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Windows Server 2012	active directory windows server number changes active directory version shipped windows server r. active directory domain services installation wizard replaced new section server manager gui added active directory recycle bin.multiple password policies set domain.active directory windows server aware changes resulting virtualization virtualized domain controllers safely cloned.upgrades domain functional level windows server simplified performed entirely server manager.active directory federation services longer required downloaded installed role claims used active directory federation services introduced kerberos token.
Windows Server 2012	windows powershell commands used active directory administrative center viewed powershell history viewer.hyperv windows server along windows includes new version hyperv presented microsoft build event.many new features added hyperv including network virtualization multitenancy storage resource pools crosspremises connectivity cloud backup.additionally many former restrictions resource consumption greatly lifted.virtual machine version hyperv access virtual processors terabyte memory terabytes virtual disk space per virtual hard disk using new .vhdx format.
Windows Server 2012	virtual machines active per host active per failover cluster.slat required processor feature hyperv windows windows server required supplementary remotefx role.refs resilient file system refs codenamed protogon new file system windows server initially intended file servers improves ntfs respects.major new features refs includeimproved reliability ondisk structuresrefs uses b trees ondisk structures including metadata file data.metadata file data organized tables similar relational database.
Windows Server 2012	file size number files folder total volume size number folders volume limited bit numbers result refs supports maximum file size exabytes maximum .× folders maximum volume size yottabyte kb clusters allows large scalability practical limits file folder size hardware restrictions still apply.free space counted hierarchical allocator includes three separate tables large medium small chunks.file names file paths limited kb unicode text string.builtin resiliencerefs employs allocationonwrite update strategy metadata allocates new chunks every update transaction uses large io batches.refs metadata builtin bit checksums stored independently.
Windows Server 2012	file data optional checksum separate integrity stream case file update strategy also implements allocationonwrite controlled new integrity attribute applicable files directories.nevertheless file data metadata becomes corrupt file deleted without taking whole volume offline.result builtin resiliency administrators need periodically run errorchecking tools chkdsk using refs.compatibility existing apis technologiesrefs require new system apis file system filters continue work refs volumes.refs supports many existing windows ntfs features bitlocker encryption access control lists usn journal change notifications symbolic links junction points mount points reparse points volume snapshots file ids oplock.refs seamlessly integrates storage spaces storage virtualization layer allows data mirroring striping well sharing storage pools machines.
Windows Server 2012	refs resiliency features enhance mirroring feature provided storage spaces detect whether mirrored copies files become corrupt using background data scrubbing process periodically reads mirror copies verifies checksums replaces bad copies good ones.some ntfs features supported refs including object ids short names file compression file level encryption efs user data transactions hard links extended attributes disk quotas.sparse files supported.support named streams implemented windows windows server though later added windows .windows server r. refs offer data deduplication.dynamic disks mirrored striped volumes replaced mirrored striped storage pools provided storage spaces.
Windows Server 2012	windows server automated errorcorrection integrity streams supported mirrored spaces automatic recovery parity spaces added windows .windows server r. booting refs supported either.iis .windows server includes version .internet information services iis.
Windows Server 2012	new version contains new features sni cpu usage caps particular websites centralized management ssl certificates websocket support improved support numa substantial changes made.remote desktop protocol .remote desktop protocol new functions adaptive graphics progressive rendering related techniques automatic selection tcp udp transport protocol multi touch support directx support vgpu usb redirection supported independently vgpu support etc.connection quality button displayed rdp client connection bar rdp .connections clicking provides information connection including whether udp use not.
Windows Server 2012	scalability windows server supports following maximum hardware specifications.windows server improves predecessor windows server r system requirements windows server support itanium runs x processors.upgrades windows server windows server r supported although upgrades prior releases not.editions windows server four editions foundation essentials standard datacenter.reception reviews windows server generally positive.simon bisson zdnet described ready datacenter today tim anderson register said move towards greater modularity stronger automation improved virtualisation makes perfect sense world public private clouds remarked said capability windows deliver obscure timeconsuming errors unchanged concluded nevertheless strong upgrade overall.infoworld noted server use windows panned metro user interface countered microsofts increasing emphasis server core mode fleshed new depth easeofuse features increased use practically mandatory powershell.
Windows Server 2012	however michael otey windows pro expressed dislike new metro interface lack ability use older desktop interface alone saying users windows server manage servers using graphical user interface rather powershell.paul ferrill wrote windows server essentials provides pieces necessary provide centralized file storage client backups remote access tim anderson contended many businesses using sbs earlier want stick citing absence exchange lack ability synchronize active directory federation services user limit paul thurott wrote choose foundation least incompany staff andor comfortable outsourcing management microsoft partner solution provider essentials mind ideal modern startup people.windows server r second release windows server r derived windows .codebase released manufacturing august became generally available october microsoft.service pack formally designated windows server r update released april .see also comparison microsoft windows versionscomparison operating systemshistory microsoft windowslist operating systemsmicrosoft servers notes extended security updates microsoft announced july distribute extended security updates sql server windows server windows server r maximum three years end extended support date.
Windows Server 2012	end support microsoft originally planned end support windows server windows server r january order provide customers standard transition lifecycle timeline microsoft extended windows server r support march months.final set end date windows server end extended support october .references reading stanek william .windows server inside out.microsoft press.
Windows Server 2012	isbn .stanek william .windows server r inside volume configuration storage essentials.microsoft press.isbn .stanek william .windows server r inside volume services security infrastructure.
Apache Ignite	microsoft press.isbn .external links official websitewindows server r windows server technetwindows server r msdnwindows server msdntutorials lab manual articles windows server rdisk tier optional enabled hold full data set whereas memory tier cache full partial data set depending capacity.data ignite stored form keyvalue pairs.database component distributes keyvalue pairs across cluster way every node owns portion overall data set.data rebalanced automatically whenever node added removed cluster.apache ignite cluster deployed onpremise commodity hardware cloud e.g.microsoft azure aws google compute engine containerized provisioning environments kubernetes docker apache mesos vmware.history us company us company founded nikita ivanov dmitriy setrakyan pleasanton california.
Apache Ignite	funding round million disclosed november .by located foster city california disclosed funding million.gridgain made core technology opensource software .accepted apache incubator program october .ignite project graduated september .clustering apache ignite clustering component uses shared nothing architecture.server nodes storage computational units cluster hold data indexes process incoming requests along computations.
Apache Ignite	server nodes also known data nodes.client nodes connection points applications services distributed database cluster server nodes.client nodes usually embedded application code written java c c special libraries developed.on top distributed foundation apache ignite supports interfaces including jcachecompliant keyvalue apis ansi sql joins acid transactions well mapreduce like computations.ignite provides odbc jdbc rest drivers way work database programming languages tools.drivers utilize either client nodes lowlevel socket connections internally order communicate cluster.partitioning replication ignite database organizes data form keyvalue pairs distributed caches cache notion used historical reasons initially database supported memory tier.generally cache represents one entity type employee organization.every cache split fixed set partitions evenly distributed among cluster nodes using rendezvous hashing algorithm.
Apache Ignite	always one primary zero backup copies partition.number copies configured replication factor parameter.full replication mode configured every cluster node store partitions copy.partitions rebalanced automatically node added removed cluster order achieve even data distribution spread workload.the keyvalue pairs kept partitions.apache ignite maps pair partition taking keys value passing special hash function.
Apache Ignite	memory architecture memory architecture apache ignite consists two storage tiers called durable memory.internally uses paging memory space management data reference similar virtual memory systems like unix.however one significant difference durable virtual memory architectures former always keeps whole data set indexes disk assuming disk tier enabled virtual memory uses disk runs ram swapping purposes only.the first tier memory architecture memory tier keeps data indexes ram java heap socalled offheap regions.regions preallocated managed database prevents java heap utilization storage needs result helping avoid long garbage collection pauses.regions split pages fixed size store data indexes system metadata.apache ignite fully operational memory tier always possible use second tier disk tier sake durability.
Apache Ignite	database comes native persistence plus use rdbms nosql hadoop databases disk tier.native persistence apache ignite native persistence distributed strongly consistent disk store always holds superset data indexes disk.memory tier cache much data depending capacity.example entries memory tier fit stored disk cached ram.persistence uses writeahead logging wal technique keeping immediate data modifications disk.background store runs checkpointing process purpose copy dirty pages memory tier partition files.
Apache Ignite	dirty page page modified memory modification recorded wal written respective partition file.checkpointing allows removing outdated wal segments time reduces cluster restart time replaying part wal applied partition files.thirdparty persistence native persistence became available starting version .. apache ignite supported thirdparty databases disk tier.apache ignite configured inmemory tier top rdbms nosql hadoop databases speeding latter.however limitations comparison native persistence.instance sql queries executed data ram thus requiring preload data set disk memory beforehand.
Apache Ignite	swap space using pure memory storage possible data size exceed physical ram size leading outofmemory errors oomes.avoid ideal approach would enable ignite native persistence use thirdparty persistence.however want use native thirdparty persistence enable swapping case ignite inmemory data moved swap space located disk.note ignite provide implementation swap space.instead takes advantage swapping functionality provided operating system os.
Apache Ignite	swap space enabled ignites stores data memory mapped files mmf whose content swapped disk os depending current ram consumption consistency apache ignite strongly consistent platform implements twophase commit protocol.consistency guarantees met memory disk tiers.transactions apache ignite acidcompliant span multiple cluster nodes caches.database supports pessimistic optimistic concurrency modes deadlockfree transactions deadlock detection techniques.in scenarios transactional guarantees optional apache ignite allows executing queries atomic mode provides better performance.distributed sql apache ignite accessed using sql apis exposed via jdbc odbc drivers native libraries developed java c c programming languages.
Apache Ignite	data manipulation data definition languages syntax complies ansi specification.being distributed database apache ignite supports distributed collocated noncollocated joins.data collocated joins executed local data cluster nodes avoiding data movement across network.noncollocated joins might move data sets around network order prepare consistent result set.machine learning apache ignite provides machine learning training inference functionality well data preprocessing model quality estimation.natively supports classical training algorithms linear regression decision trees random forest gradient boosting svm kmeans others.
Nuclear safety and security	addition apache ignite deep integration tensorflow.integrations allows train neural networks data stored apache ignite singlenode distributed manner.the key idea apache ignite machine learning toolkit ability perform distributed training inference instantly without massive data transmissions.based mapreduce approach resilient node failures data rebalances allows avoid data transfers speed preprocessing model training.referencesiaea defines nuclear security prevention detection response theft sabotage unauthorized access illegal transfer malicious acts involving nuclear materials radioactive substances associated facilities.this covers nuclear power plants nuclear facilities transportation nuclear materials use storage nuclear materials medical power industry military uses.the nuclear power industry improved safety performance reactors proposed new safer reactor designs.however perfect safety cannot guaranteed.potential sources problems include human errors external events greater impact anticipated designers reactors fukushima japan anticipate tsunami generated earthquake would disable backup systems supposed stabilize reactor earthquake.catastrophic scenarios involving terrorist attacks insider sabotage cyberattacks also conceivable.nuclear weapon safety well safety military research involving nuclear materials generally handled agencies different oversee civilian safety various reasons including secrecy.ongoing concerns terrorist groups acquiring nuclear bombmaking material.overview nuclear processes safety issues nuclear safety considerations occur number situations includingnuclear fission power used nuclear power stations nuclear submarines ships.nuclear weaponsfissionable fuels uranium plutonium extraction storage useradioactive materials used medical diagnostic research purposes batteries space projectsnuclear waste radioactive waste residue nuclear materialsnuclear fusion power technology longterm developmentunplanned entry nuclear materials biosphere food chain living plants animals humans breathed ingestedcontinuity uranium supplieswith exception thermonuclear weapons experimental fusion research safety issues specific nuclear power stems need limit biological uptake committed dose ingestion inhalation radioactive materials external radiation dose due radioactive contamination.nuclear safety therefore covers minimum extraction transportation storage processing disposal fissionable materialssafety nuclear power generatorscontrol safe management nuclear weapons nuclear material capable use weapon radioactive materialssafe handling accountability use industrial medical research contextsdisposal nuclear wastelimitations exposure radiation responsible agencies international internationally international atomic energy agency works member states multiple partners worldwide promote safe secure peaceful nuclear technologies.
Nuclear safety and security	scientists say japanese nuclear accidents revealed nuclear industry lacks sufficient oversight leading renewed calls redefine mandate iaea better police nuclear power plants worldwide.the iaea convention nuclear safety adopted vienna june entered force october .objectives convention achieve maintain high level nuclear safety worldwide establish maintain effective defences nuclear installations potential radiological hazards prevent accidents radiological consequences.the convention drawn aftermath three mile island chernobyl accidents series expert level meetings result considerable work states including national regulatory nuclear safety authorities international atomic energy agency serves secretariat convention.the obligations contracting parties based large extent application safety principles nuclear installations contained iaea document safety fundamentals ‘the safety nuclear installations’ iaea safety series no.published .obligations cover legislative regulatory framework regulatory body technical safety obligations related instance siting design construction operation availability adequate financial human resources assessment verification safety quality assurance emergency preparedness.the convention amended vienna declaration nuclear safety.resulted following principles.
Nuclear safety and security	new nuclear power plants designed sited constructed consistent objective preventing accidents commissioning operation accident occur mitigating possible releases radionuclides causing longterm site contamination avoiding early radioactive releases radioactive releases large enough require longterm protective measures actions.. comprehensive systematic safety assessments carried periodically regularly existing installations throughout lifetime order identify safety improvements oriented meet objective.reasonably practicable achievable safety improvements implemented timely manner.. national requirements regulations addressing objective throughout lifetime nuclear power plants take account relevant iaea safety standards appropriate good practices identified inter alia review meetings cns.there several problems iaea says najmedin meshkati university southern california writing recommends safety standards member states required comply promotes nuclear energy also monitors nuclear use sole global organization overseeing nuclear energy industry yet also weighed checking compliance nuclear nonproliferation treaty npt.national many nations utilizing nuclear power specialist institutions overseeing regulating nuclear safety.civilian nuclear safety u.s. regulated nuclear regulatory commission nrc.however critics nuclear industry complain regulatory bodies intertwined industries effective.
Nuclear safety and security	book doomsday machine example offers series examples national regulators put regulating waving pun waiving argue japan example regulators regulated long friends working together offset doubts public brought horror nuclear bombs.examples offered includein china kang rixin former general manager stateowned china national nuclear corporation sentenced life jail accepting bribes abuses verdict raising questions quality work safety trustworthiness chinas nuclear reactors.in india nuclear regulator reports national atomic energy commission champions building nuclear power plants chairman atomic energy regulatory board s. s. bajaj previously senior executive nuclear power corporation india company helping regulate.in japan regulator reports ministry economy trade industry overtly seeks promote nuclear industry ministry posts top jobs nuclear business passed among small circle experts.the book argues nuclear safety compromised suspicion eisaku sato formerly governor fukushima province infamous nuclear reactor complex put regulators “theyre birds feather”.the safety nuclear plants materials controlled u.s. government research weapons production powering naval vessels governed nrc.uk nuclear safety regulated office nuclear regulation onr defence nuclear safety regulator dnsr.australian radiation protection nuclear safety agency arpansa federal government body monitors identifies solar radiation nuclear radiation risks australia.main body dealing ionizing nonionizing radiation publishes material regarding radiation protection.other agencies includeautorité de sûreté nucléairecanadian nuclear safety commissionradiological protection institute irelandfederal atomic energy agency russiakernfysische dienst nlpakistan nuclear regulatory authoritybundesamt für strahlenschutz deatomic energy regulatory board india nuclear power plant safety security complexity nuclear power plants sophisticated complex energy systems ever designed.
Nuclear safety and security	complex system matter well designed engineered cannot deemed failureproof.veteran journalist author stephanie cooke arguedthe reactors enormously complex machines incalculable number things could go wrong.happened three mile island another fault line nuclear world exposed.one malfunction led another series others core reactor began melt even worlds highly trained nuclear engineers know respond.accident revealed serious deficiencies system meant protect public health safety.the three mile island accident inspired perrows book normal accidents nuclear accident occurs resulting unanticipated interaction multiple failures complex system.
Nuclear safety and security	tmi example normal accident unexpected incomprehensible uncontrollable unavoidable.perrow concluded failure three mile island consequence systems immense complexity.modern highrisk systems realized prone failures however well managed.inevitable would eventually suffer termed normal accident.therefore suggested might better contemplate radical redesign possible abandon technology entirely.a fundamental issue contributing nuclear power systems complexity extremely long lifetime.timeframe start construction commercial nuclear power station safe disposal last radioactive waste may years.
Nuclear safety and security	failure modes nuclear power plants concerns combination human mechanical error nuclear facility could result significant harm people environmentoperating nuclear reactors contain large amounts radioactive fission products dispersed pose direct radiation hazard contaminate soil vegetation ingested humans animals.human exposure high enough levels cause shortterm illness death longerterm death cancer diseases.it impossible commercial nuclear reactor explode like nuclear bomb since fuel never sufficiently enriched occur.nuclear reactors fail variety ways.instability nuclear material generate unexpected behavior may result uncontrolled power excursion.normally cooling system reactor designed able handle excess heat causes however reactor also experience lossofcoolant accident fuel may melt cause vessel contained overheat melt.event called nuclear meltdown.after shutting time reactor still needs external energy power cooling systems.
Nuclear safety and security	normally energy provided power grid plant connected emergency diesel generators.failure provide power cooling systems happened fukushima cause serious accidents.nuclear safety rules united states adequately weigh risk single event would knock electricity grid emergency generators quake tsunami recently japan nuclear regulatory commission officials said june .as safeguard mechanical failure many nuclear plants designed shut automatically two days continuous unattended operation.vulnerability nuclear plants attack nuclear reactors become preferred targets military conflict past three decades repeatedly attacked military air strikes occupations invasions campaignsin september iran bombed al tuwaitha nuclear complex iraq operation scorch sword.in june israeli air strike completely destroyed iraqs osirak nuclear research facility operation opera.between iraq bombed irans bushehr nuclear plant six times.on january umkhonto sizwe armed wing anc attacked south africas koeberg nuclear power plant still construction.in u.s. bombed three nuclear reactors enrichment pilot facility iraq.in iraq launched scud missiles israels dimona nuclear power plantin september israel bombed syrian reactor construction.in u.s. plants surrounded double row tall fences electronically monitored.plant grounds patrolled sizeable force armed guards.canada reactors onsite armed response force includes lightarmored vehicles patrol plants daily.
Nuclear safety and security	nrcs design basis threat criterion plants secret size attacking force plants able protect unknown.however scram make emergency shutdown plant takes fewer seconds unimpeded restart takes hours severely hampering terrorist force goal release radioactivity.attack air issue highlighted since september attacks u.s. however three hijackers took control domestic passenger flight along east coast u.s. threatened crash plane u.s. nuclear weapons plant oak ridge tennessee.plane got close feet site hijackers’ demands met.the important barrier release radioactivity event aircraft strike nuclear power plant containment building missile shield.former nrc chairman dale klein said nuclear power plants inherently robust structures studies show provide adequate protection hypothetical attack airplane.nrc also taken actions require nuclear power plant operators able manage large fires explosions—no matter caused them.in addition supporters point large studies carried u.s. electric power research institute tested robustness reactor waste fuel storage found able sustain terrorist attack comparable september terrorist attacks u.s. spent fuel usually housed inside plants protected zone spent nuclear fuel shipping cask stealing use dirty bomb would extremely difficult.
Nuclear safety and security	exposure intense radiation would almost certainly quickly incapacitate kill anyone attempts so.threat terrorist attacks nuclear power plants considered targets terrorist attacks.even construction first nuclear power plants issue advised security bodies.concrete threats attack nuclear power plants terrorists criminals documented several states.older nuclear power plants built without special protection air accidents germany later nuclear power plants built massive concrete buildings partially protected air accidents.
Nuclear safety and security	designed impact combat aircraft speed km h. assumed basis assessment impact aircraft type phantom ii mass tonnes speed s.the danger arising terrorist caused large aircraft crash nuclear power plant currently discussed.terrorist attack could catastrophic consequences.example german government confirmed nuclear power plant biblis would completely protected attack military aircraft.following terrorist attacks brussels several nuclear power plants partially evacuated.time became known terrorists spied nuclear power plants several employees access privileges withdrawn.moreover nuclear terrorism instance socalled dirty bomb poses considerable potential hazard.
Nuclear safety and security	plant location many countries plants often located coast order provide ready source cooling water essential service water system.consequence design needs take risk flooding tsunamis account.world energy council wec argues disaster risks changing increasing likelihood disasters earthquakes cyclones hurricanes typhoons flooding.high temperatures low precipitation levels severe droughts may lead fresh water shortages.failure calculate risk flooding correctly lead level event international nuclear event scale blayais nuclear power plant flood flooding caused tōhoku earthquake tsunami lead fukushima nuclear accidents.the design plants located seismically active zones also requires risk earthquakes tsunamis taken account.
Nuclear safety and security	japan india china usa among countries plants earthquakeprone regions.damage caused japans kashiwazakikariwa nuclear power plant chūetsu offshore earthquake underlined concerns expressed experts japan prior fukushima accidents warned genpatsushinsai dominoeffect nuclear power plant earthquake disaster.safeguarding critical infrastructure like nuclear power plants requirement necessary chemical facilities operating nuclear reactors many utility facilities.united states nuclear regulatory commission nrc developed mandates regarding enhanced security nuclear power plants.primary among changes security perimeter screening employees vendors visitors accessed site.many facilities recognize vulnerabilities licensed securitycontracting firms arisen.
Nuclear safety and security	multiple reactors fukushima nuclear disaster illustrated dangers building multiple nuclear reactor units close one another.closeness reactors plant director masao yoshida put position trying cope simultaneously core meltdowns three reactors exposed fuel pools three units.nuclear safety systems three primary objectives nuclear safety systems defined nuclear regulatory commission shut reactor maintain shutdown condition prevent release radioactive material events accidents.objectives accomplished using variety equipment part different systems performs specific functions.routine emissions radioactive materials everyday routine operations emissions radioactive materials nuclear plants released outside plants although quite slight amounts.the daily emissions go air water soil.nrc says nuclear power plants sometimes release radioactive gases liquids environment controlled monitored conditions ensure pose danger public environment routine emissions normal operation nuclear power plant never lethal.according united nations unscear regular nuclear power plant operation including nuclear fuel cycle amounts .
Nuclear safety and security	millisieverts msv annually average public radiation exposure legacy chernobyl disaster .msva global average report natural radiation exposure averages .msv annually although frequently varying depending individuals location msv.japanese public perception nuclear power safety march prime minister yoshihiko noda said japanese government shared blame fukushima disaster saying officials blinded image countrys technological infallibility steeped safety myth.japan accused authors journalist yoichi funabashi aversion facing potential threat nuclear emergencies.according national program develop robots use nuclear emergencies terminated midstream smacked much underlying danger.
Nuclear safety and security	though japan major power robotics none send fukushima disaster.mentions japans nuclear safety commission stipulated safety guidelines lightwater nuclear facilities potential extended loss power need considered.however kind extended loss power cooling pumps caused fukushima meltdown.in countries uk nuclear plants claimed absolutely safe.instead claimed major accident likelihood occurrence lower example .year.incidents fukushima daiichi nuclear disaster could avoided stricter regulations nuclear power.tepco company operated fukushima plant admitted falsifying reports occasions .
Nuclear safety and security	tepco faced fines this.instead fired four top executives.three four later went take jobs companies business tepco.uranium supplies nuclear fuel strategic resource whose continuous supply needs secured prevent plant outages.iaea recommends least two suppliers ensure supply disruptions result political events monopolistic pressure.
Nuclear safety and security	worldwide uranium supplies well diversified dozens suppliers various countries small amounts fuel required make diversification much easier case largevolume fossil fuel supplies required energy sector.example ukraine faced challenge result conflict russia continued supply fuel used leverage political pressure.ukraine obtained supplies russia half sweden number framework contracts countries.hazards nuclear material currently total tonnes highlevel nuclear waste stored usa.nuclear waste approximately uranium .
Nuclear safety and security	plutonium .actinides .fission products..waste consists longlived isotopes se zr te pd sn cs.
Nuclear safety and security	shorter lived isotopes including sr sr ru sn cs cs pm constitute .one year decreasing .years.remaining .–.consists nonradioactive isotopes.
Nuclear safety and security	technical challenges preferable lock away longlived fission products challenge exaggerated.one tonne waste described measurable radioactivity approximately tbq equal natural radioactivity one km earths crust buried would add parts per trillion total radioactivity.the difference shortlived highlevel nuclear waste longlived lowlevel waste illustrated following example.stated one mole release x decays period equal one halflife.decays release kev whilst decays release kev energy.gm would therefore release gigajoules eight days beginning initial rate ebq releasing kilowatts last radioactive decay occurring inside two years.
Nuclear safety and security	contrast gm would therefore release gigajoules .million years beginning initial rate mbq releasing microwatts radioactivity decreasing less years.one tonne nuclear waste also reduces co emission million tonnes.radionuclides may highly radioactive longlived cannot both.one mole grams undergoes number decays x .million years one mole grams days.
Nuclear safety and security	therefore highly radioactive disappears quickly whilst releases low level radiation long time.two longlived fission products technetium halflife years iodine halflife .million years somewhat greater concern greater chance entering biosphere.transuranic elements spent fuel neptunium halflife two million years plutonium halflife years.also remain environment long periods.
Nuclear safety and security	complete solution problem actinides need lowcarbon energy may integral fast reactor.one tonne nuclear waste complete burn ifr reactor prevented million tonnes co entering atmosphere.otherwise waste storage usually necessitates treatment followed longterm management strategy involving permanent storage disposal transformation waste nontoxic form.governments around world considering range waste management disposal options usually involving deepgeologic placement although limited progress toward implementing longterm waste management solutions.partly timeframes question dealing radioactive waste range millions years according studies based effect estimated radiation doses.since fraction radioisotopes atoms decaying per unit time inversely proportional halflife relative radioactivity quantity buried human radioactive waste would diminish time compared natural radioisotopes decay chain trillion tons thorium trillion tons uranium relatively trace concentrations parts per million crusts ton mass.instance timeframe thousands years active short halflife radioisotopes decayed burying u.s. nuclear waste would increase radioactivity top feet rock soil united states million km ≈ part million cumulative amount natural radioisotopes volume although vicinity site would far higher concentration artificial radioisotopes underground average.
Nuclear safety and security	safety culture human errors one relatively prevalent notion discussions nuclear safety safety culture.international nuclear safety advisory group defines term “the personal dedication accountability individuals engaged activity bearing safety nuclear power plants”.goal “to design systems use human capabilities appropriate ways protect systems human frailties protect humans hazards associated system”.at time evidence operational practices easy change.operators almost never follow instructions written procedures exactly “the violation rules appears quite rational given actual workload timing constraints operators must job”.many attempts improve nuclear safety culture “were compensated people adapting change unpredicted way”.according arevas southeast asia oceania director selena ng japans fukushima nuclear disaster huge wakeup call nuclear industry hasnt always sufficiently transparent safety issues.
Nuclear safety and security	said sort complacency fukushima dont think afford complacency now.an assessment conducted commissariat à l’énergie atomique cea france concluded amount technical innovation eliminate risk humaninduced errors associated operation nuclear power plants.two types mistakes deemed serious errors committed field operations maintenance testing cause accident human errors made small accidents cascade complete failure.according mycle schneider reactor safety depends culture security including quality maintenance training competence operator workforce rigour regulatory oversight.betterdesigned newer reactor always safer one older reactors necessarily dangerous newer ones.three mile island accident united states occurred reactor started operation three months earlier chernobyl disaster occurred two years operation.serious loss coolant occurred french civaux reactor less five months startup.however safe plant designed operated humans prone errors.
Nuclear safety and security	laurent stricker nuclear engineer chairman world association nuclear operators says operators must guard complacency avoid overconfidence.experts say largest single internal factor determining safety plant culture security among regulators operators workforce — creating culture easy.investigative journalist eric schlosser author command control discovered least significant accidents incidents involving nuclear weapons recorded united states .experts believe nuclear weapons lost cold war.risks routine health risks greenhouse gas emissions nuclear fission power small relative associated coal several catastrophic risksthe extreme danger radioactive material power plants nuclear technology well known us government prompted industrys urging enact provisions protect nuclear industry bearing full burden inherently risky nuclear operations.priceanderson act limits industrys liability case accidents nuclear waste policy act charges federal government responsibility permanently storing nuclear waste.population density one critical lens risks assessed says laurent stricker nuclear engineer chairman world association nuclear operatorsthe kanupp plant karachi pakistan people — .
Nuclear safety and security	million — living within kilometres nuclear plant although one relatively small reactor output megawatts.next league however much larger plants — taiwans megawatt kuosheng plant .million people within kilometre radius megawatt chin plant .million zones include capital city taipei.people living within kilometre radius fukushima daiichi nuclear power plant forced advised evacuate area.
Nuclear safety and security	generally analysis nature columbia university new york shows nuclear plants populations larger million within km radius six plants populations larger million within radius.black swan events highly unlikely occurrences big repercussions.despite planning nuclear power always vulnerable black swan eventsa rare event – especially one never occurred – difficult foresee expensive plan easy discount statistics.something supposed happen every years mean happen tomorrow.typical year life plant assumptions also change september august hurricane katrina struck march fukushima.the list potential black swan events damningly diversenuclear reactors spentfuel pools could targets terrorists piloting hijacked planes.reactors may situated downstream dams ever burst could unleash massive floods.
Nuclear safety and security	reactors located close faults shorelines dangerous scenario like emerged three mile island fukushima – catastrophic coolant failure overheating melting radioactive fuel rods release radioactive material.the ap estimated core damage frequency .x − per plant per year.evolutionary power reactor epr estimated core damage frequency x − per plant per year.general electric published recalculated estimated core damage frequencies per year per plant nuclear power plant designsbwr – x −bwr – x −abwr – x −esbwr – x − beyond design basis events fukushima nuclear accident caused beyond design basis event tsunami associated earthquakes powerful plant designed accommodate accident directly due tsunami overflowing toolow seawall.since possibility unforeseen beyond design basis events major concern plant operators.
Nuclear safety and security	transparency ethics according journalist stephanie cooke difficult know really goes inside nuclear power plants industry shrouded secrecy.corporations governments control information made available public.cooke says information made available often couched jargon incomprehensible prose.kennette benedict said nuclear technology plant operations continue lack transparency relatively closed public viewdespite victories like creation atomic energy commission later nuclear regular commission secrecy began manhattan project tended permeate civilian nuclear program well military defense programs.in soviet officials held reporting chernobyl disaster several days.operators fukushima plant tokyo electric power co also criticised quickly disclosing information releases radioactivity plant.russian president dmitry medvedev said must greater transparency nuclear emergencies.historically many scientists engineers made decisions behalf potentially affected populations whether particular level risk uncertainty acceptable them.
Nuclear safety and security	many nuclear engineers scientists made decisions even good reasons relating long term energy availability consider without informed consent wrong nuclear power safety nuclear technologies based fundamentally morality rather purely technical economic business considerations.nonnuclear futures case ethical energy strategy book amory b. lovins john h. price.main theme book important parts nuclear power debate technical disputes relate personal values legitimate province every citizen whether technically trained not.nuclear radiation accidents nuclear industry excellent safety record deaths per megawatt hour lowest major energy sources.according zia mian alexander glaser past six decades shown nuclear technology tolerate error.nuclear power perhaps primary example called ‘highrisk technologies’ ‘catastrophic potential’ “no matter effective conventional safety devices form accident inevitable accidents ‘normal’ consequence system.” short escape system failures.whatever position one takes nuclear power debate possibility catastrophic accidents consequent economic costs must considered nuclear policy regulations framed.
Nuclear safety and security	accident liability protection kristin shraderfrechette said reactors safe nuclear industries would demand governmentguaranteed accidentliability protection condition generating electricity.private insurance company even consortium insurance companies would shoulder fearsome liabilities arising severe nuclear accidents.hanford site hanford site mostly decommissioned nuclear production complex columbia river u.s. state washington operated united states federal government.plutonium manufactured site used first nuclear bomb tested trinity site fat man bomb detonated nagasaki japan.cold war project expanded include nine nuclear reactors five large plutonium processing complexes produced plutonium weapons u.s. nuclear arsenal.
Nuclear safety and security	many early safety procedures waste disposal practices inadequate government documents since confirmed hanfords operations released significant amounts radioactive materials air columbia river still threatens health residents ecosystems.weapons production reactors decommissioned end cold war decades manufacturing left behind million us gallons highlevel radioactive waste additional million cubic feet solid radioactive waste square miles km contaminated groundwater beneath site occasional discoveries undocumented contaminations slow pace raise cost cleanup.hanford site represents twothirds nations highlevel radioactive waste volume.today hanford contaminated nuclear site united states focus nations largest environmental cleanup.chernobyl disaster chernobyl disaster nuclear accident occurred april chernobyl nuclear power plant ukraine.
Nuclear safety and security	explosion fire released large quantities radioactive contamination atmosphere spread much western ussr europe.considered worst nuclear power plant accident history one two classified level event international nuclear event scale fukushima daiichi nuclear disaster.battle contain contamination avert greater catastrophe ultimately involved workers cost estimated billion rubles crippling soviet economy.the accident raised concerns safety nuclear power industry slowing expansion number years.unscear conducted years detailed scientific epidemiological research effects chernobyl accident.apart direct deaths accident unscear predicted additional cancer deaths related accident would appear among persons receiving significant exposures liquidators working – evacuees residents contaminated areas.russia ukraine belarus burdened continuing substantial decontamination health care costs chernobyl disaster.eleven russias reactors rbmk type similar one chernobyl nuclear power plant.
Nuclear safety and security	rbmk reactors originally shut instead given life extensions uprated output .critics say reactors inherently unsafe design cannot improved upgrades modernization reactor parts impossible replace.russian environmental groups say lifetime extensions violate russian law projects undergone environmental assessments.fukushima accidents despite assurances major nuclear accident scale chernobyl disaster happened japan one worlds industrially advanced countries.nuclear safety commission chairman haruki madarame told parliamentary inquiry february japans atomic safety rules inferior global standards left country unprepared fukushima nuclear disaster last march.
Nuclear safety and security	flaws lax enforcement safety rules governing japanese nuclear power companies included insufficient protection tsunamis.a report economist said reactors fukushima old design.risks faced well analysed.operating company poorly regulated know going on.operators made mistakes.representatives safety inspectorate fled.
Nuclear safety and security	equipment failed.establishment repeatedly played risks suppressed information movement radioactive plume people evacuated lightly heavily contaminated places.the designers fukushima nuclear power plant reactors anticipate tsunami generated earthquake would disable backup systems supposed stabilize reactor earthquake.nuclear reactors inherently complex tightly coupled systems rare emergency situations cascading interactions unfold rapidly way human operators unable predict master them.lacking electricity pump water needed cool atomic core engineers vented radioactive steam atmosphere release pressure leading series explosions blew concrete walls around reactors.radiation readings spiked around fukushima disaster widened forcing evacuation people.rise radiation levels outskirts tokyo population million miles kilometers south.backup diesel generators might averted disaster positioned basement quickly overwhelmed waves.
Nuclear safety and security	cascade events fukushima predicted report published u.s. several decades agothe report u.s. nuclear regulatory commission independent agency responsible safety countrys power plants identified earthquakeinduced diesel generator failure power outage leading failure cooling systems one “most likely causes” nuclear accidents external event.the report cited statement japans nuclear industrial safety agency seems adequate measures address risk taken tepco.katsuhiko ishibashi seismology professor kobe university said japans history nuclear accidents stems overconfidence plant engineering.resigned government panel nuclear reactor safety review process rigged “unscientific”.according international atomic energy agency japan underestimated danger tsunamis failed prepare adequate backup systems fukushima daiichi nuclear plant.repeated widely held criticism japan collusive ties regulators industry led weak oversight failure ensure adequate safety levels plant.iaea also said fukushima disaster exposed lack adequate backup systems plant.
Nuclear safety and security	power completely lost critical functions like cooling system shut down.three reactors quickly overheated causing meltdowns eventually led explosions hurled large amounts radioactive material air.louise fréchette trevor findlay said effort needed ensure nuclear safety improve responses accidentsthe multiple reactor crises japans fukushima nuclear power plant reinforce need strengthening global instruments ensure nuclear safety worldwide.fact country operating nuclear power reactors decades prove alarmingly improvisational response unwilling reveal facts even people much less international atomic energy agency reminder nuclear safety constant workinprogress.david lochbaum chief nuclear safety officer union concerned scientists repeatedly questioned safety fukushima plants general electric mark reactor design used almost quarter united states nuclear fleet.a report japanese government iaea says nuclear fuel three reactors probably melted inner containment vessels core.report says inadequate basic reactor design — mark model developed general electric — included venting system containment vessels location spent fuel cooling pools high buildings resulted leaks radioactive water hampered repair work.following fukushima emergency european union decided reactors across member nations undergo safety tests.according ubs ag fukushima nuclear accidents likely hurt nuclear power industrys credibility chernobyl disaster accident former soviet union years ago affected one reactor totalitarian state safety culture ubs analysts including per lekander stephen oldfield wrote report today.fukushima four reactors control weeks – casting doubt whether even advanced economy master nuclear safety.the fukushima accident exposed troubling nuclear safety issuesdespite resources poured analyzing crustal movements expert committees determine earthquake risk instance researchers never considered possibility magnitude earthquake followed massive tsunami.
Nuclear safety and security	failure multiple safety features nuclear power plants raised questions nations engineering prowess.government flipflopping acceptable levels radiation exposure confused public health professionals provided little guidance.facing dearth reliable information radiation levels citizens armed dosimeters pooled data together produced radiological contamination maps far detailed anything government official scientific sources ever provided.as january questions also linger extent damage fukushima plant caused earthquake even tsunami hit.evidence serious quake damage plant would cast new doubt safety reactors quakeprone japan.two government advisers said japans safety review nuclear reactors fukushima disaster based faulty criteria many people involved conflicts interest.hiromitsu ino professor emeritus university tokyo saysthe whole process undertaken exactly used previous fukushima daiichi accident even though accident showed guidelines categories insufficient.in march prime minister yoshihiko noda acknowledged japanese government shared blame fukushima disaster saying officials blinded false belief countrys technological infallibility steeped safety myth.
Nuclear safety and security	accidents serious nuclear radiation accidents include chalk river accidents mayak disaster windscale fire sl accident soviet submarine k accident three mile island accident church rock uranium mill spill soviet submarine k accident therac accidents goiânia accident zaragoza radiotherapy accident costa rica radiotherapy accident tokaimura nuclear accident sellafield thorp leak flerus ire cobalt spill .health impacts four hundred thirtyseven nuclear power stations presently operation unfortunately five major nuclear accidents occurred past.accidents occurred kyshtym windscale three mile island chernobyl fukushima .report lancet says effects accidents individuals societies diverse enduringaccumulated evidence radiation health effects atomic bomb survivors radiationexposed people formed basis national international regulations radiation protection.however past experiences suggest common issues necessarily physical health problems directly attributable radiation exposure rather psychological social effects.
Nuclear safety and security	additionally evacuation longterm displacement created severe healthcare problems vulnerable people hospital inpatients elderly people.in spite accidents like studies shown nuclear deaths mostly uranium mining nuclear energy generated far fewer deaths high pollution levels result use conventional fossil fuels.however nuclear power industry relies uranium mining hazardous industry many accidents fatalities.journalist stephanie cooke says useful make comparisons terms number deaths way people live afterwards also relevant case japanese nuclear accidentsyou people japan right facing either returning homes forever return homes living contaminated area basically ever... affects millions people affects land affects atmosphere ... affecting future generations ... dont think great big massive plants spew pollution air good.dont think really helpful make comparisons terms number deaths.the fukushima accident forced residents evacuate neighborhoods around plant.a survey iitate fukushima local government obtained responses people evacuated village lies within emergency evacuation zone around crippled fukushima daiichi plant.shows many residents experiencing growing frustration instability due nuclear crisis inability return lives living disaster.sixty percent respondents stated health health families deteriorated evacuating .
Nuclear safety and security	percent reported feeling irritated compared disaster.summarizing responses questions related evacuees current family status onethird surveyed families live apart children .percent live away family members including elderly parents lived disaster.survey also showed .percent evacuees suffered salary cuts percent since outbreak nuclear disaster.total .
Nuclear safety and security	percent reported lack sleep .percent reported smoking drinking evacuated.chemical components radioactive waste may lead cancer.for example iodine released along radioactive waste chernobyl disaster fukushima disasters occurred.concentrated leafy vegetation absorption soil.also stays animals’ milk animals eat vegetation.iodine enters human body migrates thyroid gland neck cause thyroid cancer.other elements nuclear waste lead cancer well.
Nuclear safety and security	example strontium causes breast cancer leukemia plutonium causes liver cancer.improvements nuclear fission technologies redesigns fuel pellets cladding undertaken improve safety existing power plants.newer reactor designs intended provide increased safety developed time.designs include incorporate passive safety small modular reactors.reactor designs intended inspire trust may unintended effect creating distrust older reactors lack touted safety features.the next nuclear plants built likely generation iii iii designs already operation japan.generation iv reactors would even greater improvements safety.
Nuclear safety and security	new designs expected passively safe nearly perhaps even inherently safe pbmr designs.some improvements made designs three sets emergency diesel generators associated emergency core cooling systems rather one pair quench tanks large coolantfilled tanks core open automatically double containment one containment building inside another etc.approximately reactors switzerland prior reactors japan fukushima accident incorporate filtered containment venting systems onto containment structure designed relieve containment pressure accident releasing gases environment retaining fission products filter structures.however safety risks may greatest nuclear systems newest operators less experience them.nuclear engineer david lochbaum explained almost serious nuclear accidents occurred time recent technology.argues problem new reactors accidents twofold scenarios arise impossible plan simulations humans make mistakes.one director u.s. research laboratory put fabrication construction operation maintenance new reactors face steep learning curve advanced technologies heightened risk accidents mistakes.technology may proven people not.
Nuclear safety and security	developing countries concerns developing countries rushing join socalled nuclear renaissance without necessary infrastructure personnel regulatory frameworks safety culture.countries nuclear aspirations like nigeria kenya bangladesh venezuela significant industrial experience require least decade preparation even breaking ground reactor site.the speed nuclear construction program china raised safety concerns.challenge government nuclear companies keep eye growing army contractors subcontractors may tempted cut corners.china asked international assistance training nuclear power plant inspectors.nuclear security terrorist attacks nuclear power plants civilian research reactors certain naval fuel facilities uranium enrichment plants fuel fabrication plants vulnerable attacks could lead widespread radioactive contamination.
Nuclear safety and security	attack threat several general types commandolike groundbased attacks equipment disabled could lead reactor core meltdown widespread dispersal radioactivity external attacks aircraft crash reactor complex cyber attacks.the united states commission said nuclear power plants potential targets originally considered september attacks.terrorist groups could sufficiently damage safety systems cause core meltdown nuclear power plant andor sufficiently damage spent fuel pools attack could lead widespread radioactive contamination.federation american scientists said nuclear power use expand significantly nuclear facilities made extremely safe attacks could release massive quantities radioactivity community.new reactor designs features passive safety may help.united states nrc carries force force fof exercises nuclear power plant npp sites least every three years.nuclear reactors become preferred targets military conflict past three decades repeatedly attacked military air strikes occupations invasions campaigns.
Nuclear safety and security	various acts civil disobedience since peace group plowshares shown nuclear weapons facilities penetrated groups actions represent extraordinary breaches security nuclear weapons plants united states.national nuclear security administration acknowledged seriousness plowshares action.nonproliferation policy experts questioned use private contractors provide security facilities manufacture store governments dangerous military material.nuclear weapons materials black market global concern concern possible detonation small crude nuclear weapon militant group major city significant loss life property.stuxnet computer worm discovered june believed created united states israel attack irans nuclear facilities.
Nuclear safety and security	nuclear fusion research nuclear fusion power developing technology still research.relies fusing rather fissioning splitting atomic nuclei using different processes compared current nuclear power plants.nuclear fusion reactions potential safer generate less radioactive waste fission.reactions appear potentially viable though technically quite difficult yet created scale could used functional power plant.fusion power theoretical experimental investigation since s.construction international thermonuclear experimental reactor facility began project run many delays budget overruns.
Nuclear safety and security	facility expected begin operations year – years initially anticipated.follow commercial nuclear fusion power station demo proposed.also suggestions power plant based upon different fusion approach inertial fusion power plant.fusion powered electricity generation initially believed readily achievable fission power been.however extreme requirements continuous reactions plasma containment led projections extended several decades.years first attempts commercial power production still believed unlikely .
Computer memory	stringent safety standards matthew bunn former us office science technology policy adviser heinonen former deputy director general iaea said need stringent nuclear safety standards propose six major areas improvementoperators must plan events beyond design basesmore stringent standards protecting nuclear facilities terrorist sabotagea stronger international emergency responseinternational reviews security safetybinding international standards safety security andinternational cooperation ensure regulatory effectiveness.coastal nuclear sites must also protected rising sea levels storm surges flooding possible eventual nuclear site islanding.see also lists nuclear disasters radioactive incidentsdeep geological repositorydesign basis accidentenvironmental impact nuclear powerinternational nuclear events scalejourney safest place earthnuclear terrorismnuclear accidents united statesnuclear criticality safetyrelapd reactor design simulation tool prevent accidents.nuclear fuel response reactor accidentsnuclear holocaustnuclear power debatenuclear power plant emergency response teamnuclear whistleblowersnuclear weaponmicro nuclear reactorpassive nuclear safetyyucca mountain nuclear waste repositorysafety code nuclear reactormaterial unaccounted references external links international atomic energy agency websitenuclear safety info resourcesnuclear safety discussion forumsthe nuclear energy option online book bernard l. cohen.emphasis risk estimates nuclear.term memory often synonymous term primary storage main memory.archaic synonym memory store.computer memory operates high speed compared storage slower less expensive higher capacity.besides storing opened programs computer memory serves disk cache write buffer improve reading writing performance.operating systems borrow ram capacity caching long needed running software.needed contents computer memory transferred storage common way memory management technique called virtual memory.modern memory implemented semiconductor memory data stored within memory cells built mos transistors components integrated circuit.
Computer memory	two main kinds semiconductor memory volatile nonvolatile.examples nonvolatile memory flash memory rom prom eprom eeprom memory.examples volatile memory dynamic randomaccess memory dram used primary storage static randomaccess memory sram used cpu cache.most semiconductor memory organized memory cells storing one bit .flash memory organization includes one bit per memory cell multilevel cell capable storing multiple bits per cell.memory cells grouped words fixed word length example bits.
Computer memory	word accessed binary address n bits making possible store n words memory.history early memory technology often permitted capacity bytes.first electronic programmable digital computer eniac using thousands vacuum tubes could perform simple calculations involving numbers ten decimal digits stored vacuum tubes.the next significant advance computer memory came acoustic delayline memory developed j. presper eckert early s. construction glass tube filled mercury plugged end quartz crystal delay lines could store bits information form sound waves propagating mercury quartz crystals acting transducers read write bits.delayline memory limited capacity thousand bits.two alternatives delay line williams tube selectron tube originated using electron beams glass tubes means storage.using cathode ray tubes fred williams invented williams tube first randomaccess computer memory.
Computer memory	williams tube able store information selectron tube selectron limited bits williams tube could store thousands less expensive.williams tube nevertheless frustratingly sensitive environmental disturbances.efforts began late find nonvolatile memory.magneticcore memory allowed recall memory power loss.developed frederick w. viehe wang late improved jay forrester jan a. rajchman early commercialised whirlwind computer .magneticcore memory dominant form memory development mos semiconductor memory s.the first semiconductor memory implemented flipflop circuit early using bipolar transistors.
Computer memory	semiconductor memory made discrete devices first shipped texas instruments united states air force .year concept solidstate memory integrated circuit ic chip proposed applications engineer bob norman fairchild semiconductor.first bipolar semiconductor memory ic chip sp introduced ibm .semiconductor memory offered improved performance magneticcore memory remain larger expensive displace magneticcore memory late s. mos memory invention metal–oxide–semiconductor fieldeffect transistor mosfet enabled practical use metal–oxide–semiconductor mos transistors memory cell storage elements.mos memory developed john schmidt fairchild semiconductor .
Computer memory	addition higher performance mos semiconductor memory cheaper consumed less power magnetic core memory.j. wood r. ball royal radar establishment proposed digital storage systems use cmos complementary mos memory cells addition mosfet power devices power supply switched crosscoupling switches delayline storage.development silicongate mos integrated circuit mos ic technology federico faggin fairchild enabled production mos memory chips.nmos memory commercialized ibm early s. mos memory overtook magnetic core memory dominant memory technology early s.the two main types volatile randomaccess memory ram static randomaccess memory sram dynamic randomaccess memory dram.bipolar sram invented robert norman fairchild semiconductor followed development mos sram john schmidt fairchild .
Computer memory	sram became alternative magneticcore memory requires six transistors bit data.commercial use sram began ibm introduced sp sram chip system model .toshiba introduced bipolar dram memory cells toscal bc electronic calculator .offered improved performance bipolar dram could compete lower price dominant magneticcore memory.mos technology basis modern dram.robert h. dennard ibm thomas j. watson research center working mos memory.
Computer memory	examining characteristics mos technology found possible build capacitors storing charge charge mos capacitor could represent bit mos transistor could control writing charge capacitor.led development singletransistor dram memory cell.dennard filed patent singletransistor dram memory cell based mos technology.led first commercial dram ic chip intel october .synchronous dynamic randomaccess memory sdram later debuted samsung kmsl chip .the term memory also often used refer nonvolatile memory including readonly memory rom modern flash memory.
Computer memory	programmable readonly memory prom invented wen tsing chow working arma division american bosch arma corporation.dawon kahng simon sze bell labs proposed floating gate mos semiconductor device could used cell reprogrammable rom led dov frohman intel inventing eprom erasable prom .eeprom electrically erasable prom developed yasuo tarui yutaka hayashi kiyoko naga electrotechnical laboratory .flash memory invented fujio masuoka toshiba early s. masuoka colleagues presented invention flash nand flash .toshiba commercialized nand flash memory .developments technology economies scale made possible socalled large memory vlm computers.
Computer memory	volatile memory volatile memory computer memory requires power maintain stored information.modern semiconductor volatile memory either static ram sram dynamic ram dram.sram retains contents long power connected simpler interfacing uses six transistors per bit.dynamic ram complicated interfacing control needing regular refresh cycles prevent losing contents uses one transistor one capacitor per bit allowing reach much higher densities much cheaper perbit costs.sram worthwhile desktop system memory dram dominates used cache memories.sram commonplace small embedded systems might need tens kilobytes less.
Computer memory	volatile memory technologies attempted compete replace sram dram include zram aram.nonvolatile memory nonvolatile memory computer memory retain stored information even powered.examples nonvolatile memory include readonly memory see rom flash memory types magnetic computer storage devices e.g.hard disk drives floppy disks magnetic tape optical discs early computer storage methods paper tape punched cards.forthcoming nonvolatile memory technologies include feram cbram pram sttram sonos rram racetrack memory nram xpoint millipede memory.semivolatile memory third category memory semivolatile.
Computer memory	term used describe memory limited nonvolatile duration power removed data ultimately lost.typical goal using semivolatile memory provide high performancedurabilityetc.associated volatile memories providing benefits true nonvolatile memory.for example nonvolatile memory types wear worn cell increased volatility otherwise continues work.data locations written frequently thus directed use worn circuits.long location updated within known retention time data stays valid.
Computer memory	retention time expires without update value copied lessworn circuit longer retention.writing first worn area allows high write rate avoiding wear notworn circuits.as second example sttram made nonvolatile building large cells cost per bit write power go write speed goes down.using small cells improves cost power speed leads semivolatile behavior.applications increased volatility managed provide many benefits nonvolatile memory example removing power forcing wakeup data lost caching readonly data discarding cached data poweroff time exceeds nonvolatile threshold.the term semivolatile also used describe semivolatile behavior constructed memory types.example volatile nonvolatile memory may combined external signal copies data volatile memory nonvolatile memory power removed without copying data lost.
Computer memory	batterybacked volatile memory external power lost known period battery continue power volatile memory power extended time battery runs data lost.management proper management memory vital computer system operate properly.modern operating systems complex systems properly manage memory.failure lead bugs slow performance worst case takeover viruses malicious software.bugs improper management memory common cause bugs including following typesin arithmetic overflow calculation results number larger allocated memory permits.
Computer memory	example signed bit integer allows numbers − .value instructed add one computer store number space.case result undesired operation changing numbers value − instead .a memory leak occurs program requests memory operating system never returns memory done it.program bug gradually require memory program fails runs out.a segmentation fault results program tries access memory permission access.generally program terminated operating system.a buffer overflow means program writes data end allocated space continues write data memory allocated purposes.
Computer memory	may result erratic program behavior including memory access errors incorrect results crash breach system security.thus basis many software vulnerabilities maliciously exploited.early computer systems early computer systems programs typically specified location write memory data put there.location physical location actual memory hardware.slow processing computers allow complex memory management systems used today.
Computer memory	also systems singletask sophisticated systems required much.this approach pitfalls.location specified incorrect cause computer write data part program.results error like unpredictable.cases incorrect data might overwrite memory used operating system.computer crackers take advantage create viruses malware.
Computer memory	virtual memory virtual memory system physical memory controlled operating system.program needs memory requests operating system.operating system decides physical location place programs code data.this offers several advantages.computer programmers longer need worry data physically stored whether users computer enough memory.also allows multiple types memory used.
Computer memory	example data stored physical ram chips data stored hard drive e.g.swapfile functioning extension cache hierarchy.drastically increases amount memory available programs.operating system place actively used data physical ram much faster hard disks.amount ram sufficient run current programs result situation computer spends time moving data ram disk back accomplishing tasks known thrashing.
Computer memory	protected memory protected memory system program given area memory use permitted go outside range.use protected memory greatly enhances reliability security computer system.without protected memory possible bug one program alter memory used another program.cause program run corrupted memory unpredictable results.operating systems memory corrupted entire computer system may crash need rebooted.times programs intentionally alter memory used programs.
Computer memory	done viruses malware take computers.may also used benignly desirable programs intended modify programs modern age generally considered bad programming practice application programs may used system development tools debuggers example insert breakpoints hooks.protected memory assigns programs areas memory.operating system detects program tried alter memory belong program terminated otherwise restricted redirected.way offending program crashes programs affected misbehavior whether accidental intentional.protected memory systems almost always include virtual memory well.see also memory geometrymemory hierarchymemory organizationprocessor registers store data normally considered memory since store one word include addressing mechanism.semiconductor memoryunits information notes references reading miller stephen w. memory storage technology montvale.
Myspace	afips pressmemory storage technology alexandria virginia.time life bookssmall ray reaches total length approximately fish centimetres endemic northeastern atlantic ocean ireland iceland south bay biscay.occurs depths metres ft. referenceslaunched august site first social network reach global audience significant influence technology pop culture music.site played critical role early growth companies like youtube created developer platform launched successes zynga rockyou photobucket among others.myspace largest social networking site world.in july myspace acquired news corporation million june surpassed yahoo google become visited website united states.generated million revenue fiscal year.peak april myspace facebook reached million unique users myspace narrowly lost newly emerging facebook terms global users.
Myspace	may facebook surpassed myspace number unique u.s. visitors.since number myspace users declined steadily despite several redesigns.sites monthly visitors dropped seven million.in june myspace employed approximately employees.june specific media group justin timberlake jointly purchased company approximately million.february announced myspace parent company purchased time inc. million.
Myspace	time inc. turn purchased meredith corporation january .november meredith spun myspace original holding company viant technology holding inc. sold viant technology llc.history – beginnings rise august several euniverse employees friendster accounts saw potential social networking features.group decided mimic popular features website.within days first version myspace ready launch implemented using coldfusion.
Myspace	complete infrastructure finance human resources technical expertise bandwidth server capacity available site.project overseen brad greenspan euniverses founder chairman ceo managed chris dewolfe myspaces starting ceo josh berman tom anderson myspaces starting president team programmers resources provided euniverse.early period june prior birth myspace jeffrey edell brought chairman parent company intermix media.the first myspace users euniverse employees.company held contests see could sign users.euniverse used million users email subscribers breathe life myspace move head pack social networking websites.
Myspace	key architect tech expert toan nguyen helped stabilize platform greenspan asked join team.cofounder cto aber whitcomb played integral role software architecture utilizing thensuperior development speed coldfusion dynamic database driven serverside languages time.despite ten times number developers friendster developed javaserver pages jsp could keep speed development myspace cfm.example users could customize background look feel pages myspace.the myspace.com domain originally owned yourz.com inc. intended use online data storage sharing site.late transitioned file storage service social networking site.

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