OCR A-Level Computer Science (H446): complete guide to the components and the exams

OCR A-Level Computer Science (specification H446) is a two-year linear course assessed by two written papers and a Programming Project. The papers test theory, problem solving and algorithms; the project tests your ability to analyse, design, build and evaluate a real program. This page is the index: below is a map of the content, the assessment structure, and how to study each part.

The OCR Computer Science components

The specification is organised into two examined content areas plus the non-exam project.

Component 01: Computer systems (sections 1.1 to 1.5)

The theory of how computers work and how they fit into society. It covers the structure and function of the processor and its architecture, input, output and storage devices, system and application software, software development methodologies and programming paradigms, exchanging data through compression, encryption, hashing, databases, networks and the web, the representation of data with number systems and Boolean algebra, and the legal, moral, cultural and ethical impact of computing.

Component 02: Algorithms and programming (sections 2.1 to 2.3)

The problem-solving half. It covers the elements of computational thinking (abstraction, decomposition, thinking ahead, procedurally, logically and concurrently), programming techniques including sequence, selection, iteration, recursion, subroutines and object-oriented programming, computational methods, and the standard searching, sorting and pathfinding algorithms analysed with Big-O notation.

Component 03 or 04: Programming Project (NEA)

An independent project worth 20 per cent in which you solve a real problem for a real user through analysis, design, iterative development with testing, and evaluation, evidenced in a coded solution and a written report.

Exam structure

H446 is assessed by two written papers sat at the end of the course, plus the project. No calculator is allowed in either paper.

• Component 01 (Computer systems, H446/01) covers sections 1.1 to 1.5. 2 hours 30 minutes, 140 marks, 40%.
• Component 02 (Algorithms and programming, H446/02) covers sections 2.1 to 2.3. 2 hours 30 minutes, 140 marks, 40%.
• Programming Project (H446/03 or H446/04) is non-exam assessment, internally marked and externally moderated. 20%.

Both papers mix short-answer questions that reward precise recall with extended levels-of-response questions (typically up to 12 marks) marked by best fit against band descriptors.

How to study OCR Computer Science

Computer Science rewards precise definitions, fluent number and Boolean work, and clear algorithm design.

1. Work from the specification statements. Each statement in 1.1 to 2.3 is a checklist; questions are written directly from them.
2. Drill the number and Boolean maths. Binary, hexadecimal, two's complement, floating point, De Morgan's laws and Karnaugh maps must be automatic, because there is no formula booklet.
3. Learn definitions precisely. Mark schemes reward exact wording for terms such as virtual memory, normalisation, ACID, and abstraction.
4. Practise algorithms with trace tables. Searching, sorting and graph algorithms recur with trace-table and Big-O questions; rehearse them in OCR pseudocode.
5. Treat the project as a methodology, not a program. The marks come from analysis, design, iterative testing and evaluation evidence, so document as you build.

The components, dot point by dot point

Each module has specification-statement-level answer pages with worked exam questions and cross-links, plus an overview guide and a check-your-knowledge quiz. Browse the full set at /a-level-ocr/computer-science/syllabus.

For the official specification

OCR publishes the full specification (H446), past papers, mark schemes and the project guidance at ocr.org.uk. Always revise from the current specification and OCR's own past papers, because question style is board-specific.