中科大操作系统原理与实现课件13_io

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1、操作系统原理与设计第13章IOSystems（IO管理）陈香兰中国科学技术大学计算机学院2009年09月01日......提纲.I/OHardwarePollingInterruptsDirectMemoryAccess(DMA)I/OhardwaresummaryApplicationI/OInterfaceBlockandCharacterDevicesNetworkDevicesClocksandTimersBlockingandNonblockingI/OKernelI/OSubsystemI/OSchedulingBufferingCaching,Spooling&de

2、vicereservationErrorHandlingI/OProtectionKernelDataStructuresTransformingI/ORequeststoHardwareOperationsPerformance小结和作业.......OverviewII/OdevicesIvarywidelyIThecontrolofdevicesconnectedtothecomputerisamajorconcernofOSdesigners.HowOSmanagesandcontrolsvariousperipherals？......Outline.I/OHardw

3、arePollingInterruptsDirectMemoryAccess(DMA)I/OhardwaresummaryApplicationI/OInterfaceBlockandCharacterDevicesNetworkDevicesClocksandTimersBlockingandNonblockingI/OKernelI/OSubsystemI/OSchedulingBufferingCaching,Spooling&devicereservationErrorHandlingI/OProtectionKernelDataStructuresTransformin

4、gI/ORequeststoHardwareOperationsPerformance小结和作业.......I/OHardwareIIIncrediblevarietyofI/Odevices......I/OHardwareIIICommonconcepts:CPU!PORT!BUS!ControllerIPortIBus(daisychainorshareddirectaccess)IPCI(PeripheralComponentInterconnect)ISCSI(Smallcomputersystemsinterface)IExpansionbusIControlle

5、r(hostadapter)IHowcantheprocessorcommandcontroller?IControllerhasoneormoreregistersfordataandcontrolsignals.ITheprocesscommunicateswiththecontrollerbyreadingandwritingbitpatternsintheregisters.II/OinstructionscontroldevicesITwocommunicationapproaches......I/OHardwareIIIIDirectI/Oinstructions

6、IAccesstheportaddressIEachporttypicallycontainsoffourregisters,i.e.,status,control,data-inanddata-out.Ie.g.,In,outIMemory-mappedI/OIe.g.,0xa0000˜0xfffffarereservedtoISAgraphicscardsandBIOSroutinesIDeviceI/OPortLocationsonPCs(partial)......I/OHardwareIV......I/OControlMethods1.Polling2.Interrup

7、ts3.DMA4.(在汤书上：还有通道的概念)......PollingIINeedhandshakingIDeterminesstateofdeviceIcommand-readyIIncommandregisterI1:acommandisavailableforthecontrollerIbusyIInstatusregisterI0:readyforthenextcommand;1:busyIErrorIToindicatewhetheranI/Oisok.......Polling