Edexcel GCSE Computer Science (1CP2) Exam Questions

• B RAM is faster to access than secondary storage (1)
• The only correct answer is B. The correct answer is RAM is faster to access than secondary storage.
• A is not correct because RAM is volatile
• C is not correct because RAM has a smaller capacity than secondary storage
• D is not correct because RAM is more expensive than secondary storage

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

• A read/write head moves over the surface of the disk (1) to read/write data by detecting or changing the magnetic alignment of areas of the surface (1)
• The head magnetises areas of the disk surface in different directions (1) so each area represents a binary 1 or 0 (1)
• Data is stored on concentric circles called tracks (1) which are divided into sectors (1)

Allow one mark for tracks/concentric circles on their own.

For the second mark in the first two bullets, the response must refer to the magnetic alignment/charge being detected or changed, not just that the head reads/writes data.

Do not award a mark for 'it is magnetic' or 'it stores data in binary' with no description of how the data is stored.

Do not accept descriptions of optical storage (e.g. a laser, pits and lands) or solid state storage (e.g. electric charges in chips).

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

• Decodes each (fetched) instruction (1) to work out which operation is needed / which components should carry it out (1)
• Coordinates/directs the other components (1) by sending control signals along the control bus (1)
• Fetches the next instruction (1) by sending its address to main memory along the address bus (1)
• Sends a read/write control signal to main memory (1) so that the instruction or data is transferred during the fetch/execute stage (1)

Do not accept answers about synchronising the CPU or timing the cycles (that is the role of the clock).

Do not accept answers about carrying out arithmetic or logical operations (that is the ALU).

Do not accept answers about holding data or the results of instructions (that is registers/main memory).

Do not accept generic answers that only say the CU controls the CPU or processes instructions, with no linked development.

Only award one mark for a response that only repeats that the CU sends control signals; the second mark needs a linked outcome such as coordination, a memory read/write, or fetching an instruction.

Do not accept 'during the decode stage' as the development for the decoding point, as it restates the question.

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

• A temperature sensor measures/reads the temperature in the greenhouse (1) which the processor compares with the value stored in the system (1)
• The heater is switched on (1) when the temperature reading goes below the value stored in the system (1)
• A fan/vent/window is opened/a cooler is switched on (1) when the temperature reading goes above the value stored in the system (1)
• The temperature is checked/measured continuously (1) so the heater/fan is switched on or off as soon as the temperature changes (1)

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

Allow one mark for a correct point on its own without a linked reason, e.g. 'a temperature sensor measures the temperature'.

Do not award 'the embedded system controls/keeps the temperature correct' as this repeats the question.

Do not accept naming a device without saying what it does, e.g. 'the greenhouse has a thermostat'.