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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 693 exam-style questions, each with its mark scheme and example answers. Print it, or answer it on paper and then open the mark schemes. Or browse the questions by topic.

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2 questions · 3 marks

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1Short recall1 markPrimary Memory Swap Remove

Computers use RAM to store the data and instructions that are in use.

Name the term used to describe memory that loses its contents when the power is switched off.

[1 mark]
Mark scheme

Award one mark for:

  • Volatile (1)

Allow volatile memory / it is volatile.

Do not accept non-volatile, ROM, RAM or temporary/short term memory on their own, as these are not the term asked for.

Example answers and how they were marked
Full marks1/1

Volatile

Why: Correct term for memory that loses its contents when the power is switched off (1).

No marks0/1

Temporary memory

Why: Describes what such memory does but is not the term asked for; 'temporary memory' is on the Do not accept line, so no mark.

No marks0/1

Non-volatile

Why: Non-volatile memory keeps its contents when the power is switched off, the opposite of what the question describes; it is explicitly not accepted.

2Explain2 marksStored Program Computers Swap Remove

The control unit is a component of the CPU.

Explain one role of the control unit in the fetch-decode-execute cycle.

[2 marks]
Mark scheme

Award up to two marks for a linked explanation such as:

  • It decodes instructions (1) so the CPU knows what operation/instruction to perform (1)
  • It sends control signals (1) to coordinate/control the flow of data/instructions between components (1)
  • It manages/directs the fetch-decode-execute cycle (1) by controlling the sequence/timing of the stages (1)
  • It directs the other components of the CPU (1) so that each instruction is fetched/decoded/executed in the correct order (1)

For both marks, the expansion must follow/associate with the statement.

Allow an explanation that the control unit directs data/instructions along the address/data/control buses (1) so the fetch-decode-execute cycle can take place (1)

Do not accept a generic 'it controls the CPU/components' point without linked expansion as to what is controlled/directed.

Do not accept 'it fetches instructions from memory' on its own; credit only if linked to the address/data/control buses or control signals.

Do not accept 'it stores/holds the instruction/data' as this is the role of a register.

Do not accept answers about the ALU performing calculations.

Example answers and how they were marked
Full marks2/2

It decodes instructions so the CPU knows which operation to carry out

Why: Linked point (1) and reason (1).

Some marks1/2

It decodes instructions.

Why: Creditworthy point (1) but no linked reason (0).

No marks0/2

It stores the instructions that are being executed.

Why: Misconception: storing/holding the instruction is the role of a register, not the control unit.

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