a dcd filter driver for windows nt tm 4

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1、TMADCDFilterDriverforWindowsNT4XubinHeandQing(Ken)YangDepartmentofElectrical&computerEngineeringUniversityofRhodeIslandKingston,RI02881e-mail:{hexb,qyang}@ele.uri.eduAbstractWiththerapidincreasesinprocessorspeed,diskI/Oswilleventuallybecomeasystembottleneck.Wehaverecentlyproposedane

2、wdiskI/OarchitecturecalledDCD(DiskCachingDisk)thatcandrasticallyimprovediskI/Owriteperformanceasshownbysimulationexperiments[2,4].TovalidatewhetherDCDcanliveuptoitspromiseintherealworld,thispaperpresentsadesignandimplementationofoneDCDconfigurationasafilterdriverunderWindowsNT,oneof

3、themostpopularoperatingsystemsintoday’scomputingworld.Performancemeasurementshavebeencarriedoutusingsyntheticbenchmarksconsistingofrandomfilewrites.ExperimentalresultsshowthatDCDcanimprovethesynchronouswriteperformancebyafactorofupto13.8forintensivesmallwriterequests.Inaddition,beca

4、useDCDusespartofharddiskasdiskcache,ithasexcellentreliabilitybothformeta-dataanduserdata.Furthermore,theDCDdriveriscompletelytransparenttotheupperfilesystem(NTFS)andthelowerlevelphysicaldevice.ItdoesnotrequireanymodificationstotheoriginalOSnortheexistingon-disklayout.Asaresult,itcan

5、beinsertedintotheexistingNTdriverhierarchytoobtainimmediateperformanceandreliabilityimprovements.1IntroductionWiththerapidadvancesinsemiconductortechnology,thespeeddisparitybetweenCPUanddisksincreaseddramaticallyduringthepastdecade.Asaresult,diskoperationsoftendominateusers’waitingt

6、imeintoday’scommercialcomputingenvironments.Asoneoftheleadingoperatingsystems,WindowsNThasanumberofnicefeaturesspecificallytargetedforenhancingperformanceofitsfilesystem(NTFS)anddiskI/Os[5].Forexample,NTFSimprovesperformancebyusingawrite-backcachingstrategy.Thatis,itwritesthemodific

7、ationstothecacheandflushesthecachetodiskasabackgroundthread.NTFSprovidesfilesystemrecoverybasedonatransaction-processingmodelinwhicheachI/Ooperationthataltersfilesystemdataorvolume’sdirectorystructureisconsideredasatransaction.Everysuchtransactionisloggedasalogrecordinalogfile(Figur

8、e1).Riedeletal[3]ha