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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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5 questions · 14 marks

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1Multiple choice1 markCharacter Sets Swap Remove

A new character set must be able to represent 70 different characters.

Identify the minimum number of bits needed to represent each character.

[1 mark]
  • A6
  • B7
  • C8
  • D70
Mark scheme
  • B 7 (1)
  • The only correct answer is B. The correct answer is 7.
  • A is not correct because 6 bits give only 64 combinations, which is not enough for 70 characters
  • C is not correct because 7 bits already give 128 combinations, so 8 bits is not the minimum needed
  • D is not correct because 70 is the number of characters needed, not a number of bits
Example answers and how they were marked
Full marks1/1

B 7

Why: The only correct answer: 7 bits give 128 combinations, enough for 70 characters, and it is the smallest number of bits that does (1).

No marks0/1

C 8

Why: Distractor, no credit: a single-tick item has no partial credit, and 8 bits is not the minimum because 7 bits already give 128 combinations, so the scheme's C line gives no mark.

No marks0/1

A 6

Why: Misconception, no credit: 6 bits give only 64 combinations, which cannot represent 70 different characters, so the scheme's A line gives no mark.

2Describe2 marksUtility Software Swap Remove

A student has a large number of photographs stored on a computer.

Describe the purpose of data compression software.

[2 marks]
Mark scheme

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

  • Makes a file/files smaller (1) so less storage space is needed on the disk (1)
  • Reduces the size of the data (1) so it takes less time to upload/download/transfer the file (1)
  • Compresses files/folders into a single file (1) so an attachment is under the size limit for email (1)
  • Reduces the size of the files (1) so more of them fit onto a storage device/backup media (1)

Do not accept 'it compresses the files' on its own, as this repeats the question.

Do not accept responses about protecting files from malware/viruses or about deleting files.

Example answers and how they were marked
Full marks2/2

It makes the files smaller (1) so that they use less storage space on the computer and more of them fit on the disk (1).

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

Some marks1/2

It makes files smaller.

Why: This is the point (1) but there is no development of what the smaller size leads to, so only one mark.

No marks0/2

It protects the files from viruses so that they cannot be damaged.

Why: This describes anti-malware software, which the mark scheme does not accept; no creditworthy point is made.

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.

4Calculate3 marksAdding Binary Numbers Swap Remove

Computers manipulate binary patterns.

(a)

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

[2 marks]
1286432168421
11000001
01100011
Mark scheme

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

  • 0010 (1)
  • 0100 (1)

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

Ignore a carry shown beyond the eighth bit.

Example answers and how they were marked
Full marks2/2

0010 0100

Why: 193 + 99 = 292, which needs 9 bits; the 8 bits that are kept are both correct (2).

Some marks1/2

0010 0101

Why: A slip in the last bit. The first nibble is correct (1); the second is not.

No marks0/2

1110 0011

Why: Never carries. Neither nibble is correct.

(b)

State the name of the error that occurs when this addition is carried out.

[1 mark]
Mark scheme

Award one mark for:

  • overflow (error) (1)
Example answers and how they were marked
Full marks1/1

Overflow

Why: The result needs more bits than are available (1).

No marks0/1

Underflow

Why: A near miss: the result is too big for 8 bits, not too small.

No marks0/1

A syntax error

Why: A syntax error is a mistake in a program's code, not in arithmetic.

5Discuss6 marksUtility Software Swap Remove

A small graphic design company keeps all of its project files on one desktop computer. The computer's hard disk has failed and some files have been lost. The owner has been told to use backup software.

Discuss the backup strategy the company should use.

Your answer should include:

  • the types of backup that could be used
  • where and how often backups should be made
  • how the backups would be used if the hard disk failed again.
[6 marks]
Mark scheme

Indicative content

Types of backup that could be used

  • A full backup copies all of the company's project files every time it is run, so the whole set of files is held together in one backup.
  • A full backup takes longer to make and needs more storage space than an incremental backup.
  • An incremental backup copies only the files that have changed since the previous backup, so it is quicker to run each evening.
  • Restoring from incremental backups needs the last full backup plus every incremental backup made since, which takes longer and is more complex.
  • A weekly full backup with nightly incremental backups can be suitable for the company when the reason is explained using the properties of the two types.

Where and how often backups should be made

  • Backups should be kept on a separate device and, ideally, at a different location, so that a fire or theft in the office cannot destroy the computer and the backups together.
  • Backups should be made regularly, for example every evening, so that at most one day's design work would be lost.
  • Cloud storage can hold copies off-site automatically, without the owner taking a disk home.
  • An external hard disk or USB flash drive can be used as the backup medium, with a copy kept away from the office.

How the backups would be used if the hard disk failed again

  • If the hard disk fails again, the backup software is used to restore the latest full backup and any later incremental backups onto a replacement disk.
  • The restored project files allow the company to carry on working and meet its clients' deadlines.
  • The backups should be tested by restoring a file so that the company knows the backup is usable before it is needed.
  • Backup software does not repair the failed hard disk itself, so a replacement disk is still needed.

Levels

  • Level 0 (0 marks): No rewardable content.
  • Level 1 (1–2 marks): Basic, independent points are made, showing elements of understanding of key concepts/principles of computer science. (AO1) The discussion will contain basic information with little linkage between points made or application to the context. (AO2)
  • Level 2 (3–4 marks): Demonstrates adequate understanding of key concepts/principles of computer science. (AO1) The discussion shows some linkages and lines of reasoning with some structure and application to the context. (AO2)
  • Level 3 (5–6 marks): Demonstrates comprehensive understanding of key concepts/principles of computer science to support the discussion being presented. (AO1) The discussion is well developed, with sustained lines of reasoning that are coherent and logically structured, and which clearly apply to the context. (AO2)

Level 3 requires all three bullets to be developed and applied, including both types of backup (or a justified combination) and a restoration sequence; a response that describes only a full backup cannot reach Level 3.

An answer that explains only one type of backup with at most a brief location or frequency point and no developed restoration is Level 1 (1–2 marks). Credit one off-site point only: cloud storage, an external disk kept elsewhere and 'a different location' are the same point. Do not accept that backup software repairs a failed hard disk or recovers files that were never backed up; an answer that only makes this claim is Level 0. An unsupported weekly-full/nightly-incremental recommendation is not credited.

Example answers and how they were marked
Full marks6/6

The company should make a full backup once a week and incremental backups every evening. A full backup copies every project file, so the whole set is held in one place, but it takes a long time and a lot of space. An incremental backup copies only the files that have changed since the last backup, so it is quick enough to run each night. The backups should be copied to an external hard disk that the owner takes home, or uploaded to cloud storage, so that a fire or a theft cannot destroy the computer and the backups together. Backing up every evening means that at most one day's design work would be lost. If the hard disk fails again, the backup software is used to restore the latest full backup and then each incremental backup onto a new disk, so the company can carry on meeting its clients' deadlines.

Why: Level 3: full and incremental backups are explained and applied to a weekly and nightly schedule (AO1); off-site storage and the restore sequence onto a replacement disk are developed and clearly tied to the hard disk failure (AO2).

Some marks2/6

The company should back up its files to an external hard disk. A full backup copies all of the files, so the project files can be restored if the hard disk fails again. The backup should be kept in a different room in case there is a fire.

Why: Level 1: names a full backup and briefly links it to restoring files, and gives a weak location point, but there is no incremental backup, frequency or developed restore sequence, so the points remain basic and independent.

No marks0/6

Backup software repairs the hard disk when it fails, so the company will not lose anything and can open the files again.

Why: Level 0: the only claim is that backup software repairs the failed hard disk and prevents all loss, which the mark scheme does not accept; no valid type, location, frequency or restoration point is made.

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