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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 604 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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3 questions · 5 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.

2Describe2 marksMemory Management Swap Remove

A program is stored on secondary storage before it is run.

Describe how the operating system manages memory when a program is started.

[2 marks]
Mark scheme

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

  • The program (and its data) is copied/loaded from secondary storage into main memory/RAM (1) so that the CPU can fetch/execute its instructions (1)
  • An area of main memory is allocated/reserved for the program (1) that is large enough to hold the program and its data (1)
  • The operating system checks that there is enough free main memory (1) before the program can be started/loaded, otherwise it cannot run/an error is reported (1)
  • The operating system keeps a record of the memory addresses used by the program (1) so that its instructions and data can be found when it runs (1)

Allow 'loaded into RAM', 'stored in memory' and 'put into main memory' as equivalent to copied into main memory.

A single statement that the program is loaded/stored in main memory, with no linked development, can be given one mark only.

Do not accept descriptions of the CPU fetching/executing instructions that do not refer to the operating system loading or allocating memory.

Do not accept responses about virtual memory (moving processes to secondary storage) or about which process runs next on the CPU.

Do not accept the program being run from secondary storage/hard disk.

Example answers and how they were marked
Full marks2/2

The operating system copies the program and its data from secondary storage into main memory so that the CPU can fetch and execute its instructions.

Why: Copying the program and data into main memory (1) linked to the CPU fetching/executing instructions (1).

Some marks1/2

The operating system loads the program into main memory.

Why: The program is copied/loaded into main memory (1), but there is no linked development of how or what this leads to, so only one mark is given.

No marks0/2

The CPU fetches the program's instructions from main memory and executes them one at a time.

Why: This describes the fetch-decode-execute cycle, not the operating system loading or allocating memory, which is the Do not accept line; no creditworthy point is made.

3Explain2 marksTopologies Swap Remove

A small office uses a star topology with a central switch.

Explain one benefit of using a star topology in the office.

[2 marks]
Mark scheme

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

  • If one cable/device fails, the other devices on the network are not affected (1) because each device has its own separate connection to the central switch (1)
  • Faults are easier to find (1) because each device has its own cable, so the faulty cable can be checked on its own (1)
  • Data is sent only to the intended device (1) because the central switch forwards the data only to the device it is addressed to (1)
  • Data transfer is fast (1) because each device has its own cable, so devices do not share the cable with each other (1)
  • New devices can be added easily (1) because a device only needs one cable to a spare port on the central switch (1)

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

A benefit stated on its own can earn one mark; the second mark is only for a linked reason.

Accept 'switch' for the central device.

Do not accept 'server' or 'hub' for the central device.

Do not accept 'hub', as a hub sends data to all devices, not only to the intended device.

Do not award a mark for responses that say only that the network is better/more reliable/easier without naming a benefit.

Example answers and how they were marked
Full marks2/2

If one of the cables breaks, the other devices can still communicate because each device has its own separate cable connected to the central switch.

Why: Linked benefit (1) and reason (1): a single cable failure does not affect the other devices because each device has a separate connection to the switch.

Some marks1/2

If one cable breaks, the other devices are not affected.

Why: A benefit is stated on its own (1), but there is no linked reason about each device having its own connection to the central switch, so the second mark is not awarded.

No marks0/2

It is better than a bus topology because every device connects to the central server.

Why: No credit: 'better' does not name a benefit, so no first mark, and 'server' is not accepted as the central device, so there is no linked reason either.

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