Cambridge IGCSE Computer Science Paper 1 PDF February/March 2024

Cambridge IGCSE™ * 5 0 1 5 4 0 7 3 5 7 * COMPUTER SCIENCE 0478/12 Paper 1 Computer Systems February/March 202...

Cambridge IGCSE™ * 5 0 1 5 4 0 7 3 5 7 * COMPUTER SCIENCE 0478/12 Paper 1 Computer Systems February/March 2024 1 hour 45 minutes You must answer on the question paper. No additional materials are needed. INSTRUCTIONS Answer all questions. Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. Write your name, centre number and candidate number in the boxes at the top of the page. Write your answer to each question in the space provided. Do not use an erasable pen or correction fluid. Do not write on any bar codes. Calculators must not be used in this paper. INFORMATION The total mark for this paper is 75. The number of marks for each question or part question is shown in brackets [ ]. No marks will be awarded for using brand names of software packages or hardware. This document has 16 pages. Any blank pages are indicated. DC (DE) 327909/3 © UCLES 2024 [Turn over  2 1 Computers represent different types of data in binary. (a) Tick (✓) one box to show the reason why computers use binary to represent data. A Computers only allow 1s and 0s to be entered. B Computers are made of switches and gates that can only be on or off. C Binary does not need to be converted into other forms of data to be displayed. D Both computers and humans can quickly process binary data. (b) One form of data is characters. The American standard code for information interchange (ASCII) denary number for the character ‘N’ is 78. (i) Tick (✓) one box to identify the ASCII denary number for the character ‘Q’. A 81 B 80 C 79 D 77 (ii) Give the binary number for the ASCII denary number for ‘N’...................................................................................................................................... Working space................................................................................................................................................................................................................................................................................................................................................................................................................................. (iii) Explain how the word ‘RED’ is represented using a character set....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... © UCLES 2024 0478/12/F/M/24  3 (c) Sound can be represented as binary. (i) Explain why recording sound with a higher sampling resolution creates a more accurate recording....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (ii) Give one other way that the accuracy of a sound recording can be improved................................................................................................................................................................................................................................................................................. © UCLES 2024 0478/12/F/M/24 [Turn over  4 2 A computer has a central processing unit (CPU). The CPU includes the registers: Program counter (PC) Memory address register (MAR) Memory data register (MDR) Accumulator (ACC) Current instruction register (CIR). (a) The table contains five statements about the role of registers in the fetch–decode–execute cycle of a CPU. Letter Statement A PC stores the address of the next instruction to be accessed B MAR stores the instructions of the program that is running C MDR stores the data passed to it from the PC D ACC stores the result of each calculation E CIR stores the instruction currently being executed Two of the statements are not correct. Identify the letter of each incorrect statement. Suggest a corrected statement for each. Incorrect statement 1......................................... Corrected statement....................................................................................................................................................................................................................................................................................................................................................................................................................... Incorrect statement 2......................................... Corrected statement....................................................................................................................................................................................................................................................................................................................................................................................................................... (b) The computer has a single core 3.5 GHz processor and an 8 kB cache. (i) State what is meant by a 3.5 GHz processor................................................................................................................................................................................................................................................................................. © UCLES 2024 0478/12/F/M/24  5 (ii) The CPU is changed to a dual-core 3.5 GHz processor. Explain how the number of cores affects the performance of a CPU....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (iii) The amount of cache is increased to 64 kB. Explain how the amount of cache affects the performance of a computer....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (c) The computer has both primary and secondary storage. (i) Random access memory (RAM) is one example of primary storage. Describe what is meant by RAM....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (ii) Read only memory (ROM) is another example of primary storage. ROM often stores the start-up instructions for a computer. Identify one other item of data that is commonly stored in ROM................................................................................................................................................................................................................................................................................. (iii) Some computers make use of virtual memory. State the purpose of virtual memory................................................................................................................................................................................................................................................................................. © UCLES 2024 0478/12/F/M/24 [Turn over  6 3 A computer has an operating system (OS). (a) Complete the table by writing each missing OS function name and description. Function name Description …………………………………………………………………………… …………………………………………………………………………… managing memory …………………………………………………………………………… …………………………………………………………………………… ……………………................… allows application software to run on the computer ……………………................… …………………………………………………………………………… …………………………………………………………………………… managing peripherals …………………………………………………………………………… …………………………………………………………………………… (b) The OS handles interrupts. (i) State the purpose of an interrupt................................................................................................................................................................................................................................................................................. (ii) Identify one input device and one example of an interrupt that it can generate. Input device....................................................................................................................... Interrupt............................................................................................................................. © UCLES 2024 0478/12/F/M/24  7 (iii) A processor is currently executing a program. The processor receives an interrupt. Explain how the processor manages the current program and the interrupt.................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... © UCLES 2024 0478/12/F/M/24 [Turn over  8 4 A student enters a uniform resource locator (URL) into their web browser. Draw and annotate a diagram to show the process from the user entering the URL to the web browser displaying the web page. © UCLES 2024 0478/12/F/M/24  9 5 Complete the description of digital currencies using the terms provided. blockchains changed datachains decentralised deleted encryption passport physical address physically records time-stamp traced transaction-chains virtually A digital currency does not exist........................................................... , it can only be accessed electronically. Some digital currencies have digital ledgers called............................................................ These are decentralised databases where each transaction is stored as a new set of data with a........................................................... and is linked to the previous set of data. This means that transactions cannot be altered, only new transactions added, which allows the location of the data to be............................................................ © UCLES 2024 0478/12/F/M/24 [Turn over  10 6 A self-driving tractor sows seeds and harvests crops for a farmer. The self-driving tractor moves automatically through the field, turning at each end and stopping when it has finished. (a) One reason the self-driving tractor is a robot is because it has a mechanical structure that includes wheels, an engine, and a framework. Give one other reason why the self-driving tractor is an example of a robot................................................................................................................................................................................................................................................................................................. (b) If a person is detected within 3 metres whilst the tractor is moving, the self-driving tractor must stop. (i) Explain how an infra-red sensor, microprocessor and actuator can be used to stop the self-driving tractor if a person is detected within 3 metres......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (ii) Identify one other sensor that the self-driving tractor might use and how it will use the sensor. Sensor............................................................................................................................... Use............................................................................................................................................................................................................................................................................... © UCLES 2024 0478/12/F/M/24  11 (c) Explain the drawbacks of a farmer using a self-driving tractor to sow seeds and harvest crops............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. (d) The self-driving tractor has an in-built expert system that the farmer can use to solve any errors with the tractor. Identify three components of an expert system. 1................................................................................................................................................ 2................................................................................................................................................ 3................................................................................................................................................ (e) At the end of each day the self-driving tractor transmits the data it has collected to the farmer’s computer in their house. The transmission uses an echo check. (i) Describe the role of the self-driving tractor and the farmer’s computer in the echo check............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. © UCLES 2024 0478/12/F/M/24 [Turn over  12 (ii) Another method of error checking is a parity block check. The table shows 7 bytes that are transmitted using odd parity. The parity bit has been completed for each byte. Complete the parity byte for the data. parity bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit byte 1 1 1 0 0 1 1 1 0 byte 2 1 0 0 0 0 1 1 0 byte 3 0 1 0 0 0 0 0 0 byte 4 0 1 0 0 1 1 1 1 byte 5 1 0 0 0 0 0 0 0 byte 6 0 1 1 1 1 1 1 1 byte 7 1 1 0 0 1 1 0 1 parity byte © UCLES 2024 0478/12/F/M/24  13 7 Data is transmitted using the internet. (a) The data is encrypted before transmission. (i) State the purpose of encrypting data................................................................................................................................................................................................................................................................................. (ii) Describe the differences between symmetric and asymmetric encryption................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (b) The data is transmitted using packet switching. (i) Identify two items of data contained in a packet header. 1........................................................................................................................................ 2........................................................................................................................................ (ii) Give the purpose of a router in the packet-switching process................................................................................................................................................................................................................................................................................. © UCLES 2024 0478/12/F/M/24 [Turn over  14 8 (a) Hexadecimal can be used to represent binary numbers. (i) Convert the denary number 236 into hexadecimal................................................................................................................................................................................................................................................................................. Working space................................................................................................................................................................................................................................................................................................................................................................................................................................. (ii) Give one benefit of using hexadecimal instead of binary to represent data................................................................................................................................................................................................................................................................................. (b) Two’s complement can be used to represent positive and negative binary integers. (i) Convert the two’s complement integer 10110111 into denary. Show all your working.................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. (ii) Convert the denary number 45 into an 8-bit two’s complement integer................................................................................................................................................................................................................................................................................. Working space................................................................................................................................................................................................................................................................................................................................................................................................................................. © UCLES 2024 0478/12/F/M/24  15 (c) Logical shifts are performed on binary integers. State the mathematical effect of a right shift of four places on a positive binary integer.................................................................................................................................................................................................................................................................................................................................................................................................................................................... © UCLES 2024 0478/12/F/M/24  16 BLANK PAGE 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. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge. © UCLES 2024 0478/12/F/M/24