计算机导论课件：Chapter04 Operating Systems and File Management

Chapter4

OperatingSystemsandFileManagementChapterContentsSectionA:OperatingSystemBasicsSectionB:Today’sOperatingSystemsSectionC:FileBasicsSectionD:FileManagementSectionE:BackupSecurityChapter4:OperatingSystemsandFileManagement2SectionA:OperatingSystemBasicsChapter4:OperatingSystemsandFileManagement3OperatingSystemTasksAnoperatingsystemisatypeofsystemsoftwarethatactsasthemastercontrollerforallactivitiesthattakeplacewithinacomputersystemChapter4:OperatingSystemsandFileManagement4OperatingSystemTasksChapter4:OperatingSystemsandFileManagement5OperatingSystemTasksMultitaskingprovidesprocessandmemorymanagementservicesthatallowtwoormoretasks,jobs,orprogramstorunsimultaneouslyWithinasingleprogram,multithreadingallowsmultipleparts,orthreads,torunsimultaneouslyAmultiprocessingcapabilitysupportsadivisionoflaboramongalltheprocessingunitsAmemoryleakiswhenanapplicationrequestsmemorybutneverreleasesitCancauseanapplicationnottofunctionproperlyChapter4:OperatingSystemsandFileManagement6OperatingSystemTasksOperatingSystemCategoriesSingle-useroperatingsystemMultiuseroperatingsystemServeroperatingsystemDesktopoperatingsystemMobileoperatingsystemChapter4:OperatingSystemsandFileManagement7TheBootProcessDuringthebootprocess,theoperatingsystemkernelisloadedintoRAMThekernelprovidesessentialoperatingsystemservicesYourcomputer’ssmallbootstrapprogramisbuiltintospecialROMcircuitryhousedinthecomputer’ssystemunitChapter4:OperatingSystemsandFileManagement8TheBootProcessChapter4:OperatingSystemsandFileManagement9TheBootProcessUserInterfacesThecombinationofhardwareandsoftwarethathelpspeopleandcomputerscommunicatewitheachotherChapter4:OperatingSystemsandFileManagement11UserInterfacesBasiccontrolelementsofaGUIDesktopTaskbarordockApplicationwindowStartscreenIconTileButtonToolbarMenuMenubarRibbonSubmenuDialogboxChapter4:OperatingSystemsandFileManagement12UserInterfacesChapter4:OperatingSystemsandFileManagement13UserInterfacesChapter4:OperatingSystemsandFileManagement14UserInterfacesChapter4:OperatingSystemsandFileManagement15UserInterfacesMenus,submenus,anddialogboxesChapter4:OperatingSystemsandFileManagement16QuestionAcomputerhandlesmanytaskssimultaneously.Whichoneofthefollowingreferstotheprocessor’sabilitytohandlemultipletasks,ratherthantheoperatingsystem’sabilitytodoso?A.Multi-coreB.MultitaskingC.MultithreadingD.MultiprocessingChapter4:OperatingSystemsandFileManagement17AnswerASectionB:Today’sOperatingSystemsChapter4:OperatingSystemsandFileManagement19MicrosoftWindowsChapter4:OperatingSystemsandFileManagement20WindowsTimelineChapter4:OperatingSystemsandFileManagement21VariousWindowsChapter4:OperatingSystemsandFileManagement22MacOSChapter4:OperatingSystemsandFileManagement23MacOSChapter4:OperatingSystemsandFileManagement24MacOSPopularvirtualmachinesoftwaresuchasVMwareandParallelsDesktopcanrunonmostcomputerswithIntelmicroprocessors,includingIntelMacs,PCs,andgenericLinuxcomputersChapter4:OperatingSystemsandFileManagement25MacOSXTimelineChapter4:OperatingSystemsandFileManagement26iOSiOSisanoperatingsystemfortheAppleiPhone,andwasderivedfromtheMacOSXcodeChapter4:OperatingSystemsandFileManagement27AndroidAndroidisamobileoperatingsystemthatisapopularplatformfortabletcomputers,smartphones,andebookreadersChapter4:OperatingSystemsandFileManagement28UNIXandLinuxTheUNIXoperatingsystemwasdevelopedin1969atAT&T’sBellLabsDependableinmultiuserenvironmentsLinuxisanoperatingsystemdistributedalongwithitssourcecodeunderthetermsofaGPL(GeneralPublicLicense)ALinuxdistributionisadownloadthatcontainstheLinuxkernel,systemutilities,graphicaluserinterface,applications,andaninstallationroutineChapter4:OperatingSystemsandFileManagement29UNIXandLinuxChapter4:OperatingSystemsandFileManagement30BlackBerryOSBlackBerryOSisaproprietaryoperatingsystemproducedbyRIMKeyfeatureistheabilitytoworkwithcorporatee-mailsoftwaresystemsproducedbyMicrosoftandIBMRIMpioneeredpushtechnology,inwhichnotificationsareautomaticallysenttoadeviceChapter4:OperatingSystemsandFileManagement31HandheldandTabletOperatingSystemsChapter4:OperatingSystemsandFileManagement32OSComparisonOSMarketSharesQuestionToday’spopularoperatingsystemsincludeWindows,MacOS,Linux,Android,andGoogleChrome.Eachhasstrengthsandweaknessesthatareimportanttounderstand.Whichofthefollowingstatementsiscorrect?A.GoogleChromeisbuiltontheWindowskernel,soitisidealfornetbooksbecauseithasgoodresistancetomalware.B.Ifyoudon’tliketheuserinterfaceforWindowsbutwanttorunthevastvarietyofWindowssoftware,youcaninstallLinux.C.LinuxandMacOShaveareputationforbeingmorestablethanWindows.D.WindowsincludessoftwarecalledBootCampthatallowsPCstobootintodifferentoperatingsystems,suchasMacOS,Linux,Chrome,andAndroid.AnswerCSectionC:FileBasicsChapter4:OperatingSystemsandFileManagement37FileNamesandExtensionsYoumustadheretofile-namingconventionswhensavingfilesCasesensitivityMaximumlengthSpacesallowedNumbersallowedCharactersnotallowedFilenamesnotallowedFileextensionsprovidecluestothefilecontentsChapter4:OperatingSystemsandFileManagement38FileDirectoriesandFoldersTodesignateafile’slocation,youmustfirstspecifythedevicewherethefileisstoredThemainharddiskusuallyisreferredtoasdriveCMacsdonotusedrivelettersAdiskpartitionisasectionofharddiskdrivethatistreatedasaseparatestorageunitPartitionscanbeassigneddrivelettersPartitionsarenotthesameasfoldersChapter4:OperatingSystemsandFileManagement39FileDirectoriesandFoldersChapter4:OperatingSystemsandFileManagement40FileDirectoriesandFoldersEverystoragedevicehasadirectorycontainingalistofitsfilesRootdirectorySubdirectoryDepictedasfoldersAcomputer’sfilelocationisdefinedbyafilespecification,orpathChapter4:OperatingSystemsandFileManagement41FileFormatsAfileformatreferstotheorganizationandlayoutofdatathatisstoredinafileTheformatofafileusuallyincludesaheader,data,andpossiblyanend-of-filemarkerAfileheaderisasectionofdataatthebeginningofafilethatcontainsinformationaboutafileAfileextensiondoesnotreallydefinetheformatofafileChapter4:OperatingSystemsandFileManagement42FileFormatsAsoftwareapplicationcanopenfilesthatexistinitsnativefileformat,plusseveraladditionalfileformatsChapter4:OperatingSystemsandFileManagement43FileFormatsChapter4:OperatingSystemsandFileManagement44QuestionSupposeafriendsendsyouafilecalledTwain.dll.Fromthefilename,whatcanyoudeduce?A.Thatitisawordprocessingdocument,probablyaboutMarkTwain.B.ThatyoushouldbeabletoopenitusingMicrosoftWord.C.Thatthefileextensionmakesitavirus.D.Thatitisasupportprogramfile,perhapspartofthedevicedriverforyourscanner.Chapter4:OperatingSystemsandFileManagement45AnswerDSectionD:FileManagementChapter4:OperatingSystemsandFileManagement47Application-BasedFileManagementApplicationsgenerallyprovideawaytoopenfilesandsavetheminaspecificfolderonadesignatedstoragedeviceChapter4:OperatingSystemsandFileManagement48Application-BasedFileManagementChapter4:OperatingSystemsandFileManagement49FileManagementMetaphorsAfilemanagementutilityhelpsyoumanagefilesinyouroperatingsystemStoragemetaphorshelpyouvisualizeandmentallyorganizethefilesonyourdisksandotherstoragedevicesLogicalstoragemodelsChapter4:OperatingSystemsandFileManagement50FileExplorerChapter4:OperatingSystemsandFileManagement51FileExplorerFileExplorerhelpsyoumanipulatefilesandfoldersinthefollowingways:RenameCopyMoveDeleteWindowsoffersasetofpreconfiguredpersonalfolders,suchasMyDocumentsandMyMusic,forstoringyourpersonaldatafilesChapter4:OperatingSystemsandFileManagement52FileExplorerChapter4:OperatingSystemsandFileManagement53FileManagementTipsUsedescriptivenamesMaintainfileextensionsGroupsimilarfilesOrganizeyourfoldersfromthetopdownConsiderusingdefaultfoldersUsePublicfoldersforfilesyouwanttoshareDonotmixdatafilesandprogramfilesChapter4:OperatingSystemsandFileManagement54FileManagementTipsDon’tstorefilesintherootdirectoryAccessfilesfromtheharddiskFollowcopyrightrulesDeleteorarchivefilesyounolongerneedBeawareofstoragelocationsBackupChapter4:OperatingSystemsandFileManagement55PhysicalFileStorageThephysicalstoragemodeldescribeswhathappensonthedisksandinthecircuitsStoragemediamustbeformattedbeforeitcanstorefilesTheformattingprocessdividesthediskintotracksandsectorsChapter4:OperatingSystemsandFileManagement56PhysicalFileStorageChapter4:OperatingSystemsandFileManagement57PhysicalFileStorageThefilesystemkeepstrackofthenamesandlocationsoffilesNTFSMasterFileTable(MFT)Chapter4:OperatingSystemsandFileManagement58PhysicalFileStorageDeletingafilechangesthestatusofthatfile’sclusterstoemptyandremovesthefilenamefromtheindexfileThefile’sdataisstillthereFileshreddersoftwareoverwrites“empty”sectorswithrandom1sand0sFilesintheWindowsRecycleBinandsimilarutilitiescanbeundeletedChapter4:OperatingSystemsandFileManagement59PhysicalFileStorageFragmentedfilesarestoredinnoncontiguousclustersanddecreaseperformanceDefragmentationutilitiesrearrangefilessothattheyarestoredincontiguousclustersChapter4:OperatingSystemsandFileManagement60QuestionBeforedonatingyourcomputertoacharitableorganization,youcanmakesureyourpersonaldatacannotbeaccessedfromtheharddiskby:A.Deletinganyfilesthatcontainpersonaldata.B.DeletingfilescontainingpersonaldataandthenemptyingtheRecycleBinorTrash.C.Deletingallthefilesandfoldersonyourcomputer’sharddisk.D.Deletingallfilesandfoldersandthenusingfileshreddersoftware.Chapter4:OperatingSystemsandFileManagement61AnswerDSectionE:BackupSecurityBackupBasicsFileCopiesSynchronizationWindowsBackupBackupSoftwareVirtualMachinesTabletandSmartphoneBackupChapter4:OperatingSystemsandFileManagement63BackupBasicsAbackup

storesthefilesneededtorecoverdatathat’sbeenwipedoutbyoperatorerror,viruses,orhardwarefailuresYourbackupscheduledependsonhowmuchdatayoucanaffordtoloseYoushouldtestyourbackupbytryingtorestoreonefileThebackupdeviceyouselectdependsonthevalueofyourdata,yourcurrentequipment,andyourbudgetOnlinebackupservicesChapter4:OperatingSystemsandFileManagement64BackupBasicsChapter4:OperatingSystemsandFileManagement65FileCopiesUniquefilesaredifficulttoreproduceManuallycopyingandpastingrequiresyoutoselectthefilesanddestinationdeviceeachtimeChapter4:OperatingSystemsandFileManagement66SynchronizationSynchronization

comparesthecontentoffilesontwodevicesandmakesthemthesameAprogramcalledTimeMachinesuppliedwithMacOSXisagoodexampleofsynchronizationsoftwareSynchronizeseveryhourChapter4:OperatingSystemsandFileManagement67SynchronizationChapter4:OperatingSystemsandFileManagement68WindowsBackupWindows8includesasynchronizationutilitycalledFileHistoryChapter4:OperatingSystemsandFileManagement69WindowsBackupAfullsystembackupincludesacopyofeveryfilestoredonyourcomputer’sharddriveAbootdiskisaremovablestoragemediumcontainingtheoperatingsystemfilesneededtobootyourcomputerwithoutaccessingtheharddiskArecoverydiskisabootableCD,DVD,orothermediathatcontainsacompletecopyofyourcomputer’sharddiskasitexistedwhenthecomputerwasnewChapter4:OperatingSystemsandFileManagement70WindowsBackupArecoverypartitionislocatedonthecomputer’sharddiskandcontainsthenecessaryfilestorestoreacomputertoitsoriginalstateTheWindowsRegistryisanimportantgroupoffilesusedbytheWindowsoperatingsytsemtostoreconfigurationinformationaboutallthedevicesandsoftwareinstalledonacomputersystemArestorepointisasnapshotofyourcomputersettingsChapter4:OperatingSystemsandFileManagement71WindowsBackupChapter4:OperatingSystemsandFileManagement72BackupSoftwareBackupsoftwareisasetofutilityprogramsdesignedtobackupandrestoresomeorallofthefilesonacomputer’sprimarystoragedeviceAbackupmadebycopyingallthefilestoabackupdeviceiscalledafullbackupAdifferentialbackupmakesabackupofonlythosefilesthatwereaddedorchangedsinceyourlastfullbackupsessionAnincrementalbackupmakesabackupofthefilesthatwereaddedorchangedsincethelastbackup—notnecessarilythefilesthatchangedfromthelastfullbackupChapter4:OperatingSystemsandFileManagement73BackupSoftwareRestoringacomputerusuallyentailsseveralstepsAbare-metalrestorerestoresthecomputerinasinglestepAdiskimageisabit-by-bitcopyofthedatafromallsectorsofadiskChapter4:OperatingSystemsandFileManagement74VirtualMachinesChapter4:OperatingSystemsandFileManagement75TabletandSmartphoneBackupHandhelddevicesareusuallybackedupbysynchingthemtoadesktoporlaptopcomputerSynchingisusuallyinitiatedbytetheringyourhandhelddevicetoafull-sizecomputerusingaUSBcableiPhones,iPods,andiPadssynchwithiTunessoftware,andyouhavetheoptiontoencryptthebackuptopreventyourdatafromexposureifyourcomputerfallsvictimtoanunauthorizedintrusionManyAndroiddevicesincludebackupsoftware,usuallyaccessiblefromtheSettingsiconChapter4:OperatingSystemsandFileManagement76TabletandSmartphoneBackupChapter4:OperatingSystemsandFileManagement77QuestionCopyingimportantdatafilesfromyourcomputer’sharddisktoanopticaldiskorflashdriveisasimplewaytobackupdata.Itisnotatotalbackupsolution,however.Whynot?A.Youcannotrestorethesefilestoanewharddiskwithouttheactivationcodes.B.Thebackupisbootable,butitwon’tstartyourcomputeriftheharddiskfails.C.Youhavenotbackedupyourprogramsoryourpersonalsettings.D.YouhavenotbackeduptherestorepointsneededtoreconfiguretheWindowsRegistryforanewharddisk.Chapter4:OperatingSystemsandFileManagement78AnswerCFastPollTrue/FalseQuestions

AnswerAforTrueandBforFalse(1)Anoperatingsystemmanagesacomputer’sresourcessuchastheprocessor,