Edexcel GCSE Computer Science (1CP2) Exam Questions

• B Compiler (1)
• The only correct answer is B. The correct answer is compiler.
• A is not correct because an assembler translates assembly language code into machine code, not a high-level program
• C is not correct because an interpreter translates and executes the code line by line, without producing a complete machine code program first
• D is not correct because a linker combines object code files into a single executable, it does not translate source code

Award one mark for:

• Several/multiple machine code instructions (1)

The answer must refer to instructions.

Do not accept machine code on its own.

Do not accept binary on its own.

Do not accept 'one or more machine code instructions' as it does not show that one statement becomes several instructions.

Do not accept assembly code/compiled code/low-level code on their own.

Do not accept 'a line of code'/'a statement' as this repeats the question.

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

• Translates/converts (high-level/source) code one line/statement at a time (1)
• Translates/converts the code and executes/runs each line as it goes (1)
• Executes/runs each line/statement immediately after it is translated (1)
• Reports/stops with an error message as soon as a syntax error is found (1)

Allow 'runs' for executes, 'converts' for translates and 'instruction' for line/statement

Do not accept translates the whole program before it is run

Do not accept produces/creates object code, an executable file or machine code that is saved

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

• A compiler produces object code/machine code/an executable (file) (1) whereas an interpreter produces no object code/translated file (1)
• A compiler produces a machine code file (1) that can be run on its own/without the compiler/translator being present (1)
• An interpreter produces no object code/file (1) because it translates and executes each line instead of saving translated code (1)
• The compiler's output can be saved/stored (1) and run again later, while interpreted code has to be translated again each time it is run (1)

Allow binary for machine code.

Allow executable/an executable for object code.

Do not accept responses about translating the whole program, reporting errors or the speed of execution.

Do not accept 'the interpreter translates/executes one line at a time' on its own: this is how it translates, not what it produces. It earns the development only when linked to no object code/translated file being produced.

Do not accept the interpreter producing object code/an executable.

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

• Statements are written in English-like words/use maths symbols (1) so the programmer can understand more easily what each one does (1)
• The language uses meaningful names for variables/structured constructs such as loops (1) so the code is easier to read/follow (1)
• One statement translates into several machine code instructions (1) so there are fewer instructions to learn/understand for the same task (1)

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

Do not accept 'it is easier' / 'it is simpler' on its own, without saying what is easier/simpler.

Do not accept 'the computer understands it directly' / 'it does not need translating'.

Do not award answers about the program running faster or using less memory, as these are not about ease of learning.

Indicative content

Machine independence

• A high-level language is machine independent, so the same source code can be run on different types of computer with few or no changes.
• The company can write the program once and sell it to users with different computers, without rewriting the code for each type of computer.
• Only one version of the program needs to be written and maintained, so development takes the company less time.

Processor specificity

• A low-level language is processor-specific, so a program written for one processor will not run on a different processor without being rewritten.
• Assembly language instructions depend on the instruction set of the particular processor, so the company would need a separate version of the program for each type of computer.
• Writing a separate low-level version for every type of computer would take the company much longer than writing one high-level program.
• Low-level code gives direct control of the hardware of one processor, so it is better suited to device drivers than to a program that must run on many different computers.

Translation

• High-level source code is translated for each type of computer by a compiler or an interpreter, so one version of the source code is enough for all the users.
• Assembly language is translated into machine code by an assembler, and the assembler produces machine code for one specific processor only.
• Machine code is already in a form that one particular processor can execute directly, but the same machine code will not run on a different processor.
• Each high-level statement translates into several machine code instructions, so the programmer does not need to know the instruction set of the processor.

Levels

• Level 0 (0 marks): No rewardable content.
• Level 1 (1–2 marks): Basic, independent points are made, showing elements of understanding of key concepts/principles of computer science. (AO1) The discussion will contain basic information with little linkage between points made or application to the context. (AO2)
• Level 2 (3–4 marks): Demonstrates adequate understanding of key concepts/principles of computer science. (AO1) The discussion shows some linkages and lines of reasoning with some structure and application to the context. (AO2)
• Level 3 (5–6 marks): Demonstrates comprehensive understanding of key concepts/principles of computer science to support the discussion being presented. (AO1) The discussion is well developed, with sustained lines of reasoning that are coherent and logically structured, and which clearly apply to the context. (AO2)

Additional guidance

• Level 3 responses must cover both high-level machine independence and low-level processor specificity, with the effect on the company's decision.
• Do not award low-level language, assembly language or machine code as portable, or 'high-level languages are written in English/like English' as a reason for machine independence.