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&devicereservationErrorHandlingI/OProtectionKernelDataStructuresTransformingI/ORequeststoHardwareOperationsPerformance.小结和作业......OverviewII/OdevicesIvarywidelyIThecontrolofdevicesconnectedtothecomputerisamajorconcernofOSdesigners.HowOSmanagesandcontrolsvariousperipherals？......Outline.I/OHardwarePollingInterruptsDirectMemoryAccess(DMA)I/OhardwaresummaryApplicationI/OInterfaceBlockandCharacterDevicesNetworkDevicesClocksandTimersBlockingandNonblockingI/OKernelI/OSubsystemI/OSchedulingBufferingCaching,Spooling&devicereservationErrorHandlingI/OProtectionKernelDataStructuresTransformingI/ORequeststoHardwareOperationsPerformance.小结和作业......I/OHardwareIIIncrediblevarietyofI/Odevices......I/OHardwareIIICommonconcepts:CPU!PORT!BUS!ControllerIPortIBus(daisychainorshareddirectaccess)IPCI(PeripheralComponentInterconnect)ISCSI(Smallcomputersystemsinterface)IExpansionbusIController(hostadapter)IHowcantheprocessorcommandcontroller?IControllerhasoneormoreregistersfordataandcontrolsignals.ITheprocesscommunicateswiththecontrollerbyreadingandwritingbitpatternsintheregisters.II/OinstructionscontroldevicesITwocommunicationapproaches......I/OHardwareIIIIDirectI/OinstructionsIAccesstheportaddressIEachporttypicallycontainsoffourregisters,i.e.,status,control,data-inanddata-out.Ie.g.,In,outIMemory-mappedI/OIe.g.,0xa0000˜0xfffffarereservedtoISAgraphicscardsandBIOSroutinesIDeviceI/OPortLocationsonPCs(partial)......I/OHardwareIV......I/OControlMethods1.Polling2.Interrupts3.DMA4.(在汤书上：还有通道的概念)......PollingIINeedhandshakingIDeterminesstateofdeviceIcommand-readyIIncommandregister