Edexcel GCSE Computer Science (1CP2) Exam Questions

• A It can manipulate the hardware directly (1)
• The only correct answer is A. The correct answer is it can manipulate the hardware directly.
• B is not correct because data structures such as arrays and records are a characteristic of high-level languages
• C is not correct because low-level languages are processor/machine dependent, so they are not machine independent
• D is not correct because in a low-level language one instruction translates into one machine code instruction

• A Assembly language (1)
• The only correct answer is A. The correct answer is assembly language.
• B is not correct because C# is a high-level language
• C is not correct because Java is a high-level language
• D is not correct because Python is a high-level language

Award one mark for:

• The whole program (before it is run) (1)

Allow all of the code/the entire program/the whole program in one go

Do not accept one line/statement at a time or each line as it is executed

Do not accept translating only the lines that contain errors

Award one mark for any of the following:

• Object code (1)
• Machine code (1)
• Executable code / an executable (1)

Allow object file.

Do not accept source code.

Do not accept high-level code.

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

• The processor/CPU can only execute machine code/binary instructions (1) so the assembly instructions must be converted into machine code before the program can run (1)
• Each assembly instruction/mnemonic matches/corresponds to one machine code instruction (1) so each line must be replaced with the machine code the processor executes (1)
• The program is written using mnemonics (1) that must be translated into machine code for the processor to carry out the instructions (1)
• The hardware/processor does not understand assembly language directly (1) so it must be translated into machine code that the processor can execute (1)

Do not accept 'assembly language is a low-level language'.

Do not accept 'it is hard to understand' or 'it is not English'.

Do not accept benefits, such as 'machine code runs faster' or 'the program will run more quickly'.

Do not accept 'an assembler/a translator converts it' on its own, with no reference to the processor only being able to execute machine code/binary.

Do not accept responses about high-level languages or about compilers/interpreters.

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 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 same source code can be used on different processors (1) because a compiler/interpreter for each processor translates it into that processor's machine code/instructions (1)
• The program is machine/processor independent (1) because the code is translated into the machine code/instructions of each processor it is run on (1)
• A different compiler/interpreter is used for each type of processor (1) so the same source code can be translated into each processor's machine code/instructions (1)
• The program can be moved/copied to a computer with a different processor (1) because a compiler/interpreter that produces code for that processor exists (1)

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

Do not accept 'it is portable' without a linked reason about translation for different processors.

Do not accept 'it is easier to use/read/write' on its own without a linked reason about translation/processors.

Do not accept 'it is not written in binary'/'it is not machine code'/'it is not written in assembly language' as the reason without saying that the code is translated into each processor's machine code/instructions.

Do not accept the misconception that the program runs directly on any processor without being translated.

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

• The compiler produces object code/machine code for the whole program (1) so there is no complete executable until every line has been translated (1)
• The compiler translates all the source code before producing the object code (1) so the program cannot start until translation has finished (1)
• The compiler checks the whole program for errors during translation (1) so all of the source code must be read before an executable can be produced (1)

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

Allow 'in one go'/'all at once' for the translation point, but this does not earn the second mark unless it is linked to why the program cannot be executed until translation has finished.

A statement that the whole program is translated, with no linked reason about when the program can be executed, earns 1 mark only.

Do not accept 'a compiler is faster' or 'compiled code runs faster' on its own; this does not explain why translation must finish before execution.

Do not accept 'it translates and runs the program one line at a time', as this describes an interpreter.

Indicative content

The output of each type of translator

• A compiler translates the whole program in one go and produces object code.
• The object code is saved as an executable file, which is already in machine code so the processor can run it directly.
• An interpreter does not produce object code, so no translated file exists for the company to save and sell.
• An interpreter translates one line at a time and executes it immediately, but that translation is not kept.

Whether the program has to be translated each time it is run

• Compiled code is translated once, so the executable can be run as many times as the customer likes without being translated again.
• If the source code is edited, the whole program has to be compiled again to produce a new executable.
• An interpreted program is translated again every time it is run, so a customer who runs the program often waits for translation at every run.
• An executable runs faster than interpreted code because it is already in machine code.

What the customer needs on their computer to run the program

• A customer who installs the executable needs no compiler on their computer, so the program will run straight away.
• If the company supplied the source code instead, the customer would need an interpreter installed, and it would have to be an interpreter for their type of computer.
• A customer given only the executable does not have the source code, so cannot change the program.

Conclusion

• A compiler is the better choice for this company, because the executable can be sold and the customer runs it without it being translated again and without being given the source code.
• Using an interpreter would mean supplying the source code to customers and translating the program on every run.

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)

Level 3 responses must cover all three bullets for this company's program, including translating once rather than on every run, and reach a conclusion.

Do not accept 'a compiler fixes errors' (a compiler reports syntax errors at the end of translation, it does not fix them) or 'a compiler is easier to use' with no link to output, translation or the customer. Do not accept answers about translating to assembly language.