eight bits ts0 without fas two bits every second block submultiframe whose task indicate block errors far end communication mechanism follows bits called e-bits 1 default value far end communication receives 2 mbit/s frame detects erroneous block puts 0 e-bit corresponds block frame sent along return path transmitter way near end communication informed erroneous block detected ends information one crc-4 procedure e bits number frames multiframe 0 15 e-bit frame 13 refers submultiframe block received far end e-bit frame 15 refers submultiframe ii block ii bits position 2 ts0 frame contain fas called supervision bits set “ 1 ” avoid simulations fas signal bits ts0 contain fas positions 3–8 make known non-frame alignment signal nfas signal sent alternate frames frame 1 frame 3 frame 5 etc. first bit nfas bit 3 ts0 used indicate alarm occurred far end communication operating normally set 0 value 1 indicates alarm bits positions 4–8 spare bits one single application used number ways decided telecommunications carrier accordance itu-t rec g.704 bits used specific point-to-point applications establish data link based messages operations management maintenance monitoring transmission quality spare bits nfas used must set 1 international links method used transmit alarm makes use fact telephone systems transmission always two way multiplexing/demultiplexing devices known generically multiplex devices installed ends communication transmission reception frames alarm must sent transmitter device detects either power failure failure coder/decoder multiplexer following demultiplexer loss signal los loss frame alignment lof ber greater 10 remote alarm indication rai sent nfas return frames bit 3 set 1 transmitter considers serious alarm goes generating series operations depending type alarm condition detected well transmitting information generated users telephone network also necessary transmit signaling information signaling refers protocols must established exchanges users exchange information signals indicate subscriber picked telephone start dial number another subscriber calls well signals let communication link maintained e1 pcm system signaling information transmitted two different methods common channel signaling ccs method channel associated signaling cas method cases time slot ts16 basic 2 mbit/s frame used transmit signaling information ccs signaling messages several bytes transmitted 64 kbit/s channel provided ts16 frame messages providing signaling channels frame message contains information determines channel signaling signaling circuits access 64 kbit/s channel ts16 also common channels signaled different ccs systems constitute complex protocols following section way example channel associated signaling looked based e1 signal itu defined hierarchy plesiochronous signals enables signals transported rates 140 mbit/s section describes characteristics hierarchy mechanism dealing fluctuations respect nominal values rates produced consequence tolerances system case level 1 plesiochronous digital hierarchy 2 mbit/s higher levels multiplexing carried bit bit unlike multiplexing 64 kbit/s channels 2 mbit/s signal byte byte thus making impossible identify lower level frames inside higher level frame recovering tributary frames requires signal fully demultiplexed higher hierarchical levels 8,448 34,368 139,264 kbit/s etc referred 8 34 140 mbit/s simplicity obtained multiplexing four lower level frames within frame whose nominal transmission rate four times lower level see table 3 order leave room permitted variations rate justification bits well corresponding fas alarm spare bits 8 mbit/s frame structure defined itu-t rec g.742 frame divided four groups length 212 bits structure frame described itu-t rec g.751 see figure 20 previous case frame divided four groups length 384 bits structure frame described itu-t rec g.751 see figure 20 case frame divided six groups length 488 bits groups containing fas 8 34 140 mbit/s frames alarm bits spare bits also found known service bits a-bits alarm carry alarm indication remote multiplexing device certain breakdown conditions detected near-end device spare bits designed national use must set 1 digital paths cross international boundaries far synchronization concerned multiplexing plesiochronous signals completely trouble free especially comes demultiplexing circuits pcm multiplexer 30 2 channels sample output signal clock 1/32 sent coders input channels synchronized output frame however higher level multiplexers receive frames lower level multiplexers clocks whose value fluctuates around nominal frequency value within certain margins tolerance margins set itu-t recommendations hierarchical level signals thus formed almost synchronous except differences within permitted margins tolerance reason called plesiochronous order perform bit-by-bit tdm higher-order pdh multiplexer elastic memories inputs incoming bits lower level signal line tributary written since tributary signals different rates asynchronous respect prevent capacity elastic memories overflowing multiplexer reads incoming bits maximum rate permitted within range tolerances rate incoming flow tributary lines reading rate multiplexer read bits elastic memory uses stuffing bit justification bit called justification opportunity output aggregate signal task adapting signal enters multiplexer rate signal transmitted within output frame highest clock value type justification called positive justification justification bits together overhead bits make output rate higher total input signals task justification opportunity bits r-bits available extra bits used rate incoming tributaries higher nominal value within margin specified itu-t amount makes necessary case opportunity bit longer mere stuffing becomes information bit instead order device receives multiplexed signal able determine whether justification opportunity bit contains useful information i.e information tributary justification control bits j-bits included frame group control bits refers one tributaries frame set 0 associated opportunity bit carrying useful information otherwise set 1 several bits used instead one provide protection possible errors transmission examining control bits received value decided sent majority value 1 1s 0s instance assumed error bits 0 seen dispersion control bits referring tributary causes separate groups spreading j-bits control bits reduces probability errors occurring wrong decision made whether used useful data bit wrong decision made error output data also slip one bit loss repetition one bit information a-bit fas 8 34 140 mbit/s frames enables multiplexers correspond hierarchies transmit alarm indications far ends multiplexer detects alarm condition addition 140 mbit/s multiplexers also transmit alarm indication faced loss frame alignment 34-mbit/s signals received inside 140 mbit/s signals well nfas 34 mbit/s signal lost alignment bit 11 group changes 0 1 return channel pdh based e0 signal rate designed higher level multiplex set lower level signals framed e1 designed carry 30 31 e0 data channels plus 1 2 special channels levels designed carry 4 signals level necessity overhead bits justification bits account rate differences sections network subsequent level capacity greater would expected simply multiplying lower level signal rate example e2 8.448 mbit/s 8.192 mbit/s one might expect multiplying e1 rate 4 note bit interleaving used difficult demultiplex low level tributaries directly requiring equipment individually demultiplex every single level one required
|
Internet protocols
|
fog computing fog computing fog networking also known fogging architecture uses edge devices carry substantial amount computation storage communication locally routed internet backbone fog computing perceived large cloud systems big data structures making reference growing difficulties accessing information objectively results lack quality obtained content effects fog computing cloud computing big data systems may vary however common aspect limitation accurate content distribution issue tackled creation metrics attempt improve accuracy fog networking consists control plane data plane example data plane fog computing enables computing services reside edge network opposed servers data-center compared cloud computing fog computing emphasizes proximity end-users client objectives dense geographical distribution local resource pooling latency reduction backbone bandwidth savings achieve better quality service qos edge analytics/stream mining resulting superior user-experience redundancy case failure also able used assisted living scenarios fog networking supports internet things iot concept devices used humans daily basis connected examples include phones wearable health monitoring devices connected vehicle augmented reality using devices google glass spawar division us navy prototyping testing scalable secure disruption tolerant mesh network protect strategic military assets stationary mobile machine control applications running mesh nodes take internet connectivity lost use cases include internet things e.g smart drone swarms iso/iec 20248 provides method whereby data objects identified edge computing using automated identification data carriers aidc barcode and/or rfid tag read interpreted verified made available fog edge even aidc tag moved 2010 need extend cloud computing fog computing emerged order cope huge number iot devices big data volumes real-time low-latency applications november 19 2015 cisco systems arm holdings dell intel microsoft princeton university founded openfog consortium promote interests development fog computing cisco sr. managing-director helder antunes became consortium first chairman intel chief iot strategist jeff fedders became first president cloud computing fog computing provide storage applications data end-users however fog computing closer proximity end-users bigger geographical distribution ‘ cloud computing ’ practice using network remote servers hosted internet store manage process data rather local server personal computer cloud computing heavyweight dense form computing power ‘ fog computing ’ term defined flavio bonomi group cisco systems september 2010 refers extending cloud computing edge enterprise network also known edge computing fogging fog computing facilitates operation compute storage networking services end devices cloud computing data centers edge computing typically referred location services instantiated fog computing implies distribution communication computation storage resources services close devices systems control end-users fog computing medium weight intermediate level computing power rather substitute fog computing often serves complement cloud computing national institute standards technology march 2018 released definition fog computing adopting much cisco commercial terminology nist special publication 500-325 fog computing conceptual model defines fog computing horizontal physical virtual resource paradigm resides smart end-devices traditional cloud computing data center paradigm supports vertically-isolated latency-sensitive applications providing ubiquitous scalable layered federated distributed computing storage network connectivity thus fog computing distinguished distance edge per theoretical model fog computing fog computing nodes physically functionally operative edge nodes centralized cloud much terminology defined including key architectural terms like smart distinction fog computing edge computing generally agreed acceptance fog computing considered energy efficient compared cloud computing ieee adopted fog computing standards proposed openfog consortium
|
Distributed computing architecture
|
strong authentication strong authentication notion several definitions strong authentication often confused two-factor authentication generally multi-factor authentication however strong authentication necessarily multi-factor authentication soliciting multiple answers challenge questions may considered strong authentication unless process also retrieves 'something 'something would considered multi-factor authentication ffiec issued supplemental guidance subject august 2006 clarified definition true multifactor authentication requires use solutions two three categories factors using multiple solutions category ... would constitute multifactor authentication another commonly found class definitions relates cryptographic process precisely authentication based challenge response protocol type definition found handbook applied cryptography type definition necessarily relate two-factor authentication since secret key used challenge-response authentication scheme simply derived password one factor third class definitions says strong authentication form authentication verification accomplished without transmission password case example definition found fermilab documentation fourth class legal standing within european economic area strong customer authentication fast identity online fido alliance striving establish technical specifications strong authentication 250 members 150 certified products thus term strong authentication used long notion strong defined context use
|
Computer security
|
dx10 dx10 general purpose multitasking operating system designed operate texas instruments 990/10 990/10a 990/12 minicomputers using memory mapping feature dx10 versatile disk-based operating system capable supporting wide range commercial industrial applications dx10 also multiterminal system capable making several users appear exclusive control system dx10 international operating system designed meet commercial requirements united states european countries japan dx10 supported several models video display terminals vdts permit users enter view process data language dx10 required basic hardware configuration allows additional members extensive group peripherals included configuration system generation could configure dx10 support peripheral devices members 990 family devices require realtime support capability required also provide software control devices communicated dx10 easily system command interpreter sci sci designed provide simple convenient interaction user dx10 conversational format sci access complete control dx10 sci flexible mode communication sci convenient interactive communication data terminal sci accessed batch mode well dx10 capable extensive file management built-in file structures include key indexed files relative record files sequential files group file control utilities exists copying modifying files controlling file parameters dx10 offers number features provide convenient use system's capabilities
|
Operating systems
|
sportradar sportradar ag multinational corporation headquarters st. gallen switzerland collects analyzes sports data sportradar provides services bookmakers national international sports federations media companies january 2016 company 35 offices 24 countries around world including trondheim london ljubljana sportradar products includes live results statistics white-label sports content solutions brand betradar sportradar operates suite tools bookmakers including in-game pre-match odds suggestions resulting market monitoring trading services us subsidiary sportradar us sportradar official data provider us sports federations nfl nhl nascar end 2015 sportradar renewed partnership international tennis federation official data collection service partner 2016 sportradar entered partnership nba third partnership big four since 2005 company partnership german football association detect fraud match fixing system later developed launched fraud detection system addition detection fraud sportradar organizes integrity workshops together federations major league soccer serie international ice hockey federation workshops teach clubs players betting market works different forms match fixing match manipulation detected sportradar started market monitor founded 2000 trondheim norway petter fornæss tore steinkjer market monitor provided services online bookmakers based crawler technology developed part thesis norwegian university science technology market monitor together austrian german partners created product betradar.com 2001 betradar.com provides set reporting monitoring tools online betting markets carsten koerl joined market monitor major investor obtaining 51 shares 2007 sportradar ag founded owners market monitor served parent company various companies group market monitor renamed sportradar became subsidiary sportradar ag 2012 sportradar acquired slovenian development company klika later year eqt acquired minority stake investing 44 million euro company sportradar expansions continued 2013 sportradar became majority shareholder usk-based sportstat sportstat official data collection partner http //www.insidermedia.com/insider/wales/87716-sportstat-merges-swiss-business/ 2013 sportradar also advanced us market acquiring sportsdata sportradar us eqt reinvested sportradar 2014 eqt flagship fund buying shares eqt capital expansion ii 2015 sportradar obtained exclusive distribution rights nascar nfl nhl year sportradar attracted investments michael jordan mark cuban led revolution llc national football league also acquired equity sportradar us part partnership 2016 sportradar acquired core business sportman media holding including laola1.at laola1.tv later year nba announced multi-year partnership sportradar involving integrity services data distribution video streaming sportradar provides federations law enforcement agencies system detecting betting related match fixing services operated sportradar security services division headquarters london england sportradar sport integrity services began early warning system developed 2005 following hoyzer scandal use system one measures bundesliga took prevention match fixing system developed include live monitoring relaunched 2009 fraud detection system fds development fds done cooperation uefa partnership sportradar monitors suspicious matches two top leagues every uefa member nation fds since expanded partnerships sports federations including concacaf fiba esl ioc sportradar also signed agreements several law enforcement agencies notably europol australian federal police fraud detection system works comparing odds movement patterns online bookmakers expected odds movement patterns given match suspicious matches found analyzed reported relevant federation federation start investigations 2015 fraud detection system monitors 65 000 matches across 11 sports half soccer daily system receives roughly 5 billion odds adjustments around 450 different bookmakers since launch fraud detection system sportradar involved several notable match fixing cases nepal scandal 2015 austrian case including sanel kuljić 2013 australian match fixing case 2013 system indicated since 2009 2000 events likely manipulated addition sportradar provides workshops clubs federations educate consequences match fixing sportradar sports distribution covers 325 000 sport events feeds clients like google fox sports sportradar also provides data facebook sports stadium brand betradar sportradar provides bookmakers number sports betting services 2015 sportradar partnered roughly 450 bookmakers including bet365 william hill paddy power ladbrokes sportradar services also used state lotteries veikkaus svenska spel norsk tipping sportradar create odds thousands games across 40 sports odds created feeding sports data collected sportradar mathematical models in-game betting odds requires continuous recalculation outcomes using live data sportradar collects acquires licenses odds sold odds suggestions bookmakers matches bookmakers unable create odds similarly sportradar provides information bookmakers matches start finish allow money placed matches finished subset sportradar collected data goes extensive quality assurance process specialised bet clearing sportradar also provides market monitoring allows bookmakers compare odds rest market bookmakers provide odds make use service thus making odds part comparison bookmakers service allows bookmakers ensure unwanted surebet situation august 12 2019 sportradar extended relationship national football league become exclusive provider official league data sports betting operators united states internationally jurisdictions betting legal regulated sportradar also use integrity services monitor betting nfl games right distribute live audiovisual feeds nfl games sportsbooks select international markets sportradar partnered several sports federations collect distribute sports data handball-bundesliga sportradar collects distributes official data itf umpire enters data directly sportradar systems nhl sportradar ingests redistributes data coming nhl tracking system partnerships us federations nascar nhl nfl handled us subsidiary sportradar us partly order avoid conflict interest federation sportradar involvement betting industry distribution partnerships also include creating official web mobile solutions well rights stream video content partnerships one esl include using data expand sportradar betting services deal signed october 2015 sportradar provide football association malaysia platform managing federation platform federation manage things schedules leagues personnel players referees tool also provides means collecting live data distributed teams partners visualised various web solutions
|
Web technology
|
exec system call computing exec functionality operating system runs executable file context already existing process replacing previous executable act also referred overlay especially important unix-like systems although operating systems implement well since new process created original process identifier pid change machine code data heap stack process replaced new program exec call supported many programming languages including compilable languages scripting languages os command interpreters built-in command replaces shell process specified program interfaces exec implementations vary depending programming language may accessible via one functions depending operating system may represented one actual system calls reason exec sometimes described collection functions standard names functions c see exec linux kernel one corresponding system call named execve whereas aforementioned functions user-space wrappers around higher-level languages usually provide one call named posix standard declares exec functions header file c language functions declared dos see os/2 microsoft windows implementations provide functions named leading underscore e.g _execl base exec execute followed one letters calls new process image inherits current environment variables file descriptor open exec call made remain open new process image unless marked codice_2 codice_3 opened codice_4 latter introduced posix.1-2001 aspect used specify standard streams stdin stdout stderr new program successful overlay destroys previous memory address space process memory areas shared reclaimed operating system consequently data passed new program otherwise saved become lost successful exec replaces current process image return anything program made call processes exit status exec-ing termination process continues exist exec function return calling program error occurred case return value −1 errno set one following values linux kernel may destroy memory map old process start constructing loading new executable discover new executable ca n't loaded example fields executable internal tables contain invalid values case process killed fatal signal sigsegv ideally kernel would fail codice_5 return error indication old executable would significantly complex slower dos multitasking operating system replacing previous executable image great merit due harsh primary memory limitations lack virtual memory api used overlaying programs dos effects similar ones posix systems ms-dos exec functions always load new program memory maximum allocation program executable file header set default value 0xffff exehdr utility used change maximum allocation field program however done program invoked one exec functions program might behave differently program invoked directly operating-system command line one spawn functions see many unix shells also offer builtin command replaces shell process specified program wrapper scripts often use command run program either directly interpreter virtual machine setting environment variables configuration using exec resources used shell program need stay use program started command also perform redirection shells passing arguments means use command redirection without making actual overlay traditional unix system functionality create new process running new executable program one step explains importance exec unix programming systems may use spawn main tool running executables result equivalent fork-exec sequence unix-like systems posix supports posix_spawn routines optional extension usually implemented using vfork os/360 successors include system call xctl transfer control performs similar function exec except type 4 svc usage rare common use link attach invoke load module without terminating current load module particular tso invokes commands attach sharing memory
|
Computer architecture
|
authenticated received chain authenticated received chain arc email authentication system designed allow intermediate mail server like mailing list forwarding service sign email original authentication results allows receiving service validate email email spf dkim records rendered invalid intermediate server processing arc defined rfc 8617 published july 2019 experimental dmarc allows sender domain indicate emails protected spf and/or dkim tells receiving service neither authentication methods passes reject message however strict dmarc policy may block legitimate emails sent mailing list forwarder spf check fail due unapproved sender dkim signature invalidated message modified adding subject tag footer arc helps solve problem giving intermediate servers way sign original message validation results even spf dkim validation fail receiving service choose validate arc arc indicates original message passed spf dkim checks modifications made intermediaries trusted receiving service receiving service may choose accept email arc defines three new mail headers sign modification intermediate server performs following steps validate arc recipient performs following steps
|
Computer security
|
firmex firmex cloud-based virtual data room service provider headquartered toronto ontario canada virtual data rooms facilitate secure document sharing across corporate firewalls used highly confidential complex transactions seen corporate finance procurement well regulatory compliance governance processes 2004 davies ward phillips vineberg toronto-based international business law firm contracted version 5.1 develop davies deal room online virtual data room software designed facilitate legal transactions transactions project commercialized version 5.1 2006 firmex inc. 2007 2008 firmex raised total 4.4 million angel investors end 2009 company licensed 500 customers running 2,500 transactions year 2011 firmex reached customer milestone 1,000 2012 company workforce grew 25 percent 2014 firmex named 13 deloitte technology fast 50 2015 firmex deloitte fast 500 winner https //www2.deloitte.com/content/dam/deloitte/us/documents/technology-media-telecommunications/technology-fast-500-winners-ranking-list.pdf 2016 novacap montreal-based private equity fund acquired majority interest firmex http //www.novacap.ca/en/news/tmt/novacap-invests-in-firmex-to-accelerate-growth/ firmex customers started 12000 virtual data rooms 2018 firmex expanded european operations opening office london england https //www.firmex.com/blog/news/firmex-opens-new-emea-headquarters-london-uk/ 2019 vertu capital toronto-based private equity fund bdc capital firmex management acquired firmex https //www.pehub.com/2019/02/vertu-and-bdc-to-acquire-firmex-from-novacap/
|
Distributed computing architecture
|
timit timit corpus phonemically lexically transcribed speech american english speakers different sexes dialects transcribed element delineated time timit designed acoustic-phonetic knowledge automatic speech recognition systems commissioned darpa corpus design joint effort massachusetts institute technology sri international texas instruments ti speech recorded ti transcribed mit verified prepared publishing national institute standards technology nist also telephone bandwidth version called ntimit network timit timit ntimit freely available — either membership linguistic data consortium monetary payment required access dataset
|
Computational linguistics
|
sandbox computer security computer security sandbox security mechanism separating running programs usually effort mitigate system failures software vulnerabilities spreading often used execute untested untrusted programs code possibly unverified untrusted third parties suppliers users websites without risking harm host machine operating system sandbox typically provides tightly controlled set resources guest programs run scratch space disk memory network access ability inspect host system read input devices usually disallowed heavily restricted sense providing highly controlled environment sandboxes may seen specific example virtualization sandboxing frequently used test unverified programs may contain virus malicious code without allowing software harm host device sandbox implemented executing software restricted operating system environment thus controlling resources example file descriptors memory file system space etc process may use examples sandbox implementations include following use cases sandboxes include following
|
Operating systems
|
blagger video game blagger platform game created antony crowther commodore 64 released alligata 1983 bbc micro port released year acorn electron amstrad cpc amsoft msx 1984 commodore 16 plus/4 1985 countries game released name gangster gameplay similar manic miner also released 1983 sequel son blagger released 1984 third final title blagger goes hollywood released 1985 game divided series single-screen levels goal player screen manipulate blagger burglar collect scattered keys reach safe keys must collected safe opened set amount time blagger walk either left right jump left right jumping action fixed pattern altered initiated gameplay reduces learning best order collect keys correct timing movements jumping platforms solid decay blagger walked platforms serve move blagger particular direction blagger die touches cacti one moving enemy obstacles level falls certain distance moving enemies vary level level include cars aliens mad hatters giant mouths movement enemies fixed pattern repeatedly travelling one point another back bbc electron versions feature floating rg hazards r.g initials programmer versions r.s goodley
|
Computer architecture
|
gsoap gsoap c c++ software development toolkit soap/xml web services generic xml data bindings gsoap tools generate efficient source code xml serialization type c/c++ data zero-copy overhead gsoap toolkit started research project florida state university professor robert van engelen 1999 project introduced new methods highly-efficient xml parsing pull parsing serialization c/c++ data directly xml later also soap project succeeded defining type-safe data bindings xml schema types wide variety c/c++ data types toolkit uses automatic programming simplify development invocation web services using efficient auto-generated xml serializers send receive c/c++ data directly domain-specific compiler-based tool generates source code efficiently converts native c/c++ data structures xml back toolkit developed support soap web services messaging protocol introduced around time therefore name gsoap generic xml soap use approach scientific data exchange development maintenance software took place ownership genivia inc includes addition new wsdl xml schema processing capabilities well addition many ws-* web services protocol capabilities ws-security optimizations xml-rpc messaging support json data format plugin modules integrate gsoap apache iis web servers third-party plugins grid services gsoap toolkit written portable c/c++ uses form bootstrapping generating code implement converter translate wsdl/xsd specifications c/c++ source code wsdl/xsd meta-data bindings gsoap software licensed gplv2 open source license commercial-use source code licenses gsoap software widely used industrial projects mission-critical infrastructures example web service operation c retrieving lodging rate hotel given number guests declared annotated form last parameter function always service return value denoted void one-way operations struct/class bundle multiple service return parameters function int return value used error diagnostics service invocation c using auto-generated soap_call_ns__get_rate function executed follows facilitate web services implementations legacy c c++ systems prefix qualification identifier names c/c++ omitted replaced colon notation example ns get_rate rather ns__get_rate punctuation removed auto-generated source code used project builds service invocation c++ using auto-generated proxy class executed follows using proxy default endpoint url soap action values using annotations identifier naming conventions i.e qualification prefix ns__ function ns__get_rate declaring properties ns namespace using //gsoap directives example binding established web service operations auto-generated web services description language wsdl document declares request message response message get-rate operation porttype interface soap binding ns__get_rate function follows request responses messages operation refer xml elements defined types section wsdl follows likewise client server c/c++ source code auto-generated set wsdls xml schemas services must completed defining appropriate service operations example auto-generated c++ service class wsdl must completed defining get_rate method follows restrictions type operation parameters marshaled xml web service messaging except certain type declaration conventions annotations followed establish data binding establish xml data binding c/c++ data types gsoap uses three basic forms source code annotation directives identifier naming conventions punctuation fully annotated structure declaration c hierarchical employee record may appear following annotations conventions used gsoap tools convert c/c++ data types to/from xml schema data types since c support namespaces struct/class member names namespace-qualified c++ use identifier naming conventions gsoap allow binding structure members xml schema complextype auto-generated follows furthermore unions struct/class annotated special selector field union member selection mapped to/from schema choice particles stl containers mapped to/from sequence particles enumerations mapped to/from xml schema simpletype enumerations standard c/c++ primitive types mapped to/from xsd types conversion xsd schema c/c++ data types actual mapping configurable gsoap type mapping file instance example hierarchical employee structure serialized xml tree default example soap encoding style enabled xml serialization gsoap respects co-referenced objects cyclic data structures per soap encoding rules resulting xml id-ref edges auto-generated xml data binding includes read write operations to/from file string stream example ns__employee_record object read write operations read employee record xml file parsed xml internally validated data bindings constraints application data sent received to/from rest xml service xml data binding provides rest xml api calls example given ns__employee_record xml data binding previous section following get put post operations auto-generated post functions called together first post_send transmit xml data endpoint url followed post_recv accept response data may different type received xml internally validated data bindings constraints
|
Web technology
|
message forgery cryptography message forgery sending message deceive recipient real sender common example sending spam prank e-mail originated address one really used
|
Computer security
|
loginradius loginradius inc. cloud based saas customer identity access management platform based vancouver british columbia canada established 2012 loginradius started 2012 two friends deepak gupta rakesh soni social login widget interview soni said duo started company recognizing hassles registration websites negative effects conversion rates according company loginradius platform 200 pre-built integrations different customer relationship management ad platform email marketing tools platform involved collection customer data traditional email based registration social profile data acquired customer data secured cloud based storage loginradius also provides single customer view customer data aggregated one record organizations using loginradius platform integrate marketing tools
|
Distributed computing architecture
|
nivio nivio company marketing desktop virtualization services allow customer use computer application software without personal computer sachin dev duggal saurabh pradeep dhoot founded nivio 2004 two founders met students imperial college london 2000 initial funding came two executives deutsche bank duggal worked time claimed idea came 20 minutes presentation headquarters switzerland development center gurgaon nvivo announced test first online windows xp-based desktop service 2007 early reviews mixed noting high data-rate continuous connections needed good response times existing products companies citrix systems advanced micro devices announced investment undisclosed value august 2007 several patents related technology assigned smx inet global services sa nivio subsidiary december 2008 nivio named technology pioneer world economic forum affordable computing access nivio announced nivio companion june 2009 bharti airtel limited india internet service provider companion low-cost product including keyboard mouse set-top-box style terminal monthly service charge user gets internet access microsoft office 2007 functionality 10 gbytes storage one motivation given rampant software piracy india indian media reported company young founders since 2007 january 2010 duggal promoted cloud computing world economic forum davos february 2010 nivio announced operations australia hosted nec polaris data centre springfield queensland july 2010 company estimated us 5 million revenues profitable earlier nivio companion product called test november 2010 duggal dhoot claimed goal education 2012 nivio reported announce devices called cloudbook cloudpc provide access services although us patent trademark office shows cloudbook trademark application date december 2009 nholdings business nivio product everex marketed cloudbook around 2008 registration nholdings sa gives location mont-sur-lausanne formerly using name smx inet global services sa microsoft remote desktop services technology allowed nivio officially licensed service provider license agreement use remote desktop protocol contrasts services onlive desktop trucloud licensing terms raised questions press approach also contrasted official support microsoft office ipad videocon aec partners invested us 21 million company february 2012 co-founder dhoot nephew videocon chairman venugopal dhoot offices opened palo alto california silicon valley well new delhi april 2012 nivio announced application use microsoft office files stored google drive product received mixed reviews since products still by-invitation beta testing stages judged easy use kate russell bbc reported company products august 2012 near end 2012 duggal stepped operational roles nivio frank houghton became chief operating officer company announced would provide services businesses stuart collingwood president europe middle east africa 2014 company appears gone web site shut twitter feed dormant since 2013
|
Distributed computing architecture
|
arch hurd arch hurd operating system based arch linux uses gnu hurd kernel instead linux kernel arch hurd project founded arch linux forum thread january 2010 weeks many contributions progressed point could boot virtual machine aims provide arch-like user environment bsd-style init scripts i686-optimised packages use pacman package manager rolling-release kiss set hurd stable enough use despite small development team much progress made since founding booting real hardware packaging everything basic web server production unofficial graphical livecd june 2011 arch hurd announced successful integration device driver environment dde — framework linux drivers hurd improves network hardware support distribution makes nearly usable
|
Operating systems
|
oasis organization organization advancement structured information standards oasis global nonprofit consortium works development convergence adoption open standards security internet things energy content technologies emergency management areas oasis founded name sgml open 1993 began trade association sgml tool vendors cooperatively promote adoption standard generalized markup language sgml mainly educational activities though amount technical activity also pursued including update cals table model specification specifications fragment interchange entity management 1998 movement high tech industry xml sgml open changed emphasis sgml xml changed name oasis open inclusive xml reflect expanded scope technical work standards focus consortium activities also moved promoting adoption xml getting lots attention developing technical specifications july 2000 new technical committee process approved adoption process manner technical committees created operated progressed work regularized adoption process five technical committees 2004 nearly 70 1999 oasis approached un/cefact committee united nations dealing standards business jointly develop new set specifications electronic business joint initiative called ebxml first met november 1999 chartered three-year period final meeting original charter vienna un/cefact oasis agreed divide remaining work two organizations coordinate completion work coordinating committee 2004 oasis submitted completed ebxml specifications iso tc154 approved iso 15000 consortium headquarters burlington massachusetts shared companies september 4 2014 consortium moved 25 corporate drive suite 103 35 corporate dr suite 150 still loop route following standards development oasis technical committees adhesion consortium requires fees paid must renewed annually depending membership category adherents want access among adherents members american bar association collabora dell eclecticiq general motors ibm iso/iec kde e.v. microsoft novell oracle redhat document foundation universities government agencies individuals employees less-known companies like many bodies producing open standards e.g ecma oasis added reasonable non-discriminatory licensing rand clause policy february 2005 amendment required participants disclose intent apply software patents technologies consideration standard contrary w3c requires participants offer royalty-free licenses anyone using resulting standard oasis offers similar royalty free limited terms mode along royalty free rand terms mode rand reasonable non-discriminatory mode committees compared w3c oasis less restrictive regarding obligation companies grant royalty-free license patents controversy rapidly arisen licensing added silently allows publication standards could require licensing fee payments patent holders situation could effectively eliminate possibility free/open source implementations standards contributors could initially offer royalty-free use patent later imposing per-unit fees standard accepted april 11 2005 new york times reported ibm committed free patents oasis group larry rosen software law expert leader reaction rose oasis quietly included rand clause policy welcomed initiative supposed oasis continue using policy companies involved would follow history proved wrong rand policy still removed commercial companies published free statement towards oasis patrick gannon president ceo oasis 2001 2008 minimized risk company could take advantage standard request royalties established option nobody uses harm sam hiser former marketing lead defunct openoffice.org explained patents towards open standard counterproductive inappropriate also argued ibm microsoft shifting standardization efforts w3c oasis way leverage probably patents portfolio future hiser also attributed rand change oasis policy microsoft rand term could indeed theoretically allow company involved leverage patent future amendment probably added way attract companies consortium encourage contributions potential participants big actors like microsoft could indeed applied pressure made sine-qua-non condition access consortium possibly jeopardize/boycott standard clause present doug mahugh — working microsoft promoter office open xml microsoft document format competing oasis iso/iec 26300 i.e odf v1.0 senior product manager specializing office client interoperability — claimed many countries expressed frustration pace oasis responses defect reports submitted iso/iec 26300 inability sc 34 members participate maintenance odf however rob weir co-chair oasis odf technical committee noted time odf tc received zero defect reports iso/iec national body japan added submitter original japanese defect report murata mokoto satisfied preparation errata also self-published blog post blaming microsoft involving people improve modify accuracy odf openxml wikipedia articles trying make odf sound risky adopt
|
Web technology
|
program transformation program transformation operation takes computer program generates another program many cases transformed program required semantically equivalent original relative particular formal semantics fewer cases transformations result programs semantically differ original predictable ways transformations performed manually often practical use program transformation system applies specifications required transformations program transformations may specified automated procedures modify compiler data structures e.g abstract syntax trees representing program text may specified conveniently using patterns templates representing parameterized source code fragments practical requirement source code transformation systems able effectively process programs written programming language usually requires integration full front-end programming language interest including source code parsing building internal program representations code structures meaning program symbols useful static analyses regeneration valid source code transformed program representations problem building integrating adequate front ends conventional languages java c++ php etc may equal difficulty building program transformation system complexity languages widely useful transformation system must able handle many target programming languages must provide means specifying front ends generalisation semantic equivalence notion program refinement one program refinement another terminates initial states original program terminates state guaranteed terminate possible final state original program words refinement program defined deterministic original program two programs refinements programs equivalent
|
Programming language topics
|
bill gosper ralph william gosper jr. born april 26 1943 known bill gosper american mathematician programmer along richard greenblatt may considered founded hacker community holds place pride lisp community high school gosper interested model rockets one friends injured rocketry accident contracted fatal brain infection gosper enrolled mit 1961 received bachelor degree mathematics mit 1965 despite becoming disaffected mathematics department anti-computer attitude second year mit gosper took programming course john mccarthy became affiliated mit ai lab contributions computational mathematics include hakmem mit maclisp system made major contributions macsyma project mac computer algebra system gosper later worked symbolics macsyma inc. commercial versions macsyma 1974 moved stanford university lectured worked donald knuth since time worked consulted xerox parc symbolics wolfram research lawrence livermore laboratory macsyma inc became intensely interested game life shortly john horton conway proposed conway conjectured existence infinitely growing patterns offered reward example gosper first find pattern glider gun prize gosper also originator hashlife algorithm speed computation life patterns many orders magnitude gosper created numerous packing problem puzzles twubblesome twelve gosper first person realize possibilities symbolic computation computer mathematics research tool whereas computer methods previously limited purely numerical methods particular research resulted work continued fraction representations real numbers gosper algorithm finding closed form hypergeometric identities 1985 gosper briefly held world record computing digits pi 17 million digits see chronology computation π
|
Programming language topics
|
vmware vmfs vmware vmfs virtual machine file system vmware inc. clustered file system used company flagship server virtualization suite vsphere developed store virtual machine disk images including snapshots multiple servers read/write filesystem simultaneously individual virtual machine files locked vmfs volumes logically grown non-destructively increased size spanning multiple vmfs volumes together five plus one vsan versions vmfs corresponding esx/esxi server product releases java open source vmfs driver enables read-only access files folders partitions formatted virtual machine file system vmfs developed maintained fluid operations ag allows features like offloaded backups virtual machines hosted vmware esxi hosts vmfsv3 based fluidops code vmfs-tools evolved add vmfs features supports read vmfs mounts standard linux vfs fuse framework developed christophe fillot mike hommey available source code download glandium.org vmfs-tools page debian vmfs-tools ubuntu vmfs-tools packages
|
Computer file systems
|
link quality report link quality report lqr protocol part point-to-point protocol ppp allows two computers connect lqr allows peers either end ppp link assess state quality ppp link lqr transmits counts packets sent received rejected errors report signal noise attenuation order produce link quality reports ppp peer implement link quality monitoring link quality monitoring consists maintaining number counters counters include use lqrs negotiated ppp link first established peer wants receive lqr packets signals sending ppp configuration option following data lqr one packet containing counters well addition receiving peer add following fields lqr packet arrives numbers come mib database ppp receive logic maintains saved use next lqr packet peer sends number ppp implementations cause errors lqr generation implementations negotiate correctly lqrs fail send leads local peer determining ppp link failed led users using less capable lcp echos detect whether link still functioning lcp echos provide information lqr could provide
|
Internet protocols
|
scielo scielo scientific electronic library online bibliographic database digital library cooperative electronic publishing model open access journals scielo created meet scientific communication needs developing countries provides efficient way increase visibility access scientific literature originally established brazil 1997 today 16 countries scielo network journal collections argentina bolivia brazil chile colombia costa rica cuba ecuador mexico paraguay peru portugal south africa spain uruguay venezuela scielo initially supported são paulo research foundation fapesp brazilian national council scientific technological development cnpq along latin american caribbean center health sciences information bireme scielo provides portal integrates provides access scielo network sites users search across scielo collections limit single country collection browse subject area publisher journal title october 2015 database contained different countries universally accessible free open access full-text format scielo project stated aims envisage development common methodology preparation storage dissemination evaluation scientific literature electronic format journals published special software suite implements scientific electronic virtual library accessed via several mechanisms including table titles alphabetic subject list subject author indexes search engine project launch timeline 2013 latin american scielo project completed 15 years free publishing open access long emphasized access scholarly materials however open access also mean access means producing visible recognized journals issue particularly important developing emergent countries benefits challenges publishing scientific journals emerging countries articles sent scielo publishers xml html+sgml using variety article dtds sgml dtd used 2013 scielo started offer journal article tag suite jats dtd standard xml deposites using markup xml macro proprietary desktop application microsoft office word docx scielo portals received jats-articles converted via xslt html sgml+html pack articles use html content general handmade pdf-to-html conversion process may reveal errors reported back publisher correction graphics also converted standard formats sizes original converted forms archived converted form moved relational database along associated files graphics multimedia associated data many publishers also provide pdfs articles made available without change bibliographic citations sgml xml parsed automatically linked associated articles scielo resources publishers web sites unresolvable references journals particular articles yet available one sources tracked database automatically come live resources become available in-house indexing system provides search capability july 2015 jeffrey beall american librarian posted article blog referring two largest latin american open access databases scielo redalyc favelas derogatory portuguese term slum beall stated many north american scholars never even heard meta-publishers journals aggregate content largely hidden neighborhood remote unfamiliar among responses motion passed brazilian forum public health journals editors associação brasileira de saúde coletiva abrasco brazilian public health association motion takes exception beall characterization draws attention underlying ethnocentric prejudice corrects factual inaccuracies counterpoint beall neocolonial point view motion draws attention work vessuri guedon cetto emphasizing value initiatives scielo redalyc also targeted beall development science latin america globally fact latin america using oa publishing model far greater extent region world… also sense public mission remains strong among latin american universities… current initiatives demonstrate region contributes global knowledge exchange positioning research literature public good
|
Databases
|
dynamo programming language dynamo dynamic models historically important simulation language accompanying graphical notation developed within system dynamics analytical framework originally industrial dynamics soon extended applications including population resource studies urban planning dynamo initially developed direction jay wright forrester late 1950s dr. phyllis fox alexander l. pugh iii grace duren others m.i.t computation center dynamo used system dynamics simulations global resource-depletion reported club rome limits growth since fallen disuse 1958 forrester unwittingly instigated dynamo development asked mit staff programmer compute needed solutions equations harvard business review paper writing industrial dynamics programmer richard bennett chose implement system simple simulation industrial management problems lots equations took coded equations symbolic input computed solutions simple became proof-of-concept dynamo rather specialist programmer hard-code special-purpose solver general purpose programming language users could specify system equations special simulation language get simulation output one program execution dynamo designed emphasize following among ways dynamo standard time featured units checking numerical types relatively clear error messages earliest versions written assembly language ibm 704 ibm 709 ibm 7090 dynamo ii written aed-0 extended version algol 60 dynamo ii/f 1971 generated portable fortran code dynamo ii/f dynamo iii improved system portability written fortran originally designed batch processing mainframe computers made available minicomputers late 1970s became available micro-dynamo personal computers early 1980s language went several revisions dynamo ii dynamo iv 1983 apart indirectly felt public impact environmental issues raised controversy limits growth dynamo influential history discrete-event simulation even though essentially package continuous simulation specified difference equations said opened opportunities computer modelling even users relatively low mathematical sophistication hand also criticized weak precisely mathematical sophistication required relying euler integration
|
Programming language topics
|
art deception art deception book kevin mitnick covers art social engineering part book composed real stories examples social engineering combined hacking nearly examples fictional quite plausible expose ease skilled social engineer subvert many rules people take granted examples book also giving example tell tricked/conned victims scam prevent real life business book ends mitnick strategy business plans prevent scams book
|
Computer security
|
software fault tolerance software fault tolerance ability computer software continue normal operation despite presence system hardware faults fault-tolerant software ability satisfy requirements despite failures thing constant change certainly true software systems almost phenomenon software change way software fault tolerance methods designed overcome execution errors modifying variable values create acceptable program state need control software fault one rising challenges facing software industries today fault tolerance must key consideration early stage software development exist different mechanisms software fault tolerance among computer applications make call using application programming interface api access shared resources like keyboard mouse screen disk drive network printer fail two ways blocked call request services operating system halts computer program results available example tcp call blocks response becomes available remote server occurs every time perform action web browser intensive calculations cause lengthy delays effect blocked api call two methods used handle blocking threading allows separate sequence execution api call block prevent overall application stalling waiting resource benefit none information state api call lost activities take place threaded languages include following timers allow blocked call interrupted periodic timer allows programmer emulate treading interrupts typically destroy information related state blocked api call intensive calculation programmer must keep track information separately un-threaded languages include following corrupted state occur timers avoided following fault induced signals posix compliant systems signals originate api calls operating system applications signal handler code becomes fault causes premature application termination handler function performed on-demand application receives signal called exception handling termination signal signal handled signals directed handler function handler functions come two broad varieties initialized handler functions paired signal software starts causes handler function startup corresponding signal arrives technique used timers emulate threading in-line handler functions associated call using specialized syntax familiar following used c++ java hardware fault tolerance software requires following backup maintains information event hardware must replaced done one two ways backup requires information-restore strategy make backup information available replacement system restore process usually time-consuming information unavailable restore process complete redundancy relies replicating information one computer computing device recovery delay brief achieved using continuous backup live system remains inactive needed synchronized backup also achieved replicating information created multiple identical systems eliminate recovery delay
|
Computer security
|
canadian trusted computer product evaluation criteria canadian trusted computer product evaluation criteria ctcpec computer security standard published 1993 communications security establishment provide evaluation criterion products combination tcsec also called orange book european itsec approaches ctcpec led creation common criteria standard canadian system security centre part communications security establishment founded 1988 establish canadian computer security standard
|
Computer security
|
revolution software platform revolution software development environment/multimedia authoring software tradition hypercard based metacard engine primary focus providing relatively accessible development tool set scripting language enable creation software programs run across multiple platforms little code modifications integrated development environment ide included revolution built partly models created bill atkinson original hypercard team apple subsequently followed many software development products microsoft visual basic revolution includes english language-like scripting language called transcript full programming language superset hypercard scripting language hypertalk higher-grade versions see versions allow applications compiled run one platform including macintosh classic mac os 9 mac os x windows unix-like systems including linux also import hypercard stacks require little modification unless use external functions generally work revolution revolution designed environment non-programmers feel ease programmers feel uncomfortable getting used non-traditional programming syntax like programming language development environment opinions degree aims achieved vary greatly revolution 2 starter kit version available freeware imposed restrictions user allowing scripts longer ten lines compiled however since discontinued longer available download dreamcard version intended home users/hobbyists applications called stacks built using require either dreamcard player full copy revolution run dreamcard include revolution compiler studio version powerful useful creating professional binary applications enterprise version probably expensive casual users compared similar products borland delphi kylix priced competitively one wishes develop programs non-microsoft platforms cross-platform deployment revolution one small handful commercially supported options revolution derived metacard engine metacard stacks 100 compatible revolution however way around necessarily true hypercard stacks run externals run macs supercard stacks must run converter upgraded revolution/metacard format revolution runs mac classic mac os x windows 9x/nt/2000/xp following unix variants standalone applications written revolution run well windows 3.1 limitations march 2005 dreamcard player runs windows mac os classic x linux linux user gnome/xfce/gtk+ theme used gtk+ installed otherwise motif look used mac appearance manager used available otherwise platinum look used windows xp theme standard widgets used users preview motif platinum windows appearance platform many companies groups use revolution engine mainly used freelance programmers make small widgets libraries one example used exclusively christa mcauliffe space education center
|
Programming language topics
|
vlan hopping vlan hopping computer security exploit method attacking networked resources virtual lan vlan basic concept behind vlan hopping attacks attacking host vlan gain access traffic vlans would normally accessible two primary methods vlan hopping switch spoofing double tagging attack vectors mitigated proper switch port configuration switch spoofing attack attacking host imitates trunking switch speaking tagging trunking protocols e.g multiple vlan registration protocol ieee 802.1q dynamic trunking protocol used maintaining vlan traffic multiple vlans accessible attacking host switch spoofing exploited interfaces set negotiate trunk prevent attack cisco ios use one following methods 1 ensure ports set negotiate trunks automatically disabling dtp 2 ensure ports meant trunks explicitly configured access ports double tagging attack attacker connected 802.1q-enabled port prepends two vlan tags frame transmits frame externally tagged vlan id attacker port really member forwarded without first tag native vlan trunk interface second tag visible second switch frame encounters second vlan tag indicates frame destined target host second switch frame sent target host though originated target vlan effectively bypassing network mechanisms logically isolate vlans one another however possible replies forwarded attacking host unidirectional flow double tagging exploited switch ports configured use native vlans trunk ports configured native vlan n't apply vlan tag sending frames allows attacker fake vlan tag read next switch double tagging mitigated following actions incl ios example example double tagging attack consider secure web server vlan called vlan2 hosts vlan2 allowed access web server hosts outside vlan2 blocked layer 3 filters attacking host separate vlan called vlan1 native creates specially formed packet attack web server places header tagging packet belonging vlan2 header tagging packet belonging vlan1 packet sent switch sees default vlan1 header removes forwards packet next switch sees vlan2 header puts packet vlan2 packet thus arrives target server though sent another host vlan2 ignoring layer 3 filtering might place
|
Computer security
|
druid video game druid action-adventure game developed electralyte software published firebird 1986 atari 8-bit family commodore 64 also ported amstrad cpc zx spectrum game ported nippon dexter msx japan-only 1988 another japanese port druid entitled made famicom disk system jaleco 1988 game followed inspired arcade game gauntlet druid fantasy-themed action-adventure game player plays part hasrinaxx druid trying rid world dark mage acamantor army demons hasrinaxx must travel several levels first level normal landscape ones underground one deeper previous level infested various enemies ghosts giant insects witches four demon princes hasrinaxx shoot enemies three different weapons water fire electricity come finite supply equally effective enemies using chaos spell destroy enemies player vicinity well replenishing energy four demon princes defeated chaos spell common weapons ineffective hasrinaxx also summon golem help turn invisible brief period commodore 64 version second player take control golem using joystick port 2
|
Computer architecture
|
richard greenblatt programmer richard d. greenblatt born december 25 1944 american computer programmer along bill gosper may considered founded hacker community holds place distinction communities programming language lisp massachusetts institute technology mit artificial intelligence laboratory greenblatt born portland oregon december 25 1944 family moved philadelphia pennsylvania child later moved columbia missouri mother sister parents divorced greenblatt enrolled mit fall 1962 around second term undergraduate student found way mit famous tech model railroad club time peter samson written program fortran ibm 709 series machines automate tedious business writing intricate timetables railroad club vast model train layout greenblatt felt compelled implement fortran compiler pdp-1 lacked one computer time available debug compiler even type computer years later elements compiler combined ideas fellow tmrc member steven piner author early pdp-4 fortran compiler working digital equipment corporation typed showed signs life however perceived need fortran compiler evaporated compiler pursued experiences tmrc especially influence alan kotok worked dec junior partner design team pdp-6 computer led greenblatt ai lab proceeded become hacker hacker noted programming acumen described steven levy acknowledged gerald jay sussman harold abelson said fortunate apprentice programmers feet bill gosper richard greenblatt indeed spent much time programming programmed data processor pdp machines failed mit first-term junior take job firm charles adams associates ai lab hired 6 months later 1979 tom knight main designers mit lisp machine founded lisp machines inc. later renamed gigamos systems according vision ideal hacker-friendly computer company opposed commercial ideals symbolics main implementor maclisp pdp-6 wrote mac hack first computer program play tournament-level chess first compete human chess tournament ai skeptic hubert dreyfus famously made claim computers would able play high-quality chess beaten program marking start respectable computer chess performances 1977 unbeaten chess champion bobby fischer played three games cambridge massachusetts greenblatt computer program fischer greenblatt along tom knight stewart nelson co-wrote incompatible timesharing system highly influential time-sharing operating system pdp-6 pdp-10 used mit
|
Programming language topics
|
binkp binkp protocol transferring fidonet wwivnet mail reliable connections typically used deliver mail internet instead point-to-point connections modems historically fidonet traffic transferred mainly serial rs-232 modem connections might error correction layer dial-up-oriented protocols transferring fidonet traffic like emsi zmodem implement error-recovery members fidonet started use tcp/ip transfer fidonet traffic error-recovery overhead became unnecessary assuming connection reliable makes possible eliminate error-checking unnecessary synchronization steps achieving ease implementation improved performance major advantage binkp vs emsi zmodem achieved connections large delays low bandwidth iana internet assigned numbers authority registered port number 24554 binkp used tcp/ip connections
|
Internet protocols
|
av-comparatives av-comparatives austrian independent organization tests assesses antivirus software regularly releasing charts reports freely available public media antivirus vendors meet various requirements regarding trustworthiness reliability order take part tests av-comparatives issues relevant awards based antivirus software comprehensive performance according multiple testing criteria also supported university innsbruck academic bodies around world well austrian federal government regional government tirol av-comparatives real world protection test test environment closely approximates well antivirus product protect real-world users test results released monthly march june august november two detailed overall result reports released june december real world protection test framework recognized “ standortagentur tirol ” 2012 cluster award innovation computer science 2018 av-comparatives started large scale enterprise security software test series consisting real-world test false alarm test malware protection test performance test well review av-comparatives provided undroid apk analyzer free service website users since may 2013 designed android smartphone users provides static analysis android apps users upload android application package apk receive quick online analysis containing file hashes graphical danger level additional information
|
Computer security
|
google assistant google assistant artificial intelligence-powered virtual assistant developed google primarily available mobile smart home devices unlike company previous virtual assistant google google assistant engage two-way conversations assistant initially debuted may 2016 part google messaging app allo voice-activated speaker google home period exclusivity pixel pixel xl smartphones began deployed android devices february 2017 including third-party smartphones android wear wear os released standalone app ios operating system may 2017 alongside announcement software development kit april 2017 assistant extended support large variety devices including cars third party smart home appliances functionality assistant also enhanced third-party developers 2017 google assistant installed 400 million devices users primarily interact google assistant natural voice though keyboard input also supported nature manner google assistant able search internet schedule events alarms adjust hardware settings user device show information user google account google also announced assistant able identify objects gather visual information device camera support purchasing products sending money well identifying songs ces 2018 first assistant-powered smart displays smart speakers video screens announced first one released july 2018 google assistant unveiled google developer conference may 18 2016 part unveiling google home smart speaker new messaging app allo google ceo sundar pichai explained assistant designed conversational two-way experience ambient experience extends across devices later month google assigned google doodle leader ryan germick hired former pixar animator emma coats develop little personality system-level integration outside allo app google home google assistant initially exclusive pixel pixel xl smartphones february 2017 google announced begun enable access assistant android smartphones running android marshmallow nougat beginning select english-speaking markets android tablets receive assistant part rollout assistant also integrated android wear 2.0 included future versions android tv android auto october 2017 google pixelbook became first laptop include google assistant google assistant later came google pixel buds december 2017 google announced assistant would released phones running android lollipop update google play services well tablets running 6.0 marshmallow 7.0 nougat february 2019 google reportedly began testing ads google assistant results may 15 2017 android police reported google assistant would coming ios operating system separate app information confirmed two days later google developer conference january 2018 consumer electronics show first assistant-powered smart displays released smart displays shown event lenovo sony jbl lg devices support google duo video calls youtube videos google maps directions google calendar agenda viewing smart camera footage addition services work google home devices devices based android things google-developed software google unveiled smart display google home hub october 2018 utilizes different system platform december 2016 google launched actions google developer platform google assistant actions google allows 3rd party developers build apps google assistant march 2017 google added new tools developing actions google support creation games google assistant originally limited google home smart speaker actions google made available android ios devices may 2017 time google also introduced app directory overview compatible products services incentivize developers build actions google announced competition first place tickets google 2018 developer conference 10,000 walk-through google campus second place third place received 7,500 5,000 respectively google home april 2017 software development kit sdk released allowing third-party developers build hardware run google assistant integrated raspberry pi cars audi volvo smart home appliances including fridges washers ovens companies including irobot lg general electric d-link google updated sdk december 2017 add several features google home smart speakers google assistant smartphone apps previously supported features include may 2 2018 google announced new program blog focuses investing future google assistant early-stage startups focus build environment developers could build richer experiences users includes startups broaden assistant features building new hardware devices simply differentiating different industries google assistant nature manner google search internet schedule events alarms adjust hardware settings user device show information user google account unlike google however assistant engage two-way conversation using google natural language processing algorithm search results presented card format users tap open page february 2017 google announced users google home would able shop entirely voice products google express shopping service products available whole foods market costco walgreens petsmart bed bath beyond launch retailers added following months new partnerships formed google assistant maintain shopping list previously done within notetaking service google keep feature moved google express google home app april 2017 resulting severe loss functionality may 2017 google announced assistant would support keyboard typed input visual responses support identifying objects gather visual information device camera support purchasing products sending money use keyboard users see history queries made google assistant edit delete previous inputs assistant warns deleting however due use previous inputs generate better answers future november 2017 became possible identify songs currently playing asking assistant.. google assistant allows users activate modify vocal shortcut commands order perform actions device android ipad/iphone configuring hub home automation feature speech recognition available english among languages july 2018 google home version assistant gained support multiple actions triggered single vocal shortcut command annual i/o developers conference may 8 2018 google seo announced addition six new voice options google assistant one john legend made possible wavenet voice synthesizer developed deepmind significantly reduced amount audio samples voice actor required produce creating voice model august 2018 google added bilingual capabilities google assistant existing supported languages devices recent reports say may support multilingual support setting third default language android phone default option google assistant n't support two common features speech recognition transcribed texts like punctuation spelling however beta feature speech-to-text enables en-us language users ask detect insert punctuation transcription results speech-to-text recognize commas question marks periods transcription requests april 2019 popular audio games assistant crystal ball lucky trivia biggest voice change software history voice assistant able add expression games instance crystal ball game voice would speak slow soft intro answer revealed make game excitable lucky trivia game voice would become excitable like game show host british accent voice crystal ball voice would say word 'probably downwards slide like sure games used text speech voice makes voice robotic may 2019 however turned bug speech api caused games lose studio quality voices audio games fixed may 20th 2019 may 2018 google revealed duplex extension google assistant allows carry natural conversations mimicking human voice manner dissimilar robocalling assistant autonomously complete tasks calling hair salon book appointment scheduling restaurant reservation calling businesses verify holiday store hours duplex complete tasks fully autonomously able recognize situations unable complete signal human operator finish task duplex created speak natural voice language incorporating speech disfluencies filler words like hmm uh using common phrases mhm gotcha along human-like intonation response latency duplex currently development limited release late 2018 google pixel users limited release pixel phone users atlanta new york phoenix san francisco able use duplex make restaurant reservations announcement concerns made ethical societal questions artificial intelligence technology duplex raises instance human operators may notice speaking digital robot conversing duplex critics view unethical deceitful concerns privacy also identified conversations duplex recorded order virtual assistant analyze respond privacy advocates also raised concerns millions vocal samples gathered consumers fed back algorithms virtual assistants making forms ai smarter use though features individualize user experience critics unsure long term implications giving company unprecedented access human patterns preferences crucial next phase artificial intelligence could potentially lead ai outsmarting creators transparency referred key part experience technology revealed google later clarified statement saying designing feature disclosure built-in 'll make sure system appropriately identified google added certain jurisdictions assistant would inform end phone call recorded pc world mark hachman gave favorable review google assistant saying step cortana siri digital trends called smarter google ever july 2019 belgian public broadcaster vrt nws published article revealing 3rd party contractors paid transcribe audio clips collected google assistant listened sensitive information users sensitive data collected google home devices android phones included names addresses private conversations business calls bedroom conversations 1000 recordings analysed 153 recorded without ‘ okay google ’ command google officially acknowledged 0.2 recordings listened language experts improve google services august 1 2019 germany ’ hamburg commissioner data protection freedom information initiated administrative procedure prohibit google carrying corresponding evaluations employees third parties period three months provisionally protect rights privacy data subjects time citing gdpr google spokesperson stated google paused “ language reviews ” european countries investigated recent media leaks google assistant new feature google assistant supported languages
|
Operating systems
|
group control system group control system gcs operating system made ibm meant run guest vm gcs integral component discontinued vm/sp since vm/sp 4 vm/xa sp vm/esa current z/vm ibm system product offerings gcs purpose provide environment run specific os/mvs-based applications networking middleware vm end gcs provides limited simulation os/mvs apis cms usual vm guest already os simulation extensive enough run applications vtam specifically gcs provides os multitasking support order able spread load several virtual machines gcs also implements notion group group member virtual machine interact one another implement gcs uses several techniques gcs designed multi-purpose user operating system cms example allow file editing examples programs designed run gcs
|
Operating systems
|
jim jagielski jim jagielski born march 11 1961 american software engineer specializes web cloud open source technologies jagielski graduated johns hopkins university 1983 bes electrical/computer engineering hired nasa goddard space flight center immediately graduation 1994 jagielski founded jagunet access services web host isp served cto zend technologies cto covalent technologies chief architect springsource/vmware office cto red hat inc. consulting software engineer sr. director capital one tech fellows program currently open source chef consensys speaker various conferences seminars apachecon forrester gigaworld o'reilly open source convention written numerous topics editor apache section slashdot best known cofounder member director apache software foundation asf core developer several asf projects including apache http server apache portable runtime apache tomcat first recognition internet editor a/ux faq system administrator jagubox primary repository third-party software apple a/ux operating system addition involvement asf jagielski involved open-source projects jagielski one founding members apache software foundation member original eight-member apache group jagielski served director asf board incorporation 1999 2018 making longest serving director foundation history served eight years executive vice president secretary three years chairman jagielski served several years president asf jagielski original chair apache incubator project still involved one original co-mentors geronimo project also mentors several incubator podlings jagielski active developer many open source projects asf otherwise development ncsa httpd web server started apache early-to-mid 1995 making likely longest active contributor within asf 2005 jagielski asked serve advisory board open source software institute open source software institute ossi non-profit 501 c 6 organization corporate government academic representatives mission promote development implementation open-source software solutions within u.s. federal state municipal government agencies academic entities 2010 jagielski appointed board directors codeplex foundation later renamed outercurve foundation well director jagielski serves president outercurve 2011 jagielski appointed board directors open source initiative resigned september 2013 based long involvement foss community jagielski one recipients o'reilly open source awards oscon 2012 2012 jagielski appointed new council member marsec-xl foundation 2015 jagielski awarded european commission/open innovation strategy policy group luminary award creating open engagement platforms global efforts promoting open source innovation process jagielski contributed sendmail xntpd bind php perl freebsd among projects
|
Operating systems
|
system programming language system programming language programming language used system programming languages designed writing system software usually requires different development approaches compared application software system software computer software designed operate control computer hardware provide platform running application software system software includes software categories motherboard firmware components firmware chipset peripheral controllers sometimes cpu microcode architectures provide rich complex isa interpreted simple general purpose hardware circuits bios/uefi second stage boot loaders operating systems comprising essential always running services api exposed system libraries user applications interfaces kernel address space obviously kernel utilities system administration device drivers loaders dynamic linkers contrast application languages system programming languages typically offer more-direct access physical hardware machine archetypical system programming language sense bcpl system programming languages often lack built-in input/output i/o facilities system-software project usually develops i/o mechanisms builds top basic monitor i/o screen management facilities distinction languages used system programming application programming became blurred time widespread popularity pl/i c pascal earliest system software written assembly language primarily alternative also reasons including efficiency object code compilation time ease debugging application languages fortran used system programming although usually still required routines written assembly language mid-level languages much syntax facilities higher level language also provide direct access language well providing assembly language machine features earliest espol burroughs mainframes 1960 followed niklaus wirth pl360 initially written burroughs system cross compiler general syntax algol 60 whose statements directly manipulated cpu registers memory languages category include mol-360 pl/s example typical pl360 statement codice_1 signifying registers 8 7 and'ed together result shifted left 8 bits result or'ed contents register 6 final result placed register 9 pl360 semantic level assembly language another kind system programming language operates higher semantic level specific extensions designed make language suitable system programming early example kind language lrltran extended fortran features character bit manipulation pointers directly addressed jump tables subsequently languages c developed combination features sufficient write system software compiler could developed generated efficient object programs modest hardware language generally omits features implemented efficiently adds small number machine-dependent features needed access specific hardware capabilities inline assembly code c asm statement often used purpose although many languages developed c c++ ones survived system programming language spl also name specific language hp 3000 computer series used operating system hp multi-programming executive parts system software
|
Programming language topics
|
radsec radsec protocol transporting radius datagrams tcp tls radius protocol widely deployed authentication authorization protocol supplementary radius accounting specification also provides accounting mechanisms thus delivering full aaa protocol solution however radius experiencing two major shortcomings time passes since initial design dependency unreliable transport protocol udp lack security large parts packet payload specifically latter radius security based md5 algorithm proven insecure main focus radsec provide means secure communication radius/tcp peers transport layer important use radsec lies roaming environments radius packets need transferred different administrative domains untrusted potentially hostile networks example world-wide roaming environment uses radsec secure communication eduroam radius extensions working group internet engineering task force ietf specified radsec rfc 6614
|
Internet protocols
|
reboot computing rebooting process running computer system restarted either intentionally unintentionally reboots either cold alternatively known hard power system physically turned back causing initial boot machine warm alternatively known soft system restarts without need interrupt power term restart used refer reboot operating system closes programs finalizes pending input output operations initiating soft reboot early electronic computers like ibm 1401 operating system little internal memory input often stack punch cards computer initiated pressing start button performed single command read card first card instructed machine read cards eventually loaded user program process likened old saying picking bootstraps referring horseman lifts ground pulling straps boots set initiating punch cards called bootstrap cards thus cold start called booting computer computer crashed rebooted boot reference carried subsequent types computers see bootstrapping technical sources describe two contrasting forms reboot known cold reboot also cold boot hard reboot hard boot warm reboot also soft reboot soft boot although definition forms vary slightly sources according jones landes tittel 2002 cooper 2002 tulloch 2002 soper 2004 ibm pc compatible platform cold boot boot process computer starts powerless state except tulloch 2002 also mention cold boot system performs power-on self-test post addition power switch cooper 2002 soper 2004 also state reset button present may commence cold reboot jones landes tittel 2002 contradicts assertion states reset button may commence either cold warm reboot depending system microsoft support article 102228 also confers although reset button designed perform cold reboot may disconnect power motherboard – state correspond cold boot definition given according jones landes tittel 2002 operating system third-party software initiate cold boot restart command windows 9x initiates cold reboot unless shift key held finding definition warm boot however challenge aforementioned sources indicate warm boot initiated pressing ctrl alt delete key combination except tulloch 2002 mention warm reboot perform post jones landes tittel 2002 specifies warm reboot occur bios must recipient key combination microsoft support article 102228 takes technical approach defines warm boot result invoking int 19h bios interrupt call ctrl alt delete key combination one way achieving according grimes 2001 malware may prevent subvert warm boot intercepting ctrl alt delete key combination prevent reaching bios windows nt family operating systems also reserves key combination use soper 2004 asserts windows restart command initiates warm boot thus contradicting jones landes tittel 2002 believe action performs cold boot linux family operating systems supports alternative warm boot linux kernel optional support kexec system call transfers execution new kernel skips hardware firmware reset entire process occurs independently system firmware kernel executed linux kernel outside domain ibm compatible pcs types boot may disambiguous according sue loh windows ce base team windows ce devices support three types boots warm cold clean warm boot discards program memory cold boot additionally discards storage memory also known object store clean boot erases forms memory storage device however since areas exist windows ce devices users concerned two forms reboot one resets volatile memory one wipes device clean restores factory settings example windows mobile 5.0 device former cold boot latter clean boot hard reboot means system shut orderly manner skipping file system synchronisation activities would occur orderly shutdown achieved either applying reset cycling power issuing command unix-like systems triggering kernel panic term restart used microsoft windows linux family operating systems denote operating system-assisted reboot restart operating system ensures pending i/o operations gracefully ended commencing reboot users may deliberately initiate reboot rationale action may include means performing deliberate reboot also vary may include unexpected loss power reason including power outage power supply failure depletion battery mobile device forces system user perform cold boot power restored bioses option automatically boot system power failure uninterruptible power supply ups backup battery redundant power supply prevent circumstances random reboot non-technical term referring unintended often undesired reboot following system crash whose root cause may immediately evident user crashes may occur due multitude software hardware problems triple faults generally symptomatic error ring 0 trapped error handler operating system hardware-triggered non-maskable interrupt systems may configured reboot automatically power failure fatal system error kernel panic method done varies depending whether reboot handled software must handled firmware hardware level operating systems windows nt family windows nt 3.1 windows 7 option modify behavior error handler computer immediately restarts rather displaying blue screen death bsod error message option enabled default editions introduction advanced power management allowed operating systems greater control hardware power management features advanced configuration power interface acpi newer operating systems able manage different power states thereby sleep and/or hibernate hibernation also involves turning system subsequently back operating system start scratch thereby differentiating process rebooting reboot may simulated software running operating system example sysinternals bluescreen utility used pranking modes bsod xscreensaver hack entertainment albeit possibly concerning first glance malware may also simulate reboot thereby deceive computer user nefarious purpose microsoft app-v sequencing tool captures file system operations installer order create virtualized software package users part sequencing process detect installer requires reboot interrupt triggered reboot instead simulate required reboot restarting services loading/unloading libraries windows 8 10 enable default hibernation-like fast startup a.k.a fast boot cause problems including confusion users accustomed turning computers cold reboot
|
Operating systems
|
4x4 off-road racing 4x4 off-road racing video game racing genre released 1988 epyx developed ogdan micro design inc four maps consist mud ice desert mountains compute called game enjoyable drive spanish magazine microhobby valued game following scores originality 50 graphics 50 motion 60 sound 50 difficulty 70 addiction 40
|
Computer architecture
|
cyber-security regulation cybersecurity regulation comprises directives safeguard information technology computer systems purpose forcing companies organizations protect systems information cyberattacks like viruses worms trojan horses phishing denial service dos attacks unauthorized access stealing intellectual property confidential information control system attacks numerous measures available prevent cyberattacks cybersecurity measures include firewalls anti-virus software intrusion detection prevention systems encryption login passwords attempts improve cybersecurity regulation collaborative efforts government private sector encourage voluntary improvements cybersecurity industry regulators including banking regulators taken notice risk cybersecurity either begun planned begin include cybersecurity aspect regulatory examinations 2011 dod released guidance called department defense strategy operating cyberspace articulated five goals treat cyberspace operational domain employ new defensive concepts protect dod networks systems partner agencies private sector pursuit whole-of-government cybersecurity strategy work international allies support collective cybersecurity support development cyber workforce capable rapid technological innovation march 2011 gao report identified protecting federal government information systems nation cyber critical infrastructure governmentwide high-risk area noting federal information security designated high-risk area since 1997 2003 systems protecting critical infrastructure called cyber critical infrastructure protection cyber cip also included november 2013 dod put forward new cybersecurity rule 78 fed reg 69373 imposed certain requirements contractors compliance certain nist standards mandatory reporting cybersecurity incidents dod flow-down clause applies requirements subcontractors june 2013 congressional report found 50 statutes relevant cybersecurity compliance federal information security management act 2002 fisma one key statutes governing federal cybersecurity regulations federal cybersecurity regulations ones exist focus specific industries three main cybersecurity regulations 1996 health insurance portability accountability act hipaa 1999 gramm-leach-bliley act 2002 homeland security act included federal information security management act fisma three regulations mandate healthcare organizations financial institutions federal agencies protect systems information example fisma applies every government agency requires development implementation mandatory policies principles standards guidelines information security however regulations address numerous computer related industries internet service providers isps software companies furthermore regulations specify cybersecurity measures must implemented require reasonable level security vague language regulations leaves much room interpretation bruce schneier founder cupertino counterpane internet security argues companies make sufficient investments cybersecurity unless government forces also states successful cyberattacks government systems still occur despite government efforts suggested data quality act already provides office management budget statutory authority implement critical infrastructure protection regulations administrative procedure act rulemaking process idea fully vetted would require additional legal analysis rulemaking could begin state governments attempted improve cybersecurity increasing public visibility firms weak security 2003 california passed notice security breach act requires company maintains personal information california citizens security breach must disclose details event personal information includes name social security number driver license number credit card number financial information several states followed california example passed similar security breach notification regulations security breach notification regulations punish firms cybersecurity failures giving freedom choose secure systems also regulation creates incentive companies voluntarily invest cybersecurity avoid potential loss reputation resulting economic loss come successful cyber attack 2004 california state legislature passed california assembly bill 1950 also applies businesses maintain personal information california residents regulation dictates businesses maintain reasonable level security required security practices also extend business partners regulation improvement federal standard expands number firms required maintain acceptable standard cybersecurity however like federal legislation requires reasonable level cybersecurity leaves much room interpretation case law established us congress proposed numerous bills expand upon cybersecurity regulation consumer data security notification act amends gramm-leach-bliley act require disclosure security breaches financial institutions congressmen also proposed expanding gramm-leach-bliley industries touch consumer financial information including firm accepts payment credit card congress proposed cybersecurity regulations similar california notice security breach act companies maintain personal information information protection security act requires data brokers ensure data accuracy confidentiality authenticate track users detect prevent unauthorized activity mitigate potential harm individuals addition requiring companies improve cybersecurity congress also considering bills criminalize cyberattacks securely protect cyber trespass act spy act bill type focused phishing spyware bill passed may 23 2005 us house representatives died us senate bill makes unlawful unauthorized usage computer take control modify setting collect induce owner disclose personally identifiable information install unsolicited software tamper security anti-spyware anti-virus software may 12 2011 us barack obama proposed package cybersecurity legislative reforms improve security us persons federal government critical infrastructure year public debate congress hearings followed resulting house representative passing information sharing bill senate developing compromise bill seeking balance national security privacy business interests july 2012 cybersecurity act 2012 proposed senators joseph lieberman susan collins bill would required creating voluntary best practice standards protection key infrastructure cyber attacks businesses would encouraged adopt incentives liability protection bill put vote senate failed pass obama voiced support act wall street journal op-ed also received support officials military national security including john o. brennan chief counterterrorism adviser white house according washington post experts said failure pass act may leave united states vulnerable widespread hacking serious cyberattack act opposed republican senators like john mccain concerned act would introduce regulations would effective could burden businesses senate vote republican senator kay bailey hutchison stated opposition bill partisan issue take right approach cybersecurity.the senate vote strictly along partisan lines six democrats voted five republicans voted critics bill included us chamber commerce advocacy groups like american civil liberties union electronic frontier foundation cybersecurity expert jody westby heritage foundation argued although government must act cybersecurity bill flawed approach represented intrusive federal role february 2013 obama proposed executive order improving critical infrastructure cybersecurity represents latest iteration policy considered law addressed congress yet seeks improve existing public-private partnerships enhancing timeliness information flow dhs critical infrastructure companies directs federal agencies share cyber threat intelligence warnings private sector entity identified target also tasks dhs improving process expedite security clearance processes applicable public private sector entities enable federal government share information appropriate sensitive classified levels directs development framework reduce cyber risks incorporating current industry best practices voluntary standards lastly tasks federal agencies involved incorporating privacy civil liberties protections line fair information practice principles january 2015 obama announced new cybersecurity legislative proposal proposal made effort prepare us expanding number cyber crimes proposal obama outlined three main efforts work towards secure cyberspace us first main effort emphasized importance enabling cybersecurity information sharing enabling proposal encouraged information sharing government private sector would allow government know main cyber threats private firms facing would allow government provide liability protection firms shared information furthermore would give government better idea us needs protected another main effort emphasized proposal modernize law enforcement authorities make equipped properly deal cyber crimes giving tools need order would also update classifications cyber crimes consequences one way would done would making crime overseas selling financial information another goal effort place cyber crimes prosecutable last major effort legislative proposal require businesses report data breaching consumers personal information sacrificed requiring companies consumers aware danger identity theft february 2016 obama developed cybersecurity national security action plan cnap plan made create long-term actions strategies effort protect us cyber threats focus plan inform public growing threat cyber crimes improve cybersecurity protections protects personal information americans inform americans control digital security one highlights plan include creating commission enhancing national cybersecurity goal create commission consists diverse group thinkers perspectives contribute make recommendations create stronger cybersecurity public private sector second highlight plan change government new government make secure put place third highlight plan give americans knowledge secure online accounts avoid theft personal information multi-factor authentication fourth highlight plan invest 35 money invested 2016 cybersecurity addition regulation federal government tried improve cybersecurity allocating resources research collaborating private sector write standards 2003 president national strategy secure cyberspace made department homeland security dhs responsible security recommendations researching national solutions plan calls cooperative efforts government industry create emergency response system cyber-attacks reduce nation vulnerability threats 2004 us congress allocated 4.7 billion toward cybersecurity achieving many goals stated president national strategy secure cyberspace industry security experts state president national strategy secure cyberspace good first step insufficient bruce schneier stated national strategy secure cyberspace n't secured anything yet however president national strategy clearly states purpose provide framework owners computer systems improve security rather government taking solving problem however companies participate collaborative efforts outlined strategy required adopt discovered security solutions united states us congress trying make information transparent cyber security act 2012 would created voluntary standards protecting vital infrastructure failed pass senate february 2013 white house issued executive order titled improving critical infrastructure cybersecurity allows executive branch share information threats companies individuals april 2013 house representatives passed cyber intelligence sharing protection act cispa calls protecting lawsuits aimed companies disclose breach information obama administration said might veto bill light hacking website indian space agency commercial arm 2015 antrix corporation government digital india programme cyberlaw expert advocate supreme court india pavan duggal stated dedicated cyber security legislation key requirement india sufficient merely put cyber security part act see cyber security sectoral perspective also national perspective cybersecurity standards great prominence today technology driven businesses maximize profits corporations leverage technology running operations internet since large number risks entail internetwork operations operations must protected comprehensive extensive regulations existing cybersecurity regulations cover different aspects business operations often vary region country business operates differences country society infrastructure values one overarching cyber security standard optimal decreasing risks us standards provide basis operations european union created tailored regulation businesses operating specifically within eu also light brexit important consider uk chosen adhere security regulations three major regulations within eu include enisa nis directive eu gdpr european union agency network information security enisa governing agency originally set regulation ec 460/2004 european parliament council 10 march 2004 purpose raising network information security nis internetwork operations eu enisa currently runs regulation eu 526/2013 replaced original regulation 2013 enisa works actively member states eu provide range services focus operations three factors enisa made management board relies support executive director permanent stakeholders group operations however run heads various departments enisa released various publications cover major issues cybersecurity enisa past current initiatives include eu cloud strategy open standards information communications technology cyber security strategy eu cyber security coordination group enisa also works collaboration existing international standard organizations like iso itu july 6 2016 european parliament set policy directive security network information systems nis directive directive went effect august 2016 member states european union given 21 months incorporate directive regulations national laws aim nis directive create overall higher level cybersecurity eu directive significantly affects digital service providers dsps operators essential services oess operators essential services include organizations whose operations would greatly affected case security breach engage critical societal economic activities dsps oes held accountable reporting major security incidents computer security incident response teams csirt dsps held stringent regulations operators essential services dsps set eu still operate eu still face regulations even dsps oes outsource maintenance information systems third parties nis directive still holds accountable security incidents member states eu required create nis directive strategy includes csirts addition national competent authorities ncas single points contact spocs resources given responsibility handling cybersecurity breaches way minimizes impact addition member states eu encouraged share cyber security information security requirements include technical measures manage risks cybersecurity breaches preventative manner dsp oes must provide information allows depth assessment information systems security policies significant incidents must notified csirts significant cybersecurity incidents determined number users affected security breach well longevity incident geographical reach incident eu general data protection regulation gdpr set place 14 april 2016 current date enforcement set 25 may 2018 gdpr aims bring single standard data protection among member states eu changes include redefining geographical borders applies entities operate eu deal data resident eu regardless data processed eu citizen data processed entity subject gdpr fines also much stringent gdpr total €20 million euros 4 entity annual turnover whichever higher addition like previous regulations data breaches effect rights freedoms individuals residing eu must disclosed within 72 hours overarching board eu data protection board edp charge oversight set gdpr consent plays major role gdpr companies hold data regards eu citizens must also offer right back sharing data easily consented sharing data addition citizens also restrict processing data stored choose allow companies store data process creates clear differentiation unlike previous regulations gdpr also restricts transfer citizen data outside eu third party without citizen prior consent proposed eprivacy regulation also planned applicable 25 may 2018 experts agree cybersecurity improvements necessary disagreement whether solution government regulation private-sector innovation many government officials cybersecurity experts believe private sector failed solve cybersecurity problem regulation needed richard clarke states industry responds threaten regulation industry respond threat follow believes software companies must forced produce secure programs bruce schneier also supports regulation encourages software companies write secure code economic incentives us representative rick boucher d–va proposes improving cybersecurity making software companies liable security flaws code addition improving software security clarke believes certain industries utilities isps require regulation hand many private-sector executives lobbyists believe regulation restrict ability improve cybersecurity harris miller lobbyist president information technology association america believes regulation inhibits innovation rick white former corporate attorney president ceo lobby group technet also opposes regulation states private-sector must continue able innovate adapt response new attack methods cyber space toward end commend president bush congress exercising regulatory restraint another reason many private-sector executives oppose regulation costly involves government oversight private enterprise firms concerned regulation reducing profits regulation limiting flexibility solve cybersecurity problem efficiently
|
Computer security
|
syskey sam lock tool better known syskey name executable file discontinued component windows nt encrypts security account manager sam database using 128-bit rc4 encryption key first introduced windows nt 4.0 sp3 removed windows 10 windows server 2016 due use cryptography considered insecure modern standards use part scams form ransomware microsoft officially recommended use bitlocker disk encryption alternative first introduced windows nt 4.0 sp3 syskey intended protect offline password cracking attacks preventing possessor unauthorized copy sam file extracting useful information syskey optionally configured require user enter key boot startup password load key onto removable storage media e.g. floppy disk usb flash drive october 2 2018 microsoft removed syskey.exe future versions windows microsoft recommends use bitlocker similar technologies instead syskey.exe utility december 1999 security team bindview found security hole syskey indicated certain form offline cryptanalytic attack possible making brute force attack appear possible microsoft later issued fix problem dubbed syskey bug bug affected windows nt 4.0 pre-rc3 versions windows 2000 syskey commonly abused tech support scammers lock victims computers order coerce paying ransom
|
Operating systems
|
windows ultimate extras windows ultimate extras optional features offered microsoft users ultimate edition windows vista accessible via windows update ultimate extras replaced market role microsoft plus product sold prior consumer releases microsoft windows according microsoft barry goffe company goal ultimate extras delight customers purchased ultimate edition windows vista expensive retail edition operating system windows ultimate extras discontinued windows 7 operating system also removes installed extras upgrade windows vista ultimate microsoft released total nine ultimate extras users windows vista ultimate bitlocker drive preparation tool utility secure online key backup utility among first ultimate extras made available released coincide general retail availability windows vista bitlocker drive preparation tool prepares hard drive encrypted bitlocker whereas secure online key backup enabled users create off-site backup bitlocker recovery password encrypting file system recovery certificates digital locker part windows marketplace digital distribution platform secure online key backup rendered inoperable digital locker shut august 2009 unlike previous versions windows windows vista language-independent language architecture separates language resources user interface binary code operating system support installing additional languages included enterprise ultimate editions windows vista ultimate edition functionality made available windows update ultimate extras microsoft stated 16 languages made available january 30 2007 company released remaining language packs october 23 2007 total 35 language packs additional 36th language pack version available windows vista supports traditional chinese characters hong kong encoding character set microsoft tinker puzzle game players must navigate robot mazes obstacles total 60 levels included players create levels level editor hold 'em poker card game released january 29 2007 fundamentally similar texas hold 'em hold 'em allows users play five computer players three levels difficulty also allows users customize aspects game appearance game relies directx produce hardware-accelerated 3d animations effects optimal performance hold 'em requires computer windows experience index rating 2.0 higher according paul thurrott hold 'em originally intended bundled alongside premium games— chess titans mahjong titans inkball —included default home premium ultimate editions windows vista instead made ultimate extra gambling themes total three sound schemes windows vista released ultimate extras glass ultimate extras pearl microsoft tinker first two made available april 22 2008 latter made available day microsoft tinker glass pearl sound schemes similar default sound scheme included windows vista also developed accordance design language principles windows aero graphical user interface windows dreamscene utility enables mpeg wmv videos displayed desktop backgrounds dreamscene requires windows aero graphical user interface enabled order function feature relies desktop window manager display videos desktop additional extras also proposed released including podcast creation application game performance optimization utility custom themes exclusive access online content services windows movie maker effects transitions templates windows dvd maker digital publications group shot photo manipulation application developed microsoft research shown bill gates consumer electronics show 2007 although considered ultimate extras company ultimate extras team also released two wallpapers users windows vista ultimate titled start strands wallpapers based design windows vista ultimate retail packaging made available three different display resolutions reaction windows ultimate extras mixed microsoft praised creating value proposition users purchased expensive edition windows vista company criticized delays delivery updates perceived lack quality delivered updates lack transparency regarding development early concerns features would live users expectations company announced several ultimate extras january 2007 fraction released five months later months without official update since january microsoft released apology delays stating intended ship remaining features end summer 2007 delays consecutive updates months silence led speculation development team within company responsible features quietly disbanded microsoft announced intentions release remaining ultimate extras released apology delays paul thurrott stated company dropped ball features ed bott wrote ultimate extras probably biggest mistake microsoft made vista company would downplay ultimate edition windows 7 result bott would later list among decade worth windows mistakes microsoft also criticized changing description ultimate extras within operating system offerings slated made available initially described cutting-edge programs innovative services unique publications description features within control panel applet later modified windows vista service pack 1 modest interpreted attempt made company avoid fulfilling prior expectations emil protalinski ars technica wrote ultimate edition windows vista would looked fine without joke 'ultimate extras features supposed provide incentive consumers purchase edition give critics something point laugh second part review windows 7 peter bright ars technica wrote value proposition ultimate extras nothing short piss-poor bright would later criticize microsoft decision release internet explorer 10 windows vista would go state still bad ultimate extras farce
|
Operating systems
|
enterprise interoperability framework enterprise interoperability framework used guideline collecting structuring knowledge/solution enterprise interoperability framework defines domain sub-domains interoperability research development order identify set pieces knowledge solving enterprise interoperability problems removing barriers interoperability existing works interoperability carried define interoperability framework reference models particular lisi reference model european interoperability framework eif ideas interoperability framework athena interoperability framework e-health interoperability framework existing approaches constitute basis enterprise interoperability framework necessity elaborate enterprise interoperability framework discussed existing interoperability frameworks explicitly address barriers interoperability basic assumption research aimed structuring interoperability knowledge respect ability remove various barriers enterprise interoperability framework three basic dimensions framework three basic dimensions shown enterprise interoperability framework allows enterprise interoperability framework aims structuring concepts defining research domain capturing knowledge also helping industries solve interoperability problems carrying interoperability project involving two particular enterprises interoperability concerns interoperability barriers two enterprises identified first mapped enterprise interoperability framework using framework existing interoperability degree characterised targeted interoperability degree defined objective meet knowledge/solutions associated barriers concerns searched framework solutions found proposed users possible adaptation and/or combination solutions remove identified barriers required interoperability established
|
Computer architecture
|
linux technology center ibm linux technology center ltc organization focused development linux kernel related open-source software projects 1999 ibm created ltc combine software developers interested linux open-source software single organization much ltc early effort focused making server platforms linux friendly ltc collaborated linux community make linux run optimally processor architectures x86 mainframe powerpc power isa recent years focus ltc expanded include several open source initiatives developers ltc contribute various open-source projects ltc worldwide team main locations australia brazil china germany india israel united states
|
Operating systems
|
medical data breach medical data breach data breach health information could include either personal health information individual electronic health record medical billing information health insurance united states rate breaches increased time 176 million records breached end 2017 february 2015 npr report claimed organized crime networks ways selling health data black market 2015 beazley group staffperson estimated medical records could sell black market -50 crime primary cause medical data breaches theft data loss hacking unauthorized account access ways medical data breaches happen among reported breaches medical information united states networked information systems accounted largest number records breached united states health insurance portability accountability act health information technology economic clinical health act require companies report data breaches affected individuals federal government
|
Computer security
|
boehm garbage collector computer science boehm–demers–weiser garbage collector often simply known boehm gc conservative garbage collector c c++ boehm gc free software distributed permissive free software licence similar x11 license developer describes operation collector follows boehm gc also run leak detection mode memory management still done manually boehm gc check done properly way programmer find memory leaks double deallocations boehm gc also distributed c string handling library called cords similar ropes c++ strings trees small arrays never change instead using reference counting proper deallocation relies garbage collection free objects cords good handling large texts modifications middle slicing concatenating keeping history changes undo/redo functionality garbage collector works unmodified c programs simply replacing malloc gc_malloc calls replacing realloc gc_realloc calls removing free calls code piece shows one use boehm instead traditional malloc free c. boehm gc used many projects implemented c c++ like inkscape well runtime environments number languages including crystal gnu compiler java runtime environment portable.net project embeddable common lisp gnu guile mono implementation microsoft .net platform also using precise compacting gc since version 2.8 libgc-d binding libgc programming language used primarily mci supports numerous operating systems including many unix variants macos microsoft windows provides number advanced features including incremental collection parallel collection variety finalizer semantics
|
Operating systems
|
yamaha cx5m yamaha cx5m msx-system compatible computer expands upon normal features expected systems built-in eight-voice fm synthesizer module introduced 1984 yamaha corporation fm synth stereo audio outputs input purpose-built four-octave keyboard pair midi input/output ports could used normal midi second revision cx5m management data yamaha dx7 first model cx5m built msx standard included slots inserting programmed cartridges extended machine capability accepting range games office applications yamaha produced range cartridges including programmer yamaha dx range fm keyboards real-time sequencer two voice editor music composer allowed user program bank 48 sounds cx5 built synthesizer sequence eight channels music controlling built-in module external instruments via midi step-time using musical-stave input screen three versions cx5m released first contained fm module sfg-01 could receive external midi note information required proprietary keyboard used midi port output send data yamaha then-flagship dx7 second version cx5m ii cx7m/128 japan ref name= cx7/128 /ref upgraded fm system sfg-05 supported midi input thus allowed internal fm synth played external midi keyboard also later cx5m ii smaller differences later 1986 yamaha released yamaha fb-01 midi module effectively sfg-05 standalone portable case
|
Computer architecture
|
global information assurance certification global information assurance certification giac information security certification entity specialises technical practical certification well new research form giac gold program sans institute founded certification entity 1999 term giac trademarked escal institute advanced technologies giac provides set vendor-neutral computer security certifications linked training courses provided sans giac specific leading edge technological advancement security order keep ahead black hat techniques papers written individuals pursuing giac certifications presented sans reading room giac website initially sans giac certifications required written paper practical specific area certification order achieve certification april 2005 sans organization changed format certification breaking two separate levels silver level certification achieved upon completion multiple choice exam gold level certification obtained completing research paper silver level prerequisite january 21 2017 giac granted 89,827 certifications worldwide
|
Computer security
|
burner game allows player control f-14 tomcat jet airplane player mission destroy enemy jets 18 stages start game player takes aircraft carrier called sega enterprise shares similar name one used 1986 film top gun also reference company name time sega enterprises ltd. arcade version jet employs machine gun limited number heat-seeking missiles master system version player unlimited missiles weapons replenished another aircraft beating stages aircraft cannon missile buttons controlled integrated flight stick game released two variations us standard upright cabinet rotating cockpit version cockpit version seat rotated horizontally cockpit rotated vertically featured two speakers head-level stereo sound seatbelt hold player cockpit rotated cabinets contained grey monitor frame flashing lights top indicated enemy lock player craft japan also got commander cabinet moves left right game ported amiga dos based pcs amstrad cpc atari st sharp x68000 fm towns commodore 64 master system pc engine sega saturn pc msx zx spectrum c64 two versions european version u.s. gold u.s. version activision weebee games port burner 32x done rutubo games known burner complete japan europe unlicensed nes port game developed tengen also exists reworked sunsoft japanese-exclusive port console port burner game boy advance included arcade 4 pack named sega arcade gallery computer gaming world reviewed burner master system citing aircraft depicted remarkable detail spectacular scenery excellent explosions later review pc much critical giving game one star five stating inferior arcade version zx spectrum 1988 conversion burner activision well-received sinclair user describing top-class coin-op conversion destined top charts giving 90 whilst crash magazine gave 86 overall reviewing 32x version gamepro commented graphics sound gameplay great difference genesis version burner ii minor graphical audio enhancements making worthwhile gamers never played burner game burner followed burner ii released year consider game revision predecessor rather entirely new game practice later repeated sega galaxy force galaxy force 2 although burner brand long dormant sega created number aerial combat games centered f-14 tomcat many similar features frequently regarded part series include sequel strike fighter later rebranded burner iii home release later games associated series include sky target retained similar gameplay presentation original addition 3d graphics sega strike fighter arcade flight combat game featured free-roaming movement boasting similar music f/a-18 hornet main plane 2006 sega released new sequel sega lindbergh hardware burner climax first arcade game bear brand since burner ii burner climax later ported xbox live arcade psn followed spinoff psp 2007 burner climax de-listed december 2014 leaving game longer available purchase march 2019 burner climax brought back digital platforms free ads sega ’ “ sega forever ” brand name emulated version burner playable in-game arcade shenmue 2 burner stage hazard final stage madworld shown replica jet spewing flames immediately incinerate enemy thrown plane burner makes cameo fighters megamix accessed cheat code music burner appears remix chapter 8 entitled route 666 bayonetta 2009 developed platinumgames published sega remix reused super smash bros. wii u super smash bros ultimate bayonetta stage umbra clock tower level based burner appears 2012 racing game sonic all-stars racing transformed f-14 tomcat also appears air vehicle unlockable character ages song burner ii appears 2010 rhythm game playable level sung character meiko arcade game appears 1990 hbo film dawn early light flight ready room b-52 bomber pilots lead character seen playing game tomcat crashing arcade version appears 1991 movie suburban commando starring hulk hogan shep ramsey plays game arcade scene however child playing acted space shooter game instead deluxe cabinet appears played john connor t-1000 searches galleria
|
Computer architecture
|
url redirection url redirection also called url forwarding world wide web technique making web page available one url address web browser attempts open url redirected page different url opened similarly domain redirection domain forwarding pages url domain redirected different domain wikipedia.com wikipedia.net automatically redirected wikipedia.org url redirection done various reasons several reasons use url redirection user might mistype url example example.com exmaple.com organizations often register misspelled domains redirect correct location example.com addresses example.com example.net could redirect single domain web page example.org technique often used reserve top-level domains tld name make easier true .edu .net redirect recognizable .com domain web pages may redirected new domain three reasons url redirects incoming links outdated url sent correct location links might sites realized change bookmarks/favorites users saved browsers applies search engines often older/outdated domain names links database send search users old urls using moved permanently redirect new url visitors still end correct page also next search engine pass search engine detect use newer url access logs web servers keep detailed information visitors came browsed hosted site however log links visitors left visitor browser need communicate original server visitor clicks outgoing link information captured several ways one way involves url redirection instead sending visitor straight site links site direct url original website domain automatically redirects real target technique bears downside delay caused additional request original website server added request leave trace server log revealing exactly link followed also privacy issue technique also used corporate websites implement statement subsequent content another site therefore necessarily affiliated corporation scenarios displaying warning causes additional delay web applications often include lengthy descriptive attributes urls represent data hierarchies command structures transaction paths session information practice results url aesthetically unpleasant difficult remember may fit within size limitations microblogging sites url shortening services provide solution problem redirecting user longer url shorter one sometimes url page changes even though content stays therefore url redirection help users bookmarks routinely done wikipedia whenever page renamed post/redirect/get prg web development design pattern prevents duplicate form submissions user clicks refresh button submitting form creating intuitive interface user agents users redirects effectively used targeting purposes like geotargeting device targeting become increasingly important rise mobile clients two approaches serve mobile users make website responsive redirect mobile website version mobile website version offered users mobile clients automatically forwarded corresponding mobile content device targeting client-side redirects non-cacheable server-side redirects used geotargeting approach offer localized content automatically forward user localized version requested url helpful websites target audience one location and/or language usually server-side redirects used geotargeting client-side redirects might option well depending requirements redirects used manipulate search engines unethical intentions e.g. url hijacking goal misleading redirects drive search traffic landing pages enough ranking power remotely related search target approach requires rank range search terms number urls would utilize sneaky redirects forward searcher target page method revival uprise mobile devices device targeting url hijacking off-domain redirect technique exploited nature search engine handling temporary redirects temporary redirect encountered search engines decide whether assign ranking value url initializes redirect redirect target url url initiates redirect may kept show search results redirect indicates temporary nature certain circumstances possible exploit behaviour applying temporary redirects well-ranking urls leading replacement original url search results url initialized redirect therefore stealing ranking method usually combined sneaky redirects re-target user stream search results target page search engines developed efficient technologies detect kinds manipulative approaches major search engines usually apply harsh ranking penalties sites get caught applying techniques like url redirection sometimes used part phishing attacks confuse visitors web site visiting modern browsers always show real url address bar threat lessened however redirects also take sites otherwise attempt attack ways example redirect might take user site would attempt trick downloading antivirus software installing trojan sort instead link clicked browser sends along http request field called referer indicates source link field populated url current web page end logs server serving external link since sensitive pages may sensitive urls example codice_2 desirable codice_1 url leave organization redirection page performs referrer hiding could embedded external urls transforming example codice_4 codice_5 technique also eliminates potentially sensitive information referer url session id reduce chance phishing indicating end user passed clear gateway another site several different kinds response browser result redirection vary whether affect http headers html content techniques used typically depend role person implementing access different parts system example web author control headers might use refresh meta tag whereas web server administrator redirecting pages site likely use server configuration simplest technique ask visitor follow link new page usually using html anchor like method often used fall-back — browser support automatic redirect visitor still reach target document following link http protocol used world wide web redirect response status code beginning 3 causes browser display different page client encounters redirect needs make number decisions handle redirect different status codes used clients understand purpose redirect handle caching request method use subsequent request http/1.1 defines several status codes redirection rfc 7231 status codes require url redirect target given location header http response 300 multiple choices usually list choices body message show default choice location header status codes 304 modified 305 use proxy redirects http response 301 moved permanently redirect looks like http/1.1 301 moved permanently location http //www.example.org/ content-type text/html content-length 174 html head title moved /title /head body h1 moved /h1 p page moved href= http //www.example.org/ http //www.example.org/ /a /p /body /html web authors producing html content ca n't usually create redirects using http headers generated automatically web server program serving html file usually true even programmers writing cgi scripts though servers allow scripts add custom headers e.g enabling non-parsed-headers many web servers generate 3xx status code script outputs location header line example php one use header function headers may required prevent caching programmer must ensure headers output body may fit easily natural flow control code help frameworks server-side content generation buffer body data asp scripting language also accomplished using codice_6 codice_7 http/1.1 allows either relative uri reference absolute uri reference uri reference relative client computes required absolute uri reference according rules defined rfc 3986 apache http server mod_alias extension used redirect certain requests typical configuration directives look like flexible url rewriting redirection apache mod_rewrite used e.g. redirect requests canonical domain name configuration applied one sites server server configuration files single content directory codice_8 file nginx integrated http rewrite module used perform advanced url processing even web-page generation return directive showing example advanced use rewrite module mdoc.su implements deterministic url shortening service entirely help nginx configuration language alone example request /dragonflybsd/hammer.5 come along would first redirected internally /d/hammer.5 first rewrite directive affecting internal state without http replies issued client yet second rewrite directive http response 302 found status code would issued client actually redirect external cgi script web-man netscape introduced meta refresh feature refreshes page certain amount time specify new url replace one page another supported web browsers timeout zero seconds effects immediate redirect treated like 301 permanent redirect google allowing transfer pagerank target page example simple html document uses technique technique used web authors meta tag contained inside document meta tag must placed head section html file number 0 example may replaced another number achieve delay many seconds anchor body section users whose browsers support feature effect achieved http codice_9 header response easier generate cgi programs one need change default status code simple cgi program effects redirect note usually http server adds status line content-length header automatically w3c discourage use meta refresh since communicate information either original new resource browser search engine w3c web content accessibility guidelines 7.4 discourage creation auto-refreshing pages since web browsers allow user disable control refresh rate articles written issue include w3c web content accessibility guidelines 1.0 ensure user control time-sensitive content changes use standard redirects n't break back button core techniques web content accessibility guidelines 1.0 section 7 javascript cause redirect setting codice_10 attribute e.g window.location='http //www.example.com/' normally javascript pushes redirector site url browser history cause redirect loops users hit back button following command prevent type behaviour window.location.replace 'http //www.example.com/ however http headers refresh meta tag may preferred security reasons javascript executed browsers many web crawlers slightly different effect achieved creating inline frame one main difference redirect methods frame redirect browser displays url frame document url target page url bar cloaking technique may used reader sees memorable url fraudulently conceal phishing site part website spoofing html5 effect could done html frame contains target page one redirect may lead another example url http //wikipedia.com *.com domain first redirected https //www.wikipedia.org/ domain name .org navigate language-specific site unavoidable different links chain served different servers though minimised rewriting url much possible server returning browser redirect wikipedia redirecting pages https default since 2015 sometimes mistake cause page end redirecting back possibly via pages leading infinite sequence redirects browsers stop redirecting certain number hops display error message http/1.1 standard states client detect intervene cyclical redirections i.e. infinite redirection loops note earlier version specification recommended maximum five redirections rfc 2068 section 10.3 content developers need aware clients might implement fixed limitation note urls sequence might repeat e.g http //www.example.com/1 http //www.example.com/2 http //www.example.com/3 ... exist services perform url redirection demand need technical work access web server site hosted redirect service information management system provides internet link redirects users desired content typical benefit user use memorable domain name reduction length url web address redirecting link also used permanent address content frequently changes hosts similarly domain name system hyperlinks involving url redirection services frequently used spam messages directed blogs wikis thus one way reduce spam reject edits comments containing hyperlinks known url redirection services however also remove legitimate edits comments may effective method reduce spam recently url redirection services taken using ajax efficient user friendly method creating shortened urls major drawback url redirection services use delay pages frame based advertising generate revenue first redirect services took advantage top-level domains tld .to tonga .at austria .is iceland goal make memorable urls first mainstream redirect service v3.com boasted 4 million users peak 2000 v3.com success attributed wide variety short memorable domains including r.im go.to i.am come.to start.at v3.com acquired fortunecity.com large free web hosting company early 1999 sales price top level domains started falling 70.00 per year less 10.00 use redirection services declined launch tinyurl 2002 new kind redirecting service born namely url shortening goal make long urls short able post internet forums since 2006 140 character limit extremely popular twitter service short url services heavily used redirection services hide referrer placing intermediate page page link destination although conceptually similar url redirection services serve different purpose rarely attempt shorten obfuscate destination url intended side-effect hide referrer information provide clear gateway websites type redirection often used prevent potentially-malicious links gaining information using referrer example session id query string many large community websites use link redirection external links lessen chance exploit could used steal account information well make clear user leaving service lessen chance effective phishing simplistic example service written php example check called e.g referrer although could spoofed also check url provided means malicious person could link redirection page using url parameter his/her selection page uses web server resources url redirection abused attackers phishing attacks open redirect covert redirect open redirect application takes parameter redirects user parameter value without validation covert redirect application takes parameter redirects user parameter value without sufficient validation disclosed may 2014 mathematical doctoral student wang jing nanyang technological university singapore
|
Web technology
|
bcachefs bcachefs copy-on-write cow file system linux-based operating systems primary developer kent overstreet first announced 2015 efforts ongoing included mainline linux kernel intended compete modern features zfs btrfs speed performance ext4 xfs bcachefs copy-on-write cow file system linux-based operating systems planned existing features bcachefs include caching full file-system encryption using chacha20 poly1305 algorithms native compression via zlib lz4 zstandard snapshots crc-32c 64-bit checksumming use multiple block devices including raid configurations bcachefs provides functionality bcache block-layer cache system linux bcachefs shares 80 code primary development kent overstreet developer bcache describes prototype ideas became bcachefs overstreet intends bcachefs replace bcache overstreet stated development bcachefs began bcache developers realized codebase evolving ... full blown general-purpose posix filesystem really clean elegant design within took direction time bcache merged 2013 mainline linux kernel overstreet left job google work full-time bcachefs years unfunded development overstreet announced bcachefs 2015 point called code less feature complete called testers contributors intended advanced file system modern features like zfs btrfs speed performance file systems ext4 xfs 2017 overstreet receiving financial support development bcachefs via patreon mid-2018 on-disk format settled patches submitted review bcachefs included mainline linux kernel yet accepted
|
Computer file systems
|
sakhr computers sakhr computers developed kuwaiti company al alamiah produced arabic-language version msx computers 1980s products included msx2 msx2+ yamaha ax100 models latter known sakhr msx ax170 company also first convert basic computer language arabic
|
Computer architecture
|
asci white asci white supercomputer lawrence livermore national laboratory california briefly fastest supercomputer world computer cluster based ibm commercial rs/6000 sp computer 512 nodes interconnected asci white node containing sixteen 375mhz ibm power3-ii processors total asci white 8,192 processors 6terabytes tb memory 160tb disk storage almost exclusively used large-scale computations requiring dozens hundreds thousands processors computer weighed 106tons consumed 3mw electricity 3mw needed cooling theoretical processing speed 12.3teraflops tflops system ran ibm aix operating system asci white made three individual systems 512-node white 28-node ice 68-node frost system built poughkeepsie new york completed june 2000 transported specially built facilities california officially dedicated august 15 2001 peak performance 12.3tflops achieved widely accepted linpack tests system cost us 110 million built stage three accelerated strategic computing initiative asci started u.s. department energy national nuclear security administration build simulator replace live wmd testing following moratorium testing started president george h. w. bush 1992 extended bill clinton 1993 machine decommissioned beginning july 27 2006
|
Distributed computing architecture
|
gpgmail gpgmail extension apple mail provides public key email encryption signing gpgmail works macos actual cryptographic functionality handled gnu privacy guard gpgmail first released february 7 2001 stéphane corthésy since 2010 maintained gpgtools gnu privacy guard free open-source software use gpgmail requires purchase support plan september 21 2018 developer introduced gpgmail 3.0 part gpg suite 2018.4 new software release included support macos mojave release developer removed free license option gpgmail lot users relied automated upgrades caught surprise prompted significant backlash community licensing change identified release notes gpg suite 2018.4 many believed big change required prominent notification avoid perception bait switch
|
Computer security
|
servicemax servicemax global market-leader service execution management software category includes field service management asset service management servicemax provides cloud-based software platform improves productivity complex equipment-centric service execution oems operators 3rd-party service providers servicemax platform saas software service software running salesforce force.com cloud technology servicemax cloud-based mobile-ready field service software solution supports companies across industries manage work orders plan schedule work assignments provide mobile technician enablement contracts entitlements proactive maintenance parts inventory management servicemax platform designed optimize service execution processes used service technicians dispatchers service planners managers customers include medical device manufacturing industrial manufacturing food beverage equipment buildings construction technology oil gas power utilities industries servicemax software primarily used enterprise size customers october 2018 servicemax introduced asset service management solution equipment operators augmenting existing field service management software typically used original equipment manufacturers service organizations commercial service operations february 2019 servicemax acquired zinc adding secure real-time communications solution portfolio zinc mode communications offering provides 1:1 group messaging voice video content sharing top-down broadcasts hotlines communications analytics recent areas innovation include capabilities complex jobs functionality crew management shift planning maxplore technologies founded athani krishnaprasad hari subramanian consulting company focusing customer relationship management client requested maxplore build field service module salesforce platform project took 2 weeks 2007 entered “ appexchange challenge ” dreamforce conference project 2 million funding emergence capital went win force million dollar challenge 2008 company changed name servicemax february 2019 servicemax acquired zinc company providing frictionless way service workers get share knowledge real-time 2016 servicemax received 204 million funding company completed 82 million series f round august 2015 led premjiinvest ge march 2014 company received 71 million series e funding led meritech capital partners november 2012 servicemax received 27 million series funding round june 2011 company received 14 million series c funding led mayfield fund april 2010 servicemax received 8 million series b funding led trinity ventures november 14 2016 general electric co. ge digital unit announced deal buy servicemax 915 million acquisition completed january 10 2017 december 13 2018 ge digital silverlake announced agreement ge digital sell majority stake servicemax ge retained 10 equity ownership company
|
Distributed computing architecture
|
reboot restore software ‘ reboot restore ’ system restore technology enables restoring user-defined system configuration computing device every restart technology helps maintain systems optimum working conditions useful especially multi-user computing environments deploying solutions based reboot restore technology enables users define particular system configuration desired state baseline point would restored reboot baseline set reboot restore software continues restore particular configuration every time device restarted switched shutdown reboot restore software helps maintaining optimal system configuration quite effective multi-user computing environment technology prevents types alterations baseline configuration whether user inflicted automatic alterations end-users primarily changes system settings installing uninstalling software applications enabling disabling specific functionalities automatic alterations include cookies add-ons browser extensions several types temporary files often get downloaded background online session also rolls back malicious alterations made malware elusively penetrate system attempts corrupt reboot restore software solutions built simplify process maintaining optimal system configuration devices multi-user computing environment public libraries computer labs educational institutes k-12 colleges universities training centers public access kiosks due constant use multiple people wide range purposes devices become susceptible performance deterioration malware infiltration events system malfunction failure takes considerably longer time troubleshoot issue using conventional practices like resetting reimaging may lead prolonged downtime causing poor user experience potential loss business opportunity higher maintenance costs restore reboot functionality ensures best system configuration pristine state maintained every public-access computer without long-drawn troubleshooting steps instant restoration technology empowers end-users resolve system issues simply restarting device significantly reduces intervention end-users experience optimum system performance pristine configuration restored every reboot technology helps deliver maximum system uptime improves operational efficiency resource utilization system administrators corporates deploy reboot restore solutions create prestige environments without need constant troubleshooting use software protect system drive allocate separate data partition user application data stored redirected initially named shared computer toolkit windows steadystate freeware reboot restore solution offered microsoft compatible windows xp windows vista operating systems windows steadystate discontinued december 2010 software primarily used educational institutes public libraries steadystate features windows disk protection wdp functionality enabled redirects user-generated changes cache software three modes discard persist commit discard mode clears cache reboot restores original configuration persist mode retains cache specific time admins could opt discard commit changes commit mode changes permanently written hard disk usual deep freeze faronics one first rollback software solutions leverage reboot restore technology releasing first windows solution 1999 followed mac os solution 2005 deep freeze uses patented technology redirects information written hard drive partition allocation table leaving original data intact redirected information allocation table longer referenced computer restarted therefore restoring computer back original state disk sector level last byte extending functionalities reboot restore technology software provision thawspaces thawed partitions permanently saving user-generated data without altering baseline configuration thawspace virtual space system administrators create within deep freeze ecosystem hard disk partition content stored thawspace retained across reboots thawed partitions parts hard disk exempted effects reboot restore technology microsoft apple inc. offer restoration tools though based reboot restore technology embedded respective operating systems system restore inbuilt feature windows available latest versions os reverts system files settings previous point time without affecting personal files enabled software automatically creates restore points regular intervals every major instance configuration alteration like driver update new application installation device malfunctions running system restore rolls back configuration restore point particular issue exist reset option introduced windows 8 used restoring systems factory defaults re-installs windows os permanently discards files system settings pre-installed applications time machine macos functions backup utility restoration program creates incremental snapshots system configuration periodically requires external storage device backing macos backup later used restore previous configuration required software also used restore specific items like deleted emails older versions files rather entire configuration also introduced windows 8 refresh re-installs windows os retains user files pre-installed applications installed users running reset option advised refresh fails resolve issue
|
Computer security
|
nokia n810 nokia n810 internet tablet internet appliance nokia announced 17 october 2007 web 2.0 summit san francisco despite nokia strong association cellular products n810 like preceding tablets produced nokia phone instead allowed user browse internet communicate using wi-fi networks mobile phone via bluetooth built hardware software nokia n800 features added removed nokia n810 featured maemo linux distribution operating system based maemo 4.0 featured microb mozilla-based mobile browser gps navigation application new media player refreshed interface nokia n810 much common n800 internet tablet os 2008 operated significant differences two new features nokia n810 1 april 2008 nokia announced wimax equipped version n810 called n810 wimax edition device identical specifications original n810 included wimax radio use initially sprint xohm network featured color change light gray dark blue black well larger case-back bulge accommodate antenna efficient required bands production wimax edition nokia n810 ended january 2009 n810 like nokia internet tablets ran maemo similar many handheld operating systems provided home screen — central point applications settings accessed home screen divided areas launching applications menu bar large customisable area could display information rss reader internet radio player google search box example maemo modified version debian gnu/linux n810 bundled several applications including mozilla-based microb browser adobe flash gizmo skype mobile firefox fennec also made available n810 promised make users forget clunky stripped-down mobile web 're used installation added mozilla repository application manager allowing automatic notification updates
|
Operating systems
|
frequency-hopping spread spectrum frequency-hopping spread spectrum fhss method transmitting radio signals rapidly switching carrier among many frequency channels using pseudorandom sequence known transmitter receiver used multiple access method code division multiple access cdma scheme frequency-hopping code division multiple access fh-cdma available frequency band divided sub-frequencies signals rapidly change hop among predetermined order interference specific frequency affect signal short interval fhss however cause interference adjacent direct-sequence spread spectrum dsss systems adaptive frequency-hopping spread spectrum afh specific type fhss used bluetooth wireless data transfer spread-spectrum transmission offers three main advantages fixed-frequency transmission spread-spectrum signals highly resistant deliberate jamming unless adversary knowledge spreading characteristics military radios use cryptographic techniques generate channel sequence control secret transmission security key transec sender receiver share advance frequency hopping provides limited protection eavesdropping jamming modern military frequency hopping radios also employ separate encryption devices ky-57 speech security equipment u.s. military radios use frequency hopping include jtids/mids family quick aeronautical mobile communications system sincgars combat net radio link-16 us since federal communications commission fcc amended rules allow frequency hopping spread spectrum systems unregulated 2.4 ghz band many consumer devices band employed various spread-spectrum modes walkie-talkies employ frequency-hopping spread spectrum technology developed unlicensed use 900 mhz band several radios marketed name extreme radio service exrs despite name similarity frs allocation system proprietary design rather official fcc allocated service frequency-hopping spread spectrum technology also used many hobby rc radio controlled transmitters receivers used model cars airplanes drones type multiple access achieved allowing hundreds transmitter/receiver pairs operated simultaneously band contrast previous fm rc systems limited simultaneous channels motorola deployed business-banded license-free digital radio uses fhss technology dtr series models 410 550 650 overall bandwidth required frequency hopping much wider required transmit information using one carrier frequency however transmission occurs small portion bandwidth given time effective interference bandwidth really providing extra protection wideband thermal noise frequency-hopping approach reduce degradation caused narrowband interference sources one challenges frequency-hopping systems synchronize transmitter receiver one approach guarantee transmitter use channels fixed period time receiver find transmitter picking random channel listening valid data channel transmitter data identified special sequence data unlikely occur segment data channel segment also checksum integrity checking identification transmitter receiver use fixed tables channel sequences synchronized maintain communication following table channel segment transmitter send current location table us fcc part 15 unlicensed spread spectrum systems 902–928 mhz 2.4 ghz bands permits power allowed non-spread-spectrum systems frequency hopping direct sequence systems transmit 1 watt thousand-fold increase 1 milliwatt limit non-spread-spectrum systems federal communications commission fcc also prescribes minimum number channels maximum dwell time channel real multipoint spread spectrum radio system space allows possibility multiple transmissions frequency using multiple radios geographic area creates possibility system data rates higher shannon limit single channel spread spectrum systems violate shannon limit spread spectrum systems rely excess signal noise ratios sharing spectrum property also seen mimo dsss systems beam steering directional antennas also facilitate increased system performance providing isolation remote radios 1899 guglielmo marconi experimented frequency-selective reception attempt minimise interference earliest mentions frequency hopping open literature us patent 725,605 awarded nikola tesla march 17 1903 radio pioneer jonathan zenneck book wireless telegraphy german 1908 english translation mcgraw hill 1915 although zenneck states telefunken already tried nikola tesla ’ mention phrase “ frequency hopping ” directly certainly alludes entitled method signaling patent describes system would enable radio communication without danger signals messages disturbed intercepted interfered way german military made limited use frequency hopping communication fixed command points world war prevent eavesdropping british forces technology follow sequence polish engineer inventor leonard danilewicz came idea 1929 several patents taken 1930s including one willem broertjes issued aug. 2 1932 world war ii us army signal corps inventing communication system called sigsaly incorporated spread spectrum single frequency context however sigsaly top-secret communications system existence become known 1980s 1942 actress hedy lamarr composer george antheil received secret communications system intended early version frequency hopping supposed use piano-roll change among 88 frequencies intended make radio-guided torpedoes harder enemies detect jam record working device ever produced patent rediscovered 1950s patent searches private companies independently developed code division multiple access non-frequency-hopping form spread-spectrum cited numerous times since practical application frequency hopping developed ray zinn co-founder micrel corporation zinn developed method allowing radio devices operate without need synchronize receiver transmitter using frequency hopping sweep modes zinn method primarily applied low data rate wireless applications utility metering machine equipment monitoring metering remote control 2006 zinn received wireless device method using frequency hopping sweep modes adaptive frequency-hopping spread spectrum afh used bluetooth improves resistance radio frequency interference avoiding crowded frequencies hopping sequence sort adaptive transmission easier implement fhss dsss key idea behind afh use “ good ” frequencies avoiding bad frequency channels—perhaps bad frequency channels experiencing frequency selective fading perhaps third party trying communicate bands perhaps bands actively jammed therefore afh complemented mechanism detecting good/bad channels however radio frequency interference dynamic strategy “ bad channel removal ” applied afh might work well example several colocated frequency-hopping networks bluetooth piconet mutually interfering strategy afh fails avoid interference problem dynamic interference gradual reduction available hopping channels backward compatibility legacy bluetooth devices resolved version 1.2 bluetooth standard 2003 strategies dynamic adaptation frequency hopping pattern reported literature situation often happen scenarios use unlicensed spectrum addition dynamic radio frequency interference expected occur scenarios related cognitive radio networks devices exhibit frequency-agile operation chirp modulation seen form frequency-hopping simply scans available frequencies consecutive order communicate concept also use combination frequency hopping spread spectrum ofdm non-orthogonal frequency-division multiplexing n-ofdm signals increase data performance
|
Internet protocols
|
lapb link access procedure balanced lapb implements data link layer defined x.25 protocol suite lapb bit-oriented protocol derived hdlc ensures frames error free correct sequence lapb specified itu-t recommendation x.25 iso/iec 7776 implements connection-mode data link service osi reference model defined itu-t recommendation x.222 lapb used manage communication packet framing data terminal equipment dte data circuit-terminating equipment dce devices x.25 protocol stack lapb essentially hdlc asynchronous balanced mode abm lapb sessions established either dte dce station initiating call determined primary responding station secondary lapb mainly used transfer data upper layer frame flag – value flag always 0x7e order ensure bit pattern frame delimiter flag appear data field frame therefore cause frame misalignment technique known bit stuffing used transmitter receiver address field – lapb field meaning since protocol works point point mode dte network address represented layer 3 packets byte therefore put different use separates link commands responses two values 0x01 0x03 01 identifies frames containing commands dte dce responses commands dce dte 03 used frames containing commands dce dte responses dte dce therefore one side must configured layer 2 dte layer 2 dce must confuse familiar layer 1 dce dte designations control field – serves identify type frame addition includes sequence numbers control features error tracking according frame type modes operation – lapb works asynchronous balanced mode abm mode balanced i.e. master/slave relationship signified sabm e /sm frame station may initialize supervise recover errors send frames time dte dce treated equals fcs – frame check sequence enables high level physical error control allowing integrity transmitted frame data checked window size – lapb supports extended window size modulo 128 modulo 32768 maximum number outstanding frames acknowledgment raised 7 modulo 8 127 modulo 128 32767 modulo 32768 lapb master/slave node relationships sender uses poll bit command frames insist immediate response response frame bit becomes receivers final bit receiver always turns final bit response command sender poll bit set p/f bit generally used either end becomes unsure proper frame sequencing possible missing acknowledgment necessary re-establish point reference also used trigger acknowledgment outstanding i-frames following table shows addresses placed lapb frame issuing commands responses dte dce dce dte using single link operation multilink operation
|
Internet protocols
|
xerox operating system xerox operating system xos operating system xds sigma series computers optimized direct replacement ibm dos/360 installations provide real-time timesharing support system developed beginning 1969 xerox french firm bull xos successful europe us unable compete ibm 1972 35 xos installations europe compared 2 us
|
Operating systems
|
scilab image processing sip toolbox processing images scilab sip meant free complete useful image toolbox scilab goals include tasks filtering blurring edge detection thresholding histogram manipulation segmentation mathematical morphology color image processing though sip still early development currently import output image files many formats including bmp jpeg gif png tiff xpm pcx sip uses imagemagick accomplish sip licensed gpl
|
Programming language topics
|
hacking team hackingteam milan-based information technology company sells offensive intrusion surveillance capabilities governments law enforcement agencies corporations remote control systems enable governments corporations monitor communications internet users decipher encrypted files emails record skype voice ip communications remotely activate microphones camera target computers company criticized providing capabilities governments poor human rights records though hackingteam states ability disable software used unethically italian government restricted license business countries outside europe hackingteam employs around 40 people italian office subsidiary branches annapolis washington d.c. singapore products use dozens countries across six continents hackingteam founded 2003 two italian entrepreneurs david vincenzetti valeriano bedeschi 2007 company invested two italian vc fondo next innogest milan police department learned company hoping use tool spy italian citizens listen skype calls police contacted vincenzetti asked help hackingteam became first sellers commercial hacking software police ” according former employee alberto pelliccione company began security services provider offering penetration testing auditing defensive capabilities clients pelliccione states malware offensive capabilities developed accounted larger percentage revenues organization pivoted offensive direction became increasingly compartmentalized pelliccione claims fellow employees working aspects platform – example android exploits payloads – would communicate one another possibly leading tensions strife within organization february 2014 report citizen lab identified organisation using hosting services linode telecom italia rackspace noc4hosts notorious bullet proof hosting company santrex july 5 2015 company suffered major data breach customer data software code internal documents e-mails see § 2015 data breach april 2nd 2019 hackingteam acquired inthecyber create memento labs hackingteam enables clients perform remote monitoring functions citizens via rcs remote control systems including da vinci galileo platforms hackingteam uses advanced techniques avoid draining cell phone batteries could potentially raise suspicions methods avoid detection malware payloads android blackberry apple ios linux mac os x symbian well microsoft windows windows mobile windows phone class operating systems rcs management platform allows operators remotely deploy exploits payloads targeted systems remotely manage devices compromised exfiltrate data remote analysis hackingteam criticized selling products services governments poor human rights records including sudan bahrain venezuela saudi arabia june 2014 united nations panel monitoring implementation sanctions sudan requested information hackingteam alleged sales software country contravention united nations weapons export bans sudan documents leaked 2015 data breach hackingteam revealed organization sold sudanese national intelligence security service access remote control system software 2012 960,000 euros response united nations panel company responded january 2015 currently selling sudan follow-up exchange hackingteam asserted product controlled weapon request beyond scope panel need disclose previous sales considered confidential business information u.n. disagreed view panel software ideally suited support military electronic intelligence elint operations may potentially fall category 'military ... equipment 'assistance related prohibited items secretary wrote march thus potential use targeting belligerents darfur conflict interest panel fall 2014 italian government abruptly froze hackingteam exports citing human rights concerns lobbying italian officials company temporarily back right sell products abroad july 5 2015 twitter account company compromised unknown individual published announcement data breach hackingteam computer systems initial message read since nothing hide 're publishing e-mails files source code ... provided links 400 gigabytes data including alleged internal e-mails invoices source code leaked via bittorrent mega announcement data breach including link bittorrent seed retweeted wikileaks many others social media material voluminous early analysis appeared reveal hackingteam invoiced lebanese army sudan spy tools also sold bahrain kazakhstan hackingteam previously claimed never done business sudan leaked data revealed zero-day cross-platform flash exploit cve number cve-2015-5119 dump included demo exploit opening calculator test webpage adobe patched hole july 8 2015 another vulnerability involving adobe revealed dumps took advantage buffer overflow attack adobe open type manager dll included microsoft windows dll run kernel mode attack could perform privilege escalation bypass sandbox also revealed leaked data hackingteam employees use weak passwords including 'p4ssword 'wolverine 'universo hours without response hackingteam member christian pozzi tweeted company working closely police attackers claiming regarding company true also claimed leaked archive contains virus constituted false info shortly tweets pozzi twitter account apparently compromised responsibility attack claimed hacker known phineas fisher phisher twitter phineas previously attacked spyware firm gamma international produce malware finfisher governments corporations 2016 phineas published details attack spanish english how-to others explained motivations behind attack internal documents revealed details hackingteam contracts repressive governments 2016 italian government revoked company license sell spyware outside europe without special permission hackingteam clientele include governments also corporate clients barclay bank british telecom bt united kingdom well deutsche bank germany full list hackingteam customers leaked 2015 breach disclosed documents show hackingteam 70 current customers mostly military police federal provincial governments total company revenues disclosed exceeded 40 million euros
|
Computer security
|
festi festi rootkit botnet created basis works operating systems windows family autumn 2009 first time festi came view companies engaged development sale antivirus software time estimated botnet consisted roughly 25.000 infected machines spam volume capacity roughly 2.5 billion spam emails day festi showed greatest activity 2011-2012 recent estimates dated august 2012 display botnet sending spam 250,000 unique ip addresses quarter total amount one million detected ip sending spam mails main functionality botnet festi spam sending implementation cyberattacks like distributed denial service distribution carried scheme ppi pay-per-install use preventing detection antiviruses loader extends ciphered complicates signature based detection represented data architecture botnet gathered research eset antivirus company loader downloads sets bot represents kernel-mode driver adds list drivers launching together operating system hard disk drive part bot stored responsible communication command center loading modules starting bot periodically asks command center receiving configuration loading modules jobs necessary execution researches carried specialists antivirus company eset known festi least two modules one intends spam sending botspam.dll another implementation cyberattacks like distributed denial service botdos.dll module implementation cyberattacks like distributed denial service supports following types cyberattacks namely tcp-flood udp-flood dns-flood http -flood also flood packets random number issue used protocol expert kaspersky lab researching botnet drew output modules used list includes module socks-server implementation botsocks.dll tcp udp protocols module remote viewing control computer user botremote.dll module implementing search disk remote computer local area network botsearch.dll remote computer connected grabber-modules browsers known present time botgrabber.dll modules never saved hard disk drive almost impossible detection bot uses client-server model functioning implements protocol network interaction command center used receiving configuration botnet loading modules also obtaining jobs command center notification command center execution data encoded interferes determination contents network traffic case installation bot switches system firewall hides kernel-mode driver keys system registry necessary loading operation protects registry keys deleting operation network occurs low level allows bypass network filters antivirus software easily use network filters observed prevent installation bot checks whether launched virtual machine case positive result check stops activities festi periodically checks existence debugger able remove breakpoints festi created use object-oriented technology software development strongly complicates researches method reverse engineering bot easily ported operating systems control botnet festi implemented means web interface carried via browser according specialists antivirus company eset american journalist blogger brian krebs expert information security field according american journalist new york times newspaper andrew kramer also sources close russian intelligence services architect developer botnet festi — russian hacker igor artimovich conclusion possible tell botnet festi one powerful botnets sending spam carrying attacks like distributed denial service principles festi botnet constructed increase bot lifetime system much possible hinder bot detection antivirus software network filters mechanism modules allows expand functionality botnet side means creation loading necessary modules achievement different purposes object-oriented approach development complicates botnet researching use methods reverse engineering gives chance bot porting operating systems accurate demarcation specific concrete operating system functionality remaining logic bot powerful systems counteraction detection debugging make festi bot almost invisible stealthy system bindings use reserve command centers gives chance restoration control botnet change command center festi atypical example malicious software authors approached process development extremely seriously
|
Computer security
|
beaker web browser beaker free open-source web browser currently development blue link labs beaker browser peer-to-peer technology allow users self-publish websites web apps directly browser without need set administrate separate web server host contents third-party server files websites transferred using dat hypermedia peer-to-peer protocol allows files shared hosted several users browser also supports http protocol connect traditional servers beaker built using electron framework therefore uses chromium browser renderer webpages files stored local folder published dat website made accessible users peer-to-peer protocol files seeded local folder browser active make also available browser closed user may use several alternative options host content
|
Internet protocols
|
opos opos full name ole retail pos platform specific implementation unifiedpos point sale device standard microsoft windows operating systems initiated microsoft ncr epson fujitsu-icl managed association retail technology standards opos api first published january 1996 standard uses component object model languages support com controls i.e visual c++ visual basic c used write applications opos standard specifies two levels opos control control object presents abstract hardware interface family devices receipt printer service object handles interface control object actual physical device specific model receipt printer division functionality provides way application development write abstract hardware interface allowing application work variety different hardware requirement hardware vendor supplies opos compatible service object particular hardware offering typically manufacturer point sale terminals provide along terminal operating system opos control object package software utility used configure opos settings utility specify settings opos control object indicate service object used particular opos profile point sale application starts loads opos control object opos control object turn loads service object specified current opos profile windows registry typically used persistent store device settings hardware device manufacturer normally provide utility device specific settings used service object opos deployed following operating systems
|
Operating systems
|
broadcom corporation broadcom corporation american fabless semiconductor company made products wireless broadband communication industry acquired avago technologies 2016 operates wholly owned subsidiary merged entity broadcom inc. broadcom corporation founded professor-student pair henry samueli henry nicholas ucla 1991 1995 company moved westwood los angeles office irvine california 1998 broadcom became public company nasdaq exchange ticker symbol brcm employs 11,750 people worldwide 15 countries broadcom among gartner top 10 semiconductor vendors revenue broadcom first landed fortune 500 2009 2012 broadcom total revenue 8.01 billion 2013 broadcom stood 327 fortune 500 climbed 17 places 2012 ranking 344 may 28 2015 chip maker avago technologies ltd. agreed buy broadcom corp. 37 billion cash stock closing completed february 1 2016 broadcom shareholders held 32 new singapore-based company called broadcom limited hock tan avago president ceo named ceo new combined company dr. samueli became chief technology officer member combined company board dr. nicholas serves strategic advisory role within new company new merged entity named broadcom limited inherits ticker symbol avgo brcm ticker symbol retired may 2016 cypress semiconductor announced acquire broadcom corporation full portfolio iot products 550 million deal cypress acquires broadcom iot products intellectual property wi-fi bluetooth zigbee connectivity well broadcom wiced platform sdk developers deal combined broadcom developer tools connectivity technologies iot devices cypress programmable system-on-a-chip soc products provide memory computing graphics processing low-power devices april 26 2009 broadcom settled four years legal battles wireless patents qualcomm inc. another fabless semiconductor company headquartered san diego california deal ended patent litigation well complaints anti-competitive behavior trade commissions united states europe south korea part settlement qualcomm paid 891 million cash broadcom four-year period ending june 2013 june 2007 u.s. international trade commission blocked import new cell phone models based particular qualcomm microchips found qualcomm microchips infringe patents owned broadcom january 2017 ftc sued qualcomm allegedly engaging unlawful tactics maintain monopoly cellular-communications chips january 17 2018 reported ftc investigating whether broadcom engaged anti-competitive tactics negotiations customers probe ongoing several months july 14 2006 broadcom announced subtract 750 million earnings due stock options irregularities september 8 2006 amount doubled 1.5 billion company may also owe additional taxes january 24 2007 announced restatement financial results 1998 2005 totaled 2.22 billion may 15 2008 broadcom cto samueli resigned chairman board took leave absence chief technology officer named civil complaint u.s. securities exchange commission sec june 5 2008 broadcom co-founder former ceo henry nicholas former cfo william ruehle indicted charges illegal stock-option backdating nicholas also indicted violations federal narcotics laws however december 2009 federal judge cormac j. carney threw options backdating charges nicholas ruehle finding federal prosecutors improperly tried prevent three defense witnesses testifying broadcom product line spans computer telecommunication networking company products enterprise/metropolitan high-speed networks well products soho small-office home-office networks products include transceiver processor ics ethernet wireless lans cable modems digital subscriber line dsl servers home networking devices router switches port-concentrators cellular phones gsm/gprs/edge/w-cdma/lte also known series high-speed encryption co-processors offloading processor-intensive work dedicated chip thus greatly speeding tasks utilize encryption many practical benefits e-commerce pgp gpg secure communications company also produces ics carrier access equipment audio/video processors digital set-top boxes digital video recorders bluetooth wi-fi transceivers rf receivers/tuners satellite tv major customers include apple hewlett-packard motorola ibm dell asus lenovo linksys logitech nintendo nokia nortel avaya tivo tenda cisco systems september 2011 broadcom shut digital tv operations broadcom also shut blu-ray chip business closure businesses began september 19 2011 june 2 2014 broadcom announced intentions exit cellular baseband business vendors included broadcom nics products example dell poweredge m-series blade-server products may fitted dell-supplied dual port broadcom netxtreme 5709 gigabit ethernet port adapters another large market hardware switches vendors offer switching equipment based broadcom hardware firmware e.g dell powerconnect classics well-known vendors use broadcom hardware write firmware latest broadcom trident+ asic used many high-speed 10gb+ switches largest switch-vendors cisco nexus switches running nx-os dell force10 dell networking running ftos/dnos arista 7050-series switches ibm/bnt 8264 juniper qfx3500 latest 'member trident family trident ii xgs support 32 x 40g ports 104 x 10g ports mix single chip examples switches using trident ii xgs chip dell networking s6000 cisco nexus 9000 smaller vendors like edgecore as6700 penguin arctica 3200xl quantamesh t5032 videocore gpu found systems-on-a-chip soc broadcom widely known one bcm2835 containing videocore iv found raspberry pi broadcom crystal hd video acceleration broadcom bcm43 series chips provide wifi support many android iphone devices models include bcm4339 used phones nexus 5 2013 bcm4361 used samsung galaxy s8 2017 soc devices cortex r4 processing mac mlme layers proprietary broadcom processor 802.11 physical layer chips also handle wi-fi direct bluetooth nfc april 2017 google project zero investigated broadcom soc wifi stack found lacked basic exploit mitigations including stack cookies safe unlinking access permission protection allowing full device takeover wi-fi proximity alone requiring user interaction numerous smartphones apple samsung google affected broadcom authored voip codecs 2002 released open source lgpl license 2009 free open source drivers available included linux kernel source tree 802.11b/g/a/n family wireless chips broadcom produces since release 2.6.26 kernel broadcom chips kernel support require external firmware built 2003 free software foundation accused broadcom complying gnu general public license broadcom distributed gpl code driver 802.11g router chipset without making code public chipset adopted linksys later purchased cisco cisco eventually published source code firmware wrt54g wireless broadband router gpl-license 2012 linux foundation listed broadcom one top 10 companies contributing development linux kernel 2011 placing top 5 percent estimated 226 contributing companies foundation linux kernel development report also noted course year broadcom submitted 2,916 changes kernel october broadcom released parts raspberry pi userland bsd-style license according raspberry pi foundation made first arm-based multimedia soc fully functional vendor-provided opposed partial reverse-engineered fully open-source drivers although due substantial binary firmware code must executing parallel operating system executes independently prior loading operating system claim universally accepted broadcom provided linux driver broadcom crystal hd also hired eric anholt former intel employee work free open-source graphics device driver videocore iv broadcom organizes fabrication processor chip recently bcm2837 chip wifi processor bcm43438 used charitable raspberry pi foundation foundation requested help broadcom making raspberry pi card motherboard free drm corporate control kind interact hardware bought controlled children jericho2 programmable ethernet switch chip 10 tb/s switching capacity per device tomahawk 3 series supports high-density standards based 400gbe 200gbe 100gbe switching routing hyperscale cloud networks broadcom divulged bringing two variants tomahawk-3 market first full-tilt-boogie 12.8 tb/sec 256 serdes fired supporting 32 ports 400 gb/sec 64 ports 200 gb/sec 128 ports 100 gb/sec second variant tomahawk-3 160 256 serdes fired delivers 8 tb/sec aggregate bandwidth broadcom suggesting 80 ports 100 gb/sec 48 ports 100 gb/sec plus either 8 ports 400 gb/sec 16 ports 200 gb/sec 96 ports 50 gb/sec plus either 8 ports 400 gb/sec 16 ports 200 gb/sec broadcom known fabless company outsources semiconductor manufacturing foundries globalfoundries semiconductor manufacturing international corporation silterra tsmc united microelectronics corporation company based irvine california university research park university california irvine campus 2007 move previous campus near irvine spectrum many research development sites including silicon fen cambridge uk bangalore hyderabad india richmond near vancouver markham near toronto canada sophia antipolis france september 2011 broadcom bought netlogic microsystems deal 3.7 billion cash excluding around 450 million netlogic employee shareholdings transfer broadcom besides netlogic microsystems acquisition years broadcom acquired many smaller companies quickly enter new markets broadcom logo designed eliot hochberg based logo company previous name broadband telecom broadband telecom logo designed co-founder henry nicholas then-wife stacey nicholas inspired mathematical sinc function 2009 company founded broadcom foundation non-profit corporation 50m investment direction henry samueli company co-founder broadcom chief executive scott mcgregor cited history science fair involvement factor success mcgregor named foundation first president chairman
|
Computer architecture
|
message passing computer science message passing technique invoking behavior i.e. running program computer invoking program sends message process may actor object relies process supporting infrastructure select invoke actual code run message passing differs conventional programming process subroutine function directly invoked name message passing key models concurrency object-oriented programming message passing used ubiquitously modern computer software used way objects make program work means objects systems running different computers e.g. internet interact message passing may implemented various mechanisms including channels message passing technique invoking behavior i.e. running program computer contrast traditional technique calling program name message passing uses object model distinguish general function specific implementations invoking program sends message relies object select execute appropriate code justifications using intermediate layer essentially falls two categories encapsulation distribution encapsulation idea software objects able invoke services objects without knowing caring services implemented encapsulation reduce amount coding logic make systems maintainable e.g. rather if-then statements determine subroutine function call developer send message object object select appropriate code based type one first examples used domain computer graphics various complexities involved manipulating graphic objects example simply using right formula compute area enclosed shape vary depending shape triangle rectangle ellipse circle traditional computer programming would result long if-then statements testing sort object shape calling appropriate code object-oriented way handle define class called codice_1 subclasses codice_2 codice_3 turn subclasses codice_4 codice_5 simply send message codice_1 asking compute area codice_1 object invoke subclass method formula appropriate kind object distributed message passing provides developers layer architecture provides common services build systems made sub-systems run disparate computers different locations different times distributed object sending message messaging layer take care issues synchronous message passing occurs objects running time used object-oriented programming languages java smalltalk synchronous messaging analogous synchronous function call function caller waits function completes sending process waits receiving process completes make synchronous communication unworkable applications example large distributed systems may perform well enough usable large distributed systems may need operate subsystems maintenance etc imagine busy business office 100 desktop computers send emails using synchronous message passing exclusively one worker turning computer cause 99 computers freeze worker turns computer back process single email asynchronous message passing receiving object busy requesting object sends message continuing function call analogy like function call returns immediately without waiting called function complete messages sent queue stored receiving process requests receiving process processes messages sends results queue pickup original process designated next process asynchronous messaging requires additional capabilities storing retransmitting data systems may run concurrently generally handled intermediary level software often called middleware common type message-oriented middleware mom buffer required asynchronous communication cause problems full decision made whether block sender whether discard future messages blocked sender may lead deadlock messages dropped communication longer reliable synchronous communication built top asynchronous communication using synchronizer example α-synchronizer works ensuring sender always waits acknowledgement message receiver sender sends next message acknowledgement received hand asynchronous communication also built top synchronous communication example modern microkernels generally provide synchronous messaging primitive asynchronous messaging implemented top using helper threads message-passing systems use either distributed local objects distributed objects sender receiver may different computers running different operating systems using different programming languages etc case bus layer takes care details converting data one system another sending receiving data across network etc remote procedure call rpc protocol unix early example note type message passing requirement sender receiver use object-oriented programming procedural language systems wrapped treated large grained objects capable sending receiving messages examples systems support distributed objects onc rpc corba java rmi dcom soap .net remoting ctos qnx neutrino rtos openbinder d-bus distributed object systems called shared nothing systems message passing abstraction hides underlying state changes may used implementation sending messages distributed asynchronous message-passing additional overhead compared calling procedure message-passing arguments must copied new message arguments contain megabytes data must copied transmitted receiving object traditional procedure calls differ message-passing terms memory usage transfer time locality arguments passed receiver typically general purpose registers requiring additional storage transfer time parameter list containing arguments addresses bits address-passing possible distributed systems since systems use separate address spaces web browsers web servers examples processes communicate message-passing url example referencing resource without exposing process internals subroutine call method invocation exit invoked computation terminated asynchronous message-passing contrast result response arriving significant time request message sent message-handler general process messages one sender means state change reasons unrelated behavior single sender client process contrast typical behavior object upon methods invoked latter expected remain state method invocations words message-handler behaves analogously volatile object prominent mathematical models message passing actor model pi calculus mathematical terms message single means pass control object object responds message method message alan kay argued message passing important objects oop objects often over-emphasized live distributed objects programming model builds upon observation uses concept distributed data flow characterize behavior complex distributed system terms message patterns using high-level functional-style specifications
|
Distributed computing architecture
|
rule least power programming rule least power design principle suggests choosing least powerful computer language suitable given purpose stated alternatively given choice among computer languages classes range descriptive declarative procedural less procedural descriptive language one chooses one data stored language rule application principle least privilege protocol design originally proposed axiom good design term extension kiss principle applied choosing among range languages ranging explained tim berners-lee
|
Programming language topics
|
clojure clojure like closure modern dynamic functional dialect lisp programming language java platform. ref name= platform/android /ref like lisps clojure treats code data lisp macro system. ref name= reference/lisps /ref current development process community-driven ref name= dev/dev /ref overseen rich hickey benevolent dictator life bdfl clojure advocates immutability immutable data structures encourages programmers explicit managing identity states. ref name= about/state /ref focus programming immutable values explicit progression-of-time constructs intended facilitate developing robust especially concurrent programs. ref name= about/rationale /ref ref name= msdn/inside-clojure /ref type system entirely dynamic recent efforts also sought implementation gradual typing commercial support clojure provided cognitect annual clojure conferences organized every year across globe famous clojure/conj rich hickey creator clojure language clojure developed dotlisp similar project based .net platform three earlier attempts provide interoperability lisp java java foreign language interface common lisp jfli foreign object interface lisp foil lisp-friendly interface java servlets lisplets hickey spent 2½ years working clojure releasing publicly much time working exclusively clojure outside funding end time hickey sent email announcing language friends common lisp community development process community-driven managed clojure jira project page issues may filed general development discussion occurs clojure google group anyone submit issues ideas contribute patches one must sign clojure contributor agreement jira issues processed team screeners finally rich hickey approves changes rich hickey developed clojure wanted modern lisp functional programming symbiotic established java platform designed concurrency clojure approach state characterized concept identities represented series immutable states time since states immutable values number workers operate parallel concurrency becomes question managing changes one state another purpose clojure provides several mutable reference types well-defined semantics transition states clojure runs java platform result integrates java fully supports calling java code clojure ref name= about/jvm_hosted /ref clojure code called java also community uses leiningen project automation providing support maven integration leiningen handles project package management dependencies configured using clojure syntax like lisps clojure syntax built s-expressions first parsed data structures reader compiled. ref name= reference/reader /ref clojure reader supports literal syntax maps sets vectors addition lists compiled mentioned structures directly clojure lisp-1 intended code-compatible dialects lisp since uses set data structures incompatible lisps lisp dialect clojure supports functions first-class objects read–eval–print loop repl macro system clojure lisp macro system similar common lisp exception clojure version backquote termed syntax quote qualifies symbols namespace helps prevent unintended name capture binding namespace-qualified names forbidden possible force capturing macro expansion must done explicitly clojure allow user-defined reader macros reader supports constrained form syntactic extension clojure supports multimethods interface-like abstractions protocol based polymorphism data type system using records providing high-performance dynamic polymorphism designed avoid expression problem clojure support lazy sequences encourages principle immutability persistent data structures functional language emphasis placed recursion higher-order functions instead side-effect-based looping automatic tail call optimization supported jvm support natively possible explicitly using codice_1 keyword parallel concurrent programming clojure provides software transactional memory reactive agent system channel-based concurrent programming clojure 1.7 introduced reader conditionals allowing embedding clojure clojurescript code namespace transducers added method composing transformations transducers enable higher-order functions map fold generalize source input data traditionally functions operate sequences transducers allow work channels let user define models transduction primary platform clojure java target implementations exist notable clojurescript compiles ecmascript 3 clojureclr full port .net platform interoperable ecosystem survey clojure community 1,060 respondents conducted 2013 found 47 respondents used clojure clojurescript working clojure 2014 number increased 55 2015 based 2,445 respondents 66 popular clojurescript projects include implementations react library reagent re-frame rum om continued interest functional programming clojure adoption software developers java platform kept increasing language also either preferred recommended renowned software development veterans james gosling paul graham robert c. martin colloquially known uncle bob jvm ecsosystem report 2018 claimed largest survey ever java developers prepared collaboration snyk java magazine clojure ranked 2nd used programming language behind java main applications clojure used industry firms apple atlassian funding circle netflix puppet walmart well government agencies nasa also used creative computing including visual art music games poetry thoughtworks assessing functional programming languages technology radar expressed favor toward clojure simple elegant implementation lisp jvm 2010 promoted status adopt 2012 growing number unofficial experimental implementations platforms testify popularity language tooling clojure development seen significant improvement years following list popular ides/editors plug-ins combined provide excellent support clojure development addition tools provided community official clojure cli tools ref name= guides/deps_and_cli /ref also become available gnu/linux macos windows since clojure 1.9 following examples run clojure repl one started clojure cli tools online repl one available repl.it strong emphasis simplicity typical clojure programs consist mostly functions simple data structures i.e. lists vectors maps sets like lisps one iconic features clojure interactive programming repl note following examples codice_2 starts line comment codice_3 indicates output unlike runtime environments names get compiled away clojure runtime environment easily introspectable using normal clojure data structures similar lisps clojure homoiconic also known code data example see easy write code modifies code threading macros codice_4 codice_5 friends syntactically express abstraction piping collection data series transformations also achieved efficiently using transducers thread-safe generator unique serial numbers though like many lisp dialects clojure built-in codice_6 function uses internally anonymous subclass codice_7 n't write anything macro using silence prints within clojure created ground embrace host platforms one design goals thus provides excellent language interoperability java 10 threads manipulating one shared data structure consists 100 vectors one containing 10 initially sequential unique numbers thread repeatedly selects two random positions two random vectors swaps changes vectors occur transactions making use clojure software transactional memory system
|
Programming language topics
|
expect expect extension tcl scripting language written libes program automates interactions programs expose text terminal interface expect originally written 1990 unix platform since become available microsoft windows systems expect used automate control interactive applications telnet ftp passwd fsck rlogin tip ssh others expect uses pseudo terminals unix emulates console windows starts target program communicates human would via terminal console interface tk another tcl extension used provide gui expect serves glue link existing utilities together general idea figure make expect use system existing tools rather figure solve problem inside expect key usage expect involves commercial software products many products provide type command-line interface usually lack power needed write scripts built service users administering product company often spend resources fully implement robust scripting language expect script spawn shell look environmental variables perform unix commands retrieve information enter product command-line interface armed necessary information achieve user goal retrieving information interacting product via command-line interface script make intelligent decisions action take every time expect operation completed results stored local variable called expect_out allows script harvest information feedback user also allows conditional behavior send next based circumstances common use expect set testing suite whether programs utilities embedded systems dejagnu testing suite written using expect use testing used extensively testing gcc well suited testing remote targets embedded development one automate generation expect script using tool called 'autoexpect tool observes actions generates expect script using heuristics though generated code may large somewhat cryptic one always tweak generated script get exact code spawn telnet remote_server expect username send my_user_id\r expect password send my_password\r expect send my_command\r expect set results expect_out buffer send exit\r expect eof another example script automates ftp set timeout -1 spawn ftp remote_server expect username send my_user_id\r expect password send my_password\r expect ftp send bin\r expect ftp send prompt\r expect ftp send mget *\r expect ftp send bye\r expect eof example automates sftp password proc connect passw set user lindex argv 0 set passw lindex argv 1 set host lindex argv 2 set location lindex argv 3 set file1 lindex argv 4 set file2 lindex argv 5 user == || passw == || host == || location == || file1 == || file2 == spawn sftp user host set rez connect passw rez == 0 puts \nerror connecting server host user user password passw \n exit 1 using passwords command-line arguments like example huge security hole user machine read password running ps however add code prompt password rather giving password argument secure see example stty -echo send_user -- enter password expect_user -re \n send_user \n stty echo set pass expect_out 1 string another example automated ssh login user machine set timeout 60 spawn ssh user machine 1 wait close spawn_id various projects implement expect-like functionality languages c java scala groovy perl python ruby shell go generally exact clones original expect concepts tend similar
|
Programming language topics
|
mlisp mlisp variant lisp algol-like syntax based m-expressions function syntax original description lisp john mccarthy mccarthy m-expressions never implemented mlisp first implemented ibm 360 horace enea reimplemented pdp 10 david canfield smith second implementation also supported special kind lambdas fexpr evaluate arguments lisp-1 scheme single namespace variables functions mlisp preprocessor alternative reader-friendly syntax lisp descendant mlisp 2 introduced new concepts mlisp2 called transitional language authors larry tesler improved pattern matching system implement successor language called lisp70 completed preliminary version though path lisp evolution widely neglected resembles features later found ml scheme m-lisp second branch—independent mlisp approach— described author essentially hybrid m-expression lisp scheme multiple third-party implementations infix-notation lisps lisp-like lisp-derived languages notable examples include
|
Programming language topics
|
data store data store repository persistently storing managing collections data include repositories like databases also simpler store types simple files emails etc database series bytes managed database management system dbms file series bytes managed file system thus database file series bytes stored called data store matlab cloud storage systems like vmware firefox os use datastore term abstracting collections data inside respective applications data store refer broad class storage systems including
|
Databases
|
test register test register intel 80386 intel 80486 processor register used processor usually self-test registers undocumented used specialized software test registers named tr3 tr7 regular programs n't usually require registers work pentium test registers replaced variety model-specific registers msrs two test registers tr6 tr7 provided purpose testing tr6 test command register tr7 test data register registers accessed variants mov instruction test register may either source operand destination operand mov instructions defined real-address mode protected mode test registers privileged resources protected mode mov instructions access executed privilege level 0 attempt read write test registers executing privilege level causes general protection exception also instructions generate invalid opcode exception cpu newer 80486
|
Computer architecture
|
lunix lunix short little unix unix-like multi-tasking operating system designed run natively commodore 64 commodore 128 home computer systems supports tcp/ip networking slip ppp using rs232 interface unlike unix-like systems lunix written 6502 assembly language instead c. first version lunix released 1993 current version 0.21 dates 2004 amongst others supports preemptive multitasking unix pipes variety protocols like tcp/ip slip ppp rs232 dynamic memory management virtual consoles contains web server clients telnet pop3 ftp act terminal terminal server rs232 lunix developed daniel dallmann contributed ilker ficicilar stefan haubenthal paul gardner-stephen late 1990s first generation lunix support faster rs232 via clever software tricks 80 column vic vdc screen support ps/2 keyboard support small set standard unix commands possible first distribution attach two keyboards two monitors one rs232 terminal set three simultaneous multitasking sessions c128 lunix also supports 2 mhz mode boot disk convenience c128 platform lunix came extensive documentation time well-defined library calls relocatable code support decent memory management functions made possible develop software lunix easily
|
Operating systems
|
sound object sndobj library sound object sndobj library c++ object-oriented programming library music audio development composed 100+ classes signal processing audio midi file i/o available cross-platform linux windows mac os x irix unix-like systems library development cooperative project hosted sourceforge new versions released twice-yearly development versions available via concurrent versions system cvs library also provides bindings python aka pysndobj java common lisp cffi
|
Programming language topics
|
widen company widen software company founded 1948 plate-engraving business developed digital print company eventually software company company founded 1948 eponymous emily arthur widen private plate engraving business focused newspaper presses 1985 company began focusing color printing scanning mid-1990s widen began investing digital printing services well software services internet developing image database system saas digital asset management company company changed name widen colourgraphics ltd. widen enterprises 1997 company headquartered monona wisconsin ranked comparably one top smes united states terms management widen ’ ceo matthew gonnering though company renamed position chief eudaimonia officer reflect philosophy management style appointed 2009 transitioned company largely prepress printing company software firm widen software focuses digital asset management houses corporate information helps develop digital projects like websites advertising cataloguing example widen ’ cloud software hosts corporate information companies like brooks running shoes widen provides services public services private companies
|
Distributed computing architecture
|
mordechai ben-ari mordechai moti ben-ari professor computer science education weizmann institute science ben-ari published numerous textbooks computer science developed software tools teaching computer science written many influential papers computer science education primary focus books tools learning theoretical concepts computer science concurrency mathematical logic collaboration university joensuu finland group developed jeliot program animation system teaching elementary computer science programming ben-ari received 2004 acm sigcse award outstanding contributions computer science education named acm distinguished educator 2009
|
Programming language topics
|
call stack computer science call stack stack data structure stores information active subroutines computer program kind stack also known execution stack program stack control stack run-time stack machine stack often shortened stack although maintenance call stack important proper functioning software details normally hidden automatic high-level programming languages many computer instruction sets provide special instructions manipulating stacks call stack used several related purposes main reason one keep track point active subroutine return control finishes executing active subroutine one called yet complete execution control handed back point call activations subroutines may nested level recursive special case hence stack structure example subroutine codice_1 calls subroutine codice_2 four different places codice_2 must know return execution completes accomplish address following instruction jumps codice_2 return address pushed onto call stack call since call stack organized stack caller pushes return address onto stack called subroutine finishes pulls pops return address call stack transfers control address called subroutine calls yet another subroutine push another return address onto call stack information stacking unstacking program dictates pushing consumes space allocated call stack error called stack overflow occurs generally causing program crash adding subroutine entry call stack sometimes called winding conversely removing entries unwinding usually exactly one call stack associated running program accurately task thread process although additional stacks may created signal handling cooperative multitasking setcontext since one important context referred stack implicitly task however forth programming language data stack parameter stack accessed explicitly call stack commonly referred stack see high-level programming languages specifics call stack usually hidden programmer given access set functions memory stack example abstraction assembly languages hand require programmers involved manipulating stack actual details stack programming language depend upon compiler operating system available instruction set noted primary purpose call stack store return addresses subroutine called location address instruction calling routine later resume needs saved somewhere using stack save return address important advantages alternative calling conventions one task stack thus subroutine thread-safe active simultaneously different tasks different things another benefit providing reentrancy recursion automatically supported function calls recursively return address needs stored activation function later used return function activation stack structures provide capability automatically depending language operating-system machine environment call stack may serve additional purposes including example typical call stack used return address locals parameters known call frame environments may fewer functions assigned call stack forth programming language example ordinarily return address counted loop parameters indexes possibly local variables stored call stack environment named return stack although data temporarily placed using special return-stack handling code long needs calls returns respected parameters ordinarily stored separate data stack parameter stack typically called stack forth terminology even though call stack since usually accessed explicitly forths also third stack floating-point parameters call stack composed stack frames also called activation records activation frames machine dependent abi-dependent data structures containing subroutine state information stack frame corresponds call subroutine yet terminated return example subroutine named codice_2 currently running called subroutine codice_1 top part call stack might laid like adjacent picture diagram like drawn either direction long placement top direction stack growth understood furthermore independently architectures differ whether call stacks grow towards higher addresses towards lower addresses logic diagram independent addressing choice stack frame top stack currently executing routine stack frame usually includes least following items push order stack frame sizes differ different functions invocations particular function popping frame stack constitute fixed decrement stack pointer function return stack pointer instead restored frame pointer value stack pointer function called stack frame contains stack pointer top frame immediately stack pointer mutable register shared invocations frame pointer given invocation function copy stack pointer function invoked locations fields frame defined relative either top frame negative offsets stack pointer relative top frame positive offsets frame pointer location frame pointer must inherently defined negative offset stack pointer systems stack frame field contain previous value frame pointer register value caller executing example stack frame codice_2 would memory location holding frame pointer value codice_1 uses shown diagram value saved upon entry subroutine restored upon return field known location stack frame enables code access frame successively underneath currently executing routine frame also allows routine easily restore frame pointer caller frame returns programming languages support nested subroutines also field call frame points stack frame latest activation procedure closely encapsulates callee i.e immediate scope callee called access link static link keeps track static nesting dynamic recursive calls provides routine well routines may invoke access local data encapsulating routines every nesting level architectures compilers optimization cases store one link enclosing level immediately enclosing deeply nested routines access shallow data traverse several links strategy often called display access links optimized away inner function access non-constant local data encapsulation case pure functions communicating via arguments return values example historical computers burroughs large systems special display registers support nested functions compilers modern machines ubiquitous x86 simply reserve words stack pointers needed purposes stack frame subroutine caller considered overlap overlap consisting area parameters passed caller callee environments caller pushes argument onto stack thus extending stack frame invokes callee environments caller preallocated area top stack frame hold arguments supplies subroutines calls area sometimes termed outgoing arguments area callout area approach size area calculated compiler largest needed called subroutine usually call stack manipulation needed site call subroutine minimal good since many call sites subroutine called values actual arguments evaluated call site since specific particular call either pushed onto stack placed registers determined used calling convention actual call instruction branch link typically executed transfer control code target subroutine called subroutine first code executed usually termed subroutine prologue since necessary housekeeping code statements routine begun instruction set architectures instruction used call subroutine puts return address register rather pushing onto stack prologue commonly save return address pushing value onto call stack although called subroutine call routines may leave value register similarly current stack pointer and/or frame pointer values may pushed frame pointers used prologue typically set new value frame pointer register stack pointer space stack local variables allocated incrementally changing stack pointer forth programming language allows explicit winding call stack called return stack subroutine ready return executes epilogue undoes steps prologue typically restore saved register values frame pointer value stack frame pop entire stack frame stack changing stack pointer value finally branch instruction return address many calling conventions items popped stack epilogue include original argument values case usually stack manipulations need done caller calling conventions however caller responsibility remove arguments stack return returning called function pop top frame stack perhaps leaving return value general act popping one frames stack resume execution elsewhere program called stack unwinding must performed non-local control structures used used exception handling case stack frame function contains one entries specifying exception handlers exception thrown stack unwound handler found prepared handle catch type thrown exception languages control structures require general unwinding pascal allows global goto statement transfer control nested function previously invoked outer function operation requires stack unwound removing many stack frames necessary restore proper context transfer control target statement within enclosing outer function similarly c codice_11 codice_12 functions act non-local gotos common lisp allows control happens stack unwound using codice_13 special operator applying continuation stack logically unwound rewound stack continuation way implement continuations example using multiple explicit stacks application continuation simply activate stack wind value passed scheme programming language allows arbitrary thunks executed specified points unwinding rewinding control stack continuation invoked call stack sometimes inspected program running depending program written compiled information stack used determine intermediate values function call traces used generate fine-grained automated tests cases like ruby smalltalk implement first-class continuations example gnu debugger gdb implements interactive inspection call stack running paused c program taking regular-time samples call stack useful profiling performance programs subroutine pointer appears call stack sampling data many times likely code bottleneck inspected performance problems language free pointers non-checked array writes c mixing control flow data affects execution code return addresses saved frame pointers simple program data parameters return values call stack security risk possibly exploitable stack buffer overflows common type buffer overflows one attacks involves filling one buffer arbitrary executable code overflowing buffer overwrite return address value points directly executable code result function returns computer executes code kind attack easily blocked w^x similar attacks succeed even w^x protection enabled including return-to-libc attack attacks coming return-oriented programming various mitigations proposed storing arrays completely separate location return stack case forth programming language
|
Operating systems
|
bare machine computer science bare machine bare metal refers computer executing instructions directly logic hardware without intervening operating system modern operating systems evolved various stages elementary present day complex highly sensitive systems incorporating many services development programmable computers require physical changes run different programs prior development operating systems sequential instructions executed computer hardware directly using machine language without system software layer approach termed bare machine precursor modern operating systems today mostly applicable embedded systems firmware generally time-critical latency requirements conventional programs run runtime system overlaid operating system pdp-11 machine allowed programmers load program supplied machine code ram resulting operation program could monitored lights output derived mag tape print devices storage bare machine programming remains common practice embedded systems microcontrollers microprocessors often boot directly monolithic single-purpose software without loading separate operating system embedded software vary structure simplest form may consist infinite main loop calling subroutines responsible checking inputs performing actions writing outputs
|
Operating systems
|
gamebike game bike interactive fitness bike requires user exercise order play video games user must pedal bike order character accelerate must turn handlebars steer game bike allows users control character game getting exercise game bike name interactive fitness device first invented patented edward h. ted parks m.d 2000 dr parks sold rights patent cateye co ltd japanese company expertise electronic bicycle accessories bike lights speedometers cateye initial embodiment parks design used traditional bicycle attached referred gb100 system front tire placed turn style platform used read direction sensors placed rear wheel mounted bicycle trainer measure speed cateye co ltd. first started production game bike gb100 form project handled group new jersey redesigned product single package incorporated stand-alone indoor exercise bike gb200 born immediate need commercial version soon covered introduction popular gb-300 game bike late 2008 cateye co ltd. stopped international distribution fitness line game bike production done source distributors inc. dallas texas source distributors produced bike made modifications unit improve controller serviceability game bike popular product within school ymca markets thousands bikes sold since start 2003 game bike owned hudson fitness llc game bike currently available hudson fitness llc continues supporting game bike service compatible titles include speed-based video game ps2/ps3/game cube/xbox
|
Computer architecture
|
mk-dos mk-dos one widespread operating systems elektronika bk personal computers developed mikhail korolev dmitriy butyrskiy 1in like andos system provided full compatibility models emulating bk-0010 environments modern bk-0011 bk-0011m machines program requests magnetic tape made proper rom functions redirected disk system supported 4 physical disk drives actual number limited disk rom installed many hard disk partitions number letters latin alphabet could used separate logical drives volume 32 mb see also drive letter assignment starting version 3.0 system also supported mounting disk images logical drives booted bk-0011 bk-0011m system automatically created ram disk computer memory widespread file system along mk-dos users microdos support file fragmentation like file system used rt-11 required frequent spatial reallocation maintain optimum contiguous free space rt-11 users would use 'squeeze command worked way *compact command acorn dfs bbc micro although mk-dos incompatible rt-11 file system shared many principles microdos file system read-only support andos filename length limited 14 symbols filename extension recognized separately considered part filename minimal installation system took little 8 kb computer memory functional norton commander-like file manager called mcommander also shipped number utilities including drivers rt-11 fat12 csi-dos file systems add-ons file manager
|
Operating systems
|
stxit stxit macro instruction dos/360 operating system ibm system/360 series mainframe computers successors later mainframe series also available univac series 90 mainframes running tos/dos operating system later vs/9 operating system macro abbreviation term set exit used programs written assembly language used create recovery routine event program errors similar signal handlers c try/finally blocks c++ java object oriented languages stxit macro would provide error recovery address several major types errors certain operator signals errors covered depended upon operating system general errors provided recovery included timer interrupt stxit provided mechanism sampling program execution used various legacy performance analyzers essentially psw gathered time interval used later analysis determine hot spots program check stxit provided mechanism program animation via deliberate introduction invalid opcodes fly locations target programs exit recovery entered original opcode would restored ready later resumption new location set format macro call depended upon system used upon dos/vse one two forms either macro call establish create stxit routine handle appropriate event macro call de-establish longer handle event establish stxit routine would code stxit routine completes returns point invoked via exit macro return appropriate point called unless ab routine case permitted return must issue termination macro eoj cancel detach dump de-establish cancel stxit routine would code cancel routine event everything beginning one space parameter comment z/system vse stxit functions provided previously ibm dos/vse still supported addition new stxit macro function 'disabled timer appendage die available use supervisor mode key 0 psw privilege bit =1 format die means routine handle disabled interval timer event rtnaddr address handle expiration interval timer set tod event coded address may instead specified 1 meaning address stored register 1 routine subject strict restrictions including changing register contents using svcs univac vs/9 stxit macro vs/9 parameter based missing entries entered commas e.g third item handled format would remove one handlers stxit macro re-invoked blank entry handlers removed one stxit macro call effect time class event handled omitted would two commas row indicate unhandled class event causes error handled operating system default handler events representing critical errors abend progcheck program terminated eo79 error user option request pdump non-critical events event ignored later error recovery systems would provide specifying errors explicitly opposed position parameter stxit macro univac vs/9 continued support stxit also added crtn contingency routine macro provide even powerful error recovery well recovery errors stxit capture originally crtn stxit could used together later releases operating system provided crtn stxit macro used crtn handled events covered stxit used cover event stxit routine handled event crtn routine invoked
|
Operating systems
|
mausezahn typical applications mausezahn include mausezahn allows sending arbitrary sequence bytes directly network interface card integrated packet builder provides simple command line interface complicated packets since version 0.38 mausezahn offers multi-threaded mode cisco-style command line interface version 0.38 mausezahn supports following features mausezahn sends exactly packet user specified therefore rather less suited vulnerability audits additional algorithms required detect open ports behind firewall automatically evade intrusion detection systems ids however network administrator could implement audit routines via script utilizes mausezahn creating actual packets mausezahn currently runs linux systems plans port windows operating system
|
Computer security
|
aos/vs ii aos/vs ii discontinued operating system data general 32-bit mv/eclipse computers aos/vs ii operating system released 1988 originally simply rev 8.00 aos/vs operating system however introduced new file system compatible original aos aos/vs file system also contained new features like access control list acl groups since customers want upgrade new file system invest new hardware data general agreed continue bug-fix support “ immortal ” revision aos/vs became known colloquially aos/vs “ classic ” new development would proceed aos/vs ii revision numbers rolled back 1.00 vs-classic rev 7.7x vs-ii rev 3.2x updated survive year 2000 problem although time obsolescent among new features part aos/vs ii full tcp/ip stack nfs support expanded kernel address space using ring-1 logical disk-level user data cache /vs classic file system metadata cache user data cache
|
Operating systems
|
apache cassandra apache cassandra free open-source distributed wide column store nosql database management system designed handle large amounts data across many commodity servers providing high availability single point failure cassandra offers robust support clusters spanning multiple datacenters asynchronous masterless replication allowing low latency operations clients avinash lakshman one authors amazon dynamo prashant malik initially developed cassandra facebook power facebook inbox search feature facebook released cassandra open-source project google code july 2008 march 2009 became apache incubator project february 17 2010 graduated top-level project facebook developers named database trojan mythological prophet cassandra classical allusions curse oracle releases graduation include cassandra introduced cassandra query language cql cql simple interface accessing cassandra alternative traditional structured query language sql cql adds abstraction layer hides implementation details structure provides native syntaxes collections common encodings language drivers available java jdbc python dbapi2 node.js helenus go gocql c++ example keyspace creation including column family cql 3.0 gives cassandra 1.0 cassandra row level consistent meaning inserts updates table affect row processed approximately time may affect non-key columns inconsistent ways one update may affect one column another affects resulting sets values within row never specified intended cassandra 1.1 solved issue introducing row-level isolation tombstones known cause performance degradation severe consequence levels cassandra wide column store essentially hybrid key-value tabular database management system data model partitioned row store tunable consistency rows organized tables first component table primary key partition key within partition rows clustered remaining columns key columns may indexed separately primary key tables may created dropped altered run-time without blocking updates queries cassandra joins subqueries rather cassandra emphasizes denormalization features like collections column family called table since cql 3 resembles table rdbms relational database management system column families contain rows columns row uniquely identified row key row multiple columns name value timestamp unlike table rdbms different rows column family share set columns column may added one multiple rows time key cassandra corresponds value object key values columns columns grouped together sets called column families thus key identifies row variable number elements column families could considered tables table cassandra distributed multi dimensional map indexed key furthermore applications specify sort order columns within super column simple column family cassandra java-based system managed monitored via java management extensions jmx jmx-compliant nodetool utility instance used manage cassandra cluster adding nodes ring draining nodes decommissioning nodes nodetool also offers number commands return cassandra metrics pertaining disk usage latency compaction garbage collection since cassandra 2.0.2 2013 measures several metrics produced via dropwizard metrics framework may queried via jmx using tools jconsole passed external monitoring systems via dropwizard-compatible reporter plugins according db-engines ranking cassandra popular wide column store september 2014 became 9th popular database
|
Databases
|
adobe coldfusion adobe coldfusion commercial rapid web-application development platform created j. j. allaire 1995 programming language used platform also commonly called coldfusion though accurately known cfml coldfusion originally designed make easier connect simple html pages database version 2 1996 became full platform included ide addition full scripting language one distinguishing features coldfusion associated scripting language coldfusion markup language cfml cfml compares scripting components asp jsp php purpose features tag syntax closely resembles html script syntax resembles javascript coldfusion often used synonymously cfml additional cfml application servers besides coldfusion coldfusion supports programming languages cfml server-side actionscript embedded scripts written javascript-like language known cfscript originally product allaire released july 2 1995 coldfusion developed brothers joseph j. allaire jeremy allaire 2001 allaire acquired macromedia turn acquired adobe systems inc 2005 coldfusion often used data-driven websites intranets also used generate remote services rest services websockets soap web services flash remoting especially well-suited server-side technology client-side ajax coldfusion also handle asynchronous events sms instant messaging via gateway interface available coldfusion mx 7 enterprise edition coldfusion provides number additional features box main features include implementations cfml offer similar enhanced functionality running .net environment image manipulation engine written c featured among things built-in scripting language cfscript plugin modules written java syntax similar html equivalent html element coldfusion tag begins letters cf followed name indicative tag interpreted html e.g cfoutput begin output variables content addition cfscript plugins described cfstudio provided design platform wysiwyg display addition coldfusion cfstudio also supports syntax languages popular backend programming perl addition making backend functionality easily available non-programmer version 4.0 forward particular integrated easily apache web server internet information services versions coldfusion prior 6.0 written using microsoft visual c++ meant coldfusion largely limited running microsoft windows although allaire successfully port coldfusion sun solaris starting version 3.1 allaire company sold macromedia macromedia sold adobe earlier versions robust versions available version 4.0 forward release coldfusion mx 6.0 engine re-written java supported runtime environment easily replaced configuration options runtime environment sun version 6.1 included ability code debug shockwave flash version 3.1 brought port sun solaris operating system cold fusion studio gained live page preview html syntax checker cold fusion moniker renamed simply coldfusion possibly distinguish cold fusion theory version 4.5 brought ability natively invoke java objects execute system commands talk directly java ee server first release macromedia allaire corporation acquisition last legacy coded specific platform january 16 2001 allaire announced pending merger macromedia macromedia continued development released product name coldfusion 5.0 retained name coldfusion remainder version 5 releases prior 2000 edwin smith allaire architect jrun later flash player initiated project codenamed neo project later revealed coldfusion server re-written completely using java made portability easier provided layer security server ran inside java runtime environment june 2002 macromedia released version 6.0 product slightly different name coldfusion mx allowing product associated macromedia brand original branding coldfusion mx completely rebuilt ground based java ee platform coldfusion mx also designed integrate well macromedia flash using flash remoting release coldfusion mx cfml language api released oop interface release coldfusion 7.0 february 7 2005 naming convention amended rendering product name macromedia coldfusion mx 7 codename cfmx7 blackstone cfmx 7 added flash-based xforms-based web forms report builder output adobe pdf well flashpaper rtf excel adobe pdf output also available wrapper html page converting page quality printable document enterprise edition also added gateways provide interaction non-http request services im services sms directory watchers asynchronous execution xml support boosted version include native schema checking coldfusion mx 7.0.1 codename merrimack added support mac os x improvements flash forms rtf support cfreport new cfcproxy feature java/cfc integration coldfusion mx 7.0.2 codenamed mystic included advanced features working adobe flex 2 well improvements cf report builder july 30 2007 adobe systems released coldfusion 8 dropping mx name beta testing codename used scorpio eighth sign zodiac eighth iteration coldfusion commercial product 14,000 developers worldwide active beta process many testers 5,000 adobe systems originally expected coldfusion development team consisted developers based newton/boston massachusetts offshore bangalore india new features cfpdfform tag enables integration adobe acrobat forms image manipulation functions microsoft .net integration cfpresentation tag allows creation dynamic presentations using adobe acrobat connect web-based collaboration solution formerly known macromedia breeze addition coldfusion administrator enterprise version ships built-in server monitoring coldfusion 8 available several operating systems including linux mac os x windows server 2003 additions coldfusion 8 built-in ajax widgets file archive manipulation cfzip microsoft exchange server integration cfexchange image manipulation including automatic captcha generation cfimage multi-threading per-application settings atom rss feeds reporting enhancements stronger encryption libraries array structure improvements improved database interaction extensive performance improvements pdf manipulation merging capabilities cfpdf interactive debugging embedded database support apache derby ecmascript compliant cfscript development coldfusion applications several tools available primarily adobe dreamweaver cs4 macromedia homesite 5.x cfeclipse eclipse others tag updaters available applications update support new coldfusion 8 features coldfusion 9 codenamed centaur released october 5 2009 new features cf9 include coldfusion 10 codenamed zeus released may 15 2012 new improved features available editions standard enterprise developer include limited additional new improved features coldfusion enterprise developer editions include limited lists obtained adobe web site pages describing new features listed first links following list cf10 originally referred codename zeus first confirmed coming adobe adobe max 2010 much prerelease period also commonly referred coldfusion next coldfusion x blogs twitter etc. adobe finally confirmed would coldfusion 10 much 2010 coldfusion product manager adam lehman toured us setting countless meetings customers developers user groups formulate master blueprint next feature set september 2010 presented plans adobe given full support approval upper management first public beta coldfusion 10 released via adobe labs 17 february 2012 coldfusion 11 codenamed splendor released april 29 2014 new improved features available editions standard enterprise developer include coldfusion 11 also removed many features previously identified simply deprecated longer supported earlier releases example cflog tag long offered date time attributes deprecated redundant date time always logged cf11 use would cause cflog tag fail adobe coldfusion 2016 release codenamed raijin also known generically coldfusion 2016 released february 16 2016 new improved features available editions standard enterprise developer include adobe coldfusion 2018 release known generically coldfusion 2018 released july 12 2018 coldfusion 2018 codenamed aether prerelease new improved features available editions standard enterprise developer include august 13 2012 adobe announced new roadmap coldfusion including code names splendor thunder dazzle next two release versions adobe announced new features coldfusion including limited mobile streamlined mobile application development revamped new pdf functionalities enabling enterprise easily integrate social media streams enterprise mobility support responsive multi screen content digital marketing – web mobile social analytics customizable enterprise video portal adobe also announced roadmap upcoming cloud enhancements roadmap projects coldfusion development year 2021 coldfusion generate pdf documents using standard html i.e additional coding needed generate documents print cfml authors place html css within pair cfdocument tags new coldfusion 11 cfhtmltopdf tags generated document either saved disk sent client browser coldfusion 8 introduced also cfpdf tag allow control pdf documents including pdf forms merging pdfs tags however use adobe pdf engine cfdocument uses combination commercial jpedal java pdf library free open source java library itext cfhtmltopdf uses embedded webkit implementation coldfusion originally object-oriented programming language like php versions 3 coldfusion falls category oo languages support multiple inheritance along java smalltalk etc. mx release 6+ coldfusion introduced basic oo functionality component language construct resembles classes oo languages component may contain number properties methods one component may also extend another inheritance components support single inheritance object handling feature set performance enhancing occurred subsequent releases release coldfusion 8 java-style interfaces supported coldfusion components use file extension cfc differentiate coldfusion templates .cfm component methods may made available web services additional coding configuration required method access declared 'remote coldfusion automatically generates wsdl url component manner nowiki http //path/to/components/component.cfc wsdl /nowiki aside soap services offered flash remoting binary format methods declared remote may also invoked via http get post request consider get request shown br invoke component search function passing query strict arguments type invocation well-suited ajax-enabled applications coldfusion 8 introduced ability serialize coldfusion data structures json consumption client coldfusion server automatically generate documentation component navigate url insert appropriate code within component declarations application component introspection available developers coldfusion components access component documentation requires password developer view documentation components known coldfusion server navigating coldfusion url interface resembles javadoc html documentation java classes coldfusion provides several ways implement custom markup language tags i.e included core coldfusion language especially useful providing familiar interface web designers content authors familiar html imperative programming traditional common way using cfml standard cfml page interpreted tag tag name corresponding file name prefixed cf_ example file imap.cfm used tag cf_imap attributes used within tag available attributes scope tag implementation page cfml pages accessible directory calling page via special directory coldfusion web application via cfimport tag calling page latter method necessarily require cf_ prefix tag name second way developments cfx tags using java c++ cfx tags prefixed cfx_ example cfx_imap tags added coldfusion runtime environment using coldfusion administrator jar dll files registered custom tags finally coldfusion supports jsp tag libraries jsp 2.0 language specification jsp tags included cfml pages using cfimport tag standard coldfusion installation allows deployment coldfusion war file ear file deployment standalone application servers macromedia jrun ibm websphere coldfusion also deployed servlet containers apache tomcat mortbay jetty platforms officially support coldfusion leave many features inaccessible coldfusion 10 macromedia jrun replaced apache tomcat coldfusion java ee application coldfusion code mixed java classes create variety applications use existing java libraries coldfusion access underlying java classes supports jsp custom tag libraries access jsp functions retrieving jsp page context getpagecontext prior coldfusion 7.0.1 coldfusion components could used java .net declaring web services however beginning coldfusion mx 7.0.1 coldfusion components used directly within java classes using cfcproxy class recently much interest java development using alternate languages jython groovy jruby coldfusion one first scripting platforms allow style java development coldfusion 8 natively supports .net within cfml syntax coldfusion developers simply call .net assembly without needing recompile alter assemblies way data types automatically translated coldfusion .net example .net datatable → coldfusion query unique feature java ee vendor coldfusion 8 offers ability access .net assemblies remotely proxy without use .net remoting allows coldfusion users leverage .net without installed windows operating system acronym coldfusion markup language cfml coldfusion templates saved disk traditionally given extension .cfm .cfml .cfc extension used coldfusion components original extension dbm dbml stood database markup language talking coldfusion users use acronym cf used numerous coldfusion resources user groups cfugs sites cfmx common abbreviation coldfusion versions 6 7 a.k.a coldfusion mx coldfusion originated proprietary technology based web technology industry standards however becoming less closed technology availability competing products alternative products include alphabetical order argument made coldfusion even less platform-bound raw java ee .net simply coldfusion run top .net app server new atlanta top servlet container java ee application server jrun websphere jboss geronimo tomcat resin server jetty web server etc. theory coldfusion application could moved unchanged java ee application server .net application server march 2013 known issue affecting coldfusion 8 9 10 left national vulnerability database open attack vulnerability identified patch released adobe cf9 cf10 january april 2013 coldfusion vulnerability blamed linode intrusion linode manager control panel website security bulletin hotfix issued adobe week earlier may 2013 adobe identified another critical vulnerability reportedly already exploited wild targets recent versions coldfusion servers web-based administrator api locked vulnerability allows unauthorized users upload malicious scripts potentially gain full control server security bulletin hotfix issued adobe 6 days later april 2015 reported cross-site scripting xss vulnerability adobe coldfusion 10 update 16 coldfusion 11 update 5 allowed remote attackers inject arbitrary web script html however exploitable users authenticated administration panel
|
Programming language topics
|
adaptive domain environment operating systems adeos adaptive domain environment operating systems nanokernel hardware abstraction layer hal hypervisor operates computer hardware operating system runs distinct nanokernels low level layer outer kernel instead intended run several kernels together makes similar virtualization technologies adeos provides flexible environment sharing hardware resources among multiple operating systems among multiple instances single os thereby enabling multiple prioritized domains exist simultaneously hardware adeos successfully inserted beneath linux kernel opening range possibilities smp clustering efficient virtualization patchless kernel debugging real-time systems linux unusually among hals adeos loaded linux loadable kernel module allow another os run along fact adeos developed context rtai real-time application interface modularize separate hal real-time kernel two categories existing solutions enable multiple operating systems run system first simulation-based provides virtual environment run additional operating systems second suggests usage nanokernel layer enable hardware sharing simulation category tools vmware plex86 virtualpc simos also kvm similar adeos rt requires specific virtualization hardware support solutions used users desire run applications foreign base os provide control whatsoever base os user simulation never meant used production environment nanokernel category tools space cache kernel exokernel suggest building miniature hardware management facilities thereafter used build production operating systems problem approach address issue currently existing operating systems user base adeos addresses requirements categories application providing simple layer inserted unmodified running os thereafter provides required primitives mechanisms allow multiple oses share hardware environment adeos attempt impose restrictions hardware ’ usage different oses necessary adeos ’ operation instead actual restriction imposed system administrator system programmer exposes system mismanagement idea behind adeos give back control system administrators programmers adeos implements queue signals time peripheral sends signal different operating systems running machine awakened turn must decide accept handle ignore discard terminate signal signals handled discarded os passed next os chain signals terminated propagated latter stages adeos ensure equal trusted access hardware takes control hardware commands issued different oses also must intrude much different oses ’ normal behavior os encompassed domain total control domain may include private address space software abstractions process virtual memory file-systems etc adeos attempt impose policy usage hardware except needed survival task determining policy left system architect adeos uses interrupt pipe propagate interrupts different domains running hardware domains may prefer first receive hardware interrupts adeos provides mechanism domains access priority interrupt dispatching effect adeos places requesting domain interrupt handler accompanying tables may called interrupt mechanism space terminology first stages interrupt pipeline domains control whether accept ignore discard terminate interrupts different effect controlled differently accepting interrupts normal state domain interrupt mechanism adeos encounters domain accepting interrupts summons interrupt handler set required cpu environment stack content interrupt handler operate correctly os may decide operate number operations including task scheduling os done pipeline proceeds planned propagating interrupts pipeline os domain want interrupted reason asks adeos stall stage domain occupies interrupt pipeline interrupts go pipeline stalled stage occupied domain os done wanting uninterrupted asks adeos install pipeline thereafter interrupts stalled corresponding stage follow route stages pipeline domain discarding interrupts interrupt passes stage occupied domain continues onto stages domain terminates interrupts interrupts terminated propagated latter stages interrupt discarding termination possible os domain recognizes adeos since oses recognize adeos possible create domain serves handler os hence interrupt pipeline stage always precedes handled domain stage may take actions domain adeos order provide handled domain os illusion normal system operation adeos done traversing pipeline checks domains dormant case calls idle task task remains active occurrence next interrupt domains n't dormant restores processor state prior interrupt entering pipeline execution continues left since adeos much hardware dependent many details specific one particular implementations general-purpose operating system resource sharing one main objectives adeos provide environment enables multiple general purpose oses share hardware developing oses usually complicated process sometimes requires extra hardware in-circuit emulators probe hardware os running using adeos os development eased since undesired behavior may controlled appropriate domain handler also provide default domain handler os development developers may controlled direct access hardware meant control adeos kernel-module development domain handlers may developed independently adeos adeos provides way kernel debuggers probers take control linux without modifying linux adeos domains facilities would load normal kernel modules would thereafter request ring-zero domain adeos done may request priority interrupt dispatching interrupt pipeline hence linux gets handle interrupts able intercept interrupts carry requested debugging tasks also extended performance profilers development tools
|
Computer architecture
|
nedi nedi open source software tool discovers maps inventories network devices tracks connected end-nodes contains lot features user-friendly gui managing enterprise networks example mac address mapping/tracking traffic error graphing uptime monitoring correlate collected syslog trap messages customizable notification drawing network maps extensive reporting features device software poe usage disabled interfaces link errors switch usage many modular architecture allows simple integration tools example cacti graphs created purely based discovered information due nedi versatility things like printer resources monitored well development started 2001 paul scherrer institute remo rickli released public gpl2 2003 next decade nedi grew reasonable network management suite help community partners 2014 remo rickli founded nedi consulting providing commercial support development around nedi since major update released every year e.g 1.5 2015 access latest version bought support yearly subscription basis last year version released public gpl3 premium modules included free community edition
|
Computer security
|
ibm blu acceleration ibm blu acceleration collection technologies ibm research development labs analytical database workloads blu acceleration integrates number different technologies including in-memory processing columnar data actionable compression uses approximate huffman encoding compress pack data tightly cpu acceleration exploits simd technology provides parallel vector processing data skipping allows data use current active workload ignored term ‘ blu ’ stand anything particular however indirect play ibm traditional corporate nickname big blue ten ibm research development facilities around world filed 25 patents working blink ultra project resulted blu acceleration blu acceleration require indexes aggregates tuning blu acceleration integrated version 10.5 ibm db2 linux unix windows db2 luw uses storage memory constructs i.e. storage groups table spaces buffer pools sql language interfaces administration tools traditional db2 luw databases blu acceleration available ibm power x86 processor architectures blu acceleration second generation technology originated blink project started ibm almaden research center 2006 aimed primarily read-mostly business intelligence bi query processing blink combined scale-out multi-core processors dynamic random-access memory dram store copy data mart completely memory also used proprietary compression techniques algorithms allowed sql queries performed directly compressed data opposed requiring data decompressed processing could take place eventually blink incorporated two ibm products ibm smart analytics optimizer db2 z/os mainframe version db2 released november 2010 informix warehouse accelerator released march 2011 blu acceleration optimized accessing data ram however even data size grows extent longer fits ram intermediate results may spill disk blu acceleration perfected integrated db2 collaboration db2 product development ibm systems optimization competency center ibm research—this collaboration resulted addition columnar processing broader sql support i/o cpu efficiencies integration db2 sql compiler query optimizer storage layer four main advances part blu acceleration design blu acceleration optimized accessing data ram however even data size grows extent longer fits ram intermediate results may spill disk order-preserving frequency-based compression referred actionable compression blu acceleration allows wide variety comparative operations performed without decompression—and efficient use cpu memory cache registers actionable compression values appear frequently compressed higher level values appear less often actionable compression uses entropy encoding algorithm lossless data compression developed david a. huffman ph.d. student mit base offset coding another compression optimization technique used blu acceleration offset coding useful numeric data instead trying compress values 100 101 102 103 example db2 store single value 100 offsets value 1 2 3 etc. similar way db2 compresses index record ids rids —one three autonomic index compression algorithms db2 dynamically apply indexes blu acceleration values compressed order preserved means compared compressed.this allows common comparisons sql predicates performed encoded values without needing decompress data thereby accelerating evaluations reducing memory requirements lowering processing needs queries runtime. encoded data packed tightly possible collection bits equal register width cpu server used results fewer i/os data smaller better memory utilization data stored memory fewer cpu cycles data register aligned data skipping enables db2 detect ranges column values needed satisfy query avoid reading pages containing values disk data skipping utilizes secondary object called synopsis table tiny column-organized table created maintained automatically blu acceleration keeps metadata describes minimum maximum range data values chunks data 1,000 records table metadata automatically maintained insert update delete operations allows db2 blu acceleration automatically detect large sections data needed query processing effectively ignore conceptually blu acceleration ‘ data skipping similar zone map technology found puredata system analytics family however unlike zone maps metadata stored synopsis table ‘ tied particular page extent boundary―instead ‘ tied specific chunk data records data skipping deliver order magnitude savings across compute resources cpu ram i/o blu acceleration takes advantage single instruction multiple data simd processing available hardware used exploiting simd instructions low-level specific cpu instructions blu acceleration perform operation multiple points data simultaneously consequently db2 blu acceleration use single simd instruction get results multiple data elements example perform equality predicate processing —provided register db2 also put 128 bits simd register evaluate data single instruction level performance achieved ultimately determined hardware resources blu acceleration work said even server ‘ simd enabled blu acceleration emulate simd hardware smid software using bitmasking achieve parallelism deliver benefits simd offer addition blu acceleration engineered majority memory access occurs cpu cache accessing data ram operating almost exclusively data cpu cache ram blu acceleration minimizes latency able keep cpus busy designed process data substantially larger memory in-memory speeds blu acceleration prefetches streams data processing engine—advancing beyond system memory in-cpu memory optimization uses specialized in-memory optimized columnar prefetching algorithm determine milliseconds advance data loaded ram every algorithm designed minimize access ram maximize processing time l3 l2 caches order magnitude faster ram.
|
Databases
|
dialed number identification service dialed number identification service dnis service sold telecommunications companies corporate clients identifies originally dialed telephone number inbound call client may use information call routing internal destinations activation special call handling dnis service telephone company sends sequence typically four ten digits call setup direct inward dial service also provides dnis example company may different toll-free telephone number product line sells multilingual customer support call center handling calls multiple product lines corporate telephone system receives call analyzes dnis signaling may play appropriate recorded greeting interactive voice response ivr systems dnis used routing information dispatching purposes determine script service activated based number dialed reach ivr platform dnis commonly provided 800 900 services
|
Computer security
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.