Cambridge A Level Computer Science 9618 — 2025 Oct/Nov Paper 1 · Variant 2

This document has 16 pages. [Turn over Cambridge International AS & A Level * 0 8 0 0 4 2 1 0 5 5 * COMPUTER SCIENCE 9618/12 Paper 1 Theory Fundamentals October/November 2025 1 hour 30 minutes You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. ● 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. ● You may use an HB pencil for any diagrams, graphs or rough working. ● 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 (PB/FC) 346716/3 © UCLES 2025 ,










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2 9618/12/O/N/25 © UCLES 2025 1 Draw one line from each verification method to indicate whether it is used during data transfer or data entry. Verification Method Parity byte check Checksum Visual check Parity block check Use Data transfer Data entry [2] 2 (a) Complete the table by describing each term. Term Description Copyright … … … Open Source (Initiative) … … … Shareware … … … Software Licence … … … [4] * 0000800000002 * ,










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3 9618/12/O/N/25 © UCLES 2025 [Turn over (b) Describe the purpose of a code of conduct. … … … … [2] 3 (a) (i) State what is meant by relative addressing. … … … [1] (ii) Registers such as the Accumulator (ACC) and the Index Register (IX) are used in the CPU. Identify two special purpose registers used in the CPU. Do not include the ACC or IX in your answers. 1 … 2 … [2] * 0000800000003 * ,










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4 9618/12/O/N/25 © UCLES 2025 (b) The following table shows part of the instruction set for a processor. The processor has two registers: the ACC and an IX. Instruction Explanation Opcode Operand LDM #n Immediate addressing. Load the number n to ACC LDD <address> Direct addressing. Load the contents of the location at the given address to ACC LDI <address> Indirect addressing. The address to be used is at the given address. Load the contents of this second address to ACC LDX <address> Indexed addressing. Form the address from <address> + the contents of the index register. Copy the contents of this calculated address to ACC LDR #n Immediate addressing. Load the number n to IX <address> can be an absolute or symbolic address # denotes a denary number, e.g. #127 The current contents of the main memory and the index register are shown. Address Instruction 98 8 99 16 100 3 101 98 102 32 IX 2 Write the contents of the ACC after each instruction is executed. Instruction Value in ACC LDM #98 LDI 101 LDX 100 [3] * 0000800000004 * ,










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5 9618/12/O/N/25 © UCLES 2025 [Turn over (c) A student buys a new computer. The table shows the specifications of the old computer and the new computer. Old computer New computer 1.8 GHz dual core processor 2.3 GHz dual core processor 16 MB cache 32 MB cache Explain why increasing the clock speed and increasing the cache memory will improve the performance of the computer. Clock speed … … … … Cache memory … … … … [4] * 0000800000005 * ,










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6 9618/12/O/N/25 © UCLES 2025 4 A relational database, SHIPPING, stores data about the ships in a company and the containers that are carried on the ships. The database has the following tables: CONTAINER(ContainerID, Type, Weight, OwnerName, ShipID) SHIP(ShipID, Type, Capacity, ShipName) (a) Describe the relationship between the two tables. Refer to the primary and foreign keys in your answer. … … … … [2] (b) The table CONTAINER needs an additional field to store the data for the last inspection date. Write a Structured Query Language (SQL) script to add one field to the table CONTAINER to store the date of last inspection of the container, for example 08/07/2019. … … … … [2] (c) Write an SQL script to return the number of containers stored in the database for the ship with the name Caledonia. … … … … … … [4] * 0000800000006 * ,










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7 9618/12/O/N/25 © UCLES 2025 [Turn over (d) Describe the purpose of a developer interface in a Database Management System (DBMS). … … … … [2] * 0000800000007 * ,










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8 9618/12/O/N/25 © UCLES 2025 5 A local area network (LAN) has five computers, one switch and one server. (a) Describe the characteristics of a LAN. … … … … [2] (b) Complete the following diagram to show how these devices are connected in a star topology. Computer Computer Computer Server Switch Computer Computer [2] (c) Describe how packets are transmitted between two hosts using a star topology. … … … … … … [3] * 0000800000008 * ,










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9 9618/12/O/N/25 © UCLES 2025 [Turn over (d) Another type of network is a bus network. Ethernet is used to transmit and receive data between the devices on the bus network. Describe how collisions are detected and managed on this network. … … … … … … [3] (e) Complete the table by identifying one threat to computer and data security posed by networks and the internet. Describe the threat and give a method of prevention. Threat Description Prevention … … … … … … … … … … [3] * 0000800000009 * ,










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10 9618/12/O/N/25 © UCLES 2025 6 (a) A sound file is compressed by reducing the sampling rate. State whether this is lossless or lossy compression. Justify your choice. Type of compression … Justification … … … … [1] (b) The following table shows some words and corresponding denary values. Word Denary value Computing 55 Science 56 Computers 57 are 58 Brilliant! 59 is 60 Fun! 61 Amazing! 62 The following table shows three bytes of data that have been received. Use the table to find the corresponding words from the binary values received. Binary value 00111000 00111100 00111110 Word Working … … … … [1] * 0000800000010 * ,










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11 9618/12/O/N/25 © UCLES 2025 [Turn over (c) A computer system uses even parity. The least significant (rightmost) bit of each byte is the parity bit. (i) Complete the byte by writing the missing parity bit: parity bit 0 1 0 1 1 1 0 [1] (ii) The computer also uses parity block check. The parity block check uses even parity. Computer A transmits four bytes of data to computer B, followed by a parity byte. Computer B receives the following sequence of bytes. parity bit 1 0 1 1 0 1 1 1 0 1 1 1 0 0 0 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1 0 0 parity byte 1 0 1 0 0 0 0 0 Following transmission, one of the four bytes of data has an error in one of the bits. Circle the bit that has been altered during the data transfer. [1] (d) A bitmap image has a resolution of 1000 pixels wide by 2000 pixels high. The colour depth is 16 bits. Calculate an estimate of the file size in megabytes. Show your working. … … … … … … File size … megabytes [2] * 0000800000011 * ,









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12 9618/12/O/N/25 © UCLES 2025 7 (a) The following binary addition is performed using 8‑bit registers. Complete the calculation using binary addition. 1 0 0 0 0 1 1 1 + 0 0 1 1 1 0 0 1 [1] (b) A computer uses the Unicode character set. State the number of bits used to store one character from the Unicode character set. … [1] (c) ASCII is another character set. The ASCII value for the character ‘h’ has the denary value 104. (i) Write the Binary Coded Decimal (BCD) value for the ASCII character ‘h’. … [1] (ii) Write the hexadecimal value for the ASCII character ‘h’. … [1] * 0000800000012 * ,









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13 9618/12/O/N/25 © UCLES 2025 [Turn over 8 A restaurant accesses software and stores data using cloud computing. (a) (i) Give two benefits of storing data using cloud computing. 1 … … 2 … … [2] (ii) Give two drawbacks of using cloud computing. 1 … … 2 … … [2] (b) The restaurant uses touchscreens as input devices to allow staff to select items from a menu. (i) Explain how a touchscreen converts the point of touch to a selection from the menu. … … … … … … … … [4] (ii) The image files that are displayed on the touchscreen have been corrupted. Identify two examples of utility software that could be used to recover the images. 1 … 2 … [2] * 0000800000013 * ,









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14 9618/12/O/N/25 © UCLES 2025 9 (a) Consider the following logic circuit: A B C X Write the logic expression for the logic circuit. Do not simplify the expression. X = … [2] (b) Consider the following logic expression: X = NOT ((A NAND B) XOR (NOT A OR NOT C)) A truth table for the logic expression is given: Row number A B C X 1 0 0 0 1 2 0 0 1 0 3 0 1 0 1 4 0 1 1 0 5 1 0 0 1 6 1 0 1 0 7 1 1 0 1 8 1 1 1 1 There are three errors in the truth table. Identify the three errors in the truth table by writing the row numbers with an incorrect output. Error 1 Row number … Error 2 Row number … Error 3 Row number … [2] * 0000800000014 * ,









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15 9618/12/O/N/25 © UCLES 2025 [Turn over 10 A programmer is developing a computer program. (a) Explain how the programmer can first use an interpreter and then a compiler to develop the computer program. Interpreter … … … … Compiler … … … … [4] (b) The programmer releases the program as Free Software. Describe what is meant by Free Software. … … … … [2] (c) A user downloads the computer program from the internet. State what should be included as part of the download to make sure the program is authentic. … [1] * 0000800000015 * ,









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16 9618/12/O/N/25 © UCLES 2025 11 An automated system opens doors when a person is detected within 2 metres. The system closes the doors when there is no longer a person within 2 metres. Identify whether the automated system is an example of a monitoring system or a control system. Justify your choice. Monitoring or Control … Justification … … … … … … [3] 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. * 0000800000016 * ,









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This document consists of 11 printed pages. © Cambridge University Press & Assessment 2025 [Turn over Cambridge International AS & A Level COMPUTER SCIENCE 9618/12 Paper 1 Theory Fundamentals October/November 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 October/November 2025 series for most Cambridge IGCSE, Cambridge International A and AS Level components, and some Cambridge O Level components.

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 2 of 11 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 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. 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.

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 3 of 11 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 standardisation 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 Incorrect To indicate where a key word/phrase/code is missing. Not relevant or used to separate parts of an answer. Indicates a part of the answer that is incorrect. Highlighter To draw attention to a particular aspect or to indicate where parts of an answer have been combined. Too vague. Repetition No examples or not enough. Benefit of Doubt. Not Answered Question. Indicates that work or a page has been seen including blank answer spaces and blank pages. Follow through. Ignore

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 4 of 11 Question Answer Marks 1 1 mark for 2 or 3 correctly connected verification method boxes, 2 marks for all 4 correct 2 Question Answer Marks 2(a) 1 mark for each correct row, max 4 marks Term Description Copyright Gives the holder the legal right of ownership of intellectual property Open Source (Initiative) Software can be freely copied, distributed or adapted Shareware Gives the user a trial period / limited functionality before a payment/sign up may be required Software Licence A (legal) agreement that defines the rights and terms of usage for the software 4 Parity byte check Checksum Parity block check Data transfer Visual check Data entry Use Verification Method

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 5 of 11 Question Answer Marks 2(b) 1 mark per bullet point, max 2 marks e.g. • to create a safe, respectable and professional working environment for all employees • to ensure that employees understand the expectations • ... and the consequences of their actions • to provide a clear outline of what is considered good practice • so there are clear rules to follow in certain situations • to protect the reputation of the organisation // maintain public trust 2 Question Answer Marks 3(a)(i) 1 mark • The value of the operand is an offset value which is added to another base value to give the address from which the contents are loaded to the accumulator 1 3(a)(ii) 1 mark per bullet point, max 2 marks • Program counter (PC) • Memory Data Register (MDR) • Memory Address Register (MAR) • Current Instruction Register (CIR) • Status Register 2 3(b) 1 mark for each correct value, max 3 marks Instruction Value in ACC LDM #98 98 LDI 101 8 LDX 100 32 3 3(c) 1 mark per bullet point, max 2 marks for each Clock Speed: • Processor can perform more F-E cycles per second • ... so more instructions / data can be processed each second Cache Memory: • Can store more of the most frequently used instructions • … which reduces the need to access slower RAM 4

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 6 of 11 Question Answer Marks 4(a) 1 mark per bullet point, max 2 marks • The relationship between SHIP and CONTAINER is one-to-many (1:M) • The primary key ShipID in the SHIP table is linked to the foreign key ShipID in the CONTAINER table 2 4(b) 1 mark per bullet point, max 2 marks • ALTER TABLE statement • Including the additional field with a suitable field name and suitable field type Example answer ALTER TABLE CONTAINER ADD InspectionDate DATE; 2 4(c) 1 mark per bullet point, max 4 marks • SELECT COUNT statement • Using the correct tables • Joining the tables • The condition for the name Example Answer 1: SELECT COUNT(ContainerID) FROM CONTAINER, SHIP WHERE CONTAINER.ShipID = SHIP.ShipID AND ShipName = "Caledonia"; Example Answer 2: SELECT COUNT(ContainerID) FROM CONTAINER INNER JOIN SHIP ON CONTAINER.ShipID = SHIP.ShipID WHERE ShipName = "Caledonia"; 4 4(d) 1 mark per bullet point, max 2 marks • To allow the user to create / modify / delete tables // maintain the database • To allow the user to set up / modify relationships • To allow the user to create a form for data input • To allow a user to add tools to a form // for example, drop-down boxes / buttons etc. • To allow a user to design a report (to show the output in an organised manner) • To allow a user to add a menu to enable a choice of different actions • To allow a user to inspect the database contents and metadata • ... by creating and/or running different SQL queries 2

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 7 of 11 Question Answer Marks 5(a) 1 mark per bullet point, max 2 marks • Covers a small geographical area • Normally privately owned / dedicated infrastructure • Can use wired or wireless communication 2 5(b) 1 mark per bullet point, max 2 marks • All computers directly connected to switch and no other connections • Switch connected directly to server 2 5(c) 1 mark per bullet point, max 3 marks • The sending device sends the packets to the switch • The switch checks the destination address on each packet • … and sends them only to the intended receiver 3 5(d) 1 mark per bullet point, max 3 marks • The use of CSMA/CD // Carrier Sense Multiple Access with Collision Detection • The workstations listen to the communication channel • ... and send data only when there is no data being transmitted / the line is idle • If a collision is detected, transmission is aborted • …and a jamming signal is sent • The workstation calculates a random wait time before trying to re-transmit • The random time is increased if there are multiple collisions 3

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 8 of 11 Question Answer Marks 5(e) 1 mark for correct threat 1 mark corresponding description 1 mark for correct method of prevention Threat Description Prevention Malware / Virus Malicious code that can alter/delete files Anti-virus // Anti- malware // Firewall Spyware Records keystrokes which are sent to third party Anti-spyware // Firewall // Anti- malware Hacking Gaining unauthorised access to a computer network / device Authentication // Firewall Phishing Emails supposedly from reputable companies are sent to trick people into revealing personal information Use a spam filter // Do not open emails from unknown sources Pharming Users are directed to a bogus website that looks legitimate to obtain personal information Use a VPN // Anti- malware// Do not open links or download attachments 3 Question Answer Marks 6(a) 1 mark for correct answer Type of compression: lossy Justification: There will be fewer samples per second, so data will be permanently lost // There will be fewer samples per second, so the original sound cannot be re- created 1 6(b) 1 mark for correct words in the correct order Binary Value 0011 1000 0011 1100 0011 1110 Word Science is Amazing! 1

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 9 of 11 Question Answer Marks 6(c)(i) 1 mark for correct answer parity bit ↓ 0 1 0 1 1 1 0 0 1 6(c)(ii) 1 mark for correct answer parity bit ↓ 1 0 1 1 0 1 1 1 0 1 1 1 0 0 0 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1 0 0 parity byte→ 1 0 1 0 0 0 0 0 [1] 1 6(d) 1 mark for the working 1 mark for the correct answer Working: (1000 * 2000 * 16) / (8 * 1000 * 1000) // (1000 * 2000 * 2 / (1000 * 1000) Answer: 4 megabytes 2 Question Answer Marks 7(a) 1 mark for the correct answer 1100 0000 1 7(b) 1 mark for the correct answer 8 // 16 // 32 // 64 1 7(c)(i) 1 mark for the correct answer 0001 0000 0100 1 7(c)(ii) 1 mark for the correct answer 68 1

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 10 of 11 Question Answer Marks 8(a)(i) 1 mark per bullet point, max 2 marks • Cloud storage can be free of charge for a limited amount • There is no need for personal storage devices • The data can be accessed from any computer with an internet connection • Cloud data services usually include data backup and recovery services • It is easier to share data / collaborate with colleagues • Cloud storage capacity can be quickly and easily increased if needed 2 8(a)(ii) 1 mark per bullet point, max 2 marks • The storage/cloud can only be accessed with an internet connection • There may be no backups // possibly no control over backups // reliance on third party for backups • Uploading / downloading data could take a long time • Potential issues with the cloud storage company impacting access e.g. downtime or technical problems • Potential compatibility issues if wanting to move the data • Limited storage availability without paying extra • … meaning (possibly) more expensive in the long term • Possibly security issues 2 8(b)(i) 1 mark per bullet point, max 4 marks Methods to determine point of touch (Max 2) • Resistive // two layers of material make contact and complete a circuit • Capacitive // contact with the screen creates a change in charge • Infrared // the beams are broken by the pointing device • Optical imaging // a shadow is created when the surface is touched • Acoustic pulse // the acoustic wave is absorbed by the pointing device • Selection from the menu (Max 2) • The point of touch is used to determine the x and y coordinates • The menu item corresponding to the coordinate position is recognised and the menu item is added to the order 4 8(b)(ii) 1 mark per bullet point, max 2 marks • Disk repair / disk contents analysis • Back-up software 2 Question Answer Marks 9(a) 1 mark per bullet point, max 2 marks • NOT (A XOR B) • NAND ((B AND C) OR A) X = (NOT (A XOR B)) NAND ((B AND C) OR A) // X = ((B AND C) OR A) NAND (NOT (A XOR B)) 2

9618/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 11 of 11 Question Answer Marks 9(b) 1 mark for 1 or 2 row numbers correct, 2 marks all three correct Row 2 Row 4 Row 7 2 Question Answer Marks 10(a) 1 mark per bullet point, max 4 marks Max 2 from each section. Interpreter: • Use an interpreter while writing/coding the program • … to test / debug the partially completed program • … because errors can be corrected and processing continue from where the execution stopped // errors can be corrected in real time // errors are identified one at a time Compiler: • Use the compiler after the program is complete • … to create an executable file so source code not seen • Use the compiler to repeatedly test the same completed section without having to re-interpret every time 4 10(b) 1 mark per bullet point, max 2 • The software is free of restrictions • The software is not necessarily free of charge • The source code comes with the program // A user can edit the source code to add functionality / suit their needs • Users can share the software with others 2 10(c) 1 mark for a correct answer • Digital Signature 1 Question Answer Marks 11 1 mark per bullet point, max 3 marks Identification: Control system (no mark) Justification: • The system uses an actuator to open or close the doors • The output / opening the doors allows people to move, which changes the input to the sensor • The system acts autonomously on the feedback from a sensor 3