Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• Decodes the instruction / works out what the instruction is (1)
• Sends control signals to the other components (of the CPU) (1)
• Coordinates/controls the activities of the CPU (1)
• Directs the timing of the other components / controls when each component acts (1)

Do not accept carrying out arithmetic or logical operations, as this is the role of the ALU.

Do not accept holding/storing the data or instructions, as this is the role of the registers/main memory.

Award one mark for each of:

• 5 × 1024^3 / 5 × 1024 × 1024 × 1024 / 5 × 2^30, for the number of bytes (1)
• A fully correct expression with × 8 to convert bytes to bits, in any order, e.g. 5 × 1024^3 × 8, 8 × 5 × 2^30 (1)

Accept 5 × 1 073 741 824 × 8.

Accept 5 × 2^33 or 42 949 672 960 as a fully correct expression (2 marks).

Do not accept 5 × 1000^3 × 8, which uses decimal multiples.

Do not accept ÷ 8, which converts bits to bytes.

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

• The interpreter executes each line as soon as it has been translated (1) so translation and execution happen together/at the same time (1)
• The compiler translates the whole program first (1) and the machine code is run later/separately (1)
• The interpreter translates the code and runs it while the program is running (1) whereas the compiler does not run the code it produces (1)
• The compiler produces translated code that is executed only after all the translation has finished (1) but the interpreter executes each line immediately (1)

Allow 'translates one line at a time' where it is linked to executing each line immediately.

Do not accept answers that only state that a compiler is faster/an interpreter is slower, without reference to when execution happens.

Do not accept answers that only give object code, error reporting or portability, without reference to when execution happens.

Do not accept the compiler executing the program as it translates it.