A practical file for computer applications

1. STANI MEMORIAL P.G. COLLEGE
PRACTICAL FILE
Elementary Computer Application
Submitted By: jaikishan godara Submitted To:

2. S.NO
.
TOPIC DATE ______
______
___
1 The architecture of computer
system
20th Jan
2 Hardware and software
20th Jan
3 Input and output devices 20th Jan
4 Computer memory 20th Jan
5 Mail Merge 20th Jan
6 Four function are explained 20th Jan
7 Spread sheet 20th Jan
8 M-commerce 20th Jan
9 History of internet 20th Jan
10 Eight function are explained 20th Jan
11 Thirty-five short keys are written 20th Jan
12 Computer network 20th Jan

3. 1. Explain the architecture of a computer system?
Answer1.A computersystemisbasicallyamachinethat simplifiescomplicatedtasks. Itshouldmaximizeperformanceand reducecosts
aswellaspower consumption.ThedifferentcomponentsintheComputerSystemArchitectureareInputUnit,Output Unit,StorageUnit,
ArithmeticLogicUnit,ControlUnit,etc.
Adiagram that showstheflowofdata betweentheseunits isas follows −

4. THEINPUTDATATRAVELSFROMTHEINPUTUNITTOALU.SIMILARLY,THECOMPUTEDDATATRAVELSFROMALU
TOTHEOUTPUTUNIT.THEDATACONSTANTLYMOVESFROMTHESTORAGEUNITTOALUANDBACKAGAIN.THISIS
BECAUSESTOREDDATAISCOMPUTEDBEFOREBEINGSTOREDAGAIN.THECONTROLUNITCONTROLSALLTHE
OTHERUNITSASWELLASTHEIRDATA.
DETAILSABOUTALLTHECOMPUTERUNITSARE−
•INPUTUNIT:
THEINPUTUNITPROVIDESDATATOTHECOMPUTERSYSTEMFROMTHEOUTSIDE.SO,BASICALLY,ITLINKSTHE
EXTERNALENVIRONMENTWITHTHECOMPUTER.ITTAKESDATAFROMTHEINPUTDEVICES,CONVERTSITINTO
MACHINELANGUAGE,ANDLOADSITINTOTHECOMPUTERSYSTEM.KEYBOARD,MOUSE,ETC.ARETHEMOST
COMMONLYUSEDINPUTDEVICES.
•OUTPUTUNIT:
THEOUTPUTUNITPROVIDESTHERESULTSOFTHECOMPUTERPROCESSTOTHEUSERSI.E.ITLINKSTHE
COMPUTERWITHTHEEXTERNALENVIRONMENT.MOSTOFTHEOUTPUTDATAISINTHEFORMOFAUDIOORVIDEO.
THEDIFFERENTOUTPUTDEVICESAREMONITORS,PRINTERS,SPEAKERS,HEADPHONES,ETC.

5. •StorageUnit:
Storageunitcontainsmanycomputercomponentsthatareusedtostore data.Itistraditionallydividedinto
primarystorageandsecondarystorage.Primarystorageisalsoknownasthemainmemoryandisthe
memorydirectlyaccessiblebytheCPU.SecondaryorexternalstorageisnotdirectlyaccessiblebytheCPU.
Thedatafromsecondarystorageneeds tobebroughtintotheprimarystoragebefore theCPUcanuseit.
Secondarystoragecontainsalargeamountofdatapermanently.
•ArithmeticLogic:
UnitAllthecalculationsrelatedtothecomputersystemareperformedbythearithmeticlogicunit.Itcan
performoperationslikeaddition,subtraction,multiplication,division,etc.Thecontrolunittransfersdatafrom
storageunittoarithmeticlogicunitwhencalculationsneedtobeperformed.Thearithmeticlogicunitandthe
controlunittogetherformthecentralprocessingunit.
•ControlUnit:
Thisunitcontrolsalltheotherunitsofthecomputersystemandsoisknownasitscentralnervoussystem.It
transfers datathroughoutthecomputerasrequiredincludingfromthestorageunittothecentralprocessing
unitandviceversa.Thecontrolunitalsodictateshowthememory,input-outputdevices,arithmeticlogicunit,
etc.shouldbehave.

6. 2. What do you mean by hardware and software? Write down the types of computer
software?
Answer2.ComputerHardware:
Hardwarerefers tothephysicalcomponentsof acomputer.ComputerHardwareisanypartofthe
computerthatwecantouchtheseparts.Thesearetheprimaryelectronicdevicesusedtobuildupthe
computer.ExamplesofhardwareinacomputeraretheProcessor, MemoryDevices,Monitor,Printer,
Keyboard,Mouse,andtheCentralProcessingUnit.
ComputerSoftware:
Softwareisacollectionofinstructions,procedures,documentationthatperforms different tasksona
computersystem.wecansayalsoComputerSoftwareisaprogrammingcodeexecutedonacomputer
processor. Thecodecanbemachine-levelcodeorthecodewrittenforanoperatingsystem.Examples
ofsoftware areMsWord,Excel,PowerPoint,GoogleChrome,Photoshop,MySQLetc.

7. Types of computer software:

8. 3. Explain different input and output devices?
Answer3.InputDevices:
Adevicethat canbeusedto insertdata into acomputersystemiscalledas inputdevice.Itallowspeopleto supply
informationtocomputerswithout anyinputdevices,acomputerwouldonlybeadisplaydeviceandnotallowusersto
interactwithit, Examplesofinputdevicesincludekeyboards, mouse,scanners,digital camerasandLight pen,joysticks,
Touch-screen,OMR,OBR,OCR.
Keyboard:Most commonand verypopular input deviceis keyboard. Thekeyboardhelpsininputting thedata to the
computer.Thelayoutofthekeyboardislikethatoftraditional typewriter, althoughtherearesomeadditional keys
providedforperformingsomeadditional functions.

9. Mouse:
MouseismostpopularPointingdevice.Itisaveryfamouscursor-
controldevice.Itisasmallpalmsizeboxwithagroundballatitsbase
whichsenses themovementofmouseandsendscorrespondingsignals
toCPUonpressingthebuttons.
Generally,ithastwobuttonscalledleftandrightbuttonandscrollbaris
present atthemid.Mousecanbeusedtocontroltheposition ofcursoron
screen,butitcannotbeusedtoentertextintothecomputer.
Advantages
•Easytouse•Notveryexpensive•Movesthecursorfaster thanthearrowkeys
ofkeyboard.
Scanner:
Scannerisaninputdevicewhichworksmorelikeaphotocopymachine.Itis
usedwhensomeinformationisavailableonapaperanditistobetransferred
totheharddiscof thecomputerforfurthermanipulation.Scannercaptures
imagesfromthesourcewhicharethenconvertedintothedigitalformthatcan
bestoredon thedisc.Theseimagescanbeeditedbefore theyareprinted.

10. Joystick:
Joystickisalsoapointingdevicewhichisusedtomovecursorposition
onamonitorscreen.Itisastickhavingasphericalballatitsbothlower
andupperends.Thelowersphericalballmovesinasocket.The
Joystickcanbemovedinallfourdirections.
Thefunctionofjoystickissimilartothatof amouse.Itismainlyusedin
ComputerAidedDesigning (CAD)andplayingcomputergames.

11. MagneticInkCardReader(MICR)MICRinputdeviceisgenerallyusedinbanksbecauseofalargenumber
ofchequestobeprocessed everyday.Thebank’scodenumberandchequenumberareprintedonthe
chequeswithaspecialtypeofinkthatcontainsparticlesofmagneticmaterialthataremachinereadable.
ThisreadingprocessiscalledMagneticInkCharacterRecognition(MICR).ThemainadvantageofMICRis
thatitisfastandlesserror prone.
OpticalCharacterReader(OCR):
OCRisaninputdeviceusedtoreadaprintedtext.OCRscanstextopticallycharacterbycharacter,
convertsthemintoamachine-readablecodeandstores thetextonthesystemmemory.
BarCodeReaders:
BarCodeReaderisadeviceusedforreadingbarcodeddata(datainformoflightanddarklines).
Barcodeddataisgenerallyusedinlabellinggoods,numberingthebooksetc.Itmaybeahand-held
scannerormaybeembeddedinastationaryscanner.

12. OpticalMarkReader(OMR):
OMRisaspecialtypeofopticalscannerusedtorecognizethetypeof
markmadebypenorpencil.Itisusedwhereoneoutofafew
alternativesistobeselectedandmarked.Itisspeciallyusedfor
checkingtheanswersheets ofexaminationshavingmultiplechoice
questions.
Touchscreen:
Touchscreenisaninputdevice.Touchscreentechnologyisthedirect
manipulationtypegesture-basedtechnology.Directmanipulationis
theabilitytomanipulatedigitalworldinsideascreenwithouttheuseof
command-linecommands.
AdevicewhichworksontouchscreentechnologyiscoinedasTouch
screen.Atouchscreenisanelectronicvisualdisplaycapableof
‘detecting’andeffectively ‘locating’atouchoveritsdisplayarea.

13. OutputDevices:
Adevicewhichisusedtodisplayresultfromacomputeriscalledas
outputdevice.ItAllowspeopletoreceiveinformationfromcomputers.
Anoutputdeviceisanyperipheralthatreceives ordisplaysoutput
fromacomputer.Thepictureshowsaninkjetprinter,anoutputdevice
thatcanmakeahardcopyofanythingbeingdisplayedonamonitor.
Outputdeviceiselectronicequipmentconnectedtoacomputerand
usedtotransferdataoutofthecomputerintheformoftext,images,
soundsorprint.Examplesofoutputdevicesinclude:Digitizers,Plotters,
LCD,PlasmaDisplay,Printers,etc.
Digitizer:
Digitizerisaninputdevicewhichconvertsanaloginformationintoa
digitalform.Digitizercanconvertasignalfromthetelevision camera
intoaseries of numbersthatcouldbestoredinacomputer.Theycanbe
usedbythecomputertocreateapictureof whateverthecamerahad
beenpointedat

14. Plotters:
Aplotterisaprinterthatinterprets commandsfromacomputerto
makelinedrawingsonpaperwithoneormoreautomatedpens.Unlike
aregularprinter,theplottercandrawcontinuouspoint-to-pointlines
directlyfromvectorgraphicsfilesorcommands.
Thereareanumberof different typesofplotters:adrumplotterdraws
onpaperwrappedaroundadrumwhichturnstoproduceonedirection
oftheplot,whilethepensmovetoprovidetheotherdirection;aflatbed
plotterdrawsonpaperplacedonaflatsurface;andanelectrostatic
plotterdrawsonnegativelychargedpaperwithpositively charged
toner.
Plotterswerethefirsttypeofprinterthatcouldprintwithcolorand
rendergraphicsandfull-sizeengineeringdrawings.Asarule,plotters
aremuchmoreexpensivethanprinters.Theyaremostfrequentlyused
forCAE(computeraidedengineering)applications,suchasCAD
(computer-aideddesign)andCAM(computer-aidedmanufacturing).

15. Monitors:
MonitorcommonlycalledasVisualDisplayUnit(VDU)isthemainoutput
deviceofacomputer.Itformsimagesfromtinydots,calledpixelsthat
arearrangedinarectangularform.Thesharpnessoftheimage
dependsupontheno.ofthepixels.Therearetwokindsofviewing
screenusedfor monitors.
•Cathode-RayTube(CRT)
•LiquidCristalDisplay(LCD)
•PlasmaDisplay

16. Printers:
Printeristhemostimportantoutputdevice,whichisusedtoprint
informationonpaper.
Therearetwotypesofprinters
•ImpactPrinters•Non-ImpactPrintersImpactPrintersTheprinters
thatprintthecharactersbystrikingagainsttheribbonandontothe
paperarecalledimpactprinters.CharacteristicsofImpactPrintersare
following
•Verylowconsumablecosts
•Impactprintersareverynoisy
•Usefulforbulkprintingduetolowcost
•Thereisphysicalcontactwiththepapertoproduceanimage
Theseprintersareoftwotypes
•Characterprinters•LineprintersCharacterPrinters:Character
Printersareprinterswhichprintonecharacteratatime.
Theseareoffurthertwotypes
•DotMatrixPrinter(DMP)•DaisyWheel

17. 4. What do you understand by computer memory? Explain
types of memory in computer?
Answer4. Computermemoryisagenerictermfor allof thedifferent typesofdatastoragetechnology
thatacomputermayuse,includingRAM,ROM,andflashmemory.
Thekeydifference between primaryandsecondarymemoryisspeedofaccess.
•PrimarymemoryincludesROMandRAM,andislocatedclosetotheCPUonthecomputermotherboard,
enablingtheCPUtoreaddatafromprimarymemoryveryquicklyindeed.Itisusedtostore datathatthe
CPUneedsimminentlysothatitdoes nothavetowaitforittobedelivered.
•Secondarymemorybycontrast,isusuallyphysicallylocatedwithinaseparatestoragedevice,suchas
aharddiskdriveorsolid-statedrive(SSD),whichisconnectedtothecomputersystemeitherdirectly
oroveranetwork.Thecostpergigabyteof secondarymemoryismuchlower,butthereadandwrite
speedsaresignificantlyslower.

18. Overseveralperiodsofcomputerevolution,awideof
arrayofcomputermemorytypeshasbeendeployed,
eachwithitsownstrengthsandweaknesses.
PrimaryMemoryTypes:RAMandROMTherearetwo
keytypesofprimarymemory:
1.RAM,orrandom-accessmemory
2.ROM,orread-onlymemoryLet’slookin-depthat
bothtypesofmemory.

19. 1) RAM
ComputerMemoryTheacronymRAMstemsfromthefactthatdatastoredinrandomaccessmemorycanbeaccessed –
asthenamesuggests–inanyrandomorder.Or,putanotherway,anyrandombitofdatacanbeaccessedjustas
quicklyasanyotherbit.
ThemostimportantthingstounderstandaboutRAMarethatRAMmemoryisveryfast,itcanbewrittentoaswellas
read,itisvolatile(soalldatastoredinRAMmemoryislostwhenitloses power)and,finally,itisveryexpensive
comparedtoalltypesofsecondarymemoryintermsofcostpergigabyte.
ItisbecauseoftherelativehighcostofRAMcomparedtosecondarymemorytypesthatmostcomputersystemsuse
bothprimaryandsecondarymemory.DatathatisrequiredforimminentprocessingismovedtoRAMwhereitcanbe
accessedandmodifiedveryquickly,sothattheCPUisnotkeptwaiting.
Whenthedataisnolongerrequireditisshuntedouttoslowerbutcheapersecondarymemory,andtheRAMspacethat
hasbeenfreedupisfilledwiththenextchunkofdatathatisabouttobeused.

20. Typesof RAM•
DRAM:DRAMstandsforDynamicRAM,anditisthemostcommontypeofRAMusedincomputers.Theoldest
typeisknownassingledatarate(SDR)DRAM,butnewercomputersusefaster dualdatarate(DDR)DRAM.
DDRcomesinseveralversionsincludingDDR2,DDR3,andDDR4,whichoffer betterperformanceandare
moreenergy efficient thanDDR.Howeverdifferent versions areincompatible,soitisnotpossible tomix
DDR2withDDR3DRAMinacomputersystem.
DRAMconsists ofatransistorandacapacitorineachcell.
•SRAM:SRAMstandsforStaticRAM,anditisaparticulartypeofRAMwhichisfasterthanDRAM,butmore
expensiveandbulker,havingsixtransistorsineachcell.Forthosereasons SRAMisgenerallyonlyusedas
adatacachewithinaCPUitself orasRAMinveryhigh-endserversystems.AsmallSRAMcacheof themost
imminently-neededdatacanresultinsignificantspeedimprovementsinasystemThekeydifferences
betweenDRAMandSRAMisthatSRAMisfasterthanDRAM –perhapstwotothreetimesfaster–butmore
expensiveandbulkier.SRAMisusuallyavailableinmegabytes,whileDRAMispurchasedingigabytes.
DRAMuses moreenergythanSRAMbecauseitconstantlyneedstoberefreshed tomaintaindataintegrity,
whileSRAM–thoughvolatile–doesnotneedconstantrefreshing whenitispoweredup.

21. 2)ROM:
ComputerMemoryROMstandsfor read-onlymemory,andthenamestemsfromthefactthatwhiledata
canbereadfromthistypeof computermemory,datacannotnormallybewrittentoit.
ItisaveryfasttypeofcomputermemorywhichisusuallyinstalledclosetotheCPUonthemotherboard.
ROMisatypeofnon-volatilememory,whichmeansthatthedatastoredinROMpersists inthememory
even whenitreceivesnopower–forexamplewhenthecomputeristurnedoff.Inthatsenseitissimilar
tosecondarymemory,whichisusedfor longtermstorage.
Whenacomputeristurnedon,theCPUcanbeginreadinginformationstoredinROMwithouttheneedfor
driversorothercomplexsoftwaretohelpitcommunicate.TheROMusuallycontains“bootstrapcode”
whichisthebasicsetof instructionsacomputerneedstocarryouttobecomeawareoftheoperating
systemstoredinsecondarymemory,andtoloadpartsoftheoperatingsystemintoprimarymemoryso
thatitcanstartupandbecomereadytouse.
ROMisalsousedinsimplerelectronicdevicestostorefirmwarewhichrunsassoon asthedeviceis
switchedon.

22. Typesof ROM:
ROMisavailableinseveraldifferent types,includingPROM,EPROM,andEEPROM.
•PROM
PROMstandsfor ProgrammableRead-OnlyMemory,anditisdifferent fromtrueROMinthatwhilea
ROMisprogrammed(i.e.hasdatawrittentoit)duringthemanufacturingprocess,aPROMis
manufacturedinanemptystateandthenprogrammedlaterusingaPROMprogrammerorburner.
•EPROM
EPROMstandsforErasableProgrammableRead-OnlyMemory,andasthenamesuggests,datastoredin
anEPROMcanbeerasedandtheEPROMreprogrammed.ErasinganEPROMinvolvesremovingitfrom
thecomputerandexposingittoultravioletlightbefore re-burningit.
•EEPROM
EEPROMstandsfor ElectricallyErasableProgrammableRead-OnlyMemory,andthedistinctionbetween
EPROMandEEPROMisthatthelattercanbeerasedandwrittentobythecomputersystemitisinstalled
in.Inthatsense EEPROMisnotstrictlyread-only.
However,inmanycasesthewriteprocessis slow,soitisnormallyonlydonetoupdateprogramcode
suchasfirmwareorBIOScodeonanoccasionalbasis

23. SecondaryMemoryTypes
Secondarymemorycomprisesmanydifferentstorage mediawhichcanbedirectly
attachedto a computersystem.
Theseinclude:
•harddisk drives
•solidstate drives (SSDs)
•Optical(CDorDVD)drives
•TapedrivesDifferencesbetweenRAMand ROM
ROM:
•Non-volatile
•Fastto read
•Usuallyused insmallquantities
•Cannotbewritten to quickly
•Usedto storeboot instructionsorfirmware
•Relativelyexpensivepermegabyte storedcomparedto RAM
RAM: •Volatile• Fastto readandwrite•Usedas systemmemoryto storedata
(includingprogramcode)that theCPUneedsto processimminently•Relativelycheap
permegabyte storedcomparedto ROM,but relativelyexpensivecomparedto
secondarymemory

24. Answer5.Mailmergeisa MicrosoftWordfeatureoftenused toproducea numberofsimilardocuments,includingelements
froma separatedata document(e.g.adatabase, spreadsheetorOutlookcontactsfile).
Thelistiscombinedwith standard text,usually toproducea letterorinvitetoa seriesofdifferentrecipients.
Therearefivestepsto themailmergeprocess:
1. Chooseyour documenttype -Withinthemailingstabclickthestart mailmergebutton andadropdown willappear. You
canchoosefromlabels,envelopes,emails,lettersora directory.
2. 2.Selectyour recipients-Hereyou canchooseto"typea newlist"whereyou entertherecipientsintoadatabase oneby
one,"useanexistinglist"suchas aspreadsheetto importthedata or"selectfromyour Outlook contacts".You canthenedit
therecipientdata shouldyou wish.
3. 3.Write&insertfields-Nowthatyour documentislinkedto your recipientdata you canaddtheindividual personalization
fields.Thisincludesaddress fields(usethe"address block"button) andgreetingline(e.g.dearSirorMadam, recipient's
firstnameetc).
4.
5. 4.Previewresults -Checkthat thefieldsyou've insertedarepullingthecorrectdata through(e.g.thetown fieldisn't
pullingthroughthecountyinformation)andpositioned correctlyonyour document.
6. 5.Finish&merge-Now that you'rehappywith your content,andthecorrectdata fieldsarebeingimported, you canfinish
andmergethedocumentandyour data to createthefinalproduct. Therearethreeoptions here:
5.Whatismailmerge?Explainstepsformailmerge?

25. 6. Explain the following:
a. Page Layout :
: ThePageLayout Tabholdsalltheoptions that allowyouto arrangeyour documentpages justthewayyou wantthem.You cansetmargins,apply
themes,controlofpage orientation and size,add sectionsandlinebreaks, displaylinenumbers,andsetparagraph indentation andlines.
b. Header and footer:
Theheaderisa sectionofthedocumentthat appears inthetop margin, whilethefooteris asectionofthedocumentthat appears inthebottom
margin.Headersandfootersgenerallycontainadditional information suchaspage numbers,dates, anauthor's name,andfootnotes,whichcanhelp
keeplongerdocumentsorganizedandmakethemeasiertoread.Textenteredintheheaderorfooterwillappear oneachpage ofthedocument.
c. Slide Show:
APowerPointslideshow(PPT)isapresentation createdonsoftware fromMicrosoft that allowsusersto addaudio, visual and audio/visual featuresto
apresentation.Itisconsideredto bea multimediatechnologyandalsoactsasatool forcollaboration andcontentsharing. PowerPointis includedin
MicrosoftOffice,makingitoneofthemostwell-knownand widelyused brandsofpresentation software. APowerPointslideshowisalsoknownasa
PowerPointpresentation.
d. Macro:
Amacroisanautomated inputsequencethat imitates keystrokes ormouseactions.A macroistypicallyusedtoreplacea repetitiveseriesof
keyboard andmouseactions andusedofteninspreadsheetsandwordprocessingapplications likeMSExcelandMSWord.Thefileextensionofa
macrois commonly.MAC.Theconceptofmacrosisalsowell-knownamongMMORPG gamers(Massively Multiplayer OnlineRole-PlayingGames) and
SEO(SearchEngineOptimization) specialists.Intheworldofprogramming, macrosareprogrammingscriptsusedbydevelopers to re-usecode.The
termmacrostands for“macro-instruction”(longinstruction).

26. 7. What is a spread sheet? Explain cell referencing in MS Excel?
Answer.
Spreadsheet:
Aspreadsheetisasoftwareprogramyouusetoeasilyperformmathematicalcalculationson
statisticaldataandtotallinglongcolumnsofnumbersordeterminingpercentagesand
averages.
Cellreferences:
Acellreference, alsoknownasacelladdress,isamechanismthatdefines acellona
worksheetbycombiningacolumnletterandarownumber.Wecanrefer toanycell(inExcel
formulas)intheworksheetbyusingthecellreferences.
Typesof CellReference inExcelWehavethreedifferent typesof CellReferences inExcel–
1. RelativeCellReference inExcel
2. 2.AbsoluteCellReference inExcel
3. 3.MixedCellReference inExcel

27. 8. What is M-Commerce?
Answer 8:
M-commerceistheuseof handheld,wireless gadgetssuchasmobile
phones,tabletsandpersonal digitalassistantstoperformonline
commercialtransactions.
It'sacomponentofelectroniccommercethatworksonmobiledevices.
M-commerceenablesabusiness toreachmorecustomersonline.
Italsoprovidescustomerswithawiderangeofproductchoicesand
paymentoptionsfromdifferent vendors.

28. 9. Write down the history of Internet?
Answer9:
TheInternetstartedoff withresearch intowhatwasthenknownaspacketswitchingasearlyasthe1960s.Packetswitchingwasthoughtof
abetterandfaster methodtotransferdatathanthehardwaresolutiontotheproblem,i.e.,thecircuitry.Thepacketswitchingtechnology
wasessential tothedevelopmentofARPANETbytheUnitedStatesMilitary.
ARPANETisconsideredthefirstknowngroupofinterconnectedcomputersakatheinternet.Thissystemwasusedtotransferconfidential
databetween theMilitary.ThisdatasharingtechnologywasthenopenedtoeducationalinstitutesintheUnitedStatestoallowthemto
accesstothegovernment’ssupercomputer,firstat56Kbit/s,thenat1.5Mbit/s,andthenat45Mbit/s.ComInternetservice providersbegan
toariseinthelate1980sandtheinternetwasfullycommercializedintheUSby1995.

29. 10.Explain the following:
a. Firewall:
Firewallscanbeviewedasgatedbordersorgatewaysthatmanagethetravelof permittedandprohibitedwebactivityina
privatenetwork.Thetermcomesfromtheconceptof physicalwallsbeingbarrierstoslowthespreadoffire untilemergency
services canextinguish it.Comparably,networksecurityfirewallsareforwebtrafficmanagement—typicallyintendedto
slowthespreadof webthreats.
b. Security threats:
Cybersecurityprofessionals shouldhaveanin-depthunderstandingofthefollowingtypesofcybersecuritythreats.
1. Malware:
Malwareismalicioussoftware suchasspyware,ransomware,virusesandworms.Malwareisactivatedwhenauserclickson
amaliciouslinkorattachment,whichleadstoinstallingdangeroussoftware.Ciscoreportsthatmalware,onceactivated,can:
•Blockaccesstokeynetworkcomponents(ransomware)
•Installadditionalharmfulsoftware
•Covertlyobtaininformationbytransmittingdatafromtheharddrive(spyware)
•Disruptindividualparts,makingthesysteminoperable

30. 2.Emotet:
TheCybersecurityandInfrastructureSecurityAgency(CISA)describes Emotetas“anadvanced,modularbankingTrojanthat
primarilyfunctionsasadownloaderordropperof otherbankingTrojans.Emotetcontinuestobeamongthemostcostlyand
destructivemalware.”
3.Denialof Service:
Adenialof service(DoS)isatypeofcyber-attackthatfloodsacomputerornetworksoitcan’trespondtorequests.AdistributedDoS
(DDoS)doesthesamething,buttheattackoriginatesfromacomputernetwork.Cyberattackersoften useafloodattacktodisruptthe
“handshake”processandcarryoutaDoS.Severalothertechniquesmaybeused,andsomecyberattackersusethetimethata
networkisdisabledtolaunchotherattacks.AbotnetisatypeofDDoSinwhichmillionsofsystemscanbeinfectedwithmalwareand
controlledbyahacker,accordingtoJeff Melnickof Netwrix,aninformationtechnologysecuritysoftwarecompany.Botnets,
sometimescalledzombiesystems,targetandoverwhelmatarget’sprocessingcapabilities.Botnetsareindifferent geographic
locationsandhardtotrace.
4.ManintheMiddle:
Aman-in-the-middle(MITM)attackoccurswhenhackersinsertthemselvesintoatwo-partytransaction.Afterinterruptingthe
traffic,theycanfilterandstealdata,accordingtoCisco.MITMattacksoften occurwhenavisitorusesanunsecuredpublicWi-Fi
network.Attackersinsertthemselvesbetween thevisitorandthenetwork,andthenusemalwaretoinstallsoftware andusedata
maliciously.

31. 5.Phishing:
Phishingattacksusefakecommunication,suchasanemail,totrickthereceiverintoopeningitandcarryingout
theinstructionsinside, suchasprovidingacreditcardnumber.“Thegoalistostealsensitive datalikecreditcard
andlogininformationortoinstallmalwareonthevictim’smachine,”Ciscoreports.
6.SQLInjection:
AStructuredQueryLanguage(SQL)injectionisatypeofcyber-attackthatresultsfrominsertingmaliciouscode
intoaserverthatuses SQL.Wheninfected,theserverreleases information.Submittingthemaliciouscodecanbe
assimpleasenteringitintoavulnerablewebsite searchbox.
7.Password:
AttacksWiththerightpassword,acyberattackerhasaccesstoawealthofinformation.Socialengineeringisa
typeof passwordattackthatDataInsiderdefines as“astrategycyberattackerusethatrelies heavilyonhuman
interactionandoften involvestrickingpeopleintobreakingstandardsecuritypractices.”Othertypesofpassword
attacksincludeaccessingapassworddatabaseoroutrightguessing.

32. 3.CyberLawandCyberSecurity:
Cybersecuritydenotes thetechnologiesandproceduresintendedtosafeguard
computers,networks,anddatafromunlawfuladmittance,weaknesses, andattacks
transportedthroughtheInternetbycyberdelinquents.ISO27001(ISO27001)isthe
internationalCybersecurityStandardthatdeliversamodelfor creating,applying,
functioning,monitoring,reviewing,preserving,andimprovinganInformationSecurity
ManagementSystem.
TheMinistryofCommunicationandInformationTechnologyunderthegovernmentof
IndiaprovidesastrategyoutlinecalledtheNationalCybersecurityPolicy.
Thepurposeofthisgovernmentbodyistoprotectthepublicandprivateinfrastructure
fromcyber-attacks.TheInformationTechnologyAct2000oranylegislationinthe
CountrydoesnotdescribeormentionthetermCyberCrime.Itcanbeglobally
consideredasthegloomierfaceof technology.
Theonlydifference betweenatraditionalcrimeandacyber-crimeisthatthecyber-
crimeinvolvesinacrimerelatedtocomputers.

33. 4.Piracy:
Piracyrefers totheunauthorizedduplicationof copyrightedcontentthatis
thensoldatsubstantiallylowerpricesinthe'grey'market.Theeaseof
accesstotechnologyhasmeantthatovertheyears,piracyhasbecomemore
rampant.Forexample,CDwritersareavailableoff theshelfatverylow
prices,makingmusicpiracyasimpleaffair.
Copyright:
Copyrightisatypeofintellectualpropertythatprotectsoriginalworksof
authorshipassoon asanauthorfixes theworkinatangibleformof
expression. Incopyrightlaw,therearealotofdifferent typesofworks,
includingpaintings,photographs,illustrations,musicalcompositions,sound
recordings,computerprograms,books,poems,blogposts,movies,
architecturalworks,plays,andsomuchmore!
OpenSource:
Thetermopen sourcerefers tosomethingpeoplecanmodifyandshare
becauseitsdesignispubliclyaccessible.Exampleof opensourcesoftware
areLinux,Androidetc.

34. 11. Write down the shortcut keys for the following purposes:
I. New Document = Ctrl + N
II. Open a document = Ctrl + O
III. Save a document = Ctrl + S
IV. Save as a document = F12
V. Print a document = Ctrl + P
VI. New Slide = Ctrl + M
VII. Hyperlink = Ctrl + K
VIII. Superscript = Ctrl + Shift + +
IX. Subscript = Ctrl + =
X. Cut = Ctrl + X
XI. Copy = Ctrl + C
XII. Paste = Ctrl + V
XIII. Undo = Ctrl + Z
XIV. Redo = Ctrl + Y
XV. Increase font size =Ctrl+ Shift+>
XVI. Decrease font size =Ctrl + Shift+<
XVII.Underline = Ctrl+ U
XVIII.Bold = Ctrl + B

35. XIX.Italic=Ctrl+I
XX. Find=Ctrl+F
XXI.Replace=Ctrl+H
XXII.Selectall=Ctrl+A
XXIII.Closecurrentdocument=Ctrl+W
XXIV.SpellingandGrammarinWord=F7
XXV.Thesaurus=Shift+F7
XXVI.Help=F1
XXVII.LeftAlignment=Ctrl+L
XXVIII.RightAlignment=Ctrl+R
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36. 12.What do you mean by computer network?
Answer12. Acomputernetworkisagroupofcomputerslinkedtoeachotherthatenablesthecomputerto
communicatewithanothercomputerandsharetheirresources, data,andapplications.
Acomputernetworkcanbecategorizedbytheirsize.Acomputernetworkismainlyof fourtypes:

37. LAN(LocalAreaNetwork):
oLocalAreaNetworkisagroupofcomputersconnectedtoeachotherinasmallareasuchasbuilding,office. o
LANisusedfor connectingtwoormorepersonalcomputersthroughacommunicationmediumsuchastwisted
pair,coaxialcable,etc.oItislesscostlyasitisbuiltwithinexpensive hardwaresuchashubs,networkadapters,
andethernetcables.oThedataistransferred atanextremelyfasterrateinLocalAreaNetwork.oLocalArea
Networkprovideshighersecurity.

38. PAN(PersonalAreaNetwork):
oPersonalAreaNetworkisanetworkarrangedwithinanindividual
person,typicallywithinarangeof 10meters.
oPersonalAreaNetworkisusedforconnectingthecomputerdevices
ofpersonal useisknownasPersonalAreaNetwork.
oThomasZimmermanwasthefirstresearchscientist tobringtheidea
ofthePersonalAreaNetwork.oPersonalAreaNetworkcoversanarea
of30feet.
oPersonalcomputerdevicesthatareusedtodevelopthepersonal
areanetworkarethelaptop,mobilephones,mediaplayerandplay
stations.

39. TherearetwotypesofPersonal AreaNetwork:
oWiredPersonalAreaNetwork
oWireless PersonalAreaNetwork
Wireless PersonalAreaNetwork:
Wireless PersonalAreaNetworkisdevelopedbysimplyusingwireless technologiessuchasWIFI,Bluetooth.Itis
alowrangenetwork.WiredPersonal AreaNetwork:WiredPersonalAreaNetworkiscreatedbyusingtheUSB.
ExamplesofPersonal
AreaNetwork:
oBodyAreaNetwork:BodyAreaNetworkisanetworkthatmoveswithaperson.Forexample,amobilenetwork
moveswithaperson.Supposeaperson establishesanetworkconnectionandthencreatesaconnectionwith
anotherdevicetosharetheinformation.
oOffline Network:Anoffline networkcanbecreatedinsidethehome,soitisalsoknownasahomenetwork.A
homenetworkisdesignedtointegratethedevicessuchasprinters,computer,television buttheyarenot
connectedtotheinternet.
oSmallHomeOffice:Itisusedtoconnectavarietyofdevicestotheinternetandtoacorporatenetworkusinga
VPN

40. MAN(MetropolitanAreaNetwork)
oAmetropolitanareanetworkisanetworkthatcoversalarger
geographicareabyinterconnectingadifferent LANtoformalarger
network.
oGovernmentagenciesuseMANtoconnecttothecitizensandprivate
industries.
oInMAN,variousLANsareconnectedtoeachotherthroughatelephone
exchangeline.
oThemostwidelyusedprotocolsinMANareRS-232,FrameRelay,ATM,
ISDN,OC-3,ADSL,etc.
oIthasahigherrangethanLocalAreaNetwork(LAN)
UsesofMetropolitanAreaNetwork:
oMANisusedincommunicationbetween thebanksinacity.
oItcanbeusedinanAirlineReservation. oItcanbeusedinacollege
withinacity.
oItcanalsobeusedfor communicationinthemilitary

41. WAN(WideAreaNetwork):
oAWideAreaNetworkisanetworkthatextendsoveralarge
geographicalareasuchasstatesorcountries.
oAWideAreaNetworkisquitebiggernetworkthantheLAN.
oAWideAreaNetworkisnotlimitedtoasinglelocation,butitspans
overalargegeographicalareathroughatelephoneline,fibreoptic
cableorsatellitelinks.
oTheinternetisoneofthebiggestWANintheworld.oAWideArea
NetworkiswidelyusedinthefieldofBusiness,government,and
education.
ExamplesofWideAreaNetwork:
oMobileBroadband:
A4Gnetworkiswidelyusedacrossaregionorcountry.oLastmile:A
telecomcompanyisusedtoprovidetheinternetservices tothe
customersinhundredsofcitiesbyconnectingtheirhomewithfibre.
oPrivatenetwork:Abankprovidesaprivatenetworkthatconnectsthe
44offices. Thisnetworkismadebyusingthetelephoneleasedline
providedbythetelecomcompany.

42. Advantages of Wide Area Network:
Following are the advantages of the Wide Area Network:
o Geographical area: A Wide Area Network provides a large geographical area. Suppose if the
branch of our office is in a different city then we can connect with them through WAN. The
internet provides a leased line through which we can connect with another branch.
o Centralized data: In case of WAN network, data is centralized. Therefore, we do not need to
buy the emails, files or back up servers.
o Get updated files: Software companies work on the live server. Therefore, the programmers
get the updated files within seconds.
o Exchange messages: In a WAN network, messages are transmitted fast. The web
application like Facebook, WhatsApp, Skype allows you to communicate with friends.
o Sharing of software and resources: In WAN network, we can share the software and other
resources like a hard drive, RAM. o Global business: We can do the business over the internet
globally.
o High bandwidth: If we use the leased lines for our company then this gives the high
bandwidth. The high bandwidth increases the data transfer rate which in turn increases the
productivity of our company.

43. Disadvantages of Wide Area Network:
The following are the disadvantages of the Wide Area
Network:
o Security issue: A WAN network has more security issues as
compared to LAN and MAN network as all the technologies
are combined together that creates the security problem.
o Needs Firewall & antivirus software: The data is transferred
on the internet which can be changed or hacked by the
hackers, so the firewall needs to be used. Some people can
inject the virus in our system so antivirus is needed to
protect from such a virus.
o High Setup cost: An installation cost of the WAN network
is high as it involves the purchasing of routers, switches.
o Troubleshooting problems: It covers a large area so fixing
the problem is difficult.

44. concon