Edexcel GCSE Computer Science (1CP2) Exam Questions

Award one mark for any of the following up to a maximum of two marks:

• The (same) program/source code can run on different types/makes of computer/processor (1)
• With few/no changes (to the program code) (1)
• The same source code can be translated for each type of processor (1)
• A different compiler/interpreter is used for each type of processor (1)
• The program does not depend on one specific type of processor/hardware (1)
• Only one version of the program needs to be written/kept (1)
• The program is portable between different computers (1)

Allow 'different computers' as meaning different types of computer/processor.

Do not accept a program that will only run on one type of computer / the computer it was written on.

Do not accept written in machine code/binary, is translated into machine code, compiled/interpreted, is a low-level language.

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

• The compiler reports all syntax errors after translation has finished (1) whereas the interpreter stops at the first error it finds (1)
• The interpreter reports a syntax error as soon as it finds one (1) and does not translate/execute any more of the program (1)
• The compiler continues translating after an error (1) and reports the errors at the end (1)
• The interpreter stops translating when it reaches an error (1) but the compiler finishes translating before reporting errors (1)

Do not accept answers about fixing/correcting errors or about object code.

Do not award 'the compiler finds more errors' without saying errors are reported at the end.

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.