CWSS Prelim P1 CP

COMMONWEALTHSECONDARYSCHOOLPRELIMINARYEXAMINATION2024 COMPUTINGPaper1(Theory) Name:___________________________________( ) Class:___________ SECONDARYFOUREXPRESS Wednesday28August2024SECONDARYFIVENORMALACADEMIC7155/01 1130–13302hours READTHESEINSTRUCTIONSFIRST Writeyourname,indexnumberandclassonalltheworkyouhandin.Writeindarkblueorblackpen.YoumayuseanHBpencilforanydiagramsorgraphs.Donotusestaples,paperclips,glueorcorrectionfluid. Approvedcalculatorsareallowed.Candidateswillansweronthequestionpaper. Answerallquestions. Thenumberofmarksisgiveninbrackets[]attheendofeachquestionorpartquestion.Youshouldshowallyourworking.Thetotalnumberofmarksforthispaperis80. ForExaminer’sUse Total 80 Thispaperconsistsof13printedpagesincludingthecoverpage.[Turnover

2 1 Acompanydealingwithdigitallocksusesastandardtouchscreenkeypadforitscustomerstoentertheir4-digitpincodestounlockthelocks.(a) Statetworeasonswhythepincodescanbeeasilystolen. 1....................................................................................................................... .......................................................................................................................... 2....................................................................................................................... .......................................................................................................................... [2] (b) Suggesttwowaystoprotectthepincodesfrombeingstolen. 1....................................................................................................................... .......................................................................................................................... 2....................................................................................................................... .......................................................................................................................... [2] Thecompanyprovidesanonlineserviceforcustomerswhoforgettheirpincodestologintothesystemtoresettheirpincodes. (c) Describethedifferencebetweenauthenticationandauthorisation. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................[2] (d) Explainwhyauthenticationisimportantforthisserviceandsuggestonemethodtoenhancetheauthentication. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................[2]

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4 2 DuringCOVID-19,aruraltownhastousevideo-conferencingserviceformedicalconsultation.Thisincludespatientswholiveinnearbymountainousareas. Describeapositive,negativeandethicalimpactofintroducingthisservice. Positive ..................................................................................................................................... ..................................................................................................................................... Negative ..................................................................................................................................... ..................................................................................................................................... Ethical ..................................................................................................................................... .....................................................................................................................................[3] 3 Asystemchecksifaplantisgrowinghealthilybycheckingthenumberofdaysithasgrownanditscorrespondingheight. (a) Identifyoneinputtothesystemanditsdatatype. ..........................................................................................................................[1](b) Identifyoneoutputtothesystemandwriteaprogramcodetoproducetheoutput. Output............................................................................................................... Programcode...................................................................................................[1] Thesystemisupgradedtocheckthehealthstatusofanynumberofplants. (c) Identifyaproblem-solvingtechniquethatcanbeusedtomodifytheprogramcode. ..........................................................................................................................[1]

5 4 (a) Completethetruthtableforthefollowinglogiccircuit. A B C WorkingSpace X 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 [3] (b) Drawalogiccircuitfortheexpression: X=(AORNOTB)NAND(NOTAANDC)

6 [5]5 Asoftwaredeveloperistaskedtodevelopacomputergameforteenagers. (a) Inthedevelopmentofhisgame,hefollowsasetofstages.Otherthanthewritingofcode,statetwootherstages. 1....................................................................................................................... .......................................................................................................................... 2....................................................................................................................... ..........................................................................................................................[2] (b) Theusersofthegamemusthaveausernameandpasswordtologintothegame. Thepasswordmustcontainatleast:● 12characters● 1lower-caseletter● 1upper-caseletter Writeanalgorithm,usingaflowchart,totakethepasswordasinput,repeatedly,untilitisvalidorinvalidforthreetimes.

7 [6](c) Completethetablebyidentifyingtwotypesofchecksusedin(b)andsuggestapasswordthatwilltesttheerrorconditionsofeachcheck. Typeofcheck Password [2] 6 Rahimissettingupacomputeratacomputershop. (a) Theowneradviseshimtopurchaseamulti-coreprocessorasadual-coreprocessorwillruntwiceasfastwhileaquad-coreprocessorwillrunfourtimesfasterthanasingle-coreprocessor. Statewhethertheowner’sstatementistrueandexplainyourreason. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................[2] (b) Rahimwantstopurchaseasecondarystoragedevice.Statetwofactorsthatheshouldconsiderwhilepurchasingasecondarystoragedevice. ........................................................................................................................... ...........................................................................................................................[2](c) Rahimdecidedtopurchaseasolidstatestoragedevice.Statetwoexamplesofsolidstatestoragedevices. ........................................................................................................................... ...........................................................................................................................[2]

8 7 Aprogramiswrittenforacashierofamini-mart.Theprogramallowstheusertoinputthepriceofitemsboughtbyacustomer,calculatestheamounttopayin