What to revise: OCR J277/01
- 1.1 Systems architecture: CPU components, performance and embedded systems.
- 1.2 Memory and storage: primary and secondary storage, units and capacity calculations.
- 1.3 Computer networks, connections and protocols: networks, topology and communications.
- 1.4 Network security: threats and preventative measures.
- 1.5 Systems software: operating-system and utility software.
- 1.6 Ethical, legal, cultural and environmental impacts: considered, scenario-based explanations.
Use the OCR specification pathway to check more detailed subtopics; this page is a revision starting point, not a substitute for the specification.
Worked example: secondary storage capacity
If a device stores 400 image files of 2 MB each, the total is 800 MB, ignoring filesystem overhead. In real exam questions, check whether decimal or binary units are specified; do not mix up bits and bytes.
Try without notes: Name two factors that affect CPU performance and explain their effects. 4 marks
Check an example answer and feedback
Clock speed affects the number of cycles per second; a higher clock speed can allow more processing cycles. Cache size can reduce the need to fetch commonly used instructions or data from slower memory. Actual performance also depends on architecture and workload.
How to revise this paper
- Recall the key terms for one topic without notes.
- Draw one diagram from memory, such as the CPU cycle or a network.
- Practise one calculation with working and units.
- Answer an original explain-or-compare question; check for precise terminology.
- Revisit the same topic later with a different scenario.
Helpful resources: binary and hexadecimal, network revision and written-answer technique.
Official specification
OCR J277 specification at a glance. Assessment is 80 marks, 1 hour 30 minutes, worth 50% of the GCSE; check school arrangements for mocks.