Edexcel GCSE Computer Science (1CP2) Exam Questions

• A The next instruction (1)
• The only correct answer is A. The correct answer is the next instruction.
• B is not correct because data is fetched during the execute stage
• C is not correct because an instruction is decoded after it is fetched
• D is not correct because the program counter holds the address used to fetch the instruction

• A Address bus (1)
• The only correct answer is A. The correct answer is address bus. Do not accept 'address' on its own.
• B is not correct because the control bus carries control signals in both directions between the CPU and other components
• C is not correct because the data bus carries data in both directions between the CPU and main memory
• D is not correct because the system bus is the collection of all three buses

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

• (The ECU) is more reliable/less likely to crash (1) because it only runs the one program/has a single purpose (1)
• (The ECU) cannot be affected by other software/viruses (1) because it cannot run other software/it can only run the program it was made for (1)
• (The ECU) is cheaper (1) because it has limited processing resources/less memory/simple components (1)
• (The ECU) uses less power (1) because it has limited processing resources/a simpler processor (1)
• (The ECU) is smaller (1) because it has fewer components/less memory than a general purpose computer (1)

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

A suitable benefit stated on its own earns one mark.

Do not accept a description or a location given as the reason, e.g. 'because it is part of the car', 'because it is inside the engine', 'because it is embedded'.

Do not accept a description of an embedded system on its own as the benefit, e.g. 'it does one specific job' or 'it is part of the car'.

Do not accept 'it is faster'/'it has a more powerful processor' as embedded systems have limited processing resources.

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

• A new program can be loaded/changed without rewiring/reconfiguring the computer (1) because the instructions are held in main memory and can be replaced (by loading a different program) (1)
• Different programs can be run on the same computer (1) because the program instructions are stored in RAM/main memory (1)
• The CPU can fetch instructions automatically (1) so an operator is not needed to enter each instruction by hand (1)
• Instructions can be stored and run in sequence (1) because the CPU reads the next instruction from main memory (1)

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

Allow a benefit stated as an example, e.g. a program can be run as soon as it is loaded (1), with a linked reason (1)

Do not accept a statement that only describes storing or loading, e.g. 'programs can be loaded into memory', without a benefit and a linked reason.

Do not accept 'it is faster' / RAM is quicker to access than secondary storage / RAM is closer to the CPU (1 for nothing): this describes the speed of RAM, not a benefit of storing program instructions in main memory.

Do not accept answers about secondary storage holding programs, e.g. 'the program is kept on the hard drive when the computer is turned off', as this is a property of secondary storage, not of the stored program concept.

Ignore references to the fetch-decode-execute cycle that are not linked to a benefit.