Cambridge IGCSE Computer Studies 0420 — 2007 Oct/Nov Paper 1 · Variant 1

This document consists of 20 printed pages. IB07 11_0420_01/5RP © UCLES 2007 [Turn over *1813431273* For Examiner's Use UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMPUTER STUDIES 0420/01 Paper 1 October/November 2007 2 hours 30 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. No marks will be awarded for using brand names of software packages or hardware. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. www.XtremePapers.com

2 © UCLES 2007 0420/01/O/N/07 For Examiner's Use 1 Explain, with examples, the following five computer terms: (a) byte [2] (b) CD-ROM [2] (c) interrupt [2] (d) buffer [2] (e) virtual reality [2]

3 © UCLES 2007 0420/01/O/N/07 [Turn over For Examiner's Use 2 Give two differences between high level languages and low level languages. 1 2 [2] 3 (a) Give three of the elements that make up an Expert System. 1 2 3 [3] (b) Give an example of the use of an Expert System. [1]

4 © UCLES 2007 0420/01/O/N/07 For Examiner's Use 4 Online banking using the Internet is now increasing. (a) Give one advantage to the customer of using online banking. [1] (b) Give one advantage to the bank of providing online banking. [1] (c) Online banking has an impact on society as a whole. (i) Give one positive effect. (ii) Give one negative effect. [2] (d) Describe two concerns people might have regarding online banking. 1 2 [2]

5 © UCLES 2007 0420/01/O/N/07 [Turn over For Examiner's Use 5 (a) (i) Name one method used to protect data against unauthorised access. [1] (ii) Name one method used to protect data in a file from being understood when an unauthorised person has gained access to the file. [1] (b) State three items that could be included as part of a Data Protection Act. 1 2 3 [3] 6 Thular is doing his IGCSE coursework on the school’s local network. He would like to continue this work on his computer at home. Name and describe two methods that he could use to do this. Method 1 Description Method 2 Description [4]

6 © UCLES 2007 0420/01/O/N/07 For Examiner's Use 7 A company has decided to publish its Science books on the Internet rather than produce a series of paper-based books. Give three reasons why a company might choose to do this. 1 2 3 [3] 8 Give three tasks carried out by systems software. 1 2 3 [3]

7 © UCLES 2007 0420/01/O/N/07 [Turn over For Examiner's Use 9 A multi-national company has decided to use video-conferencing facilities rather than the traditional approach of everyone meeting at one location. (a) What is meant by video-conferencing? [2] (b) Give three advantages of using video-conferencing. 1 2 3 [3] (c) Using emails is another method of communication. What advantage has this method compared with video-conferencing? [1]

8 © UCLES 2007 0420/01/O/N/07 For Examiner's Use 10 A systems analyst has been asked to replace an existing manual filing system with one which is computer-based. (a) The paper-based files need to be converted into an electronic format. Describe two ways this could be done. 1 2 [2] (b) When the system is implemented, the systems analyst will provide documentation. One type of documentation shows how the new system will work. (i) Name this type of documentation. [1] (ii) Give two items contained in this documentation. 1 2 [2]

9 © UCLES 2007 0420/01/O/N/07 [Turn over For Examiner's Use (c) Another type of documentation is to allow future programmers to update or maintain the system. (i) Name this type of documentation. [1] (ii) Give two items contained in this documentation. 1 2 [2] (d) Name two methods of implementing the system. For each method, give a reason for using it. Method 1 Reason 1 Method 2 Reason 2 [4]

10 © UCLES 2007 0420/01/O/N/07 For Examiner's Use 11 Majid lives in Cairo but often travels to Tokyo, Mumbai and Washington. A flow chart has been written so he can work out the local time in these three places. START STOP H = H + 7 M = M + 0 Input time in hours (H) and minutes (M) Input place Output H, M H = H + 3 M = M + 30 H = H – 7 M = M + 0 Is place=Tokyo Is place=Mumbai Is place=Washington Is place=End Yes Yes Yes No No No No Yes

11 © UCLES 2007 0420/01/O/N/07 [Turn over For Examiner's Use (a) What output would be produced from the following input? Input Output place hours (H) minutes (M) H M Tokyo 11 15 Mumbai 15 10 [2] (b) What problem would occur if place = Mumbai and H = 15 and M = 30? [1] (c) What problem would occur if place = Washington and H = 4 and M = 0? [1]

12 © UCLES 2007 0420/01/O/N/07 For Examiner's Use 12 A company checks its electrical equipment every three years. To help make sure that every item is checked at the correct time, the company has decided to put barcodes on the equipment. The barcode contains: • type of equipment (e.g. monitor) • location (e.g. Room 507) Every time equipment is checked, the barcode is scanned and the data stored on a file. (a) Give one other piece of information that should be on the barcodes. [1] (b) Give one example of other information that should be stored on the file itself. [1] (c) Give two advantages of this system rather than using sticky labels on the equipment marked, for example, “Do not use after May 2007”. 1 2 [2] (d) Describe another application where barcodes could be used. [1]

13 © UCLES 2007 0420/01/O/N/07 [Turn over For Examiner's Use 13 A robot is used in a car factory to spray car bodies. (a) How does the robot know which parts of the car body are to be sprayed? [1] (b) How would the robot know that the car was in the correct position to be sprayed? [1] (c) The robot needs to be able to detect a range of possible problems (such as the car not being in the correct position). Name another possible problem and explain how it could be overcome. Problem Solution [2] (d) Give another application of robotics. [1] (e) Give one advantage of using robots instead of manual labour. [1]

14 © UCLES 2007 0420/01/O/N/07 For Examiner's Use 14 The following spreadsheet shows how the value of certain items of computer equipment changes over time. Cells B8 and C2:E8 contain formulae. A B C D E 1 Equipment Value ($) Year 1 Value ($) Year 2 Value ($) Year 3 Value ($) Year 4 2 PC System 1600 800 400 200 3 Laptop Computer 2000 1000 500 250 4 Laptop Case 80 40 20 10 5 PC Cover 16 8 4 2 6 Printer 320 160 80 40 7 Scanner 120 60 30 15 8 Total value ($) 4136 2068 1034 517 (a) State a cell that contains a data item. [1] (b) Give a formula which could be in cell B8 to calculate the total value of the equipment in Year 1. [1] (c) Each year the value of the equipment is halved. State a formula that could be in cell C2 to calculate value of a PC System in Year 2. [1] (d) State all the cells where the values change automatically if the value in cell B4 is changed to 60. [2]

15 © UCLES 2007 0420/01/O/N/07 [Turn over For Examiner's Use (e) The following chart has been produced from the spreadsheet. Value ($) Year 1 Value ($) Year 2 Value ($) Year 3 Value ($) Year 4 4500 4000 3500 3000 2500 2000 1500 1000 500 0 Which cells must have been selected to create and label the chart shown? [2]

16 © UCLES 2007 0420/01/O/N/07 For Examiner's Use 15 A school Science department is going to use a database to record details about its equipment. (a) Give two advantages of using a computer system rather than a manual filing system. 1 2 [2] (b) Part of the database is shown below: Equipment Code No Quantity in Stock Need to re-order? Supplier Name Price ($) Stock Value ($) Beaker 01043 25 Y Labquip 1.04 26.00 Test tube 01051 200 N Labquip 0.40 80.00 Clamp stand 01065 51 N Anglera 3.25 165.75 Tongs 01151 23 Y Anglera 0.55 12.65 Spatula 01222 62 N Anglera 0.66 40.92 Flask 01341 15 Y Labquip 1.70 27.50 (i) As data is entered it needs to be verified. Describe one way this could be done. [1] (ii) Data also needs to be validated. Using fields from the database as examples, describe two different validation checks which could be performed on the data. Name of field Validation check Name of field Validation check [2]

17 © UCLES 2007 0420/01/O/N/07 [Turn over For Examiner's Use 16 (a) Fuel economy for a car is found using the formula: Distance Travelled (km) Fuel Economy = Fuel Used (litres) What would be the Fuel Economy of a car travelling 40 km on 10 litres of fuel? [1] (b) The Fuel Economy for 1000 cars is to be calculated using the formula in Question 16(a). Write an algorithm, using pseudocode or otherwise, which inputs the Distance Travelled (km) and the Fuel Used (litres) for 1000 cars. The Fuel Economy for each car is then calculated and the following outputs produced: • Fuel Economy for each car • average (mean) Fuel Economy for all of the cars input • the best Fuel Economy (i.e. highest value) • the worst Fuel Economy (i.e. lowest value) [6]

18 © UCLES 2007 0420/01/O/N/07 For Examiner's Use 17 The following flowchart shows how a payroll transaction file is used to produce company pay slips. Update Master File Produce Reports Payroll transaction file Payroll master file Sorted transaction file Validated transaction file Management reports Payroll updated master file

19 © UCLES 2007 0420/01/O/N/07 [Turn over For Examiner's Use (a) Show on the diagram where SORTING is carried out and where VALIDATION is carried out. [1] (b) Show on the diagram two places where ERROR REPORTS are produced. [1] (c) Show on the diagram where PAYSLIPS are produced. [1] (d) The transaction file was created using batch processing. Why was it not appropriate to use real time processing? [1] (e) Name another application which uses batch processing. [1]

20 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. © UCLES 2007 0420/01/O/N/07 For Examiner's Use 18 Monitoring of patients’ vital signs (e.g. heartbeat) in a hospital is done automatically using sensors and computer hardware. Readings are shown on a screen both as a graph and as numbers. (a) Why are readings shown in both graphical and numerical form? (b) When the heartbeat is being monitored, how does the system decide if the doctor/nurse needs to be warned of an abnormal reading? [1] (c) Give two advantages of using this type of automatic monitoring. 1 2 [2] (d) How does this monitoring system differ from a control system? [1] [2]

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2007 question paper 0420 COMPUTER STUDIES 0420/01 Paper 1, maximum raw mark 100 This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began. All Examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. Mark schemes must be read in conjunction with the question papers and the report on the examination. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2007 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses. www.XtremePapers.com

Page 2 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 1 (a) byte any two points from: fixed number of bits/8 bits represents a character unit of memory/storage e.g. 11010001 [2] (b) CD-ROM any two points from: (secondary/portable) storage medium can be read only (memory) cannot change data e.g. used to store programs/data/pictures/films, etc. [2] (c) interrupt any two points from: a signal/request generated by a device/program causes a break in execution of a program/stops the program e.g. printer out of paper, pressing break key [2] (d) buffer any two points from: temporary store/memory allows speed of CPU/devices to be matched to hold data being transferred between peripherals and CPU e.g. pages stored waiting to be printed [2] (e) virtual reality any two points from: 3D world computer simulation needs special input devices to interact – (data) goggles/gloves e.g. design of chemical plants [2] 2 Any two differences from: high level low level portable problem-orientated machine-orientated close to English can be difficult to read/understand one-to-many relationship one-to-one relationship easier to debug/change/upgrade needs assembler needs compiler/interpreter [2]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 3 (a) Any three points from: knowledge base rule base inference engine (suitable) input/output interface/shell [3] (b) Any one example from, e.g. mineral/oil prospecting tax/financial calculations chess diagnostics speech recognition [1] 4 (a) Any one advantage from, e.g. can bank from home (disabled) customers do not need to go to bank no need to queue at bank can make payments/check accounts from home banking 24/7 can bank with any bank in the world better interest rates available [1] (b) Any one advantage from, e.g. no need to have offices (in every town) increased banking profits (less overheads) larger customer base (worldwide) fewer staff required [1] (c) (i) Any one positive effect from, e.g. less pollution less traffic (ii) Any one negative effect from, e.g. less (social) interaction job losses/closing down of branches inner cities become “ghost towns” increase in online fraud/hacking [2] (d) Any two from: fraud viruses bogus sites loss of personal contact with the bank [2]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 5 (a) (i) Any one from: passwords/biometrics user id/access rights firewall removable storage media physical protection [1] (ii) encryption [1] (b) Any three from: data must be kept up-to-date data must be accurate data must be obtained/used legally/lawfully data must be adequate, relevant and not excessive data must only be used for the stated purpose data must not be kept longer than necessary data must be kept secure data must be transferred only to countries that offer adequate data protection data holder must register with DPC data subjects have the right to have incorrect data removed/changed data subjects have a right to see a copy of their own data in an understandable form [3] 6 1 mark for each method + 1 mark for each description/reason email work home – use of attachments – use of home email address/account save on floppy disk/CD-R, etc. – would need same devices at home – portable therefore easy to take home print out work – have to type information in again – need to scan in print-outs access work from internet – need internet access at home – needs to access school website [4] 7 Any three reasons from: easier/faster to update books (science is always changing) fewer printing/distribution/production costs/no paper costs easier/faster distribution no need to find storage for the books can have links to other sites easier/faster to search for a topic (rather than search an index) possible to include sound } multi- possible to include animation (video) } media possible to include interaction [3]

Page 5 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 8 Any three tasks from: file management input/output control spooling memory management multitasking/JCL/batch processing multiprogramming handles interrupts error reporting/handling security, e.g. virus checking interfaces with user/WIMP environment loads/runs programs processor management user accounts utilities [3] 9 (a) Any two points from: meeting between 2 or more participants at different sites using computer network/WAN/internet to transmit audio and video data each participant has a video camera/webcam, microphone and loud speakers images appear in real time on participants screen(s) [2] (b) Any three points from: no need for office space saves on travelling time saves on travelling costs/hotel costs/conference room costs can have meetings at short notice safer – no need to travel to venues disabled staff can work from home/no need to travel to venue [3] (c) Any one advantage from: time differences do not cause problems can send attachments fewer language difficulties (auto translators) emails can be read later [1]

Page 6 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 10 (a) Any two ways from: scan in the documents type in the documents (using a keyboard) using voice recognition [2] (b) (i) user documentation/guide [1] (ii) Any two from, e.g. how to load software how to run software how to log in and out how to save files screen layouts sample runs troubleshooting guide hardware requirements software requirements print formats how to print [2] (c) (i) technical documentation/systems guide [1] (ii) Any two from, e.g. program listing flowcharts, etc. list of variables/data dictionary file structures purpose of the system/program screen layouts print formats hardware requirements software requirements sample runs (DO NOT allow the same marking point in parts (b) and (c)) [2] (d) 1 mark for each method + 1 mark for each reason parallel running – allows back up in case of failure direct changeover/big bang – faster to implement/saves on wages phased implementation – can iron out problems before changing pilot running – system trialled by one section before total implementation [4]

Page 7 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 11 (a) H M 18 15 18 40 [2] (b) Any one point from: M would become 60 and should be 0 for correct time H would become 18 and should be 19 for correct time [1] (c) Would get a negative answer for H [1] 12 (a) Any one point from: equipment id date of purchase [1] (b) Any one point from: date equipment checked time equipment checked person who last checked the equipment passed/failed maintenance history [1] (c) Any two advantages from: automatic checking is now possible can easily bring up history of device not as easy to alter results in improved safety more accurate no need to change the sticky label [2] (d) Any one from, e.g. stocktaking supermarket tills libraries [1]

Page 8 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 13 (a) Any one from: “taught” by paint sprayer and robot remembers tasks actions programmed in directly [1] (b) Any one from: use of sensors to detect car presence of car fed back to robot’s control system [1] (c) 1 mark for fault condition + 1 mark for solution out of paint – level sensor in paint reservoir software fault – self diagnostics hardware fault – self diagnostics problem with external conditions – give warning and wait for human to correct and reset [2] (d) Any one from, e.g. space exploration underwater exploration work in dangerous chemical/nuclear plants toys manufacturing/assembling [1] (e) Any one from: cheaper – no wages consistency work 24/7 (do not need breaks, holidays) can work in dangerous conditions [1] 14 (a) Any one in the range: A2:B7 [1] (b) SUM(B2:B7) Or B2 + B3 + B4 + B5 + B6 + B7 [1] (c) B2/2 [1] (d) C4, D4, E4, C8, D8, E8, B8 –1 for each error or omission [2] (e) B1:E1 B8:E8 [2]

Page 9 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 15 (a) Any two advantages from: easier to know when to re-order automatic re-ordering easier/faster to update easier/faster to access information more up to date stock levels fewer mistakes takes up less storage space [2] (b) (i) Any one from: double entry visual check/comparison with original [1] (ii) Any two checks from (accept examples): (two different checks must be given but the same field can be given twice) equipment – character check, length check code – length check, character check, check digit quantity – range check, character check need to re-order – character check, length check, Boolean check supplier name – character check, length check price – format check, range check stock value – range check, character check [2] 16 (a) 40/10 = 4 [1] (b) general marking points initialising best and worst to sensible values correct loop for 1000 cars correct use of calculation given in part (a) output economy for each car inside loop determining best economy determining worst economy calculating mean economy for all cars input data and output all three results (only award mark if some form of processing done) [6] sample program total = 0, count = 0, best = 0, worst = 1000 1 mark repeat 1 mark input litres, distance economy = distance/litres 1 mark print economy 1 mark if economy > best then best = economy 1 mark if economy < worst then worst = economy 1 mark total = total + economy count = count + 1 until count = 1000 average = total/1000 1 mark print average, best, worst 1 mark

Page 10 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 17 (a), (b), (c) [3] Payroll transaction file Validated transaction file Update Master File Produce Reports Payroll master File Sorted transaction File F Management reports VALIDATION SORTING ERROR REPORTS ERROR REPORTS PAYSLIPS (1 mark) (1 mark) for both error reports (1 mark)

Page 11 Mark Scheme Syllabus Paper IGCSE – October/November 2007 0420 01 © UCLES 2007 (d) Any one point from: no need for immediate/fast response data collected about wages over a period of time not needing processing straight away [1] (e) Any one example from, e.g. stock control (NOT automatic) billing systems payroll [1] 18 (a) Any two points from: graphics allows trends to be shown figures/numbers are easier to read figures/numbers show actual values both methods are used for different purposes [2] (b) compare new value with stored value [1] (c) Any two advantages from: do not need nurse/doctor to be there all the time quicker to pick up problem with patient’s condition easier to obtain trends/analysis more accurate/less likely to make mistakes [2] (d) Any one point from: no output influencing the input no equipment controlled (e.g. valves) pure monitoring – makes no changes to system being monitored [1]