Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• Instructions can manipulate/control the hardware/memory/registers directly (1) so the driver can control the specific device it is written for (1)
• The code is written for one specific processor/architecture (1) so it works with the exact hardware it will control (1)
• The programmer controls exactly how memory/registers are used (1) so the code is efficient and needs little memory, which suits a device that has limited memory (1)
• Each instruction maps to one machine code instruction (1) so the driver code is small enough to fit in the memory of the device (1)

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'.

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

• The programmer can choose the most efficient instructions/registers to use (1) so the program completes its task in fewer steps (1)
• The programmer can optimise the code for the processor (1) because low-level instructions give direct control of registers/memory (1)
• Each low-level instruction maps to one machine code instruction (1) so fewer instructions are executed than for the equivalent high-level code (1)
• The translated code is smaller (1) so fewer instructions are fetched from memory and executed (1)

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

Do not accept 'it is low-level' / 'it is closer to machine code' / 'low-level code is faster' on its own without a reason why it makes the program run faster.

Do not accept 'high-level code has to be translated' / 'high-level code is interpreted' on its own without saying why that makes the program slower.

Do not accept 'the code is smaller' on its own without saying that this means fewer instructions are fetched/executed.

Do not accept 'it is easier to write' or 'quicker to type' as a reason for faster execution.

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

• The compiler translates the whole program into machine code before it is run (1) so no translation is needed while the program is executing (1)
• The machine code/object code is already produced before execution (1) so the CPU can carry out the instructions directly without translating them (1)
• The compiled program does not need an interpreter at run time (1) so no time is spent translating each line before it is executed (1)

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

A statement that translation happens before execution, with no linked reason for faster running, earns 1 mark only.

Do not accept 'faster to run' or 'quicker' on its own without a reason linked to translation before/during execution.

Do not accept 'compiled code is optimised' or 'compilation takes less time' without linking this to translation before execution/at run time.

Do not accept answers about the compiler being installed or available.

The question asks why a compiled program usually runs faster, so answers must refer to when translation happens, not just general performance claims.