This key facts covers MAR vs MDR - Quick Comparison 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 6 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 6 of 7
Practice
15 questions
Recall
10 flashcards
MAR vs MDR - Quick Comparison
| Feature | MAR | MDR |
|---|---|---|
| Stands for | Memory Address Register | Memory Data Register |
| Holds | Address (WHERE) | Data (WHAT) |
| Connected to | Address Bus | Data Bus |
| Direction | One-way (to memory) | Two-way (to/from memory) |
Memory Trick
MAR = Memory Address Register (A for Address - WHERE)
MDR = Memory Data Register (D for Data - WHAT)
A comes before D in the alphabet, just like you need to know the ADDRESS before you can get the DATA!