Exclusive Practice Resource

Monday 18 May 2026 - Afternoon

GCSE (9-1) Computer Science

Unofficial Practice Paper: J277/01 Computer Systems [VERSION B]

Time allowed: 1 hour 30 minutes

Centre number
Candidate number
First name(s)
Last name

INSTRUCTIONS

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).
Turn over
2
1

(a) Explain how Cache memory affects CPU performance.

[2]

(b) Explain how the number of Cores affects CPU performance.

[2]

(c) Explain how Clock Speed affects CPU performance.

[2]
2

The CPU contains several special-purpose registers.

(a) State the purpose of the Program Counter (PC).

[2]

(b) State the purpose of the Accumulator.

[2]
Turn over
3
3

(a) Images stored on a computer contain metadata.

State two examples of metadata stored with an image.

1.

2.

[2]

(b) Calculate the file size in Kilobytes (KB) of an image with a resolution of 1000 × 500 pixels and a colour depth of 8 bits. Show your working.

Answer: KB

[4]
4

A school is archiving its old student records.

(a) Justify the use of Magnetic storage rather than Optical storage for archiving these records.

[4]

(b) State two characteristics of secondary storage to consider, other than capacity or cost.

1.

2.

[2]
Turn over
4
5

(a) The school uses compression software before archiving files.

State the purpose of compression software.

[2]

(b) Compare lossy and lossless compression.

[4]
6

(a) Convert the binary number 10101111 to hexadecimal.

[2]

(b) Convert the hexadecimal number 3E to binary.

[2]

(c) Add the following two 8-bit binary numbers. Show your working.

0 1 0 1 0 1 0 1
+ 0 0 1 1 0 0 1 1
[4]

(d) Explain what an overflow error is in binary addition.

[4]
Turn over
5
7

A hospital uses a Star topology for its network.

(a) Describe two benefits of using a Star topology.

Benefit 1:

Benefit 2:

[4]

(b) The hospital stores some patient data using Cloud computing.

Explain two benefits to the hospital of using Cloud computing.

Benefit 1:

Benefit 2:

[4]
8

(a) Describe the social engineering threat known as Phishing.

[3]

(b) Describe how SQL Injection could be used to compromise the hospital's database.

[3]
Turn over
6
9

(a) Explain how a Firewall helps protect the hospital network.

[3]

(b) Explain the purpose of Anti-malware software.

[3]
10

(a) The hospital is choosing between open source and proprietary software.

Compare open source and proprietary software.

[4]

(b) Identify two offences under the Computer Misuse Act 1990.

1.

2.

[2]
11

(a) Explain the concept of layers in the TCP/IP stack.

[4]

(b) State what a MAC address is used for on a network.

[2]
Turn over
7
12*

The hospital is considering using Artificial Intelligence (AI) software for medical diagnosis.

Discuss the impacts of using AI software for medical diagnosis.

Your answer should consider:

[8]
END OF QUESTION PAPER