Test Bank For Guide to Operating Systems - 10th - 2021 All Chapters - 9780357433836.pdf

GOVERNMENT OF TAMILNADU DIRECTORA
b b b


TE OF TECHNICAL EDUCATION CHENNAI –
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600 025 b b




STATE PROJECT COORDINATION UNIT
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Diploma in Computer Engineering
b b b

CoursebCode:b1052b

Mb–bScheme

e-TEXTBOOK
onbOPERATI
NGbSYSTEMS
for
III Semester COMPUTER ENGINEERING
b b b




ConvenerbforbCOMPUTERbENGGbDiscipline:
Mr.D.ARULbSELVAN
HOD/POSTbDIPLOMAbINbCOMPUTERbAPPLICATIONSbTH
IAGARAJARbPOLYTECHNICbCOLLEGE
SALEM
TeambMembersbforbIndustrialbInstrumentation:

1. Mrs.bP.SARADHAbHOD/C
OMPUTERbENGG,
GOVERNMENTbPOLYTECHNICbCOLLEGEb
KRISHNAGIRIb-635b001

2. Mrs.bB.SANTHIbMEENAbLECTUR
ERb/COMPUTERbENGG
GOVERNMENTbPOLYTECHNICbCOLLEGEb
KRISHNAGIRIb-635b001

3. Mrs.V.BHUVANESWARIbLECTUR
ERb/COMPUTERbENGG
GOVERNMENTbPOLYTECHNICbCOLLEGE
bDHARMAPURI-635b205




ValidatedbbybMrs.P.S.NEELAYATHA
KSHI
LECTURER(SEL.GRADE)/COMPUTERbENGGbVA
LIVALAMbDESIKARbPOLYTECHNICbCOLLEGE,bN
AGAPATTINAM-611001

, UNIT- I b




INTRODUCTION TO OPERATING SYSTEMS
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OBJECTIVES
o Tobdescribebthebbasicbconceptbofboperatingbsystem.
o Tobgivebanboverviewbofbgenerationsbofboperatingbsystem.
o Tobexplorebseveralbtypesbofboperatingbsystems
o Tobprovidebinformationbaboutbmajorbcomponentsbofboperatingbsystem
o Tobdescribebthebvariousbservicesbofboperatingbsystemb.
o Tobknowbaboutb thebvariousbwaysbofbstructuringbanboperatingbsystem.
INTRODUCTION
Anboperatingbsystembisbabprogrambthatbmanagesbabcomputer’sbhardware.bItbalsobprovid
esbabbasisbforbapplicationbprogramsbandbactsbasbanbintermediarybbetweenbthebcompute
rbuserbandbthebcomputerbhardware.bThisbunitbprovidesbabgeneralboverviewbaboutbthebmajorbc
omponentsbofboperatingbsystembandbitsbfunctionsb.bAlsobgivesbinformationbaboutbvariousbservic
esbofbanboperatingbsystembprovides,bhowbtheybarebprovided,bhowbtheybarebdebugged,bandbabo
utb thebvariousbmethodologiesbofboperatingb systembstructures.


BASICS OF AN OPERATING SYSTEM
b b b b


AnbOperatingbSystemb(OS)bisbanbinterfacebbetweenbabcomputerbuserbandbcomputerbhardwa
re.bAnboperatingbsystembisbabsoftwarebwhichbperformsballbthebbasicbtasksblikebfilebmanagement,
bmemorybmanagement,bprocessbmanagement,bhandlingbinputbandboutput,bandbcontrollingbperi

pheralbdevicesbsuchbasbdiskbdrivesbandbprinters.bAnbOSbisbbasicallybanbintermediatebagentbbet
weenbthebuserbandbthebcomputerbhardware.
SomebpopularbOperatingbSystemsbincludebLinux,bWindows,bOSbX,bVMS,bOS/400,bAIX,bz/O
S,betc.


1.1.1 DEFINITION

Anboperatingbsystembisbabprogrambthatbactsbasbanbinterfacebbetweenbthebuserbandbthebcomp
uterbhardwarebandbcontrolsbthebexecutionbofballbkindsbofbprograms.

FollowingbarebsomebofbimportantbfunctionsbofbanboperatingbSystem.

* MemorybManagement *bProcessorbManagement
* DevicebManagement *bFilebManagement
* Security *bControlboverbsystembperformance
* Jobbaccounting *bResourcesballocatorb&bManager
* Controllingbprogramsbtobpreventberrorsbandbimproperbcomputerbuse.
* Interruptbdriver.

, Figb–b1.1boperatingbsystem

Usersbandbprocessesbaccessbthebcomputersbresourcesbthroughbtheboperatingbsystem.

1.1.2 GENERATIONSbOFbOPERATINGbSYSTEM
Operatingbsystemsbhavebabseriesbofbrevolutionarybchangesbcalledbgenerations.bInbcomputer
sbhardware,bgenerationsbhavebbeenbmarkedbbybmajorbadvancesbinbcomponentrybfrombvacuum
btubesb(firstbgeneration)btobtransistorsb(Secondbgeneration),btobintegratedb circuitryb(Thirdbgener

ation),btoblargebscalebandbveryblarge.bscalebintegratedbcircuitryb(Forthbgeneration).bThebsucces
sivebhardwarebgenerationsbhavebeachbbeenbaccompaniedbbybdramaticbreductionsbinbcosts,bsiz
e,bheat,bemission,bandbenergybconsumption,bandbtrybdramaticbincreasesbinbspeedbandbstorageb
capacity.

1. Theb1940'sb-bFirstbGenerations
2. Theb1950'sb-bSecondbGeneration
3. Theb1960'sb-bThirdbGeneration
4. FourthbGenerationb(1971-Present)bMicroprocessors
5. FifthbGenerationb(PresentbandbBeyond)bArtificialbIntelligence

1.1.2.1 ThebFirstbgeneration
Thebearliestbelectronicbdigitalbcomputersbhadbnoboperatingbsystems.bMachinesbofbthebtimeb
werebsobprimitivebthatbprogramsbwereboftenbenteredbonebbitbatbtimebonbrowsbofbmechanicalbswit
chesb(plugbboards).bProgrammingblanguagesbwerebunknownb.bTheboperatingbsystemsbofbthebfir
stbgenerationbwerebdesignedbtobsmoothbthebtransitionbbetweenbjobs.bBeforebthebsystemsbwereb
developedbabgreatbdealbofbtimebwasblostbbetweenbthebcompletionbofbonebjobbandbthebinitiationbo
fbthebnext.bThisbwasbthebbeginningbofbbatchbprocessingbsystemsbinbwhichbjobsbwerebgatheredbi
nbgroupsborbbatches.bOncebabjobbrunning,bitbhadbtotalbcontrolbofbthebmachine.bAnbeachbjobbtermi
nated,bcontrolbwasbreturnedbtobtheboperatingbsystem.Thisbmodebofboperationbisbcalledbserialbpr
ocessing.Disadvantagesbofbserialbprocessing
1. Scheduling
2. SetupbTime


1.1.2.2 ThebSecondbgeneration

, Bybthebearlyb1950's,bthebroutinebhadbimprovedbsomewhatbwithbthebintroductionbofbpunchbcar
ds.bThebGeneralbMotorsbResearchbLaboratoriesbimplementedbthebfirstboperatingbsystemsbinbea
rlyb1950'sbforbtheirbIBMb701.bThebsystembofbtheb50'sbgenerallybranbonebjobbatbabtime.bThesebwer
ebcalledbsingle-
streambbatchbprocessingbsystemsbbecausebprogramsbandbdatabwerebsubmittedbinbgroupsborbb
atches.
ThebsecondbgenerationbofbOSbwasbcharacterizedbbybthebdevelopmentbofbsharedbsystemsbwithb
multiprogrammingbandbbeginningsbofbmultiprocessing.bInbmultiprogrammingbsystemsbseveralb
userbprogramsbarebinbmainbstoragebatboncebandbthebprocessorbisbswitchedbrapidlybbetweenbthe
bjobs.bInbmultiprocessingbsystemsbseveralbprocessorsbarebusedbonbabsinglebcomputerbsystembt

obincreasebthebprocessingbpowerbofbthebmachine.

1.1.2.3 ThebThirdbGeneration

Thebsystemsbofbtheb1960'sbwerebalsobbatchbprocessingbsystems,bbutbtheybwerebablebtobtak
ebbetterbadvantagebofbthebcomputer'sbresourcesbbybrunningbseveralbjobsbatbonce.bSoboperating
bsystemsbdesignersbdevelopedbthebconceptbof bmultiprogramming binbwhichbseveralbjobsbarebinb

mainbmemorybatbonce;
Forbexample,bonbthebsystembwithbnobmultiprogramming,bwhenbthebcurrentbjobbpausedbtobw
aitbforbotherbI/Oboperationbtobcomplete,bthebCPUbsimplybsatbidlebuntilbthebI/Obfinished.bThebsoluti
onbforbthisbproblembthatbevolvedbwasbtobpartitionbmemorybintobseveralbpieces,bwithbabdifferentbj
obbinbeachbpartition.bWhilebonebjobbwasbwaitingbforbI/Obtobcomplete,banotherbjobbcouldbbebusing
bthebCPU.


Anotherbmajorbfeaturebinbthird-
generationboperatingbsystembwasbthebtechniquebcalledbspoolingb(simultaneousbperipheralbope
rationsbonbline).bInbspooling,babhigh-
speedbdeviceblikebabdiskbinterposedbbetweenbabrunningbprogrambandbablow-
speedbdevicebinvolvedbwithbthebprogrambinbinput/output.
Anotherbfeaturebpresentbinbthisbgenerationbwasbtime-
sharingbtechnique,babvariantbofbmultiprogrammingbtechnique,binbwhichbeachbuserbhasbanbon-
lineb(i.e.,bdirectlybconnected)bterminal.bTime-
sharingbsystemsbwerebdevelopedbtobmultiprogrammingblargebnumberbofbsimultaneousbinteracti
vebusers.

1.1.2.3.1 Multiprogramming

Sharingbthebprocessor,bwhenbtwoborbmorebprogramsbresidebinbmemorybatbthebsamebtime,bisb
referredbasbmultiprogramming.bMultiprogrammingbassumesbabsinglebsharedbprocessor.bMulti
programmingbincreasesbCPUbutilizationbbyborganizingbjobsbsobthatbthebCPUbalwaysbhasbonebto
bexecute.




AnbOSbdoesbthebfollowingbactivitiesbrelatedbtobmultiprogramming.

• Theboperatingbsystembkeepsbseveralbjobsbinbmemorybatbabtime.
• Thisbsetbofbjobsbisbabsubsetbofbthebjobsbkeptbinbthebjobbpool.
• Theboperatingbsystembpicksbandbbeginsbtobexecutebonebofbthebjobsbinbthebmemory.
• Multiprogrammingboperatingbsystemsbmonitorbthebstatebofballbactivebprogramsbandbsyst
embresourcesbusingbmemorybmanagementbprogramsbtobensuresbthatbthebCPUbisbnever
bidle,bunlessbtherebarebnobjobsbtobprocess.




1.1.2.3.2 TimebSharing