Identify the CPU component that decodes instructions during the fetch-decode-execute cycle.
Mark scheme
- B Control unit (1)
- The only correct answer is B. The correct answer is control unit.
- A is not correct because the arithmetic logic unit performs arithmetic and logical operations, not decoding
- C is not correct because main memory stores instructions and data, not decoding
- D is not correct because a register holds data or addresses temporarily, not decoding
Example answers and how they were marked
Full marks1/1
B Control unit
Why: Correct option: the control unit decodes instructions (1).
No marks0/1
D Register
Why: Near-miss: a register holds data or addresses temporarily, it does not decode instructions (0).
No marks0/1
A Arithmetic logic unit
Why: Misconception: the arithmetic logic unit performs arithmetic and logical operations; it does not decode (0).