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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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4 questions · 7 marks

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1Multiple choice1 markStored Program Computers Swap Remove

Identify the bus that carries addresses in one direction only, from the CPU to main memory.

[1 mark]
  • AAddress bus
  • BControl bus
  • CData bus
  • DSystem bus
Mark scheme
  • A Address bus (1)
  • The only correct answer is A. The correct answer is address bus. Do not accept 'address' on its own.
  • B is not correct because the control bus carries control signals in both directions between the CPU and other components
  • C is not correct because the data bus carries data in both directions between the CPU and main memory
  • D is not correct because the system bus is the collection of all three buses
Example answers and how they were marked
Full marks1/1

A Address bus

Why: Correct option: the address bus carries addresses in one direction only, from the CPU to main memory (1).

No marks0/1

C Data bus

Why: The data bus carries data in both directions, so it is not the bus that carries addresses in one direction only from the CPU to main memory; no creditworthy point.

No marks0/1

B Control bus

Why: The control bus carries control signals in both directions, not addresses in one direction only; this is the common control/address bus confusion, so no mark.

2Short recall2 marksCompression Swap Remove

Files can be compressed before they are stored.

Define the term lossless compression.

[2 marks]
Mark scheme

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

  • Reduces/makes the size of a file smaller (1)
  • No data is lost/removed (during compression) (1)
  • The original file/data can be recreated/restored exactly (1)

Allow 'the compressed file takes up less storage space' for the first mark.

The second and third bullets are two ways of making the same point: award a maximum of one mark for them, so a response that says no data is lost and that the original file can be restored, but does not say the file is smaller, scores one mark.

Do not accept descriptions of lossy compression, e.g. 'it removes data that is not needed to make the file smaller'.

Ignore reference to download/transmission times, bandwidth and streaming, as these are benefits of compression and not part of the definition.

Example answers and how they were marked
Full marks2/2

Lossless compression reduces the size of a file without permanently removing any data, so the original file can be restored exactly.

Why: Reduces the size of a file (1) and no data is lost, so the original can be restored exactly (1); maximum of two marks reached.

Some marks1/2

It makes a file smaller so it downloads more quickly.

Why: Reduces the size of a file (1); the faster download is ignored as a benefit, not part of the definition.

No marks0/2

It removes data that is not needed to make the file smaller.

Why: Describes lossy compression, which the do-not-accept line rules out, so the mention of making the file smaller is not credited.

3Describe2 marksTranslators Swap Remove

High-level code can be translated by a compiler or by an interpreter.

Describe how a compiler translates high-level code differently from an interpreter.

[2 marks]
Mark scheme

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

  • The compiler translates the whole program/complete source code in one go (1) whereas the interpreter translates one line/statement at a time (1)
  • The compiler translates all of the source code before any of it is run/executed (1) but the interpreter translates each line/statement as it reads it (1)
  • The interpreter translates one line/statement at a time (1) and the compiler translates the whole program/source code together (1)

Accept the compiler point and the interpreter point in either order.

Do not accept responses about object code/executable files, when the translated code is executed, how errors are reported, or speed/memory use.

Do not accept 'the interpreter executes/runs each line' on its own, without saying that it translates one line/statement at a time.

Example answers and how they were marked
Full marks2/2

A compiler translates the whole program in one go, while an interpreter translates one line at a time.

Why: Whole program translated in one go (1) and interpreter translates one line at a time (1).

Some marks1/2

A compiler translates the whole program in one go.

Why: Whole program translated in one go (1); no linked point about the interpreter translating a line at a time.

No marks0/2

A compiler produces an executable file, but an interpreter does not.

Why: Describes the output, not the amount translated at a time; object code/executable files are not accepted.

4Explain2 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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