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1、文献翻译作业下属学院专业班级学号姓 名指导教师骆挺职称 讲师-年-月-日<文献翻译：原文>DEADLOCKS Silberschatz,A.Galvin,P.B&G.Gagne.OperatingSystemConcepts[M].Beijing:HigherEducationPress,2004:243-270Inamultiprogrammingenvironment,severalprocessesmaycompeteforafinitenumberofrecoursesprocessrequestsresources;iftheresourcesarenotava
2、ilableatthetime,theprocessentersawaitstate.Waitingprocessesmayneveragainchangestate,becausetheresourcestheyhaverequestedareheldbyotherwaitingprocesses.Thissituationiscalledadeadlock.Inadeadlock,processesneverfinishexecutingandsystemaretiedup,preventingotherjobsfromstarting.Beforewediscuss
3、thevariousmethodsfordealingwiththedeadlockproblem,weshalldescribefeaturesthatcharacterizedeadlock.1.TheNecessaryConditionsofDeadlocksAdeadlocksituationcanraiseifthefollowingfourconditionsholdsimultaneouslyinasystem:·Mutualexclusion:Atleastoneresourcemustbeheldinanon-sharablemode;thatis,on
4、lyoneprocessatatimecanusetheresource.Ifanotherprocessrequeststhatresource,therequestingprocessmustbedelayeduntiltheresourcehasbeenreleased.·Holdandwait:Aprocessmustbeholdingatleastoneresourcesandwaitingtoacquireadditionalresourcesthatarecurrentlybeingheldbyotherprocesses.·Nopreemption:Res
5、ourcescannotbepreempted;thatis,aresourcecanbereleasedonlyvoluntarilybytheprocessholdingit,afterthatprocesshascompleteditstask.·Circularwait:Aset{P0,P1,….Pn}ofwaitingprocessesmustexistsuchthatP0iswaitingforaresourcethatisheldbyP1,P1iswaitingforaresourcethatisheldbyP2,…,Pn-1iswaitingforares
6、ourcethatisheldbyP0.Weemphasizethatallfourconditionsmustholdforadeadlocktooccur.Thecircular-waitconditionimpliesthehold-and-waitcondition,sothefourconditionsarenotcompletelyindependent.2.MethodsforHandingDeadlocksPrincipally,wecandealwiththedeadlockprobleminoneofthreeways:·Wecanuseaprotoc
7、olitpreventoravoiddeadlocks,ensuringthatthesystemwillneverenteradeadlockstate.·Wecanallowthesystemtoenteradeadlocksystem,detectit,andrecover.·Wecanignoretheproblemaltogether,andpretendthatdeadlockneveroccurinthesystems.Thissolutionisusedbymostoperatingsystems,includ
