Imagine you're in a massive library looking for a specific book. First, you write down the shelf number on a slip of paper (that's the MAR - it holds the ADDRESS of where to look). You take that slip to the librarian, who finds the shelf, grabs the book, and hands it to you. You now hold the actual book (that's the MDR - it holds the actual DATA that was found). The MAR says WHERE, the MDR holds WHAT. Simple as that!
This introduction covers The Library Search 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 1 of 8 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for MAR, MDR & Registers
What does MAR stand for?
Explain the difference between the MAR and the MDR.
Quick recall flashcards
What does MAR hold?
The address of data to be read/written (WHERE)
What does MDR hold?
The actual data being transferred (WHAT)