Edexcel GCSE Computer Science (1CP2) Exam Questions

• A They are lost (1)
• The only correct answer is A. The correct answer is They are lost
• B is not correct because RAM is volatile and its contents are lost when the power is switched off, so they are not stored permanently
• C is not correct because RAM is volatile and its contents are lost when the power is switched off, so they are not saved to secondary storage
• D is not correct because ROM is read-only memory that holds the start-up instructions, so the contents of RAM are not written to it

• A Decodes instructions (1)
• The only correct answer is A. The correct answer is Decodes instructions.
• B is not correct because the arithmetic logic unit performs arithmetic operations
• C is not correct because main memory stores data and instructions
• D is not correct because registers temporarily store data being processed

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

• It is a computer/processor built into a larger device (1) to carry out a single dedicated task/function (1)
• It is a combination of a processor, memory and input/output in one unit (1) that controls the device it is part of (1)
• It is a computer that forms part of another device (1) so it is not used as a general purpose computer (1)

Allow 'forms part of another device' or 'inside another device' for the first mark.

Do not award the second mark for a separate fact that is not linked to the first point, e.g. 'It is built into a device and it uses little power' would earn only the first mark (1).

Do not accept 'a small computer' on its own, with no reference to being part of another device or performing a dedicated task.

Do not accept 'a computer that controls a device' on its own, with no reference to it being built into/part of a larger device or carrying out a dedicated task.

Do not accept 'it performs a single dedicated task' on its own, with no reference to it being built into/part of a larger device.

Do not accept descriptions of a general purpose computer, e.g. 'it can run many different programs' or 'new software can be installed'.

Do not accept 'it is a system that is embedded in another system' as this repeats the term in the question.

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:

• (The ECU) is more reliable/less likely to crash (1) because it only runs the one program/has a single purpose (1)
• (The ECU) cannot be affected by other software/viruses (1) because it cannot run other software/it can only run the program it was made for (1)
• (The ECU) is cheaper (1) because it has limited processing resources/less memory/simple components (1)
• (The ECU) uses less power (1) because it has limited processing resources/a simpler processor (1)
• (The ECU) is smaller (1) because it has fewer components/less memory than a general purpose computer (1)

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

A suitable benefit stated on its own earns one mark.

Do not accept a description or a location given as the reason, e.g. 'because it is part of the car', 'because it is inside the engine', 'because it is embedded'.

Do not accept a description of an embedded system on its own as the benefit, e.g. 'it does one specific job' or 'it is part of the car'.

Do not accept 'it is faster'/'it has a more powerful processor' as embedded systems have limited processing resources.