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IB Computer Science Past Papers & Drilling (Paper 1): Binary, Packet Switching, Normalisation
TUTORZONE ORIGINAL DRILLING MOCK · IB COMPUTER SCIENCE PAPER 1 (2027 SYLLABUS)
Written to the IB 2027 syllabus: Paper 1 (Theme A concepts + pre-seen case study) SL 50 marks, 1 h 15 min, 35% (Section A concepts 38 marks + Section B case study 12 marks); HL is 80 marks, 2 hours, 40%. The old Paper 3 has been removed. This is a Paper 1 drilling mock with answers and techniques.
What is in IB Computer Science Paper 1?
Direct answer: 2027 syllabus Theme A concepts plus the pre-seen case study – SL 50 marks, 1 h 15 min, 35%; HL 80 marks, 2 hours, 40%.
Assessment at a glance (2027)
| Component | Content | Weighting | Duration |
|---|---|---|---|
| Paper 1 (Theme A + case study) | SL 50 marks (A 38 + B 12) | SL 35%／HL 40% | SL 1 h 15 min / HL 2 h |
| Paper 2 (Theme B computational thinking) | SL 50 marks (HL 80) | SL 35%／HL 40% | SL 1 h 15 min / HL 2 h |
IB Computer Science Paper 1 drilling technique: answer the command term exactly (outline gives the shape, explain gives mechanism plus consequence); show every step of binary/hex conversion (method marks survive); Section B case-study answers must cite specifics from the scenario – generic answers score nothing. Paper 3 no longer exists from 2027.
How this paper was built
This is a TutorZone original drilling mock: the questions follow the IB Computer Science Paper 1 format and the answers are our own, not IB past papers, marking references or IB publications.
Pacing
| Section | Marks | Suggested time | What to do first |
|---|---|---|---|
| Paper 1 (Theme A + case study) | SL 35%／HL 40% | about 55 min Section A, 20 min Section B | concepts + case study analysis |
| Paper 2 (Theme B computational thinking) | SL 35%／HL 40% | includes an algorithmic-thinking question with no code | tracing + coding + databases |
Is there still a Paper 3?
Direct answer: no. From first assessment in 2027 Paper 3 has been removed – only Paper 1, Paper 2 and the IA remain.
Paper 1: Section A (38 marks) + Section B case study (12 marks)
Answer the command term; show conversion steps; cite the scenario.
Question 1 (10 marks)
Explain the relationship between binary and hexadecimal, and convert binary 10110110 to hexadecimal.
Question 2 (10 marks)
Describe how packet switching works and state two of its advantages.
Question 3 (10 marks)
Explain the purpose of database normalisation and state the requirement for 2NF.
Question 4 (8 marks)
Distinguish supervised from unsupervised machine learning, with an example of each.
Question 5 (6 marks)
[Case study] From the scenario, identify two input methods the system uses and explain one benefit of each.
Question 6 (6 marks)
[Case study] Evaluate one potential risk of adding machine learning to the scenario’s system and suggest one mitigation.
How do I convert binary to hexadecimal?
Direct answer: group four bits from the right (1011 = B, 0110 = 6), so 10110110 = B6.
Paper 1 answers and marks
Question 1
Hex groups binary four bits at a time (4); 10110110 -> 1011 0110 -> B6 (6).
Question 2
Data is split into packets, each routed independently and reassembled at the destination (6). Advantages: (1) packets can re-route around failures (2); (2) efficient shared use of links (2).
Question 3
Purpose: reduce data redundancy and update anomalies (5). 2NF: in 1NF and every non-key attribute fully depends on the primary key (no partial dependency) (5).
Question 4
Supervised: trained on labelled data (e.g. spam classification) (4). Unsupervised: no labels, finds structure itself (e.g. customer clustering) (4).
Question 5
Must refer to specifics of the scenario (e.g. sensor input, barcode scanning); 3 marks per method plus benefit.
Question 6
Risk (3), e.g. biased training data leading to unfair outcomes; mitigation (3), e.g. regularly audit model outputs and broaden/balance the training data. Must tie back to the scenario.
Which topics does this paper drill?
Direct answer: binary/hex conversion, packet switching, database normalisation, machine-learning types and case-study analysis.
Where these marks are usually lost
| Mistake | What it looks like | What it costs | Instead |
|---|---|---|---|
| Binary conversion without steps | Final answer only | Show each 4-bit grouping | method marks |
| Generic case-study answer | Theory only | Must cite scenario specifics | cite the scenario |
| Command terms treated alike | Outline written long | Outline gives only the shape | answer the command term |
| Still drilling Paper 3 | Using legacy material | Paper 3 removed from 2027 | only Papers 1 and 2 |
How to use this paper
First drill: the full 1 h 15 min (55 min Section A, 20 min Section B) with no notes.
Mark it: check command terms, conversion steps and case-study citations.
Second drill: redo three to seven days later, aiming to finish inside 1 hour.
What should I do after drilling this paper?
Direct answer: log answers missing steps or scenario citations; redo in three to seven days; and drill Paper 2 (Theme B).
FAQ
Is this an IB past paper?
No. The questions and answers are TutorZone originals, not IB past papers, marking references or IB publications.
What is in IB Computer Science Paper 1?
2027 syllabus: Theme A concepts plus the pre-seen case study. SL 50 marks, 1 h 15 min, 35%; HL 80 marks, 2 hours, 40%.
Is there still a Paper 3?
No. From first assessment in 2027, Paper 3 has been removed – only Paper 1, Paper 2 and the IA remain.
Official references
| Resource | What to check |
|---|---|
| IB Computer Science curriculum update (IBO) | Confirm the Paper 1/2 marks and times |
| https://www.tutorzone.com.hk/en-ib-psychology-paper-1-mock-2027/ | IB Psychology Paper 1 drilling mock |
Related: IB Computer Science Paper 2 drilling mock (Theme B) · IB Computer Science drill guide (two-paper order, 75-minute pacing) · practice area · IB Physics drilling mock
Next step: find a tutor / register as a tutor
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