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1、图书馆管理系统的实现基于VB图书馆管理系统的设计与实现论文导读:就爱阅读网友为您分享以下“基于VB图书馆管理系统的设计与实现论文”的资讯,希望对您有所帮助,感谢您对92to.com的支持!附录A外文资料VirtualServersServervirtualizationisoneofthoseraretechnologiesthatsoundstoogoodtobetrue,butit’sreal.Itsearliestusewastoconsolidateunderutilizedserverhardware
2、ontoasmallernumberofmachines.Sincethoseearlydays,ithasgrownintoamultipurposesolutionthatenablesgreaterreliability,improvedmanagement,andotherbenefitsthatmakeitanall-but-indispensabletoolforenterprisedatacenter9administrators.Touseanoversimplifieddefinition,a
3、virtualservermimics,usingsoftwarealone,thebehaviorandcapabilitiesofastand-alonecomputer.Thenomenclatureofvirtualizationissimple.Thebottomofthesoftwarestackisoccupiedbyasingleinstanceofanordinaryoperatingsystemthat’sinstalleddirectlyontotheserverhardware.Abov
4、ethat,avirtualizationlayerhandlestheredirectionandemulationthatmakeupthevirtualcomputer.Thecombinationofthesetwolowerlayersisreferredtoasthehost.ThehostprovidesthefullworkingsofafamiliarPCrightdowntoitsBIOSROM,anditcanspawnasmanyindependentPCs—usingvaryingus
5、er-definedconfigurations—asyouchoose.Asarephysicalservers,avirtualPCisuselessuntilyouinstallanoperatingsystemonit.Theoperatingsystemsthatyouinstallonyourvirtualhostsarecalledguests.InstallingaguestOScanbeaseasyasbootingfromtheOS’sinstallationCD.It’sjustlikei
6、nstallinganOSonaPC,and9ingeneral,ifyouwonderhowvirtualizationwillbehave,that’stheanswer:JustlikeaPC.Infact,inanall-Windowsenvironment,it’seasytoloseyourplace:AreyoulookingatyourWindowshostOSoratoneofthefourWindowsguestOSesyoujustinstalled?Youmightgetconfused
7、,butyourguestOSesandtheirapplicationsneverdo.EachguestOSbelievesithasthewholemachinetoitself.And,inasense,itdoes.Software-basedhardwareOperatingsystemsandapplicationsrunningonvirtualserversdon’thavedirectcontroloverresourcessuchasmemory,harddrives,andnetwork
8、ports.Instead,theVMthatsitsbeneaththeOSandapplicationsinterceptsrequestsforinteractionwithhardwareandhandlesthemasitseesfit.Therealmindblowerthatturnsthistechnologyintosomethingclosetomagicistha