Specification Map & Revision Checklist
This lesson provides a comprehensive map of the AQA GCSE Computer Science specification (8525), showing exactly what is tested on each paper, which topics appear most frequently, the key formulas you need to remember, and a full revision checklist to track your progress.
AQA GCSE Computer Science Specification Map (8525)
The specification is divided into the following major sections. Understanding where each topic sits helps you plan targeted revision.
Paper 1 Topics — Computational Thinking and Programming Skills
| Spec Section | Topic | Key Content |
|---|
| 3.1 | Fundamentals of Algorithms | Representing algorithms (pseudocode, flowcharts), searching (linear, binary), sorting (bubble, merge, insertion) |
| 3.2 | Programming | Data types, programming concepts (sequence, selection, iteration), string handling, subroutines, file handling, records, SQL, arrays/lists, 2D arrays |
| 3.3 | Fundamentals of Data Representation | Number bases (binary, hex, denary), binary arithmetic, shifts, character encoding, image representation, sound representation, compression |
Paper 2 Topics — Computing Concepts
| Spec Section | Topic | Key Content |
|---|
| 3.4 | Computer Systems | Hardware/software, Boolean logic, software classification, systems architecture (CPU, fetch-decode-execute), memory, storage |
| 3.5 | Fundamentals of Computer Networks | Network types (LAN, WAN), network topologies, wired/wireless, protocols, TCP/IP layers, network security |
| 3.6 | Cyber Security | Threats, prevention, social engineering, malware |
| 3.7 | Relational Databases and SQL | Database concepts (primary key, foreign key, entity, attribute), SQL queries (SELECT, INSERT, UPDATE, DELETE, WHERE, AND, OR, wildcards) |
| 3.8 | Ethical, Legal, and Environmental Impact | Legislation, ethical issues, environmental impact, privacy, digital divide |
Important: Some topics can appear on either paper. Specifically, data representation (3.3) content can appear on Paper 1 and Paper 2. SQL is primarily in Paper 2 but programming-style SQL questions can appear on Paper 1. Always revise all topics for both papers.
Paper 1 vs Paper 2 Topic Split — Detailed View
Paper 1 Focus Areas
| Topic | What to Practise | Question Type |
|---|
| Algorithm design | Write pseudocode/flowcharts for given problems | Design questions (4–8 marks) |
| Trace tables | Trace pseudocode/Python with specific inputs | Completion questions (3–6 marks) |
| Code writing | Write Python/pseudocode programs from a brief | Code writing (4–8 marks) |
| Debugging | Identify and fix errors in given code | Error identification (2–4 marks) |
| Searching algorithms | Trace/describe linear and binary search | Short answer + trace (2–6 marks) |
| Sorting algorithms | Trace/describe bubble, merge, insertion sort | Short answer + trace (2–6 marks) |
| String manipulation | Write code to process strings | Code writing (3–5 marks) |
| File handling | Read/write files in code | Code writing (3–5 marks) |
| Subroutines | Write and use functions with parameters | Code writing (3–6 marks) |
| Arrays and lists | Process data in arrays/lists | Code writing (3–6 marks) |
Paper 2 Focus Areas
| Topic | What to Practise | Question Type |
|---|
| Systems architecture | CPU components, FDE cycle, Von Neumann | Short answer + explain (2–4 marks) |
| Memory and storage | RAM/ROM/cache, storage types comparison | Comparison + explain (2–4 marks) |
| Boolean logic | Truth tables, logic gates, expressions | Completion + calculation (2–6 marks) |
| Networks | Topologies, protocols, TCP/IP layers | Describe + explain (2–6 marks) |
| Security | Threats and prevention methods | Describe + explain (2–6 marks) |
| Data representation | Conversions, file size calculations | Calculation + explain (2–6 marks) |
| Ethical/legal | Legislation, ethical arguments | Discuss/evaluate (4–6 marks) |
| Databases and SQL | Write SQL queries, describe concepts | Code writing + explain (2–6 marks) |
High-Frequency Topics from Past Papers
Based on analysis of recent AQA GCSE Computer Science papers, these topics appear with the highest frequency:
Topics That Appear Almost Every Year
| Topic | Paper | Typical Question Type |
|---|
| Binary/hex/denary conversions | 1 or 2 | Calculation (2–3 marks) |
| Binary addition | 1 or 2 | Calculation (2–3 marks) |
| Image file size calculation | 1 or 2 | Calculation with explanation (3–4 marks) |
| Trace tables | 1 | Completion (4–6 marks) |
| Code writing (input validation) | 1 | Programming (4–6 marks) |
| Linear vs binary search comparison | 1 | Comparison/explain (3–4 marks) |
| Sorting algorithm trace | 1 | Trace/describe (3–6 marks) |
| CPU components and FDE cycle | 2 | Describe/explain (3–5 marks) |
| Star vs mesh topology | 2 | Comparison (3–4 marks) |
| Network protocols | 2 | State/describe (2–3 marks) |
| Security threats and prevention | 2 | Describe/explain (4–6 marks) |
| Truth tables and logic gates | 2 | Completion (2–4 marks) |
| Ethical/legal/environmental issues | 2 | Discuss (4–6 marks) |
Topics That Appear Frequently (Most Years)
| Topic | Paper | Notes |
|---|
| Sound file size calculation | 1 or 2 | Often combined with quality explanation |
| Lossy vs lossless compression | 1 or 2 | Comparison + contextual example |
| ASCII vs Unicode | 1 or 2 | Explanation question |
| SQL queries | 2 | Write a query to extract data |
| Subroutine design | 1 | Write a function with parameters |
| String manipulation code | 1 | Character counting, substring extraction |
| RAM vs ROM | 2 | Comparison |
| Types of malware | 2 | Describe with examples |
Topics That Appear Less Frequently (But Still Examinable)
| Topic | Paper | Notes |
|---|
| Binary shifts | 1 or 2 | May appear as part of a larger question |
| 2D arrays | 1 | Code writing or trace |
| File handling | 1 | Read from/write to file |
| Virtual memory | 2 | Explain what it is and why it is needed |
| Utility software | 2 | Name and describe utilities |
| Environmental impact | 2 | Discussion question |
| Digital divide | 2 | Discussion question |
Key Formulas to Remember
These formulas are essential and should be memorised:
Image File Size
File size (bits) = width (pixels) × height (pixels) × colour depth (bits per pixel)
Alternatively, if given total number of pixels:
File size (bits) = total pixels × colour depth (bits per pixel)
Sound File Size
File size (bits) = sample rate (Hz) × bit depth (bits) × duration (seconds)
For stereo audio:
File size (bits) = sample rate (Hz) × bit depth (bits) × duration (seconds) × 2
Unit Conversions
| From | To | Operation |
|---|
| Bits | Bytes | ÷ 8 |
| Bytes | Kilobytes (KB) | ÷ 1,024 |
| Kilobytes | Megabytes (MB) | ÷ 1,024 |
| Megabytes | Gigabytes (GB) | ÷ 1,024 |
| Gigabytes | Terabytes (TB) | ÷ 1,024 |
Binary Arithmetic Reference
| Operation | Rule |
|---|
| 0 + 0 | 0 |
| 0 + 1 | 1 |
| 1 + 0 | 1 |
| 1 + 1 | 10 (0, carry 1) |
| 1 + 1 + 1 | 11 (1, carry 1) |
Colour Depth and Number of Colours
Number of colours = 2 ^ colour depth
| Colour Depth | Number of Colours |
|---|
| 1 bit | 2 (black and white) |
| 2 bits | 4 |
| 4 bits | 16 |
| 8 bits | 256 |
| 16 bits | 65,536 |
| 24 bits | 16,777,216 (True Colour) |
Binary Shift Effects
| Shift | Effect |
|---|
| Left shift by n positions | Multiply by 2^n |
| Right shift by n positions | Integer divide by 2^n |
Common Conversion Reference Tables
Powers of 2 (Frequently Used)
| Power | Value | Common Use |
|---|
| 2^0 | 1 | |
| 2^1 | 2 | |
| 2^2 | 4 | |
| 2^3 | 8 | Bits in a byte |
| 2^4 | 16 | Hex digits |
| 2^5 | 32 | |
| 2^6 | 64 | |
| 2^7 | 128 | ASCII characters |
| 2^8 | 256 | Extended ASCII / Byte values |
| 2^10 | 1,024 | 1 KB |
| 2^16 | 65,536 | |
| 2^20 | 1,048,576 | 1 MB |
| 2^24 | 16,777,216 | True Colour |
Hexadecimal Reference