Computer Science Revision
Algorithms, programming, data representation, networks, and computer systems.
OCR GCSE Computer Science revision is easier to plan when every topic maps to the J277 specification, and that is how these lessons are organised across both components. Component 01, Computer systems, covers systems architecture, memory and storage, networks, security, system software and the impact of technology, while Component 02, Computational thinking, algorithms and programming, covers algorithms, programming techniques, logic and languages.
Each lesson takes one part of J277 and explains it in clear, exam-ready sections with worked examples for the algorithm and programming content. Generate a quiz or flashcards from any lesson to test yourself, and ask the built-in tutor to step through an algorithm, explain a logic gate, or clarify how memory and storage differ whenever you need it.
Lessons
Systems architecture
26 min
7 min
Memory and storage
37 min
LessonPrimary and Secondary Storage
1.2.1 Primary storage (memory); 1.2.2 Secondary storage
2 months ago
7 min
9 min
LessonData Representation
1.2.4 Data storage (characters, images, sound); 1.2.5 Compression
2 months ago
Computer networks, connections and protocols
29 min
9 min
LessonWired and Wireless Networks, Protocols and Layers
1.3.2 Wired and wireless networks, protocols and layers
2 months ago
Network security
19 min
LessonCyber Security — Threats and Prevention
1.4.1 Threats to computer systems and networks; 1.4.2 Identifying and preventing vulnerabilities
2 months ago
Systems software
17 min
LessonSystems Software — Operating Systems and Utilities
1.5.1 Operating systems; 1.5.2 Utility software
2 months ago
Ethical, legal, cultural and environmental impacts
19 min
LessonEthical, Legal, Cultural and Environmental Impacts of Technology
1.6.1 Ethical, legal, cultural and environmental impact
2 months ago
Algorithms
48 min
8 min
LessonDesigning and Refining Algorithms
2.1.2 Designing, creating and refining algorithms
2 months ago
7 min
9 min
Programming fundamentals
66 min
7 min
6 min
6 min
6 min
7 min
Producing robust programs
27 min
8 min
Boolean logic
16 min
Programming languages and IDEs
19 min
LessonProgramming Languages and IDEs
2.5.1 Languages; 2.5.2 The Integrated Development Environment (IDE)
2 months ago
Frequently asked questions
It is assessed by two written papers, each 1 hour 30 minutes and worth 50%. Paper 1 (J277/01) is Computer systems and Paper 2 (J277/02) is Computational thinking, algorithms and programming.
Paper 1 is the more theory-led paper on how computer systems work, including networks and security. Paper 2 is more practical, testing algorithms, programming techniques and logic, and includes questions where you write or interpret code.
OCR provides an Exam Reference Language for written programming questions, and schools commonly teach Python alongside it. Practising the logic and the reference language is the most reliable preparation.
No. J277 is assessed entirely by the two written exams, with no coursework counting towards your grade. Schools may still set a programming task for practice, since Paper 2 tests your coding on paper.
Yes. Every public lesson is free to read, and a free account lets you generate quizzes and flashcards from them. Pro simply removes the monthly creation limit.
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