GCSE

Computer Science

Unofficial Practice Paper: J277/01: Computer Systems

General Certificate of Secondary Education

Mark Scheme for June 2026 [VERSION B]

This is an unofficial practice resource created exclusively for gcsecomputerscience.co.uk. It is not endorsed by, affiliated with, or approved by Oxford Cambridge and RSA Examinations (OCR).

gcsecomputerscience.co.uk June 2026 Practice Paper (Section A)

Question	Answer / Indicative Content	Mark	Guidance
1 (a)	1 mark per point (max 2): It is faster to access than RAM [1] It stores frequently used instructions or data [1] It is located closer to the CPU [1]	2
1 (b)	1 mark per point (max 2): Multiple cores allow for parallel processing [1] Enables multiple instructions to be executed at the same time [1]	2
1 (c)	1 mark per point (max 2): It determines the number of fetch-execute cycles per second [1] A higher clock speed means more instructions executed per second [1]	2
2 (a)	1 mark per point: Holds the address of the next instruction to be fetched [1] Increments after the fetch stage [1]	2
2 (b)	1 mark per point: Holds the results [1] of calculations performed by the ALU [1]	2
3 (a)	Date created, author, file format, resolution, colour depth, GPS location.	2	1 mark per example (max 2).
3 (b)	1000 × 500 = 500,000 pixels [1] 500,000 × 8 bits = 4,000,000 bits [1] 4,000,000 / 8 = 500,000 bytes [1] 500,000 / 1000 = 500 KB [1]	4	Accept 1024 for division (approx 488 KB). Full marks for correct final answer with units.

gcsecomputerscience.co.uk June 2026 Practice Paper (Section A Continued)

Question	Answer / Indicative Content	Mark	Guidance
4 (a)	1 mark per justification (max 4): Magnetic storage has a higher capacity [1] which is needed for many records [1] It is cheaper per gigabyte than solid state [1], making it cost-effective for large archives [1]	4	Must justify in the context of archiving records.
4 (b)	Durability [1], Reliability [1], Portability [1], Speed [1].	2	Max 2 marks. Do not accept capacity or cost.
5 (a)	To reduce the file size [1] so it takes up less storage space on the disk [1].	2	Accept: Takes less time to transmit.
5 (b)	Lossy permanently removes some data to reduce file size [1], which degrades quality [1]. Lossless compresses without losing any data [1], so the original file can be perfectly restored [1].	4	Must refer to both methods.
6 (a)	AF. (1 mark for A, 1 mark for F).	2
6 (b)	00111110. (1 mark for 0011, 1 mark for 1110).	2
6 (c)	Result: 10001000 [2 marks]. Correct working showing carried bits [2 marks].	4
6 (d)	When the result of a binary addition requires more bits than are available (e.g. 9 bits needed for an 8-bit register) [2]. This can cause data loss or inaccurate calculations [2].	4

gcsecomputerscience.co.uk June 2026 Practice Paper (Section B)

Question	Answer / Indicative Content	Mark
7 (a)	1 mark per point (max 4, 2 per benefit): If one cable fails, the rest of the network is unaffected [2] It is easy to add new devices to the network without disrupting others [2] Fewer data collisions compared to a bus topology [2]	4
7 (b)	1 mark per point (max 4, 2 per benefit): Hospital data can be accessed from any location/device [2] Cloud providers handle backups and security [2] It is easy to scale up storage capacity if the hospital grows [2]	4
8 (a)	An attacker sends a fraudulent email [1] disguised as a legitimate source [1] to trick the user into revealing sensitive information/passwords [1].	3
8 (b)	Malicious SQL code is entered into an input form [1]. It manipulates the database query [1] allowing the attacker to bypass authentication or view/modify patient data [1].	3
9 (a)	It monitors incoming and outgoing network traffic [1]. It uses a set of rules [1] to block or allow packets, preventing unauthorised access [1].	3
9 (b)	Scans files and the system for malicious software [1]. It compares files against a database of known virus signatures [1]. It quarantines or deletes identified malware [1].	3

gcsecomputerscience.co.uk June 2026 Practice Paper (Section B Continued)

Question

Answer / Indicative Content

Mark

Guidance

10 (a)

Open source provides the source code [1] allowing users to modify/distribute it [1]. Proprietary does not provide source code [1] and requires a paid licence to use [1].

4

Must refer to both types.

10 (b)

Unauthorised access to computer material [1]. Unauthorised modification of computer material [1].

2

Accept: Unauthorised access with intent to commit a further offence.

11 (a)

Layers divide the complex task of networking into smaller, manageable parts [1]. Each layer has a specific function [1] and provides services to the layer above it [1]. Developers can change one layer without affecting others [1].

4

11 (b)

Used to identify the physical hardware (NIC) of a device [1] on a local area network [1].

2

12*

Mark Band 3 (6-8 marks): Thorough knowledge. Balances AI benefits against ethical/privacy concerns. Refers to stakeholders clearly. Clear DPA 2018 references. Clear logical structure.

Level	Description
3	Balanced discussion. Detailed stakeholder analysis. Clear DPA 2018 links.
2	Reasonable knowledge. Clear application. One-sided discussion.
1	Basic list. Unsupported assertions. Weak context link.

Indicative Content:

Ethical: AI could be more accurate, saving lives. Responsibility for mistakes (liability). Bias in training data.
Legal (DPA 2018): Patient data must be kept secure. Data processing must have a lawful basis. Consent required for processing medical records by AI.
Stakeholders: Patients (better care but privacy fears), Doctors (tool to assist, but fear of job loss/liability), Hospital Management (cost savings, efficiency).

8

AO2 (4) / AO3 (4)

TOTAL MARKS: 80