Cambridge IGCSE Computer Science Tutors Online

Cambridge IGCSE Computer Science is syllabus 0478. This page works from the syllabus for exams in 2026, 2027 and 2028. Exams are available in the June and November series, and also in the March series in India.

All candidates take two components, and all candidates are eligible for grades A* to G. There is no Core and Extended tier, so every student sits the same papers.

The two papers split the syllabus cleanly by topic, which is unusual and makes revision planning straightforward. Paper 1 examines Topics 1 to 6, the Computer systems half. Paper 2 examines Topics 7 to 10, the Algorithms, programming and logic half.

Paper 1 is Computer Systems. It lasts 1 hour 45 minutes, carries 75 marks and is worth 50% of the qualification. It contains short-answer and structured questions on Topics 1 to 6, and all questions are compulsory.

Paper 2 is Algorithms, Programming and Logic. It also lasts 1 hour 45 minutes, carries 75 marks and is worth 50%. It contains short-answer and structured questions on Topics 7 to 10, and all questions are compulsory. The syllabus states that the questions require candidates to have practical programming experience, and that knowledge of programming language syntax is not examined, because in all cases the logic is more important than the syntax.

That last sentence is worth reading twice. A student does not need to write flawless Python or Java. A student does need to be able to design a working algorithm and express it clearly, because the final question in Paper 2 is a 15 mark unseen scenario question. It uses the methods and concepts listed in Topics 7 to 10, and candidates are required to write an algorithm using pseudocode or program code for the context provided.

So a fifth of Paper 2 is a single applied question that a student cannot prepare by memorising a specific answer. It is the part of the qualification that most rewards practice, because the skill is building a solution to a problem the candidate has never seen.

Calculators are not allowed in either examination.

There is no coursework and no non-exam assessment. Both components are externally assessed written papers. The syllabus does add, however, that Computer Science is a practical subject and that a range of practical exercises must be integral to the teaching, so the practical work is expected even though it is not separately examined.

The subject content is organised into ten topics across two halves. The Computer systems half covers Topic 1 Data representation, Topic 2 Data transmission, Topic 3 Hardware, Topic 4 Software, Topic 5 The internet and its uses, and Topic 6 Automated and emerging technologies. The Algorithms, programming and logic half covers Topic 7 Algorithm design and problem-solving, Topic 8 Programming, Topic 9 Databases, and Topic 10 Boolean logic.

The detail inside those topics is substantial. Data representation covers binary, hexadecimal, logical shifts and two's complement, how text, sound and images are converted to binary, how data storage is measured, how to calculate the file size of an image and a sound file, and why and how data is compressed. Data transmission covers error checking including parity byte and parity block checks, check digits and automatic repeat query, and encryption including symmetric and asymmetric encryption.

Hardware covers the processor, cores, cache and instruction sets, embedded systems, input and output devices, primary and secondary storage, magnetic, optical and solid-state storage, virtual memory and cloud storage. Software covers system software and applications, operating systems, how hardware, firmware and applications work together, interrupts, high-level and assembly languages, compilers and interpreters, and the role of an IDE. The internet topic covers the internet, URLs, web browsers, how web pages are located and retrieved, and web pages themselves.

The programming half covers algorithm design and problem-solving, programming including the standard constructs, databases and Boolean logic. The syllabus also sets out the pseudocode it uses, including font, indentation and keyword style, and it prints the flowchart symbols and logic gate symbols that candidates are expected to recognise and use. Because the pseudocode notation is specified by the syllabus, students are taught to read and write in that exact style rather than in the style of whichever language they happen to know.

The assessment objectives are three. AO1 is demonstrating knowledge and understanding of the principles and concepts of computer science. AO2 is applying that knowledge and understanding to a given context, including the analysis and design of computational or programming problems. AO3 is providing solutions to problems by evaluating computer systems, making reasoned judgements and presenting conclusions.

The overall weightings are AO1 at 40 per cent, AO2 at 40 per cent and AO3 at 20 per cent of the qualification.

The per paper weightings show why the two papers feel so different. Paper 1 is 60 per cent AO1, 20 per cent AO2 and 20 per cent AO3. Paper 2 is 20 per cent AO1, 60 per cent AO2 and 20 per cent AO3.

So application flips from a fifth of Paper 1 to more than half of Paper 2. A student who is strong on facts about hardware, storage and data representation can do well on Paper 1 while struggling badly on Paper 2, because Paper 2 is asking for design and problem solving, not recall.

The qualification is graded A*, A, B, C, D, E, F or G, with A* the highest and G the lowest. A candidate whose performance does not meet the standard required for grade G is ungraded, which is reported on the statement of results but not on the certificate.