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mvs multiple virtual storage commonly called mvs commonly used operating system system/370 system/390 ibm mainframe computers developed ibm unrelated ibm mainframe operating systems e.g. vse vm tpf first released 1974 mvs extended program products new names multiple times first ibm described mvs simply new release os/vs2 fact major rewrite os/vs2 release 1 upgrade os/360 mvt retained original code like mvt mainly written assembly language mvs core almost entirely written assembler xf although modules written pl/s performance-sensitive ones particular input/output supervisor ios ibm use os/vs2 emphasized upwards compatibility application programs ran mvt even need recompiling run mvs job control language files could used unchanged utilities non-core facilities like tso ran unchanged ibm users almost unanimously called new system mvs start ibm continued use term mvs naming later major versions mvs/xa os/360 mft multitasking fixed number tasks provided multitasking several memory partitions fixed size set operating system installed operator redefined example could small partition two medium partitions large partition two large programs ready run one would wait finished vacated large partition os/360 mvt multitasking variable number tasks enhancement refined memory use instead using fixed-size memory partitions mvt allocated memory regions job steps needed provided enough contiguous physical memory available significant advance mft memory management weaknesses job allocated memory dynamically sort programs database management systems programmers estimate job maximum memory requirement pre-define mvt job step contained mix small large programs wasted memory small programs ran seriously memory could become fragmented i.e. memory used current jobs could divided uselessly small chunks areas used current jobs remedy wait current jobs finished starting new ones early 1970s ibm sought mitigate difficulties introducing virtual memory ibm called virtual storage allowed programs request address spaces larger physical memory original implementations single virtual address space shared jobs os/vs1 os/360 mft within single virtual address space os/vs2 svs os/360 mvt within single virtual address space os/vs1 svs principle disadvantages mft mvt impacts less severe jobs could request much larger address spaces requests came 16 mb pool even physical storage smaller mid-1970s ibm introduced mvs supported virtual storage larger available real storage svs also allowed indefinite number applications run different address spaces two concurrent programs might try access virtual memory address virtual memory system redirected requests different areas physical memory address spaces consisted three areas operating system one instance shared jobs application area unique application shared virtual area used various purposes including inter-job communication ibm promised application areas would always least 8 mb made mvs perfect solution business problems resulted need run applications mvs maximized processing potential providing multiprogramming multiprocessing capabilities like mvt os/vs2 svs predecessors mvs supported multiprogramming program instructions associated data scheduled control program given processing cycles unlike single-programming operating system systems maximize use processing potential dividing processing cycles among instructions associated several different concurrently running programs way control program wait i/o operation complete proceeding executing instructions multiple programs computer able switch back forth active inactive programs early editions mvs mid-1970s among first ibm os series support multiprocessor configurations though m65mp variant os/360 running 360 models 65 67 provided limited multiprocessor support 360 model 67 also hosted multiprocessor capable tss/360 mts cp-67 operating systems multiprocessing systems execute instructions simultaneously offer greater processing power single-processing system result mvs able address business problems brought need process large amounts data multiprocessing systems either loosely coupled means computer access common workload tightly coupled means computers share real storage controlled single copy operating system mvs retained loosely coupled multiprocessing attached support processor asp tightly coupled multiprocessing os/360 model 65 multiprocessing tightly coupled systems two cpus shared concurrent access memory copy operating system peripherals providing greater processing power degree graceful degradation one cpu failed loosely coupled configurations group processors single tightly coupled memory operating system shared peripherals operating system component jes3 allowed managing whole group one console provided greater resilience let operators decide processor run jobs central job queue mvs jes3 gave users opportunity network together two data processing systems via shared disks channel-to-channel adapters ctca capability eventually became available jes2 users multi-access spool mas mvs originally supported 24-bit addressing i.e. 16 mb underlying hardware progressed supported 31-bit xa esa 2048 mb z/os 64-bit addressing significant motives rapid upgrade 31-bit addressing growth large transaction-processing networks mostly controlled cics ran single address space—and db2 relational database management system needed 8 mb application address space run efficiently early versions configured two address spaces communicated via shared virtual area imposed significant overhead since communications transmit via operating system main user interfaces mvs job control language jcl originally designed batch processing 1970s onwards also used start allocate resources long-running interactive jobs cics tso time sharing option interactive time-sharing interface mainly used run development tools end-user information systems ispf tso application users 3270-family terminals later vm well allows user accomplish tasks tso command line menu form oriented manner full screen editor file browser tso basic interface command line although facilities added later form-driven interfaces mvs took major step forward fault-tolerance built earlier stae facility ibm called software recovery ibm decided years practical real-world experience mvt business world system failures major impacts customer businesses ibm decided take major design jump assume despite best software development testing techniques 'problems occur profound assumption pivotal adding great percentages fault-tolerance code system likely contributed system success tolerating software hardware failures statistical information hard come prove value design features measure 'prevented 'recovered problems ibm many dimensions enhanced fault-tolerant software recovery rapid problem resolution features time design specified hierarchy error-handling programs system kernel/'privileged mode called functional recovery routines user 'task 'problem program mode called estae extended specified task abnormal exit routines invoked case system detected error actually hardware processor storage error software error recovery routine made 'mainline function reinvokable captured error diagnostic data sufficient debug causing problem either 'retried reinvoke mainline 'percolated escalated error processing next recovery routine hierarchy thus error system captured diagnostic data attempted perform repair keep system worst thing possible take user address space 'job case unrepaired errors though initial design point recent mvs version z/os recovery program guaranteed recovery routine recovery routine recovery routine recovery structure embedded basic mvs control program programming facilities available used application program developers 3rd party developers practically mvs software recovery made problem debugging easier difficult software recovery requires programs leave 'tracks thus facilitating debugging—but fact processing progresses despite error overwrite tracks early data capture time error maximizes debugging facilities exist recovery routines task system mode ibm included additional criteria major software problem required ibm service mainline component failed initiate software recovery considered valid reportable failure also recovery routine failed collect significant diagnostic data original problem solvable data collected recovery routine ibm standards dictated fault reportable required repair thus ibm standards rigorously applied encouraged continuous improvement ibm introduced on-demand hypervisor major serviceability tool called dynamic support system dss first release mvs facility could invoked initiate session create diagnostic procedures invoke already-stored procedures procedures 'trapped special events loading program device i/o system procedure calls triggered activation previously defined procedures procedures could invoked recursively allowed reading writing data alteration instruction flow program event recording hardware used due overhead tool removed customer-available mvs systems program-event recording per exploitation performed enhancement diagnostic slip command introduction per support slip/per su 64/65 1978 multiple copies mvs ibm operating systems could share machine machine controlled vm/370 case vm/370 real operating system regarded guest operating systems applications unusually high privileges result later hardware enhancements one instance operating system either mvs vm guests could also occupy logical partition lpar instead entire physical system multiple mvs instances organized collectively administered structure called systems complex sysplex introduced september 1990 instances interoperate software component called cross-system coupling facility xcf hardware component called hardware coupling facility cf integrated coupling facility icf co-located mainframe hardware multiple sysplexes joined via standard network protocols ibm proprietary systems network architecture sna recently via tcp/ip z/os operating system mvs recent descendant also native support execute posix single unix specification applications support began mvs/sp v4r3 ibm obtained unix 95 certification z/os v1r2 later system typically used business banking applications often written cobol cobol programs traditionally used transaction processing systems like ims cics program running cics special exec cics statements inserted cobol source code preprocessor translator replaces exec cics statements appropriate cobol code call cics program compiled — altogether unlike sql used call db2 applications also written languages c c++ java assembly language fortran basic rpg rexx language support packaged common component called language environment le allow uniform debugging tracing profiling language independent functions mvs systems traditionally accessed 3270 terminals pcs running 3270 emulators however many mainframe applications days custom web gui interfaces z/os operating system built-in support tcp/ip system management done past 3270 terminal done hardware management console hmc increasingly web interfaces operator consoles provided 2074 emulators unlikely see s/390 zseries processor real 3270 connected native character encoding scheme mvs peripherals ebcdic tr instruction made easy translate 7- 8-bit codes time ibm added hardware-accelerated services perform translation larger codes hardware-specific service unicode transforms software support e.g. ascii iso/iec 8859 utf-8 utf-16 utf-32 software translation services take source destination code pages inputs files properly called data sets mvs names files organized catalogs vsam files data set names dsns mainframe term filenames organized hierarchy whose levels separated dots e.g dept01.system01.file01 level hierarchy eight characters long total filename length maximum 44 characters including dots convention components separated dots used organize files similarly directories operating systems example utility programs performed similar functions windows explorer without gui usually batch processing mode adding renaming deleting new elements reporting contents specified element however unlike many systems levels usually actual directories naming convention like original macintosh file system folder hierarchy illusion maintained finder tso supports default prefix files similar current directory concept racf supports setting access controls based filename patterns analogous access controls directories platforms members os family mvs data sets record-oriented mvs inherited three main types predecessors sequential isam datasets could store either fixed-length variable length records types could occupy one disk volume based vtoc disk structure early ibm database management systems used various combinations isam bdam datasets usually bdam actual data storage isam indexes early 1970s ibm virtual memory operating systems introduced new file management component vsam provided similar facilities vsam formats became basis ibm database management systems ims/vs db2 usually esds actual data storage ksds indexes vsam also included catalog component used mvs master catalog partitioned data sets pds sequential data sets subdivided members could processed sequential files right like folder hierarchical file system important use pdses program libraries system administrators used main pds way allocate disk space project project team created edited members uses pdss libraries frequently used job control procedures procs “ copy books ” programming language statements record definitions used several programs generation data groups gdgs groups like named data sets referenced absolute generation number offset recent generation originally designed support grandfather-father-son backup procedures file modified changed version became new son previous son became father previous father became grandfather previous grandfather deleted one could set gdgs 3 generations applications used gdgs collect data several sources feed information one program collecting program created new generation file final program read whole group single sequential file specifying generation jcl modern versions mvs e.g. z/os also support posix-compatible slash filesystems along facilities integrating two filesystems os make mvs dataset appear file posix program subsystem newer filesystems include hierarchical file system hfs confused apple hierarchical file system zfs confused sun zfs programs running network-connected computers as/400 use local data management interfaces transparently create manage access vsam record-oriented files using client-server products implemented according distributed data management architecture ddm ddm also base architecture mvs db2 server implements distributed relational database architecture drda mvs part z/os older mvs releases longer supported ibm since 2007 64-bit z/os releases supported z/os supports running older 24-bit 31-bit mvs applications alongside 64-bit applications mvs releases 3.8j 24-bit released 1981 freely available possible run mvs 3.8j release mainframe emulators free mvs/370 generic term versions mvs operating system prior mvs/xa system/370 architecture time mvs released supported 24-bit virtual addresses mvs/370 operating system architecture based 24-bit address 24-bit address length programs running mvs/370 given 16 megabytes contiguous virtual storage mvs/xa multiple virtual storage/extended architecture version mvs supported 370-xa architecture expanded addresses 24 bits 31 bits providing 2 gigabyte addressable memory area also supported 24-bit legacy addressing mode older 24-bit applications i.e stored 24-bit address lower 24 bits 32-bit word utilized upper 8 bits word purposes mvs/esa mvs enterprise system architecture version mvs first introduced mvs/sp version 3 february 1988 replaced by/renamed os/390 late 1995 subsequently z/os mvs/esa openedition upgrade version 4 release 3 mvs/esa announced february 1993 support posix standards initial release national institute standards technology nist certification federal information processing standard fips 151 compliance subsequent releases certified higher levels organizations e.g x/open successor open group included 1 million new lines code provide api shell utilities extended user interface works hierarchical file system provided dfsms data facility system managed storage shell utilities based mortice kerns interopen products independent specialists estimate 80 open systems-compliant—more unix systems dce2 support announced february 1994 many application development tools march 1995 mid 1995 open features became standard part vanilla mvs/esa sp version 5 release 1 ibm stopped distinguishing openedition operating system os/390 became unix system services kept name z/os late 1995 ibm bundled mvs several program products changed name mvs/esa os/390 current level mvs marketed z/os japanese mainframe manufacturers fujitsu hitachi repeatedly illegally obtained ibm mvs source code internal documentation one 20th century famous cases industrial espionage fujitsu relied heavily ibm code msp mainframe operating system likewise hitachi vos3 operating system msp vos3 heavily marketed japan still hold substantial share mainframe installed base also degree countries notably australia even ibm bugs documentation misspellings faithfully copied ibm cooperated u.s. federal bureau investigation sting operation reluctantly supplying fujitsu hitachi proprietary mvs mainframe hardware technologies course multi-year investigations culminating early 1980s—investigations implicated senior company managers even japanese government officials amdahl however involved fujitsu theft ibm intellectual property communications amdahl fujitsu amdahl specifications scrupulously cleansed ibm ip references ibm ip subsequent investigations ibm reached multimillion-dollar settlements fujitsu hitachi collecting substantial fractions companies profits many years reliable reports indicate settlements exceeded us 500,000,000 three companies long since amicably agreed many joint business ventures example 2000 ibm hitachi collaborated developing ibm z900 mainframe model historical copying msp vos3 properly classified forks mvs many third party software vendors mvs-compatible products able produce msp- vos3-compatible versions little modification ibm introduced 64-bit z/architecture mainframes year 2000 ibm also introduced 64-bit z/os operating system direct successor os/390 mvs fujitsu hitachi opted license ibm z/architecture quasi-mvs operating systems hardware systems msp vos3 still nominally supported vendors maintain mvs 1980s architectural limitations present day since z/os still supports mvs-era applications technologies—indeed z/os still contains mvs code albeit greatly enhanced improved decades evolution—applications operational procedures running msp vos3 move z/os much easily operating systems
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Operating systems
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autoscaling autoscaling also spelled auto scaling auto-scaling sometimes also called automatic scaling method used cloud computing whereby amount computational resources server farm typically measured terms number active servers scales automatically based load farm closely related builds upon idea load balancing autoscaling offers following advantages autoscaling differs fixed daily weekly yearly cycle server use responsive actual usage patterns thus reduces potential downside many servers traffic load instance traffic usually lower midnight static scaling solution might schedule servers sleep night might result downtime night people happen use internet instance due viral news event autoscaling hand handle unexpected traffic spikes better list use terminology used amazon web services aws however alternative names noted terminology specific names amazon services used names amazon web services launched amazon elastic compute cloud ec2 service august 2006 allowed developers programmatically create terminate instances machines time initial launch aws offer autoscaling ability programmatically create terminate instances gave developers flexibility write code autoscaling third-party autoscaling software aws began appearing around april 2008 included tools scalr rightscale rightscale used animoto able handle facebook traffic adopting autoscaling may 18 2009 amazon launched autoscaling feature along elastic load balancing part amazon elastic compute cloud autoscaling integral component amazon ec2 offering autoscaling amazon web services done web browser command line tool.. may 2016 autoscaling also offered aws ecs service on-demand video provider netflix documented use autoscaling amazon web services meet highly variable consumer needs found aggressive scaling delayed cautious scaling served goals uptime responsiveness best article techcrunch zev laderman co-founder ceo newvem service helps optimize aws cloud infrastructure recommended startups use autoscaling order keep amazon web services costs low various best practice guides aws use suggest using autoscaling feature even cases load variable autoscaling offers two advantages automatic replacement instances become unhealthy reason hardware failure network failure application error automatic replacement spot instances get interrupted price capacity reasons making feasible use spot instances production purposes netflix internal best practices require every instance autoscaling group conformity monkey terminates instance autoscaling group order enforce best practice june 27 2013 microsoft announced adding autoscaling support windows azure cloud computing platform documentation feature available microsoft developer network oracle cloud platform allows server instances automatically scale cluster defining auto-scaling rule rules based cpu and/or memory utilization determine add remove nodes november 17 2014 google compute engine announced public beta autoscaling feature use google cloud platform applications march 2015 autoscaling tool still beta blog post august 2014 facebook engineer disclosed company started using autoscaling bring energy costs blog post reported 27 decline energy use low traffic hours around midnight 10-15 decline energy use typical 24-hour cycle kubernetes horizontal pod autoscaler automatically scales number pods replication controller deployment replicaset based observed cpu utilization beta support application-provided metrics autoscaling default uses reactive decision approach dealing traffic scaling scaling happens response real-time changes metrics cases particularly changes occur quickly reactive approach scaling insufficient two kinds autoscaling decision approaches described approach autoscaling changes made minimum size maximum size desired capacity autoscaling group specific times day scheduled scaling useful instance known traffic load increase decrease specific times day change sudden reactive approach based autoscaling respond fast enough aws autoscaling groups support scheduled scaling approach autoscaling uses predictive analytics idea combine recent usage trends historical usage data well kinds data predict usage future autoscale based predictions parts infrastructure specific workloads netflix found scryer predictive analytics engine gave better results amazon reactive autoscaling approach particular better november 20 2018 aws announced predictive scaling would available part autoscaling offering
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Distributed computing architecture
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peter lucas computer scientist peter lucas born 13 january 1935 vienna austria – 2 february 2015 california united states austrian computer scientist university professor peter lucas graduated 1953 studied telecommunications vienna university technology completed studies 1959 diploma thesis topic programming electronic calculating machines member heinz zemanek group responsible system programming mailüfterl first fully transistorized computer continental europe 1961 moved mailüfterl group technical university ibm company working ibm laboratory vienna worked formal description programming languages together hans bekić kurt walk heinz zemanek responsible formal definition ibm programming language pl/i using vienna definition language vdl important part formal method vdm addition worked together hans bekić compiler algol 60 time gave lectures lectures vienna university technology johannes kepler university linz covering theoretical foundations programming formal definition programming languages 1978 joined thomas j. watson research center yorktown heights new york united states worked experimental compiler projects 1979 moved ibm san josé california later ibm almaden research center 1988 worked john backus group definition implementation functional programming language fl october 1993 appointed full professor software technology graz university technology retiring emeritus position july 2001 1994 chairman formal methods europe fme corresponding member austrian academy sciences peter lucas died 2 february 2015 age 80
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Programming language topics
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impossible differential cryptanalysis cryptography impossible differential cryptanalysis form differential cryptanalysis block ciphers ordinary differential cryptanalysis tracks differences propagate cipher greater expected probability impossible differential cryptanalysis exploits differences impossible probability 0 intermediate state cipher algorithm lars knudsen appears first use form attack 1998 paper introduced aes candidate deal first presentation attract attention cryptographic community later year rump session crypto '98 eli biham alex biryukov adi shamir introduced name impossible differential used technique break 4.5 8.5 rounds idea 31 32 rounds nsa-designed cipher skipjack development led cryptographer bruce schneier speculate nsa previous knowledge impossible differential cryptanalysis technique since applied many ciphers khufu khafre e2 variants serpent mars twofish rijndael crypton zodiac hierocrypt-3 tea xtea mini-aes aria camellia shacal-2 biham biryukov shamir also presented relatively efficient specialized method finding impossible differentials called miss-in-the-middle attack consists finding two events probability one whose conditions met together
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Computer security
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hybrid kernel hybrid kernel operating system kernel architecture attempts combine aspects benefits microkernel monolithic kernel architectures used computer operating systems traditional kernel categories monolithic kernels microkernels nanokernels exokernels seen extreme versions microkernels hybrid category controversial due similarity hybrid kernels ordinary monolithic kernels term dismissed linus torvalds simple marketing idea behind hybrid kernel kernel structure similar microkernel implement structure manner monolithic kernel contrast microkernel nearly operating system services hybrid kernel still kernel space none reliability benefits services user space microkernel however ordinary monolithic kernel none performance overhead message passing context switching kernel user mode normally comes microkernel one prominent example hybrid kernel microsoft windows nt kernel powers operating systems windows nt family including windows 10 windows server 2019 powers windows phone 8 windows phone 8.1 xbox one nt-based windows classified hybrid kernel macrokernel rather monolithic kernel emulation subsystems run user-mode server processes rather kernel mode monolithic kernel large number design goals resemble design goals mach particular separation os personalities general kernel design conversely reason nt microkernel system system components run address space kernel would case monolithic design traditional monolithic design would microkernel per se kernel would implement broadly similar functionality nt microkernel kernel-mode subsystems windows nt design includes many objectives mach archetypal microkernel system one important structure collection modules communicate via well-known interfaces small microkernel limited core functions first-level interrupt handling thread scheduling synchronization primitives allows possibility using either direct procedure calls interprocess communication ipc communicate modules hence potential location modules different address spaces example either kernel space server processes design goals shared mach included support diverse architectures kernel abstractions general enough allow multiple operating system personalities implemented top object-oriented organisation primary operating system personality windows windows api always present emulation subsystem implements windows personality called client/server runtime subsystem csrss.exe versions nt prior 4.0 subsystem process also contained window manager graphics device interface graphics device drivers performance reasons however version 4.0 later modules often implemented user mode even monolithic systems especially designed without internal graphics support run kernel-mode subsystem applications run nt written one os personalities usually windows api native nt api documentation publicly available exception routines used device driver development os personality implemented via set user-mode dlls see dynamic-link library mapped application processes address spaces required together emulation subsystem server process described previously applications access system services calling os personality dlls mapped address spaces turn call nt run-time library ntdll.dll also mapped process address space nt run-time library services requests trapping kernel mode either call kernel-mode executive routines make local procedure calls lpcs appropriate user-mode subsystem server processes turn use nt api communicate application processes kernel-mode subsystems xnu kernel apple inc. acquired developed use macos ios watchos tvos operating systems released free open source software part darwin operating system xnu acronym x unix originally developed next nextstep operating system xnu hybrid kernel combining version 2.5 mach kernel developed carnegie mellon university components 4.3bsd object-oriented api writing drivers called driver kit apple acquired next mach component upgraded osfmk 7.3 microkernel apple uses heavily modified osfmk 7.3 functioning hybrid kernel parts freebsd included osfmk 7.3 includes applicable code university utah mach 4 kernel applicable code many mach 3.0 variants sprouted original carnegie mellon university mach 3.0 kernel bsd components upgraded code freebsd project driver kit replaced c++ api writing drivers called i/o kit like modern kernels xnu hybrid containing features monolithic microkernels attempting make best use technologies message passing capability microkernels enabling greater modularity larger portions os benefit protected memory well retaining speed monolithic kernels certain critical tasks xnu runs arm part ios ia-32 x86-64 based processors
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Computer architecture
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amd socket g3 socket g3 originally part codenamed piranha server platform supposed intermediate successor socket f socket f+ used amd opteron processor dual-processor 2p server platforms scheduled launched 2009 socket g3 would accompanied socket g3 memory extender socket g3mx connecting large amounts memory single microprocessor g3mx chip placed motherboard amd planned socket g3 arrive advent previously planned 8-core mcm chip code named montreal since q1 2008 plan 8-core mcm server chip based 45 nm k10.5 design scrapped favor 6-core fully integrated mpu design code named istanbul use existing socket f/f+ platform produced nvidia broadcom well fiorano introduced amd 2009 however socket g3 officially discontinued march 2008 socket successor socket f lga 1974-pin socket g34
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Computer architecture
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q-cert qatar computer emergency response team created december 2006 cert/cc ictqatar qatar coordination center dealing internet security problems q-cert first-ever cert established middle east plans q-cert first announced december 2006 ictqatar cert coordination center entered partnership signed cooperation agreement sans institute provide training courses cyber security specialists qatar government november 2016 first gcc cyber drill held auspices q-cert engaged internet security specialists four gcc countries goals q-cert
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Computer security
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oneindia oneindia.com indian online portal founded bg mahesh owned greynium information technologies pvt ltd website provides news updates sports events travel entertainment business lifestyle videos classifieds seven different indian languages english kannada hindi tamil telugu bengali gujarati malayalam
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Web technology
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corbascript corbascript object-oriented scripting language designed use corba
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Programming language topics
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damien sandras damien sandras known free software community due work gnome specifically ekiga leading open source softphone linux desktop one founders fosdem event dedicated free software developers europe fosdem initially created raphaël bauduin name osdem sandras joined bauduin helped setting event sandras one driving forces behind organization 7 years ekiga supported free software foundation specifically richard stallman alternative proprietary skype stallman e-mail signature contained mention softphone years sandras graduate university louvain uclouvain mentioned university portal university success stories leading ip startup dealing enterprise open source voip software
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Operating systems
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nokia 5230 nokia 5230 also known nokia 5230 nuron smartphone manufactured nokia running symbian os v9.4 s60 5th edition released november 2009 announced august year features 3.2 inch resistive touchscreen 3g internet support support microsd memory cards also supports a-gps bluetooth fm radio full html internet browsing however lacks support wi-fi due status entry-level smartphone released nokia 5530 nokia 5800 xpressmusic featured wi-fi support 3g 3g wi-fi respectively lifespan 5230 sold around 150 million units making one best selling phones date particular success developing countries nuron version released north america wcdma band iv aws enabled comes preloaded maps united states canada mexico january 2010 nokia announced ovi maps available free certain smartphones includes nokia 5230 thus enabling free offline voice guided navigation 180 countries 51.0.002 latest firmware version available
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Operating systems
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business intelligence development studio business intelligence development studio bids former ide microsoft used develop data analysis business intelligence solutions utilizing microsoft sql server analysis services reporting services integration services based microsoft visual studio development environment customized sql server services-specific extensions project types including tools controls projects reports etl dataflows olap cubes data mining structure bids functionality augmented bids helper visual studio add-in features extended enhance business intelligence development functionality sql server 2005 2008 2008 r2 bi development studio bids sql server 2012 sql server data tools ssdt bids helper hosted microsoft open source project hosting website codeplex business intelligence markup language biml used bids create end-to-end bi solutions translating biml metadata sql server integration services ssis sql server analysis services ssas assets microsoft sql server platform bids supported visual studio 2010 later replaced sql server data tools business intelligence
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Databases
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powerquicc powerquicc name several powerpc- power isa-based microcontrollers freescale semiconductor built around one powerpc cores communications processor module quicc engine separate risc core specialized tasks i/o communications atm security acceleration networking usb many components system-on-a-chip designs tailor made embedded applications powerquicc processors used networking automotive industrial storage printing consumer applications freescale using powerquicc processors part mobilegt platform freescale also manufactures quicc microcontrollers based older 68k technology four distinct lines processors mainly based processing power. mpc8xx family motorola first powerpc based embedded processors suited network processors system-on-a-chip devices core original implementation powerpc specification single issue four stage pipelined core mmu branch prediction unit speeds 133 mhz mpc821 introduced 1995 together mpc860 complete quicc engine slimmed version mpc850 reduced caches io ports came 1997 quicc communication processor module cpm offloads networking tasks cpu thus branding family powerquicc processors family differ on-chip features like usb serial pcmcia atm ethernet controllers different amount l1 caches ranging 1 kib 16 kib mpc8xx – powerquicc processors share common naming scheme powerquicc ii introduced 1998 direct descendant powerpc 603e core also goes name 603e g2 processors still 16/16 kib instruction/data l1 caches reaching frequencies 450 mhz communications processors used applications like voip systems telecom switches cellular base stations dslams powerquicc ii family processors phased favour powerful powerquicc ii pro line plans development core mpc82xx – powerquicc ii processors share common naming scheme introduced 2004 based e300 core enhanced powerpc 603e core 32/32 kib instruction/data l1 caches powerquicc ii pro used networking processors routers switches printers network-attached storage wireless access points dslams powerquicc ii pro processors reaches 677 mhz include multitude embedded technologies like usb pci ethernet security devices also use newer quicc engine network offload engine instead cpm used original powerquicc powerquicc ii series memory controller provides support ddr ddr2 sdrams mpc83xx – powerquicc ii pro processors share common naming scheme trailing e signifies processors built encryption module devices 834x name lacks quicc engine devices number like 836x one powerquicc iii processors based 32-bit power isa v.2.03 core called e500 introduced 2003 dual issue seven-stage pipeline double precision fpus 32/32 kib data instruction l1 caches multiple gigabit ethernet pci pcie rapidio ddr/ddr2 memory controllers security accelerators speeds ranges 533 mhz 1.5 ghz processors target enterprise level networking telecom applications high end storage printing imaging processors use older cpm module handling network processing offload use newer quicc engine powerquicc ii pro cpm quicc engine freescale marketing department nevertheless brand devices 85xx series powerquicc iii mpc85xx – powerquicc iii processors share common naming scheme trailing e signifies processors built-in encryption module powerquicc cease development favor software-compatible qoriq platform featuring powerpc e500 based processors single core multi-core 32 cores freescale keep manufacturing powerquicc processors foreseeable future existing customers help facilitate transition qoriq
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Computer architecture
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cronlab cronlab limited privately held limited company provides information security web filtering software solutions businesses consumers either directly via integration third party products cronlab offices london united kingdom gothenburg sweden cronlab founded gothenburg sweden introduced first anti-spam hardware appliances 2009 appliances received positive reviews industry media pc pro crn magazine sc magazine cited systems ease use quick set tested email filtering technology 99 accurate 2010 company moved headquarters london united kingdom also released software service hosted models spam filtering technology awarded recommendation techworld hosted email archiving solutions cide group toy manufacturer partnered cronlab development children tablet computer tablet called kurio features cronlab hosted web-filtering parental controls technology cronlab agreements distribution france belgium switzerland germany norway bulgaria moldova romania ireland united kingdom company security products aim protect email web threats spam spyware trojans viruses also provide email archiving solution cronlab products support multi-tenancy marketed isps msps consultants products also white labelled
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Computer security
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inter-language unification inter-language unification ilu method computer systems exchange data bridging differences way systems represent various kinds data even two systems run computer identical computer hardware many differences arise use different computer languages build systems object interfaces provided ilu hide implementation distinctions different languages different address spaces operating system types ilu used build multi-lingual object-oriented libraries class libraries well-specified language-independent interfaces also used implement distributed systems also used define document interfaces modules non-distributed programs ilu interfaces specified either object management group corba interface definition language omg idl ilu interface specification language isl ilu developed open source project xerox palo alto research center xerox parc 1991 2000 last release 2.0beta1 1997 2000 ilu used foundation experimental work next generation http protocol world wide web consortium http-ng activity result work particularly efficient experimental rpc protocol called w3ng developed along way efficiently multiplexing single tcp connection multiple channels directions called w3mux results http-ng experiment presented 2000 world wide web conference last release supported programming languages c++ corba2 mapping ansi c python java common lisp contributed support also available modula-3 guile scheme perl 5 ilu installed flavors unix sunos solaris hp-ux aix osf irix freebsd linux lynxos sco unix etc ms-windows 3.1 95 nt supported threaded posix solaris nt franz acl ppcr modula-3 event-loop xt tk xview operation one implementation goals maximize compatibility existing open standards result ilu provided support use omg corba idl interface description language thought corba orb system though omissions extensions corba spec ilu also included self-contained implementation onc rpc possible describe use existing rpc services ilu objects ilu also included self-contained implementation world wide web hypertext transfer protocol http could thus used implement object-oriented web browsers servers communication security provided gss-based context negotiation on-the-wire encryption
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Distributed computing architecture
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omron styled omron electronics company based kyoto japan omron established 1933 tateishi electric manufacturing company incorporated 1948 company originated area kyoto called name omron derived prior 1990 corporation known omron tateishi electronics 1980s early 1990s company motto machine work machines man thrill creation omron primary business manufacture sale automation components equipment systems generally known medical equipment digital thermometers blood pressure monitors nebulizers omron developed world first electronic ticket gate named ieee milestone 2007 one first manufacturers automated teller machines atm magnetic stripe card readers omron oilfield marine provider ac dc drive systems custom control systems oil gas related industries omron named one thomson reuters top 100 global innovators 2013 september 30 2015
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Computer security
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stephen wolfram stephen wolfram born 29 august 1959 british-american computer scientist physicist businessman known work computer science mathematics theoretical physics 2012 named inaugural fellow american mathematical society businessman founder ceo software company wolfram research worked chief designer mathematica wolfram alpha answer engine recent work knowledge-based programming expanding refining programming language mathematica called wolfram language stephen wolfram born london 1959 hugo sybil wolfram german jewish refugees united kingdom wolfram father hugo wolfram 1925–2015 textile manufacturer born bochum germany served managing director lurex company makers fabric lurex also author three novels emigrated england 1933 world war ii broke left school 15 subsequently found hard get job since regarded enemy alien adult took correspondence courses philosophy psychology wolfram mother sybil wolfram 1931–1993 born sybille misch originally berlin germany fellow tutor philosophy lady margaret hall university oxford 1964 1993 published two books philosophical logic introduction 1989 in-laws outlaws kinship marriage england 1987 translator claude lévi-strauss la pensée sauvage savage mind later disavowed translation daughter criminologist psychoanalyst kate friedlander 1902–1949 expert subject juvenile delinquency physician walter misch 1889–1943 together wrote die vegetative genese der neurotischen angst und ihre medikamentöse beseitigung reichstag fire 1933 emigrated berlin germany england parents jewish psychoanalyst paula heimann 1899–1982 stephen wolfram married mathematician four children together stephen son christopher began degree course mathematics computer science 2018 co-inventor patented method computing device optically recognizing mathematical expressions christopher presented led workshops several highly-regarded conferences events including south southwest interactive university oxford summer school mit independent activities period 2016 awarded best technical advisor raw science film festival work movie arrival among many personal achievements serves programmer wolfram research wolfram educated eton college left prematurely 1976 entered st. john college oxford age 17 found lectures awful left 1978 without graduating attend california institute technology following year received phd particle physics 19 november 1979 age 20 wolfram thesis committee composed richard feynman peter goldreich frank j. sciulli steven frautschi chaired richard d. field young child wolfram difficulties learning arithmetic age 12 wrote directory physics age 14 written three books particle physics wolfram age 15 began research applied quantum field theory particle physics published scientific papers topics included matter creation annihilation fundamental interactions elementary particles currents hadronic leptonic physics parton model published professional peer-reviewed scientific journals including nuclear physics b australian journal physics nuovo cimento physical review working independently wolfram published widely cited paper heavy quark production age 18 nine papers continued research publish particle physics early twenties wolfram work geoffrey c. fox theory strong interaction still used experimental particle physics 1981 letter feynman gerald freund giving reference wolfram macarthur grant appears feynman collected letters perfectly reasonable deviations beaten track following phd wolfram joined faculty caltech became youngest recipient macarthur fellowships 1981 age 21 1983 wolfram left school natural sciences institute advanced study princeton conducted research cellular automata mainly computer simulations produced series papers systematically investigating class elementary cellular automata conceiving wolfram code naming system one-dimensional cellular automata classification scheme complexity behaviour conjectured rule 110 cellular automaton might turing complete later proved correct 1985 letter feynman wolfram also appears feynman letters response wolfram writing thinking creating kind institute might study complex systems feynman tells wolfram understand ordinary people advises find way research little contact non-technical people possible mid-1980s wolfram worked simulations physical processes turbulent fluid flow cellular automata connection machine alongside feynman helped initiate field complex systems 1984 participant founding workshops santa fe institute along nobel laureates murray gell-mann manfred eigen philip warren anderson future laureate frank wilczek 1986 founded center complex systems research ccsr university illinois urbana–champaign 1987 journal complex systems first journal field complex systems published many papers course three decades complex systems developed broad base readers contributors academia industry government general public 50 countries around world wolfram led development computer algebra system smp symbolic manipulation program caltech physics department 1979–1981 dispute administration intellectual property rights regarding smp—patents copyright faculty involvement commercial ventures—eventually caused resign caltech smp developed marketed commercially inference corp. los angeles 1983–1988 1983 wolfram joined institute advanced study princeton new jersey-based former home albert einstein time longer interested particle physics instead began pursuing viewed creative areas — specifically cellular automata wolfram methodically analyzed sets rules developing classification system rated complexity various cellular automata — intention clarifying way view complexity real world wolfram mind studying results cellular-automata runs computer could unlock deep truths universe wolfram cellular-automata work came cited 10,000 papers 1986 wolfram left institute advanced study university illinois urbana–champaign founded center complex systems research started develop computer algebra system mathematica first released 23 june 1988 left academia 1987 founded wolfram research continues develop market program near end sybil wolfram life part research in-laws outlaws used son program mathematica analyze data wolfram younger brother conrad wolfram serves ceo wolfram research europe ltd. 1992 2002 worked controversial book new kind science presents empirical study simple computational systems additionally argues fundamental reasons types systems rather traditional mathematics needed model understand complexity nature wolfram conclusion universe digital nature runs fundamental laws described simple programs predicts realization within scientific communities major revolutionary influence physics chemistry biology majority scientific areas general reason book title since release book 2002 wolfram split time developing mathematica encouraging people get involved subject matter new kind science giving talks holding conferences starting summer school devoted topic beginning may 2017 15th anniversary hardcover publication free electronic version new kind science launched includes complete access high-resolution images wolfram axiom result computer exploration new kind science looking shortest single axiom equivalent axioms boolean algebra propositional calculus result search axiom six nand operations three variables equivalent boolean algebra vertical bar represents nand logical operation also known sheffer stroke 25 candidates precisely set sheffer identities length less equal 15 elements excluding mirror images noncommutative models size less equal 4 variables 2003 wolfram hosted first wolfram summer school brown university — program designed provide educational career opportunities learning conducting projects frontiers science technology innovation 2007 summer school began hosted university vermont burlington exception year 2009 held istituto di scienza e tecnologie dell'informazione cnr pisa italy 2012 program held curry college milton massachusetts since 2013 wolfram summer school held annually bentley university waltham massachusetts new kind science idea exploring new abstract universe computational universe simple programs new kind science wolfram shows simple programs computational universe capture essence complexity – beauty – many systems nature led creation wolfram tones works taking simple programs wolfram computational universe applying music theory wolfram language algorithms render music program effect defines virtual world special story — wolfram tones captures musical composition new kind science wolfram found simplest known universal turing machine — 2 states 5 colors however also extensive search simpler turing machines found much simpler candidate universality 2,3 turing machine 14 may 2007 fifth anniversary publication new kind science wolfram announced 25,000 prize first person determine whether 2,3 turing machine actually universal could provide proof five months contest announcement undergraduate student birmingham uk successfully found 2,3 turing machine universal provided 40-page paper prove findings march 2009 wolfram announced wolfram|alpha answer engine wolfram|alpha later launched may 2009 paid-for version extra features launched february 2012 engine based natural language processing large library algorithms answers queries using approach described new kind science application programming interface allows applications extend enhance alpha wolfram believes wolfram alpha comes common use raise level scientific things average person wolfram alpha one answer engines behind microsoft bing apple siri answering factual questions 2010 wolfram co-founded touchpress along theodore gray max whitby john cromie company specialised creating in-depth premium apps games covering wide range educational subjects designed children parents students educators since launch touchpress published 100 apps march 2014 annual south southwest sxsw event wolfram officially announced wolfram language new general multi-paradigm programming language currently better known multi-paradigm computational communication language documentation language pre-released october 2013 coincide bundling mathematica wolfram language every raspberry pi computer wolfram language existed 25 years primary programming language used mathematica officially named 2014 wolfram son christopher wolfram appeared program sxsw giving live-coding demonstration using wolfram language blogged wolfram language wolfram research 8 december 2015 wolfram published book elementary introduction wolfram language introduce people knowledge programming wolfram language kind computation allows release second edition book coincided ceo hire competition 2017 collision tech conference beginning 2017 wolfram began live stream internal wolfram language development meetings meetings viewers encouraged submit questions comments related development programming language viewers known suggest new functions would like see developed name new functions help solve complex issues faced stephen wolfram research development team live streamed meetings viewed twitch.tv youtube live facebook live archived live streams also accessed personal website significance data products wolfram creates transfers life extensive log personal analytics including emails received sent keystrokes made meetings events attended phone calls even physical movement dating back 1980s preface new kind science noted recorded one-hundred million keystrokes one-hundred mouse miles stated personal analytics give us whole new dimension experiencing lives stephen wolfram christopher wolfram involved helping create alien language film arrival used wolfram language since 2018 wolfram producing podcast podcast stephen discusses topics ranging history science future civilization ethics ai
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Programming language topics
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reiser4 reiser4 computer file system successor reiserfs file system developed scratch namesys sponsored darpa well linspire reiser4 named former lead developer hans reiser reiser4 patch set still maintained according phoronix unlikely merged mainline linux without corporate backing goals reiser4 file system advanced reiser4 features user-defined transactions also available lack vfs api present reiser4 lacks standard file system features online repacker similar defragmentation utilities provided file systems creators reiser4 say implement later sooner someone pays reiser4 uses b*-trees conjunction dancing tree balancing approach underpopulated nodes merged flush disk except memory pressure transaction completes system also allows reiser4 create files directories without waste time space fixed blocks synthetic benchmarks performed namesys 2003 show reiser4 10 15 times faster serious competitor ext3 working files smaller 1 kib namesys benchmarks suggest typically twice performance ext3 general-purpose filesystem usage patterns benchmarks 2006 show results reiser4 slower many operations benchmarks conducted 2013 linux kernel version 3.10 show reiser4 considerably faster various tests compared in-kernel filesystems ext4 btrfs xfs reiser4 patches linux 2.6 3.x 4.x 5.x. reiser4 merged mainline linux kernel consequently still supported many linux distributions however predecessor reiserfs v3 widely adopted reiser4 also available andrew morton -mm kernel sources zen patch set linux kernel developers claim reiser4 follow linux coding standards hans reiser suggested political reasons latest released reiser4 kernel patches tools downloaded reiser4 project page sourceforge.net hans reiser convicted murder april 28 2008 leaving future reiser4 uncertain arrest employees namesys assured would continue work events would slow software development immediate future order afford increasing legal fees hans reiser announced december 21 2006 going sell namesys march 26 2008 sold although website unavailable january 2008 edward shishkin employee programmer namesys quoted cnet interview saying commercial activity namesys stopped shishkin others continued development reiser4 making source code available shishkin web site later relocated kernel.org since 2008 namesys employees received 100 sponsored funding darpa 2010 phoronix wrote edward shishkin exploring options get reiser4 merged linux kernel mainline file system still updated new kernel releases submitted merging 2015 michael larabel metioned unlikely happen without corporate backing suggested april 2019 main obstacle could renaming reiser4 refers initial author involved murder case
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Computer file systems
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data structure alignment data structure alignment refers way data arranged accessed computer memory consists three separate related issues data alignment data structure padding packing cpu modern computer hardware performs reads writes memory efficiently data naturally aligned generally means data address multiple data size data alignment refers aligning elements according natural alignment ensure natural alignment may necessary insert padding structure elements last element structure although data structure alignment fundamental issue modern computers many computer languages computer language implementations handle data alignment automatically ada pl/i pascal certain c c++ implementations rust c assembly language allow least partial control data structure padding may useful certain special circumstances memory address said n-byte aligned multiple n bytes n power 2 context byte smallest unit memory access i.e memory address specifies different byte n -byte aligned address would minimum log n least-significant zeros expressed binary alternate wording b-bit aligned designates b/8 byte aligned address ex 64-bit aligned 8 bytes aligned memory access said aligned data accessed n bytes long datum address n -byte aligned memory access aligned said misaligned note definition byte memory accesses always aligned memory pointer refers primitive data n bytes long said aligned allowed contain addresses n -byte aligned otherwise said unaligned memory pointer refers data aggregate data structure array aligned primitive datum aggregate aligned note definitions assume primitive datum power two bytes long case 80-bit floating-point x86 context influences conditions datum considered aligned data structures stored memory stack static size known bounded heap dynamic size known unbounded computer accesses memory single memory word time long memory word size least large largest primitive data type supported computer aligned accesses always access single memory word may true misaligned data accesses highest lowest bytes datum within memory word computer must split datum access multiple memory accesses requires lot complex circuitry generate memory accesses coordinate handle case memory words different memory pages processor must either verify pages present executing instruction able handle tlb miss page fault memory access instruction execution processor designs deliberately avoid introducing complexity instead yield alternative behavior event misaligned memory access example implementations arm architecture prior armv6 isa require mandatory aligned memory access multi-byte load store instructions depending specific instruction issued result attempted misaligned access might round least significant bits offending address turning aligned access sometimes additional caveats throw mmu exception mmu hardware present silently yield potentially unpredictable results starting armv6 architecture support added handle unaligned access many necessarily circumstances single memory word accessed operation atomic i.e whole memory word read written devices must wait read write operation completes access may true unaligned accesses multiple memory words e.g first word might read one device words written another device second word read first device value read neither original value updated value although failures rare difficult identify although compiler interpreter normally allocates individual data items aligned boundaries data structures often members different alignment requirements maintain proper alignment translator normally inserts additional unnamed data members member properly aligned addition data structure whole may padded final unnamed member allows member array structures properly aligned padding inserted structure member followed member larger alignment requirement end structure changing ordering members structure possible change amount padding required maintain alignment example members sorted descending alignment requirements minimal amount padding required minimal amount padding required always less largest alignment structure computing maximum amount padding required complicated always less sum alignment requirements members minus twice sum alignment requirements least aligned half structure members although c c++ allow compiler reorder structure members save space languages might also possible tell c c++ compilers pack members structure certain level alignment e.g pack 2 means align data members larger byte two-byte boundary padding members one byte long one use packed structures conserve memory example structure containing single byte four-byte integer would require three additional bytes padding large array structures would use 37.5 less memory packed although accessing structure might take longer compromise may considered form space–time tradeoff although use packed structures frequently used conserve memory space may also used format data structure transmission using standard protocol however usage care must also taken ensure values struct members stored endianness required protocol often network byte order may different endianness used natively host machine following formulas provide number padding bytes required align start data structure mod modulo operator example padding add offset 0x59d 4-byte aligned structure 3 structure start 0x5a0 multiple 4 however alignment offset already equal align second modulo align offset mod align mod align return zero therefore original value left unchanged since alignment definition power two modulo operation reduced bitwise boolean operation following formulas produce aligned offset bitwise bitwise data structure members stored sequentially memory structure member data1 always precede data2 data2 always precede data3 type short stored two bytes memory member data structure depicted would 2-byte aligned data1 would offset 0 data2 offset 2 data3 offset 4 size structure would 6 bytes type member structure usually default alignment meaning unless otherwise requested programmer aligned pre-determined boundary following typical alignments valid compilers microsoft visual c++ borland/codegear c++builder digital mars dmc gnu gcc compiling 32-bit x86 notable differences alignment lp64 64-bit system compared 32-bit system data types dependent implementation structure members various types totaling 8 bytes compilation compilation data structure supplemented padding bytes ensure proper alignment members compiled size structure 12 bytes important note last member padded number bytes required total size structure multiple largest alignment structure member alignment int case 4 linux-32bit/gcc case 3 bytes added last member pad structure size 12 bytes alignment int × 3 example total size structure 5 size multiple 4 alignment float example total size structure 5 8 either size multiple 2 alignment short 2 linux-32bit/gcc possible change alignment structures reduce memory require conform existing format reordering structure members changing compiler ’ alignment “ packing ” structure members compiled size structure matches pre-compiled size 8 bytes note replaced thus eliminated longer necessary structure already aligned size long word alternative method enforcing structure aligned one byte boundary cause pre-processor discard pre-determined alignment structure members thus padding bytes would inserted standard way defining alignment structure members compilers use directives specify packing inside source files example structure would compiled size 6 bytes 32-bit system directives available compilers microsoft borland gnu many others another example microsoft compilers particularly risc processor unexpected relationship project default packing /zp directive directive directive used reduce packing size structure project default packing leads interoperability problems library headers use example project packing smaller reason setting project packing value default 8 bytes would break directives used library headers result binary incompatibilities structures limitation present compiling x86 would beneficial allocate memory aligned cache lines array partitioned one thread operate sub-array boundaries unaligned cache lines could lead performance degradation example allocate memory double array size 10 aligned cache 64 bytes alignment concerns affect areas much larger c structure purpose efficient mapping area hardware address translation mechanism pci remapping operation mmu instance 32-bit operating system 4 kib 4096 bytes page arbitrary 4 kib chunk data instead usually region memory aligned 4 kib boundary aligning page page-sized boundary lets hardware map virtual address physical address substituting higher bits address rather complex arithmetic example assume tlb mapping virtual address 0x2cfc7000 physical address 0x12345000 note addresses aligned 4 kib boundaries accessing data located virtual address va=0x2cfc7abc causes tlb resolution 0x2cfc7 0x12345 issue physical access pa=0x12345abc 20/12-bit split luckily matches hexadecimal representation split 5/3 digits hardware implement translation simply combining first 20 bits physical address 0x12345 last 12 bits virtual address 0xabc also referred virtually indexed abc physically tagged 12345 block data size 2 1 always one sub-block size 2 aligned 2 bytes dynamic allocator knowledge alignment used provide aligned buffers price factor two space loss aligntonext p r works adding aligned increment clearing r least significant bits p possible implementation
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Programming language topics
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ultra 30 ultra 30 family sun microsystems workstations based ultrasparc ii microprocessor code-named quark member sun ultra series launched may 1997 shipped solaris 2.6 ultra 30 reached end-of-life may 1999 ultra 30 ran single ultrasparc ii cpu however compatible two models 250 mhz module 501-4857 300 mhz module 501-4849 system supports two ultra scsi hard drives 16 dimm slots maximum 2gb memory capacity machine also featured four full-sized pci slots two upa slots two rs-232c/rs-423 serial ports 100base-t fastethernet
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Computer architecture
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crypto book crypto code rebels beat government saving privacy digital age book cryptography written steven levy published 2001 levy details emergence public key cryptography digital signatures struggle national security agency nsa cypherpunks book details creation data encryption standard des rsa clipper chip
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Computer security
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skipper computer software skipper visualization tool code/schema generator php orm frameworks like doctrine2 doctrine propel cakephp used create database abstraction layer skipper developed czech company inventic s.r.o based brno known orm designer prior rebranding 2014 skipper built qt framework import/export schema definitions uses xsl transformations powered libxslt library imported source files first converted xml format conversion xml simple conversion yml creating abstract syntax tree subsequent conversion xml php annotations import/export scripts configured javascript freely customized frameworks supported visual model schema files generation skipper created internal tool web applications developed inventic first published commercial tool name orm designer 2009 application reworked optimized january 2013 released orm designer 2 may 2013 orm designer became part south moravian innovation center incubator program support program innovative technological startups june 2014 orm designer version 3 released rebranded name skipper
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Databases
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non-repudiation non-repudiation refers situation statement author successfully dispute authorship validity associated contract term often seen legal setting authenticity signature challenged instance authenticity repudiated example mallory buys cell phone 100 writes paper cheque check payment signs cheque pen later finds ca n't afford claims cheque forgery unfortunately signature guarantees mallory could signed cheque mallory bank must pay cheque non-repudiation mallory repudiate cheque practice pen-and-paper signatures n't hard forge digital signatures hard break general non-repudiation involves associating actions changes unique individual example secure area may use key card access system non-repudiation would violated key cards shared lost stolen cards immediately reported similarly owner computer account must allow others use giving away password policy implemented enforce prevents owner account denying actions performed account digital security non-repudiation means proof data integrity typically easiest requirements accomplish data hash sha2 usually ensures data changed undetectably even safeguard possible tamper data transit either man-in-the-middle attack phishing data integrity best asserted recipient already possesses necessary verification information common methods provide non-repudiation context digital communications storage message authentication codes mac useful communicating parties arranged use shared secret possess digital signatures powerful tool provides non-repudiation publicly verifiable manner note goal achieve confidentiality cases mac digital signature one simply appends tag otherwise plaintext visible message confidentiality also required encryption scheme combined digital signature form authenticated encryption could used verifying digital origin means certified/signed data likely came someone possesses private key corresponding signing certificate key used digitally sign message properly safeguarded original owner digital forgery occur mitigate risk people repudiating signatures standard approach involve trusted third party two common ttps forensic analysts notaries forensic analyst specializing handwriting compare signature known valid signature assess legitimacy notary witness verifies individual identity checking credentials affixing certification person signing claim notary provides extra benefit maintaining independent logs transactions complete types credentials checked another signature verified forensic analyst double security makes notaries preferred form verification digital information commonly employed ttp certificate authority issues public key certificates public key certificate used anyone verify digital signatures without shared secret signer verifier role certificate authority authoritatively state certificate belongs meaning person entity possesses corresponding private key however digital signature forensically identical legitimate forged uses someone possesses private key create valid digital signature protecting private key idea behind united states department defense common access card cac never lets key leave card means use card encryption digital signatures person needs personal identification number pin code necessary unlock
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Computer security
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mumps mumps massachusetts general hospital utility multi-programming system general-purpose computer programming language originally designed 1966 healthcare industry differentiating feature built-in database enabling high-level access disk storage using simple symbolic program variables subscripted arrays similar variables used languages access main memory continues used today many large hospitals banks provide high-throughput transaction data processing mumps developed neil pappalardo robert greenes curt marble dr. octo barnett animal lab massachusetts general hospital mgh boston 1966 1967 original mumps system like unix years later built spare dec pdp-7 octo barnett neil pappalardo also involved mgh planning hospital information system obtained backward compatible pdp-9 began using mumps admissions cycle laboratory test reporting mumps interpreted language yet even incorporated hierarchical database file system standardize interaction data aspects mumps traced rand corporation joss bbn telcomp stringcomp mumps team deliberately chose include portability machines design goal another feature widely supported machines era operating systems computer hardware multitasking also built language portability soon useful mumps shortly adapted dec pdp-15 lived time mumps developed support government research grant mumps released public domain longer requirement grants soon ported number systems including popular dec pdp-8 data general nova dec pdp-11 artronix pc12 minicomputer word mumps spread mostly medical community early 1970s widespread use often locally modified needs early 1970s many varied implementations mumps range hardware platforms widespread dec mumps-11 pdp-11 meditech miis 1972 many mumps users attended conference standardized then-fractured language created mumps users group mumps development committee mdc efforts proved successful standard complete 1974 approved september 15 1977 ansi standard x11.1-1977 time dec launched dsm-11 digital standard mumps pdp-11 quickly dominated market became reference implementation time also intersystems sold ism-11 pdp-11 identical dsm-11 early 1980s several vendors brought mumps-based platforms met ansi standard market significant companies developed important mumps implementations period also saw considerable mdc activity second revision ansi standard mumps x11.1-1984 approved november 15 1984 us department veterans affairs formerly veterans administration one earliest major adopters mumps language development work subsequent contributions free mumps application codebase influence many medical users worldwide 1995 veterans affairs patient admission/tracking/discharge system decentralized hospital computer program dhcp recipient computerworld smithsonian award best use information technology medicine july 2006 department veterans affairs va veterans health administration vha recipient innovations american government award presented ash institute john f. kennedy school government harvard university extension dhcp veterans health information systems technology architecture vista nearly entire va hospital system united states indian health service major parts department defense chcs hospital system use mumps databases clinical data tracking 2015 department defense awarded 10 year contract leidos cerner accenture replace chcs 2017 veterans health administration vha announced would replace vista cerner 2024 2025 2019 vha announced would also replace epic systems online appointment scheduling system one cerner 2024 healthcare companies using mumps include epic meditech ge healthcare formerly idx systems centricity ameripath part quest diagnostics care centric allscripts coventry healthcare emis sunquest information systems formerly misys healthcare many reference laboratories dasa quest diagnostics dynacare use mumps software written based antrim corporation code antrim purchased misys healthcare sunquest information systems 2001 mumps also widely used financial applications mumps gained early following financial sector use many banks credit unions used ameritrade largest online trading service us 12 billion transactions per day well bank england barclays bank among others since 2005 use mumps either form gt.m intersystems caché latter aggressively marketed intersystems success penetrating new markets telecommunications addition existing markets european space agency announced may 13 2010 use intersystems caché database support gaia mission mission aims map milky way unprecedented precision mumps language intended designed build database applications secondary language features included help programmers make applications using minimal computing resources original implementations interpreted though modern implementations may fully partially compiled individual programs run memory partitions early mumps memory partitions limited 2048 bytes aggressive abbreviation greatly aided multi-programming severely resource limited hardware one mumps job could fit small memories extant hardware time ability provide multi-user systems another language design feature word multi-programming acronym points even earliest machines running mumps supported multiple jobs running time change mini-computers micro-computers years later even single user pc single 8-bit cpu 16k 64k memory could support multiple users could connect non-graphical video display terminals since memory tight originally language design mumps valued terse code thus every mumps command function name could abbreviated one three letters length e.g quit exit program q p piece function r read command tr translate function spaces end-of-line markers significant mumps line scope promoted terse language design thus single line program code could express characters idea programming languages could require 5 10 times many characters abbreviation common feature languages designed period e.g. focal-69 early basics tiny basic etc. unfortunate side effect coupled early need write minimalist code mumps programmers routinely comment code used extensive abbreviations meant even expert mumps programmer could skim page code see function would analyze line line database interaction transparently built language mumps language provides hierarchical database made persistent sparse arrays implicitly opened every mumps application variable names prefixed caret character use permanent instead ram storage maintain values application exits visible modifiable running applications variables using shared permanent storage called globals mumps scoping variables globally available jobs system recent common use name global variables languages limited scoping names coming fact unscoped variables globally available programs running process shared among multiple processes mumps storage mode i.e globals stored persistent sparse arrays gives mumps database characteristics document-oriented database variable names prefixed caret character temporary private like global variables also hierarchical storage model locally available single job thus called locals globals locals child nodes called subscripts mumps terminology subscripts limited numerals—any ascii character group characters subscript identifier uncommon modern languages perl javascript highly unusual feature late 1970s capability universally implemented mumps systems 1984 ansi standard canonically numeric subscripts required standard allowed thus variable named 'car subscripts door steering wheel engine contain value subscripts variable ^car door could nested variable subscript color example thus could say modify nested child node ^car mumps terms color 2nd subscript variable ^car names child-nodes child-nodes likewise called subscripts hierarchical variables similar objects properties many object oriented languages additionally mumps language design requires subscripts variables automatically kept sorted order numeric subscripts including floating-point numbers stored lowest highest non-numeric subscripts stored alphabetical order following numbers mumps terminology canonical order using non-negative integer subscripts mumps programmer emulate arrays data type languages although mumps natively offer full set dbms features mandatory schemas several dbms systems built top provide application developers flat-file relational network database features additionally built-in operators treat delimited string e.g. comma-separated values array early mumps programmers would often store structure related information delimited string parsing read saved disk access time offered considerable speed advantages hardware mumps data types numbers treated strings digits strings treated numbers numeric operators coerced mumps terminology coercion odd side effects however example string coerced parser turns much string starting left number discards rest thus statement codice_1 evaluated codice_2 mumps features language intended help mumps applications interact multi-user environment database locks process identifiers atomicity database update transactions required standard mumps implementations contrast languages c wirth traditions space characters mumps statements significant single space separates command argument space newline separates argument next mumps token commands take arguments e.g. codice_3 require two following spaces concept one space separates command nonexistent argument next separates argument next command newlines also significant codice_4 codice_3 codice_6 command processes skips everything else till end-of-line make statements control multiple lines must use codice_7 command create code block simple hello world program mumps might would run mumps command line command codice_8 since mumps allows commands strung together line since commands abbreviated single letter routine could made compact 'codice_9 text generates newline ansi x11.1-1995 gives complete formal description language annotated version standard available online data types one universal datatype implicitly coerced string integer floating-point datatypes context requires booleans called truthvalues mumps commands syntax expressions evaluated conditions string value evaluated numeric value nonzero value interpreted true codice_10 yields 1 less b 0 otherwise declarations none variables dynamically created first time value assigned lines important syntactic entities unlike status languages patterned c pascal multiple statements per line allowed common scope else command remainder current line case sensitivity commands intrinsic functions case-insensitive contrast variable names labels case-sensitive special meaning upper vs. lower-case widely followed conventions percent sign legal first character variables labels postconditionals execution almost command controlled following colon truthvalue expression codice_11 sets foo n less 10 codice_12 performs printerr n greater 100 construct provides conditional whose scope less full line abbreviation abbreviate nearly commands native functions one two three characters reserved words none since mumps interprets source code context need reserved words may use names language commands variables following perfectly legal mumps code mumps made obfuscated using contracted operator syntax shown terse example derived example arrays created dynamically stored b-trees sparse i.e use almost space missing nodes use number subscripts subscripts strings numeric including floating point arrays always automatically stored sorted order never occasion sort pack reorder otherwise reorganize database built functions data order next deprecated query functions provide efficient examination traversal fundamental array structure disk memory local arrays variable names beginning caret i.e stored memory process private creating process expire creating process terminates available storage depends implementation implementations using partitions limited partition size small partition might 32k implementations may several megabytes global arrays codice_13 stored disk available processes persistent creating process terminates large globals example hundreds gigabytes practical efficient implementations mumps main database mechanism used instead calling operating system create write read files indirection many contexts codice_14 used effectively substitutes contents vbl another mumps statement codice_15 sets variable abc 123. codice_16 performs subroutine named report substitution allows lazy evaluation late binding well effectively operational equivalent pointers languages piece function breaks variables segmented pieces guided user specified separator string sometimes called delimiter know awk find familiar codice_17 means third caret-separated piece stringvar piece function also appear assignment set command target codice_18 yields std codice_19 causes x become office world.std.com note p equivalent piece could written order function function treats input structure finds next index exists structure except last subscript returns sorted value ordered one given input treats array reference content-addressable data rather address value codice_20 yields 6 codice_21 yields 10 codice_22 yields 10 codice_23 yields 15 codice_24 yields argument-less repeats stopped terminating quit line prints table stuff successively 6 10 15 iterating database order function returns next key use multi-user/multi-tasking/multi-processor mumps supports multiple simultaneous users processes even underlying operating system e.g. ms-dos additionally ability specify environment variable specifying machine name variable codice_25 allow access data remote machines aspects mumps syntax differ strongly modern languages cause confusion whitespace allowed within expressions ends statement codice_26 error must written codice_27 operators precedence left-associative codice_28 evaluates 50 operators less equal greater equal codice_29 codice_30 boolean negation operator codice_31 plus strict comparison operator periods codice_32 used indent lines block whitespace else command need corresponding operates inspecting value builtin system variable codice_33 mumps scoping rules permissive modern languages declared local variables scoped using stack routine normally see declared locals routines call stack routines prevent routines call modifying declared locals contrast undeclared variables variables created using rather declaration scope routines running process remain scope program exits following positions supported knowledgeable people various times contention arose response strong advocacy part one commercial interest intersystems whose chief executive disliked name mumps felt represented serious marketing obstacle thus favoring extent became identified alignment intersystems dispute also reflected rivalry organizations technology association mumps development committee ansi iso standards committees determines official name language writers attempted defuse issue referring language umps square brackets customary notation optional syntax elements leading authority author open source mumps implementation professor kevin o'kane uses 'mumps recent standard iso/iec 11756:1999 re-affirmed 25 june 2010 still mentions mumps officially accepted names massachusetts general hospital registered mumps trademark uspto november 28 1971 renewed november 16 1992 let expire august 30 2003 mumps invites comparison pick operating system similarities include
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Programming language topics
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allwinner a1x allwinner a1x family single-core soc devices designed allwinner technology zhuhai china currently family consists a10 a13 a10s a12 socs incorporate arm cortex-a8 main processor mali 400 gpu allwinner a1x known ability boot linux distributions debian ubuntu fedora arm architecture-capable distributions sd card addition android os usually installed flash memory device video acceleration display controller memory connectivity storage boot devices many manufacturers adopted allwinner a1x use devices running android operating system linux operating system allwinner a1x used tablet computers set-top boxes pc-on-a-stick mini-pcs single-board computers allwinner a1x architecture referred 'sunxi linux kernel source tree source code available github moment stable full hardware support limited 3.0.x 3.4.x kernels recent mainline versions kernel run offer nand access limited 3d-acceleration work progress support efika freebsd moment on-board peripherals working may 2015 openbsd armv7 port supports cubieboard pcduino boards based allwinner a1x netbsd contains support allwinner a10 factory sourced programmers manual publicly available a10s cpu moment apart single-core a1x a10/a13/a10s/a12 two new powerful cortex-a7 allwinner socs released allwinner a10-pin-compatible dual-core allwinner a20 quad-core allwinner a31
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Computer architecture
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domain technologie control domain technologie control dtc web hosting control panel aimed providing graphics-oriented layout managing commercial hosting web servers intended shared web hosting servers virtual private servers vpses dedicated servers domain technologie control free software released gnu lgpl v2.1 license fully skinnable translated several languages domain technologie control allows administrator create web hosting plans provide e-mail ftp accounts domain purchasing subdomains ssh mysql databases end users controllable quota web sites users dtc also maintains automation billing generates backup scripts monitors traffic per user per service using single system uid gid also integrated dtc support ticket system customizable http error pages dtc manages mysql database store setup configuration web hosting plans users support many free software mysql apache php qmail postfix courier dovecot proftpd webalizer mod-log-sql also connects dtc-xen manage monitor usage virtual private servers vps dtc fully open source lgpl dtc also first web hosting control panel reached inclusion major distributions like debian since lenny 2009 ubuntu since 2008 freebsd
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Internet protocols
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star soldier video game mobile versions released january 26 2001 japan star soldier special+ 2004 star soldier sp arcade 2005 2008 're also released palm os november 2001 japan ios january 4 2012 united states star soldier spawned numerous sequels starting super star soldier pc engine ported game boy advance 2004 japan part famicom mini series wii virtual console japanese north american regions july 2007 enhanced remake game released playstation portable japan 2005 3ds virtual console re-released konami november 14 2012 japan august 15 2013 pal version september 24 2013 north america ios version titled june 20 2013 japan
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Computer architecture
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referential integrity referential integrity property data stating references valid context relational databases requires value one attribute column relation table references value another attribute either different relation referenced value must exist referential integrity hold relational database column base table declared foreign key contain either null values values parent table primary key candidate key words foreign key value used must reference valid existing primary key parent table instance deleting record contains value referred foreign key another table would break referential integrity relational database management systems rdbms enforce referential integrity normally either deleting foreign key rows well maintain integrity returning error performing delete method used may determined referential integrity constraint defined data dictionary adjective 'referential describes action foreign key performs 'referring linked column another table simple terms 'referential integrity guarantees target 'referred found lack referential integrity database lead relational databases return incomplete data usually indication error inclusion dependency two possibly identical predicates formula_1 formula_2 schema written formula_3 formula_4 formula_5 distinct attributes column names formula_1 formula_2 implies tuples values appearing columns formula_8 facts formula_1 must also appear tuple values columns formula_10 fact formula_2 logical implication inclusion dependencies axiomatized inference rules decided pspace algorithm problem shown pspace-complete reduction acceptance problem linear bounded automaton however logical implication dependencies inclusion dependencies functional dependencies undecidable reduction word problem monoids declarative referential integrity dri one techniques sql database programming language ensure data integrity table called referencing table refer column group columns another table referenced table using foreign key referenced column referenced table must unique constraint primary key also self-references possible fully implemented ms sql server though inserting new row referencing table relational database management system rdbms checks entered key value exists referenced table insert possible also possible specify dri actions update delete cascade forwards change/delete referenced table referencing tables action specific row referenced changing key allowed set null set default changed/deleted key referenced table results setting referencing values null default value one specified ansi/iso/iec 9075-1:2003 information technology—database languages—sql—part 1 framework sql/framework ansi/iso/iec 9075-2:2003 information technology—database languages—sql—part 2 foundation sql/foundation microsoft sql server term dri also applies assigning permissions users database object giving dri permission database user allows add foreign key constraints table
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Databases
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totalrecovery totalrecovery backup recovery software product developed farstone technology formerly known driveclone totalrecovery written c++ runs microsoft windows 32-bit 64-bit utility utilizes windows preinstallation environment allows users administer tasks loading operating system totalrecovery comes two editions express edition professional edition express edition requires installation fewer features compared professional edition
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Computer security
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floppyfw floppyfw linux distribution running busybox provide firewall/gateway/router single bootable floppy disk later available cd format reviews concluded simple reliable gateway/firewall could established small medium-sized networks low cost ease.. one independent study concluded best possible security provided floppy-based firewall repurposing old redundant hardware linux-based firewalls routers floppyfw features include
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Operating systems
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internal field separator many command line interpreters “ shell ” unix operating systems internal field separator abbreviated ifs refers variable defines character characters used separate pattern tokens operations ifs typically includes space tab newline bash man page shell treats character ifs delimiter splits results expansions words characters ifs unset value exactly space tab newline default sequences space tab newline beginning end results previous expansions ignored sequence ifs characters beginning end serves delimit words ifs value default sequences whitespace characters space tab ignored beginning end word long whitespace character value ifs ifs whitespace character character ifs ifs whitespace along adjacent ifs whitespace characters delimits field sequence ifs whitespace characters also treated delimiter value ifs null word splitting occurs ifs usable exploit versions unix program root permissions could fooled executing user-supplied code ran instance codice_1 called ifs set case would run program bin current directory thus writable user root permissions fixed making shells inherit ifs variable examples apply use ifs bash scripts
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Operating systems
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national cyber security awareness month national cyber security awareness month ncsam observed october united states america started national cyber security division within department homeland security nonprofit national cyber security alliance month raises awareness importance cybersecurity 2004 department homeland security national cyber security alliance launched national cyber security awareness month broad effort help americans stay safe secure online initial efforts included advice like keeping antivirus programs date since 2009 month included overall theme shared responsibility weekly themes throughout month introduced 2011
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Computer security
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byzantine fault byzantine fault also interactive consistency source congruency error avalanche byzantine agreement problem byzantine generals problem byzantine failure condition computer system particularly distributed computing systems components may fail imperfect information whether component failed term takes name allegory byzantine generals problem developed describe condition actors must agree concerted strategy avoid catastrophic system failure actors unreliable byzantine fault component server inconsistently appear failed functioning failure-detection systems presenting different symptoms different observers difficult components declare failed shut network need first reach consensus regarding component failed first place byzantine fault tolerance bft dependability fault-tolerant computer system conditions byzantine fault fault presenting different symptoms different observers byzantine failure loss system service due byzantine fault systems require consensus objective byzantine fault tolerance able defend failures system components without symptoms prevent components system reaching agreement among agreement needed correct operation system remaining correctly operational components byzantine fault tolerant system able continue providing system service originally intended assuming sufficiently many accurately operating components maintain service byzantine failures considered general difficult class failures among failure modes so-called fail-stop failure mode occupies simplest end spectrum whereas fail-stop failure mode simply means way fail node crash detected nodes byzantine failures imply restrictions means failed node generate arbitrary data pretending correct one thus byzantine failures confuse failure detection systems makes fault tolerance difficult despite analogy byzantine failure necessarily security problem involving hostile human interference arise purely electrical faults terms fault failure used according standard definitions originally created joint committee fundamental concepts terminology formed ieee computer society technical committee dependable computing fault-tolerance ifip working group 10.4 dependable computing fault tolerance version definitions also described dependability wikipedia page problem obtaining byzantine consensus conceived formalized robert shostak dubbed interactive consistency problem work done 1978 context nasa-sponsored sift project computer science lab sri international sift software implemented fault tolerance brain child john wensley based idea using multiple general-purpose computers would communicate pairwise messaging order reach consensus even computers faulty beginning project clear many computers total needed guarantee conspiracy n faulty computers could thwart efforts correctly-operating ones reach consensus shostak showed minimum 3 n+ 1 needed devised two-round 3 n+1 messaging protocol would work n =1 colleague marshall pease generalized algorithm n 0 proving 3 n +1 necessary sufficient results together later proof leslie lamport sufficiency 3 n using digital signatures published seminal paper reaching agreement presence faults authors awarded 2005 edsger w. dijkstra prize paper make interactive consistency problem easier understand lamport devised colorful allegory group army generals formulate plan attacking city original version story cast generals commanders albanian army name changed eventually settling byzantine suggestion jack goldberg future-proof potential offense giving formulation problem together additional results presented authors 1982 paper byzantine generals problem simplest form generals must decide whether attack retreat generals may prefer attack others prefer retreat important thing every general agrees common decision halfhearted attack generals would become rout would worse either coordinated attack coordinated retreat problem complicated presence treacherous generals may cast vote suboptimal strategy may selectively instance nine generals voting four support attacking four others favor retreat ninth general may send vote retreat generals favor retreat vote attack rest received retreat vote ninth general retreat rest attack may go well attackers problem complicated generals physically separated send votes via messengers may fail deliver votes may forge false votes byzantine fault tolerance achieved loyal non-faulty generals majority agreement strategy default vote value given missing messages example missing messages given value null agreement null votes majority pre-assigned default strategy used e.g. retreat typical mapping story onto computer systems computers generals digital communication system links messengers although problem formulated analogy decision-making security problem electronics solved simply cryptographic digital signatures failures incorrect voltages propagate encryption process thus component may appear functioning one component faulty another prevents forming consensus whether component faulty several examples byzantine failures occurred given two equivalent journal papers examples described nasa dashlink web pages web pages also describe phenomenology cause byzantine faults byzantine errors observed infrequently irregular points endurance testing newly constructed virginia class submarines least 2005 issues publicly reported several solutions described lamport shostak pease 1982 began noting generals problem reduced solving commander lieutenants problem loyal lieutenants must act unison action must correspond commander ordered case commander loyal several system architectures designed c. 1980 implemented byzantine fault tolerance include draper ftmp honeywell mmfcs sri sift 1999 miguel castro barbara liskov introduced practical byzantine fault tolerance pbft algorithm provides high-performance byzantine state machine replication processing thousands requests per second sub-millisecond increases latency pbft several bft protocols introduced improve robustness performance instance q/u hq zyzzyva abstracts addressed performance cost issues whereas protocols like aardvark rbft addressed robustness issues furthermore adapt tried make use existing bft protocols switching adaptive way improve system robustness performance underlying conditions change furthermore bft protocols introduced leverage trusted components reduce number replicas e.g. a2m-pbft-ea minbft one example bft use bitcoin peer-to-peer digital cash system bitcoin network works parallel generate blockchain proof-of-work allowing system overcome byzantine failures reach coherent global view system state aircraft systems boeing 777 aircraft information management system via arinc 659 safebus network boeing 777 flight control system boeing 787 flight control systems use byzantine fault tolerance real-time systems byzantine fault tolerance solutions must low latency example safebus achieve byzantine fault tolerance within order microsecond added latency spacecraft flight systems spacex dragon consider byzantine fault tolerance design byzantine fault tolerance mechanisms use components repeat incoming message signature recipients incoming message mechanisms make assumption act repeating message blocks propagation byzantine symptoms systems high degree safety security criticality assumptions must proven true acceptable level fault coverage providing proof testing one difficulty creating sufficiently wide range signals byzantine symptoms testing likely require specialized fault injectors
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Computer architecture
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kepler microarchitecture kepler codename gpu microarchitecture developed nvidia first introduced retail april 2012 successor fermi microarchitecture kepler nvidia first microarchitecture focus energy efficiency geforce 600 series geforce 700 series geforce 800m series gpus based kepler manufactured 28 nm kepler also found use gk20a gpu component tegra k1 soc well quadro kxxx series quadro nvs 510 nvidia tesla computing modules kepler followed maxwell microarchitecture used alongside maxwell geforce 700 series geforce 800m series architecture named johannes kepler german mathematician key figure 17th century scientific revolution goal nvidia previous architecture design focused increasing performance compute tessellation kepler architecture nvidia targeted focus efficiency programmability performance efficiency aim achieved use unified gpu clock simplified static scheduling instruction higher emphasis performance per watt abandoning shader clock found previous gpu designs efficiency increased even though requires additional cores achieve higher levels performance cores power-friendly two kepler cores using 90 power one fermi core according nvidia numbers also change unified gpu clock scheme delivers 50 reduction power consumption area programmability aim achieved kepler hyper-q dynamic parallelism multiple new compute capabilities 3.x functionality higher gpu utilization simplified code management achievable gk gpus thus enabling flexibility programming kepler gpus finally performance aim additional execution resource cuda core register cache kepler ability achieve memory clock speed 6 ghz increases kepler performance compare previous nvidia gpus gk series gpu contains features older fermi newer kepler generations kepler based members add following standard features kepler architecture employs new streaming multiprocessor architecture called smx smxs reason kepler power efficiency whole gpu uses single unified clock speed although smxs usage single unified clock increases power efficiency due fact multiple lower clock kepler cuda cores consume 90 less power multiple higher clock fermi cuda core additional processing units needed execute whole warp per cycle doubling 16 32 per cuda array solve warp execution problem smx front-end also double warp schedulers dispatch unit register file doubled 64k entries feed additional execution units risk inflating die area smx polymorph engines enhanced 2.0 rather double alongside execution units enabling spurr polygon shorter cycles dedicated fp64 cuda cores also used kepler cuda cores fp64 capable save die space improvement nvidia made smx results include increase gpu performance efficiency gk110 48kb texture cache unlocked compute workloads compute workload texture cache becomes read-only data cache specializing unaligned memory access workloads furthermore error detection capabilities added make safer workloads rely ecc register per thread count also doubled gk110 255 registers per thread additional die spaces acquired replacing complex hardware scheduler simple software scheduler software scheduling warps scheduling moved nvidia compiler gpu math pipeline fixed latency introduced instruction-level parallelism addition thread level parallelism instructions statically scheduled consistency introduced moving fixed latency instructions static scheduled compiler removed level complexity gpu boost new feature roughly analogous turbo boosting cpu gpu always guaranteed run minimum clock speed referred base clock clock speed set level ensure gpu stays within tdp specifications even maximum loads loads lower however room clock speed increased without exceeding tdp scenarios gpu boost gradually increase clock speed steps gpu reaches predefined power target 170 w default taking approach gpu ramp clock dynamically providing maximum amount speed possible remaining within tdp specifications power target well size clock increase steps gpu take adjustable via third-party utilities provide means overclocking kepler-based cards nvidia fermi kepler gpus geforce 600 series support direct3d 11.0 specification nvidia originally stated kepler architecture full directx 11.1 support includes direct3d 11.1 path following modern ui direct3d 11.1 features however supported ref name= nvidia/d3d11.1 /ref according definition microsoft direct3d feature level 11_1 must complete otherwise direct3d 11.1 path executed integrated direct3d features kepler architecture geforce 400 series fermi architecture nvidia kepler gpus geforce 600/700 series support direct3d 12 feature level 11_0 exclusive kepler gpus txaa new anti-aliasing method nvidia designed direct implementation game engines txaa based msaa technique custom resolve filters designed address key problem games known shimmering temporal aliasing txaa resolves smoothing scene motion making sure in-game scene cleared aliasing shimmering low level gk110 sees additional instructions operations improve performance new shuffle instructions allow threads within warp share data without going back memory making process much quicker previous load/share/store method atomic operations also overhauled speeding execution speed atomic operations adding fp64 operations previously available fp32 data hyper-q expands gk110 hardware work queues 1 32 significance single work queue meant fermi could occupied times n't enough work queue fill every sm 32 work queues gk110 many scenarios achieve higher utilization able put different task streams would otherwise idle smx simple nature hyper-q reinforced fact easily mapped mpi common message passing interface frequently used hpc legacy mpi-based algorithms originally designed multi-cpu systems became bottlenecked false dependencies solution increasing number mpi jobs possible utilize hyper-q algorithms improve efficiency without changing code dynamic parallelism ability kernels able dispatch kernels fermi cpu could dispatch kernel incurs certain amount overhead communicate back cpu giving kernels ability dispatch child kernels gk110 save time go back cpu process free cpu work tasks enabling dynamic parallelism requires new grid management dispatch control system new grid management unit gmu manages prioritizes grids executed gmu pause dispatch new grids queue pending suspended grids ready execute providing flexibility enable powerful runtimes dynamic parallelism cuda work distributor kepler holds grids ready dispatch able dispatch 32 active grids double capacity fermi cwd kepler cwd communicates gmu via bidirectional link allows gmu pause dispatch new grids hold pending suspended grids needed gmu also direct connection kepler smx units permit grids launch additional work gpu via dynamic parallelism send new work back gmu prioritized dispatched kernel dispatched additional workload pauses gmu hold inactive dependent work completed nvidia gpudirect capability enables gpus within single computer gpus different servers located across network directly exchange data without needing go cpu/system memory rdma feature gpudirect allows third party devices ssds nics ib adapters directly access memory multiple gpus within system significantly decreasing latency mpi send receive messages to/from gpu memory also reduces demands system memory bandwidth frees gpu dma engines use cuda tasks kepler gk110 also supports gpudirect features including peer‐to‐peer gpudirect video nvenc nvidia power efficient fixed-function encode able take codecs decode preprocess encode h.264-based content nvenc specification input formats limited h.264 output still nvenc limited format support 4096x4096 encode like intel quick sync nvenc currently exposed proprietary api though nvidia plans provide nvenc usage cuda theoretical single-precision processing power kepler gpu gflops computed 2 operations per fma instruction per cuda core per cycle × number cuda cores × core clock speed ghz note like previous generation fermi kepler able benefit increased processing power dual-issuing mad+mul like tesla capable theoretical double-precision processing power kepler gk110/210 gpu 1/3 single precision performance double-precision processing power however available professional quadro tesla high-end titan-branded geforce cards drivers consumer geforce cards limit performance 1/24 single precision performance lower performance gk10x chips similarly capped 1/24 single precision performance
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Computer architecture
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chntpw chntpw software utility resetting blanking local passwords used windows nt 2000 xp vista 7 8 8.1 10 editing sam database windows stores password hashes two ways use program via standalone chntpw utility installed package available modern linux distributions e.g ubuntu via bootable cd/usb image also floppy release support dropped chntpw support fully encrypted ntfs partitions possible exceptions encrypted partitions readable linux e.g luks usernames containing unicode characters active directory passwords exception local users systems members ad domain password changing feature also n't fully functional either password blanking highly recommended fact latter versions windows possible option furthermore bootable image might problems controllers requiring 3rd party drivers cases use stand-alone program full-featured linux environment recommended codice_1 utility included many various linux distributions including ones focused security software 10th anniversary author changed license non-commercial one gnu general public license gpl version 2
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Operating systems
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xcopy computing codice_1 command used ibm pc dos ms-dos ibm os/2 microsoft windows freedos reactos related operating systems copying multiple files entire directory trees one directory another copying files across network codice_1 stands extended copy created functional file copying utility codice_3 command found earlier operating systems codice_1 first appeared dos 3.2 still included windows 10 codice_1 deprecated favor codice_6 powerful copy tool built microsoft windows server desktop operating systems dr dos 6.0 includes implementation command freedos version developed rene ableidinger licensed gpl j. edmeades developed wine-compatible version included reactos licensed lgpl create new directory copying contents existing directory including files subdirectories hidden system attributes empty directories directory names include blank signs spaces names put quotation marks copy entire drive mapped network drive ignoring errors network restartable mode copy single file without prompt file directory codice_1 fails insufficient memory error path plus filename longer 254 characters moving large files without /j option available server 2008r2 consume available ram system codice_1 copy open files process may open files exclusive read access withholding file_share_read https //msdn.microsoft.com/en-us/library/aa363858.aspx windows volume shadow copy service used situations codice_1 use therefore codice_1 useful backing live operating system volumes
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Computer file systems
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credant technologies credant technologies company located addison texas offering products services data security company founded 2001 bob heard chris burchett andrew kahl company offers range products protect data leaking several different versions main technology used different locations network via policy proxy border lan internet dmz central enterprise server within network also editions exchange servers domain controllers available products self-encrypting drivers encrypt data drive without additional requirements client user bitlocker management systems policy reporting tools company claims products protect two million end-points several industries universities health-care aeronautical financial government/defense 18 december 2012 dell announced reached agreement credant would acquire company prior acquisition dell already technology partner credant dell bought 16 companies past 4 years several directly indirectly field data-security major step field security services made dell start 2011 acquired secureworks 2012 acquisition sonicwall best known firewalls intrusion detection prevention appliances also companies dell bought past years offer products services security including perot systems quest software acquisition credant dell gambles continuation strong growth security services
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Computer security
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national industrial security program national industrial security program nisp nominal authority united states managing needs private industry access classified information nisp established 1993 executive order 12829 national security council nominally sets policy nisp director information security oversight office nominally authority implementation isoo secretary defense nominally executive agent nisp recognizes four different cognizant security agencies equal authority department defense department energy central intelligence agency nuclear regulatory commission major component nisp nisp operating manual also called nispom dod 5220.22-m nispom establishes standard procedures requirements government contractors regards classified information current nispom edition dated 28 feb 2006 chapters selected sections edition dod 5220.22-m sometimes cited standard sanitization counter data remanence nispom actually covers entire field government–industrial security data sanitization small part two paragraphs 141-page document furthermore nispom actually specify particular method standards sanitization left cognizant security authority defense security service provides clearing sanitization matrix c sm specify methods june 2007 edition dss c sm overwriting longer acceptable sanitization magnetic media degaussing physical destruction acceptable
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Computer security
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resource exhaustion attack resource exhaustion attacks computer security exploits crash hang otherwise interfere targeted program system form denial-of-service attack different distributed denial-of-service attacks involve overwhelming network host web server requests many locations resource exhaustion attacks generally exploit software bug design deficiency software manual memory management commonly written c c++ memory leaks common bug exploited resource exhaustion even garbage collected programming language used resource exhaustion attacks possible program uses memory inefficiently impose limits amount state used necessary file descriptor leaks another common vector general-purpose programming languages require programmer explicitly close file descriptors even particularly high-level languages allow programmer make mistakes
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Computer security
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callfire callfire inc. cloud telephony services provider saas headquartered santa monica california known locally silicon beach callfire develops web-based voip products services business-to-business b2b service small medium-sized businesses smb company incorporated 2004 dinesh ravishanker vijesh mehta komnieve singh punit shah tj thinakaran came board 2006 2007 respectively round founding team dan retzlaff james nguyen shane neman hired initial years ronald burr hired spring 2012 company provides cloud communication services voice broadcasting power dialing interactive voice response 2010 callfire ranked 285 inc. magazine ’ 29th annual list america ’ fastest growing private companies callfire ranked 15 within telecommunications industry los angeles metropolitan region much callfire ’ annual growth attributed “ growth calls use service u.s. elections well hurricane sandy ”
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Distributed computing architecture
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arcs computing arcs firmware bootloader also known prom console used computers produced sgi since beginning 1990s arcs system loosely compliant advanced risc computing arc standard promulgated advanced computing environment consortium early 1990s another sense arc standard based sgi arcs used basis generating arc standard although arc calls little-endian system arcs system big-endian mips-based systems despite various inconsistencies two sgi arcs implementations arc standard share many commonalities device naming calling conventions etc. computers use arcs firmware based mips line microprocessors sgi visual workstation series based intel pentium iii also uses arcs visual workstation series commercially produced x86-compatible system used arcs firmware rather traditional pc bios used intel 386-lineage machines list product lines use arcs console includes
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Computer architecture
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metro ring protocol metro ring protocol mrp layer 2 resilience protocol developed foundry networks currently delivered products manufactured brocade communications systems hewlett packard protocol quite tightly specifies topology layer 2 devices usually core larger network configured able achieve much faster failover times layer 2 protocols spanning tree
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Internet protocols
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roger wilco software roger wilco one first voice-over-ip client programs designed primarily use online multiplayer video games roger wilco enabled online gamers talk one another computer headset audio input device instead typing messages within year software introduction 2 million online video gamers flocked application roger wilco procedure words radiophone communication mean understood message comply roger wilco developed us startup company called resounding technology three company four founders roommates undergraduate students princeton university adam frankl tony lovell henri de marcellus david lewis led marketing business development based silicon valley responsible growing roger wilco community managed partnerships video game publishers bundled roger wilco games plantronics pny game peripheral manufacturers also bundled roger wilco products company began publishing pre-release versions software autumn 1998 first general availability release roger wilco mark followed may 1999 company distributed client server freeware server software roger wilco base station developed linux freebsd windows 9x windows nt development client mac os never progressed beyond alpha phase david lewis demonstrated product server-less voice capabilities mpath interactive startup company silicon valley went acquire resounding technology based proprietary peer-to-peer voice technology company ipo 'd soon renamed hearme inc december 2000 gamespy bought roger wilco intellectual property early 2001 integrated updated version client software game server browser gamespy arcade players could use roger wilco software bought subscription gamespy game tools suite david lewis licensed sdk versions voice technology virtually every major game publisher including activision ea microsoft ubisoft others licensing arrangement microsoft enabled use voice sdk microsoft xbox required multi-player xbox game developers included in-game voice chat capabilities today virtually every leading online multiplayer game includes voicechat due pioneering efforts resounding team gamespy published final version roger wilco client windows july 8 2003 year vice president consumer products gamespy industries told boston globe roger wilco 5 million users
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Internet protocols
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lookout security lookout private security company headquartered san francisco california develops markets cloud-based security software mobile devices company founded 2007 three security researchers previously consulting name flexilis years raised 300 million venture capital funding lookout also expanded consumer android app mobile devices operating systems business version lookout founded three security researchers met university southern california los angeles students formed consulting firm focused cybersecurity called flexilis 2003 2004 discovered vulnerability nokia phones allowed take control phones remotely bluetooth founders could n't get nokia patch vulnerability scanned data nokia phones 2005 academy awards using high-powered bluetooth device publicity stunt exposing security vulnerabilities private phones celebrities led widespread media attention nokia soon fixed problem 2007 flexilis began developing mobile security app raised 5.5 million venture capital 2009 flexilis changed name lookout 11 million venture capital funding raised 2010 followed 40 million 2011 75 million 2012 55 million 2013 series f funding round 2014 raised another 150 million funding 2014 co-founder john hering stepped ceo former juniper networks executive jim dolce appointed position 2017 lookout citizen lab discovered malicious app called pegasus made israeli-firm nso group iphone android versions posed ordinary apps took control phone downloaded following year lookout electronic frontier foundation published report exposing series similar hacking campaigns lebanese government called dark caracal lookout develops markets security app mobile phones also called lookout free version includes antivirus antimalware scans locator features free version comes pre-installed android devices sold t-mobile sprint paid versions add ability remotely lock wipe phone backup photos features enterprise version adds analytics admin console tools detect malicious software corporate networks first free version lookout introduced december 2009 first paid version introduced following year safe browsing browser add-on added 2011 2012 version 3 lookout overhauled user interface added signal flare documents phone location runs battery following year lookout added feature secretly takes photo someone tries unlock phone unsuccessfully order catch thieves first business version added features administrators introduced 2013 followed first enterprise version june 2015
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Computer security
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intel advisor intel advisor also known advisor xe vectorization advisor threading advisor simd vectorization optimization shared memory threading assistance tool c c++ c fortran software developers architects product available windows linux operating systems form standalone gui tool microsoft visual studio plug-in command line interface also supporting usage mpi intel advisor incorporates two workflows two feature-sets vectorization advisor threading advisor vectorization advisor supports analysis scalar sse avx avx2 avx-512-enabled codes generated intel gnu microsoft compilers auto-vectorization also supports analysis explicitly vectorized codes use openmp 4.x intel cilk plus well codes written using c vector intrinsics assembly language intel advisor includes following main features vectorization advisor capability introduced 2016 release intel advisor works compilers gcc microsoft provide additional information used intel compilers version 15.x newer examples include vectorize vector efficiency metrics intel advisor available part intel parallel studio xe vectorization advisor part intel advisor 2016 supports native analysis 2nd generation intel® xeon phi™ codenamed knights landing processor starting intel advisor 2016 update 3 version advisor survey map analysis several avx-512-specific tuning capabilities advisor also separate capability analysis non-executed code paths analyze avx-512 code characteristics running analysis platforms n't support avx-512 intel advisor automates roofline performance model first proposed berkeley extended university lisbon advisor roofline analysis helps identify given loop/function memory cpu bound also identifies optimized loops high impact performance optimized public sources known used schlumberger sandia national lab well leading design company classified great timesaver incredibly useful tool supporting parallel algorithm research advisor also aims simplify speed-up parallel design implementation providing step-by-step workflow claimed useful academia educational purposes public sources new vectorization advisor capabilities introduced august 2015 known used lrz ichec daresbury lab pexip prototype threading designs software architects add code annotations describe threading understood advisor ignored compiler advisor projects scalability threading checks synchronization errors threading suitability projections intel xeon phi beginning 2015 release suitability analysis supported first generation intel xeon phi™ coprocessor knights corner threading performance scalability parallel runtimes overheads modeling suitability estimates intel® xeon phi™ processor peak performance given loop/workload automatically compares appropriate double-socket 16-core intel® xeon® reference performance baseline
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Operating systems
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vundo vundo trojan commonly known vundo virtumonde virtumondo sometimes referred ms juan either trojan horse computer worm known cause popups advertising rogue antispyware programs sporadically misbehavior including performance degradation denial service websites including google facebook also used deliver malware host computers later versions include rootkits ransomware vundo infection typically caused either opening e-mail attachment carrying trojan variety browser exploits including vulnerabilities popular browser plug-ins java many popups advertise fraudulent programs antispywaremaster winfixer antivirus 2009. codice_1 consists two main components browser helper objects class id components windows registry hkey local machine file names dynamic attaches system using bogus browser helper objects dll files attached winlogon.exe explorer.exe recently lsass.exe vundo inserts registry entries suppress windows warnings disabling firewall antivirus automatic updates service disables automatic updates service quickly re-disables manually re-enabled attacks malwarebytes anti-malware spybot search destroy lavasoft ad-aware hijackthis several malware removal tools frequently hides vundofix combofix rather pushing fake antivirus products new ad popups drive download attacks copies ads major corporations faked simply closing allows drive-by download exploit insert payload user computer since many different varieties vundo trojans symptoms vundo vary widely ranging relatively benign severe almost varieties vundo feature sort pop-up advertising well rooting make difficult delete computers infected exhibit following symptoms
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Computer security
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int 16h int 16h int 16h int 22 shorthand bios interrupt call 16hex 22nd interrupt vector x86-based computer system bios typically sets real mode interrupt handler vector provides keyboard services interruption responsible control pc keyboard interruption responsible obtaining basic keyboard functionality i.e responsible collecting keystrokes obtain status buffer keyboard etc standard encoding keyboard offers int 16 h us keyboard adapt coding int 16h another type keyboard example hebrew keyboard must attend scan-code key pressed perform suitable interpreting key want 101 letters keyboard keys int 16h interprets expanded keys scan-code different normal keys e.g. key pause
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Computer architecture
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jdbc driver jdbc driver software component enabling java application interact database jdbc drivers analogous odbc drivers ado.net data providers ole db providers connect individual databases jdbc java database connectivity api requires drivers database jdbc driver gives connection database implements protocol transferring query result client database jdbc technology drivers fit one four categories jdbc type 1 driver also known jdbc-odbc bridge database driver implementation employs odbc driver connect database driver converts jdbc method calls odbc function calls driver platform-dependent makes use odbc turn depends native libraries underlying operating system jvm running upon also use driver leads installation dependencies example odbc must installed computer driver database must support odbc driver use driver discouraged alternative pure-java driver available implication application using type 1 driver non-portable given binding driver platform technology n't suitable high-transaction environment type 1 drivers also n't support complete java command set limited functionality odbc driver sun oracle provided jdbc-odbc bridge driver codice_1 driver native code java closed source sun's/oracle jdbc-odbc bridge removed java 8 vendors available driver written loading causes instance created also calls codice_2 instance parameter drivermanager list drivers available creating connection may sometimes case one jdbc driver capable connecting given url example connecting given remote database might possible use jdbc-odbc bridge driver jdbc-to-generic-network-protocol driver driver supplied database vendor cases order drivers tested significant drivermanager use first driver finds successfully connect given url first drivermanager tries use driver order registered drivers listed jdbc.drivers always registered first skip drivers untrusted code unless loaded source code trying open connection tests drivers calling method driver.connect one turn passing url user originally passed method codice_3 first driver recognizes url makes connection jdbc type 2 driver also known native-api driver database driver implementation uses client-side libraries database driver converts jdbc method calls native calls database api example oracle oci driver type 2 driver jdbc type 3 driver also known pure java driver database middleware database driver implementation makes use middle tier calling program database middle-tier application server converts jdbc calls directly indirectly vendor-specific database protocol differs type 4 driver protocol conversion logic resides client middle-tier like type 4 drivers type 3 driver written entirely java client-side jdbc driver may used multiple databases depends number databases middleware configured support type 3 driver platform-independent platform-related differences taken care middleware also making use middleware provides additional advantages security firewall access jdbc type 4 driver also known direct database pure java driver database driver implementation converts jdbc calls directly vendor-specific database protocol written completely java type 4 drivers thus platform independent install inside java virtual machine client provides better performance type 1 type 2 drivers overhead conversion calls odbc database api calls unlike type 3 drivers need associated software work database protocol vendor specific jdbc client requires separate drivers usually vendor supplied connect different types databases
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Databases
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crash reporter crash reporter usually system software whose function identify reporting crash details alert crashes production development testing environments crash reports often include data stack traces type crash trends version software reports help software developers- web saas mobile apps diagnose fix underlying problem causing crashes crash reports may contain sensitive information passwords email addresses contact information become objects interest researchers field computer security implementing crash reporting tools part development cycle become standard crash reporting tools become commodity many offered free like crashlytics many giant industry players part software development eco-system entered game companies twitter google others putting lot efforts encouraging software developers use apis knowing increase revenues road advertisements mechanisms realize must offer elegant solutions many possible development issues otherwise competitors take actions keep adding advanced features crash reporting tools make important development functionality giant companies include portfolio solutions many crash reporting tools specialized mobile app many sdks macos standard crash reporter /system/library/coreservices/crash reporter.app crash reporter.app sends unix crash logs apple engineers look top text field window crash log bottom field user comments users may also copy paste log email client send application vendor use crash reporter.app 3 main modes display nothing crash display application crashed dialog box display crash report window microsoft windows includes crash reporting service called windows error reporting prompts users send crash reports microsoft online analysis information goes central database run microsoft consists diagnostic information helps company development team responsible crash debug resolve issue choose crash reports third party software available third party developers granted access microsoft system considers parts debug release process targeted bug fixes applied windows update words people experiencing particular type crash offered bug fix thus limiting exposure issue according der spiegel microsoft crash reporter exploited nsa tailored access operations tao unit hack computers mexico secretariat public security according source microsoft crash reports automatically harvested nsa xkeyscore database order facilitate operations another error reporting library windows crashrpt crashrpt library light-weight open source error handling framework applications created microsoft visual c++ running windows library distributed new bsd license crashrpt intercepts unhandled exceptions creates crash minidump file builds crash descriptor xml format presents interface allow user review crash report finally compresses sends crash report software support team crashrpt also provides server-side command line tool crash report analysis named crprober tool able read received crash reports directory generate summary file text format crash report also groups similar crash reports making easier determine popular problems crprober tool provide graphical interface rather cryptic difficult use also open-source server software named crashfix server store organize analyze crash reports sent crashrpt library group similar crash reports built-in bug tracker generate statistical reports crashfix server provides web-based user interface making possible several project members collaborate upload debugging symbols browse crash reports associate bugs crash reports abrt automated bug reporting tool claimed distro-independent deployed fedora red hat enterprise linux distributions abrt intercepts core dumps applications user-confirmation sends bug reports various bug-tracking systems fedora bugzilla ubuntu hosts public error tracker errors.ubuntu.com collects hundreds thousands error reports daily millions machines program crashes ubuntu crash handler apport notify user offer report crash user chooses report crash details possibly including core dump uploaded ubuntu server daisy.ubuntu.com analysis core dump automatically processed create stack trace crash signature crash signature used classify subsequent crash reports caused error bug buddy crash reporting tool used gnome platform application using gnome libraries crashes bug buddy generates stack trace using gdb invites user submit report gnome bugzilla user add comments view details crash report crash reporting tool used kde called dr. konqi user also get backtrace using gdb talkback also known quality feedback agent crash reporter used mozilla software version 1.8.1 report crashes products centralized server aggregation case-by-case analysis talkback proprietary software licensed mozilla corporation supportsoft mozilla product e.g mozilla firefox mozilla thunderbird crash talkback enabled talkback agent would appear prompting user provide optional information regarding crash talkback replace native os crash reporter enabled appear along talkback agent talkback replaced breakpad firefox since version 3 breakpad previously called airbag open-source replacement talkback developed google mozilla used current mozilla products firefox thunderbird significance first open source multi-platform crash reporting system since 2007 breakpad included firefox windows mac os x linux breakpad typically paired socorro receives classifies crashes users breakpad part crash reporting system includes reporting mechanism crashpad open-source crash reporter used google chromium developed replacement breakpad due update macos 10.10 removed api used breakpad crashpad currently consists crash-reporting client related tools macos windows considered substantially complete platforms crashpad became crash reporter client chromium macos march 2015 windows november 2015 world warcraft another program use crash reporter error reporter error reporter may detect crashes time sometimes os crash reporter invoked instead error reporter even known crash reporting errors android ios operating systems also built crash reporting functionality
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Operating systems
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udp flood attack udp flood attack denial-of-service dos attack using user datagram protocol udp sessionless/connectionless computer networking protocol using udp denial-of-service attacks straightforward transmission control protocol tcp however udp flood attack initiated sending large number udp packets random ports remote host result distant host thus large number udp packets victimized system forced sending many icmp packets eventually leading unreachable clients attacker may also spoof ip address udp packets ensuring excessive icmp return packets reach anonymizing network location operating systems mitigate part attack limiting rate icmp responses sent udp flood attack tools attack managed deploying firewalls key points network filter unwanted network traffic potential victim never receives never responds malicious udp packets firewall stops however firewalls 'stateful i.e hold number sessions firewalls also susceptible flood attacks
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Computer security
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cheetah mobile cheetah mobile inc chinese mobile internet company headquartered beijing china creator popular global mobile apps 634 million monthly active users jan 2017 company established 2010 merger kingsoft security conew image grew second-largest internet security software provider china according iresearch company located 1st yaojiayuan south rd chaoyang district beijing china 2014 cheetah mobile launched ipo selling 12 million american depositary shares us 14 per share thereby raised us 168 million ipo managed morgan stanley jp morgan chase co. credit suisse group kingsoft tencent major investors cheetah mobile holding 54 18 respectively late 2015 cheetah mobile announced entered global strategic partnership yahoo company incorporated yahoo ’ search native advertising platforms within apps result cheetah mobile stated revenue generated yahoo increased 30 percent daily within first two weeks february 2016 cheetah mobile cubot launched cheetahphone android 6.0 marshmallow based smartphone mwc barcelona spain august 2 2016 cheetah mobile announced acquisition french startup news republic 57 million news republic news aggregator cheetah mobile ad supported products include despite popularity clean master android app reported 2014 ads promoting clean master manipulate android users deceptive tactics browsing websites within app advertising framework april 2014 ferenc lászló nagy sophos labs captured pop-up ads led clean master warning device infected virus july 2014 cheetah mobile encouraged users uninstall google chrome replace cheetah mobile browser clean master clean optimization process practice allowed cheetah mobile gain unfair position marketplace led google crackdown december 2018 cheetah mobile implicated massive click fraud scheme leading google remove two apps play store cheetah mobile denied charges
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Computer security
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sun-3 sun-3 series unix computer workstations servers produced sun microsystems launched september 9 1985 sun-3 series vmebus-based systems similar earlier sun-2 series using motorola 68020 microprocessor combination motorola 68881 floating-point co-processor optional sun 3/50 proprietary sun mmu sun-3 systems supported sunos versions 3.0 4.1.1_u1 also current support netbsd linux models listed approximately chronological order max ram sizes may greater third-party memory board used 1989 coincident launch sparcstation 1 sun launched three new sun-3 models 3/80 3/470 3/480 unlike previous sun-3s use motorola 68030 processor 68882 floating-point unit 68030 integral mmu 68030-based architecture called sun-3x sun 3/260s upgraded sun 3400 cpu boards known sun 3/460s
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Computer architecture
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lga 775 lga 775 also known socket intel desktop cpu socket lga stands land grid array unlike earlier common cpu sockets predecessor socket 478 lga 775 socket holes instead 775 protruding pins touch contact points underside processor cpu socket unusually long life span lasting 7 years last processors supporting ceased production 2011 socket superseded lga 1156 socket h lga 1366 socket b sockets lga 775 distance four screw holes heatsink 72 mm thus interchangeable ones sockets lga 1156 1155 1150 1151 distance 75 mm prescott cedar mill pentium 4 cores well smithfield presler pentium cores used lga 775 socket july 2006 intel released desktop processor core 2 duo codenamed conroe also uses socket subsequent core 2 quad intel changed socket 478 lga 775 new pin type offers better power distribution processor allowing front-side bus raised 1600 mt/s 't socket derived cancelled tejas core replace prescott core another advantage intel newer architecture motherboard pins rather cpu transferring risk pins bent cpu motherboard cpu pressed place load plate rather human fingers directly installer lifts hinged load plate inserts processor closes load plate top processor pushes locking lever pressure locking lever load plate clamps processor 775 copper contact points firmly onto socket 775 pins ensuring good connection load plate covers edges top surface cpu integrated heat spreader center free make contact cooling device placed top cpu spacing cpu cooler mounting holes 72mm x 72mm examination relevant intel data sheets shows lga 775 used consumer level desktops lga 771 used xeon based intel workstation server class computers appear differ placement indexing notches swap two address pins many pins devoted functions interfacing multiple cpus clearly defined lga 775 specifications information available appear consistent lga 771 considering lga 775 predated lga 771 nearly year half would seem lga 771 adapted lga 775 rather way around fact using adapter allow lga 771 processors used lga 775 motherboards i845gv/ge/i848p/i865g/gv/p/pe/i910gl/i915g/gl/gv/p/pl/i925x/xe/ lakeport 945pl /945p 945g 945gc 945gz 955x 946pl 946gz p broadwater i955x i946 946gz pl 965 i975 q965 p965 g965 q963 i975x bearlake x35 p35 q35 g35 p33 g33 q33 p31 g31 x38 eaglelake x48 p45 p43 g45 g43 g41 b43 q43 q45 sis 649/649fx/655/656/656fx/662/671/671fx/671dx/672 pt800/pm800/pt880/pm880/p4m800/p4m800 pro/pt880 pro/pt880 ultra/pt894/pt894 pro/p4m890/pt890/p4m900 ati radeon xpress 200 ati radeon xpress 1250 ati crossfire xpress 3200 nforce4 ultra nforce4 sli xe nforce4 sli nforce4 sli x16 nforce 570 sli nforce 590 sli nforce 610i nforce 630i nforce 650i ultra nforce 650i sli nforce 680i lt sli nforce 680i sli nforce 730i nforce 740i sli nforce 750i sli nforce 760i sli nforce 780i sli nforce 790i sli geforce 9300 geforce 9400 sources force load plate ensures processor completely level giving cpu upper surface optimal contact heat sink cold-water block fixed onto top cpu carry away heat generated cpu socket also introduces new method connecting heat dissipation interface chip surface motherboard lga 775 heat dissipation interface connected directly motherboard four points compared two connections socket 370 clamshell four-point connection socket 478 done avoid reputed danger heat sinks/fans pre-built computers falling transit lga 775 announced better heat dissipation properties socket 478 designed replace prescott core cpus early incarnations ran much hotter previous northwood-core pentium 4 cpus initially neutralized benefits better heat transfer however modern core 2 processors run much lower temperatures prescott cpus replace lga 775 processors following mechanical maximum load limits exceeded heat sink assembly shipping conditions standard use load limits could crack processor die make unusable transition lga packaging lowered load limits smaller load limits socket 478 processors bigger socket 370 socket 423 socket processors fragile large enough ensure processors crack compatibility quite variable earlier chipsets intel 915 tend support single core netburst pentium 4 celeron cpus fsb 533/800 mt/s intermediate chipsets e.g intel 945 commonly support single core pentium 4-based cpus well dual core pentium processors 945 chipset-based motherboards could given bios upgrade support 65nm core-based cpus chipsets also varies lga 775 cpu support complicated mixture chipset capability voltage regulator limitations bios support example g41 chipset n't support netburst cpus pentium pentium extreme edition pentium 4 celeron
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Computer architecture
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features new windows 8 transition windows 7 windows 8 introduced number new features across various aspects operating system include greater focus optimizing operating system touchscreen-based devices tablets cloud computing windows 8 introduces new windows runtime winrt platform used create new type application officially known windows store apps commonly called metro-style apps apps run within secure sandbox share data apps common apis winrt com-based api allows use various programming languages code apps including c++ c++/cx c visual basic .net html5 javascript metro-style apps packaged distributed via appx new file format package management unlike desktop applications metro-style apps sideloaded subject licensing conditions windows 8.1 update allows sideloading apps windows 8.1 pro devices joined active directory domain windows 8 two apps may snap side widescreen display allow multi-tasking forming sidebar separates apps windows 8.1 apps continually resized desired width snapped apps may occupy half screen large screens allow four apps snapped upon launching app windows allows user pick snapped view app open term metro-style apps referred metro design language prominently used windows 8 recent microsoft products reports surfaced microsoft employees told stop using term due potential trademark issues unspecified partner microsoft spokesperson however denied reports stated metro-style merely codename new application platform windows 8 introduces apis support near field communication nfc windows 8 devices allowing functionality like launching urls/applications sharing information devices via nfc windows store digital distribution platform built windows 8 manner similar apple app store google play allows distribution purchase apps designed windows 8 developers still able advertise desktop software windows store well ensure secure high quality windows store means distributing winrt-based apps consumer-oriented versions windows 8 windows 8.1 windows store features redesigned interface improved app discovery recommendations offers automatic updates apps windows 8 features redesigned user interface built upon metro design language optimizations touchscreens metro-style apps either run full-screen environment snapped side screen alongside another app desktop snapping requires screen resolution 1366×768 higher windows 8.1 lowers snapping requirement screen resolution 1024x768 users switch apps desktop clicking top left corner swiping left side touchscreen invoke sidebar displays currently opened metro-style apps right-clicking upper left corner provides context menu options switch open apps traditional desktop accessible tile start screen launching desktop app shortcut cycles programs regardless type interface also incorporates taskbar right side screen known charms lowercase accessed app desktop sliding right edge touchscreen compatible trackpad moving mouse cursor one right corners screen pressing charms include search share start devices settings charms start charm invokes dismisses start screen charms invoke context-sensitive sidebars used access app system functionality aforementioned changes involving use hot corners user interface navigation windows 8 fundamentally different compared previous versions windows assist new users operating system microsoft incorporated tutorial appears installation windows 8 also first sign-in new user account visually instructs users move mouse cursor corner screen swipe corners devices touchscreens interact operating system tutorial disabled appear new user accounts windows 8.1 introduces navigation hints instructions displayed first use operating system also includes help support app windows 8.1 aforementioned hotspots upper right upper left corners disabled pressing right-clicking bottom left corner screen opens quick link menu menu contains shortcuts frequently used areas control panel file explorer programs features run search power options task manager windows 8.1 quick link menu includes options shut restart device windows 8.1 update introduced changes facilitate mouse-oriented means switching closing metro-style apps patterned upon mechanics used desktop programs windows user interlace lieu recent apps sidebar computer icons opened apps displayed taskbar desktop programs shortcuts apps also pinned taskbar mouse connected auto-hiding titlebar minimize close buttons displayed within apps mouse moved toward top screen number apps included standard installation windows 8 including mail email client people contact manager messaging im client calendar calendaring app photos image viewer music audio player video video player camera webcam digital camera client skydrive reader e-book reader six apps expose bing services search news finance weather travel sports windows 8.1 adds calculator alarm clock sound recorder reading list food drink health fitness help tips scan file manager integrated skydrive app windows 8 also includes metro-style system component called pc settings exposes small portion control panel settings windows 8.1 improves component include options previously exclusive control panel windows 8.1 update adds additional options pc settings windows 8 introduces new form start menu called start screen resembles home screen windows phone shown place desktop startup start screen serves primary method launching applications consists grid app tiles arranged columnar groups groups arranged without group names app tiles either small taking 1 square large taking 2 squares size also display dynamic content provided corresponding apps notifications slide shows users arrange individual app tiles entire groups additional section start screen called apps accessed via right click mouse upward swipe display installed apps categorized names semantic zoom feature available start screen apps view enables users target specific area group screen start screen uninstall apps directly windows 8.1 makes following changes start screen windows 8.1 reverts two changes featured windows 8 windows 8 removed start button taskbar favor ways invoking start screen windows 8.1 restores button windows 8 also showed start screen upon logon opposed editions windows show desktop windows 8.1 user may choose one see first windows 8.1 update boots desktop default non-tablet devices introduces ability switch taskbar start screen open metro-style app directing mouse cursor toward bottom screen windows 8.1 introduces new slide shutdown option allows users drag partially revealed lock screen image toward bottom screen shut operating system windows 8.1 update introduces visible power button start screen power button appear hardware device types default new account profiles windows 8.1 update also receive four additional tiles pinned start screen pc pc settings documents pictures windows rt pc settings tile added windows 8 searching start screen clicking search charm display search results within full-screen interface unlike previous versions windows searching start menu returned results multiple sources simultaneously windows 8 searches individual categories apps settings files default windows 8 searches apps user begins searching start screen search charm also search categories user interface via keyboard shortcuts pressing opens search charm search apps searches files searches settings search queries also redirected specific categories apps entered searching apps windows 8 display list apps support search charm frequently used apps prioritized users pin individual apps always appear search charm also search directly within apps user redirects entered search query specific app presses within app already open searching files windows 8 highlight words phrases match search query provide suggestions based content properties files appear information files associated programs sizes appear directly beneath filenames user hovers file mouse cursor long presses finger tooltip appear display additional information windows 8.1 searching longer opens full-screen interface results instead displayed metro-style flyout interface windows 8.1 also reinstates unified local search results optionally provide results bing dubbed smart search windows 8.1 bing optionally analyze user search habits return relevant content stored locally internet enabled smart search exposes additional search categories within user interface web images web videos accessed via new keyboard shortcut new full screen hero interface powered bing display aggregated multimedia photos youtube videos songs/albums xbox music content news articles wikipedia entries related search query like predecessor windows 8.1 allows users search setting file categories option search category apps removed interface keyboard shortcut previously associated functionality displays unified search results search charm also longer search within apps directly display list compatible apps search content within apps users must first open app available use search feature within app interface windows 8.1 update enhances bing smart search feature providing support natural language queries detect misspellings display apps settings relevant query example typing get apps windows display shortcut windows store windows 8.1 update also introduces visible search button start screen acts shortcut metro-style flyout interface windows 8 introduces redesigned lock screen interface based metro design language lock screen displays customizable background image current date time notifications apps detailed app status updates two new login methods optimized touch screens also available including four-digit pin picture password users allow use certain gestures performed selected picture log gestures take account shape start end points well direction however shapes gestures limited tapping tracing line circle microsoft found limiting gestures increased speed sign-ins three times compared allowing freeform methods wrong gestures always deny login lock pc five unsuccessful attempts text password provided windows 8.1 introduces ability display photo slide show lock screen feature display images local remote directories includes additional options use photos optimized current screen resolution disable slide show device running battery power display lock screen slide show instead turning screen period user inactivity lock screen also display interactive toast notifications examples users answer calls instant messages received skype contacts dismiss alarm notifications lock screen users also take photos without dismissing lock screen windows 8 introduces new forms notifications metro-style apps certain events file explorer pc settings component includes options globally disable toast notifications app notifications lock screen notification sounds notifications also disabled per-app basis settings charm windows 8 provides additional options suppress toast notifications 1 hour 3 hour 8 hour time intervals windows 8.1 introduces quiet hours feature also available windows phone allows users suppress notifications based time day e.g. notifications disabled 12:00 6:00 pm windows 8 allows users link profiles microsoft account provide additional functionality synchronization user data settings including belonging desktop allows integration microsoft services xbox live xbox music xbox video gaming multimedia skydrive online file storage windows 8 includes improved support multi-monitor configurations taskbar optionally shown multiple displays display also show dedicated taskbar addition options available prevent taskbar buttons appearing certain monitors wallpapers also spanned across multiple displays display separate wallpaper windows 8.1 includes improved support high-resolution monitors desktop scaling feature helps resize items desktop solve visibility problems screens high native resolution windows 8.1 also introduces per-display dpi scaling provides option scale 200 windows explorer renamed file explorer incorporates ribbon toolbar designed bring forward commonly used commands easy access button advances user back level folder hierarchy removed explorer windows xp also restored additionally file explorer features redesigned preview pane takes advantage widescreen layouts file explorer also provides built-in function mounting iso img vhd files virtual drives easier management files folders windows 8 introduces ability move selected files folders via drag drop parent folder subfolder listed within breadcrumb hierarchy address bar file explorer progress windows file operations also redesigned offering ability show multiple operations graph tracking transfer speeds ability pause resume file transfer new interface also introduced managing file name collisions file operation allowing users easily control conflicting files copied libraries introduced windows 7 individual icons changed user interface previously users change icons manually editing configuration files windows 8.1 however longer creates default libraries new users display libraries listing file explorer default instead windows 8.1 introduces shortcuts default user profile folders documents downloads pictures etc within pc location file explorer windows 8 ships internet explorer 10 run either desktop program operates similarly internet explorer 9 app new full-screen interface optimized use touchscreens internet explorer 10 also contains integrated version flash player available full desktop limited form within metro app windows 8.1 ships internet explorer 11 includes tab syncing webgl spdy support along expanded developer tools metro version also adds access favorites split-screen snapping multiple tabs additional option always display address bar tabs also available metro version also detect highlight phone numbers web page turn clickable links clicked initiate call compatible app skype windows 8 includes overhauled version task manager features following changes windows 8 introduces revised virtual also known on-screen keyboard interface optimized touchscreen devices includes wider spacing keys designed prevent common typing errors occur using touchscreens pressing holding key reveals related keys accessed via press swipe suggestions incomplete words available emoji characters also supported windows 8.1 introduces ability swipe space bar desired direction suggested word switch on-screen suggestions windows 8.1 update introduces new gesture allows users tap twice hold second tap drag drop highlighted text objects visible option hide show virtual keyboard also available windows 8 displays peek button password text boxes optionally allows users view passwords entered order ensure typed correctly feature disabled via group policy file history continuous data protection component file history automatically creates incremental backups files stored libraries including users participating homegroup user-specified folders different storage device another internal external hard drive storage space network share specific revisions files tracked restored using history functions file explorer file history replaces backup restore shadow copy known windows explorer previous versions main backup tool windows 8 unlike shadow copy performs block-level tracking files file history utilizes usn journal track changes simply copies revisions files backup location unlike backup restore file history back files encrypted efs windows 8 adds native support usb 3.0 allows faster data transfers improved power management compatible devices native stack includes support newer efficient usb attached scsi uas protocol turned default even usb 2.0 devices although must however supporting firmware/hardware take advantage windows 8.1 enhanced support power saving features usb storage devices addition without problems poorly implemented hardware degrading user experience hangs disconnects support advanced format hard drives without emulation included first time port windows arm architecture also created windows 8 known windows rt specifically optimized mobile devices tablets windows rt able run third-party windows store apps comes preinstalled version office 2013 specially redesigned touchscreen use windows 8.1 improves hardware support directx 11.2 alongside existing winpe-based windows setup used installations initiated booting dvd usb network upgrade assistant offered provide simpler faster process upgrading windows 8 previous versions windows program runs compatibility check scan device hardware software windows 8 compatibility allows user purchase download generate installation media dvd usb flash drive install windows 8 new installation process also allows users transfer user data clean installation windows similar program branded windows 8 setup used installations user already product key windows 8 implements oem activation 3.0 allows microsoft digitally distribute windows licenses original equipment manufacturers oems windows 8 devices store product keys directly firmware rather printed certificate authenticity coa sticker new system designed prevent oem product keys used computers licensed also allows installer automatically detect accept product key event re-installation windows 8.1 update adds new installation mode known wimboot wim image contains windows installation left compressed rather extracted system configured use files directly within system image installation method primarily designed reduce footprint windows installation devices small amounts storage system image also doubles recovery image speeding refresh reset operations supported systems unified extensible firmware interface uefi windows located solid-state drive emmc windows 8 incorporates improved support mobile broadband first-class method internet connectivity upon insertion sim card operating system automatically determine user carrier configure relevant connection settings using access point name database operating system also monitor mobile data usage changes behavior accordingly reduce bandwidth use metered networks carriers also offer dedicated windows store apps account management also installed automatically part connection process functionality demonstrated app could also display monthly data usage statistics live tile windows 8 also reduces need third-party drivers software implement mobile broadband providing generic driver providing integrated airplane mode option windows 8 supports geolocation windows 8.1 adds support nfc printing mobile broadband tethering auto-triggered vpn geofencing windows 8.1 update provides options network settings charm show estimated data usage selected network designate network metered connection windows 8 defaults hybrid boot mode operating system shut hibernates kernel allowing faster boot subsequent startup improvements compounded using processor cores startup default create seamless transition power-on self-test windows startup process manufacturers logos shown windows boot screen compatible systems uefi advanced startup menu uses graphical interface mouse touch support place text-based menu used previous versions increased boot speed devices uefi make difficult access using keyboard shortcuts boot menu launched within windows—using either pc settings app holding shift clicking restart option power menu using new -o switch shutdown.exe though legacy version advanced startup menu still enabled instead uefi firmware exposed windows via class drivers updated firmware capsules distributed update driver signed package inf file security catalog similarly devices driver installed windows prepares update installed next boot windows boot manager renders status information device boot screen windows 8 includes wddm 1.2 directx graphics infrastructure dxgi 1.2 desktop window manager runs times even systems unsupported graphics cards dwm also supports software rendering also includes support stereoscopic 3d content major features include preemptive multitasking finer granularity dma buffer primitive triangle pixel instruction-level reduced memory footprint improved resource sharing improved timeout detection recovery 16-bit color surface formats 565 5551 4444 mandatory windows 8 direct3d 11 video supports yuv 4:4:4/4:2:2/4:2:0/4:1:1 video formats 8 10 16-bit precision well 4 8-bit palettized formats windows 8.1 introduces wddm 1.3 adds support miracast enables wireless wired delivery compressed standard- high-definition video desktops tablets mobile phones devices windows 8 adds support printer driver architecture version 4 adds metro friendly interface well changes way architecture written windows 8.1 adds support wi-fi direct printing nfc printing native apis 3d printing xml-based 3d manufacturing format 3mf windows powershell microsoft task automation framework consisting command-line shell associated scripting language built .net framework powershell provides full access com wmi enabling administrators perform administrative tasks local remote windows systems windows 8 includes windows powershell v3.0 windows 8.1 comes windows powershell v4.0 features host new commands managing start screen windows defender windows components hardware network windows go feature exclusive enterprise version windows 8 allows organization provision bootable usb flash drives windows installation allowing users access managed environment compatible pc windows 8.1 updates feature enable booting usb composite device storage smart card function action center introduced windows 7 expanded include controls notifications new categories smartscreen status drive health status file history device software updates new automatic maintenance feature periodically perform number maintenance tasks diagnostics updates malware scans improve system performance pc settings app windows 8 used interact windows update although traditional interface control panel retained windows 8 able distribute firmware updates compatible devices configured automatically download windows updates metered networks new set windows powershell cmdlets enable adding removing features windows programs features applet control panel deployment image servicing management dism utility windows 8 includes features previously available imagex able periodically check component store corruption repair report amount disk space use winsxs folder also determine cleanup performed windows 8 detect system experiencing issues preventing system functioning correctly automatically launch advanced startup menu access diagnostic repair functions system recovery windows 8 introduced new functions known collectively push-button reset allows user re-install windows without needing use installation media feature consists reset refresh functions accessible within advanced boot options menu pc settings options reboot system windows recovery environment perform requested operation refresh preserves user profiles settings windows store apps reset performs clean installation windows reset function may also perform specialized disk wiping formatting procedures added security operations remove installed desktop applications system users also create custom disk image use refresh reset windows 8 introduces virtual smart card support digital certificate smart card stored onto user machine protected trusted platform module thereby eliminating need user physically insert smart card though entering pin still required virtual smart card support enables new two-factor authentication scenarios windows 8.1 improves functionality simplifying device enrollment process virtual smart cards introduces additional virtual smart card functionality metro-style applications enrollment management features via winrt apis windows 8.1 features pervasive support biometric authentication throughout operating system includes native fingerprint registration feature enables use fingerprint tasks signing device purchasing apps windows store consenting authentication prompts e.g. user account control windows 8.1 also introduces new winrt apis biometrics windows rt logging microsoft account automatically activates passive device encryption feature-limited version bitlocker seamlessly encrypts contents mobile devices protect contents windows 8.1 device encryption similarly available x86-based windows devices automatically encrypting user data soon operating system configured user signs microsoft account supported active directory network recovery key generated saved directly user account unlike bitlocker device encryption x86-based devices requires device meet connected standby specifications among requirements requires device use solid state storage ram soldered directly motherboard trusted platform module tpm 2.0 chip windows 8.1 introduces assigned access formerly called kiosk mode restricts windows device running single predetermined metro-style app windows 8.1 slated include provable pc health feature would allow owners subject devices connected network remote pc analysis provable pc health connected devices would periodically send various configuration-related information cloud service would provide suggestions remediation upon detection issue however feature dropped operating system general availability windows 8 integrates windows live family safety operating system allowing parents restrict user activity via web filtering application restriction computer usage time limits parental controls functionality introduced windows vista previously partially removed windows 7 made part windows live family safety instead notable change family safety administrators specify time periods computer usage example administrator restrict user account remained signed total time period one hour previous versions windows administrators could restrict accounts based time day windows 8 introduced four new features offer security startup process uefi secure boot trusted boot measured boot early launch anti-malware elam four secure boot native feature windows 8 part uefi startup uefi firmware checks validity digital signature present windows boot loader bootmgfw.efi signed microsoft public key signature check happens every time computer booted prevents malware infecting system operating system loads uefi firmware allow signatures keys enrolled database prior windows 8 release microsoft announced certified computers ship microsoft public key enrolled secure boot enabled default however following announcement company accused critics free open-source software advocates including free software foundation trying use secure boot hinder outright prevent installation alternative operating systems linux microsoft denied secure boot requirement intended serve form lock-in clarified x86 certified systems arm systems must allow secure boot enter custom mode disabled trusted boot feature windows boot loader ensures integrity microsoft components loaded memory including elam loads last elam ensures third-party boot drivers trustworthy loaded elam check fails elam use either windows defender third-party compatible antivirus 2011 build conference anaheim california microsoft showed windows 8 machine prevent infected usb flash memory compromising boot process measured boot attest state client machine sending details configuration remote machine feature relies attestation feature trusted platform module designed verify boot integrity client windows platform binary table allows executable files stored within uefi firmware execution startup microsoft states feature meant allow critical software persist even operating system changed reinstalled 'clean configuration specifically anti-theft security software also mis-used including lenovo lenovo service engine feature windows 8 includes updated windows defender antivirus program defends system broad range malware including computer viruses computer worms spyware windows 8.1 augments network inspection system nis network intrusion detection system feature present microsoft security essentials since july 2010 windows 8 includes various features controlled keyboard shortcuts hyper-v native hypervisor previously offered windows server included windows 8 pro replacing windows virtual pc hosted hypervisor storage spaces storage virtualization technology succeeds logical disk manager allows organization physical disks logical volumes similar logical volume manager linux raid1 raid5 higher abstraction level storage space behaves like physical disk user thin provisioning available disk space spaces organized within storage pool i.e collection physical disks span multiple disks different sizes performance technology usb sata sas process adding new disks replacing failed older disks fully automatic controlled powershell commands storage pool host multiple storage spaces storage spaces built-in resiliency disk failures achieved either disk mirroring striping parity across physical disks storage pool refs filesystem limited 4 pb 4096 tb limits total number storage pools number storage spaces within pool review ars technica concluded storage spaces windows 8 good foundation current iteration simply flawed recommend circumstances microsoft mvp helge klein also criticized storage spaces unsuitable touted market soho users storage spaces enhanced windows server 2012 r2 tiering caching support used caching ssd new features added windows 8.1 instead windows 8.1 gained support specific features sshd drives e.g host-hinted lba caching tp_042v14_sata31_hybrid information windows 8.1 also gained support nvm express nvme new industry standard protocol pcie-attached storage pcie flash cards
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Operating systems
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national cyber security hall fame national cyber security hall fame founded larry letow rick geritz established 2012 recognize contributions key individuals field cyber security mission statement respect past protect future according website designed honor innovative individuals organizations vision leadership create fundamental building blocks cyber security industry organization also highlights major milestones industry 40-year history timeline representation includes inductees corresponding accomplishments nominations cyber security hall fame submitted following categories reviewed advisory committee chaired 2013 mike jacobs 2019 members cyber security hall fame advisory board
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Computer security
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pulse-code modulation pulse-code modulation pcm method used digitally represent sampled analog signals standard form digital audio computers compact discs digital telephony digital audio applications pcm stream amplitude analog signal sampled regularly uniform intervals sample quantized nearest value within range digital steps linear pulse-code modulation lpcm specific type pcm quantization levels linearly uniform contrast pcm encodings quantization levels vary function amplitude a-law algorithm μ-law algorithm though pcm general term often used describe data encoded lpcm pcm stream two basic properties determine stream fidelity original analog signal sampling rate number times per second samples taken bit depth determines number possible digital values used represent sample early electrical communications started sample signals order multiplex samples multiple telegraphy sources convey single telegraph cable american inventor moses g. farmer conveyed telegraph time-division multiplexing tdm early 1853 electrical engineer w. m. miner 1903 used electro-mechanical commutator time-division multiplexing multiple telegraph signals also applied technology telephony obtained intelligible speech channels sampled rate 3500–4300 hz lower rates proved unsatisfactory 1920 bartlane cable picture transmission system used telegraph signaling characters punched paper tape send samples images quantized 5 levels 1926 paul m. rainey western electric patented facsimile machine transmitted signal using 5-bit pcm encoded opto-mechanical analog-to-digital converter machine go production british engineer alec reeves unaware previous work conceived use pcm voice communication 1937 working international telephone telegraph france described theory advantages practical application resulted reeves filed french patent 1938 us patent granted 1943 time reeves started working telecommunications research establishment first transmission speech digital techniques sigsaly encryption equipment conveyed high-level allied communications world war ii 1943 bell labs researchers designed sigsaly system became aware use pcm binary coding already proposed reeves 1949 canadian navy datar system ferranti canada built working pcm radio system able transmit digitized radar data long distances pcm late 1940s early 1950s used cathode-ray plate electrode encoding perforations oscilloscope beam swept horizontally sample rate vertical deflection controlled input analog signal causing beam pass higher lower portions perforated plate plate collected passed beam producing current variations binary code one bit time rather natural binary grid goodall later tube perforated produce glitch-free gray code produced bits simultaneously using fan beam instead scanning beam united states national inventors hall fame honored bernard m. oliver claude shannon inventors pcm described communication system employing pulse code modulation filed 1946 1952 granted 1956 another patent title filed john r. pierce 1945 issued 1948 three published philosophy pcm 1948 t-carrier system introduced 1961 uses two twisted-pair transmission lines carry 24 pcm telephone calls sampled 8 khz 8-bit resolution development improved capacity call quality compared previous frequency-division multiplexing schemes 1967 first pcm recorder developed nhk research facilities japan 30 khz 12-bit device used compander similar dbx noise reduction extend dynamic range stored signals video tape recorder 1969 nhk expanded system capabilities 2-channel stereo 32 khz 13-bit resolution january 1971 using nhk pcm recording system engineers denon recorded first commercial digital recordings 1972 denon unveiled first 8-channel digital recorder dn-023r used 4-head open reel broadcast video tape recorder record 47.25 khz 13-bit pcm audio 1977 denon developed portable pcm recording system dn-034r like dn-023r recorded 8 channels 47.25 khz used 14-bits emphasis making equivalent 15.5 bits 1973 adaptive differential pulse-code modulation adpcm developed p. cummiskey nikil jayant james l. flanagan compact disc cd brought pcm consumer audio applications introduction 1982 cd uses 44,100 hz sampling frequency 16-bit resolution stores 80 minutes stereo audio per disc pcm method encoding typically used uncompressed digital audio diagram sine wave red curve sampled quantized pcm sine wave sampled regular intervals shown vertical lines sample one available values y-axis chosen pcm process commonly implemented single integrated circuit called analog-to-digital converter adc produces fully discrete representation input signal blue points easily encoded digital data storage manipulation several pcm streams could also multiplexed larger aggregate data stream generally transmission multiple streams single physical link one technique called time-division multiplexing tdm widely used notably modern public telephone system electronics involved producing accurate analog signal discrete data similar used generating digital signal devices digital-to-analog converters dacs produce voltage current depending type represents value presented digital inputs output would generally filtered amplified use recover original signal sampled data demodulator apply procedure modulation reverse sampling period demodulator reads next value transitions output signal new value result transitions signal gains significant amount high-frequency energy due aliasing effects remove undesirable frequencies demodulator passes signal reconstruction filter suppress energy outside expected frequency range greater nyquist frequency formula_1 common sample depths lpcm 8 16 20 24 bits per sample lpcm encodes single sound channel support multichannel audio depends file format relies synchronization multiple lpcm streams two channels stereo common format systems support 8 audio channels 7.1 surround common sampling frequencies 48 khz used dvd format videos 44.1 khz used compact discs sampling frequencies 96 khz 192 khz used equipment benefits debated nyquist–shannon sampling theorem shows pcm devices operate without introducing distortions within designed frequency bands provide sampling frequency least twice highest frequency contained input signal example telephony usable voice frequency band ranges approximately 300 hz 3400 hz effective reconstruction voice signal telephony applications therefore typically uses 8000 hz sampling frequency twice highest usable voice frequency regardless potential sources impairment implicit pcm system forms pcm combine signal processing coding older versions systems applied processing analog domain part analog-to-digital process newer implementations digital domain simple techniques largely rendered obsolete modern transform-based audio compression techniques telephony standard audio signal single phone call encoded 8,000 samples per second 8 bits giving 64 kbit/s digital signal known ds0 default signal compression encoding ds0 either μ-law mu-law pcm north america japan a-law pcm europe rest world logarithmic compression systems 12- 13-bit linear pcm sample number mapped 8-bit value system described international standard g.711 circuit costs high loss voice quality acceptable sometimes makes sense compress voice signal even adpcm algorithm used map series 8-bit µ-law a-law pcm samples series 4-bit adpcm samples way capacity line doubled technique detailed g.726 standard later found even compression possible additional standards published international standards describe systems ideas covered privately owned patents thus use standards requires payments patent holders adpcm techniques used voice ip communications pcm either return-to-zero rz non-return-to-zero nrz nrz system synchronized using in-band information must long sequences identical symbols ones zeroes binary pcm systems density 1-symbols called ones-density ones-density often controlled using precoding techniques run length limited encoding pcm code expanded slightly longer code guaranteed bound ones-density modulation channel cases extra framing bits added stream guarantee least occasional symbol transitions another technique used control ones-density use scrambler polynomial raw data tend turn raw data stream stream looks pseudo-random raw stream recovered exactly reversing effect polynomial case long runs zeroes ones still possible output considered unlikely enough within normal engineering tolerance cases long term dc value modulated signal important building dc offset tend bias detector circuits operating range case special measures taken keep count cumulative dc offset modify codes necessary make dc offset always tend back zero many codes bipolar codes pulses positive negative absent typical alternate mark inversion code non-zero pulses alternate positive negative rules may violated generate special symbols used framing special purposes word pulse term pulse-code modulation refers pulses found transmission line perhaps natural consequence technique evolved alongside two analog methods pulse width modulation pulse position modulation information encoded represented discrete signal pulses varying width position respectively respect pcm bears little resemblance forms signal encoding except used time division multiplexing numbers pcm codes represented electrical pulses device performs coding decoding function telephone circuit called codec
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Internet protocols
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eten chinese system eten chinese system 倚天中文系統 popular dos-compatible traditional chinese operating system chinese windows 95 dos support chinese characters extended ascii many companies taiwan developed ibm pc compatible traditional chinese operating system running dos mutually incompatible os kuo chia 國喬 acer developer eten os e-ten earned early profits sales hardware based plug-in card based chinese system products software chinese systems widely copied many traditional chinese users software pirates difficult e-ten control traditional chinese products compatible eten os time microsoft developed chinese windows 3.1 windows 95 traditional chinese software developer users shifted windows dos last version eten os chinese windows-compatible version eten traditional chinese os used dos based pos systems
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Computer architecture
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socket 423 socket 423 423 pin cpu socket used first generation pentium 4 processors based willamette core replaced socket 478 2001 socket houses processor designed socket 423 package socket short-lived became apparent electrical design proved inadequate raising clock speed beyond 2.0 ghz intel produced chips using socket less year november 2000 august 2001 replaced socket 478 processors used socket also locked multiplier means overclockable unless front side bus frequency increased however raising fsb frequency could push buses spec thus cause system instability powerleap pl-p4/n device developed form socket adapter allowing use socket 478 processors socket 423
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Computer architecture
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turing microarchitecture turing codename graphics processing unit gpu microarchitecture developed nvidia successor volta architecture named prominent mathematician computer scientist alan turing architecture first introduced august 2018 siggraph 2018 along professional workstation quadro rtx products based one week later gamescom along consumer geforce rtx 20 series products based architecture introduces first consumer products capable real-time ray tracing longstanding goal computer graphics industry key elements include dedicated artificial intelligence processors tensor cores dedicated ray tracing processors turing leverages microsoft dxr optix vulkan access ray-tracing february 2019 nvidia released geforce 16 series gpus utilizes new turing design lacks ray tracing artificial intelligence cores turing manufactured using tsmc 12 nm finfet semiconductor fabrication process high-end tu102 gpu includes 18.6billion transistors fabricated using process turing also uses gddr6 memory samsung electronics previously micron technology turing microarchitecture combines multiple types specialized processor core enables implementation limited real-time ray tracing accelerated use new rt ray-tracing cores designed process quadtrees spherical hierarchies speed collision tests individual triangles features turing gddr6 memory produced samsung electronics quadro rtx series rtx 20 series initially launched micron memory chips switching samsung chips november 2018 nvidia reported rasterization cuda performance gains existing titles approximately 30–50 previous generation ray-tracing performed rt cores used produce reflections refractions shadows replacing traditional raster techniques cube maps depth maps instead replacing rasterization entirely however information gathered ray-tracing used augment shading information much photo-realistic especially regards off-camera action nvidia said ray-tracing performance increased 8 times previous consumer architecture pascal generation final image accelerated tensor cores used fill blanks partially rendered image technique known de-noising tensor cores perform result deep learning supercomputers codify example increase resolution images tensor cores primary usage problem solved analyzed supercomputer taught example results desired supercomputer determines method use achieve results done consumer tensor cores methods delivered via driver updates consumers turing development platform called rtx rtx uses microsoft dxr optix vulkan access ray-tracing includes access ai-accelerated features ngx windows 10 october 2018 update includes public release directx raytracing
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Computer architecture
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aquosa aquosa adaptive quality service architecture open architecture provisioning adaptive quality service functionality linux kernel project features flexible portable lightweight open architecture supporting qos related services top general-purpose operating system linux architecture well founded formal scheduling analysis control theoretical results key feature aquosa resource reservation layer capable dynamically adapting cpu allocation qos aware applications based run-time requirements order provide functionality aquosa embeds kernel-level cpu scheduler implementing resource reservation mechanism cpu based earliest deadline first edf gives ability linux kernel realize partially temporal isolation among tasks running within system aquosa one projects provides real-time scheduling capabilities unprivileged users multi-user system controlled way means properly designed access-control model architecture project may summarized follows lowest level patch linux kernel adds ability notify dynamically loaded modules relevant scheduling event identified creation death tasks well block unblock events patch minimally invasive consists lines code properly inserted mainly within linux scheduler code sched.c called generic scheduler patch potentially allows implement scheduling policy resource reservations layer composed three components core component dynamically loadable kernel module implements resource reservations scheduling paradigm cpu exploiting functionality introduced linux kernel generic scheduler patch second user-level library qres library allows application use new scheduling policy complete well-designed set api calls essentially calls allow application ask system reserve certain percentage cpu process es third kernel-level component supervisor mediates requests made applications qres library total sum requested cpu shares violate schedulability condition scheduler less one slightly less one due overhead supervisor behaviour completely configurable system administrator possible specify per-user/per-group basis minimum guaranteed maximum allowed values reservations made cpu aquosa applications may use directly resource reservation layer allows reserve fraction cpu run required scheduling guarantees example multimedia application may ask operating system run application guarantee scheduled least q milliseconds every p milliseconds q p depend nature application registering application resource reservation layer possible specify minimum guaranteed reservation system always guarantee application based requests minimum guaranteed reservations layer performs admission control i.e allows new application addition new set running applications overcome cpu saturation limit typical multimedia application making use high compression technologies may quite difficult impractical inconvenient run applications fixed reservation cpu fact efficient reservation used may vary time due varying compression level results varying decompression time traditional real-time systems make use wcet worst case execution time analysis techniques order compute maximum time instance example periodic task may execute cpu blocking waiting next instance analysis difficult today complex multimedia applications especially running general-purpose hardware like standard pcs technologies like multi-level caches cpu execution pipelines on-bus buffers multi-master buses introduce many unpredictable variables determining time required memory accesses systems much convenient tune system design based average expected load application otherwise system may significantly under-utilized runtime already mentioned certain classes multimedia applications video player quite impossible find appropriate fixed value fraction cpu required application run-time due heavy fluctuations load depending actual data processed application fixed reservation based average requirements slightly greater results transient periods poor quality runtime e.g movie playback hand fixed reservation based maximum expected load results unneeded over-reservation cpu time except periods load really approaches maximum expected value classes applications much convenient use adaptive reservation techniques like ones provided adaptive reservation layer aquosa performs continuous on-line monitoring computational requirements application process es may dynamically adapt reservation made cpu depending monitored data adaptive reservation layer exposes applications api using set controllers quite general use within wide set multimedia applications real-time variations linux require users real-time capabilities modified os root privileges system perfectly acceptable embedded system context however excessive multi-user systems real-time scheduling features needed multimedia applications similar therefore aquosa embeds dedicated access-control model system administrators details found paper topic published rtas 2008
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Operating systems
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nano-itx nano-itx computer motherboard form factor first proposed via technologies cebit march 2003 implemented late 2005 nano-itx boards measure fully integrated low power consumption motherboards many uses targeted smart digital entertainment devices pvrs set-top boxes media centers car pcs thin devices four nano-itx motherboard product lines far via epia n epia nl epia nx via epia nr boards available wide variety manufacturers supporting numerous different cpu platforms udoo released least 1 nano-itx board udoo bolt
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Computer architecture
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institute social inventions institute social inventions think-tank set 1985 publicise launch good ideas improving quality life founder nicholas albery 1948-2001 sought promote non-technological innovations institute emerged informal network social centers info-services spread around london throughout 1970s one earliests centers bit information service founded 1968 john hoppy hopkins years coordinator bit nicholas albery came idea institute would promote kinds ideas experimentations developed mainly inside called alternative society institute known different names institute social innovations institute social change denominations revolved around concept new improvements made within situation mainstream society goes time considered merged global ideas bank formed 1995
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Databases
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matrixx software matrixx software digital commerce platform company matrixx software founded jennifer kyriakakis dave labuda 2009 labuda serves company cto ceo kyriakakis serves company vp marketing company based saratoga california matrixx produces digital commerce platform used large telecom companies management operations support systems business support systems runs premises private cloud/nfv environments public cloud one focus company aid billing daily transactions processed mobile devices attempting improve cost/revenue margin billing client companies matrixx also polls mobile users regarding views mobile telecom companies 2016 matrixx received 5 million financing pldt capital acquiring 4 company 2018 company raised 40 million series c round funding led sutter hill ventures investors including ck hutchison holdings bringing company total financing 100 million investors company included venture capital arms telstra swisscom
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Distributed computing architecture
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tombs amp treasure tombs treasure known japan adventure game originally developed nihon falcom 1986 pc-8801 pc-9801 fm-7 msx 2 x1 japanese computer systems famicom/nes version released 1988 altered story-based featured new music role-playing elements english-language nes version published infocom 1991 japanese enhanced remakes released saturn windows systems 1998 1999 respectively game takes place ancient mayan city chichen itza yucatán peninsula alternates using three-quarters overhead view travelling ruin ruin switching first-person perspective upon entering specific location start game player allowed name protagonist young brown-haired man lead female green-haired lass daughter one professor imes names manually entered game randomly choose pre-coded list names characters professor imes renowned archaeologist investigating artifact known sun key potentially ability unlock greatest secrets lost mayan civilization rumored housed somewhere within chichen itza however latest expedition team mysteriously disappeared exploring different temples dates june 22 july 14 guide josé able escape unharmed return artifacts team found hoping help player quest find professor three talking professor secretary anne travel mexico ancient city look clues several actual sites chichen itza explored player although interiors purposes purposefully changed slightly order help create atmosphere fantasy mystery-solving intrigue furthermore ruin home demon said control creature known tentacula although speculation gathered professor notes josé say player start tombs treasure predominantly solving puzzles interacting objects one another found throughout mayan city travelling temple temple available action walk using d-pad however temple entered player may start exploring much thoroughly using list picture-based action keys go push wash etc characters interact environment inspecting clues manipulating unlock another area elsewhere several items collect well whose purpose learned looking game gives three characters—the boy girl josé—their special attributes let contribute quest boy player in-game avatar usually hands-on work girl talented musically josé strong able move things two however light turn-based combat also faces player demon encountered inside ruin encounters almost always happen first room ruin although exceptions fighting accomplished simply enough using fight command although means player using bare hands equipping sword done fight selecting use highlighting sword inventory first battles strictly turn-based means healing simply bashing away monster one dead however possible run away fight go command player fully healed comes back try battle later game uses simplistic experience point system gives player additional levels hit points winning battles successfully solving puzzles throughout chichen itza player kept advancing far early simply wo n't strong enough yet contend higher-level monsters sure encounter although occasionally player may defeated despite strong enough game also came packaged small guide represented professor journal written awkward cursive form hard understand well speaking riddles often aid player read correctly ruins strictly show entered vast majority
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Computer architecture
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privatecore privatecore venture-backed startup located palo alto california develops software secure server data server attestation memory encryption company attestation memory encryption technology fills gap exists “ data motion ” encryption tls email encryption “ data rest ” encryption disk encryption tape encryption protecting “ data use ” random access memory privatecore memory encryption technology protects threats servers cold boot attacks hardware advanced persistent threats rootkits/bootkits computer hardware supply chain attacks physical threats servers insiders privatecore acquired facebook deal announced 7 august 2014 privatecore founded 2011 security veterans vmware google seed funding foundation capital privatecore “ virtualizes ” physical security enables service providers enterprises deploy servers processing sensitive data outsourced environments maintaining security around data use company memory encryption technology spurred number industry trends including increasing sophistication hackers larger number servers outsourced environments larger amounts sensitive data placed persistent memory x86 virtualization technology increase environment attack surface privatecore acquired facebook deal announced 7 august 2014 privatecore focus securing data-in-use x86 servers company taken advantage recent microprocessor innovations including larger microprocessor caches hardware cryptographic acceleration technology enable effective methods encrypting memory maintaining acceptable application performance technology approach goes beyond previous academic research efforts tresor privatecore assumes element need trusted system central processing unit cpu firm uses trusted platform module tpm chips intel trusted execution technology intel txt provide remote server attestation privatecore also supports cryptographic hardware acceleration provided intel aes-ni technology privatecore technology positioned applicable outsourced hosted environments enterprise trust compute infrastructure privatecore vcage product portfolio comprises vcage manager vcage host vcage manager validates integrity x86 servers running linux well vcage host vcage host installs bare-metal servers provides hardened hypervisor based kvm secure server random access memory ram aes encryption vcage host loading secure hypervisor cpu cache acting gateway encrypt memory paging cpu cache ram vcage memory encryption leverages kvm hypervisor also potential support hypervisors vcage host supports existing kvm management tools vcage supports number use cases including creating openstack trusted computing pools well protecting x86 servers co-location bare-metal cloud environments vcage manager vcage host became generally available 11 february 2014
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Computer security
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notification center notification center feature ios macos provides overview alerts applications displays notifications user completes associated action rather requiring instant resolution users may choose applications appear notification center handled initially released ios 5 october 2011 notification center made available macs part os x mountain lion july 2012 notification center released ios 5 replace previous system dealing push local notifications instead interrupting user alert notification center instead displays banner top screen allows user continue using device disappears set period time previous notifications collated notification center panel displayed ios dragging status bar os x clicking notification center button using track-pad gestures swiping right left notifications may selected user redirects user application notification initially created marking alert read notification read removed panel users may also remove notifications without reading deleting individual alerts dismissing application alerts within application generating ios device locked new notifications appear lock screen users may access application generating alert swiping application icon finger left right along notification notification center iphone ipod touch also includes weather stocks widgets displaying information weather user current location stocks user selected stocks application feature available ipad os x release ios 7 added weather widget ipad notification center users also select option display twitter facebook buttons allowing send tweets update status directly notification center ios 7 however option send tweets update facebook statuses removed application uses push notifications system provided apple local notifications may use notification center users may customise want appear notification center may opt stop certain applications appearing center sending alerts screen os x users may also disable alerts banners day stopping notifications appearing screen however notifications sent time still visible notification center panel similar service included ios 6 part disturb feature
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Operating systems
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zendian problem zendian problem exercise communication intelligence operations mainly traffic analysis cryptanalysis devised lambros d. callimahos part advanced course ca-400 callimahos taught national security agency cryptanalysts starting 1950s scenario involves 375 radio messages said intercepted december 23 us army contingent united nations force landed fictional island zendia pacific ocean typical intercept looks like message first line provided intercept operator giving call signs frequency time reference number rest message transcript morse code transmission beginning intercepted message header consists 8 four-digit groups initially meaning numeric header known meanings various components header serial number assigned transmitting organization message center worked traffic analysis rest message consists indicators ciphertext first group evidently discriminant indicating cryptosystem used depending cryptosystem second group may contain message-specific keying element initial rotor settings first two groups repeated end message allows correction garbled indicators remaining characters encrypted text since transmissions always use complete groups nulls may used pad text cryptosystems employed include transposition dinome rotor-based ciphers one-part code successfully tackled without use computer solution easy practical exercise reinforces many basic principles including ways exploit collection message traffic certain amount cleartext inter-operator chatter also provided may help analysis headers discriminants also given intercepts next three days may used traffic analysis determining daily operating procedures zendian problem declassified available either part military cryptanalytics book published reprints aegean park press walnut creek ca usa small differences ciphertext sources neither entirely error-free indeed errors intentional dealing part learning process karl heinz-everts web site provides link downloadable archive intercepts site also provides analysis partial solutions viewed anyone wishing learn working exercise cryptanalists successfully finished ca-400 became members dundee society society founded lambros d. callimahos named empty dundee marmalade jar desk could n't disclose society real purpose large print showing fictional nation zendia hangs wall library national cryptologic museum operated nsa copies map shrunken degree feature labels illegible appear previously cited books
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Computer security
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camel application part camel application part cap signalling protocol used intelligent network architecture cap remote operations service element rose user protocol layered top transaction capabilities application part tcap ss 7 protocol suite cap based subset etsi core allows implementation carrier-grade value added services unified messaging prepaid fraud control freephone gsm voice gprs data networks camel means adding intelligent applications mobile rather fixed networks builds upon established practices fixed line telephony business generally classed heading intelligent network application part inap cs-2 protocol camel application part cap portable software provides mechanisms support operator services beyond standard gsm services subscribers roaming within outside home plmn hplmn cap product extends framework gsm/3g networks implementing in-based services within gsm/3g networks camel used subscriber roaming networks allowing home network monitor control calls made subscriber camel provides services prepaid roaming services fraud control special numbers e.g. 123 voicemail works everywhere closed user groups e.g. office extension numbers work everywhere camel cap defined four phases accompanying specification builds upon previous phase cap phase provides message set procedures needed support corresponding camel phase requirements defined 3gpp ts 22.078 service aspects 3gpp ts 23.078 technical realization definition protocol may considered split three sections
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Internet protocols
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firestarter firewall firestarter personal firewall tool uses netfilter iptables/ipchains system built linux kernel ability control inbound outbound connections firestarter provides graphical interface configuring firewall rules settings provides real-time monitoring network traffic system firestarter also provides facilities port forwarding internet connection sharing dhcp service firestarter free open-source software uses gui widgets gtk+
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Computer security
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socket fs1 socket fs1 notebooks using amd apu processors codenamed llano trinity richland socket fs1r2 llano -branded products combine k10 cedar vliw5 uvd 3 video acceleration amd eyefinity-based multi-monitor support three displayport-monitors trinity richland -branded products piledriver northern islands vliw4 uvd 3 vce 1 video acceleration amd eyefinity-based multi-monitor support four displayport-monitors amd desktop cpus available 722-pin package socket am1 fs1b clear whether desktop cpus compatible socket fs1 vice versa
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Computer architecture
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temp file cleaner temp file cleaner tfc utility program microsoft windows designed quickly remove temporary unnecessary files might otherwise prove difficult find dynamic paths multiple locations tfc minimilist design single purpose allow compact installation version 3.1.1 full installation occupies 3.7mb supports removal unnecessary temporary files created google chrome mozilla firefox internet explorer opera browsers well created course normal system operation windows updates cache windows logs windows root user temp files created variety programs addition tfc includes ability customize operations include deeper search subdirectories brute force deletion root path specification addition advanced cleaning protocols windows debug files hibernation files system restore data tfc allows test run operation offering users ability preview files would deleted upon normal execution well amount space would freed
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Computer file systems
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anomaly-based intrusion detection system anomaly-based intrusion detection system intrusion detection system detecting network computer intrusions misuse monitoring system activity classifying either normal anomalous classification based heuristics rules rather patterns signatures attempts detect type misuse falls normal system operation opposed signature-based systems detect attacks signature previously created order positively identify attack traffic system must taught recognize normal system activity two phases majority anomaly detection systems consist training phase profile normal behaviors built testing phase current traffic compared profile created training phase anomalies detected several ways often artificial intelligence type techniques systems using artificial neural networks used great effect another method define normal usage system comprises using strict mathematical model flag deviation attack known strict anomaly detection techniques used detect anomalies include data mining methods grammar based methods artificial immune system network-based anomalous intrusion detection systems often provide second line defense detect anomalous traffic physical network layers passed firewall security appliance border network host-based anomalous intrusion detection systems one last layers defense reside computer end points allow fine-tuned granular protection end points application level anomaly-based intrusion detection network host levels shortcomings namely high false-positive rate ability fooled correctly delivered attack attempts made address issues techniques used payl mcpad
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Computer security
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indus os indus os formerly known firstouch indian mobile operating system based android currently available english 23 indian regional languages spoken 95 indian population active user base 10 million company app marketplace app bazaar 400,000 apps indus os partnered phone brands gionee itel micromax_informatics intex technologies karbonn mobiles celkon swipe elite trio mobiles indus os founded 2015 rakesh deshmukh akash dongre sudheer b three alumni indian institute technology bombay hari padmanabhan iit kanpur alumni industry veteran serial entrepreneur seed investor company indus os raised total 13 million series funding led omidyar network jsw ventures ventureast company also funded among others angel investors mayank singhal temasek holdings pranay chulet founder quikr amit gupta naveen tewari co-founders inmobi kunal bahl rohit bansal co-founders snapdeal may 2015 micromax_informatics started shipping latest version unite 3 unite series smartphones firstouch os operating system available english 10 indian languages key feature operating system swipe-to-translate indus swipe helped users translate transliterate english text regional languages operating system also app marketplace app bazaar 5000 applications regional languages popular application marketplace microsoft skype available popular indian regional languages including hindi december 2015 firstouch announced collaboration government india ministry electronics information technology previously known department electronics deity introduce text-to-speech technology regional languages operating system regional app marketplace app bazaar integrated carrier billing facility hence allows users download apps regional languages without requiring email id paying credit cards 90 indus os users activated app bazaar smartphones 75 use monthly basis app bazaar 50000 applications regional languages operating system features english 23 regional languages assamese bengali gujarati hindi kannada malayalam marathi odia punjabi tamil telugu urdu company patented keyboard allows word prediction matra prediction auto correction swipe-to-translate transliterate features users indus os offices mumbai delhi dhaka currently 70-member team company also plans open office china effort partner international smartphone brands operating system received positive review firstpost tech2 rehan hooda review intex aqua supre+ claimed indus os shining factor otherwise ordinary smartphone abhishek baxi android authority review operating system said unlike stock android custom android skins support indian languages indus os menu items icon texts et al appear chosen regional language big win app bazaar support carrier billing allowing users download paid apps games via mobile balance pre-paid get billed post-paid ’ mighty convenient consumers great motivator app developers publishers indus os economic times telecom award 2016 innovation developing oem product category may 7 2016 indus os declared second popular os india according research study conducted counterpoint research may 2016 os second popular india 7.6 market share greater market share microsoft apple android remains popular 82.3 indus os awarded prestigious tie50 silicon valley top start-up award year 2016 et telecom award 2016 'innovation development oem product indus os 'digital startup year award drivers digital awards 2016 nasscom announced indus os one top 10 startups india nasscom product conclave 2016 company also awarded aegis graham bell award digital india category alongside vodafone india year 2016 gsma nominated indus os annual global mobile awards mobile world congress barcelona 2017 category best mobile innovation emerging markets indus os brand year award technology category world consulting research corporation mumbai december 21 2016 mint newspaper mit technology review named akash dongre co-founder chief product officer indus os one top innovators age 35 india emtech 2017 event indus os also named superbrand super startups awarded 30+ innovative business models india october 2017 indus os awarded confederation indian industry industrial innovation award one top 10 startup india company story also documented case study ivey publishing also distributed harvard business review
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Operating systems
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dell fluid file system dell fluid file system fluidfs shared-disk filesystem made dell provides distributed file systems clients customers buy appliance combination purpose-built network-attached storage nas controllers integrated primary backup power supplies i.e. appliance attached block level storage via iscsi fiber channel protocol single dell fluidfs appliance consists two controllers operating concert i.e. active/active connecting back-end storage area network san depending storage capacity requirements user preference fluidfs version 4 nas appliances used compellent equallogic san arrays equallogic fs7600 fs7610 connect client network dell equallogic arrays either 1 gbit/s fs7600 10 gbit/s fs7610 iscsi protocol compellent fluidfs available either 1 gbit/s 10 gbit/s iscsi connectivity client network connection backend compellent san either 8 gbit/s fibre channel 10 gbit/s iscsi fluidfs software layer running nas appliance creates single name-space users offering access via server message block smb network file system nfs also includes features prevent data-loss corruption uses caching increase performance fluidfs result dell acquisition intellectual property exanet firm whose assets included hardware-independent scalable nas storage product previously known dell scalable file system dsfs dell changed name fluidfs acquisition compellent successfully used fluid data tag-line startup company dell developed exanet file system support ndmp backup integrated ip obtained acquisition ocarina networks included deduplication data compression technology dell initially adapted fluidfs work compellent equallogic powervault storage platforms underlying software architecture fluidfs employs linux-based symmetric clustering model distributed metadata native load balancing flexible caching capabilities features scalability limited volume size traditional file systems supports scaling adding capacity system scaling adding nodes performance system fluidfs operates across symmetric cluster purpose-built nas controllers housed pairs within 2u appliance interface fabric shared back-end storage via iscsi fibre channel storage area networks fluidfs architecture layered presents traditional file system network clients performing special functions back end designed utilize available resources network server disk levels improve response times based back-end storage product maximum number nas appliances storage capacity varies number nas appliances varies 1 4 entire capacity system managed single global namespace fluidfs v6 supports multitenancy total storage capacity tens pb maximum size single file 128 tb number files name-space limited 64 billion per appliance 256 billion 4 appliances making one largest industry
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Computer file systems
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air-gap malware air-gap malware malware designed defeat air-gap isolation secure computer systems using various air-gap covert channels one techniques successfully demonstrated scientists fraunhofer society november 2013 modern computers especially laptops built-in microphones speakers air-gap malware designed communicate secure information acoustically frequencies near beyond limit human hearing technique limited computers close physical proximity also limited requirement transmitting receiving machines infected proper malware form communication link physical proximity limit overcome creating acoustically linked mesh network effective mesh network ultimately traditional ethernet connection outside world secure information removed secure facility 2014 researchers introduced ″airhopper″ bifurcated attack pattern showing feasibility data exfiltration isolated computer nearby mobile phone using fm frequency signals 2015 bitwhisper covert signaling channel air-gapped computers using thermal manipulations introduced bitwhisper supports bidirectional communication requires additional dedicated peripheral hardware later 2015 researchers introduced gsmem method exfiltrating data air-gapped computers cellular frequencies transmission generated standard internal bus renders computer small cellular transmitter antenna 2016 researchers categorized various out-of-band covert channels oob-ccs malware communication channels require specialized hardware transmitter receiver oob-ccs high-bandwidth conventional radio-frequency channels however capable leaking sensitive information require low data rates communicate e.g. text recorded audio cryptographic key material general researchers demonstrated air-gap covert channels realized number different mediums including
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Computer security
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impromptu programming environment impromptu mac os x programming environment live coding impromptu built around scheme language member lisp family languages source code core opened extempore project environment allows make changes program runtime variables functions may redefined changes take effect immediately programmer also create schedule code future execution well data events notes graphics objects event scheduled execution continues looping performed using idiom called temporal recursion works function asynchronously schedule future call final action library allows communicating audio units audio synthesis graphics layers quicktime quartz core image opengl video composition code written objective-c called editor also objective-c frameworks perform calls scheme interpreter impromptu scheme interpreter initially built tinyscheme 1.35 baseline substantially modified since better suit live coding context real-time garbage collector objective-c integration added also new statically typed language called extempore language integrated system language syntactically scheme-like semantically closer c designed real-time sound synthesis computationally heavy tasks provides type inference compiled machine language llvm study keith live coding performance impromptu andrew sorensen first two minutes 1:56 silent performer writes program produce introduction piece modifies code fly evolve composition core impromptu released extempore bsd style licence runs linux mac os x includes scheme interpreter extempore language compiler scheduler bindings apple libraries absent environment interface dynamic libraries
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Programming language topics
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quip software quip collaborative productivity software suite mobile web allows groups people create edit documents spreadsheets group typically business purposes quip founded bret taylor co-creator google maps ceo friendfeed former facebook cto along kevin gibbs founded google app engine taylor founded company 2012 leaving position facebook roughly year later quip launched public mobile-centric tool creating shared notes lists documents app well-received winning accolades one best apps year time next web guardian 2015 quip announced received 30 million funding round led greylock partners july 2016 salesforce announced acquisition quip estimated total 750 million january 2017 quip acquired designer studio unity variety core quip provides word processing spreadsheet functionality accessible via web ios app android app alongside documents quip live updating history edits made well ability highlight portions document add comments facilitates collaboration 2015 quip also added standalone chat rooms
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Distributed computing architecture
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alec yasinsac alec yasinsac dean school computing university south alabama united states retired u.s. marine yasinsac awarded doctoral degree 1996 university virginia doctoral advisor william wulf received master science computer science naval postgraduate school bachelor science mathematics appalachian state university yasinsac co-founder co-director security assurance information security sait laboratory visiting scholar national academy engineering nae 2006 served advisory board nae 2007 national meeting symposium electronic voting led team conducted source code review support florida department state audit florida 13th congressional district 2006 election
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Computer security
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xos mobile operating system xos pronounced eks-oh-es customized version android mobile operating system developed mobile phone company infinix mobile ltd succeeding infinix previous operating system xui xos designed evolving creative smartphone operating system shipped infinix smart phones three distinctive features ai intelligence lightning speed customization option 50 million smartphone devices powered xos currently improved 1000 times attain 21 faster performance compared original android os xos also provides 20 apps redesigned satisfy users needs
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Operating systems
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socket 940 socket 940 940-pin socket 64-bit amd opteron server processors amd athlon 64 fx consumer processors socket entirely square shape pins arranged grid exception four key pins used align processor corners amd opteron older amd athlon 64 fx fx-51 use socket 940 microprocessors designed socket intended used server platform provide additional features provide additional robustness one feature acceptance registered memory recent 940-pin socket am2 visually similar one two electrically incompatible due integrated memory controller socket 940 cpu integrate ddr controller whereas am2 models use ddr2 controller
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Computer architecture
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ios 5 ios 5 fifth major release ios mobile operating system developed apple inc. successor ios 4 announced company worldwide developers conference june 6 2011 released october 12 2011 succeeded ios 6 september 19 2012. ios 5 revamped notifications adding temporary banners appear top screen introducing notification center central location recent notifications operating system also added icloud apple cloud storage service synchronization content data across icloud-enabled devices imessage apple instant messaging service first time system software updates installed wirelessly without requiring computer itunes ios 5 also featured deep integration twitter introduced multitasking gestures ipads added easily accessible camera shortcut lock screen ios 5 subject criticism iphone 4s users initial release poor battery life failures sim cards echoes phone calls problems fixed subsequent releases ios 5 introduced apple worldwide developers conference june 6 2011 beta version available developers later day ios 5 officially released october 12 2011. ios 5.0.1 released november 10 2011 first update ios 5 update included fixes battery issues ios 5.1 released march 7 2012 along new ipad retina display update included support japanese language siri redesigned camera app ipad bug fixes battery life issues ios 5.1.1 released may 7 2012 update included reliability improvements high dynamic range photos safari bookmark synchronization fixes bug fixes previous ios versions notifications popped screen dialog boxes interrupting current activity ios 5 notifications revamped show temporary banner top screen recent notifications also accessed pulling notification center top screen users prefer old notification system keep choosing appropriate option settings menu ios 5 introduces icloud apple cloud storage service new service allows users synchronize music pictures videos application data across icloud-enabled devices ios 5 enables wireless system updates supported devices meaning computer itunes n't necessary update devices activation new devices updates done wirelessly ios 5 features deep twitter integration users able sign twitter directly settings menu photos tweeted directly photos camera apps users also able tweet safari youtube google maps apps multitasking gestures debut ipad release ios 5 multitasking allows users jump apps without double-tapping home button first going home screen multitasking gestures available ipad 2 ipad keyboard could undocked bottom screen could split two half-keyboards first ios 5 release allowed camera app easily accessed lock screen first time users double-clicked home button camera icon would appear next slide unlock message users would click directly access camera ios 5.1 update streamlined process dropping home button double-click procedure requiring users swipe camera icon security purposes device locked passcode method accessing camera allows access camera app features device pressing volume-up button allows user take picture imessage new instant messaging service built messages app allowed anyone ios 5 device send basic multimedia messages anyone else compatible ios 5 device contrast sms messages sent imessage use internet rather regular cellular texting also contrast regular sms android blackberry devices compatible service imessages synchronized across user devices color-coded blue regular sms green ios mail app included rich text formatting better indent control flagging messages ability drag addresses cc bcc lines reminders allows users create lists tasks alerts either date-based location-based newsstand act native app rather special folder selected shows icons periodicals user subscribed newspapers magazines new issues downloaded automatically ipod app replaced separate music videos apps initial october 2011 release ios 5 saw significant upgrade issues errors installation apple server overload following user complaints apple officially confirmed ios 5 poor battery life iphone 4s users stated upcoming software update would fix issues ios 5.0.1 update fixed bugs related battery issues november 2011 engadget reported ios 5 update caused wi-fi connection drops users report also wrote recent ios 5.0.1 update certainly n't fixed matter either questioned whether events unrelated part larger issue users iphone 4s reported issues sim card ios 5 given error messages invalid sim sim failure apple released second software build 5.0.1 update designed fix sim card issues users iphone 4s reported random appearance echoes phone calls made earphones initial release ios 5 party call sometimes unable hear conversation due problem many aspects ios 5 received positive reviews including new notification center ability sync update wirelessly imessage richmond shane telegraph said ios 5 brilliant upgrade already brilliant operating system different people look different things mobile operating system people prefer blackberry android windows mobile value ease use attention detail design ios 5 apple continues deliver best user experience available richard goodwin know mobile said reckon ios 5 everything needs ’ wait get teeth stuck soon ’ released autumn 2011 release apple dropped support older devices specifically iphone 3g second-generation ipod touch
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Operating systems
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ia-64 ia-64 also called intel itanium architecture instruction set architecture isa itanium family 64-bit intel microprocessors basic isa specification originated hewlett-packard hp evolved implemented new processor microarchitecture intel hp continued partnership expertise underlying epic design concepts order establish first new isa 20 years bring entirely new product line market intel made massive investment product definition design software development tools os software industry partnerships marketing support effort intel created largest design team history new marketing industry enabling team completely separate x86 first itanium processor codenamed merced released 2001 itanium architecture based explicit instruction-level parallelism compiler decides instructions execute parallel contrasts superscalar architectures depend processor manage instruction dependencies runtime itanium models including tukwila cores execute six instructions per clock cycle 2008 itanium fourth-most deployed microprocessor architecture enterprise-class systems behind x86-64 power isa sparc 1989 hp began become concerned reduced instruction set computing risc architectures approaching processing limit one instruction per cycle intel hp researchers exploring computer architecture options future designs separately began investigating new concept known long instruction word vliw came research yale university early 1980s vliw computer architecture concept like risc cisc single instruction word contains multiple instructions encoded one long instruction word facilitate processor executing multiple instructions clock cycle typical vliw implementations rely heavily sophisticated compilers determine compile time instructions executed time proper scheduling instructions execution also help predict direction branch operations value approach useful work fewer clock cycles simplify processor instruction scheduling branch prediction hardware requirements penalty increased processor complexity cost energy consumption exchange faster execution time hp begun believe longer cost-effective individual enterprise systems companies develop proprietary microprocessors intel also researching several architectural options going beyond x86 isa address high end enterprise server high performance computing hpc requirements thus intel hp partnered 1994 develop ia-64 isa using variation vliw design concepts intel named explicitly parallel instruction computing epic intel goal leverage expertise hp developed early vliw work along develop volume product line targeted high-end enterprise class servers high performance computing hpc systems could sold original equipment manufacturers oems hp wished able purchase off-the-shelf processors built using intel volume manufacturing leading edge process technology higher performance cost effective current pa-risc processors resulting products would intel hp would one many customers order achieve volumes necessary successful product line itanium products would required meet needs broader customer base software applications os development tools available customers required itanium products designed documented manufactured quality support consistent rest intel products therefore intel took lead microarchitecture design productization packaging test steps industry software operating system enabling linux windows nt marketing part intel definition marketing process engaged wide variety enterprise oem software os vendors well end customers order understand requirements ensure reflected product family meet needs broad range customers end-users hp made substantial contribution isa definition merced/itanium microarchitecture itanium 2 productization responsibility intel original goal delivering first itanium family product codenamed merced 1998 intel product marketing industry engagement efforts substantial achieved design wins majority enterprise server oem including based risc processors time industry analysts predicted ia-64 would dominate servers workstations high-end desktops eventually supplant risc complex instruction set computing cisc architectures general-purpose applications compaq silicon graphics decided abandon development alpha mips architectures respectively favor migrating ia-64 1997 apparent ia-64 architecture compiler much difficult implement originally thought delivery itanium began slipping since itanium first ever epic processor development effort encountered unanticipated problems team accustomed addition epic concept depends compiler capabilities never implemented research needed several groups developed operating systems architecture including microsoft windows unix unix-like systems linux hp-ux freebsd solaris tru64 unix monterey/64 last three canceled reaching market 1999 intel led formation open source industry consortium port linux ia-64 named trillium later renamed trillian due trademark issue led intel included caldera systems cern cygnus solutions hewlett-packard ibm red hat sgi suse turbolinux va linux systems result working ia-64 linux delivered ahead schedule first os run new itanium processors intel announced official name processor itanium october 4 1999 within hours name itanic coined usenet newsgroup pun name titanic unsinkable ocean liner sank maiden voyage 1912 time itanium released june 2001 performance superior competing risc cisc processors recognizing lack software could serious problem future intel made thousands early systems available independent software vendors isvs stimulate development hp intel brought next-generation itanium 2 processor market year later itanium 2 processor released 2002 relieved many performance problems original itanium processor mostly caused inefficient memory subsystem 2003 amd released opteron implemented 64-bit architecture x86-64 opteron gained rapid acceptance enterprise server space provided easy upgrade x86 intel responded implementing x86-64 em64t xeon microprocessors 2004 november 2005 major itanium server manufacturers joined intel number software vendors form itanium solutions alliance promote architecture accelerate software porting 2006 intel delivered montecito marketed itanium 2 9000 series dual-core processor roughly doubled performance decreased energy consumption 20 percent itanium 9300 series processor codenamed tukwila released 8 february 2010 greater performance memory capacity tukwila originally slated release 2007 device uses 65 nm process includes two four cores 24 mb on-die caches hyper-threading technology integrated memory controllers implements double-device data correction dddc helps fix memory errors tukwila also implements intel quickpath interconnect qpi replace itanium bus-based architecture peak interprocessor bandwidth 96 gb/s peak memory bandwidth 34 gb/s quickpath processor integrated memory controllers interfaces memory directly using qpi interfaces directly connect processors i/o hubs quickpath also used intel processors using nehalem microarchitecture making probable tukwila nehalem able use chipsets tukwila incorporates four memory controllers supports multiple ddr3 dimms via separate memory controller much like nehalem-based xeon processor code-named beckton itanium 9500 series processor codenamed poulson follow-on processor tukwila features eight cores 12-wide issue architecture multithreading enhancements new instructions take advantage parallelism especially virtualization poulson l3 cache size 32 mb l2 cache size 6 mb 512 kb 256 kb per core die size 544 mm² less predecessor tukwila 698.75 mm² isscc 2011 intel presented paper called 32nm 3.1 billion transistor 12-wide-issue itanium processor mission critical servers given intel history disclosing details itanium microprocessors isscc paper likely refers poulson analyst david kanter speculates poulson use new microarchitecture advanced form multi-threading uses many two threads improve performance single threaded multi-threaded workloads new information released hotchips conference new information presents improvements multithreading resiliency improvements instruction replay ras new instructions thread priority integer instruction cache prefetching data access hints kittson 9500 poulson slightly higher clocked january 2019 intel announced kittson would discontinued last order date january 2020 planned successor intel extensively documented itanium instruction set technical press provided overviews architecture renamed several times history hp originally called pa-wideword intel later called ia-64 itanium processor architecture ipa settling intel itanium architecture still widely referred ia-64 64-bit register-rich explicitly parallel architecture base data word 64 bits byte-addressable logical address space 2 bytes architecture implements predication speculation branch prediction uses variable-sized register windowing parameter passing mechanism also used permit parallel execution loops speculation prediction predication renaming control compiler instruction word includes extra bits approach distinguishing characteristic architecture architecture implements large number registers 128-bit instruction word called bundle contains three slots holding 41-bit instruction plus 5-bit template indicating type instruction slot types m-unit memory instructions i-unit integer alu non-alu integer long immediate extended instructions f-unit floating-point instructions b-unit branch long branch extended instructions template also encodes stops indicate data dependency exists data stop instructions pair stops constitute instruction group regardless bundling must free many types data dependencies knowledge allows processor execute instructions parallel without perform complicated data analysis since analysis already done instructions written within slot instructions predicated specifying predicate register value true false determine whether instruction executed predicated instructions always execute predicated codice_4 always reads true ia-64 assembly language instruction format deliberately designed written mainly compilers humans instructions must grouped bundles three ensuring three instructions match allowed template instructions must issue stops certain types data dependencies stops also used limited places according allowed templates fetch mechanism read two bundles per clock l1 cache pipeline compiler take maximum advantage processor execute six instructions per clock cycle processor thirty functional execution units eleven groups unit execute particular subset instruction set unit executes rate one instruction per cycle unless execution stalls waiting data units group execute identical subsets instruction set common instructions executed multiple units execution unit groups include ideally compiler often group instructions sets six execute time since floating-point units implement multiply–accumulate operation single floating point instruction perform work two instructions application requires multiply followed add common scientific processing occurs processor execute four flops per cycle example 800 mhz itanium theoretical rating 3.2 gflops fastest itanium 2 1.67 ghz rated 6.67 gflops practice processor may often underutilized slots filled useful instructions due e.g data dependencies limitations available bundle templates densest possible code requires 42.6 bits per instruction compared 32 bits per instruction traditional risc processors time no-ops due wasted slots decrease density code additional instructions speculative loads hints branches cache difficult generate optimally even modern compilers 2002 2006 itanium 2 processors shared common cache hierarchy 16 kb level 1 instruction cache 16 kb level 1 data cache l2 cache unified instruction data 256 kb level 3 cache also unified varied size 1.5 mb 24 mb 256 kb l2 cache contains sufficient logic handle semaphore operations without disturbing main arithmetic logic unit alu main memory accessed bus off-chip chipset itanium 2 bus initially called mckinley bus usually referred itanium bus speed bus increased steadily new processor releases bus transfers 2×128 bits per clock cycle 200 mhz mckinley bus transferred 6.4 gb/s 533 mhz montecito bus transfers 17.056 gb/s itanium processors released prior 2006 hardware support ia-32 architecture permit support legacy server applications performance ia-32 code much worse native code also worse performance contemporaneous x86 processors 2005 intel developed ia-32 execution layer ia-32 el software emulator provides better performance montecito intel therefore eliminated hardware support ia-32 code 2006 release montecito intel made number enhancements basic processor architecture including see chipsets ... markets
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Computer architecture
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hacking art exploitation hacking art exploitation book jon smibbs erickson computer security network security published starch press 2003 second edition 2008 examples book developed compiled tested gentoo linux jon erickson computer security expert background computer science 2011 worked vulnerability researcher computer security specialist california bootable cd included book provides linux-based programming debugging environment users content exploiting moves programming networking cryptography book use notable measure real-world examples discussions rarely bring specific worms exploits computer programming portion hacking takes half book section goes development design construction testing exploit code thus involves basic assembly programming demonstrated attacks range simple buffer overflows stack complex techniques involving overwriting global offset table erickson discusses countermeasures non-executable stack evade return-to-libc attacks dive deeper matters without known guaranteed exploits address space layout randomization book also cover openwall grsecurity pax projects kernel exploits networking segment hacking explains basics osi model basic networking concepts including packet sniffing connection hijacking denial service port scanning cryptology section hacking covers basic information theory addition symmetric asymmetric encryption winds cracking wep utilizing fluhrer mantin shamir attack besides basics including man-in-the-middle attacks dictionary attacks use john ripper hacking discusses quantum key distribution lov grover quantum search algorithm peter shor quantum factoring algorithm breaking rsa encryption using large quantum computer introduction book states hacking done within confines law productive reasons programming chapter book different types programs described shown via examples chapter covers control structures basic aspects programming live cd provides environment reader follow along examples book programming exploitation taking computer code set rules changing computer want finding ways holes system change important part exploitation chapter covers exploit techniques memory corruption buffer overflows format strings especially using perl bash shellcode osi model communication among computers networking osi model used osi model model provides standards computers use communicate seven layers osi model physical layer data-link layer network layer transport layer session layer presentation layer application layer packet computer sends another computer must go layer osi model sockets standard way communicate network use computer operating systems socket socket used programmer create way send receive data using layers osi two types sockets stream socket datagram socket stream sockets use transmission control protocol tcp datagram socket uses user datagram protocol udp peeling back layers 'peeling back layers describes osi layers actually work osi model described great detail images book make easy understand network sniffing switched unswitched networks exist networking switched network uses devices called switches analyze tell packets travelling network endpoint unswitched network free flow packets without stopped analyzed sniffing refers using program allows see packets network going denial service denial service attack attempt make computer resource unavailable intended users means denial service attack sends large quantity communication requests intended resource order overflow resource becomes unusable certain period time types attacks usually directed routers firewalls order shut gain access computers network router susceptible types attacks firewall usually handle attack unaffected distributed denial service attack communication requests come multiple computers greatly increasing number requests regular denial service attack types dos attacks include ping death teardrop ping flooding amplification attacks tcp/ip hijacking tcp/ip hijacking another way uses spoofed packets take connection victim host machine technique mainly used collect passwords host machine uses password connected type attack takes place victim attacker must network another form tcp/ip hijacking rst hijacking involves injecting fake reset packet port scanning port scanning simply way figure ports accepting listening connections hacker would use program lets know ports open scanning ports network trying open many type scans syn idle fin x-mas null scans reach hack someone part finding vulnerabilities typecasting network using debugger go lines code used network protocols efficient way accomplish shellcode used exploitation code like hacker code wants run gains control program usually hacker find exploit programs code able insert code shellcode found exploit assembly vs. c assembly differs c assembly low-level programming language processed communicate directly processor using c high-level programming language code must compiled sent kernel making system call making call processor words almost like taking system calling kernel picture using assembly path shellcode part shellcode inject program shellcode taken many examples code book ways accomplish task self-spawning shellcode spawning shellcode code enabled exploit found shellcode able run vulnerability found program best way accomplish shown book making sure code small port-binding shellcode type shellcode attaches network port bound port listen tcp connection finds tcp connection lot programming involved shown vividly book connect-back shellcode type shellcode mainly used getting around firewalls firewalls going block port-binding shellcode working set allow known services active ports connect-back shellcode initiates connection back hacker ip address coming firewall instead going code book depicts connect-back use shellcode ways accomplish part book defenses intrusion prevention systems stop known hacking exploits countermeasures detect administrator network aware exploit may occurring using certain tools like reading logs packet sniffing network ways catch exploits occur system daemons system daemon server program unix system receives accepts incoming connections daemon program runs background detaches controlling terminal certain way point book code shown run daemon program signals also used unix-based environment make operating system calls signal type terminal immediately send interrupt message complete task whatever signal typed uses signals displayed coding examples book tools trade hacker certain set tools needs help exploiting exploit script tool uses already written exploit code find holes system program using exploit scripts easy even non-hacker use code already written couple exams exploit tools shown book use log files stated earlier log files way check events happening computer network hacker ability change log file says help noticed code directions change log files book overlooking obvious another sign program hacked longer work correctly time programs work correctly hacker modified accomplish another task skilled hacker however modify program still works correctly wants program exploited ways tell happened finding program exploited tedious process since usually starts taking parts program looking individually putting exploited program back together see exploited shown book advanced camouflage hacker exploiting program ip address written log file camouflaging log files ip address detected shown book ip address hidden called spoofing ip address whole infrastructure use intrusion detection systems intrusion prevention systems greatly helps avoid risk exploited even firewalls routers log files show evidence hacking making sure outbound tcp connections processed one way limit found ways shown book use tcp connections easier go undetected payload smuggling using shellcode exploit programs caught intrusion detection systems usually intrusion detection system catch programs already written noticeable shell code exploit programs caught real hackers using ways hide shellcode harder detect couple examples hide shellcode found book buffer restrictions sometimes restrictions put buffers vulnerabilities exploited ways book depicts get around buffer restrictions hardening countermeasures exploits found book around long time took hackers figured take advantage vulnerabilities described book memory corruption change control use shellcode three easiest steps exploitation nonexecutable stack applications use stack type executing one defense make stack non-executable buffer overflows used exploitation program defense effective stopping use shellcode application however way get around use non-executable stack shown described book randomized stack space randomized stack type countermeasure used hacker unable tell shellcode implemented randomizes memory layout within stack also way get around countermeasure examples book cryptology use communicating secretly use ciphers cryptanalysis process cracking deciphering secret communications chapter offers information theory cryptology including work claude shannon concepts including unconditional security one-time pads quantum key distribution computational security using key encrypt decrypt messages symmetric encryption asymmetric encryption involves using different keys public private chapter gives examples kinds encryption use cipher encryption algorithm combining use symmetric cipher asymmetric cipher called hybrid cipher ways attack ciphers get around encryption methods shown described book chapter also shows methods figure encrypted passwords including brute-force attacks hash look-ups also offers methods get around wireless 802.11b wi-fi wired equivalent privacy wep encryption
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Computer security
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e2fsprogs e2fsprogs sometimes called e2fs programs set utilities maintaining ext2 ext3 ext4 file systems since file systems often default linux distributions commonly considered essential software included e2fsprogs ordered asciibetical order many utilities based codice_20 library despite name might suggest e2fsprogs works ext2 also ext3 ext4 although ext3 journaling capability reduce need use codice_7 sometimes still necessary help protect kernel bugs bad hardware ext4 e2fsck runtime come considerably userspace companion ext2 ext3 ext4 drivers linux kernel e2fsprogs commonly used gnu/linux however ported systems freebsd darwin
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Computer file systems
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john a. samford john alexander samford august 29 1905 – december 1 1968 lieutenant general united states air force served director national security agency samford born hagerman new mexico 1905 graduated high school 1922 spent one year columbia university new york city 1924 received senatorial appointment united states military academy graduated 1928 131st class 260 samford first assignment student officer brooks field texas 1929 received pilot wings kelly field eventually rated command pilot samford next assigned fort crockett located galveston texas 1930 returned kelly field served flying instructor 1934 ordered engineering armament school chanute field illinois 1935 1942 held various assignments panama virginia louisiana florida samford assistant chief staff g-1 headquarters third air force tampa florida appointed chief staff viii air force composite command located northern ireland 1943 samford appointed deputy chief staff eighth air force later chief staff viii bomber command 1944 samford promoted brigadier general appointed chief staff eighth air force october 1944 appointed deputy assistant chief staff a-2 headquarters u.s. army air forces january 1947 samford appointed commander 24th composite wing soon thereafter became antilles air division caribbean air command may 1949 samford appointed commandant air command staff school promoted major general 1950 held brief appointment commandant air war college appointed director intelligence united states air force samford tenure director air force intelligence project blue book investigated unidentified flying objects ufos started july 29 1952 stamford conducted press conference pentagon related ufos samford mentioned beginning 1956 film ufo examined phenomena unidentified flying objects samford served vice director national security agency june august 1956 november samford appointed director national security agency promoted lieutenant general held post retirement november 23 1960 successor nsa director admiral laurence h. frost died november 20 1968 washington dc
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Computer security
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interarchy interarchy ftp client macos supporting ftp sftp scp webdav amazon s3 made nolobe supports many advanced features transferring syncing managing files internet interarchy created mac programmer peter n lewis 1993 macintosh system 7 lewis went form stairways software 1995 continue development interarchy 2007 lewis sold interarchy matthew drayton nolobe continues develop interarchy day drayton employee stairways software worked developer interarchy alongside lewis since 2001 interarchy originally called anarchie archie client name changed interarchy 2000 due conflict cybersquatter
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Internet protocols
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libressl libressl open-source implementation transport layer security tls protocol implementation named secure sockets layer ssl deprecated predecessor tls support removed release 2.3.0 openbsd project forked libressl openssl 1.0.1g april 2014 response heartbleed security vulnerability goals modernizing codebase improving security applying development best practices heartbleed security vulnerability discovered openssl openbsd team audited codebase decided necessary fork openssl remove dangerous code libressl.org domain registered 11 april 2014 project announced name 22 april 2014 first week development 90,000 lines c code removed unused code removed support obsolete operating systems removed libressl initially developed intended replacement openssl openbsd 5.6 ported platforms stripped-down version library stable project seeking stable commitment external funding 17 may 2014 bob beck presented libressl first 30 days future holds 2014 bsdcan conference described progress made first month 5 june 2014 several openssl bugs became public several projects notified advance libressl theo de raadt accused openssl developers intentionally withholding information openbsd libressl 20 june 2014 google created another fork openssl called boringssl promised exchange fixes libressl google already relicensed contributions isc license requested libressl developers 21 june 2014 theo de raadt welcomed boringssl outlined plans libressl-portable starting 8 july code porting macos solaris began initial porting linux began 20 june libressl default provider tls libressl selectable provider tls changes include replacement custom memory calls ones standard library example codice_1 codice_2 codice_3 codice_4 etc. process may help later catch buffer overflow errors advanced memory analysis tools observing program crashes via aslr use nx bit stack canaries etc. fixes potential double free scenarios also cited vcs commit logs including explicit assignments null pointer values extra sanity checks also cited commit logs related ensuring length arguments unsigned-to-signed variable assignments pointer values method returns order maintain good programming practice number compiler options flags designed safety enabled default help spotting potential issues fixed earlier -wall -werror -wextra -wuninitialized also code readability updates help future contributors verifying program correctness knf white-space line-wrapping etc. modification removal unneeded method wrappers macros also help code readability auditing error i/o abstraction library references changes made ensure libressl year 2038 compatible along maintaining portability similar platforms addition codice_5 codice_6 calls added prevent compiler optimizing prevent attackers reading previously allocated memory changes help ensure proper seeding random number generator-based methods via replacements insecure seeding practices taking advantage features offered kernel natively terms notable additions made openbsd added support newer reputable algorithms chacha stream cipher poly1305 message authentication code along safer set elliptic curves brainpool curves rfc 5639 512 bits strength initial release libressl added number features chacha poly1305 algorithm brainpool anssi elliptic curves aes-gcm chacha20-poly1305 aead modes later versions added following initial release libressl disabled number features default code features later removed including kerberos us-export ciphers tls compression dtls heartbeat ssl v2 ssl v3 later versions disabled features initial release libressl removed number features deemed insecure unnecessary deprecated part openbsd 5.6 dual ec drbg algorithm suspected back door cut along support fips 140-2 standard required unused protocols insecure algorithms also removed including support fips 140-2 md4/md5 j-pake srp one complaints openssl number open bugs reported bug tracker gone unfixed years older bugs fixed libressl
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Operating systems
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snappy package manager snappy software deployment package management system developed canonical linux operating system packages called snaps tool using snapd work across range linux distributions allowing distro-agnostic upstream software packaging snappy originally designed ubuntu touch system designed work internet things cloud desktop computing snapcraft tool developing snap packages snap application packages software self-contained work across range linux distributions unlike traditional linux package management approaches like apt yum require specifically adapted packages linux distribution therefore adding delay application development deployment end-users snaps dependency app store obtained source therefore used upstream software deployment snaps deployed ubuntu versions linux ubuntu app store used default back-end stores enabled well developers use snaps create command line tools background services well desktop applications snap application upgrades via atomic operation deltas possible june 2016 snapd ported wide range linux distributions enable snaps used across linux distribution all-snap ubuntu core snapd also available progress arch linux centos debian fedora solus manjaro linux linux mint openembedded raspbian openwrt opensuse distribution able interpret snap metadata implement security expectations snap distribution-specific fashion snapcraft tool developers package programs snap format snappy snap file format single compressed filesystem based squashfs format mounted dynamically host operating system together declarative metadata interpreted snap system set appropriately shaped secure sandbox container application file format extension .snap snappy packaging deployed internet things environments ranging consumer-facing products enterprise device management gateways snappy included default ubuntu desktop images version 16.04 onwards developer screen capture tool peek discontinued support snap packages continuing support flatpak appimage stating developers systems administrators voiced complaints snap highly unsuitable mission-critical applications since autoupdates turned basic feature missing design choice snap developers led unexpected downtime services restart buggy software enters snap distribution system red hat employee adam williamson acknowledging bias criticized snap keeping server side closed source mechanism using third party servers sign contributor license agreement contribute development
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Operating systems
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install party des savoie install party des savoie kind installfest social event aims popularize linux operating system libre software day people pays de savoie savoy upper savoy departements welcomed get familiar new desktop environment linux renowned ability reliable virus-free thus local public many ways discover concept free software traditionally install party des savoie takes place may various cities amongst two savoys instance annecy chambery 2010 edition local non-profit societies agu3l alpinux marmottux take active part organisation specific installfest 2011install party des savoie took place may 21 chambery jean-jacques rousseau media librairy lugs savoy gathered together linux mint debian edition lmde system adopted presented public live dvd installed computers first time france attempt visioconferencing made two different installfeists via videoconferencing tools ekiga xmpp protocol
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Operating systems
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hardware scout hardware scout technique uses otherwise idle processor execution resources perform prefetching cache misses thread stalled cache miss processor pipeline checkpoints register file switches runahead mode continues issue instructions thread waiting memory thread execution run-ahead mode known scout thread data returns memory processor restores register file contents checkpoint switches back normal execution mode computation run-ahead mode discarded processor nevertheless scouting provides speedup memory level parallelism mlp increased cache lines brought cache hierarchy often used processor switches back normal mode sun rock processor later canceled used form hardware scout however computations run-ahead mode depend cache miss may retired immediately allows prefetching traditional instruction-level parallelism scouting simultaneous multithreading smt use hardware threads fight memory wall scouting scout thread runs instructions instruction stream instruction causes pipeline stall case smt smt thread executes instruction another context thus smt increases throughput processor scouting increases performance lowering number cache misses
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Computer architecture
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object type object-oriented programming computer science object type a.k.a wrapping object datatype used object-oriented programming wrap non-object type make look like dynamic object object-oriented programming languages make distinction reference value types often referred objects non-objects platforms complex value types n't exist reasons runtime efficiency syntax semantic issues example java primitive wrapper classes corresponding primitive type etc languages like c++ little notion reference type thus use object type little interest boxing otherwise known wrapping process placing primitive type within object primitive used reference object example java change size array must fixed size one might desire class lists references dynamic objects—it list primitive types value types circumvent boxed dynamic objects added using generic parameterized types introduced j2se 5.0 type represented hand c primitive wrapper classes allows boxing value type returning generic reference boxed object always copy value object usually immutable unboxing object also returns copy stored value repeated boxing unboxing objects severe performance impact boxing dynamically allocates new objects unboxing boxed value longer used makes eligible garbage collection however modern garbage collectors default java hotspot garbage collector efficiently collect short-lived objects boxed objects short-lived performance impact may bad direct equivalence unboxed primitive type reference immutable boxed object type fact possible substitute primitive types program boxed object types whereas assignment one primitive another copy value assignment one reference boxed object another copy reference value refer object first reference however cause problems objects immutable semantically real difference two references object different objects unless look physical equality operations assignment arithmetic comparison logical operators one unbox boxed type perform operation re-box result needed thus possible store primitive types autoboxing term getting reference type value type type conversion either implicit explicit compiler automatically supplies extra source code creates object example versions java prior j2se 5.0 following code compile compilers prior 5.0 would accept last line reference objects surface different forth convert one manually instantiate integer object j2se 5.0 compiler accept last line automatically transform integer object created store value means j2se 5.0 something like compile b unboxed integer values summed result autoboxed new finally stored inside variable equality operators used way equality operators already defined reference types equality references test equality value boxed type one must still manually unbox compare primitives use method another example j2se 5.0 allows programmer treat collection contained values instead objects contradict said collection still contains references dynamic objects list primitive types must instead however compiler automatically transforms code list silently receive objects source code mentions primitive values example programmer write think added list compiler actually transformed line unboxing refers getting value associated given object type conversion either implicit explicit compiler automatically supplies extra source code retrieves value object either invoking method object means example versions java prior j2se 5.0 following code compile c n't support automatic unboxing meaning java n't separate set primitive types object types types primitive object version java automatically implemented c compiler either primitive value types object reference types languages automatic boxing downcast automatically i.e following code wo n't compile c java modern object pascal yet another way perform operations simple types close boxing called type helpers freepascal record helpers delphi freepascal delphi mode. br dialects mentioned object pascal compile-to-native languages miss features c java implement notably run-time type inference strongly typed variables. br feature related boxing. br allows programmer use constructs like
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Programming language topics
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lpc programming language lpc short lars pensjö c object-oriented programming language derived c developed originally lars pensjö facilitate mud building lpmuds though designed game development flexibility led used variety purposes evolution language pike lpc syntax places family c-like languages c c++ strongest influences almost everything lpc object however lpc precisely use concept class mudos something called class really struct instead lpc objects blueprint objects clones blueprint objects prototype-based programming model one treat blueprint object much class object-oriented languages object variables attributes functions methods variables store object state functions executable routines called object object uniquely defined name file comes plus clone numeric identifier typical implementation clone file codice_1 third clone created current run session codice_2 blueprint object corresponding codice_1 simply codice_4 mud game common objects include rooms weapons armor non-player character npcs mudlibs define inheritable objects common things lpmud 2.4.5 mudlib example parent object rooms codice_5 lpc possible syntactically declare class-only instance-only methods attributes functions variables may accessed identically blueprints clones example codice_6 would call codice_7 function directly blueprint instance codice_8 however controversial mechanism many drivers called shadowing allows instance methods emulated extent permitting one object overlay function set onto another effect interposing external function calls shadowed object direct external access variables also supported interaction objects carried function calls notwithstanding data structures pointed variables independent objects changes visible objects referencing data structures simultaneously drivers privileged functions allowing cumbersome form external variable access permits inspection mutation lpc generally used code muds 'rooms often created objects store information describing particular scene along exits point room objects common usage lpc uses game related possible following example shows simple traditional room leverages functions defined mudlib object codice_5 however mudlibs define determine rooms way method defining room first line tells object inherit functionality codice_5 object example assumes codice_5 object defines functions codice_12 codice_13 example contains single function codice_14 drivers call set call codice_14 allow object initialize startup values standard constructor case example calls functions set basic room attributes inherited codice_5 functions called highly dependent mudlib use since mudlib defines actual room parent drivers also support applying type modifiers inherit statements causing inherited object behave respect inheritor type modifier applied functions and/or variables appropriate term object variable used means variable element object i.e attribute opposed local variable exists within function block global variable nonexistent lpc — someone speaks global variable reference lpc probably mean object variable primitive lpc types int string status float etc passed value data structure types object array mapping class struct passed reference feature powerful also lead security holes muds people building world generally less trusted staff running game object passes mapping sensitive values like access control information author another object modify thus increase access rights mudlib developers server administrators thus careful passing complex types lower access objects lpc environments generally categorize functions several major types according implemented lpc implementations generally master object specific lpc object loaded first lpc driver essentially controls happen past point master object typically tell driver simul_efun object preload objects need present startup define functions called object loaded otherwise configure driver operation driver refer back master object needs interact central point reference running environment accepting network connections handling errors validating attempts perform privileged operations
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Programming language topics
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gordon blake gordon aylesworth blake july 22 1910 – september 1 1997 lieutenant general united states air force served director national security agency 1962 1965 gordon aylesworth blake born charles city iowa july 22 1910 son george cecelia blake graduated high school charles city appointed united states military academy late gilbert n. haugen 1927 graduating june 11 1931 commissioned second lieutenant coast artillery corps detailed student officer pilot training october 1932 blake completed primary advanced flying schools transferred air corps january 25 1933 assigned pursuit squadron barksdale field louisiana entering signal school fort monmouth new jersey july 1934 completed communications officers course following june assigned communications instructor air corps technical school chanute field illinois going hawaii february 1939 blake communications officer 18th composite wing september 1941 acted communications officer first land-based aircraft flight hawaii philippines flight made b-17 bombers sent philippines reinforcements flew pioneer route – midway island wake island port moresby new guinea darwin australia clark field philippine islands members flight awarded distinguished flying cross december 7 1941 blake base operations officer rank major hickam field japanese attack pearl harbor awarded silver star gallantry action day became operations officer seventh air force base command promoted lieutenant colonel spent first months world war ii supervising operation airplane ferry route australia via christmas island – canton island – fiji – new caledonia october 1942 blake shifted back communications work commanded army airways communications system pacific rest world war ii exception period october 1943 january 1944 temporary duty alaska established air communications office alaska promoted colonel november 1942 august 28 1945 accompanied special 150-man task force japan prepare airborne occupation troop landings august 30 work world war ii blake awarded legion merit admiral chester w. nimitz plus oak leaf cluster legion merit war department air medal oak leaf cluster battle stars participation following campaigns central pacific eastern mandates new guinea north solomons guadalcanal papua south philippines luzon western pacific returned overseas november 1945 january 1946 appointed deputy commander airways air communications service langley field virginia entering air war college maxwell air force base alabama august 1947 blake graduated following june went research development work wright-patterson air force base ohio 1948 1951 electronics subdivision engineering division served chief armament laboratory summer 1951 placed charge 12 development laboratories promoted brigadier general final assignment wright field vice-commander june 1952 january 1953 transferred air force headquarters january 1953 blake appointed deputy director communications office deputy chief staff operations becoming director communications following month many changes united states air force system global communications navigation including pioneer operational circuits using tropospheric scatter communications first time carried tour director communications blake named assistant deputy chief staff operations june 2 1956 capacity served permanent joint board defense canada — us many defense projects dewline radar network planned two countries latter part washington assignment given aeronautical rating command pilot promoted major general highest permanent rank regular service blake left washington january 4 1957 become commander united states air force security service major component united states air force headquarters san antonio texas awarded air force distinguished service medal exceptionally meritorious conduct performance outstanding service command september 1 1959 blake assigned vice-commander-in-chief chief staff pacific air forces air arm joint pacific command headquarters hawaii blake came headquarters continental air command july 1961 commander-designate assumed command continental air command september 30 1961 became lieutenant general october 1 1961 blake assumed position director national security agency fort george g. meade maryland july 1 1962 held retirement 1965 us air force aircraft save award named awarded action taken air traffic controller airfield manager results safe recovery imperiled airborne aircraft help given endangered aircraft ground
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Computer security
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java bytecode instruction listings list instructions make java bytecode abstract machine language ultimately executed java virtual machine java bytecode generated languages running java platform notably java programming language note referenced value refers 32-bit int per java instruction set
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Computer architecture
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hack programming language hack programming language hiphop virtual machine hhvm created facebook dialect php language implementation open-source licensed mit license hack allows programmers use dynamic typing static typing kind type system called gradual typing also implemented programming languages actionscript hack type system allows types specified function arguments function return values class properties however types local variables always inferred specified hack introduced march 20 2014 announcement new programming language facebook already implemented code battle tested large portion web site hack designed interoperate seamlessly php widely used open-source scripting language focus web development embedded html majority valid php scripts also valid hack however numerous less frequently used php features language constructs supported hack hack extends type hinting available php 5 introduction static typing adding new type hints example scalar types integer string well extending use type hints example class properties function return values however types local variables specified since hack uses gradual typing system default mode type annotations mandatory even places inferred type system assume author correct admit code however strict mode available requires annotations thus enforces fully sound code basic file structure hack script similar php script changes hack file n't include codice_1 opening markup tag forbids using top-level declarations thus would need write code within entrypoint function entrypoint functions automatically executed top-level file automatically executed file included via include require autoloader like functions hack function names must unique within project – i.e projects multiple entrypoints call main « __entrypoint » function main void script similar php executed following output sent browser hello world important point note unlike php hack html code mix normally mix php html code together file like html /html type code supported hack either xhp another template engine needs used hack allows types specified function arguments function return values functions hack thus annotated types like following // hack functions annotated types function negate bool x bool
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Programming language topics
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fortress programming language fortress discontinued experimental programming language high-performance computing created sun microsystems funding darpa high productivity computing systems project one language designers guy l. steele jr. whose previous work includes scheme common lisp java name fortress intended connote secure fortran i.e. language high-performance computation provides abstraction type safety par modern programming language principles language features included implicit parallelism unicode support concrete syntax similar mathematical notation language designed similar fortran syntactically resembles scala standard ml haskell fortress designed outset multiple syntactic stylesheets source code rendered ascii text unicode prettied image would allow support mathematical symbols symbols rendered output easier reading emacs-based tool called fortify transforms ascii-based fortress source code latex output fortress also designed highly parallel rich functionality contained within libraries drawing java example codice_1 loop construct parallel operation would necessarily iterate strictly linear manner depending underlying implementation however codice_1 construct library function could replaced another version programmer liking rather built language fortress designers made syntax close possible pseudocode analyzed hundreds computer science mathematics papers courses books journals using pseudocode extract common usage patterns english language standard mathematical notation used represent algorithms pseudocode made compiler trying maintain one-to-one correspondence pseudocode executable fortress fortress one three languages created funding high productivity computing systems project others x10 ibm chapel cray inc november 2006 darpa approved funding third phase hpcs project x10 chapel funded fortress leading uncertainty future fortress january 2007 fortress transformed open-source project open-source community people outside sun write fortress code test using open-source fortress interpreter version 1.0 fortress language specification released april 2008 along compliant implementation targeting java virtual machine july 2012 steele announced active development fortress would cease brief winding-down period citing complications using fortress type system existing virtual machines fortress version archetypal hello world program presented fortress reference card export statement makes program executable every executable program fortress must implement run function file program saved compilation must name one specified initial component statement println function outputs hello world words screen
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Programming language topics
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integration platform integration platform software integrates different applications services differentiates enterprise application integration focus supply chain management uses idea system integration create environment engineers integration platforms built components purchased pre-built product ready installation procured integration platform service ipaas offering integration platform tries create environment engineers integration platform typically contains set functional components integration platform focus designed helpful engineers intention map business processes integrate tools supply chain management therefore related systems
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Computer architecture
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voodoo chat voodoo chat opened late december 2001 text-based chat program voice chat features created wake excite virtual places closure due company bankruptcy following acquisition home network impending closure excite virtual places new chat venue needed house soon displaced users service initially chief software engineer excite chat service tom lang proposed subscription based service using virtual places software received response lotus software regarding license two months without word subscription based service idea considered dead development alternative chat venue mike parniak using original software rather existing virtual places software began mid-2001 two months creation would later known voodoo chat lang finally received word would granted license use virtual places subscription based service development voodoo chat continued despite removal lang obstacles first version chat opened december 2001 originally voodoo chat run server hierarchy within overlay network today service works little differently voodoo chat apart text-based chatting system also avatars images representing oneself displayed top screen foreground web page said images size width height though programs defaults set 300x300 file size limit 15kb images also effects supported in-house flipping rotating turning black white inverting pixelating blur grow shrink october 9 2007 voice chat come current version voodoo sequenced voice chat works sending clips 20 seconds voice users chat room non-real-time even streamed voice chat 'realtime given high latency typically encountered 'seems likewise nobody tests expressed feeling things 'out sync problematic way voodoo chat uses two methods security first encryption second use system hashes voodoo method encryption encrypts transfers data program increase privacy deter hackers far according website none cracked protocol plenty tried voodoo client generates set system hashes pieces serial numbers within hardware users computer gathered program starts transmitted user attempts log users hashes checked global hash ban list king checked banned hash list specific server 're logging system hash matches either ban list user barred service
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Internet protocols
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motherboard motherboard sometimes alternatively known mainboard main circuit board system board baseboard planar board logic board colloquially mobo main printed circuit board pcb found general purpose computers expandable systems holds allows communication many crucial electronic components system central processing unit cpu memory provides connectors peripherals unlike backplane motherboard usually contains significant sub-systems central processor chipset input/output memory controllers interface connectors components integrated general purpose use applications motherboard specifically refers pcb expansion capability name suggests board often referred mother components attached often include peripherals interface cards daughtercards sound cards video cards network cards hard drives forms persistent storage tv tuner cards cards providing extra usb firewire slots variety custom components similarly term mainboard applied devices single board additional expansions capability controlling boards laser printers televisions washing machines mobile phones embedded systems limited expansion abilities prior invention microprocessor digital computer consisted multiple printed circuit boards card-cage case components connected backplane set interconnected sockets old designs copper wires discrete connections card connector pins printed circuit boards soon became standard practice central processing unit cpu memory peripherals housed individual printed circuit boards plugged backplane ubiquitous s-100 bus 1970s example type backplane system popular computers 1980s apple ii ibm pc published schematic diagrams documentation permitted rapid reverse-engineering third-party replacement motherboards usually intended building new computers compatible exemplars many motherboards offered additional performance features used upgrade manufacturer original equipment late 1980s early 1990s became economical move increasing number peripheral functions onto motherboard late 1980s personal computer motherboards began include single ics also called super i/o chips capable supporting set low-speed peripherals keyboard mouse floppy disk drive serial ports parallel ports late 1990s many personal computer motherboards included consumer-grade embedded audio video storage networking functions without need expansion cards higher-end systems 3d gaming computer graphics typically retained graphics card separate component business pcs workstations servers likely need expansion cards either robust functions higher speeds systems often fewer embedded components laptop notebook computers developed 1990s integrated common peripherals even included motherboards upgradeable components trend would continue smaller systems introduced turn century like tablet computer netbook memory processors network controllers power source storage would integrated systems motherboard provides electrical connections components system communicate unlike backplane also contains central processing unit hosts subsystems devices typical desktop computer microprocessor main memory essential components connected motherboard components external storage controllers video display sound peripheral devices may attached motherboard plug-in cards via cables modern microcomputers increasingly common integrate peripherals motherboard important component motherboard microprocessor supporting chipset provides supporting interfaces cpu various buses external components chipset determines extent features capabilities motherboard modern motherboards include additionally nearly motherboards include logic connectors support commonly used input devices usb mouse devices keyboards early personal computers apple ii ibm pc included minimal peripheral support motherboard occasionally video interface hardware also integrated motherboard example apple ii rarely ibm-compatible computers ibm pc jr. additional peripherals disk controllers serial ports provided expansion cards given high thermal design power high-speed computer cpus components modern motherboards nearly always include heat sinks mounting points fans dissipate excess heat motherboards produced variety sizes shape called computer form factor specific individual computer manufacturers however motherboards used ibm-compatible systems designed fit various case sizes desktop computer motherboards use atx standard form factor — even found macintosh sun computers built commodity components case motherboard power supply unit psu form factor must match though smaller form factor motherboards family fit larger cases example atx case usually accommodate microatx motherboard.computers generally use highly integrated miniaturized customized motherboards one reasons laptop computers difficult upgrade expensive repair often failure one laptop component requires replacement entire motherboard usually expensive desktop motherboard cpu socket central processing unit slot electrical component attaches printed circuit board pcb designed house cpu also called microprocessor special type integrated circuit socket designed high pin counts cpu socket provides many functions including physical structure support cpu support heat sink facilitating replacement well reducing cost importantly forming electrical interface cpu pcb cpu sockets motherboard often found desktop server computers laptops typically use surface mount cpus particularly based intel x86 architecture cpu socket type motherboard chipset must support cpu series speed steadily declining costs size integrated circuits possible include support many peripherals motherboard combining many functions one pcb physical size total cost system may reduced highly integrated motherboards thus especially popular small form factor budget computers typical motherboard different number connections depending standard form factor standard modern atx motherboard typically two three pci-express 16x connection graphics card one two legacy pci slots various expansion cards one two pci-e 1x superseded pci standard eatx motherboard two four pci-e 16x connection graphics cards varying number pci pci-e 1x slots sometimes also pci-e 4x slot vary brands models motherboards two pci-e 16x slots allow 2 monitors without special hardware use special graphics technology called sli nvidia crossfire amd allow 2 4 graphics cards linked together allow better performance intensive graphical computing tasks gaming video editing etc motherboards generally air cooled heat sinks often mounted larger chips northbridge modern motherboards insufficient improper cooling cause damage internal components computer cause crash passive cooling single fan mounted power supply sufficient many desktop computer cpu late 1990s since required cpu fans mounted heat sinks due rising clock speeds power consumption motherboards connectors additional computer fans integrated temperature sensors detect motherboard cpu temperatures controllable fan connectors bios operating system use regulate fan speed alternatively computers use water cooling system instead many fans small form factor computers home theater pcs designed quiet energy-efficient operation boast fan-less designs typically requires use low-power cpu well careful layout motherboard components allow heat sink placement 2003 study found spurious computer crashes general reliability issues ranging screen image distortions i/o read/write errors attributed software peripheral hardware aging capacitors pc motherboards ultimately shown result faulty electrolyte formulation issue termed capacitor plague standard motherboards use electrolytic capacitors filter dc power distributed around board capacitors age temperature-dependent rate water based electrolytes slowly evaporate lead loss capacitance subsequent motherboard malfunctions due voltage instabilities capacitors rated 2000 hours operation expected design life roughly doubles every lifetime 3 4 years expected however many manufacturers deliver substandard capacitors significantly reduce life expectancy inadequate case cooling elevated temperatures around cpu socket exacerbate problem top blowers motherboard components kept effectively doubling motherboard lifetime mid-range high-end motherboards hand use solid capacitors exclusively every 10 °c less average lifespan multiplied approximately three resulting 6-times higher lifetime expectancy capacitors may rated 5000 10000 12000 hours operation extending projected lifetime comparison standard solid capacitors motherboards contain non-volatile memory initialize system load startup software usually operating system external peripheral device microcomputers apple ii ibm pc used rom chips mounted sockets motherboard power-up central processor would load program counter address boot rom start executing instructions rom instructions initialized tested system hardware displayed system information screen performed ram checks loaded initial program peripheral device none available computer would perform tasks memory stores display error message depending model design computer rom version example apple ii original ibm pc microsoft cassette basic rom would start program could loaded disk modern motherboard designs use bios stored eeprom chip soldered socketed motherboard boot operating system non-operating system boot programs still supported modern ibm pc-descended machines nowadays assumed boot program complex operating system microsoft windows linux power first supplied motherboard bios firmware tests configures memory circuitry peripherals power-on self test post may include testing following things recent motherboards bios may also patch central processor microcode bios detects installed cpu one errata published many motherboards use update bios called uefi
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Computer architecture
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dillo dillo minimalistic web browser particularly intended older slower computers embedded systems supports plain html/xhtml css rendering images http scripting ignored entirely current versions dillo run linux bsd os x irix cygwin due small size browser choice several space-conscious linux distributions released gnu general public license dillo free software chilean software engineer jorge arellano cid conceived dillo project late 1999 publishing first version dillo december year primary goal creating dillo democratize access information arellano cid believed one buy new computer pay broadband order enjoy world wide web end designed dillo small fast efficient capable performing well even intel 80486 cpu dial-up internet access dillo originally written c programming language gtk+ gui toolkit first versions based earlier browser called armadillo hence name dillo 2 written c c++ components fast light toolkit fltk released october 14 2008 text antialiasing support character sets latin-1 http compression capability improved page rendering added move fltk gtk+ also removed many project dependencies reduced dillo memory footprint 50 2011 dillo-3.x released using fltk-1.3 according changelog change prompted part lack official release fltk-2 stopped dillo-2 inclusion lightweight distributions would otherwise suitable jorge arellano cid still dillo lead developer today dillo funded private donations efforts obtain public grants corporate sponsors unsuccessful lack funding led slowdown development 2006 complete stop 2007 project restarted 2008 two months later received €115 donation distrowatch features dillo include bookmarks tabbed browsing support jpeg png including alpha transparency gif images partial support css introduced release 2.1 settings default fonts background color downloads folder home page customizable configuration files cookies supported disabled default due privacy concerns web browsers retain web cache history program closed dillo automatically clears improve privacy performance developer tool called bug meter provided lower-right corner clicked displays information validation problems unclosed tags dillo found web page unlike browsers dillo quirks mode improve compatibility web pages use invalid html instead dillo processes web pages according published web standards 2003 two linux enthusiasts successfully ran dillo intel 486 processor demonstrated even meager hardware dillo could render http //news.bbc.co.uk/ 10–15 seconds furthermore dillo run variety software platforms including linux bsd solaris mac os x dos handheld devices however dillo developers made little effort make browser work microsoft windows arellano cid stated windows goes dillo goal democratization artificially increasing hardware requirements software costs nevertheless dillo reported work windows via cygwin additionally dillo-win32 project port dillo windows defunct d+ browser dplus continues dillo-win32 left forked final dillo-win32 release 3.0p9 attempt maintain upstream compatibility dillo last version 0.5b oct 15 2013 dillo support javascript java flash right-to-left text complex text layout support frames also limited dillo presents link frame allow user view one time plug-in add https support likewise development reviews dillo praised extraordinary speed noted speed comes price visible cost dillo inability display complex web pages meant 2008 review linux.com commented dillo user interface may intimidating new users pointed scarcity plug-ins dillo dillo global usage share less one hundredth one percent many deficiencies attributed simple lack manpower behind development dillo however browser choice several space-conscious linux distributions damn small linux feather linux vectorlinux antix mustang linux
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Internet protocols
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