INF1505 EXAM PACK 2023

INF1505ExamPack: INF1505May/June2014,INF1505Oct/Nov2013,INF1505May/June2013 INFORMATIONSYSTEMS:ANOVERVIEW 1.3TheBeginning:Transaction-ProcessingSystems Forthepast60years,transaction-processingsystems(TPSs)havebeenappliedtostructuredtaskssuchas recordkeeping,simpleclericaloperations,andinventorycontrol.Payroll,forexample,wasoneofthefirst applicationstobeautomated.TPSsfocusondatacollectionandprocessing,andtheyhaveprovidedenormous reductionsincosts. Computersaremostbeneficialintransaction-processingoperations.Theseoperationsarerepetitive,suchas printingnumerouschecks,orinvolveenormousvolumesofdata,suchasinventorycontrolinamultinational textilecompany.Whenthesesystemsareautomated,humaninvolvementisminimal.Forexample,inan automatedpayrollsystem,thereislittleneedformanagerialjudgmentinthetaskofprintingandsendingchecks, whichreducespersonnelcosts. QUESTION1.3.1 WhichoneofthefollowingisNOTanapplicationofTransactionProcessingSystems(TPS)? 1.Payrollsystem 2.Inventorycontrol 3.Recordkeeping 4.Gradingtests Answer: 4. Gradingtests 1.4ManagementInformationSystems Amanagementinformationsystem(MIS)isanorganizedintegrationofhardwareandsoftwaretechnologies,data, processes,andhumanelementsdesignedtoproducetimely,integrated,relevant,accurate,andusefulinformation fordecision-makingpurposes. Thehardwarecomponents,whicharediscussedinmoredetailinChapter2,includeinput,output,andmemory devicesandvarydependingontheapplicationandtheorganization.MISsoftware,alsocoveredinChapter2,can includecommercialprograms,softwaredevelopedin-house,orboth.Theapplicationororganizationdetermines thetypeofsoftwareused.ProcessesareusuallymethodsforperformingataskinanMISapplication.Thehuman elementincludesusers,programmers,systemsanalysts,andothertechnicalpersonnel.Thisbookemphasizes usersofMISs. IndesigninganMIS,thefirsttaskistoclearlydefinethesystem'sobjectives.Second,datamustbecollectedand analyzed.Finally,informationmustbeprovidedinausefulformatfordecision-makingpurposes. ManyMISapplicationsareusedinboththeprivateandpublicsectors.Forexample,anMISforinventorycontrol providesdata(suchashowmuchofeachproductisonhand),whatitemshavebeenordered,andwhatitemsare back-ordered.AnotherMISmightforecastsalesvolumeforthenextfiscalperiod.Thistypeofsystemusesrecent historicaldataandmathematicalorstatisticalmodelstogeneratethemostaccurateforecast,andsalesmanagers canusethisinformationforplanningpurposes.Inthepublicsector,anMISforapolicedepartment,forexample, couldprovideinformationsuchascrimestatistics,crimeforecasts,andallocationofpoliceunits.Managementcan examinethesestatisticstospotincreasesanddecreasesincrimeratesortypesofcrimesandanalyzethisdatato determinefuturedeploymentoflawenforcementpersonnel. Asyouwillseeinthisbook,manyorganizationsuseinformationsystemstogainacompetitiveadvantage.The informationboxonHertzdescribesoneexampleofthis.(Note:MISsareoftenreferredtoasjustinformation systems,andthesetermsareusedinterchangeablyinthisbook.) QUESTION1.4.1 The_____________componentofthemanagementinformationsystem(MIS)includesinput,output,and memorydevices. Downloaded by: LIBRARY | 1.Hardware 2.Software 3.Processing 4.Data Answer: 1. Hardware 1.5MajorComponentsofanInformationSystem Inadditiontohardware,software,andhumanelements,aninformationsystemincludesfourmajorcomponents, whicharediscussedinthefollowingsections:data,adatabase,aprocess,andinformation(seeExhibit1.3). QUESTION1.5.1 Atypicalinformationsystemincludeswhichofthefollowingcomponents? a.Dataentrysystem b.Database c.Process d.Information 1.A,B,C,D 2.B,C,D 3.C,D 4.A,B,C Answer: 2. B,C,D 1.5.aData: Thedatacomponentofaninformationsystemisconsideredtheinputtothesystem.Theinformationthatusers needaffectsthetypeofdatathatiscollectedandused. Generally,therearetwosourcesofdata:externalandinternal.Aninformationsystemshouldcollectdatafrom bothsources,althoughorganizationalobjectivesandthetypeofapplicationalsodeterminewhatsourcestouse. Internaldataincludessalesrecords,personnelrecords,andsoforth.Thefollowinglistshowssomeexamplesof externaldatasources:  Customers,competitors,andsuppliers  Governmentagenciesandfinancialinstitutions  Laborandpopulationstatistics  Economicconditions Typically,datahasatimeorientation,too.Forexample,pastdataiscollectedforperformancereports,andcurrent dataiscollectedforoperationalreports.Inaddition,futuredataispredictedforbudgetsorcashflowreports.Data canalsobecollectedindifferentforms,suchasaggregated(e.g.,subtotalsforcategoriesofinformation)or disaggregated(e.g.,itemizedlists).Anorganizationmightwantdisaggregateddatatoanalyzesalesbyproduct, territory,orsalesperson.Aggregateddatacanbeusefulforreportingoverallperformanceduringaparticularsales quarter,forexample,butitlimitstheabilityofdecisionmakerstofocusonspecificfactors. Downloaded by: LIBRARY | Distribution of this document is illegal S - The Marketplace to Buy and Sell your Study Material Ifanorganizationhasdefineditsstrategicgoals,objectives,andcriticalsuccessfactors,thenstructuringthedata componenttodefinewhattypeofdataiscollectedandinwhatformisusuallyeasy.Ontheotherhand,ifthereare conflictinggoalsandobjectivesorthecompanyisnotawareofcriticalsuccessfactors,manyproblemsindata collectioncanoccur,whichaffectsaninformationsystem'sreliabilityandeffectiveness. QUESTION1.5.a.1 Anorganizationmightwant_____________datatoanalysesalesbyproduct,territoryorsalesperson. 1.Disaggregated 2.Aggregated 3.Fragmented 4.Segregated Answer: 1. Disaggregated QUESTION1.5.a.2 Whichoneofthefollowingstatementsregardingthedatacomponentofaninformationsystemis INCORRECT? 1.Thedatacomponentofaninformationsystemisconsideredtheinputtothesystem 2.Datacanbecollectedindifferentforms,suchasaggregatedordisaggregated 3.Generally,therearethreesourcesofdata:internal,externalandgenerated 4.Typicallydatahasatimeorientation Answer: 3. Generally,therearethreesourcesofdata:internal,externalandgenerated QUESTION1.5.a.3 Thedatacomponentofaninformationsystemisconsideredthe______________tothesystem 1.Input 2.Output Answer: 1. Input 1.5.cProcess Thepurposeofaninformationsystem'sprocesscomponentisgeneratingthemostusefultypeofinformationfor makingdecisions.Thiscomponentgenerallyincludestransactionprocessingreportsandmodelsfordecision analysisthatcanbebuiltintothesystemoraccessedfromexternalsources. Aninformationsystemcanincludeawiderangeofmodelstosupportalllevelsofdecisionmaking.Usersshould beabletoqueryaninformationsystemandgenerateavarietyofreports.Inaddition,aninformationsystemshould beabletogrowwiththeorganizationsouserscanredefineandrestructuremodelsandincorporatenew informationintotheiranalyses. QUESTION1.5.c.1 Whichcomponentofaninformationsystemgenerallyincludestransactionprocessingreportsandmodels fordecisionanalysisthatcanbebuiltintothesystemoraccessedfromexternalsources? 1.Process 2.Information 3.Data 4.Knowledge Answer: 1. Process 1.5.dInformation Althoughtheymightseemthesame,dataandinformationaredifferent.Dataconsistsofrawfactsandbyitselfis S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material difficulttouseformakingdecisions.Information—theoutputofaninformationsystem—consistsoffactsthathave beenanalyzedbytheprocesscomponentand,therefore,aremoreusefultotheMISuser.Forexample,XYZ Company'stotalsaleslastmonthwere$5,000,000.Thisnumberisdata,becauseitdoesnottellyouhowthecompany performed.Diditmeetthesalesgoal?Didsalesincreaseordecreasefromthepreviousmonth?Howdidthecompany performagainstitstopcompetitors?Thesequestionsandmorecanbeansweredbytheinformationthatan informationsystemprovides. Thequalityofinformationisdeterminedbyitsusefulnesstousers,anditsusefulnessdeterminesthesuccessofan informationsystem.Informationisusefulifitenablesdecisionmakerstomaketherightdecisioninatimelymanner. Tobeuseful,informationmusthavethefollowingqualities:  Timeliness  Integrationwithotherdataandinformation  Consistencyandaccuracy  Relevance Ifinformationlacksanyofthesequalities,theresultsareincorrectdecisions,misallocationofresources,and overlookedwindowsofopportunity.Ifthesystemcannotgiveusersaminimumlevelofconfidenceinitsreliability,it willnotbeusedorusersmightdismissthereportsitgenerates.Informationmustprovideeitherabaseforusersto exploredifferentoptionsorinsightintotasks. Anotherfactoraffectingtheusefulnessofinformationistheinformationsystem'suserinterface.Becausethis interfacemustbeflexibleandeasytouse,mostinformationsystemsmakeuseofgraphicaluserinterfaces(GUIs), withfeaturessuchasmenusandbuttons.Tobeuseful,informationsystemsshouldalsoproduceinformationin differentformats,includinggraphics(e.g.,piechartsandbargraphs),tables,andexceptionreports,whichhighlight informationthatisoutsideaspecifiedrange.Supplyinginformationinavarietyofformatsincreasesthelikelihoodof usersunderstandingandbeingabletousetheinformation.Notethat,inadditiontotheformalinformationthatan informationsystemgenerates,usersneedtobeabletomakeuseofinformalinformation—suchasrumors, unconfirmedreports,andstories—whensolvingproblems. Theultimategoalofaninformationsystemistogeneratebusinessintelligence(BI),describedearlierinthischapter. Asyouwilllearnthroughoutthisbook,manydifferenttools,techniques,andtypesofinformationsystemtechnologies areusedtogenerateBI. QUESTION1.5.d.1 Thequalityofinformationisdeterminedbyits__________tousers 1.Usefulness 2.Accessibility 3.Availability 4.Integrity Answer: 1. Usefulness QUESTION1.5.d.2 Inaninformationsystem,informationmusthavewhichofthefollowingquality(qualities)? a.Accuracy b.Timeliness c.Formality d.Relevance 1.A,B,D 2.A,B,C,D 3.B,C,D 4.C Answer: 1. A,B,D 1.6.aTheImportanceofInformationSystems Informationisthesecondmostimportantresource(afterthehumanelement)inanyorganization.Timely,relevant, S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material andaccurateinformationisacriticaltoolforenhancingacompany'scompetitivepositioninthemarketplaceand managingthefourMsofresources:manpower,machinery,materials,andmoney. Tomanagetheseresources,differenttypesofinformationsystemshavebeendeveloped.Althoughallhavethe majorcomponentsshowninExhibit1.3,theyvaryinthekindofdatatheycollectandtheanalysestheyperform. Thissectiondiscussessomemajortypesofinformationsystems,focusingonthetypesofdataandanalysisused ineach. Apersonnelinformationsystem(PIS)orhumanresourceinformationsystem(HRIS)isdesignedtoprovide informationthathelpsdecisionmakersinpersonnelcarryouttheirtasksmoreeffectively.Webtechnologieshave playedamajorroleinimprovingtheefficiencyandeffectivenessofHRdepartments.Forexample,intranetsare oftenusedtoprovidebasicHRfunctions,suchasemployeescheckinghowmuchvacationtimetheyhaveleftor lookinguphowmuchtheyhaveintheir401(k)plans.Intranetsreducepersonnelcostsandspeedupresponsesto commonemployeerequests.AswewilldiscussinChapter7,anintranetisanetworkwithinanorganizationthat usesInternetprotocolsandtechnologiesforcollecting,storing,anddisseminatingusefulinformationthatsupports businessactivitiessuchassales,customerservice,humanresources,andmarketing.Themaindifferencebetween anintranetandtheInternetisthatintranetsareprivateandtheInternetispublic.APIS/HRISsupportsthefollowing actions,amongothers: Choosingthebestjobcandidate Schedulingandassigningemployees Predictingtheorganization'sfuturepersonnelneeds Providingreportsandstatisticsonemployeedemographics Allocatinghumanandfinancialresources InformationTechnologiesatUPS Establishedin1907,UnitedParcelService(UPS)isnowaglobalcompanyworth$49.7billion.Itusesa sophisticatedinformationsystemtomanagethedeliveryofmorethan14millionpackagesaday.Thecompany usesseveraltypesofnetworksinitsoperations—particularly,GPSandwirelessnetworks.ItsGPSnetworkincludes analgorithmthathashelpeddriversreducethenumberofleftturnstheyhavetotake,particularlyoncommercial roads.This,alongwithavehicletelemetricsystem,hasreducedthenumberofaccidentsanddeliverytimes,thus savingthecompanyover20millionmilesayear. Tobetterservecustomers,UPShasdevelopedUPSDeliveryIntercept,aWeb-basedservicethatallowscustomers tointerceptandreroutepackagesbeforetheyaredelivered,thusavoidingpotentiallycostlymistakesandwasted timeandcosts.UPScallsthetechnologybehindthisservicePackageFlowTechnology,whichisalsousedtomap efficientroutesfordriversandmarkpackagesforspecialhandling.KurtKuehn,seniorvicepresidentofworldwide salesandmarketing,says,“InnovationslikePackageFlowTechnologyandserviceslikeUPSDeliveryInterceptare keycomponentsofUPS'sdrivetotreateachofourmillionsofcustomersasifthey'reouronlycustomer.We're constantlyworkingonnewandinnovativewaystoharnesstechnologytohelpourcustomersmeettheirunique needs.”Footnote Alogisticsinformationsystem(LIS)isdesignedtoreducethecostoftransportingmaterialswhilemaintainingsafe andreliabledelivery.ThefollowingareafewexamplesofdecisionssupportedbyanLIS: Improvingroutinganddeliveryschedules Selectingthebestmodesoftransportation Improvingtransportationbudgeting Improvingshipmentplanning TheinformationboxfeaturingUPSshowsusesofinformationsystemsandinformationtechnologies,particularly logisticsinformationsystems. Amanufacturinginformationsystem(MFIS)isusedtomanagemanufacturingresourcessocompaniescanreduce manufacturingcosts,increaseproductquality,andmakebetterinventorydecisions.MFISscanperformmanytypes ofanalysiswithahighdegreeoftimelinessandaccuracy.Forexample,managerscoulduseanMFIStoassessthe effectonfinalproductcostsofa7percentincreaseinrawmaterialsordeterminehowmanyassembly-lineworkers areneededtoproduce200automobilesinthenext3weeks.HerearesomedecisionsthatanMFISsupports:  Orderingdecisions  Productcostcalculations  Spaceutilization  Thebidevaluationprocessusedwithvendorsandsuppliers  Analysisofpricechangesanddiscounts Thegoalofafinancialinformationsystem(FIS)istoprovideinformationtofinancialexecutivesinatimelymanner. AnFISisusedtosupportthefollowingdecisions,amongothers: S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material  Improvingbudgetallocation  Minimizingcapitalinvestmentrisks  Monitoringcosttrends  Managingcashflows  Determiningportfoliostructures Inaddition,marketinginformationsystems(MKISs)areusedtoimprovemarketingdecisions.AneffectiveMKIS shouldprovidetimely,accurate,andintegratedinformationaboutthemarketingmix(price,promotion,place,and product).HerearesomedecisionsthatanMKISsupports: Analyzingmarketshare,sales,andsalespersonnel Salesforecasting Priceandcostanalysisofitemssold QUESTION1.6.a.1 Fromthelistbelow,howmanyareNOTdecisionsthatamanufacturinginformationsystem(MFIS) supports? a.Orderingdecisions b.Productcostcalculations c.Spaceutilization d.Selectingthebestmodeoftransport e.Determiningportfoliostructures f. Salesforecasting 1.2 2.3 3.5 4.6 Answer: 2. 3 1.6.cPorter'sFiveForcesModel:UnderstandingtheBusinessEnvironment HarvardBusinessSchool'sMichaelPortercreatedacomprehensiveframeworkcalledtheFiveForcesModelfor analyzinganorganization,itspositioninthemarketplace,andhowinformationsystemscouldbeusedtomakethe organizationmorecompetitive.Thefiveforces,showninExhibit1.4,are:  Buyerpower  Supplierpower  Threatofsubstituteproductsorservices  Threatofnewentrants  Rivalryamongexistingcompetitors Buyerpowerishighwhencustomershavemanychoicesandlowwhentheyhavefewchoices.Typically, organizationstrytolimitbuyers’choicesbyofferingservicesthatmakeitdifficultforcustomerstoswitch,whichis S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material essentiallyusingadifferentiationstrategy.Forexample,DellComputerwasamongthefirsttooffercomputer customizationoptionstocustomers,andothercomputermanufacturersfollowedsuit.Grocerystores,suchas Sam'sClub,offerclubcardsthatencouragecustomerstoshopbygivingthembigdiscounts,anexampleofoverall costleadershipstrategies.Similarly,airlinesandhotelsofferfreemileageandpointswhencustomersusetheir services.Informationsystemscanmakemanagingthesestrategieseasierandmorecosteffective. Organizationsusethesestrategiestoincreasecustomerloyalty,thuscombattingthethreatofnewentrantsor substituteproducts.However,certaininformationtechnologytools,suchastheInternet,haveevenedtheplaying fieldbygivingcustomersmoreaccesstoallsortsofdata,suchasthevariouspricesforproductsandservices. Thisincreasesbuyers’bargainingpoweranddecreasessupplierpower,whichisdiscussednext. Supplierpowerishighwhencustomershavefeweroptionsandlowwhencustomershavemoreoptions. Organizationsmightuseinformationsystemstomaketheirproductsandservicescheaperortooffermore servicesinordertodistinguishthemselvesfromcompetitors(anotheruseofadifferentiationstrategy).Netflix,for example,usesinformationtechnologiestoofferproductsandservices,whichincreasesitspowerinthe marketplace.(Forexamplesofhowthesefocusstrategiesgetused,seetheinformationboxonNetflix.) Organizationshavetoolsotherthaninformationsystemsandtechnologiestoincreasetheirpower.Forexample, drugcompaniesgetpatentsfortheirproductstoreducecompetition. Thethreatofcustomerschoosingsubstituteproductsorservicesishighwhenmanyalternativestoan organization'sproductsandservicesareavailable.Someorganizationsaddservices—suchasA's personalizedrecommendations—tomaketheirpositionsinthemarketplacemoredistinctive.Otherorganizations usefeestodiscouragecustomersfromswitchingtoacompetitor,suchaswhencellphonecompaniesadd chargesforswitchingtoanotherproviderbeforethecustomercontractisup. Thethreatofnewentrantsintothemarketplaceislowwhenduplicatingacompany'sproductorserviceisdifficult. Organizationsoftenusefocusstrategiestoensurethatthisthreatremainslow.Forexample,developingasearch enginethatcouldcompetesuccessfullywithGooglewouldbedifficult.Inaddition,organizationsuseinformation technologiestoincreasecustomerloyalty,asmentionedpreviously,whichreducesthethreatofnewentrants.For example,banksofferfreebillpayingtoattractcustomersandkeepthemfromswitchingtoanotherbank;settingup abill-payingserviceatanotherbanktakestimethatmostcustomersdonotwanttospend.Similarly,after customizingtheirhomepageswithoptionsofferedbysitessuchasYahoo!andGoogle,manyusersdonotwantto repeatthisprocessatanewsite. Rivalryamongexistingcompetitorsishighwhenmanycompetitorsoccupythesamemarketplaceposition;itislow whentherearefewcompetitors.Forexample,onlinebrokeragefirmsoperateinahighlycompetitiveenvironment, sotheyuseinformationtechnologiestomaketheirservicesunique. QUESTION1.6.c.1 WhichofthefollowingareincludedinPorter’sfiveforces? a.Buyerpower b.Technologicalskill c.Supplierpower d.Threatofsubstituteproductsorservices 1.A,B,C,D 2.B,C,D 3.A,C,D 4.A,D Answer: 3. A,C,D QUESTION1.6.c.2 ThefollowingdiagramillustratesPortersFiveForcesModel.WhatforcedoesArepresent? S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material 1.Rivalryamongexistingcompetitors 2.Overallcostofleadership 3.Differentiation 4.Focus Answer: 1. Rivalryamongexistingcompetitors S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material 1.6.bUsingInformationTechnologiesforaCompetitiveAdvantage MichaelPorter,aprofessoratHarvardBusinessSchool,identifiedthreestrategiesforsuccessfullycompetingin themarketplace:  Overallcostleadership  Differentiation  Focus Informationsystemscanhelporganizationsreducethecostofproductsandservicesand,ifdesignedcorrectly, theycanassistwithdifferentiationandfocusstrategies,too.Throughoutthisbook,youwillseemanyexamplesof thecostsavingsthatorganizationshaveachievedwithinformationsystemsandtechnologies.Forexample, Walmarthasbeenusingoverallcostleadershipstrategiessuccessfully(seetheinformationbox). Informationtechnologiescanhelpbottom-lineandtop-linestrategies.Thefocusofabottom-linestrategyis improvingefficiencybyreducingoverallcosts.Atop-linestrategyfocusesongeneratingnewrevenuebyoffering newproductsandservicestocustomersorincreasingrevenuebysellingexistingproductsandservicestonew customers.Forexample,e-commercebusinessesareadaptingbusinessmodelstoreducedistributioncosts dramatically.AgoodexampleisantivirusvendorsusingtheInternettodistributesoftware.Forasubscriptionfeeof around$30,youcandownloadthesoftwareandreceiveupdatesforayear.WithouttheInternetforeasy, inexpensivedistribution,vendorscouldnotaffordtooffersoftwareatsuchalowprice. Informationtechnologiescanhelpbottom-lineandtop-linestrategies. AswewilldiscussinChapter11,manyorganizationsuseenterprisesystems,suchassupplychainmanagement (SCM),customerrelationshipmanagement(CRM),enterpriseresourceplanning(ERP),andcollaborationsoftware, toreducecostsandimprovecustomerservice.Thegoalofthesesystemsistouseinformationtechnologiesto createthemostefficient,effectivelinkbetweensuppliersandconsumers.AsuccessfulCRMprogram,forexample, helpsimprovecustomerserviceandcreatealong-termrelationshipbetweenanorganizationanditscustomers. Fordifferentiationstrategies,organizationstrytomaketheirproductsandservicesdifferentfromtheircompetitors. ApplehasbeensuccessfulwiththisstrategybydesigningitscomputerstolookmuchdifferentfromPCsand focusingonitscomputers’easeofuse.Asanotherexample,AsdifferentiateditsWebsitebyusing certaininformationtechnologies,suchaspersonalizationtechnologies(coveredinmoredetailinChapter11)to recommendproductstocustomersbasedontheirpreviouspurchases.Asousestheone-click systemforfastcheckout.Withthissystem,customerscanentercreditcardnumbersandaddressesonceand,in subsequentvisits,simplyclickoncetomakeapurchase,withouthavingtoenterinformationagain. Withfocusstrategies,organizationsconcentrateonaspecificmarketsegmenttoachieveacostordifferentiation advantage.ApplehasalsousedthisstrategytotargetiPhonestoconsumerusersratherthanbusinessusers. Similarly,Macintoshcomputersareheavilymarketedtocreativeprofessionalssuchasdesigners,photographers, andwriters.Asanotherexample,Abercrombie&Fitchtargetshigh-endclothingtolow-incomecustomers,suchas teenagersandyoungadults,whileNordstromtargetstheirhigh-endclothingtohigh-incomecustomers.Information technologiescouldassistthesecompaniesinreachingtheirtargetmarketsegmentsmorecosteffectively. Rememberthatfocusanddifferentiationstrategiesworkonlyuptoacertainpoint.Customersareoftenwillingto paymoreforauniqueproductorserviceoronewithaspecificfocus.However,coststillplaysamajorrole.Ifa productorservicebecomestooexpensive,customersmightnotbewillingtopurchaseit. QUESTION1.6.b.1 Thefocusofa______________strategyforsuccessfullycompletinginamarketplaceisimprovingefficiencyby reducingoverallcosts 1. Top-line 2. Bottom-line Answer: 2. Bottom-line COMPUTERS:THEMACHINESBEHINDCOMPUTING S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material 2.1DefiningaComputer Ifairplaneshaddevelopedascomputershavedeveloped,todayyouwouldbeabletogoaroundtheglobeinless than20minutesforjust50cents.Computershavegonethroughdrasticchangesinashorttime.Forexample,a computerthatweighedmorethan18tons60yearsagohasbeenreplacedbyonethatnowweighslessthantwo pounds.Today'scomputeris100timesmorepowerfulandcostslessthan1percentofthe60-year-oldcomputer. Ifairplaneshaddevelopedascomputershavedeveloped,todayyouwouldbeabletogoaroundtheglobeinless than20minutesforjust50cents. AsyoulearnedinChapter1,youusecomputerseverydayforamultitudeofpurposes.Youevenusethemindirectly whenyouuseapplianceswithembeddedcomputers,suchasTVsandmicrowaves.Computershavebecomeso ubiquitous,infact,thatacashlessandchecklesssocietyislikelyjustaroundthecorner.Similarly,computersmight eliminatetheneedforbusinesstravel.Evennow,executivesseldomneedtoleavetheirofficesformeetingsin otherlocationsbecauseoftechnologiessuchascomputerconferencingandtelepresencesystems. Computersareusedinawidevarietyoftasks,includingreportdistributioninbusinesses,rocketguidancecontrolin theNASAspaceprogram,andDNAanalysisinmedicalresearch.Thisbookcouldnothavebeenpublishedwithout theuseofcomputers.Thetextwastypedandrevisedwithword-processingsoftware,andcompositionsoftware wasusedtotype-setthepages.Printing,warehousing,inventorycontrol,andshippingwereaccomplishedwiththe helpofcomputers. Sowhatisacomputer?Manydefinitionsarepossible,butinthisbookacomputerisdefinedasamachinethat acceptsdataasinput,processesdatawithouthumaninterventionbyusingstoredinstructions,andoutputs information.Theinstructions,alsocalledaprogram,arestep-by-stepdirectionsforperformingaspecifictask, writteninalanguagethecomputercanunderstand.Rememberthatacomputeronlyprocessesdata(rawfacts);it cannotchangeorcorrectthedatathatisentered.Ifdataiserroneous,theinformationthecomputerprovidesis alsoerroneous.ThisruleissometimescalledGIGO:garbagein,garbageout. Towriteacomputerprogram,firstyoumustknowwhatneedstobedone,andthenyoumustplanamethodto achievethisgoal,includingselectingtherightlanguageforthetask.Manycomputerlanguagesareavailable;the languageyouselectdependsontheproblembeingsolvedandthetypeofcomputeryouareusing.Regardlessof thelanguage,aprogramisalsoreferredtoasthesourcecode.Thissourcecodemustbetranslatedintoobject code—consistingofbinary0sand1s.Binarycode—asetofinstructionsusedtocontrolthecomputer—uses0sand 1s,whichthecomputerunderstandsasonoroffsignals.Youwilllearnmoreaboutthebinarysystemand computerlanguageslaterinthischapter. QUESTION2.1.1 Acomputeronlyprocesses________________ 1.Rawfacts(data) 2.Information 3.Knowledge 4.Programs Answer: 1. Rawfacts(data) QUESTION2.1.2 A(n)_____________codemustbetranslatedinto______________codeinorderforthecomputertobeableto readandexecute 1.Source,object 2.Object,source Answer: 1. Source,object S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material 2.1aComponentsofaComputerSystem Acomputersystemconsistsofhardwareandsoftware.Hardwarecomponentsarephysicaldevices,suchas keyboards,monitors,andprocessingunits.Thesoftwarecomponentconsistsofprogramswrittenincomputer languages. Exhibit2.1showsthebuildingblocksofacomputer.Inputdevices,suchaskeyboards,areusedtosenddataand informationtothecomputer.Outputdevices,suchasmonitorsandprinters,displaytheoutputacomputer generates. Main(primary)memoryiswherecomputersstoredataandinstructions,similartoahumanbrain.Thecentral processingunit(CPU)istheheartofacomputer.Itisdividedintotwocomponents:thearithmeticlogicunit (ALU)andthecontrolunit.TheALUperformsarithmeticoperations(+,−,*,/)aswellascomparisonorrelational operations(<,>,=);thelatterareusedtocomparenumbers.Thecontrolunittellsthecomputerwhattodo,such asinstructingthecomputerwhichdevicetoreadorsendoutputto. Somecomputershaveasingleprocessor;othercomputers,calledmultiprocessors,containmultipleprocessors. MultiprocessingistheuseoftwoormoreCPUsinasinglecomputersystem.Generally,amultiprocessor computerperformsbetterthanasingle-processorcomputerinthesamewaythatateamwouldperformbetter thananindividualonalarge,time-consumingproject.Somecomputersuseadual-coreprocessor,whichis essentiallytwoprocessorsinone,toimproveprocessingpower.Dual-coreprocessorsarecommoninnewPCs andApplecomputers. Anothercomponentthataffectscomputerperformanceisabus,whichisthelinkbetweendevicesconnected tothecomputer.Abuscanbeparallelorserial,internal(local)orexternal.Aninternalbusenables communicationbetweeninternalcomponents,suchasavideocardandmemory;anexternalbusiscapableof communicatingwithexternalcomponents,suchasaUSBdevice. Otherfactorsthataffectcomputerperformanceincludetheprocessorsizeandtheoperatingsystem(OS).In recentyears,32-bitand64-bitprocessorsandOSshavecreatedalotofinterest.A32-bitprocessorcanuse232 bytes(4GB)ofRAM;and,intheory,a64-bitprocessorcanuse264bytes(16EB,orexabytes)ofRAM.Soa computerwitha64-bitprocessorcanperformcalculationswithlargernumbersandbemoreefficientwith smallernumbers;italsohasbetteroverallperformancethana32-bitsystem.However,totakeadvantageofthis higherperformance,youmustalsohavea64-bitOS. Exhibit2.2showsadditionalcomponentsofacomputersystem.Adiskdriveisaperipheraldeviceforrecording, storing,andretrievinginformation.ACPUcase(alsoknownasacomputerchassisortower)istheenclosure containingthecomputer'smaincomponents.Amotherboardisthemaincircuitboardcontainingconnectorsfor attachingadditionalboards.Inaddition,itusuallycontainstheCPU,BasicInput/OutputSystem(BIOS),memory, storage,interfaces,serialandparallelports,expansionslots,andallthecontrollersforstandardperipheral devices,suchasthedisplaymonitor,diskdrive,andkeyboard.Aserialportisacommunicationinterface throughwhichinformationistransferredonebitatatime;aparallelportisaninterfacebetweenacomputer andaprinterthatenablesthecomputertotransfermultiplebitsofinformationtotheprintersimultaneously. S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material QUESTION2.1.a.1 A_________portisacommunicationinterfacethroughwhichinformationistransferredonebitatatime,a ___________portisaninterfacebetweenacomputerandprinterthatenablesthecomputertotransfer multiplebitsofinformationtotheprintersimultaneously 1.Parallel,serial 2.Serial,parallel 3.Synchronous,asynchronous 4.Asynchronous,synchronous Answer: 2. Serial,parallel QUESTION2.1.a.2 A(n)______isalinkbetweendevicesconnectedtothecomputer 1.Arithmeticlogicunit(ALU) 2.Controlunit 3.Logicunit 4.Bus Answer: 4. Bus 2.2TheHistoryofComputerHardwareandSoftware Majordevelopmentsinhardwarehavetakenplaceoverthepast60years.Tomakethesedevelopmentsmore clear,computersareoftencategorizedinto“generations”thatmarktechnologicalbreakthroughs.Beginningin the1940s,first-generationcomputersusedvacuumtubetechnology.Theywerebulkyandunreliable,generated excessiveheat,andweredifficulttoprogram.Second-generationcomputersusedtransistorsandwerefaster, morereliable,andeasiertoprogramandmaintain.Third-generationcomputersoperatedonintegratedcircuits, whichenabledcomputerstobeevensmaller,faster,morereliable,andmoresophisticated.Remotedataentry andtelecommunicationswereintroducedduringthisgeneration.Fourth-generationcomputerscontinuedseveral trendsthatfurtherimprovedspeedandeaseofuse:miniaturization,very-large-scaleintegration(VLSI)circuits, widespreaduseofpersonalcomputers,andopticaldiscs(discswrittenorencodedandreadusingalaseroptical device).Thecurrentfifth-generationcomputersincludeparallel-processing(computerscontaininghundredsor thousandsofCPUsforrapiddataprocessing),galliumarsenidechipsthatrunathigherspeedsandconsume lesspowerthansiliconchips,andopticaltechnologies.Table2.1summarizesthesehardwaregenerations. Table2.1 Hardwaregenerations Generation Date Majortechnologies Example First 1946–1956 Vacuumtube ENIAC Second 1957–1963 Transistors IBM7094, 1401 S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material Third 1964–1970 Integratedcircuits,remotedataentry, telecommunications IBM360,370 Fourth 1971–1992 Miniaturization,VLSI,personalcomputers,opticaldiscs CrayXMP,Cray II Fifth 1993–presen t Parallelprocessing,galliumarsenidechips,optical technologies IBMSystem z10 Becausesiliconcannotemitlightandhasspeedlimitations,computerdesignershaveconcentratedon technologyusinggalliumarsenide,inwhichelectronsmovealmostfivetimesfasterthaninsilicon.Devices madewiththissyntheticcompoundcanemitlight,withstandhighertemperatures,andsurvivemuchhigher dosesofradiationthansilicondevices.Themajorproblemswithgalliumarsenidearedifficultiesinmass production.Thismaterialissofterandmorefragilethansilicon,soitbreaksmoreeasilyduringslicingand polishing.Becauseofthehighcostsanddifficultyofproduction,themilitaryiscurrentlythemajoruserofthis technology.However,researchcontinuestoeliminatesomeshortcomingsofthistechnology. Thefieldofopticaltechnologiesinvolvestheapplicationsandpropertiesoflight,includingitsinteractionswith lasers,fiberoptics,telescopes,andsoforth.Thesetechnologiesofferfasterprocessingspeed,parallelism (severalthousandlightbeamscanpassthroughanordinarydevice),andinterconnection;muchdenserarraysof interconnectionsarepossiblebecauselightraysdonotaffecteachother.Opticalcomputingisinitsinfancy,and moreresearchisneededtoproduceafull-featuredopticalcomputer.Nevertheless,storagedevicesusingthis technologyarerevolutionizingthecomputerfieldbyenablingmassiveamountsofdatatobestoredinverysmall spaces. Computerlanguagesandsoftwarehavealsodevelopedthroughfivegenerations.Theyarediscussedinmore detailinthe“ComputerLanguages”section,butTable2.2summarizesthesegenerations. Generation Majorattribute First Machinelanguage Second Assemblylanguage Third High-levellanguage Fourth Fourth-generationlanguage Fifth Naturallanguageprocessing(NLP) Theinformationboxtitled“IBMWatsonWinsJeopardy”describesasupercomputerthathasseveralfeaturesof afifth-generationcomputeraswellasartificialintelligencecapabilities. QUESTION2.2.1 Whichstatement(s)regardingthehistoryofcomputerhardwareis(are)CORRECT? a. First-generationcomputersusedvacuumtubetechnology b. Second-generationcomputersoperatedonintegratedcircuitswhichenabledcomputerstobeevensmaller, faster,morereliableandmoresophisticated c. Third-generationcomputersusedtransistorsandwerefaster,morereliableandeasiertoprogramand maintain d. Thecurrentfourthgenerationcomputersincludedparallel-processing,galliumarsenidechipsthatrunat higherspeedsandconsumedlesspowerthansiliconchipsandopticaltechnologies 1. AandD 2. B,C,D 3. A 4. D Answer: b. Second-generationcomputersoperatedonintegratedcircuitswhichenabledcomputerstobe evensmaller,faster,morereliableandmoresophisticated c. Third-generationcomputersusedtransistorsandwerefaster,morereliableandeasierto programandmaintain 1. AandD QUESTION2.2.2 S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material Transistorwasthemajortechnologyusedduringthe_______generationofhardware 1.First 2.Second 3.Third 4.Fourth Answer: 2. Second QUESTION2.2.3 Thefollowingdiagramdepictscomputerlanguagetrends.Identifythemajorattributesfor“A”,“B”,“C”: 1.Machinelanguage,high-levellanguage,naturallanguageprocessing(NLP) 2.High-levellanguage,NLP,machinelanguage 3.NLR,objectorientedlanguage,machinelanguage 4.Object-orientatedlanguage,machinelanguage,NLP Answer: 1. Machinelanguage,high-levellanguage,naturallanguageprocessing(NLP) QUESTION2.2.4 Miniaturizationoccurredinwhichgenerationofcomputerhardware? 1.Firstgeneration 2.Fifthgeneration 3.Fourthgeneration 4.Thirdgeneration Answer: 3. Fourthgeneration 2.3.aSpeed Computersprocessdatawithamazingspeed.Theyarecapableofrespondingtorequestsfasterthan humanscan,whichimprovesefficiency.Today'shigh-speedcomputersmakeitpossiblefor knowledgeworkerstoperformtasksmuchfasterthanwiththeslowercomputersofthepast. Typically,computerspeedismeasuredasthenumberofinstructionsperformedduringthefollowing fractionsofasecond: Millisecond:1/1,000ofasecond Microsecond:1/1,000,000ofasecond Nanosecond:1/1,000,000,000ofasecond Picosecond:1/1,000,000,000,000ofasecond QUESTION2.3.a.1 Typicallycomputerspeedismeasuredasthenumberofinstructionsperformedduringfractionsofa secondranginginorderfrom____________ 1.Microsecond,nanosecond,picoseconds,millisecond 2.Nanosecond,picoseconds,millisecond,microsecond 3.Millisecond,microsecond,nanosecond,picosecond 4.Picosecond,millisecond,microsecond,nanosecond Answer: 3. Millisecond,microsecond,nanosecond,picosecond S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material 2.3.cStorageandRetrieval Storagemeanssavingdataincomputermemory,andretrievalmeansaccessingdatafrommemory.Computers canstorevastquantitiesofdataandlocateaspecificitemquickly,whichmakesknowledgeworkersmore efficientinperformingtheirjobs. Incomputers,dataisstoredinbits.Abitisasinglevalueof0or1,and8bitsequal1byte.Abyteisthesizeofa character.Forexample,thewordcomputerconsistsof8charactersor8bytes(64bits).Table2.3showsstorage measurements. Table2.3Storagemeasurements(approximations) 1bit Asinglevalueof0or1 8bits 1byteorcharacter 2 10 bytes 1000bytes,or1kilobyte(KB) 2 20 bytes 1,000,000bytes,or1megabyte(MB) 2 30 bytes 1,000,000,000bytes,or1gigabyte(GB) 2 40 bytes 1,000,000,000,000bytes,or1terabyte(TB) 2 50 bytes 1,000,000,000,000,000bytes,or1petabyte(PB) 2 60 bytes 1,000,000,000,000,000,000bytes,or1exabyte(EB) Computersandcommunicationsystemsusedatacodestorepresentandtransferdatabetweencomputersand networksystems.Themostcommondatacodefortextfiles,PCapplications,andtheInternetisAmerican StandardCodeforInformationInterchange(ASCII),developedbytheAmericanNationalStandardsInstitute.In anASCIIfile,eachalphabetic,numeric,orspecialcharacterisrepresentedwitha7-bitbinarynumber(astring of0sor1s).Upto128(27)characterscanbedefined.Therearetwoadditionaldatacodesusedbymany operatingsystems:UnicodeandExtendedASCII.Unicodeiscapableofrepresenting256(28)characters,and ExtendedASCIIisan8-bitcodethatalsoallowsrepresentationof256characters. BeforetheASCIIformat,IBM'sExtendedBinaryCodedDecimalInterchangeCode(EBCDIC)waspopular.Inan EBCDICfile,eachalphabetic,numeric,orspecialcharacterisrepresentedwithan8-bitbinarynumber. QUESTION2.3.c.1 Ina(n)________file,eachalphabetic,numeric,orspecialcharacterisrepresentedwitha7-bitbinary number 1.Extendedbinarycodeddecimalinterchangecode(EBCDIC) 2.Unicode 3.Americanstandardcodeforinformationinterchange(ASCII) 4.ExtendedASCII Answer: 3. Americanstandardcodeforinformationinterchange(ASCII) QUESTION2.3.c.2 Computersandcommunicationssystemsuse_________torepresentandtransferinformationbetween computersandnetworksystems 1.Lightpens 2.Datacodes 3.Opticalmarkrecognition(OMR) 4.Opticalcharactercodes(OCR) Answer: 2. Datacodes S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material 2.5Input,Output,andMemoryDevices 2.5.aInputDevices Inputdevicessenddataandinformationtothecomputer.Theyareconstantlybeingimprovedtomakedatainput easier.Examplesofinputdevicesinclude: Keyboard—Thisisthemostwidelyusedinputdevice.Originally,keyboardsweredesignedtoresemble typewriters,butseveralmodificationshavebeenmadetoimprovetheireaseofuse.Forexample,most keyboardsincludecontrolkeys,arrowkeys,functionkeys,andotherspecialkeys.Inaddition,somekeyboards, suchasthesplitkeyboard,havebeendevelopedforbetterergonomics.Youcanperformmostcomputerinput taskswithkeyboards,butforsometasksascannerormouseisfasterandmoreaccurate. Mouse—Thispointingdevicemovesthecursoronthescreen,allowingfast,precisecursorpositioning.With programsthatusegraphicalinterfaces,suchasMicrosoftWindowsorMacOS,themousehasbecometheinput deviceofchoice. Touchscreen—Thisisacombinationofinputdevices,usuallyworkingwithmenus.Sometouchscreensrelyon lightdetectiontodeterminewhichmenuitemhasbeenselected;othersarepressuresensitive.Touchscreens areofteneasiertousethankeyboards,buttheymightnotbeasaccuratebecauseselectionscanbemisreador mistouched.Youprobablysawtouchscreensusedextensivelyontelevisionduringthe2012presidentialelection toquicklyshowelectoralmapsandanalyzeelectiondataindifferentways. Lightpen—Thisisalight-sensitivestylusconnectedtothemonitorwithacable.Whenitisplacedonanonscreenlocation,thedatainthatspotissenttothecomputer.Thedatacanbecharacters,lines,orblocks.Alight peniseasytouse,inexpensive,andaccurate,anditisparticularlyusefulforengineersandgraphicdesigners whoneedtomakemodificationstotechnicaldrawings. Trackball—Thisiskeptinastationarylocation,butitcanberolledonitsaxistocontroltheon-screencursor. Trackballsoccupylessspacethanamouse,sotheyareidealfornotebookcomputers.However,positioningwith atrackballissometimeslessprecisethanwithamouse. Datatablet—Thisconsistsofasmallpadandapen.Menusaredisplayedonthetablet,andyoumakeselections withthepen.Datatabletsareusedmostwidelyincomputer-aideddesignandmanufacturingapplications. Barcodereader—Thisisanopticalscannerthatuseslaserstoreadcodesinbarform.Thesedevicesarefast andaccurateandhavemanyapplicationsininventory,dataentry,andtrackingsystems.Theyareusedmostly withUPCsystemsinretailstores. Opticalcharacterreader(OCR)—Thisworksonthesameprincipleasabarcodereaderbutreadstextinstead. OCRsmustbeabletorecognizemanyspecialcharactersanddistinguishbetweenuppercaseandlowercase letters,sousingoneismoredifficultthanusingabarcodereader.Nevertheless,OCRshavebeenused successfullyinmanyapplicationsandareimprovingsteadily.TheUnitedStatesPostalServiceusesOCRstosort mail. Magneticinkcharacterrecognition(MICR)system—Thisreadscharactersprintedwithmagneticinkandisused primarilybybanksforreadingtheinformationatthebottomofchecks. Opticalmarkrecognition(OMR)system—Thisissometimescalleda“marksensing”systembecauseitreads marksonpaper.OMRsareoftenusedtogrademultiple-choiceandtrue/falsetests. QUESTION2.5.a.1 WhichoneofthefollowingstatementsregardingtheuseofinputdevicesisINCORRECT? 1.Alightpenisusedforengineersandgraphicdesignerswhoneedtomakemodificationsto technicaldrawings 2.Datatabletsareusedmostwidelyincomputer-aideddesignandmanufacturingapplications 3.Opticalcharacterreaders(OCRs)areusedmostlywithuniversalproductcode(UPC)systemsin retailstores 4.Opticalmarkrecognitions(OMRs)areoftenusedtogrademultiple-choiceandtrue/falsequestions Answer: 4. Opticalmarkrecognitions(OMRs)areoftenusedtogrademultiple-choiceand true/falsequestions S - The Marketplace to Buy and Sell your Study Material Downloaded by: LIBRARY | Distribution of this document is illegal Want to earn $103 per month? S - The Marketplace to Buy and Sell your Study Material 2.5.cMemoryDevices Twotypesofmemoryarecommontoanycomputer:mainmemoryandsecondarymemory.Mainmemorystores dataandinformationandisusuallyvolatile,meaningitscontentsarelostwhenelectricalpoweristurnedoff. Secondarymemory,whichisnonvolatile,holdsdatawhenthecomputerisofforduringthecourseofaprogram's operation.Italsoservesasarchivalstorage.Mainmemoryplaysamajorroleinacomputer'sperformance;tosome extent,themorememoryacomputerhas,thefasterandmoreefficientitsinput/output(I/O)operationsare. Graphicscards,alsocalledvideoadapters,enhancecomputerperformance,too.High-endgraphicscardsare importantforgraphicdesigners,whoneedfastrenderingof3Dimages.Manyvideogamesalsorequirehigh-end graphicscardsforthebestdisplay. MainMemoryDevices Themostcommontypeofmainmemoryisasemiconductormemorychipmadeofsilicon.Asemiconductor memorydevicecanbevolatileornonvolatile.Volatilememoryiscalledrandomaccessmemory(RAM),although youcouldthinkofitas“read-writememory.”Inotherwords,datacanbereadfromandwrittentoRAM.Some examplesofthetypeofinformationstoredinRAMincludeopenfiles,theClipboard'scontents,runningprograms, andsoforth. AspecialtypeofRAM,calledcacheRAM,residesontheprocessor.BecausememoryaccessfrommainRAM storagegenerallytakesseveralclockcycles(afewnanoseconds),cacheRAMstoresrecentlyaccessedmemoryso theprocessorisn'twaitingforthememorytransfer. Nonvolatilememoryiscalledread-onlymemory(ROM);datacannotbewrittentoROM.Thetypeofdatausually storedinROMincludesBIOSinformationandthecomputersystem'sclock.TherearetwoothertypesofROM. Programmableread-onlymemory(PROM)isatypeofROMchipthatcanbeprogrammedwithaspecialdevice. However,afterithasbeenprogrammed,thecontentscannotbeerased.Erasableprogrammableread-only memory(EPROM)issimilartoPROM,butitscontentscanbeerasedandreprogrammed. SecondaryMemoryDevices Secondarymemorydevicesarenonvolatileandusedforstoringlargevolumesofdataforlongperiods.As mentionedearlier,theycanalsoholddatawhenthecomputerisofforduringthecourseofaprogram'soperation. Therearethreemaintypes:magneticdisks,magnetictape,andopticaldiscs.Largeenterprisesalsousestorage areanetworksandnetwork-attachedstorage(discussedinthenextsection)forstoringmassiveamountsofdatain anetworkenvironment. Amagneticdisk,madeofMylarormetal,isusedforrandom-accessprocessing.Inotherwords,datacanbe accessedinanyorder,regardlessofitsorderonthesurface.Magneticdisksaremuchfasterbutmoreexpensive thantapedevices. Magnetictape,madeofaplasticmaterial,resemblesacassettetapeandstoresdatasequentially.Recordscanbe storedinablockorseparately,withagapbetweeneachrecordorblock,calledtheinterrecordgap(IRG).Magnetic tapeissometimesusedforstoringbackups,althoughothermediaaremorecommonnow.Exhibit2.3showsboth typesofmagneticmemorydevices. Exhibit2.3 Opticaldiscsuselaserbeamstoaccessandstoredata.Opticaltechnologycanstorevastamountsofdataandis durable.ThreecommontypesofopticalstorageareCD-ROMs,WORMdiscs,andDVDs. Compactdiscread-onlymemory(CD-ROM),asthenameimplies,isaread-onlymedium.CD-ROMsareeasyto duplicateanddistributeandarewidelyusedinlargepermanentdatabases,suchasforlibraries,realestatefirms, andfinancialinstitutions.Theyaresometimesusedformultimediaapplicationsandtodistributesoftware products.However,becauseoftheirlargercapacity—aminimumof4.7GB—digitalversatilediscread-onlymemory