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.
4 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 store a maximum of 80 bits for a text message. Each character is stored using 7-bit ASCII.
State the maximum number of whole characters that can be stored in the message.
Award one mark for:
Allow 11 remainder 3.
Allow 80 ÷ 7 = 11.428... rounded down to 11.
Do not accept 11.4 or 12 (rounding up or giving a decimal answer).
Do not award an unevaluated calculation such as 80 ÷ 7 with no answer.
11
Why: Correct: 80 ÷ 7 = 11 remainder 3, so 11 whole characters can be stored (1).
11.4
Why: Near miss: gives a decimal result rather than the number of whole characters; the mark scheme does not accept 11.4.
12
Why: Rounds up to 12, but 12 characters would need 84 bits, more than the 80 available; the mark scheme does not accept 12.
A company backs up its files to an external hard drive.
Give one reason why the company compresses the files before backing them up.
Award one mark for any of the following:
Do not accept 'makes the files more secure' or 'encrypts the files'.
The compressed files take up less storage space, so more files can be backed up.
Why: The files take up less storage space (1).
It reduces the amount of disk fragmentation.
Why: Near-miss: compression does not reduce disk fragmentation.
It encrypts the files so they are safer if the drive is stolen.
Why: Misconception: compression does not encrypt files, and security is not accepted.
A device driver is software that allows the operating system to control a piece of hardware. Device drivers are often written in a low-level programming language.
Describe one reason why a low-level programming language is suitable for writing a device driver.
Award up to two marks for a linked description such as:
Extra detail, such as naming the device the driver controls, is not needed to earn the marks.
Do not accept 'it is closer to machine code' on its own: it must be developed to show how this helps the driver, e.g. it can control the hardware directly.
Do not accept 'it is faster/quicker' with no link to the hardware/device, e.g. the device responds quickly.
Do not accept 'it is easier to learn', 'it is easier to debug' or 'it takes less time to write'.
Low-level instructions can manipulate the hardware and memory directly (1) so the driver can control the specific device it was written for, such as a sound card (1).
Why: Point about direct control of hardware/memory (1) linked to controlling the specific device (1). The named device is extra detail and is not needed.
Low-level instructions can manipulate the hardware directly.
Why: Correct point (1) but no linked development saying how this helps the device driver.
It is closer to machine code so it runs faster than a high-level language.
Why: 'Closer to machine code' is not developed into how this helps the driver, and 'runs faster' is not linked to the hardware/device, so no mark.
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