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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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4 questions · 7 marks

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1Multiple choice1 markStored Program Computers Swap Remove

Identify the function of the control unit in the fetch-decode-execute cycle.

[1 mark]
  • ADecodes instructions
  • BPerforms arithmetic operations
  • CStores data and instructions
  • DTemporarily stores data being processed
Mark scheme
  • A Decodes instructions (1)
  • The only correct answer is A. The correct answer is Decodes instructions.
  • B is not correct because the arithmetic logic unit performs arithmetic operations
  • C is not correct because main memory stores data and instructions
  • D is not correct because registers temporarily store data being processed
Example answers and how they were marked
Full marks1/1

A Decodes instructions

Why: Correct option: the control unit decodes instructions during the fetch-decode-execute cycle (1).

No marks0/1

C Stores data and instructions

Why: Main memory stores data and instructions, not the control unit; this is a common distractor, so no mark.

No marks0/1

B Performs arithmetic operations

Why: Arithmetic operations are performed by the ALU, not the control unit; a common confusion between CPU components, so no mark.

2Short recall2 marksSecondary Memory Swap Remove

A computer uses secondary storage to keep programs and data.

Give two examples of secondary storage devices that store data using magnetic media.

[2 marks]
Mark scheme

Award one mark for any of the following up to a maximum of two marks:

  • Hard disk drive/HDD (1)
  • External/portable hard disk drive (1)
  • Magnetic tape drive (1)
  • Magnetic tape (1)

Allow a named device or the storage media type, e.g. hard disk/hard disc for hard disk drive, tape for magnetic tape

Allow floppy disk/floppy disk drive

Do not accept solid state devices (SSD, USB flash drive/memory stick, SD card/memory card) or optical media (CD/DVD/Blu-ray) as these do not store data using magnetism

Example answers and how they were marked
Full marks2/2

Hard disk drive and magnetic tape

Why: Hard disk drive (1) and magnetic tape (1) are both magnetic secondary storage, so both marks are awarded.

Some marks1/2

Hard disk drive and SD card

Why: Hard disk drive is magnetic (1); an SD card is solid state, not magnetic, so the second mark is not awarded.

No marks0/2

CD and DVD

Why: Both are optical media, which the mark scheme says not to accept, so no marks are awarded.

3Explain2 marksEmbedded Systems Swap Remove

An engine control unit (ECU) in a car is an embedded system.

Explain one benefit of using an embedded system for the engine control unit instead of a general purpose computer.

[2 marks]
Mark scheme

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

  • (The ECU) is more reliable/less likely to crash (1) because it only runs the one program/has a single purpose (1)
  • (The ECU) cannot be affected by other software/viruses (1) because it cannot run other software/it can only run the program it was made for (1)
  • (The ECU) is cheaper (1) because it has limited processing resources/less memory/simple components (1)
  • (The ECU) uses less power (1) because it has limited processing resources/a simpler processor (1)
  • (The ECU) is smaller (1) because it has fewer components/less memory than a general purpose computer (1)

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

A suitable benefit stated on its own earns one mark.

Do not accept a description or a location given as the reason, e.g. 'because it is part of the car', 'because it is inside the engine', 'because it is embedded'.

Do not accept a description of an embedded system on its own as the benefit, e.g. 'it does one specific job' or 'it is part of the car'.

Do not accept 'it is faster'/'it has a more powerful processor' as embedded systems have limited processing resources.

Example answers and how they were marked
Full marks2/2

It is more reliable than a general purpose computer because it only runs the one program so it will not crash and stop the engine working.

Why: Benefit stated (1) with a linked reason (1); the reason shows why only running one program makes it reliable.

Some marks1/2

It is more reliable because it is part of the car's engine.

Why: Only the benefit earns a mark (1); being part of the car is a location, not a linked reason why it is reliable.

No marks0/2

It is faster than a general purpose computer because it is embedded in the engine.

Why: Misconception that an embedded system is faster; embedded systems have limited processing resources, so neither point nor reason is creditworthy.

4Explain2 marksPrimary Memory Swap Remove

A computer follows the von Neumann stored program concept. A program's instructions are stored on secondary storage before the program is run.

Explain one reason why the instructions of a program must be held in RAM before they can be executed.

[2 marks]
Mark scheme

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

  • The CPU can only fetch/read instructions from main memory/RAM (1) so the instructions of a running program must be copied/loaded into RAM before they can be executed (1)
  • RAM is faster to access than secondary storage (1) so the instructions can be fetched quickly enough for the CPU to execute them (1)
  • The CPU needs the instructions in RAM to fetch and execute them (1) because the fetch-decode-execute cycle reads each instruction from main memory/RAM (1)
  • The address of the next instruction is sent to RAM on the address bus (1) so the instruction can be transferred to the CPU/registers for decoding/execution (1)

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

Allow the point and reason in either order if they are linked.

Do not accept answers that only say the CPU needs instructions, or that RAM is faster, without linking this to fetching/executing the instructions.

Do not accept answers that only say RAM holds data and instructions without linking this to the fetch-decode-execute cycle.

Do not accept 'RAM is permanent/non-volatile storage, so the instructions are kept safe' - RAM is volatile.

The response does not need to name the address bus or the fetch stage for full marks; a linked reason that explains why instructions must be in RAM (for example, the CPU can only fetch from RAM, or RAM is faster than secondary storage) is enough.

Example answers and how they were marked
Full marks2/2

The CPU can only fetch instructions from main memory, so the instructions of a running program must be copied into RAM before they can be executed.

Why: Linked point (1) for the CPU only being able to fetch instructions from main memory/RAM, and reason (1) for instructions being copied into RAM before execution.

Some marks1/2

The CPU can only fetch instructions from main memory.

Why: Point (1) only; there is no linked reason that explains why this means the instructions must be held in RAM before execution, such as RAM being faster than secondary storage.

No marks0/2

Instructions are kept in RAM because RAM is permanent storage and does not lose the instructions when the power is turned off.

Why: Misconception: RAM is described as permanent/non-volatile, which the mark scheme's 'Do not accept' line rules out; no creditworthy linked point.

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