This key facts covers MDR - Memory Data 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 5 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 5 of 7
Practice
15 questions
Recall
10 flashcards
MDR - Memory Data Register
- Purpose: Holds the actual DATA being transferred between CPU and memory
- Connected to: The Data Bus
- Direction: Two-way - can receive data FROM memory OR send data TO memory
- Contains: Instructions or data values
- Think: "WHAT did I find?" or "WHAT do I want to store?"
Real-world analogy
MDR is like a delivery person's hands - they can carry a package FROM the warehouse to you, or carry something FROM you back to the warehouse.