chapter 8 operating systems and utility programs 7. network operating systems课件

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1、CHAPTER8OperatingSystemsandUtilityProgramsNetworkOperatingSystemsOverviewofNOSCharacteristicsNetworkoperatingsystems(NOSs)distributetheirfunctionsoveranumberofnetworkedcomputers.Itthenaddsfunctionsthatallowaccesstosharedresourcesbyanumberofusersconcurrently.NO

2、Scomputerstakeonspecializedrolestoaccomplishconcurrentaccesstosharedresources.Clientsystemscontainspecializedsoftwarethatallowsthemtorequestsharedresourcesthatarecontrolledbyserversystemsrespondingtoaclientrequest.DifferencesBetweenPCandaNOSTheNOSenhancesthere

3、achoftheclientPCbymakingremoteservicesavailableasextensionsofthelocalnativeoperatingsystem.AlthoughanumberofusersmayhaveaccountsonaPC,onlyasingleaccountisactiveonthesystematanygiventime.NOSsupportsmultipleuseraccountsatthesametimeandenablesconcurrentaccesstosh

4、aredresourcesbymultipleclients.TypesofNOSItisimportanttoknowthebasicsaboutpopularNOSfamilies.Manynetworksnowincludemorethanoneservertype,andknowinghowtogetthesediversesystemstointeroperateisanimportantskillforanetworkadministrator.Operatingsystemsonthenetworkh

5、avetheirownlanguage.DifferentNOSvendorsusethesametermsindifferentways.WindowsTerminologyWindowsserver-basednetworksthatrunWindowsNTServerorWindows2000Serverarebasedontheconceptofthedomain.Adomainisagroupofcomputersandusersthatservesasaboundaryofadministrativea

6、uthority.WindowsNTdomainsandWindows2000domains,althoughsimilarinfunction,interactwithoneanotherdifferently.WindowsNT4.0TheDomainStructureofWindowsNTwasentirelydifferentfromtheDomainStructureinWindows2000.InsteadofActiveDirectory,WindowsNTprovidesanadministrati

7、vetoolcalledtheUserManagerforDomains.Itisaccessedfromthedomaincontrollerandisusedtocreate,manage,andremovedomainuseraccounts.WindowsNT4.0EachNTdomainrequiresonePrimaryDomainController(PDC).Thisisa"master"serverthatcontainstheSecurityAccountsManagementDatabase(

8、SAM).AdomaincanalsohaveoneormoreBackupDomainControllers(BDCs),eachofwhichcontainsaread-onlycopyoftheSAM.TheSAMiswhatcontrolstheauthenticationprocesswhenauserlogsontothedomain.Windo