1. Computers are used in supermarkets at point of sales terminals. When paying for goods the Customer inserts the bank card into the chip reader.

(a) Identify three items of data contained in the chip on a bank card.

Three from:

Card numberPINExpiry dateType of card/issuerSecurity number

(b) Describe three checks that would be carried out using information on the card beforethe bank is asked to authorize the transaction.

Card is valid/card number existsCard is in datePIN entered matches that on cardChecks if card is stolen

(c) Describe five steps which would be carried out by the computers at the supermarketand at the customer’s bank to complete the transaction.

Five from:Customer bank contactedBank looks up customer account numberChecks available balanceChecks daily (card) limitIf insufficient funds then transaction is rejectedIf sufficient funds then transaction is authorizedMoney deducted from customer accountMoney credited to supermarket account

2. Identify three items of test data which could be used with the Price field giving reasonsfor your choice.

Any three matched pairs fromA value between 0 and 20This is normal data and should be accepted by the system0 or 20This is extreme data and should be accepted by the systemAny number above 20 or textThis is abnormal data and should be rejected by the system

3.Describe three uses of modeling.

SimulationsMathematical modelsScientific modelsCivil engineering modelsFinancial modelsFlight/pilot simulation/trainingLarge scale chemical experimentsDesign of fairground ridesTraffic controlBuilding fire simulation

4. Give two reasons, other than reducing timescale, why computer models aresometimes used rather than the real thing.

Some situations are/real thing might be dangerous/model is less dangerousCost of building real thing may be expensiveReal thing may waste raw materials/natural resourcesEasier to change data/variablesCosts less to change data/variablesThe real thing may be impossible to access/createReal thing may be on too vast a scaleExtremes which can’t be tested in real life can be tested using models.

5. Describe how the supermarket’s computer uses a check digit to check that data hasbeen entered correctly.

Computer calculates check digit from numbers in bar code numberCompares calculated check digit with that recorded in bar code numberIf same, proceeds with transaction, otherwise sounds warning signal/issues error message

6.The supermarket computer can automatically re-order items when the supermarket isrunning low on stock.Describe this process, using the example databases above when two more packets ofKollege Corn Flakes pass through the checkout.

Every time a product is bought, number in stock reduces by 1Number in stock of Kollege Corn Flakes falls to 150Compare number in stock with Re-order levelIs equal so needs re-ordering

Kollege Corn Flakes now needs re-orderingRead off re-order quantity (which is 50)Read off supplier code L93512Use suppliers’ databaseLookup supplier code (L93512)Read off supplier’s name, address - Lu Chen, Kinshasa Highway, Box 41324Print off re-order requestPrint off address label

7.Name and describe three types of test data which are used when testing a system.

Normal data – data within a given range/appropriate for that data typeAbnormal data – data outside the range/of the wrong data typeExtreme data – data on the boundaries of the rangeLive data – data that has been used in the previous/existing system

8. Explain why authentication techniques are necessary.

Authentication techniques such as user names and passwords identify the user to thesystemWithout authentication anybody would be able to access dataHackers would be able to amend/delete data without being preventedWould have to rely on other methods such as firewalls to prevent unauthorised access.

9.Customer data is encrypted. Explain what encryption is and why it is used.

Causes data to be scrambled/encodedRequires an encryption key/software to encryptRequires a decryption key/encryption software to decryptResults in data which is not understandable/readableProtects sensitive data…… from being understood if it falls in to the wrong hands

(b) Name and describe the most appropriate validation check which would be carried outon the Race_ID field.

Format/Picture [1]Checks the data is of the format beginning with a letter and ending in three digits and is onlyfour characters long.

10. Anya wants to have a system which will make it easy to enter data.Describe five features of a well designed input screen.

Appropriate spacing for each fieldButtons to go forward/backwardsScreen filled/not too much white spaceDrop down lists to choose an option (such as race length)Button to save data/submit/acceptClearly defined input area for each fieldTick boxes/radio buttons to enter choicesAn easy to read font/font sizeA sensible font colour/background colourEasy to follow instructions for completing screen/help iconNo overlapping of items

11. Discuss the advantages and disadvantages to banks of using internet banking.

Advantages:Fewer bank tellers so less paid out in wagesLess actual cash handled – fewer robberiesHave access to a wider customer baseFewer branch offices needed – less spent on rates/rent/utilitiesLess money spent on security staffDisadvantagesInitial cost of hardware/software is expensiveNeed to retrain staffLoss of customers/more difficult to sell other services due to lack of personal touchCosts of system maintenance

12. Describe batch processing of data, using the processing of bank cheques as anexample.

Data/cheques are collected togetherduring the course of the dayData/cheques are then processed all at onceData/cheques are processed overnightDank accounts updated following morningNo human intervention

13. Explain why the booking of airline tickets using batch processing would not be a good idea.

It might lead to double bookingCustomer would not be sure booking has been successfulWould take a long time to receive confirmation/ticketProcessing would take a long time…… would cost company money

14.Explain the differences between parallel running and direct changeover as ways ofimplementing the new database.

Direct changeover – new system replaces existing system immediately/overnightParallel running – new system runs alongside/together with existing systemParallel running – there is always the old system to fall back on in the event of the newsystem failing/information is not lost/always a second copy/Direct changeover – if things

go wrong lose all data/old system is not availableDirect changeover – benefits are immediately availableParallel running is more expensive to implement than direct changeover........more expensive as two sets of workers have to be employedDirect changeover – less likelihood of errors as system will have been fully testedDirect changeover is a quicker method of implementation than parallel runningDirect changeover – training is more difficult to organiseParallel running – training can be gradual

15.Explain why it is necessary to carry out validation even though the data has beenverified.

Source document may contain errorsVerification only checks that data is copied correctlyVerification does not check if data is reasonable/sensibleA correct explanation of an example of one validation check

16. A supermarket has a number of EFTPOS terminals.Explain what is meant by EFTPOS and how such a system works.

Electronic Funds Transfer at Point of SaleEnables payment for goods at a checkout using credit/debit cardsGoods are purchased and bill is calculatedCustomer inserts card into chip readerCard is checked for validity/reported stolenPIN is enteredPIN is compared with that stored on the chipIf PIN is OK/verified transaction is authorisedIf not, customer is asked to re-enter PINSupermarket computer contacts customer’s bankChecks if sufficient fundsIf sufficient funds, transaction is completed/if not, transaction is rejectedAmount deducted from customer’s bank accountAmount credited to supermarket’s bank accountThe supermarket EFTPOS terminal produces a receipt17. Car mechanics often use an expert system to help them with their work in diagnosing carengine faults.Describe how this system would work.

Data is read by sensors/downloaded from onboard computer/entered using keyboard/touchscreen/answers to questions are typed inUses interactive interface/Asks questions...........based on previous responsesExpert system analyses dataInference engine compares dataCompares data with that held in the knowledge base............... using rules base

Matches are foundSystem suggests possible faults/solutions

18. A house has a microprocessor controlled central heating system.

(a) Describe the use of the following input devices in such a system.KeypadSensor

Keypad to input required temperatureSensor to input current temperature of the room

(b) Describe how the microprocessor would use the data from these devices to control thesystem.

Microprocessor stores required temperature as preset valueCompares temperature from sensor to pre-set temperatureIf temperature is lower than preset value microprocessor sends a signal to turn heater onIf higher than preset value microprocessor sends a signal (to the actuator) to turn heater offIf values are equal microprocessor does nothingWait set period of time before looping

19. A customer uses a bank card to purchase a product at a supermarket checkout. Thecheckout operator uses a number of devices to input data about the customer and theproduct.Identify four of these input devices and for each one describe a different item of data thatwill be input.

Chip reader

Bank/credit card account information/supermarket codeBar code readerInformation from a product label/product identity numberElectronic scalesWeight of an itemTouch screenIdentification of productNumber padBar code number when bar code reader cannot read bar code/the number of itemsMagnetic stripe readerInformation about the customer

20. Boris will provide two types of documentation when the system is implemented.Name each type of documentation and for each one give two items which would beincluded.

Technical [1]Two from:Program listingProgramming languageFlowchart/algorithmList of variablesFile structurePurpose of the system/programInput format or exampleOutput format or exampleHardware requirementsSoftware requirementsSample runs/test runsKnown bugs/possible errorsValidation rulesLimitations of the system [2]User [1]Two from:How to load software/install/run softwareHow to save a fileHow to searchHow to sortHow to printHow to add recordsHow to delete/edit recordsPurpose of the system/program (only if not mentioned in technical documentation)Input format or example (only if not mentioned in technical documentation)Output format or example (only if not mentioned in technical documentation)Hardware requirements (only if not mentioned in technical documentation)Software requirements (only if not mentioned in technical documentation)Sample runs (only if not mentioned in technical documentation)Error messages (only if not mentioned in technical documentation)

Error handlingLimitations of the systemTutorialsTroubleshooting guide/Contact details/help line/FAQ

21. Spreadsheets are often used to produce computer models. There are however, otherforms of models such as simulations.Explain, using air pilot training as an example, what is meant by simulation

Creating a model of a real system (such as a cockpit)……in order to study the behaviour of the system/pilot reactionsIs able to predict/react to the behaviour of the system or pilotThe cockpit simulation has all the controls normally found in an actual cockpitCreating models of situations that pilots might meet in real life/Creates whatif scenarios

22. Robots are now used on many car production lines.Discuss the benefits and drawbacks to the car company of using robots.

Car production is more consistent/robots produce the same standard every timeCost – once bought they do not have to be paid/fewer employees so lower costs/don’t have topay robots wages/lower running costsNo industrial disputesGreater productivityGreater accuracy/robots are more accurateCan work in hazardous/extreme conditions/can lift heavier loadsRobots don’t take breaks/can work 24 hours a day 7 days a week/can work continuously

Robots have to be reprogrammed when there is a small change/can’t think for themselvesRobots need programming in order to be adaptableExpensive start up costs – redundancy paymentsExpensive start up costs – have to spend money on training workers to use robotsExpensive start up costs – buying of robots/programming of robotsComputer crash would halt productionMaintenance/repair costs can be expensive

23. A group of car mechanics wants to have an expert system to help them with their work indiagnosing car engine faults.Describe how such a system would be created.

Data is gathered/collected from expertsKnowledge base is designed/createdA structure to relate each item in the database / knowledge base is createdAn interrogation technique to access the data is createdA user interface/method of displaying the results/method of inputting data/ input screen/outputscreen is designed/createdThe inference engine is designed/createdThe rules base is designed/createdThe system is tested

24. Describe online processing of data, using the booking of airline tickets as an example.

User/customer is in direct contact with the main computer/CPUAppears that nobody else can access system at that point/processing is almost immediateComputer asks customer for details of flightComputer asks for personal details of passengersComputer searches for matching flightsComputer may display list of seats availableComputer may ask customer to select a seat(Customer selects seat from those available and) computer flags seat as bookedComputer asks customer to complete payment detailsComputer checks details are valid by communicating with customer’s bankComputer checks if sufficient fundsAirline’s database is updated immediatelyNumber of seats available reduces by number bookedPrevents double bookingConfirmation/e-ticket may be sent to customer by email

25. A head teacher wishes to publicise school activities to make his school better known in theneighbourhood. He could do this by using the school’s website or producing a magazineusing DTP to be delivered by hand.Discuss the advantages and disadvantages of each method.

Advantages of DTPCan be sure every local family gets to see itNot everybody has a computer/internet/modemCan read it anywhere/not limited to where computer is.Disadvantages of websiteCan’t be sure every local family gets to see itNot everybody has a computer/internet/modemCan’t read it anywhere/ limited to where computer is.Disadvantages of DTPTakes time to physically distribute by handMight need to pay somebody to distribute by handCosts of ink/paper/printingNot as easy to updateNot interactive/hyperlinksNo animation/videoNo soundAdvantages of websiteNo costs of ink/paper/printingEasier to updateInteractive/hyperlinksAnimation/videoSound

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