3.4 Computer SystemsKey Facts

Quick Reference - Key Points

Part of RAM and ROM · GCSE GCSE Computer Science revision

This key facts covers Quick Reference - Key Points within RAM and ROM for GCSE Computer Science. Revise RAM and ROM in 3.4 Computer Systems for GCSE Computer Science with 16 exam-style questions and 16 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 10 of 11 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 10 of 11

Practice

16 questions

Recall

16 flashcards

Quick Reference - Key Points

RAM Summary:

  • Volatile - loses data when power off
  • Read/write - fast in both directions
  • Stores: running programs, open files, OS, active data
  • Temporary - cleared on shutdown
  • Larger capacity (4GB-32GB typical)

ROM Summary:

  • Non-volatile - keeps data without power
  • Read-only - cannot easily change (or very slow write)
  • Stores: BIOS/UEFI, boot instructions, firmware
  • Permanent - rarely changes (firmware updates only)
  • Smaller capacity (few MB typical)

Memory Hierarchy (Fastest to Slowest):

  1. CPU Registers: Tiny (bytes), inside CPU, fastest
  2. CPU Cache (L1/L2/L3): Small (KB-MB), on CPU, very fast
  3. RAM: Medium (GB), main memory, fast
  4. ROM: Small (MB), firmware storage, moderate speed
  5. SSD: Large (GB-TB), permanent storage, slower than RAM
  6. HDD: Largest (TB), permanent storage, slowest

Keep building this topic

Read this section alongside the surrounding pages in RAM and ROM. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for RAM and ROM

Which of the following best describes RAM?

  • A. Non-volatile memory that stores the BIOS
  • B. Volatile memory that loses data when power is switched off
  • C. Permanent memory that cannot be changed
  • D. Secondary storage used to hold the operating system permanently
1 markfoundation

Explain why the BIOS must be stored in ROM rather than RAM.

2 marksstandard

Quick Recall Flashcards

What does ROM stand for?
Read Only Memory
What does RAM stand for?
Random Access Memory

16 questions on RAM and ROM — practise free

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