计算机应用基础英文版课件：4.OS

计算机应用基础FundamentalsofComputerandComputingFundamentalsofComputerandComputingChapter#1

ProblemsolvinginCSChapter#2

Datarepresentationincomputers

Chapter#3

HardwareChapter#4

OperatingsystemChapter#5

NetworkandinternetChapter#6

DatabasemanagementsystemChapter#7

ComputingasadisciplineChapter#8

AlgorithmandprogrammingOutlineWhatisoperatingsystem(OS)andwhy?DevelopmentofOSSoftwareCategoriesFunctionsofOSTypesofOSFilesystem3Whatandwhy4AnOSisaprogramwhichactsasaninterfacebetweencomputersystemusersandthecomputerhardware.Itprovidesauser-friendlyenvironmentinwhichausermayeasilydevelopandexecuteprograms.So,itcanbesaidthatanOShidesthecomplexityofhardwarefromuninterestedusers.OperatingsystemtimelineFirstgeneration:1945–1955VacuumtubesPlugboardsSecondgeneration:1955–1965TransistorsBatchsystemsThirdgeneration:1965–1980IntegratedcircuitsMultiprogrammingFourthgeneration:1980–presentLargescaleintegrationPersonalcomputersNextgeneration:???Systemsconnectedbyhigh-speednetworks?Widearearesourcemanagement?Firstgeneration:directinputRunonejobatatimeEnteritintothecomputer(mightrequirerewiring!)RunitRecordtheresultsProblem:lotsofwastedcomputertime!ComputerwasidleduringfirstandlaststepsComputerswereveryexpensive!Goal:makebetteruseofanexpensivecommodity:computertimeFirstgeneration:directinputProgramswereloadedintomemorymanuallyusingswitches,punchedcards,orpapertapes.ENIAC:codingbycableconnectionsFirstgeneration:directinputPapertapeFirstgeneration:directinputSecondgeneration:batchsystemsBringcardsto1401ReadcardsontoinputtapePutinputtapeon7094Performthecomputation,writingresultstooutputtapePutoutputtapeon1401,whichprintsoutput$END$RUN$LOADStructureofatypical2ndgenerationjob$FORTRAN$JOB,10,6610802,ETHANMILLERFORTRAN

programDatafor

programSpoolingOriginalbatchsystemsusedtapedrivesLaterbatchsystemsuseddisksforbufferingOperatorreadcardsontodiskattachedtothecomputerComputerreadjobsfromdiskComputerwrotejobresultstodiskOperatordirectedthatjobresultsbeprintedfromdiskDisksenabledsimultaneousperipheraloperationon-line(spooling)ComputeroverlappedI/OofonejobwithexecutionofanotherBetterutilizationoftheexpensiveCPUStillonlyonejobactiveatanygiventimeOperating

systemThirdgeneration:multiprogrammingMultiplejobsinmemoryProtectedfromoneanotherOperatingsystemprotectedfromeachjobaswellResources(time,hardware)splitbetweenjobsStillnotinteractiveUsersubmitsjobComputerrunsitUsergetsresultsminutes(hours,days)laterJob1Job2Job3Memory

partitionsOperatingsystemtimelineFirstgeneration:1945–1955VacuumtubesPlugboardsSecondgeneration:1955–1965TransistorsBatchsystemsThirdgeneration:1965–1980IntegratedcircuitsMultiprogrammingFourthgeneration:1980–presentLargescaleintegrationPersonalcomputersNextgeneration:???Systemsconnectedbyhigh-speednetworks?Widearearesourcemanagement?OutlineWhatisOSandwhy?DevelopmentofOSSoftwareCategoriesFunctionsofOSTypesofOSFilesystem1516SoftwareCategoriesApplicationsoftwareiswrittentoaddress

ourspecificneeds—tosolveproblemsinthe

realworld.Wordprocessingprograms,games,pictureediting,videoplayerareallapplicationsoftware.Systemsoftwareconsistsoftheprogramsthatcontrolormaintaintheoperationsofthecomputeranditsdevices.Itprovidesthetoolsandanenvironmentinwhichapplicationsoftwarecanbecreatedandrun.SoftwareCategories17SystemSoftwareWithintheclassofsystemsoftwarearetwocategories:Utilitysoftwareprogramsforperformingvariousactivitiesfundamentaltocomputerinstallations,butnotpartoftheOS.(Examplesincludeformattingadisk,networking,copyingfiles,usingamodem,anddatacompression.)OperatingSystemsprogramscontaininginstructionsthatworktogethertocoordinatealltheactivitiesamongcomputerhardwareresources18OperatingSystemAnoperatingsystemalsoconsistsoftwoparts.Thekernelmanagescomputerresources,suchasmemoryandinput/outputdevices.Theshellprovidesaninterfacethroughwhichahumancaninteractwiththecomputer.Anoperatingsystemalsoallowsapplicationprogramstointeractwiththeothersystemresources.19OutlineWhatisOSandwhy?DevelopmentofOSSoftwareCategoriesFunctionsofOSTypesofOSFilesystem20Everyoperatingsystemperformsthreebasicfunctions:managescomputerresourcesmemory,CPU,andprocessesprovidesaninterfacethroughwhichahumancaninteractwiththecomputerallowsanapplicationprogramtointeractwithothersystemresources21OperatingSystemFunctionsOperatingSystemFunctionsResourcemanagementMemorymanagementProcessmanagementCPUschedulingOtherfunctions22MemoryManagementMemorymanagementoptimizestheuseofRAMKeepingtrackofwhichpartsofmemoryarecurrentlyusedandbywhomDecidingwhichprocessesanddatatobemovedintoandoutofmemoryAllocatingandde-allocatingmemoryspaceasneededMultiprogrammingisthetechniqueofkeepingmultipleprogramsinmainmemoryatthesametime.ProtectedfromoneanotherTheseprogramscompeteforaccesstotheCPUtoimproveefficiency.MemoryManagementOperating

systemJob1Job2Job3Memory

partitionsPhysicalmemspace(e.g.,2G)VirtualmemspaceDisk04G04G04GOperatingSystemFunctionsResourcemanagementMemorymanagementProcessmanagementCPUschedulingOtherfunctions25TimesharingMultiprogrammingallowedmultipleprocessestobeactiveatonce,whichgaverisetotheabilityforprogrammerstointeractwiththecomputersystemdirectly,whilestillsharingitsresources.Atimesharingsystemallowsmultipleuserstointeractwithacomputeratthesametime.Inatimesharingsystem,eachuserhashisorherownvirtualmachine,inwhichallsystemresourcesare(ineffect)availableforuse.26ProcessManagementAprocesscanbedefinedasaprograminexecution.Theoperatingsystemperformsprocessmanagement

tocarefullytracktheprogressofeachprocessandallofitsintermediatestates.27ProcessManagementTheProcessStatesTheprocesslifecycle28ProcessManagementHowanoperatingsystemhandlesprogramsdirectlyaffectsyourproductivity29SingleuserandmultiuserSingletaskingandmultitaskingForegroundandbackgroundPreemptivemultitaskingMultiprocessingAsingleuseroperatingsystemallowsonlyoneusertorunoneprogramatatime.Amultiuseroperatingsystemenablestwoormoreuserstorunaprogramsimultaneously.Amultitaskingoperatingsystemallowsasingleusertoworkontwoormoreapplicationsthatresideinmemoryatthesametime.Amultiprocessingoperatingsystemcansupporttwoormoreprocessorsrunningprogramsatthesametime.ProcessManagementProcessManagement31ForgroundandBackgroundOperatingSystemFunctionsResourcemanagementMemorymanagementProcessmanagementCPUschedulingOtherfunctions32CPUSchedulingTheoperatingsystemdetermineswhichprocessinmemoryisexecutedbyCPUNonpreemptiveschedulingoccurswhenthecurrentlyexecutingprocessgivesuptheCPUvoluntarily.Preemptiveschedulingoccurswhentheoperatingsystemdecidestofavouranotherprocess,preemptingthecurrentlyexecutingprocess.33OperatingSystemFunctionsResourcemanagementMemorymanagementProcessmanagementCPUschedulingOtherfunctions34WatchDemoExp#5OtherOSfunctions:35StartandshutdownacomputerProvideauserinterfaceConfiguredevicesEstablishanInternetconnectionMonitorperformanceProvideutilitiesAutomaticallyupdateControlanetworkAdministersecurityOperatingSystemFunctions36OperatingSystemFunctionsSystemBootingTheprocessofstartingorrestartingacomputeriscalledbooting37ColdbootTurningonacomputerthathasbeenpoweredoffcompletelyWarmbootUsingtheoperatingsystemtorestartacomputerSystemShuttingDownAnoperatingsystemincludesvariousshutdownoptions38SleepmodesavesanyopendocumentsandprogramstoRAM,turnsoffallunneededfunctions,andthenplacesthecomputerinalow-powerstateHibernatesavesanyopendocumentsandprogramstoaharddiskbeforeremovingpowerfromthecomputerUserInterface39Auserinterface(UI)controlshowyouenterdataandinstructionsandhowinformationisdisplayedonthescreenWithagraphicaluserinterface(GUI),youinteractwithmenusandvisualimages40Thecomponents:UserInterfaceUserInterfaceWithacommand-lineinterface,auserusesthekeyboardtoenterdataandinstructions41DeviceDriverAdriverisasmallprogramthattellstheoperatingsystemhowtocommunicatewithaspecificdevicePlugandPlayautomaticallyconfiguresnewdevicesasyouinstallthem4243DeviceDriver44DeviceDriverNetworkSupportOperatingsystemstypicallyprovideameanstoestablishInternetconnections45PerformanceMonitorAperformancemonitor

isaprogramthatassessesandreportsinformationaboutvariouscomputerresourcesanddevices46SystemUpdateAutomaticupdate

automaticallyprovidesupdatestotheprogram47UserApplicationsOperatingsystemsoftenprovideuserswiththecapabilityof:48ManagingfilesSearchingforfilesViewingimagesSecuringacomputerUninstallingprogramsCleaningupdisksDefragmentingdisksDiagnosingproblemsBackingupfilesanddisksSettingupscreensaversUtilityProgramsAutilityprogram

isatypeofsystemsoftwarethatallowsausertoperformmaintenance-typetasks49UtilityProgramsAfilemanager

isautilitythatperformsfunctionsrelatedtofilemanagementDisplayingalistoffilesOrganizingfilesinfoldersCopying,renaming,deleting,moving,andsortingfilesandfoldersCreatingshortcuts50UtilityProgramsAsearchutility

isaprogramthatattemptstolocateafileonyourcomputerbasedoncriteriayouspecify51UtilityProgramsAdiskcleanuputilitysearchesforandremovesunnecessaryfilesDownloadedprogramfilesTemporaryInternetfilesDeletedfilesUnusedprogramfiles52UtilityProgramsAdiskdefragmenter

reorganizesthefilesandunusedspaceonacomputer’sharddisksothattheoperatingsystemaccessesdatamorequicklyandprogramsrunfaster53UtilityProgramsAbackuputility

allowsuserstocopyfilestoanotherstoragemediumArestoreutility

reversestheprocessandreturnsbackedupfilestotheiroriginalform54OutlineWhatisOSandwhy?DevelopmentofOSSoftwareCategoriesFunctionsofOSTypesofOSFilesystem55TypesofOperatingSystems56Stand-AloneOperatingSystemsAstand-aloneoperatingsystem

isacompleteoperatingsystemthatworksonadesktopcomputer,notebookcomputer,ormobilecomputingdevice57WindowsXP/Vista/7MacOSXUNIXLinuxStand-AloneOperatingSystemsWindows7isMicrosoft’smatureOSandisavailableinmultipleeditions:58Windows7HomeWindows7ProfessionalWindows7UltimateWindows7BusinessStand-AloneOperatingSystems59Windows7Stand-AloneOperatingSystemsTheMacintoshoperatingsystem

hassetthestandardforoperatingsystemeaseofuse60Stand-AloneOperatingSystemsUNIXisamultitaskingoperatingsystemdevelopedintheearly1970sLinuxisanopen-source,popular,multitaskingUNIX-typeoperatingsystem61ServerOperatingSystemsWindowsServer2008UNIXLinuxSolaris62ServerOSSomeoperatingsystemsaredesignedtoworkwithaserveronanetworkAserveroperatingsystem

organizesandcoordinateshowmultipleusersaccessandshareresourcesonanetworkAnetworkadministratorusestheserveroperatingsystemto:Addandremoveusers,computers,andotherdevicesInstallsoftwareandadministernetworksecurity63ServerOSprovidesprivatestorageforeachuser.Itcheckseachuserrequestwiththeaccesscontrollistanddecidetograntordenypermissiontosystemresources.64ServerOS65ServerOSOncetheuseraccessesthenetwork,additionalrestrictionsareusuallyineffect,suchaswhichfilestheusercanaccessandwhatcanbedonetothesefiles.EmbeddedOperatingSystemsAnembeddedoperatingsystem

residesonaROMchiponamobiledeviceorconsumerelectronicdevice66AndroidWindowsMobilePalmOSiPhoneOSBlackberryEmbeddedLinuxSymbianOSOutlineWhatisOSandwhy?DevelopmentofOSSoftwareCategoriesFunctionsofOSTypesofOSFilesystem6768FilemanagementFileSystemsandDirectoriesDescribethepurposeoffiles,filesystems,anddirectoriesDistinguishbetweentextandbinaryfilesIdentifyvariousfiletypesbytheirextensionsDescribeadirectorytreeIdentifyabsoluteandrelativepathsforadirectorytree69Anamedgroupoffiles.AlsocalledafolderFile

AnamedcollectionofrelateddataFilesystemTheoperatingsystem'slogicalviewofthefilesitmanagesDirectoryFileSystemsFiles70What’sfilepicture

textprogram

datamusicFileisthecollectionofallkindsofinformation,oranamedcollectionofrelateddataFiles71

Fileisstoredin

secondarystorage

Afileisasetofdatathathasbeengivena

name.FileType72

FiletypeProgramfiles-containsinstructionstotellthecomputerwhattodo.MicrosoftWord,Photoshop,AutoCAD

DataFiles

-notexecutableandonlyusedwithaprogram.Worddocument,textfile,Excelfile,PowerPointfileTextfileAfileinwhichthebytesofdataareorganizedascharactersfromtheASCIIorUnicodecharactersetsBinaryfileAfilethatcontainsdatainaspecificformat,requiringinterpretationTextandBinaryFilesThetermstextfileandbinaryfilearesomewhatmisleading…Theyseemtoimplythattheinformationinatextfileisnotstoredasbinarydata.Ultimately,allinformationonacomputerisstoredasbinarydigits.Thesetermsrefertohowthosebitsareformatted:aschunksof8or16bits,interpretedascharacters,orinsomeotherspecialformat.73FileTypesMostfiles,whethertheyareintextorbinaryformat,containaspecifictypeofinformation. Forexample,afilemaycontainaprogram,animage,oranaudioclip.Thekindofinformationcontainedinadocumentiscalledthefiletype. Mostoperatingsystemsrecognizealistofspecificfiletypes.74Filenamesareoftenseparated,usuallybyaperiod,intotwoparts:MainnameFileextensionThefileextensionindicatesthetypeofthefile.SomecommonfiletypesandtheirextensionsFileTypes7576FilesaredistinguishedbytheirnamesFilename=mainname.

extensionname（扩展名）Namingrule:uselettersandnumbers,avoidusingspaceorotherpunctuations(标点符号),startwithaletter.

letters:bothupperandlowercasedigits:0－9

others：-,_FileNamea.txt张三.doc77FileNameInmultiusersystems,fileprotectionisofprimaryimportance.Wedon’twantoneusertobeabletoaccessanotheruser’sfilesunlesstheaccessisspecificallyallowed.Afileprotectionmechanismdetermineswhocanuseafileandforwhatgeneralpurpose.FileProtection78FileProtectionAfile’sprotectionsettingsintheUnixoperatingsystemisdividedintothreecategoriesOwnerGroupWorld79Adirectoryoffilescanbecontainedwithinanotherdirectory. Thedirectorycontaininganotherisusuallycalledtheparentdirectory,andtheoneinsideiscalledasubdirectory.Directorytree:Alogicalviewofafilesystem;astructureshowingthenesteddirectoryorganizationofafilesystem.Rootdirectory:

Thedirectoryatthehighestlevel.DirectoryTrees8081Eachofastoragedevicesisidentifiedbyadeviceletter.Adeviceletterisalwaysfollowedbyacolon（冒号）underwindowsOS.Mainharddisk:CdriveC:AdditionalstoragedevicescanbeassignedlettersfromDthroughZ.DeviceletterandrootdirectoryDARootDirectory82DirectoryTrees83DirectoryTreesPath:

Atextdesignationofthelocationofafileorsubdirectoryinafilesystem,consistingoftheseriesofdirectoriesthroughwhichyoumustgotofindthefile.Absolutepath:Apaththatbeginsattherootandspecifieseachstepdownthetreeuntilitreachesthedesiredfileordirectory.Relativepath:Apathnamethatbeginsatthecurrentworkingdirectory.PathNamesAtanypointintime,youcanbethoughtofasworkinginaparticularlocation(thatis,aparticularsubdirectory).Workingdirectory:Thesubdirectoryinwhichyouareworking.Workingdirectory86D:\Courses\Computer\2011\OS.pptDriveprimarysecondary……filenameextensionLetterfolderfolderrootfoldersubfolderAssumeweareat‘Computer’,then:Absolutepath:D:\Courses\Computer\2011\OS.pptRelativepath:2011\OS.pptPathNames87

Filemanagementhelpsyouorganizeyourfilessothatyoucanfindandusethemmoreefficiently.FilemanagementFilemanagementcanbe……WithinanapplicationprogramUsingaspecialfilemanagementutilitybytheoperatingsystem.MicrosoftwordWindowsExplorer(资源管理器)88FilemanagementFilemanagement8990viewViewsinaWindowIconListDetail……Filemanagement91Clipboard（剪贴板）Fi