《操作系统》B卷.docx
- 文档编号:27972593
- 上传时间:2023-07-07
- 格式:DOCX
- 页数:8
- 大小:30.66KB
《操作系统》B卷.docx
《《操作系统》B卷.docx》由会员分享,可在线阅读,更多相关《《操作系统》B卷.docx(8页珍藏版)》请在冰豆网上搜索。
《操作系统》B卷
诚信应考,考试作弊将带来严重后果!
华南理工大学期末考试
《操作系统》试卷B
注意事项:
1.考前请将密封线内填写清楚;
2.所有答案请答在答题纸上;
3.考试形式:
闭卷;
4.本试卷共三大题,满分100分,考试时间120分钟。
题号
一
二
三
总分
得分
评卷人
一、单项选择题(30ptstotal,2ptseach)
1.()Theoperatingsystemisnotresponsibleforthefollowingactivitiesinconnectionwithprocessmanagement?
_____.
A.Suspendingandresumingprocesses
B.Providingmechanismforprocesssynchronization
C.Handlingdeadlock
D.Keepingtrackoffreememory
2.()Whichofthefollowingprocessschedulealgorithmcanleadtostarvation?
_______.
A.FCFSB.RoundRobinC.SJFD.GuaranteedScheduling
3.()_______registercontainsthesizeofaprocess.
A.BaseB.LimitC.IndexD.Stackpointer
4.()Deadlockcanariseiffourconditionsholdsimultaneously.Whichofthefollowingisnotoneofthesefourconditions?
________.
A.mutualexclusionB.busywaitingC.holdandwait
D.nopreemptionE.circularwait
5.()Letgraphrepresent“resourceallocationgraph”.Whichstatementiswrong?
________.
A.Ifgraphcontainscycle,andthereisonlyoneinstanceperresourcetype,thenthereisdeadlock.
B.Ifgraphcontainscycle,andtherecanbeseveralinstancesperresourcetype,thentheremayormaynothavedeadlock
C.Ifgraphcontainsnocycle,thennodeadlock
D.Ifnodeadlock,thengraphcontainsnocycle
6.()Theabilityofacomputersystemtoswitchexecutionamongseveraljobsthatareinmemoryatthesametimeiscalled______.
A.timeslicingC.multiprocessing
B.multiprogrammingD.multitasking
7.()Inthereaders-writersproblem,processespandqareallowedtosimultaneouslyaccessthesharedresourceifandonlyif_____.
A.pandqarebothreading.C.Eitherporqorbothisreading
B.pandqarebothwritingD.Eitherporqorbothiswriting
8.()Supposethatamachinehas48-bitvirtualaddressand32-bitphysicaladdress.Ifpagesare4KB,howmanyentriesareinthepagetableifithasonlyasinglelevel?
A.227B.216C.224D.236
9.“Computingthetrack,sector,andheadforadiskread”isdoneinwhichlayers?
A.InterrupthandlersC.Device-independentOSsoftware
B.DevicedriversD.User-levelI/Osoftware
10.()Iftherearenonamecollisionsinafilesystem,theeasiestmethodistouse______.
A.single-leveldirectorysystemC.single-levelortwo-leveldirectorysystem
B.two-leveldirectorysystemD.hierarchicaldirectorysystem
11.()Acomputerhasfourpageframes.Thetimeofloading,timeoflastaccess,andtheRandMbitsforeachpageareasshownbelow(thetimesareinclockticks):
PageLoadedLastref.RM
012628010
123026501
214027000
311028511
WhichpagewillNRU,LRUandsecondchancereplacerespectively?
A.2,2,1B.2,3,1C.2,1,2D.3,1,2
12.()Acomputerhassixtapedrives,withnprocessescompetingforthem.Eachprocessmayneedtwodrives.Forwhichvaluesofnisthesystemdeadlockfree?
A.8B.7C.6D.5
13.()Thebeginningofafreespacebitmaplookslikethisafterthediskpartitionisfirstformatted:
100000000000(thefirstblockisusedbytherootdirectory).Thesystemalwayssearchesforfreeblocksstartingatthelowest-numberedblock,soafterwritingfileA,whichusessixblocks,thebitmaplookslikethis:
1111111000000000.Showthebitmapafterthefollowingadditionalaction:
fileBiswritten,usingfiveblocks.
A.1000000111110000C.1111111111111100
B.1111111111110000D.1111111000001100
14.()InwhichofthefourI/Osoftwarelayersis“Writingcommandstothedeviceregisters”isdone?
A.InterrupthandlersC.Device-independentOSsoftware
B.DevicedriversD.User
15.()Howmuchcylinderskewisneededfora7200-rpmdiskwithatrack-to-trackseektimeof1msec?
Assumingthatthediskhas200sectorsof512byteseachoneachtrack.______
A.12B.24C.48D.40
二、简答题(15ptstotal,5ptseach)
1.(5pts)Listatleastthreekeydifferencesbetweenuser-levelthreadsandkernel-levelthreads.
2.(5pts)Inavirtualmemorysystem,doesaTLBmissimplyadiskoperationwillfollow?
Whyorwhynot?
3.(5pts)Howmanydiskoperationsareneededtoopenthefile/usr/student/lab/test.doc?
Why?
(Assumethatnothingelsealongthepathisinmemory.Alsoassumethatalldirectoriesfitinonediskblock.)
三、综合题(55ptstotal)
1.(10pts)Supposethatinabus,theactivitiesofthedriverandtheconductorareasfollowing:
driver:
conductor:
Startthebus;closethedoor;
Drivethebus;sellthetickets;
Stopthebus;openthedoor;
PleaseusesemaphoreandP/Voperationstosynchronizetheactivitiesofthem.
2.(8pts)FivebatchjobsAthroughE,arriveatacomputercenteratalmostthesametime.Theyhaveestimatedrunningtimesof10,6,2,4,and8minutes.Their(externallydetermined)prioritiesare3,5,2,1,and4,respectively,with5beingthehighestpriority.Foreachofthefollowingschedulingalgorithms,determinethemeanprocessturnaroundtime.Ignoreprocessswitchingoverhead.
Job
Arrivaltime
Executiontime
Priority
A
0
10
3
B
0
6
5
C
0
2
2
D
0
4
1
E
0
8
4
(1)Roundrobin
(2)Priorityscheduling
(3)First-come,first-served(runorder10,6,2,4,8).
(4)Shortestjobfirst
3.(10pts)Asystemhasfiveprocessesandfourallocatableresources.Thecurrentallocationandadditionalneedsareasfollows:
Process
Allocation
Need
Available
A
B
C
D
A
B
C
D
A
B
C
D
P1
P2
P3
P4
P5
0
1
1
0
0
0
0
3
3
0
3
0
5
3
1
2
0
4
2
4
0
1
2
0
0
0
7
3
6
6
1
5
5
5
5
2
0
6
2
6
1
6
2
2
Pleaseanswerthefollowingquestions:
(1)Isthisstatesafe?
Why?
(2)Therequest(1,2,2,2)ofP3canbegrantedornot?
Why?
V
PID
VPN
1
9
0x0DF0
1
A
0x3630
1
C
0x1B70
1
C
0x37C1
0
F
0x1F04
1
A
0x3640
1
9
0x1FFF
1
A
0x23A4
1
9
0x3004
1
A
0x0D7C
1
C
0x0DF0
0
B
0x1F04
1
A
0x0DF0
1
9
0x020D
1
A
0x31A2
1
C
0x07C1
4.(10pts)Givena36-bitprocessorwith4activeprocessesbeingexecutedconcurrently.Pleaseanswerthefollowingquestions.Showalltheaddressesofyouranswerinhexnumber.Ifatranslationcannotbefound,enterpagefault.
(1)Assumeaninvertedpagetable(IPT)isusedbytheOS.TheIPTisshownbelow(OnlyValid,PIDandVPNareshown).Eachpagesizeis4MB.What“virtualaddress”ofwhich“process”mapstothephysicaladdress“0x363055B”?
(2)Nowweswitchtouseanindex-basedlinearpagetable,howmuchmemory(inKB)isrequiredforjustprocessA?
Assumeeachpagetableentry(PTE)containsavalidanddirtybit.
5.(8pts)AUNIXfilesystemhas1-KBblocksand32bitdiskaddresses.Whatisthemaximumfilesizeifi-nodescontain10directentries,andonesingle,double,andtripleindirectentryeach?
6.(9pts)Supposethatadiskdrivehas300cylinders,numbered0to299.Thedriveiscurrentlyservingarequestatcylinder143.Thequeueofpendingrequests,inFIFOorder,is
86,147,291,18,95,151,12,175,30
Startingfromthecurrentheadposition,whatisthetotaldistance(incylinders)thatthediskarmmovestosatisfyallthependingrequests,foreachofthefollowingdisk-schedulingalgorithms?
(1)First-ComeFirst-Served(FCFS)
(2)ShortestSeekFirst(SSF)
(3)ElevatorAlgorithm(Assumethatinitiallythearmismovingtowardscylinder0)
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 操作系统