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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 markCharacter Sets Swap Remove

Characters are encoded using 7-bit ASCII.

Identify the number of different characters that can be represented using 7-bit ASCII.

[1 mark]
  • A64
  • B127
  • C128
  • D256
Mark scheme
  • C 128 (1)
  • The only correct answer is C. The correct answer is 128.
  • A is not correct because 6 bits give only 64 different combinations
  • B is not correct because 127 is the largest 7-bit value, not the number of characters that 7 bits can represent
  • D is not correct because 256 characters need 8 bits, as used by 8-bit extended ASCII
Example answers and how they were marked
Full marks1/1

C 128

Why: Selects the only correct option (1): 7 bits give 2 to the power of 7, which is 128 different characters.

No marks0/1

D 256

Why: Near miss scoring 0: 256 is the number of characters that 8 bits give in extended ASCII, not 7-bit ASCII.

No marks0/1

B 127

Why: Misconception scoring 0, the off-by-one error the examiners' report describes: 127 is the largest 7-bit value, but 7 bits give 128 different characters.

2Describe2 marksUtility Software Swap Remove

A computer can lose power while a file is being saved.

Describe what file repair software does.

[2 marks]
Mark scheme

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

  • Attempts to repair/rebuild the corrupted file (1) so that it can be opened by its program again (1)
  • Recovers/retrieves the parts of the file that can still be read (1) so that the user does not lose all of the data in the file (1)
  • Reconstructs the file from data held in other parts of the disk (1) because part of the file/the disk is corrupted (1)
  • Saves a new/repaired copy of the file (1) as some of the data in it may not be recoverable (1)

Do not accept 'it repairs the file' on its own, as this repeats the question.

Do not accept responses about restoring a backup/previous version of the file, as this is backup software.

Do not accept responses about scanning for or removing malware.

Example answers and how they were marked
Full marks2/2

It recovers the parts of the file that can still be read (1) so that the user does not lose everything that was saved in it (1).

Why: The point (1) and a linked development giving the effect (1).

Some marks1/2

It rebuilds the damaged file from other parts of the disk.

Why: A valid point is made (1) but there is no development of what this achieves, so the second mark is not awarded.

No marks0/2

It restores the last backup of the file so the user gets the data back.

Why: This describes backup software, which the mark scheme does not accept for this question.

3Describe2 marksLow and High Level Languages Swap Remove

A programmer has written a program in assembly language.

Describe why it is necessary to translate the program into machine code before it can be run.

[2 marks]
Mark scheme

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

  • The processor/CPU can only execute machine code/binary instructions (1) so the assembly instructions must be converted into machine code before the program can run (1)
  • Each assembly instruction/mnemonic matches/corresponds to one machine code instruction (1) so each line must be replaced with the machine code the processor executes (1)
  • The program is written using mnemonics (1) that must be translated into machine code for the processor to carry out the instructions (1)
  • The hardware/processor does not understand assembly language directly (1) so it must be translated into machine code that the processor can execute (1)

Do not accept 'assembly language is a low-level language'.

Do not accept 'it is hard to understand' or 'it is not English'.

Do not accept benefits, such as 'machine code runs faster' or 'the program will run more quickly'.

Do not accept 'an assembler/a translator converts it' on its own, with no reference to the processor only being able to execute machine code/binary.

Do not accept responses about high-level languages or about compilers/interpreters.

Example answers and how they were marked
Full marks2/2

The processor can only execute machine code, so the assembly instructions must be converted into machine code before the program can run.

Why: States what the processor can execute (1) and links it to converting the program's instructions into machine code (1).

Some marks1/2

Each assembly instruction matches one machine code instruction.

Why: Correct point about the one-to-one match (1) but no development saying that this is because the processor only executes machine code.

No marks0/2

Because an assembler translates assembly language into machine code.

Why: Names the translator but gives no reason tied to the processor only being able to execute machine code, so no mark; this is in the 'Do not accept' guidance.

4Calculate2 marksAdding Binary Numbers Swap Remove

Computer systems manipulate bit patterns.

Complete the table to show the result of the 8-bit binary addition.

[2 marks]
1286432168421
10111000
00011111
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 1101 (1)
  • 0111 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

1101 0111

Why: 184 + 31 = 215, carrying where a column adds to 2: both nibbles are correct (2).

Some marks1/2

1010 0111

Why: Writes 0 for 1 + 1 but forgets to carry the 1. The second nibble is correct (1); the first is not.

No marks0/2

1011 1111

Why: Writes 1 in every column with a 1 and never carries. Neither nibble is correct.

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