微机接口技术本章主要内容Windows内核驱动程序概述两种类型的驱动程序WIN2000系统的分层结构执行部件内核驱动程序的分类内核模式驱动程序的分类内核模式驱动程序的分类内核模式驱动程序的分类内核模式驱动程序的分类WDM驱动程序操作系统设计目标9.1Windows驱动程序模型Abusdriverservicesabuscontroller,adapter,orbridge.Busdriversarerequireddrivers;thereisonebusdriverforeachtypeofbusonamachine.Microsoftprovidesbusdriversformostcommonbuses.IHVsandOEMscanprovideotherbusdrivers.AbusfilterdrivertypicallyaddsvaluetoabusandissuppliedbyMicrosoftorasystemOEM.Therecanbeanynumberofbusfilterdriversforabus.Lower-levelfilterdriverstypicallymodifythebehaviorofdevicehardware.TheyareoptionalandaretypicallysuppliedbyIHVs.Therecanbeanynumberoflower-levelfilterdriversforadevice.Afunctiondriveristhemaindriverforadevice.Afunctiondriveristypicallywrittenbythedevicevendorandisrequired(unlessthedeviceisbeingusedinrawmode).Upper-levelfilterdriverstypicallyprovideadded-valuefeaturesforadevice.TheyareoptionalandaretypicallyprovidedbyIHVs.WDM的新特点9.1.1WDM的基本结构系统为帮助软件管理硬件而创建的一个数据结构.WDM中包括物理设备对象(PDO)、功能设备对象(FDO)和过滤器设备对象(FiDO)三种。驱动程序分类功能驱动程序总线驱动程序过滤器驱动程序2526279.1.2I/O请求包（IRP）WDM中I/O请求包的运行机制如下：ThesubsystemcallsanI/Osystemservicetoopenanamedfile.TheI/Omanagercallstheobjectmanagertolookupthenamedfileandtohelpitresolveanysymboliclinksforthefileobject.Italsocallsthesecurityreferencemonitortocheckthatthesubsystemhasthecorrectaccessrightstoopenthatfileobject.Ifthevolumeisnotyetmounted,theI/Omanagersuspendstheopenrequesttemporarilyandcallsoneormorefilesystemsuntiloneofthemrecognizesthefileobjectassomethingithasstoredononeofthemass-storagedevicesthefilesystemuses.Whenthefilesystemhasmountedthevolume,theI/Omanagerresumestherequest.TheI/OmanagerallocatesmemoryforandinitializesanIRPfortheopenrequest.Todrivers,anopenisequivalenttoa"create"request.TheI/Omanagercallsthefilesystemdriver,passingittheIRP.ThefilesystemdriveraccessesitsI/OstacklocationintheIRPtodeterminewhatoperationitmustcarryout,checksparameters,determinesiftherequestedfileisincache,and,ifnot,setsupthenext-lowerdriver'sI/OstacklocationintheIRP.BothdriversprocesstheIRPa