Cambridge IGCSE Computer Science (9-1) 0984 — 2025 May/June Paper 1 · Variant 2

This document has 12 pages. [Turn over * 6 0 3 7 5 9 0 4 8 5 * Cambridge IGCSE™(9–1) COMPUTER SCIENCE 0984/12 Paper 1 Computer Systems May/June 2025 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. DC (DE) 353935 © UCLES 2025 ,










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2 0984/12/M/J/25 © UCLES 2025 1 A computer stores data temporarily in random access memory (RAM). (a) RAM is one example of primary storage. Give one other example of primary storage. … [1] (b) Give one reason why data is only stored temporarily in the RAM. … … [1] (c) The denary numbers 19 and 230 are converted to binary numbers to be stored in the RAM. Convert the two denary numbers to binary numbers. 19 … 230 … [2] Working space … … … … (d) The hexadecimal numbers 35 and 8AD are converted to binary numbers to be stored in the RAM. Convert the two hexadecimal numbers to binary numbers. 35 … 8AD … [2] Working space … … … … * 0000800000002 * ,










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3 0984/12/M/J/25 © UCLES 2025 [Turn over (e) The 8-bit binary numbers 01100101 and 01110000 are stored in RAM. The binary numbers are added together. Add the two binary numbers using binary addition. Give your answer in binary. You must show all your working. 0 1 1 0 0 1 0 1 + 0 1 1 1 0 0 0 0 [3] (f) An overflow occurs when two other 8-bit binary numbers are added together. Explain why the overflow error occurs. … … … … [2] (g) The negative denary number –22 is stored in RAM. Negative denary numbers can be represented as binary using two’s complement. Give the two’s complement 8-bit binary integer that would be stored for the denary number –22. You must show all your working. Working space … … … … … … Two’s complement 8-bit binary integer … [2] * 0000800000003 * ,










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4 0984/12/M/J/25 © UCLES 2025 2 A student has an image file stored on their computer. (a) The image file was taken by a digital camera. Tick (✓) one box to show whether a digital camera is an example of an input, output, process or storage device. A input B output C process D storage [1] (b) The size of the image file is 3072 bytes. (i) Give the size of the image file in kibibytes (KiB). … [1] (ii) State the number of nibbles in 1 byte. … [1] Working space … … … … (c) The image file has a colour depth of 32 bits. (i) State what is meant by a colour depth of 32 bits. … … [1] (ii) The colour depth of the image file is changed to 64 bits. Explain what effect this change has on the image file. … … … … [2] * 0000800000004 * ,










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5 0984/12/M/J/25 © UCLES 2025 [Turn over (d) The student uses lossless compression to compress the image file. Explain how the image file is compressed using lossless compression. … … … … … … [3] * 0000800000005 * ,










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6 0984/12/M/J/25 © UCLES 2025 3 A programmer writes a program to store and sort all the data for the books in her home library. (a) The programmer uses a high-level language to write the program. One reason for writing the program using a high-level language is that it is easier to read and write. Give two other reasons why the programmer chose to use a high-level language. 1 … … 2 … … [2] (b) The programmer uses an integrated development environment (IDE) to write the program. One function of the IDE is to provide a translator. (i) Complete the statements about translators. Use the terms from the list. Some of the terms will not be used. You should only use a term once. all together all assembler binary error executable file executing interrupt line by line partial code some translating whole code A compiler translates the … at once before … it. A compiler produces an error report that displays … errors. An interpreter translates and executes the code … . An interpreter stops execution when an … is found and continues once it is corrected. [5] * 0000800000006 * ,










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7 0984/12/M/J/25 © UCLES 2025 [Turn over (ii) Give two other functions commonly found in an IDE. State the role of each function. Function 1 … Role … … Function 2 … Role … … [4] (c) The programmer wants to print a list of all her books on paper. (i) Identify a suitable type of printer that she could use to print this list. … [1] (ii) The programmer needs to connect the printer to her computer. The printer is on the same desk as her computer. Give a suitable method of data transmission that could be used to connect the computer to the printer. Explain your choice. Data transmission method … Explanation … … … … … … … … … … … [6] * 0000800000007 * ,










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8 0984/12/M/J/25 © UCLES 2025 (iii) An even parity check is used to detect errors in the data after it has been transmitted to the printer. Describe how an even parity check detects an error. … … … … … … … … … … [4] * 0000800000008 * ,










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9 0984/12/M/J/25 © UCLES 2025 [Turn over 4 An employee uses a computer that has a Von Neumann architecture to complete many different tasks in their working day. (a) The computer has a central processing unit (CPU). Complete the table of components in the CPU and their descriptions. Component Description … It sends signals to all the components in the CPU to manage the flow of data through the CPU. … It carries out all the arithmetic and logic operations in the CPU. cache … … … program counter (PC) … … … … It controls the number of fetch–decode–execute (FDE) cycles that are performed per second. … It stores data immediately before it is transmitted to RAM and immediately after it is received from RAM. [6] (b) The computer is an example of a general purpose computer and not an embedded system. Explain why the computer is not an embedded system. … … … … [2] * 0000800000009 * ,










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10 0984/12/M/J/25 © UCLES 2025 5 A hospital has computers and technology that it uses when caring for its patients. (a) One computer is an expert system that is used to help diagnose a patient’s illness. The doctor inputs the patient’s symptoms into an interface and a diagnosis is output. Describe how the expert system decides the diagnosis. … … … … … … [3] (b) The hospital has a robot that is used to perform surgery. A doctor controls the robot from a different location to perform surgery on a patient. (i) One feature of the robot is that it has electrical components. Give two examples of the electrical components of a robot. 1 … 2 … [2] (ii) Explain the advantages of using the robot to perform surgery. … … … … … … … … [4] * 0000800000010 * ,










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11 0984/12/M/J/25 © UCLES 2025 [Turn over (iii) Explain one disadvantage of using the robot to perform surgery. … … … … [2] (c) Patients use a web page to log into their account to pay for the treatment they have received in the hospital. (i) The patient enters the uniform resource locator (URL) for the web page into their browser and the web page is requested and displayed. Complete and annotate the diagram to show how the web page is requested for the patient. URL input into patient’s computer Patient’s computer www.cihospital.com [6] * 0000800000011 * ,









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12 0984/12/M/J/25 © UCLES 2025 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. (ii) A patient is making a payment through a secure connection. The secure connection is created using the secure socket layer (SSL) protocol. Explain how a secure connection is created using the SSL protocol. … … … … … … … … … … … … [6] * 0000800000012 * ,









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This document consists of 15 printed pages. © Cambridge University Press & Assessment 2025 [Turn over Cambridge IGCSE™ (9–1) COMPUTER SCIENCE 0984/12 Paper 1 Theory May/June 2025 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 2025 series for most Cambridge IGCSE, Cambridge International A and AS Level components, and some Cambridge O Level components.

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 2 of 15 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alon gside the specific content of the mark scheme or generic level descriptions 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 2025 © Cambridge University Press & Assessment 2025 Page 3 of 15 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 thre sholds or grade descriptors in mind.

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 4 of 15 Annotations guidance for centres Examiners use a system of annotations as a shorthand for communicating their marking decisions to one another. Examiners are trained during the standardisation process on how and when to use annotations. The purpose of annotations is to inform the standard isation and monitoring processes and guide the supervising examiners when they are checking the work of examiners within their team. The meaning of annotations and how they are used is specific to each component and is understood by all examiners who mark the component. We publish annotations in our mark schemes to help centres understand the annotations they may see on copies of scripts. Note that there may not be a direct correlation between the number of annotations on a script and the mark awarded. Similarly, the use of an annotation may not be an indication of the quality of the response. The annotations listed below were available to examiners marking this component in this series. Annotations Annotation Meaning Correct point Incorrect point Unclear response Follow through Repetition Ignore Benefit of doubt given Benefit of doubt not given Content of response too vague Not answered question

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 5 of 15 Annotation Meaning Omission Section not relevant Section incorrect Highlighter Information copied from the text Page or response seen by examiner Annotation guidance: / separates alternative words or 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 2025 © Cambridge University Press & Assessment 2025 Page 6 of 15 Question Answer Marks 1(a) Any one from: • ROM • Cache 1 1(b) Any one from: • It is volatile storage // Data is lost when the power is turned off. • It needs to be regularly replaced by other data // The data regularly changes // Data needs to be constantly updated 1 1(c) • 10011 • 11100110 2 1(d) • 0011 0101 • 1000 1010 1101 2 1(e) One mark for each correct nibble (MAX 2) One mark for a correct method of working e.g. showing carries. 1 1 0 1 1 0 0 1 0 1 + 0 1 1 1 0 0 0 0 1 1 0 1 0 1 0 1 3 1(f) Any two from: • The result is greater than 255 // The result is too large. • Cannot be stored in 8 bits // Cannot be stored in the number of bits available for the register 2 1(g) One mark for a correct working method e.g. flip and add One mark for correct answer 11101010 2

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 7 of 15 Question Answer Marks 2(a) A 1 2(b)(i) 3 1 2(b)(ii) 2 1 2(c)(i) 32 bits are used to represent each/a/one colour in the image // 232 (approx. 4.3 billion) different colours can be used/are available for the image 1 2(c)(ii) Any two from: • The size of the image file increases. • … as the number of bits used to represent/store a colour has increased 2 2(d) Any three from: • The size of the file is reduced without permanently removing any data. • A compression algorithm is used. • … such as Run length encoding/RLE. • Repeating pixels are grouped/identified … // Patterns are identified … • … and stored with the number of times they are repeated. • … and indexed 3

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 8 of 15 Question Answer Marks 3(a) Any two from: • It is easier to debug. • Less likely to make errors. • The program is machine independent/portable 2 3(b)(i) One mark for each correct term in the correct place. • whole code • executing • all • line by line • error A compiler translates the whole code at once before executing it. A compiler produces an error report that displays all errors. An interpreter translates and executes the code line by line. An interpreter stops execution when an error is found and continues once it is corrected. 5

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 9 of 15 Question Answer Marks 3(b)(ii) One mark for each correct function. One mark for each correct matching role description. Examples: • Code editor • Allows the programmer to write/change the program. • Run-time environment • Allows the user to run the code and see the output. • Error diagnostics • Features that can be used to find errors in the code • Auto-completion • A programmer starts to type a command word, and the IDE suggests option for completing it. • Auto-correction • If a programmer misspells a command word it is changed to the correct spelling • Prettyprint • The command words/identifiers are given different colours 4 3(c)(i) Any one from: • Inkjet • Laser 1

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 10 of 15 Question Answer Marks 3(c)(ii) One mark from: • Serial • Parallel One mark from: • Half-duplex • Full-duplex • Simplex Any four from (for descriptions matching transmission types given): serial • Serial would send bits in order // serial uses only one wire. • … so won’t be skewed // less likely to have errors • Serial transmission speed would be adequate. parallel • Parallel would transmit data faster. • … as multiple bits are sent at the same time // … as multiple wires are used. • For parallel, chance of skewing/errors would be low as short distance transmission only required. half/full duplex • To allow data to be sent in both directions • … so any interrupts/notifications for errors can be sent back to the computer. simplex • Data only needs to be sent one direction // Data transmission doesn’t need to be two-way. • … as the printer may not need to send errors back to the computer 6

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 11 of 15 Question Answer Marks 3(c)(iii) • A parity bit is added to each byte. • … to make the number of 1s/0s even // that will be 1 if the number of 1s/0s is odd // that will be 0 if the number of 1s/0s is even. • The number of 1s/0s in each byte is counted after transmission. • If any bytes have an odd number of 1s/0s an error is detected 4 Question Answer Marks 4(a) One mark for each correct component or description Component Description Control unit // CU It sends signals to all the components in the CPU to manage the flow of data through the CPU. Arithmetic and logic unit // ALU It carries out all the arithmetic and logic operations in the CPU. Cache It stores frequently used data/instructions Program counter (PC) It stores the address of the next instruction to be fetched Clock It controls the number of fetch-decode-execute (FDE) cycles that are performed per second. Memory data register // MDR It stores data immediately before it is transmitted to RAM and immediately after it is received from RAM. 6

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 12 of 15 Question Answer Marks 4(b) Two from: • An embedded system is designed to perform a dedicated/limited/single function // computer can be used to perform many different functions. • An embedded system has dedicated hardware // computer has hardware that can be used by other devices. • An embedded system has software that is not easily updated/reprogrammed // software can easily be updated/reprogrammed on the computer. • An embedded system has a microprocessor // A computer has a CPU. • An embedded system can be part of/built into a larger device // A computer is normally standalone 2 Question Answer Marks 5(a) Three from: • The inference engine is used … • … to decide which questions to ask the user … • … based on the previous data input. • Symptoms input are located in/compared to knowledge base. • … then applies the rule base to the knowledge base (to decide the diagnosis) 3 5(b)(i) Any two from: Examples: • Sensors • Microprocessors • Actuators 2

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 13 of 15 Question Answer Marks 5(b)(ii) Any four from: Examples: • a doctor doesn’t need to travel to the hospital to do the surgery. • … so it can be done by any specialist/doctor in the world. • … so it can be done immediately without needing to wait for travel time // reduces the waiting time for the patient. • … so the doctor may be better at the surgery as they won’t be tired from travel. • … so travel costs are saved. • Surgery with robots enhances precision/accuracy. • … so a smaller incision can be made. • … so the recovery time may be shorter. • … as the components used to enter the body can be much smaller than a human hand. • … so the surgery is safer/ more hygienic // by example e.g. can stop the doctor needing to be near an infectious patient. • The surgery may have a higher rate of success 4 5(b)(iii) Two from (one for a point and one for the matching expansion): Examples: • The internet connection could be lost/delayed … • … so the surgery may not be able to continue. • The robot will be expensive to buy/maintain … • … this money could have been spent on other causes. • The robot could be hacked …. • … and endanger the patient’s life. • Data could be corrupted in transmission … • … changing the nature of the instruction for the robot. • The robot’s hardware could malfunction … • … so the surgery cannot continue 2

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 14 of 15 Question Answer Marks 5(c)(i) One mark for each correct part of the diagram. The diagram: • Web browser identified as software used to send URL/requests or receives IP address/web page data • URL/domain sent to DNS • DNS searches for matching IP address • If not found sent to another DNS • IP address sent from DNS to patient’s computer • Request sent from patient’s computer to web server (for web page) • Web page/HTML data sent from web server to patient’s computer 6 Patient’s computer www.cihospital.com URL input into patient’s computer DNS 1 Web server DNS 2 URL IP address searches for matching IP If URL not found, sent to another DNS Request Web page data

0984/12 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 15 of 15 Question Answer Marks 5(c)(ii) Any six from: • Encrypted connection established … • … using asymmetric encryption • … to make any data sent meaningless • The web browser asks the web server to identify itself. • … by sending its digital certificate. • The digital certificate is authenticated/validated by the web browser. • If the certificate is authenticated/valid, the connection is secure/the transaction can begin. • If the certificate is not authenticated/invalid, the connection is not secure/the transaction is cancelled/rejected/user is notified 6