3.4 Computer SystemsKey Facts

MAR vs MDR - Quick Comparison

Part of MAR, MDR & Registers · GCSE GCSE Computer Science revision

This key facts covers MAR vs MDR - Quick Comparison within MAR, MDR & Registers for GCSE Computer Science. Revise MAR, MDR & Registers in 3.4 Computer Systems for GCSE Computer Science with 15 exam-style questions and 10 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 6 of 8 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 8

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!

Keep building this topic

Read this section alongside the surrounding pages in MAR, MDR & Registers. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for MAR, MDR & Registers

What does MAR stand for?

  • A. Memory Access Register
  • B. Memory Address Register
  • C. Memory Arithmetic Register
  • D. Main Address Register
1 markfoundation

Explain the difference between the MAR and the MDR.

2 marksstandard

Quick Recall Flashcards

What does MDR hold?
The actual data being transferred (WHAT)
What does MAR hold?
The address of data to be read/written (WHERE)

15 questions on MAR, MDR & Registers — practise free

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