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1、国立中山大学资讯工程学系國立中山大學資訊工程學系92學年度第2學期博士班資格考試作業系統OperatingSystemConcepts-45%ModernOperatingSystems-15%Other-40%1.Deadlock[15%,A.Silberschatz,P.Galvin,andG.Gagne,OperatingSystemConcepts,JohnWiley&Sons,Inc.,6thEd,Chapter8,Exercises9]Considerasystemconsistingofmres
2、ourcesofthesametype,beingsharedbynprocesses.Resourcescanberequestedandreleasedbyprocessesonlyoneatatime.Showthatthesystemisdeadlockfreeifthefollowingtwoconditionshold:a.Themaximumneedofeachprocessisbetween1andmresourcesb.Thesumofallmaximumneedsislessthanm+n
3、2.MassStorage[15%,A.Silberschatz,P.Galvin,andG.Gagne,OperatingSystemConcepts,JohnWiley&Sons,Inc.,6thEd,Chapter14,Exercises2]Supposethatadiskdrivehas5000cylinders,numbered0to4999.Thedriveiscurrentlyservingarequestatcylinder143,andthepreviousrequestwasatcylin
4、der125.Thequeueofpendingrequests,inFIFOorder,is86,1470,913,1774,948,1509,1022,1750,130Startingfromthecurrentheadposition,whatisthetotaldistance(incylinders)thatthediskarmmovestosatisfyallthependingrequests,foreachofthefollowingdiskschedulingalgorithms?A.FCF
5、SB.SSTFC.SCAND.LOOKE.C-SCAN3.CPUScheduling[15%,A.Silberschatz,P.Galvin,andG.Gagne,OperatingSystemConcepts,JohnWiley&Sons,Inc.,6thEd,Chapter6,Exercises4]Supposethatthefollowingprocessesarriveforexecutionatthetimesindicated.Eachprocesswillrunthelistedamountof
6、time.Inansweringthequestions,usenonpreemptiveschedulingandbasealldecisionsontheinformationyouhaveatthetimethedecisionmustbemade.ProcessArrivalTimeBurstTimeP10.08P20.65P31.02(A).WhatistheaverageturnaroundtimefortheseprocesseswiththeFCFSschedulingalgorithm?(B
7、).WhatistheaverageturnaroundtimefortheseprocesseswiththeSJFschedulingalgorithm?(C).TheSJFalgorithmissupposedtoimproveperformance,butnoticethatwechosetorunprocessP1attime0becausewedidnotknowthattwoshorterprocesseswouldarrivesoon.Computewhattheaverageturnarou
8、ndtimewillbeiftheCPUisleftidleforthefirst1unitandthenSJFschedulingisused.RememberthatprocessesP1andP2arewaitingduringthisidletime,sotheirwaitingtimemayincrease.Thisalgorithmcouldbeknownasfuture-knowled
