Menu

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.

Build a paper

Topics (none ticked: all of them)
Question types (none ticked: all of them)

Practice paper

3 questions · 7 marks

Pick again
Print
1Describe2 marksMemory Management Swap Remove

The operating system is held in main memory while the computer is running.

Describe how the operating system stops a running program from overwriting memory that is not its own.

[2 marks]
Mark scheme

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

  • It keeps a record of which memory addresses/areas belong to each program and to the operating system (1) so it knows which addresses a program is allowed to use (1)
  • Each program is given its own area of main memory (1) so a program cannot write to the addresses used by another program or by the operating system (1)
  • The memory used by the operating system is marked as protected/reserved (1) so a program that tries to write to it is blocked/causes an error (1)
  • The address a program writes to is checked against the record of its allocated area (1) and the write is stopped if the address is outside that area (1)

Allow the memory being protected to be that of the operating system or of another program.

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

Do not award generic answers such as 'the operating system manages memory' or 'the operating system keeps track of memory'.

Do not award responses about stopping programs using too much memory or allocating memory, as these are not about protecting memory being overwritten.

Do not award responses about virtual memory, paging or moving processes to secondary storage.

Do not award responses about firewalls, antivirus software or passwords.

Example answers and how they were marked
Full marks2/2

The operating system gives each program its own area of main memory so that a program cannot write to the addresses used by another program or by the operating system.

Why: Each program is given its own area of main memory (1) linked to it not being able to write to the addresses used by another program or the operating system (1).

Some marks1/2

The operating system gives each program its own area of main memory.

Why: Each program is given its own area of main memory (1), but there is no linked development saying how this stops a program overwriting memory that is not its own.

No marks0/2

The operating system stops a program overwriting memory by moving it into virtual memory when it uses too much.

Why: This describes virtual memory and limiting how much memory a program uses, not protecting memory from being overwritten, so neither bullet applies and the Do not award lines rule it out.

2Describe2 marksTranslators Swap Remove

A compiler and an interpreter both translate source code.

Describe one difference between what a compiler produces and what an interpreter produces.

[2 marks]
Mark scheme

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

  • A compiler produces object code/machine code/an executable (file) (1) whereas an interpreter produces no object code/translated file (1)
  • A compiler produces a machine code file (1) that can be run on its own/without the compiler/translator being present (1)
  • An interpreter produces no object code/file (1) because it translates and executes each line instead of saving translated code (1)
  • The compiler's output can be saved/stored (1) and run again later, while interpreted code has to be translated again each time it is run (1)

Allow binary for machine code.

Allow executable/an executable for object code.

Do not accept responses about translating the whole program, reporting errors or the speed of execution.

Do not accept 'the interpreter translates/executes one line at a time' on its own: this is how it translates, not what it produces. It earns the development only when linked to no object code/translated file being produced.

Do not accept the interpreter producing object code/an executable.

Example answers and how they were marked
Full marks2/2

A compiler produces object code, which is saved as a file, whereas an interpreter does not produce a file because it translates and executes each line.

Why: Compiler produces object code (1) contrasted with the interpreter producing no object code/translated file (1).

Some marks1/2

The compiler produces machine code.

Why: Machine code/object code produced (1); there is no contrast with the interpreter, so the development is not earned.

No marks0/2

The interpreter produces object code for each line it translates.

Why: Reverses the translators' outputs: the interpreter produces no object code, so nothing is creditworthy.

3Calculate3 marksAdding Binary Numbers Swap Remove

Binary patterns can represent numbers.

(a)

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

[2 marks]
1286432168421
11011011
11011100
Mark scheme

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

  • 1011 (1)
  • 0111 (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

1011 0111

Why: 219 + 220 = 439, which needs 9 bits; the 8 bits that are kept are both correct (2).

Some marks1/2

0000 0111

Why: Forgets to carry the 1s. The second nibble is correct (1); the first is not.

No marks0/2

1101 1111

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.

Questions by topic

More ways to revise Edexcel GCSE Computer Science (1CP2)

Teachers: build a paper, print it with the mark schemes at the end, and sign your school up to set your classes activities on every topic.

Fetch Decode Explain isn't affiliated with or endorsed by Pearson Edexcel.