This key facts covers MAR - Memory Address Register within MAR & MDR for GCSE Computer Science. Revise MAR & MDR in Systems Architecture for GCSE Computer Science with 15 exam-style questions and 10 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 4 of 7 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 4 of 7
Practice
15 questions
Recall
10 flashcards
MAR - Memory Address Register
- Purpose: Holds the ADDRESS of the memory location the CPU wants to access
- Connected to: The Address Bus
- Direction: One-way - CPU writes to MAR, which sends to memory
- Contains: A memory address (like a postcode or house number)
- Think: "WHERE do I need to look?"
Real-world analogy
MAR is like the GPS coordinates you type into your sat nav - it tells the system WHERE to go, not what's there.