Cambridge IGCSE Computer Science (9-1) 0984 — 2023 May/June Paper 1 · Variant 2

This document has 12 pages. Any blank pages are indicated. [Turn over Cambridge IGCSE™(9–1) * 9 2 6 1 0 7 7 5 9 1 * DC (KS) 326832 © UCLES 2023 COMPUTER SCIENCE 0984/12 Paper 1 Computer Systems May/June 2023 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.

2 0984/12/M/J/23 © UCLES 2023 1 Output devices are used to output data from a computer. Circle three devices that are output devices. actuator digital versatile disk (DVD) keyboard microphone mouse printer scanner sensor solid‑state drive (SSD) speaker [3] 2 Binary numbers can be converted to hexadecimal. (a) Convert the two binary numbers to hexadecimal. 10010011 … 00001101 … [4] Working space … … … … (b) A value is stored as a binary number in a register. 0 1 1 1 1 0 1 0 A logical right shift of three places is performed on the binary number. (i) Complete the binary register to show its contents after this logical right shift. [1] (ii) State one effect this logical shift has on the binary number. … … [1]

3 0984/12/M/J/23 © UCLES 2023 [Turn over (c) Give two reasons why a programmer may use hexadecimal to represent binary numbers. 1 … … 2 … … [2] (d) Denary numbers can also be converted to hexadecimal. Convert the denary number to hexadecimal. 301 … [2] Working space … … … …

4 0984/12/M/J/23 © UCLES 2023 3 When keys are pressed on a keyboard, the text is converted to binary to be processed by the computer. (a) Describe how the text is converted to binary to be processed by the computer. … … … … … … [3] (b) Text that is input into a computer can be stored in a text file. A text file can be compressed using lossless compression. (i) State what effect this has on the file size. … … [1] (ii) Describe how lossless compression compresses the text file. … … … … … … … … [4] (iii) Give two reasons why the text file may have been compressed. 1 … … 2 … … [2]

5 0984/12/M/J/23 © UCLES 2023 [Turn over 4 A student uses a mobile phone to take photographs for a school project. The student needs to transmit the photographs to their computer. They could use serial data transmission or parallel data transmission to transmit the photographs. (a) (i) Describe how the photographs would be transmitted using serial data transmission. … … … … [2] (ii) Give two benefits of transmitting the photographs using serial data transmission. 1 … … 2 … … [2] (iii) State one benefit of the student using parallel data transmission instead of serial data transmission. … … [1] (b) The photographs are also transmitted across a network to cloud storage. A device on the network forwards the data towards its correct destination. (i) State the name of this device. … [1] (ii) Describe what is meant by cloud storage. … … … … [2] (iii) Give one disadvantage of storing the photographs in cloud storage instead of storing them locally. … … [1]

6 0984/12/M/J/23 © UCLES 2023 5 A programmer writes a computer program using a high‑level language. (a) Tick (3) one box to show which statement is correct about writing computer programs in a high‑level language. A Mnemonics are used to create instructions. B The computer program is harder to debug than a low‑level language program. C The computer program is machine independent. D The hardware of the computer can be directly manipulated. [1] (b) The programmer uses a compiler to translate the computer program. (i) Describe how the compiler translates the computer program. … … … … … … [3] (ii) Describe how the compiler reports errors. … … … … [2] (c) The programmer uses an integrated development environment (IDE) to create the computer program. One function of the IDE is that it has the built‑in compiler. Give three other common functions of an IDE. 1 … 2 … 3 … [3]

7 0984/12/M/J/23 © UCLES 2023 [Turn over 6 (a) Complete the statements about cookies. Use the terms from the list. Some of the terms in the list will not be used. Some terms may be used more than once. compression executable hypertext markup language (HTML) hypertext transfer protocol (HTTP) image internet protocol (IP) address persistent session sound text uniform resource locater (URL) web browser web server Cookies are small … files that are sent between a … and a … . … cookies are stored in memory and not in the user’s secondary storage. When the web browser is closed a … cookie is lost, whereas a … cookie is not lost. [6] (b) Give three functions of a cookie. 1 … 2 … 3 … [3]

8 0984/12/M/J/23 © UCLES 2023 7 A distributed denial of service attack (DDoS) is a cyber security threat. (a) Draw and annotate a diagram to represent the process of a DDoS. [6]

9 0984/12/M/J/23 © UCLES 2023 [Turn over (b) State two aims of carrying out a DDoS attack. 1 … … 2 … … [2] (c) Give two security solutions that can be used to help prevent a DDoS attack being successful. 1 … … 2 … … [2] 8 A computer is connected to a network and assigned an IPv4 address. (a) Tick (3) one box to show which device would assign the IPv4 address to the computer. A Domain name server (DNS) B Network interface card (NIC) C Router D Web server [1] (b) Describe the characteristics of an IPv4 address. … … … … … … … … [4]

10 0984/12/M/J/23 © UCLES 2023 9 One component of an expert system is the inference engine. (a) Identify the three other components in an expert system. 1 … 2 … 3 … [3] (b) Describe the role of the inference engine in an expert system. … … … … [2]

11 0984/12/M/J/23 © UCLES 2023 10 A user has both system software and application software installed on their computer. (a) Describe the difference between system software and application software. Give an example of each software in your answer. … … … … … … … [4] (b) State which component in the computer would store both types of software when the power is turned off. … [1]

12 0984/12/M/J/23 © UCLES 2023 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. BLANK PAGE

This document consists of 10 printed pages. © UCLES 2023 [Turn over Cambridge IGCSE™ (9–1) COMPUTER SCIENCE 0984/12 Paper 1 Computer Systems May/June 2023 MARK SCHEME Maximum Mark: 75 Published 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, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the May/June 2023 series for most Cambridge IGCSE, Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level components.

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2023 © UCLES 2023 Page 2 of 10 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these marking principles. GENERIC MARKING PRINCIPLE 1: Marks must be awarded in line with:  the specific content of the mark scheme or the generic level descriptors for the question  the specific skills defined in the mark scheme or in the generic level descriptors for the question  the standard of response required by a candidate as exemplified by the standardisation scripts. GENERIC MARKING PRINCIPLE 2: Marks awarded are always whole marks (not half marks, or other fractions). GENERIC MARKING PRINCIPLE 3: Marks must be awarded positively:  marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate  marks are awarded when candidates clearly demonstrate what they know and can do  marks are not deducted for errors  marks are not deducted for omissions  answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question as indicated by the mark scheme. The meaning, however, should be unambiguous. GENERIC MARKING PRINCIPLE 4: Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors.

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2023 © UCLES 2023 Page 3 of 10 GENERIC MARKING PRINCIPLE 5: Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be limited according to the quality of the candidate responses seen). GENERIC MARKING PRINCIPLE 6: Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade descriptors in mind. Mark scheme abbreviations / separates alternative words / phrases within a marking point // separates alternative answers within a marking point underline actual word given must be used by candidate (grammatical variants accepted) max indicates the maximum number of marks that can be awarded ( ) the word / phrase in brackets is not required, but sets the context Note: No marks are awarded for using brand names of software packages or hardware.

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2023 © UCLES 2023 Page 4 of 10 Question Answer Marks 1 One mark for each correct device:  Actuator  Printer  Speaker 3 Question Answer Marks 2(a) One mark per each correct character in the correct order:  9  3  0  D 4 2(b)(i)  00001111 1 2(b)(ii) Any one from:  The value becomes incorrect/inaccurate as the right most bits are lost  It is divided by 8 1 2(c) Any two from:  Easier/quicker to understand/read/write  Easier/quicker to debug  Less likely to make a mistake  Shorter representation // Takes up less screen space 2 2(d) One mark for two correct characters, two marks for three correct characters in the correct order:  1  2  D 2

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2023 © UCLES 2023 Page 5 of 10 Question Answer Marks 3(a) Any three from:  A character set is used  … such as Unicode/ASCII  Each character has a unique binary value 3 3(b)(i)  It reduces the file size 1 3(b)(ii) Any four from:  A compression algorithm is used  … such as RLE/run length encoding  Repeating words/characters/phrases are identified // Patterns are identified  … and indexed  … with number of occurrences  … with their position 4 3(b)(iii) Any two from: e.g.  To save storage space  To make it quicker to transmit  To make it small enough to attach to an email  To reduce the bandwidth needed to transmit 2 Question Answer Marks 4(a)(i) Two from:  Data is sent one bit at a time  A single wire is used 2 4(a)(ii) Any two from:  Data won’t be skewed  Less chance of interference/crosstalk/corruption/error  Transmission speed is adequate 2 4(a)(iii)  The data may be transmitted quicker 1

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2023 © UCLES 2023 Page 6 of 10 Question Answer Marks 4(b)(i)  Router 1 4(b)(ii) Any two from:  A collection of servers  … that store data in a remote location // that allows data to be accessed remotely  … that are (normally) accessed using an internet connection 2 4(b)(iii) Any one from: e.g.  May be less secure // by example  May lose access to them if internet connection lost/not available  Reliant on a third party maintaining the hardware // by example  Could incur an extra/ongoing fee/cost 1 Question Answer Marks 5(a)  C 1 5(b)(i) Any three from:  It translates the (high-level language) to low-level language/object code/machine code  It translates all the code before it is executed  It creates an executable file 3 5(b)(ii) Any two from:  It creates an error report after trying to compile  … displaying all errors in the code  … that require correction before execution can take place 2

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2023 © UCLES 2023 Page 7 of 10 Question Answer Marks 5(c) Any three from: e.g.  Code editors  Run-time environment  Built-in interpreter  Error diagnostics  Auto-completion  Auto-correction  Prettyprint 3 Question Answer Marks 6(a) One mark for each correct term.  Text  Web browser // web server  Web server // web browser  Session  Session  Persistent 6 6(b) Any three from: e.g.  Saving personal details  Storing login details  Tracking user preferences  Holding items in an online shopping cart 3

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2023 © UCLES 2023 Page 8 of 10 Question Answer Marks 7(a) One mark for each part of the diagram (MAX six). The diagram demonstrates:  Malware downloaded to several computers  … turning it into a bot/zombie  … creating a network of bots/zombies  Third party/hacker initiating the attack  Bots send requests to a web server at the same time  The web server fails due to the requests  Legitimate requests cannot reach the web server 6 BOT BOT BOT Botnet Malware downloaded to computers turning them into bots Web server Computer Third party Initiates attack Requests web server fails due to too many requests Cannot connect to web server X

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2023 © UCLES 2023 Page 9 of 10 Question Answer Marks 7(b) Any two from: e.g.  Revenge  To affect a company’s reputation  Entertainment value  To demand a ransom to stop it  To test a system’s resilience 2 7(c) Any two from:  Proxy server  Firewall  Users scanning their computers with anti-malware 2 Question Answer Marks 8(a)  C 1 8(b) Four marks from: Any FOUR from:  It is denary based  … with numbers between 0 and 255  It is 32 bits  4 sets/groups of numbers  … separated by dots Any TWO from:  It is a unique address  It can be static or dynamic  It can be public or private  It contains the network prefix  … and the host number 4

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2023 © UCLES 2023 Page 10 of 10 Question Answer Marks 9(a) Three from:  Rule base  Knowledge base  Interface 3 9(b) Any two from:  It makes decisions  … by applying the rules/logic to the facts/knowledge …  … to provide a result/diagnosis 2 Question Answer Marks 10(a) Two from:  System software provides services that the computer requires  … whereas application software provides services that the user requires One from (system software):  Utility software // by example e.g. defragmentation software, antivirus, firewall  Operating system One from (application software):  Any suitable example of an application e.g. word processor, web browser, video-editing software 4 10(b)  Secondary storage // HDD // SSD 1