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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 · 11 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 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.

3Explain2 marksProtocols & Layers Swap Remove

Two computers exchange data over a network.

Explain why network protocols are needed for the two computers to communicate.

[2 marks]
Mark scheme

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

  • Devices (can) understand/interpret the data they receive (1) because they follow the same set of rules for communication (1)
  • Data is sent in an agreed format/structure (1) so the receiving device can interpret/understand it correctly (1)
  • Devices (can) connect/communicate successfully (1) because they agree how the data is transmitted, such as the type of signal used (1)
  • Errors (can) be detected/handled (1) because both devices follow the same rules for checking the data (1)

For both marks, the expansion must follow/associate with the statement.

Do not accept 'so devices can talk/communicate with each other' or 'so they can understand each other' without saying they follow the same rules/agreed format.

Do not accept an answer that only states protocols are a set of rules, without saying what this allows (e.g. the data can be understood/interpreted).

Do not accept a faster connection/speed as a reason why protocols are needed.

Do not accept naming a protocol (e.g. TCP/IP, HTTP, Wi-Fi) without an explanation of why it is needed.

Do not accept a description of what a protocol does (e.g. 'TCP splits data into packets') without saying why this is needed.

Example answers and how they were marked
Full marks2/2

Devices can understand the data they receive (1) because they follow the same set of rules for communication (1).

Why: Linked point (1) and reason (1): following the same rules is what lets the devices understand the data.

Some marks1/2

Data is sent in an agreed format (1).

Why: Point (1) identified, but no linked reason saying what the agreed format achieves.

No marks0/2

Protocols are needed so the connection is faster (0) because more data can be sent at once.

Why: Speed is not a reason protocols are needed, so there is no creditworthy point or linked reason.

4Discuss6 marksTranslators Swap Remove

A company writes a photo editing program in a high-level language. The company will sell the finished program to customers. Each customer will install the program on their own computer and run it many times.

Discuss whether the company should use a compiler or an interpreter to translate the program before it is sold.

Your answer should include:

  • the output of each type of translator
  • whether the program has to be translated each time it is run
  • what the customer needs on their computer to run the program.
[6 marks]
Mark scheme

Indicative content

The output of each type of translator

  • A compiler translates the whole program in one go and produces object code.
  • The object code is saved as an executable file, which is already in machine code so the processor can run it directly.
  • An interpreter does not produce object code, so no translated file exists for the company to save and sell.
  • An interpreter translates one line at a time and executes it immediately, but that translation is not kept.

Whether the program has to be translated each time it is run

  • Compiled code is translated once, so the executable can be run as many times as the customer likes without being translated again.
  • If the source code is edited, the whole program has to be compiled again to produce a new executable.
  • An interpreted program is translated again every time it is run, so a customer who runs the program often waits for translation at every run.
  • An executable runs faster than interpreted code because it is already in machine code.

What the customer needs on their computer to run the program

  • A customer who installs the executable needs no compiler on their computer, so the program will run straight away.
  • If the company supplied the source code instead, the customer would need an interpreter installed, and it would have to be an interpreter for their type of computer.
  • A customer given only the executable does not have the source code, so cannot change the program.

Conclusion

  • A compiler is the better choice for this company, because the executable can be sold and the customer runs it without it being translated again and without being given the source code.
  • Using an interpreter would mean supplying the source code to customers and translating the program on every run.

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 responses must cover all three bullets for this company's program, including translating once rather than on every run, and reach a conclusion.

Do not accept 'a compiler fixes errors' (a compiler reports syntax errors at the end of translation, it does not fix them) or 'a compiler is easier to use' with no link to output, translation or the customer. Do not accept answers about translating to assembly language.

Example answers and how they were marked
Full marks6/6

The company should use a compiler. A compiler translates the whole program in one go and produces object code, which is saved as an executable file. This executable is already in machine code, so the customer's processor can run it directly. The program is translated only once, so a customer who runs the program many times does not wait for it to be translated again, and it runs faster than interpreted code would. An interpreter produces no object code, so the company would have nothing to sell as an executable. The customer would have to be given the source code and would need an interpreter installed on their computer, and the program would be translated again every time it was run.

Why: Level 3. Covers the output of both translators (executable from the compiler, no object code from the interpreter), the effect of translating once rather than on every run, and what the customer needs on their computer, all applied to the company selling the program, with a clear conclusion.

Some marks3/6

A compiler produces an executable file, which the company can save and sell to its customers. An interpreter does not produce an executable file, so the customer would need the source code and an interpreter installed on their computer to run the program. This means a compiler is better for the company, because customers can just run the file they are given.

Why: Level 2. Gives the output of both translators and links this to what the customer needs, with a conclusion, but never says the compiled program is translated once while an interpreted one is translated on every run, so the reasoning is not developed enough for Level 3.

No marks0/6

The company should use a compiler because it is easier to write programs with a compiler and it fixes the errors in the program before the customers get it.

Why: Level 0. No creditworthy point: 'easier to write programs' is not linked to the output, the translation each run or the customer, and 'fixes the errors' is a misconception, as the mark scheme's guidance says a compiler only reports errors at the end of translation.

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