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1、Processandthread,applicationdomainrelations（进程与线程、应用程序域关系）Processandthread,applicationdomainrelationsProcessemergence:Theprocessiscreatedandmanagedbytheoperatingsystem,leavingtheoperatingsystemwithouttalkingabouttheprocess.First,lookatthefourbasicfea
2、turesoftheoperatingsystem:1.concurrent(concurrence)Thetwoconceptsofparallelismandconcurrencyaretwoconceptsthataresimilaranddistinguished.Parallelismreferstotheoccurrenceoftwoormoreeventsatthesametime,whichisamicroscopicnotionthattheseeventsoccursimul
3、taneouslyinphysics;Concurrencyreferstotheoccurrenceoftwoormoreeventsatthesametimeinterval,whichisamoremacroscopicconcept.Inamultiprogrammingenvironment,concurrencyreferstoaperiodoftimeinamultiprogrammingoperatingatthesametime,butinasingleprocessorsys
4、tem,eachtimecanonlyexecuteaprogram,sothemicroprogramisintheimplementationofthesealternate.Itshouldbenotedthattheusualprogramsarestaticentitiesthatcannotbeexecutedconcurrently.Inorderfortheprogramtoexecuteconcurrently,thesystemmustestablishprocessesfo
5、reachprogramseparately.Process,alsocalledtask,inbrief,referstothebasicunitinthesystemthatcanrunindependentlyandasaresourceallocation.Itisanactiveentity.Multipleprocessescanconcurrentlyexecuteandexchangeinformation.Whenaprocessisrunning,itrequiresacer
6、tainamountofresources,suchasCPU,storagespace,andi/odevices.Thepurposeofintroducingaprocessintoanoperatingsystemistoenabletheprogramtoexecuteconcurrently.2.share(sharing)Sharingmeansthattheresourcesinthesystemcanbesharedbymultipleconcurrentexecutionpr
7、ocessesinmemory.Becauseofthedifferentattributesofresources,therearedifferentwaysfordifferentprocessestoshareresources,whichcanbedividedintomutuallyexclusivesharingandsimultaneousaccess3.virtual(virtual)Bytechnology,aphysicalentitybecomesalogicalcount
8、erpart.Intheoperatingsystem,thevirtualimplementationismainlyachievedbytime-sharing.Obviously,ifnisthenumberofvirtuallogicaldevicescorrespondingtoaphysicaldevice,thespeedofthevirtualdevicemustbe1/nofthephysicaldevicespeed.4.asynchronous(asynchronism)I
