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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 · 4 marks

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1Describe2 marksPrimary Memory Swap Remove

Computers use main memory (RAM).

Describe the role of main memory (RAM) in the von Neumann stored program concept.

[2 marks]
Mark scheme

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

  • Holds/stores the data and instructions of the program currently being run (1) to be fetched by the CPU during the fetch-decode-execute cycle (1)
  • Instructions and data are loaded/copied from secondary storage into RAM (1) before they can be processed by the CPU (1)
  • Stores the program that is currently running (1) together with the data that it uses (1)
  • Holds the data and instructions that the CPU needs next (1) so the CPU can access them quickly (1)

Allow a response that describes both that RAM holds the current program and that the program was loaded from secondary storage into RAM, provided each statement is linked to a development.

Do not accept responses about cache or registers as the store of the current program.

Do not accept responses that say RAM stores data permanently or that RAM is read-only.

Do not accept 'RAM is where the CPU processes data' (this describes the ALU/registers), or 'RAM stores the operating system' unless it is linked to the program currently being run.

Do not award a second mark for a response that only states that RAM holds data and instructions with no linked development.

Example answers and how they were marked
Full marks2/2

RAM holds the data and instructions of the program that is currently running so that the CPU can fetch them during the fetch-decode-execute cycle.

Why: Linked point (1): holds data and instructions of the current program, plus linked development (1): fetched by the CPU in the cycle.

Some marks1/2

RAM holds the data and instructions that the computer is using at the moment.

Why: States the role (1) but gives no linked development, so only the first mark is awarded.

No marks0/2

RAM is the secondary storage, so the program is kept there when the power is switched off.

Why: Confuses main memory with secondary storage and says contents are kept without power; both near-misses are named in the 'Do not accept' lines, so no mark.

2Explain2 marksTopologies Swap Remove

A bus topology has a terminator at each end of its cable.

Explain why terminators are needed in a bus topology.

[2 marks]
Mark scheme

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

  • Terminators absorb the signal at the ends of the cable (1) so it is not reflected back along the bus (1)
  • Terminators prevent signals reflecting/bouncing back (1) so the reflected signal does not corrupt data on the cable (1)
  • Terminators absorb the signal (1) so it does not collide/interfere with data being sent by other devices (1)
  • Terminators stop the signal reflecting back down the cable (1) so data can be transmitted and received without errors (1)

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

Allow 'interfere'/'corrupt' only where the answer says the reflected signal mixes with/collides with data on the cable.

Do not accept 'to stop the signal' on its own, as stopping the signal is not the same as stopping it reflecting back along the cable.

Do not accept 'to terminate the cable/network', 'to end the cable' or 'to stop the cable breaking'.

Do not award responses that only repeat the stem, e.g. 'because there is a terminator at each end'.

Example answers and how they were marked
Full marks2/2

Terminators absorb the signal at each end of the cable so that it does not reflect back along the bus.

Why: Linked point (1) and reason (1): absorbing the signal is linked to it not being reflected back along the bus.

Some marks1/2

Terminators absorb the signal at the ends of the cable.

Why: Awarded 1 mark for the point that the signal is absorbed, but no linked consequence is given.

No marks0/2

They terminate the network so the cable does not break.

Why: No credit: it does not say the signal is absorbed or that reflections are prevented, and the mark scheme rejects 'to terminate the network' and 'to stop the cable breaking'.

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