Disk operating system (DOS).PDF

A Disk Operating System (DOS) is a software program that manages and controls the storage and retrieval of data on a computer's hard disk. Initially developed in the early days of personal computing, DOS provided a foundational framework for running applications and managing files on early PCs. It served as the interface between the user and the computer's hardware, facilitating tasks such as file management, running programs, and accessing system resources. Although modern operating systems have largely replaced DOS, its legacy remains significant in the history of computing, shaping the evolution of user interfaces and system architectures.

1. WhatisDOS(DiskOperatingSystem)anditsfunction?
TodayinthisarticleIamgoingtogiveyouinformationaboutDOS(Disk
operatingsystem).Intherealmofcomputing,whereintricaciesaboundand
simplicityoftenconcealsprofoundcomplexity,thereexistsanomnipresentyet
enigmaticentityknownastheDiskOperatingSystem,orDOS.Itisthiselusive
enablerthathasplayedaninstrumentalroleintheevolutionofmoderncomputing,
offeringamyriadoffunctionsthat,whenunraveled,revealatapestryofperplexity
andasymphonyofburstiness.
DOSstandsforMicrosofDiskOperatingSystem.ItisanexampleofSingle
userOperatingSystem.ItisalsocalledCUI(CharaterUserInterface).MS-DOSisa
non-graphicalcommandlineoperatingsystem.OriginallydeveloppedbyMicrosoft
forIBM,MS-DOSwasthestanderdoperatingsystemforIBM-compatiblepersonal
computers.MS-doswasoriginallywrittenbyTimPatersonandintroducedby
MicrosoftinAugust1981.
MS-DOSinnolargeused;however,thecommandsheel/prompt,morecommand
KnownastheWindowscommandlineisstillusedbymanyuserandcomputer.We
giveEnglishlikecommandsandDOSconvertsitintomachinelanguageandafter
thecomputerhasprocessedtheinformation,returnstheresultsinEnglish.
DOS(Diskoperatingsystem)isasingleuser,singletaskingcomputeroperating
systemthatuseraCommandlineinterface.Inspiteofverysmallsizeandrelative
simplicity,itisoneofthemostsuccessfuloperatingsystemsthathasbeen
developedtodate.
I.TheGenesisofDOS:ABriefPrelude
BeforedelvingintothelabyrinthineworldofDOS'sfunctions,letusembarkon
abriefjourneythroughitsorigins.DOS,aforebearofcontemporaryoperating
systems,emergedduringthenascenteraofcomputing.Itsprimordial

2. incarnation,MS-DOS,sawthelightofdayintheearly1980s,markinga
seminalmomentintheannalsoftechnologicalhistory.
II.TheParadoxofSimplicityandComplexity
OneofthedefiningparadoxesofDOSisitsinherentsimplicity.Atitscore,
DOSisacommand-lineinterface,astarkcontrasttothegraphicaluser
interfaces(GUIs)thatgraceourscreenstoday.Yet,withinthissimplicityliesa
profoundcomplexitythathasbeenthehallmarkofitsenduringrelevance.
III.TheMultifacetedFunctionsofDOS
1.FileManagementUnveiled
DOS'sroleasafilemanagementmaestrocannotbeoverstated.Its
command-lineinterfaceallowsuserstonavigate,manipulate,andorganize
filesanddirectorieswithunparalleledprecision.Whetherit'scopying,moving,
renaming,ordeletingfiles,DOSwieldsaversatilearrayofcommandsthat
empowertheusertoorchestratetheirdigitalrealm.
2.MemoryManagementMastery
Thememoryconstraintsofyesteryears'computingenvironmentsdemanded
ingeniousmemorymanagement.DOSexcelledinthisdomain,utilizing
memoryallocationschemeslikeconventional,extended,andexpanded
memorytooptimizesystemresources.Thisintricatememoryjugglingactisa

3. testamenttotheburstinessofDOS,asitdynamicallyallocatedmemoryfor
applications.
3.BootstrappingBrilliance
DOS'sabilitytobootacomputerfromscratchisatestamenttoitsessential
functions.Throughaconvoluteddanceofbootstraploaders,sector-based
diskreads,andBIOSinteractions,DOSinitiatesthecomputingjourney,
breathinglifeintothemachine.
4.ScriptingSorcery
ForthosewhodaredtoexplorethedepthsofDOS,thescriptingcapabilitiesit
offeredwerearevelation.Batchfiles,comprisingaseriesofcommands,
unleashedthepotentialforautomation,allowinguserstoexecutecomplex
sequencesofoperationswithasinglekeystroke.
5.NetworkingNuances
Eveninitssimplestform,DOSshowcaseditsburstinesswhenitcameto
networking.Itintroducedrudimentarynetworkingcommandsthatpavedthe
wayfornascentnetworkedcomputing,demonstratingitsadaptabilityinthe
faceofevolvingtechnology.
IV.TheEnduringLegacy

4. Intheannalsofcomputinghistory,DOSstandsasatestamenttothedualityof
simplicityandcomplexity.Itsmultifacetedfunctions,rangingfromfile
managementtomemoryoptimization,haveleftanindeliblemarkonthedigital
landscape.Whilethegraphicalmarvelsoftoday'soperatingsystemsmay
haveeclipseditsprominence,theburstinessandperplexityofDOScontinue
toresonateasafoundationalpillarofcomputing'sevolution.
FeaturesofDOS:
Therearesomecharacteristicsthatmakeadviseoperatingsystemstandout:
1.DOSdoesnotsupportGUIsanddoesnotrecognizemouseinputs.
2.Adviseoperatingsystemcontrolsfilesanddirectoriesandenablestheloadingand
runningofprograms.Itcanofmanageresourceallocationandmanagehardware
likediscandmemory.
3.Itisanoperatingsystemdesignedforasingleuserthatperformsseveral
functionstoensuresystemsarerunningproperly.
4.ThefileallocationisatabularstructureusedtoholdtheseIDS.
5.DOSneedsaconceptofuserresponsibilities,supportamulti-useroperating
system,andislesssecure.Duetoitssimpleinterfaceandfewfunctionalities,itis
incrediblylight.
WorkingofDOS:
Theprocedureacomputergoesthoughttostartupiscalledthebootprocess.Fora
machinerunningoneofthesix—diskoperatingsystemslistedbelow,forexample.
1.TheMastersBootRecordisreadbytheread—onlymemory(ROM)bootstrap
loaderbeforeittransfersControltoit.
2.Thebootrecordstartsthecomputerbyloadingtheoperatingsystemintomemory
andgivingitcontrol.

5. 3.Datafromamagneticdiseistransferredtothecomputer'sprimarymemory,the
randomaccessmemory.
4.Thecomputeroffersservalapplicationprogramminginterface(APIc)for
applications,suchascharacterinput/output,termination,andmanaginguserinput
thoughtakeyboard.
5.TheOSfurtheroffersfile,management,whichgroups,reads,andwritesdata
storedonstorage.Ahierarchicalsystemcomprisingfolders,Subdirectories,andfiles
isusedtoarrangethefiles.
Q.HowtoopenDOSinWindows?
=Start>AllProgram>Accessories>CommandPrompt.
Start>Run-CMDorCommand
Q.HowtomakeMS-DOSWindowMaximize(fullScreem)?
=ALT+ENTER(applicableforWindowsxpnotfor7,8&10)
Q.HowtoexitfromDOS?
=ExitCommandisusetoexitCommandPrompt.
Q.HowtochangeDriveinMS-DOS?
=Syntax:- DriveName:(pressenterkey)
Example-D:
BOOTING:
Processthatstartsupacomputeriscalledbooting.Itcheckforproperfunctioningof
alltheHardware(peripheral)devicesattachedwiththesystem.Itsearchsforthe
operatingsystemand,whenlocated,loadsitintothemainmemory(RAM).

6. CommandPromptandMS-DOSthesamething?
Whiletheydosharethesameattributes,theyareabitdifferent.Asopposed
toMS-DOS,acommandpromptisGUI-based,soitacceptsmouseinput.
Limitations:
•Itisnotamultitaskingoperatingsystemthatiswecannotruntoomany
applicationsinthebackground.
•Filesonthesystemcanbeeasilydeletedorthesystemcanalsobeeasily
destroyed.
•Itdoesnotprovideanywarningmessagebeforeyoudeleteorperformany
unwantedtasklikeinwindowsorLinux.
•Itistext-basedanditdoesnothaveanygraphicaluserinterface.
•Notsecuretobeusedinanykindofpublicnetwork.
•Encryptionisnotsupported.
•Difficultyinmemoryaccess.
•Mousecannotbeusedtogiveinputs.
Readmore:Dellsupportassistnobootabledevicesfound
DOS(Diskoperatingsystem)Command

7. DOShasarelativelysmallnumberofcommands,andanevensmallernumberof
commonlyusedonesMoreover,theseCommandsaregenerallyinflexiblebecause,
incontrasttolinuxandotherUbix—likeoperatingsystems,theyaredesignedto
accommodatefewoperatingorargument(I.e.,valuethatcanbepassedtothe
Commands).
Commandsarepredefineinstructionwhichisusedtoperforminternalandexternal
operation.
AcommandcanbegivenincapitalsorSmalllettersalso.AfterTypingDOS
commandwemuctpressenterkey.
MS-DOSfileandfiletypes:
AcomputerfilecreatedbyanapplicationrunningundertheDOSoperating
system.iscalledanMS-DOSfile.TherearethreemainfilesofDOS.During
theBootingprocess,thecomputerloadstheoperatingsystemintoitsmemory.
DOSbootinginvolvesreadingthefollowingfilesintomemorynamely
•IO.SYS:Ahiddenexecutablebinaryfilethatprocessesinstructionsthattell
theoperatingsystem(OS)howthecomputerissetupwhenitisbootedor
started.ItcontainsthedefaultMS-DOSdevicedrivers(hardwareinterfacing
routines)andtheDOSinitializationprogram.
•MSDOS.SYS:TheMSDOS.SYSfileisahidden,system,read-onlyfile
createdontherootofthebootdrive.Thereareseveralconfigurationsthatcan
bechangedusingthisfile.MostvaluesintheMSDOS.SYSareeither0or1,
whichisofforon.
•COMMAND.COM:COMMAND.COMisthedefaultcommand-lineinterpreter
forMS-DOS.Itisthedefaultuserinterfaceaswell.COMMAND.COMisthe
commandshellonMS-DOSandPC-DOS,aswellasversionsofWindows
thatdependonDOS.GivesusersacommandlineinterfacetoDOSaswellas
awaytorunscriptscalled“batchfiles”withthe.BATfileextension.
DOSToday:TheRiseandFallofDiskoperatingsystem:
DOShasbeenasignificantpartoftheevolutionoftheOS.However,itspeakhas
longbeenover.Herearethereasonswhy:
1.OutdatedTechnology:

8. DOSlacksthefeaturesandfunctionalitiesoftoday'sOSeslikeWindows,macOS,
andlinux.
2.User—FriendlyInterfaces:
DOSusestexttounderstandwhattheuserwantstodo.StandaloneDoscomputers
cannotrungraphics—basedapplicationsasefficientlyasmodernoperating
systems.
3.LockofHardwaresupport:
DOSstruggleswithmodernHardwareanddrives,makingeverydayuseofmodern
devicesandperipheralsimpractical.
4.LimitedsoftwareCompatibility:
MostsoftwareapplicationsareforWindows,macOS,orLinux,makingrunning
modernapplicationsonDOSChallengingduetocompatibilityissues.
5.SecurityConcerns:
DOSlacksessentialsecurityfeatures,makingitvulnerabletoviruses,malwareand
cyberattacks.However,companiescontinuetodevelopcustomsystemonit.
DifferentVersionsofMS-DOS
•MS-DOS1.x
•MS-DOS2.x
•MS-DOS3.x
•MS-DOS4.x/4.0
•MS-DOS5.x
•MS-DOS6.x
•MS-DOS7/8

9. DOSCommandline:
DOSismainlyusedtheCommandlineDOSprovidesalotofofdifferentcommands
tomanagethecurrentoperatingsystemandtasks.YoucanlookfollowingCommand
lineoperations.
Multitasking
DOS(Diskoperatingsystem)providesmultitaskingfeatures.
Multitaskingmakesthemultipleprocesscanrunatthesmaetime.Thisisagreat
feature.Whichmeanswhiledownloadingafiles,listeningtomusicorwecanplay
games.
Multi-user
Multi-userfeaturesmakethesamecomputercanbeusedwithdifferentusernames
andsession.Alluser'sdataarestoredintheirprivatefoldersandtheiroperating
systemanddesktoprelatedsettingarestoredtoo.
Readmore:RunCMDCommandinPowerShell
AreDOScommandsstillused?
WhileDOSisseverelyoutdated,it'sstillusedinsomecapacity.Inevery
Windows-basedcomputer,there'saPowerShellorcommandprompttoday.It
allowsthemtousethesamecommandsasDOStoworkaroundtroublesor
solveissueswithhardware.
DOScommanddividedinto2parts:
1.InternalCommandsorMemory-ResidentCommands.
2.ExternalCommandorDisk-ResidenceCommands.
1.InternalCommand

10. Thesecommandsareautomaticallyloadedintothecomputer'smemoryduringthe
bootimgprocess.TheyactuallyincludedintheCommandsareexecutable
immediatlyaftergettingtheDOSprompt.
Afewinternalcommandsare:
VER CD..
VOL RD
DATE COPYCON
TIME TYPE
CLS COPY
DIR DEL
MD REN
CD PROMPT
VER
AllO/Shasitsowneditionnumberorrelaseorversionnumber.Theversionnumber
indicateswhicheditionofO/Sweareworkingon.
Syntax: VER
Example:VER
MicrosoftWindowsXP[version5.1.2600]
VOL
Itisusedtodisplayvolumelable(name)andserialnumberofthecurrentdrive.
Syntax: VOL[drive:]

11. Example: C:/>VOLD:
DATE
Usedtodisplaythecurrentsystemdateandpromptforenteringnewdate.
Syntax: DATE
Example: Date
TIME:
DisplaythecurrentsystemTimeandpromptforenteringnewtime.
Syntax: TIME
Example: Time
CLS:
Clearthescreen.
Syntax: CLS
Example: CLS
MDorMKDIR:
UsedtocreatanewDirectoryornestedDirectories.
Syntax: MD DIRECTORYNAME
MKDIRDIRECTORYNAME
Example: MDHARI<ENTER>

12. CD:
Thiscommandallowsustochangepresentdirectorytoanotherdirectory.
Syntex: CD[directoryname]
Example: CD Hari<Enter>
RD
Todeletetheemptydirectry.
Syntax: RD[directroyname]<Enter>
Example: RDHaripress<Enter>
NOTE:-
ThedirctroymuctbeemptywhenweuseRD
*Removewithsubdirectoriesandfiles.
Syntax: RD/S[directroyname]
Example: RD/sCOLOURpress<Enter>
COPYCON:
Weusethiscommandtocreateanewfile.
Syntax: COPYCON<FILENAME>
TherearetwonameinDOSandisdividedinto2parts.

13. 1.PrimaryName
2.Secondaryorextension.
1.PrimarynameisseparatedfromtheSecondarynaemextensionwiththehelpofa
dot(.)
Example: name.TXT
2.Secondarynameisoptional.TheextensiontellsDOSaboutwhatkindoffileitis.
AvalidCharacterfornamingafileare.fromAtoZandthedigit0to9
Example: CopyConname.text
Note:-Typinghareandwhenwearedone,pressCtr+ZorF6keyfollowedbyEnter
tosavethecurrentdocument.
TYPE:
Thiscommandallowedallowsustoseetheconttentsofanexistingfileonthe
screen.
Syntax: TYPE<FileName>
Example: TYPEname.text
COPY:
WecanUsecopycommandintwoways:-
FiletoFileCopyUsingthiscommandoverrideonefileofanexistingfilefromone
locationtoanotherfile.

14. Syntax: COPY[SOURCEFILENAME] [TARGARFILE
NAME]
Example: COPYname.txtname.text
FiletoFileDirectory
Thisisusetoduplicatefilesofanexistingfileonedirectorytoanotherwithdifferent
nameorexitingname.
Syntex: COPY[SOURCEFILENAME] [TARGET
DirectoryName]
DEL/ERASE
Thiscommandremovesoneormorefilesfromthediskorcurrentworkingdirectorys.
Syntax: DEL[FileName]orERASE [FileName]
Example: DELHari.txtorERASE Krishna.Txt
REN
Usedtochangethenameofthefileordirectory.
RenameDirectory
Syntax: Ren[olddirectoryname]
[newdirectoryname]
RenameFile
Syntax: REN<oldfilename.Extension> <Newfilename.
Extension>
Example: RENname.text name1.doc

15. DIR:
Thiscommanddisplaythelistofdirectoryandfileswithdetailslikedateofcreation
whetheritisdirectoryorfileetc.
Syntax: DIR<ENTER>
DIRCommandwithSwithes:
DIR/OD Datewise.
DIR/ON Alphabetical.
DIR/OE Extensionwise.
DIR/L Fileanddirectoryin lowercase
letters.
DIR/S ToseeSubdirectory.
DIR/P ToSeeUsingPause
(LikemoreCommand).
DIR/AH Toseehiddenfile.
DIR/W Displayonlycolumn
offilenamesand
directories.

16. DIR/B Displaysonlyfileor directory.
"?"And"*" Wildcardcharacter.
DIR? Displaydirectoryof latteras
many?mark thosemanydirectory.
DIR*.txt Displayallthefiles with
extension.txt
PROMPPT:
Thiscommandallowsustocustomozethedosprompt.
Syntax:PROMPT$Switches
Example:PROMPT$P$G<Enter>
TREE:
Itisusedtodisplaydirectorystructureofaspecifieddirectorygraphcally.
Syntax:TREE<DirectoryName>
TREE/F:
Itisusedtodisplaythenamesofthefileineachdirectory.
Syntax:TREE/F<DirectoryName>
2.EXTERNALCOMMAND

17. ThesearealsocalledDisk-ResidentCommands.Thesecommandsaremeantfor
specialpurpose.ThesearefoundinSeparadefilesonHardDiskorFloppyDisk,So
thattheydon'ttypicallyconsumevaluablememoryonlyehencalled.
SomeExternalCommandsare:
MOVE
EDIT
MOVE:Thiscommandmove(cut)afileorgroupoffilsfromonedirectorytoanother
andalsoonedisktoanotherdisk.
Syntax:move<fileName><DirectoryName>
DownArrow:Showthenextcommandexecutedaftertheonethat'sbeing
displayed.
F7-Displaytheentirelistofcommandthatisexecuted.
F9-Selectcommands.
Alt+F7-Erasethecommandhistorylist.
Esc-Clearthecommandline.
WhereDopeopleUseDOS?
WindowsmighthavereplacedDOS,butsomepeoplestillpreferDOS.Herearethe
waysthatindustriesuseDISCoperatingsystemstoday.
1.LegacySystems:
Someprogramsandapplicationsthatcompanies,organizations,andgovernments
developedearlyweredesignedforDOS—basedcomputers.Restructuringthese

18. systemsrequirestimeandmoney.Thisstructureledtoorganizationsoperatingfor
DOSandhiringspecializedengineersforsupportandmaintenance.
2.EmbeddedSystems:
Duetotheirsimpletasks,DOSisstillusesinsomeembeddedsystems(e.g.,ATMs,
medicalequipment,publicspaceKiosks,andstorespoint—of—sallterminals).
3.VintagecomputingandretroGaming:
CollectorsandhobbyistshavepreservedtheirDOSComputersfromdecadesago.
Torunclassicsoftwareonupdatecomputer,DOSemulatorsandvirtualmachines
arededicatedtothecommunityofnostalgicandretrogamers.
4.Nostalgiaandlearning:
Understandinghowpre—GUIcomputersworkisthefirststeptolearningabout
programming.DOSdoesthisbyexposingtechenthusiastsandstudentstotheearly
daysofcomputing.StudentscaneasilyexperimentwithDOSwithlow—level
programmingbeforetryingtoday'smorecomplexoperatingsystems.
Readmore:TaskManagerChromebook:ADeepDive
DOSHardwareSupport:
DOSOperatingsystemismainlydevelopedforpersonalcomputersorPCs.Thefirst
PCisdesignedtouseIntel808616bitprocessor.DOSisdevelopedforIBMby
MicrosoftandaeveryidenticaloperatingsystemnamedMS—DOSatthetimepc
developeddiffrentHardwareissupportedbytheDOSoperatingsystemlike
Commodore64,Atari800,Apple11,etc.
Advantages
•ThecommandsinDOSareeasytorememberanduse.
•DOSisfreeofcostandcanbeinstalledeasily.

19. •ItgivesusdirectaccesstotheBIOScalls.
•Itcanrunonsmallermachinesandthereforethebootingprocessismuch
fasterthanotheroperatingsystems.
•DOSisverylightweightanditallowsaccesstohardware.
•Itdoesnothavetheoverheadofamultitaskingoperatingsystem.
Disadvantages
•DOSdoesn’tsupportmultitasking.
•Itonlyhas2GBofspacewhichcannotbeextended.
•Itcanonlyhaveasingleuseratatime.
•Itisnotcompatiblewithotherbrowsers.
•Itdoesn’tsupportnetworking.
•AutomaticIRQorderingisnotsupportedbytheOS.
•Notnearlyasfancyinthegraphicsdepartment.
ThereabasicflowofDOSCommandwork:
1.Bootprocess:
DOSundergoesabootprocesswhenthecomputerturnson.BIOS(Doscomponent)
initiallychecksifthedeviceworkproperly.
2.DOSkernel:
AftertheBIOSperformsaself—check,theDOSkerneltaskscontrol.
Thisiswhentheactualoperationofthecomputerbegins.Thekernelalsomanages
memory,operatingfilesetc.
3.CommandPrompt:

20. Whenthekerneltasksover,it'stimefortheusertoenterCommands.Command
PromptareIntroductionyouthecomputertoperform.
4.CommandExecution:
Commandexecutionhappenswhenthekernelreadsandinterpretsthecommand
intoactions.
5.Filesystem:
ThoughtDOS,thecomputercanstorethedatayouperformthoughtdirectories.
6.RunningApplications:
Appshavetheirownsetofcommandsbuiltintothem.Whentheuserpromptsthe
computertorunaapp,theapptemporarilytakesover.
7.ExitingDOS:
Afterperformingthetask,theuserwillshutthecomputerdown,
automaticallybringingDOSintoBIOSmode.
Inconclusion,DOS,withitsintricatefunctionsandnuancedsimplicity,
representsacaptivatingenigmawithintheworldoftechnology.Itremindsus
thatwithintheseeminglystraightforwardliesthepotentialforboundless
complexity,andwithintheuniformityofcoderesidesthesparkofcreativityand
innovation.
Thanksforreading.
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