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1、东南大学考试卷（B卷）自觉遵守考场纪律如考试作弊此答卷无效学号姓名密封线课程名称操作系统考试学期07-08-2得分适用专业计算机应用考试形式闭卷考试时间长度120分钟一、Definitions[5X6=30pts]Givethetechnicaltermthatbestfitsthesedefinitions1.Portionofaprogramthataccessessharedvariablesandthatnotwoprocessescanbeexecutingthiscodethatmanipulatessharedvariablesatthesametime.2.I
2、tisamethodofoverlappingtheI/Oofajobwiththatjob’sowncomputation.Theideaissimple.Afterareadoperationcompletesandthejobisabouttostartoperatingonthedata,theinputdeviceisinstructedtobeginthenextreadimmediately.TheCPUandinputdevicearethenbothbusy.3.Somedevices,suchastapedrivesandprinters,cannotus
3、efullymultiplextheI/0requestsofmultipleconcurrentapplications.Thesubsystemscancoordinateconcurrentoutputtoaseparatediskfile.Forinstance,Whenanapplicationfinishesprinting,thesubsystemcopiesthequeuedfilestotheprinterone,atatime.4.Unusedroutineisneverloaded.5.Aprocessisbusyswappingpagesinandou
4、t.6.Asmalloperatingsystemcorethatprovidesbasicscheduling,memorymanagementandcommunicationserviceswhilerelyingonprocessestoperformtheotherrequiredfunctionalitytraditionallyassociatedwiththeoperatingsystem.共页第页二、Comparisons[6+9=15pts]CompletethefollowingcomparisonsusingTrue,FalseorPossible1.[
5、6pts]BlockingI/oversusNoblockingI/OPointofComparisonBlockingI/ONoblockingI/OI/OcallreturnsasmuchasavailableImplementedviamulti-threading2.[9pts]ThreadsversusprocessesPointofComparisonThreadsProcessesShareallglobalvariablesExecuteinseparateaddressspacesRequirelesstimetocreate,terminateandswi
6、tchfromonetoanother三、Computing[10+12=22pts]1.Supposethatadiskdrivehas5000cylinders,numbered0to4999.Thedriveiscurrentlyservingarequestatcylinder143,andthepreviousrequestwasatcylinder125.Thequeueofpendingrequests,inFIFOorder,is86,1470,913,1774,948,1509,1022,1750,130Startingfromthecurrentheadp
7、osition,whatisthetotaldistance(incylinders)thatthediskarmmovestosatisfyallthependingrequests,foreachofthefollowingdisk-schedulingalgorithms?[10pts]a.SSTFb.LOOK2.Considerthefollowingsetofprocesses,withthelengthoftheCPU-bursttimegiveninmilliseconds:Process
