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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 573 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 marksCompression Swap Remove

A video streaming service stores many hours of video.

Describe one reason why the streaming service compresses its video files.

[2 marks]
Mark scheme

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

  • Makes each file smaller (1) so less secondary storage is needed for the videos (1)
  • Uses less bandwidth (1) so the video streams without buffering (1)
  • Reduces the amount of data sent (1) so users use less of their data allowance (1)
  • Can be streamed (1) because the data can be sent as fast as the user watches it (1)

Award one mark for a valid point on its own; the second mark is only awarded when the development is linked to that point.

Do not award a second mark for a development that repeats the point made.

Allow "takes less time to transmit/upload/download" as the development for a smaller file.

Do not accept responses that say compression saves memory/RAM (the videos are stored in secondary storage).

Do not accept compression makes the video more secure or improves its quality.

Example answers and how they were marked
Full marks2/2

It makes each video file smaller (1) so the service needs less storage space for its library (1).

Why: Linked point: smaller file (1) and linked development: less storage needed (1).

Some marks1/2

It reduces the size of the video files.

Why: States that files are made smaller (1); no linked development is given, so the second mark is not awarded (0).

No marks0/2

It encrypts the video so it is safer to send.

Why: Gives security, which the mark scheme does not accept, not a reason for compression; no creditworthy point.

2Explain2 marksUnits & Conversion Swap Remove

A server stores a large amount of data.

The capacity of the server is 16 TiB. Explain one benefit of giving the capacity in tebibytes rather than in bytes.

[2 marks]
Mark scheme

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

  • The capacity is easier to read/write (1) because a tebibyte is 1024^4 bytes so the same capacity in bytes would have many more digits (1)
  • The number is shorter (1) because writing 16 TiB instead of 17 592 186 044 416 bytes uses far fewer digits (1)
  • There is less chance of making a mistake when copying the value (1) because a long byte count of many digits is easy to mistype (1)

For both marks, the expansion must follow/associate with the statement and must refer to the number of digits/length of the value.

Allow 'fewer digits'/'shorter number'/'less chance of error' on its own for the first mark; the second mark needs the linked reason that a tebibyte is 1024^4 bytes, so the value in bytes would be very long/have many more digits.

Do not accept 'it is bigger'/'tebibytes are larger' on its own, as this does not give a benefit of using them.

Do not accept 'easier' on its own without saying what is easier, e.g. fewer digits/shorter number.

Do not accept 'because tebibytes are used for large storage' without a reason about the number of digits/readability.

Example answers and how they were marked
Full marks2/2

It is easier to read because 16 TiB has fewer digits than the same capacity written in bytes, which would be a very long number.

Why: Point that the number is easier to read (1); linked reason that the byte count would have many more digits (1).

Some marks1/2

It uses fewer digits.

Why: States the benefit of fewer digits (1); no linked reason about a tebibyte being 1024^4 bytes so the byte count is very long (0).

No marks0/2

Because a tebibyte is bigger than a byte.

Why: States a fact about the unit, which the mark scheme does not accept on its own; no point about fewer digits or readability, so no mark.

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