Paper 1 · Compulsory Part Overview
Weighting: 55% of the total subject mark · Duration: 2 hours · Format: Section A (MC, 22%) + Section B (short & structured, 33%)
The Compulsory Part is examined in Paper 1. Every student answers the same paper, regardless of which two electives they take in Paper 2. It is therefore the single largest block of marks in the subject and your first revision priority.
The five modules at a glance
| # | Module | Hours | Why it matters |
|---|---|---|---|
| A | Information Processing | 37 | Foundation for Paper 2A. Builds data thinking and Excel/DBMS skills. |
| B | Computer System Fundamentals | 20 | Hardware/software fluency. Predictable MC question source. |
| C | Internet & its Applications | 31 | Networking + security. Foundation for Paper 2B. |
| D | Computational Thinking & Programming | 48 | The biggest module. Sets up Paper 2C and trace-table questions in Paper 1. |
| E | Social Implications | 8 | Short module, high marks-per-hour. Discussion + ethics. |
Total lesson time
The official C&A Guide allocates 144 hours for the Compulsory Part, plus 76 hours for the two electives, plus 30 hours for SBA, for a curriculum total of 250 hours over three years.
Paper 1 structure
┌────────────────────────────────────────────────┐
│ Paper 1 · 2 hours │
├────────────────────────────────────────────────┤
│ Section A · Multiple Choice │
│ - Around 36 MC questions │
│ - Weight: 22% of subject mark │
├────────────────────────────────────────────────┤
│ Section B · Short + Structured Questions │
│ - Mix of one-mark short answers and │
│ multi-part structured questions │
│ - Weight: 33% of subject mark │
│ - SQL command sheet & spreadsheet function │
│ reference table provided in the paper │
└────────────────────────────────────────────────┘2
3
4
5
6
7
8
9
10
11
12
13
14
What gets tested
All learning outcomes from Modules A–E are fair game. The HKEAA tends to mix topics within a single structured question — a long sub-question may start with binary representation (Module A), pivot to network protocols (Module C) and end with a piece of pseudocode tracing (Module D).
Assessment objectives in Paper 1
You will need to demonstrate:
- Knowledge & understanding of computer systems, data, hardware, software and the Internet.
- Application of declarative knowledge to specific scenarios (e.g. selecting the right validation method).
- Analysis of materials — comparing two solutions, tracing through pseudocode, debugging.
- Synthesis — applying multiple concepts to design a new solution.
The action verbs in the C&A Guide map directly onto these objectives:
| Verb family | Cognitive level |
|---|---|
| state, list, define, recognise | Recall |
| describe, explain, identify, demonstrate, apply | Application |
| distinguish, analyse, compare, evaluate | Analysis |
| develop, plan, design, construct | Synthesis |
If a question starts with "Design a function that…" expect to be marked on full implementation logic. If it starts with "State the difference between…" a one-sentence answer is enough.
How to study the Compulsory Part
- Sequence matters. Most teachers teach in the order A → C → B → E → D so that concepts in earlier modules feed into the later ones. If you are self-studying, follow the same order.
- Treat Module D as a coding muscle. You cannot cram coding the night before the exam. Run at least one Python (or C++) program every week from S4 onwards.
- Use spaced repetition for vocabulary. Modules B, C and E are vocabulary-heavy. Flashcards beat re-reading notes.
- Cross-reference with your elective. Concepts in Module A feed Paper 2A, Module C feeds 2B, and Module D feeds 2C — revising them together saves time.
SQL practice in the browser
A surprising number of Paper 1 Section B marks come from reading a short SQL SELECT statement and predicting its output. Run those examples interactively on SQL Books — a free in-browser SQL workspace where every account gets its own MySQL sandbox. No setup, no risk of damaging anything.
Next steps
Pick a module and dive in: