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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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3 questions · 4 marks

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1Short recall1 markCompression Swap Remove

A company backs up its files to an external hard drive.

Give one reason why the company compresses the files before backing them up.

[1 mark]
Mark scheme

Award one mark for any of the following:

  • More files/data can be stored (in the same storage space) (1)
  • The files take up less storage space (1)
  • The backup is quicker/faster to complete (1)
  • Less data needs to be transferred to the backup device (1)

Do not accept 'makes the files more secure' or 'encrypts the files'.

Example answers and how they were marked
Full marks1/1

The compressed files take up less storage space, so more files can be backed up.

Why: The files take up less storage space (1).

No marks0/1

It reduces the amount of disk fragmentation.

Why: Near-miss: compression does not reduce disk fragmentation.

No marks0/1

It encrypts the files so they are safer if the drive is stolen.

Why: Misconception: compression does not encrypt files, and security is not accepted.

2Short recall1 markUnits & Conversion Swap Remove

A file has a size of 2 kibibytes.

State the number of bytes in the file.

[1 mark]
Mark scheme

Award one mark for:

  • 2048 (1)
  • 2 × 1024 (1)
  • 2^11 (1)

Allow 2048 bytes.

Do not accept 2000, which is the number of bytes in two decimal kilobytes.

Do not accept 1024, which is the number of bytes in one kibibyte.

Do not accept 16, which is the number of bits in two bytes.

Example answers and how they were marked
Full marks1/1

2048

Why: 2048 is 2 × 1024, the number of bytes in 2 kibibytes (1).

No marks0/1

2000

Why: 2000 uses the decimal kilobyte, not the binary kibibyte; the mark scheme does not accept it.

No marks0/1

16

Why: 16 is the number of bits in two bytes, confusing bits with bytes; the mark scheme does not accept it.

3Describe2 marksCompression Swap Remove

A school compresses its text documents before backing them up.

Describe how lossless compression reduces the size of a text file.

[2 marks]
Mark scheme

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

  • Repeated words/patterns are found (1) and stored once in a dictionary with a code (1)
  • Each repeated word/pattern is replaced by a shorter code (1) so fewer bits are needed to store the text (1)
  • No data is removed (1) so the original text can be recreated exactly (1)
  • The compressed file is smaller (1) but all the original characters can still be restored (1)

Do not accept answers that say data is permanently removed or quality is reduced.

Example answers and how they were marked
Full marks2/2

It finds repeated words in the document and stores them once in a dictionary with a code.

Why: Linked point: repeated words found (1) and development: stored once in a dictionary (1).

Some marks1/2

It makes the file smaller without losing any of the data.

Why: States that no data is lost (1); no linked method or exact restoration is given (1).

No marks0/2

It removes repeated characters permanently so the file takes up less space.

Why: Describes permanent removal, which is lossy, not lossless; no credit.

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