操作系统原理2

Chapter2:Operating-SystemStructures沈卓炜h@[e-mail]四牌楼校区文正楼南205，83790819-802九龙湖校区计算机楼316Chapter2:Operating-SystemStructures„OperatingSystemServices„UserOperatingSystemInterface„UserOperatingSystemInterface„SystemCalls„TypesofSystemCalls„SystemPrograms„SystemPrograms„OperatingSystemDesignandImplementation„OperatingSystemStructure„VirtualMachines„VirtualMachines„OperatingSystemGenerationSoutheastUniversity2.2„SystemBootChapter3:Operating-SystemStructures(6thEdition)Structures(6Edition)„SystemComponents„SystemComponents„OperatingSystemServices„SystemCalls„SystemPrograms„SystemPrograms„SystemStructure„VirtualMachines„SystemDesignandImplementation„SystemDesignandImplementation„SystemGenerationSoutheastUniversity2.3OperatingSystemConceptsCommonSystemComponentsCooSysteCopoets„ProcessManagementg„MainMemoryManagementFilMt„FileManagement„I/OSystemManagementyg„Secondary-StorageManagement„Networking„ProtectionSystem„ProtectionSystem„Command-InterpreterSystemSoutheastUniversity2.4OperatingSystemConceptsProcessManagementocessaageet„Aprocessisaprograminexecution.f„Theoperatingsystemisresponsibleforthefollowingactivitiesinconnectionwithgprocessmanagement.‹Processcreationanddeletion‹Processcreationanddeletion.‹processsuspensionandresumption.‹Piifhif‹Provisionofmechanismsfor:9processsynchronization9processcommunication9DeadlockhandlingSoutheastUniversity2.5OperatingSystemConceptsMain-MemoryManagementaeoyaageet„Memoryisalargearrayofwordsorygybytes,eachwithitsownaddress.ItisarepositoryofquicklyaccessibleisarepositoryofquicklyaccessibledatasharedbytheCPUandI/Odevicesdevices.„Mainmemoryisavolatilestoragedevice.Itlosesitscontentsinthecaseofsystemfailure.caseofsystemfailure.SoutheastUniversity2.6OperatingSystemConceptsMain-MemoryManagement(Cont.)yg()„Theoperatingsystemisresponsibleforpgypthefollowingactivitiesinconnectionswithmemorymanagement:withmemorymanagement:‹Keeptrackofwhichpartsofmemoryarecurrentlybeingusedandbywhomcurrentlybeingusedandbywhom.‹Decidewhichprocessestoloadwhenbilblmemoryspacebecomesavailable.‹Allocateanddeallocatememoryspaceasneeded.SoutheastUniversity2.7OperatingSystemConceptsFileManagementeaageet„Therearedifferenttpesofphsicalmediato„Therearedifferenttypesofphysicalmediatostoreinformation.Eachofthemhasitsowncharacteristicsandphysicalorganization„OperatingSystemprovidesauniformlogical„OperatingSystemprovidesauniformlogicalviewofinformationstorage,i.e.,file.Afililltifltdifti„Afileisacollectionofrelatedinformationdefinedbyitscreator.Commonly,filesrepresentprograms(bothsourceandobjectforms)anddata.SoutheastUniversity2.8OperatingSystemConceptsforms)anddata.FileManagement(Cont.)eaageet(Cot)„Theoperatingsstemisresponsibleforthe„Theoperatingsystemisresponsibleforthefollowingactivitiesinconnectionswithfilemanagement:‹Filecreationanddeletion.‹‹Directorycreationanddeletion.‹Supportofprimitivesformanipulatingfilesand‹Supportofprimitivesformanipulatingfilesanddirectories.‹Mifiltdt‹Mappingfilesontosecondarystorage.‹Filebackuponstable(nonvolatile)storageSoutheastUniversity2.9OperatingSystemConceptsmedia.I/OSystemManagement/OSysteaageet„TheI/Osbsstemconsistsof„TheI/Osubsystemconsistsof:‹Abuffer-cachingsystem‹Ageneraldevice-driverinterface‹Driversforspecifichardwaredevices‹DriversforspecifichardwaredevicesSoutheastUniversity2.10OperatingSystemConceptsSecondary-StorageManagementSecodayStoageaageet„Sincemainmemory(primarystorage)isvolatileandtoosmalltoaccommodatealldataandprogramspermanently,thepgpy,computersystemmustprovidesecondarystoragetobackupmainmemorystoragetobackupmainmemory.„Mostmoderncomputersystemsusedisksastheprincipleon-linestoragemedium,forbothprogramsanddata.pgSoutheastUniversity2.11OperatingSystemConceptsSecondary-StorageManagement(Ct)(Cont.)„Theoperatingsystemisresponsibleforthefollowingactivitiesinconnectionwithdiskmanagement:g‹Freespacemanagement‹Storageallocation‹Storageallocation‹DiskschedulingSoutheastUniversity2.12OperatingSystemConceptsNetworking(DistributedSystems)etog(stbutedSystes)„Adistribtedsstemisacollection„Adistributedsystemisacollectionprocessorsthatdonotsharememoryoraclock.Eachprocessorhasitsownlocalmemory.y„Theprocessorsinthesystemareconnectedthroughacommunicationnetworkthroughacommunicationnetwork.„Communicationtakesplaceusingaprotocol.SoutheastUniversity2.13OperatingSystemConceptsNetworking(DistributedSystems)(Ct)(Cont.)„Adistribtedsstemproidesseraccessto„Adistributedsystemprovidesuseraccesstovarioussystemresources.„Accesstoasharedresourceallows:‹Computationspeed-up‹Computationspeed-up‹Increaseddataavailability‹‹EnhancedreliabilitySoutheastUniversity2.14OperatingSystemConceptsProtectionSystemotectoSyste„Protectionreferstoamechanismfor„Protectionreferstoamechanismforcontrollingaccessbyprograms,processes,oruserstobothsystemanduserresources.„Theprotectionmechanismmust:„Theprotectionmechanismmust:‹distinguishbetweenauthorizedandunauthorizedusageusage.‹specifythecontrolstobeimposedandmeansforftenforcement.SoutheastUniversity2.15OperatingSystemConceptsCommand-InterpreterSystemCoadtepeteSys