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Monday 18 May 2026 - Afternoon

GCSE (9-1) Computer Science

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

Time allowed: 1 hour 30 minutes

Centre number
Candidate number
First name(s)
Last name

INSTRUCTIONS

Answer all the questions.

The total mark for this paper is 80.

Turn over
2
1

(a) State the full name of the following CPU registers and describe their specific purpose in the Von Neumann architecture.

Program Counter (PC)

Accumulator (ACC)

[5]

(b) A computer has run out of physical RAM and is now using Virtual Memory. Explain how virtual memory works and describe one negative effect of "thrashing" on the system's performance.

[4]

(c) A professional photographer needs to back up 500GB of high-resolution images. Justify the selection of a specific secondary storage device for this application, comparing it against one other type of storage.

[6]
3
2

(a) Define the difference between a Local Area Network (LAN) and a Wide Area Network (WAN). State one example of each.

[5]

(b) Identify and explain three factors that can affect the performance of a network.

1.

2.

3.

[5]
3

(a) Explain the role of Hosting in relation to the World Wide Web.

[2]

(b) Describe what is meant by "The Cloud" and state one benefit of using it for data storage.

[3]

(c) Explain the relationship between Web Servers and Web Clients when a user requests a website.

[5]
4
4

(a) Complete the table below by stating the full name and primary purpose of each network protocol.

ProtocolFull NamePrimary Purpose
FTP
POP
IMAP
SMTP
[10]

(b) Explain the concept of layers in network protocols and state one advantage of using a layered model.

[5]
5
5

(a) Describe how the following network security threats operate:

Denial of Service (DoS) attack:

Data Interception and Theft:

[7]

(b) Identify four different methods of preventing or identifying security vulnerabilities in a network.

1.

2.

3.

4.

[8]
6
6

(a) The Operating System manages many different aspects of the computer. Describe the role of the OS in:

Memory Management and Multitasking:

User Management and File Management:

[6]

(b) Explain the purpose of Utility System Software. Give one example of a utility task.

[4]
7

(a) Contrast Open Source software with Proprietary software. State one benefit of each.

[4]

(b) Identify the specific piece of legislation that makes it illegal to access a computer system without permission.

[1]