Build a practice paper from 693 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.
3 questions · 5 marks
Computers manipulate binary patterns.
Convert the binary pattern 1010 0100 to denary.
Award one mark for:
164
Why: Correct: 128 + 32 + 4 = 164 (1).
37
Why: Reads the place values from the wrong end (the left-hand bit as 1), so the value is wrong.
3
Why: Counts the 1s instead of adding their place values.
A computer can be used by more than one person.
Describe how an operating system uses access rights to protect each user's files.
Award up to two marks for a linked description such as:
Do not accept responses about asking for a password/username, as this checks who the user is, not what they are allowed to do.
Do not accept 'files are protected/safe' or 'access rights protect files' without saying how access is limited (e.g. read-only access, permissions for different users).
A user can be given read-only access to a file, so they can open it but cannot edit or delete it.
Why: Read-only/read access point (1) and linked development that the user cannot edit/delete the file (1).
A user can be given read-only access to a file.
Why: Read-only/read access point (1); no development saying what this prevents, such as being unable to edit/delete the file (0).
The operating system asks for the password again before the file opens.
Why: Describes asking for a password, which checks who the user is, not access rights to the file; no creditworthy point.
A compiler and an interpreter both translate source code.
Describe one difference between what a compiler produces and what an interpreter produces.
Award up to two marks for a linked description such as:
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.
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).
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.
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.
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