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0478_m26_ms_12 2026 March Computer Science 0478 Mark Scheme 1 Variant 2 · Cambridge CAIE IGCSE

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0478_m26_ms_122026 March Computer Science 0478 Mark Scheme 1 Variant 2

This is the official Cambridge mark scheme for Computer Science (0478) Mark Scheme 1 (Variant 2) from the 2026 March session. Mark schemes show exactly how each mark is awarded, including acceptable alternative answers, required key terms, and common errors that lose marks. Cambridge mark schemes use notation like "allow," "accept," and "do not credit" to define the boundary between full marks and zero.

Also referenced as: 0478_m26_ms_12 · 0478/12/f/m/26 ms · 0478/12 Feb/March 2026 ms

Paper 1: Theory of Computer Science This is Paper 1: Theory of Computer Science, worth 75 marks with a duration of 1h 15m. Short-answer and structured questions covering data representation, hardware, software, security, internet technologies, and ethical issues. No programming required.

This mark scheme corresponds to 0478_m26_qp_12. For maximum revision benefit, attempt the question paper under strict exam conditions first, then use this mark scheme to self-assess. Pay attention to the marking notation: "allow" means an alternative is accepted, "do not credit" means a specific phrasing is rejected even if technically correct, and "ORA" (or reverse argument) means the mark can also be earned with the opposite reasoning.

Cambridge mark schemes reward precise language. For Computer Science (0478), look for keywords the examiner requires — definitions must include specific terms (e.g., "per unit mass," "resultant"), and calculations must show working even if the final answer is correct. Understanding mark scheme conventions helps you write answers that hit every marking point, not just the general idea.

Same paper, other years

Computer Science (0478) Mark Scheme 1 (Variant 2) from other exam sessions — practise the same paper across the years, then check each one against its mark scheme.

Examiner Insights — Paper 1: Theory of Computer Science

Based on analysis of 3 official Cambridge documents (2023, 2025)

1

Not using the context given in the question

Candidates gave generic answers rather than relating their response to the specific scenario described in the question.0478 Paper 1, May/June 2023

How to fix: Always use the scenario from the question in your answer. If the question describes a school library system, write about 'the library database' and 'borrowing records', not generic examples. Examiners want to see that you can apply knowledge to the given context.

2

Repeating information already given in the question stem

A number of candidates restated what the question had already told them rather than adding new information or explanation.0478 Paper 1, May/June 2023

How to fix: Read the question and note what information is already provided. Your answer must add something new. If the question says 'RAM is volatile', do not repeat 'RAM is volatile' — explain what volatile means and why it matters (data is lost when power is turned off).

3

Describing encryption as making data 'unreadable' instead of 'meaningless'

Candidates described encrypted data as 'unreadable' which is incorrect — the data can still be read, but it appears meaningless without the decryption key.0478 Paper 1, May/June 2023

How to fix: Encrypted data is not 'unreadable' — it IS readable, just meaningless without the key. The correct phrasing: 'Encryption converts plaintext into ciphertext that appears meaningless to anyone who intercepts it without the decryption key.' The data can be seen; it just cannot be understood.

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All Computer Science (0478) Papers — 2026 March

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Computer Science Exam Guide: How to Score Higher

Top mistakes, scoring patterns & answer frameworks from 3 official Cambridge documents