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 · 4 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 hard disk can become fragmented as files are saved and deleted.
Describe how disk defragmentation software improves the performance of a hard disk.
Award up to two marks for a linked description such as:
Do not accept responses about compressing files, deleting files or increasing the amount of storage, as these are not what defragmentation software does.
Do not accept 'it makes the disk faster' without saying how the files are changed.
It moves the parts of a file so they are stored together in consecutive locations, so the read/write head does not have to move as far and the file opens more quickly.
Why: Linked point (1) and development (1): the file parts are stored together, which reduces read/write head movement.
It reorganises the files on the hard disk so that they are stored together.
Why: The point is made (1) but there is no development saying how this improves performance, so the second mark is not awarded.
It compresses the files so that they take up less space on the disk.
Why: This describes data compression software, which the mark scheme says is not accepted; no creditworthy point is made.
Computer systems manipulate bit patterns.
Convert the hexadecimal number D5 to denary.
Award one mark for:
213
Why: 13 × 16 + 5 = 213 (1).
93
Why: Takes the right-hand digit as the 16s, so the value is wrong.
18
Why: Adds the two digits instead of multiplying the first by 16.
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