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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 631 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 markTranslators Swap Remove

Identify the type of translator that translates the whole program into machine code before it is run.

[1 mark]
  • AAssembler
  • BCompiler
  • CInterpreter
  • DLinker
Mark scheme
  • B Compiler (1)
  • The only correct answer is B. The correct answer is compiler.
  • A is not correct because an assembler translates assembly language code into machine code, not a high-level program
  • C is not correct because an interpreter translates and executes the code line by line, without producing a complete machine code program first
  • D is not correct because a linker combines object code files into a single executable, it does not translate source code
Example answers and how they were marked
Full marks1/1

B Compiler

Why: Selected the compiler, the translator that translates the whole program into machine code before it is run (1).

No marks0/1

C Interpreter

Why: Near miss: an interpreter translates and executes the code line by line, so it does not translate the whole program into machine code before it is run.

No marks0/1

A Assembler

Why: Confuses the translators: an assembler translates assembly language code into machine code, it does not translate a high-level program as a whole.

2Short recall2 marksLow and High Level Languages Swap Remove

Device drivers allow hardware devices to work with a computer system.

Give two advantages of using a low-level programming language to write device drivers.

[2 marks]
Mark scheme

Award one mark for any of the following up to a maximum of two marks:

  • It can control/manipulate the hardware (components/registers/memory locations) directly (1)
  • Each instruction maps to a single machine-code instruction, so the behaviour/timing can be controlled precisely (1)
  • The code can run very quickly / has a fast execution time (1)
  • The code uses less memory/RAM (1)
  • The code can be optimised for a particular processor/chipset (1)

Only award one mark where both 'controls the hardware' and 'accesses registers/memory locations' are given, as these are the same point.

Do not accept 'it is closer to the hardware' without saying that it controls or accesses the hardware directly.

Do not accept easier/faster to write/program/learn/understand/debug (these are advantages of high-level languages).

Do not accept faster/quicker without qualification.

Do not accept portable/machine independent.

Do not accept does not need to be translated/compiled (assembly language must be assembled).

Do not accept it is a low-level language / a repeat of the question.

Example answers and how they were marked
Full marks2/2

It can control the hardware directly and the code runs very quickly.

Why: Two creditworthy advantages: controls the hardware directly (1); fast execution (1).

Some marks1/2

It uses less memory than a high-level language.

Why: Creditworthy point: uses less memory/RAM (1). Only one advantage given.

No marks0/2

It is easier to understand and debug than a high-level language.

Why: These are advantages of high-level languages, not low-level ones; the mark scheme does not accept easier to understand or debug.

3Describe2 marksTranslators Swap Remove

Source code can contain syntax errors.

Describe how a compiler and an interpreter differ in the way they deal with syntax errors.

[2 marks]
Mark scheme

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

  • The compiler reports all syntax errors after translation has finished (1) whereas the interpreter stops at the first error it finds (1)
  • The interpreter reports a syntax error as soon as it finds one (1) and does not translate/execute any more of the program (1)
  • The compiler continues translating after an error (1) and reports the errors at the end (1)
  • The interpreter stops translating when it reaches an error (1) but the compiler finishes translating before reporting errors (1)

Do not accept answers about fixing/correcting errors or about object code.

Do not award 'the compiler finds more errors' without saying errors are reported at the end.

Example answers and how they were marked
Full marks2/2

A compiler reports all the syntax errors at the end of translation, whereas an interpreter stops and reports the error as soon as it finds one.

Why: Compiler reports errors at the end (1) and interpreter stops/reports at the first error (1).

Some marks1/2

An interpreter stops translating when it finds a syntax error.

Why: Interpreter stops at the first error (1); no comparison with when the compiler reports errors.

No marks0/2

A compiler reports a syntax error immediately, before translating the rest of the program.

Why: Reverses the compiler's behaviour; it finishes translating before reporting errors.

4Explain2 marksTranslators Swap Remove

A programmer writes a program in a high-level language. The program is translated by a compiler.

Explain why a compiler must translate the whole program before any of it can be executed.

[2 marks]
Mark scheme

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

  • The compiler produces object code/machine code for the whole program (1) so there is no complete executable until every line has been translated (1)
  • The compiler translates all the source code before producing the object code (1) so the program cannot start until translation has finished (1)
  • The compiler checks the whole program for errors during translation (1) so all of the source code must be read before an executable can be produced (1)

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

Allow 'in one go'/'all at once' for the translation point, but this does not earn the second mark unless it is linked to why the program cannot be executed until translation has finished.

A statement that the whole program is translated, with no linked reason about when the program can be executed, earns 1 mark only.

Do not accept 'a compiler is faster' or 'compiled code runs faster' on its own; this does not explain why translation must finish before execution.

Do not accept 'it translates and runs the program one line at a time', as this describes an interpreter.

Example answers and how they were marked
Full marks2/2

A compiler produces object code for the whole program, so there is no complete executable until every line has been translated.

Why: Object code for the whole program (1) linked to there being no complete executable until every line is translated (1).

Some marks1/2

A compiler translates the whole program in one go.

Why: Translation of the whole program only (1); no linked reason about when the program can be executed, so the second mark is not awarded.

No marks0/2

A compiler translates and runs the program one line at a time, so it stops when it finds an error.

Why: Confuses a compiler with an interpreter; nothing about translating the whole program before execution, so no creditworthy point.

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