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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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3 questions · 6 marks

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1Short recall2 marksStored Program Computers Swap Remove

The central processing unit (CPU) contains an arithmetic logic unit (ALU).

State two types of operation carried out by the ALU.

[2 marks]
Mark scheme

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

  • An arithmetic operation, e.g. addition/subtraction/multiplication/division (1)
  • A logical operation, e.g. comparing two values (is A > B?) / using AND, OR, NOT (1)

Do not accept decoding instructions, fetching instructions or controlling the timing of the CPU, as these are carried out by the control unit.

Example answers and how they were marked
Full marks2/2

It carries out arithmetic operations such as addition and subtraction, and logical operations such as comparing two values to see if one is greater than the other.

Why: Arithmetic operation (1) and logical operation (1).

Some marks1/2

It adds numbers together and works out the result.

Why: Arithmetic operation, addition (1). No logical operation.

No marks0/2

It decodes the instructions that have been fetched from main memory.

Why: Decoding and fetching are the control unit's role; the mark scheme's do-not-accept line covers this.

2Describe2 marksPeripheral Management Swap Remove

A student uses a graphics tablet connected to a computer to draw in a program.

Describe how the operating system passes input from the graphics tablet to the program.

[2 marks]
Mark scheme

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

  • The operating system receives signals/data from the graphics tablet (1) and converts them into data the program can use/process (1)
  • The operating system receives data from the graphics tablet (1) and passes/forwards it to the program being used/the active program (1)
  • The tablet's device driver receives/interprets the signals/data from the tablet (1) so the operating system can pass the input to the program (1)
  • The operating system identifies the graphics tablet as the source of the input (1) so the data is sent to the correct program (1)

Accept 'signals' for 'data' throughout.

Accept reference to the device driver only where it is linked to receiving/interpreting the input (e.g. the driver receives the tablet's signals (1) so the OS can pass data to the program (1)).

Do not accept 'the operating system uses a driver' on its own, without saying what the driver does with the input.

Do not accept generic statements such as 'the operating system runs the tablet' as a description of how input is managed.

Do not accept responses that say the operating system creates/finishes the drawing, or that the tablet stores the input permanently.

Example answers and how they were marked
Full marks2/2

The operating system receives signals from the graphics tablet and passes the data to the program.

Why: Receives signals/data from the tablet (1) and passes the data to the active program (1).

Some marks1/2

The operating system receives signals from the graphics tablet.

Why: Gives the first half of a linked description (1): it receives signals, but does not say what happens to the input.

No marks0/2

The operating system uses a device driver to control the graphics tablet and stores the input.

Why: Only says the OS uses a driver to control the tablet and that input is stored; it does not describe the driver receiving/interpreting the input or the input being passed to the program, so no linked point is credited. The mark scheme rejects 'uses a driver' on its own.

3Describe2 marksTranslators Swap Remove

High-level code can be translated by a compiler or by an interpreter.

Describe how a compiler translates high-level code differently from an interpreter.

[2 marks]
Mark scheme

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

  • The compiler translates the whole program/complete source code in one go (1) whereas the interpreter translates one line/statement at a time (1)
  • The compiler translates all of the source code before any of it is run/executed (1) but the interpreter translates each line/statement as it reads it (1)
  • The interpreter translates one line/statement at a time (1) and the compiler translates the whole program/source code together (1)

Accept the compiler point and the interpreter point in either order.

Do not accept responses about object code/executable files, when the translated code is executed, how errors are reported, or speed/memory use.

Do not accept 'the interpreter executes/runs each line' on its own, without saying that it translates one line/statement at a time.

Example answers and how they were marked
Full marks2/2

A compiler translates the whole program in one go, while an interpreter translates one line at a time.

Why: Whole program translated in one go (1) and interpreter translates one line at a time (1).

Some marks1/2

A compiler translates the whole program in one go.

Why: Whole program translated in one go (1); no linked point about the interpreter translating a line at a time.

No marks0/2

A compiler produces an executable file, but an interpreter does not.

Why: Describes the output, not the amount translated at a time; object code/executable files are not accepted.

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