GCSE

Computer Science

Unofficial Practice Paper: J277/01: Computer Systems

General Certificate of Secondary Education

Mark Scheme for June 2026 [VERSION D]

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 Version D Mark Scheme (Section A)

Question	Answer / Indicative Content	Mark	Guidance
1 (a)	1 mark per point (max 2): To hold instructions/data that are currently in use [1] To allow the CPU to access data much faster than from secondary storage [1]	2	Must focus on "currently in use" or "CPU access speed".
1 (b)	1 mark per point: ALU: Performs arithmetic calculations (e.g. addition, subtraction) [1] and logical comparisons (e.g. AND, OR, NOT) [1]. CU: Coordinates the activities of the CPU / Decodes instructions [1] and manages the flow of data using control signals [1].	4	Award 2 marks for each component.
1 (c)	Cache size: Provides more space for frequently used instructions [1]. Reducing the time spent fetching data from RAM [1]. Clock speed: Increases the number of fetch-execute cycles per second [1]. Allowing more instructions to be processed in a given time [1].	4	Must link to "workstation performance".
2 (a)	2ⁿ [1] // 2 to the power of n [1].	2	Any notation representing 2^n.
2 (b)	1 mark per point: Resolution increases the number of pixels in the image [1]. Colour depth increases the number of bits stored per pixel [1]. Increasing either factor (or both) leads to a larger file size [1]. The formula is File Size = Width x Height x Colour Depth [1].	4	Any four valid points.
2 (c)	1 mark per point: Analogue wave is measured at regular time intervals [1]. The amplitude/height of the wave at each point is converted to a binary value [1]. Higher sample rate/bit depth results in a more accurate digital representation [1]. The measurements are stored as a sequence of binary numbers [1].	4	Focus on "measurement" and "binary conversion".

gcsecomputerscience.co.uk Version D Mark Scheme (Section A Continued)

Question	Answer / Indicative Content	Mark	Guidance
3 (a)	1 mark per point (max 2): DNS translates/converts the URL into an IP address [1] Allows the browser to locate the correct web server on the internet [1]	2	Must mention "translation" or "conversion" to IP.
3 (b)	1 mark per justification (max 4): Cheaper as no dedicated server hardware is needed [1] Easier to set up/maintain without technical staff [1] No single point of failure (unlike a server) [1] Effective for a low number of users (only 3 computers) [1]	4	Link to "home office" or "3 computers".
3 (c)	NIC: Provides a physical connection to a network [1]. Converts data into a format that can be transmitted over the medium [1]. WAP: Allows wireless devices to connect to a wired network [1]. Transmits and receives data using radio waves [1].	4	Award 2 marks for each component.
4 (a)	Phishing: Sending fraudulent emails pretending to be a reputable source [1] to trick users into revealing sensitive data [1]. Brute-force: An automated attack [1] that systematically tries every possible password combination until the correct one is found [1].	4	Must distinguish between email-based vs. password-guessing.
4 (b)	1 mark per point (max 4): Security professionals / ethical hackers are authorised to simulate an attack [1] They attempt to bypass security / exploit weaknesses in the network [1] To identify / find vulnerabilities before a real hacker does [1] To produce a report / provide recommendations on how to fix the gaps [1]	4	Must focus on "simulated attack" and "identifying vulnerabilities".
4 (c)	Error: Using weak/predictable passwords // Falling for a phishing email [1]. Prevention: Enforcing strong password policies / Using 2-factor authentication // Installing a firewall [1].	2	Prevention must reasonably mitigate the specific error.

gcsecomputerscience.co.uk Version D Mark Scheme (Section B)

Question	Answer / Indicative Content	Mark	Guidance
5 (a)	1 mark per point: OS uses device drivers to communicate with the touchscreen [1] OS monitors for input events (touches) from the screen [1] OS sends output data (images/text) to the display [1] Provides an interface between the hardware and the application software [1]	4	Link to "touchscreen kiosks".
5 (b)	Encryption: Scrambles archive data using an algorithm/key [1] so it cannot be read by unauthorised users if intercepted during transmission [1]. Compression: Reduces the physical file size of the archives [1]. Allowing more data to be stored on limited disk space // Speeding up transmission over the network [1].	6	AO2: Must link to "museum archives" or "transmission".
6 (a)	1 mark per point (max 6): Open Source: Free to download/use [1]. Access to source code allows full customisation [1]. Support relies on a community of volunteers [1]. Proprietary: Costs money for a licence [1]. Source code is restricted and cannot be changed [1]. Support is provided by the professional developer company [1].	6	Must cover Cost, Support, and Customisation for full marks.
6 (b)	(i) Copyright, Designs and Patents Act 1988 [1] - Correct name is essential [1]. (ii) Computer Misuse Act 1990 [1] - Correct name is essential [1].	4	Award 2 marks per row for full name of Act.
7 (a)	1 mark per point: MAC address is unique to the NIC/Hardware [1] and is permanent/cannot be changed [1]. IP address is assigned by the network/router [1] and can be changed/is dynamic [1].	4	Must refer to both purpose/nature and permanence.

gcsecomputerscience.co.uk Version D Mark Scheme (Section B Continued)

Question

Answer / Indicative Content

Mark

Guidance

7 (b)*

Mark Band 3 (6-8 marks): Thorough knowledge. Balances Cultural vs Environmental. Links stakeholders explicitly. Reference to the Digital Divide is clear and accurate. Clear logical structure.

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

Indicative Content:

Cultural: Preserves artifacts for future generations. Removes barriers (Digital Divide) for those who cannot travel. Potential loss of local jobs/heritage site funding.
Environmental: Energy consumption of massive data centers required to host the HD archives. Reduced carbon footprint from visitors no longer traveling to site. E-waste from kiosks.
Stakeholders: Local Community (Jobs), Global Public (Access), Museum Trustees (Funding), Environmental Groups.

8

AO2 (4) / AO3 (4)

8 (a)

1 mark per point:

Divides a complex task (network communication) into manageable sub-tasks [1].
Each layer provides a service to the layer above it [1].
Each layer is independent, meaning a change in one does not affect the others [1].
Allows different hardware/software to communicate using common standards [1].

4

Focus on "modularity" and "independence".

8 (b)

Sending alert: SMTP [1]
Retrieving/Deleting: POP // POP3 [1]
Syncing devices: IMAP [1]

4

1 mark for 2 correct, 2 marks for all 3 correct. Total 4 marks for row completion.

TOTAL MARKS: 80