OCR GCSE Computer Science Exam Questions

1.1 Systems Architecture

1.1 question 6

Complete the table by writing the missing definition or name of each common CPU component/register.

CPU Component/Register	Definition
	Stores the address of the next instruction to be fetched from memory; increments each cycle.
CU (Control Unit)
	Stores the address of the data to fetch or where to store data.
	Performs mathematical and logical operations.

MARKS

Mark scheme

PC: Next‑instruction address (increments).
CU: Coordinates/controls processor, decodes in CIR/runs FDE.
MAR: Address for memory access (read/write).
ALU: Performs maths/logic.

Exam guidance

Read full CU answer and award appropriate point; ‘sends signals’ alone is insufficient.