Overview
Computer Science papers look unpredictable until you notice the same mark patterns: trace tables, complexity justification, SQL, logic gates, and pseudocode that must match the scheme word for word. This guide ranks high-frequency topics across 9618 (A-Level), 0478 (IGCSE), and 2210 (O-Level) from 2019—2025 sessions.
Key takeaway: CS marks come from precise terminology and trace accuracy — not "almost right" algorithms.
How this list was built
For Cambridge Cambridge past paper revision, we weighted:
- Frequency across theory and problem-solving papers
- Mark allocation on structured questions
- Examiner report notes on common lost marks
- Practical/paper 2-style skills where applicable
Confirm your syllabus code with your centre.
A-Level Computer Science (9618)
Practise: One trace table per day without looking at the mark scheme first — then mark line by line.
| Priority | Topic | Why it repeats |
|---|---|---|
| 1 | Algorithm tracing & dry runs | Stacks, queues, lists — state tables every series |
| 2 | Big O / time complexity | Justify with operations counted, not intuition |
| 3 | Recursion & iteration | Base case, call stack, rewrite between forms |
| 4 | Trees, graphs & traversals | BST operations, Dijkstra-style steps |
| 5 | Object-oriented design | Classes, inheritance, encapsulation scenarios |
| 6 | Database normalisation & SQL | 1NF—3NF, SELECT/JOIN queries |
| 7 | Boolean algebra & logic circuits | Karnaugh-style simplification |
| 8 | Networks & protocols | TCP/IP layers, packet switching comparisons |
Full guide: 9618 past papers · 9618 boundaries 2026
IGCSE Computer Science (0478)
Guide: [0478 past papers](/blog/cambridge-0478-igcse-computer-science-past-papers-guide).
| Priority | Topic | Notes |
|---|---|---|
| 1 | Pseudocode tracing | Variable states; off-by-one errors |
| 2 | Flowcharts & selection/iteration | Convert between representations |
| 3 | Binary, hex & data representation | Two's complement, image/sound encoding |
| 4 | Logic gates & truth tables | Combine gates; simplify expressions |
| 5 | Networks & security | Threats, encryption basics, topologies |
| 6 | Databases & SQL | Keys, relationships, simple queries |
| 7 | HTML/CSS basics | Structure vs presentation |
| 8 | Ethics & legislation | Short structured responses |
O-Level Computer Science (2210)
Guide: [2210 past papers](/blog/cambridge-2210-o-level-computer-science-past-papers-guide).
| Priority | Topic | Notes |
|---|---|---|
| 1 | Algorithm design & tracing | Same discipline as 0478, deeper traces |
| 2 | Programming concepts | Procedures, parameters, scope |
| 3 | Binary arithmetic | Addition, shifts, overflow |
| 4 | Logic circuits | Build from expression |
| 5 | Hardware & fetch-execute | CPU components, registers |
| 6 | Storage & file types | Lossy vs lossless, compression |
| 7 | Networks | LAN/WAN, protocols, email model |
| 8 | Systems analysis basics | Inputs/outputs, validation |
The 4-week high-yield rotation
For Cambridge Cambridge past paper revision, cross-links: [command words](/blog/cambridge-command-words-past-papers-guide), [fixing silly mistakes](/blog/fixing-silly-mistakes-cambridge-past-papers).
| Week | Mon—Wed | Thu—Fri | Weekend |
|---|---|---|---|
| 1 | Trace tables —5 | Half theory paper | Mark every lost line |
| 2 | SQL + normalisation | Programming Q | Rewrite worst trace |
| 3 | Logic + complexity | Full timed paper | Examiner report |
| 4 | Mixed synoptic | Full timed paper | Upload to MarkScheme |
Sibling guides: Sciences — Economics — Maths — History — English — Media Studies
What "most repeated" does not mean
This section covers What "most repeated" does not mean — ranked by what Cambridge examiners return to most often in past papers.
- Pseudocode syntax must match what your syllabus expects — check the learner guide
- Programming questions punish edge cases — test empty input, bounds
- Theory recall without application scores low on problem-solving papers
FAQ
For Cambridge Cambridge past paper revision, no — cover the full syllabus once, then weight traces and SQL in the final month.
Should I only revise this table?
How do I practise programming for theory papers?
Write pseudocode on paper under time — exams rarely reward IDE autocomplete habits.
Is AI useful for CS revision?
For explaining a missed trace step — yes. For generating answers to memorise — risky; schemes want specific steps.