IGCSE Computer Studies Paper1a 2002

This question paper consists of 16 printed pages. SP (CW) S20762/1 © CIE 2002 [Turn over International General Certificate of Secondary Education CAMBRIDGE INTERNATIONAL EXAMINATIONS COMPUTER STUDIES 0420/1, 0421/1 PAPER 1 MAY/JUNE SESSION 2002 2 hours 30 minutes Candidates answer on the question paper. No additional materials are required. TIME 2 hours 30 minutes INSTRUCTIONS TO CANDIDATES Write your name, Centre number and candidate number in the spaces at the top of this page. Answer all questions. Write your answers in the spaces provided on the question paper. INFORMATION FOR CANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. Candidate Centre Number Number Candidate Name FOR EXAMINER’S USE2 0420/1 S02 1 Explain, using examples, the meaning of these computer terms. (a) multimedia ........................................................................................................................ ......................................................................................................................................... .....................................................................................................................................[2] (b) array ................................................................................................................................ ......................................................................................................................................... .....................................................................................................................................[2] (c) de-skilling ......................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (d) expert system ................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (e) verification ........................................................................................................................ ......................................................................................................................................... .....................................................................................................................................[2] 2 Describe two ways that a scanner could be used to transfer paper-based documents to files stored on a computer. 1 .............................................................................................................................................. ................................................................................................................................................. ................................................................................................................................................. 2 .............................................................................................................................................. ................................................................................................................................................. .............................................................................................................................................[2] For Examiner’s Use3 0420/1 S02 [Turn over 3 (a) State two advantages to businesses of using electronic funds transfer (EFT). 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (b) State two disadvantages to businesses of using EFT. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] 4 (a) State two advantages of using a high-level language rather than a low-level language for writing programs. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (b) Explain the difference between a compiler and an interpreter. ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] For Examiner’s Use4 0420/1 S02 5 A bank uses a mainframe computer. (a) State three tasks done by the operating system. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 3 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[3] (b) Describe how the bank’s data can be restored after systems failure. ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] 6 A microprocessor-controlled air-conditioning system has been installed in a museum. (a) (i) State a suitable input device. .................................................................................... (ii) State a suitable output device. ..............................................................................[2] (b) Describe the feedback loop which maintains the best conditions in the museum. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (c) State an advantage for the museum owners of having this system installed. ......................................................................................................................................... .....................................................................................................................................[1] For Examiner’s Use5 0420/1 S02 [Turn over 7 Weather satellites transmit images as coded radio signals to a computer on earth. (a) Give two ways software could be used to process these images. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (b) Suggest two advantages of using data from satellite systems rather than data from weather stations on the ground for forecasting the weather. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] For Examiner’s Use6 0420/1 S02 8 The following set of instructions can be used to control a robot which moves heavy boxes. The following set of instructions moves the robot forward 20 steps, turns the robot 90° anticlocckwis and moves the arms up 40 cm. Forward 20 Left 90 Up 40 (a) Write three more instructions so that the robot will return to its original state. ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[3] For Examiner’s Use Forward n Move forward n steps Backward n Move backward n steps Right d Turn clockwise d degrees Left d Turn anti-clockwise d degrees Up n Move the robots arms up n cm Down n Move the robots arms down n cm7 0420/1 S02 [Turn over (b) A procedure (subroutine) called BELT exists to take one box and put it on a conveyor belt. Write an algorithm, using this procedure, to put 50 boxes on the conveyor belt. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[3] For Examiner’s Use8 0420/1 S02 9 Errors can occur in data when it is being transmitted. A zero can be changed to a one and a one can be changed to a zero. A method of checking the data is to write 1 in bit position 7 if there is an odd number of 1’s in the other 7 bits, otherwise write 0 in bit position 7. For example the following bit pattern has a 1 in bit position 7 as the other bits contain an odd number of one’s. Bit position Data (a) Complete the bit pattern below by writing the bit which should be in position 7. [1] (b) In order to give a better chance of errors being discovered, a block of data can have vertical as well as horizontal checks. Complete the table by inserting the bits that should be on the bottom row. Bit position [2] (c) Suggest a reason why a bit could have changed when the data were transmitted. ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[1] For Examiner’s Use 7 6 5 4 3 2 1 0 1 0 0 1 1 1 0 0 7 6 5 4 3 2 1 0 1 0 1 1 1 0 0 7 6 5 4 3 2 1 0 1 0 1 0 0 0 0 0 1 0 0 1 1 1 0 0 1 1 1 1 1 1 1 1 0 1 0 1 0 1 0 1 0 0 0 0 1 1 0 0 0 0 0 1 0 0 0 1 0 1 09 0420/1 S02 [Turn over 10 The following spreadsheet shows the results of two tests. The cells D2:D6 each contain a formula. (a) Write down a cell which should contain (i) a label ....................................................................................................................... (ii) a number ...............................................................................................................[2] (b) Suggest a formula that could be in D2 to calculate the average mark. .....................................................................................................................................[1] (c) Describe how the formula in D2 can be copied into the range of cells D3:D6. ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (d) Describe how the results for TEST 1 can be displayed in descending order. ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (e) A bar chart is needed to compare the average marks for each student. Write down the range of cells needed to produce the chart. ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] For Examiner’s Use A B C D E TEST 1 TEST 2 AVG MARK PASS 1 out of 100 out of 100 2 M DAVIES 82 68 75 YES 3 J GRIFFITHS 48 72 NO 4 S HARRISON 98 98 YES 5 M KHAN 88 62 YES 6 I PATEL 70 80 YES10 0420/1 S02 11 Part of a holiday file is shown below. The following codes represent the meals. MEALS RO – room only BB – bed and breakfast HB – half board FB – full board (a) Complete the table below to show the data type and field size for each field. [2] (b) State two reasons why the MEALS data have been coded. 1 ...................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... .....................................................................................................................................[2] (c) Suggest two more fields that could be used in this file. 1 ...................................................................................................................................... 2 ..................................................................................................................................[2] For Examiner’s Use BOOKING NO MEALS NIGHTS HOTEL PRICE ($) BK0042 RO 7 REGENT 250 BK0043 FB 5 SAVOY 400 BK0044 HB 6 BROWNS 350 BK0046 FB 7 SEAVIEW 375 BK0048 BB 10 HILL TOP 295 BK0050 HB 7 VALLEY 475 FIELD NAME DATA TYPE FIELD SIZE BOOKING NO MEALS NIGHTS HOTEL PRICE ($)11 0420/1 S02 [Turn over (d) The following search condition is input (MEALS = “RO”) OR (PRICE ($) > 350). (i) Write down the output using the BOOKING NO only. .................................................................................................................................. .................................................................................................................................. ...............................................................................................................................2] (ii) Write a similar search condition which will display the holidays which are more than 7 nights and cost $450 or more. ...............................................................................................................................2] (e) Describe the processing and output when a customer books a holiday. Processing ....................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 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(a) Explain why a modem is needed to communicate with the ISP. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (b) Describe two ways that the ISP fileserver will check that the salesperson is an authorised user. 1 ...................................................................................................................................... ......................................................................................................................................... 2 ....................................................................................................................................... .....................................................................................................................................[2] (c) Describe three services, other than e-mail and connection to the internet, that the ISP may offer. 1 ...................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... 3 ...................................................................................................................................... .....................................................................................................................................[3] (d) Explain what the Internet is. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] For Examiner’s Use13 0420/1 S02 [Turn over 13 A small business has decided to change from a manual wages system to a computerised wages system for producing the employees’ pay. (a) State three stages in the analysis of the existing system. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 3 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[3] (b) State two advantages for the business of writing the program instead of buying a software package. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] (c) State two types of test data that should be used to test the program. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] For Examiner’s Use14 0420/1 S02 (d) State two items that should be included in the program’s documentation. 1 .............................................................................................................................................. ................................................................................................................................................. 2 .............................................................................................................................................. .............................................................................................................................................[2] 14 A computer is used in a hospital to monitor and control a patient’s condition. (a) State an item of data that could be input. ......................................................................................................................................... .....................................................................................................................................[1] (b) Describe the processing done by the computer. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[3] (c) State an output from the system. ......................................................................................................................................... .....................................................................................................................................[1] For Examiner’s Use15 0420/1 S02 [Turn over 15 A doctor is planning to store patient records on a computer system. (a) State three Data Protection Rules that the doctor should obey. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 3 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[3] (b) Describe two possible effects if the doctor does not obey the Data Protection Rules. 1 ...................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... 2 ...................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] For Examiner’s Use16 0420/1 S02 16 Using pseudo code or otherwise, write an algorithm which will take information about each transaction at a supermarket till, calculate and output • the number of sales, • the number of refunds, • the total amount of money in the till. ................................................................................................................................................. ................................................................................................................................................. 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