Edexcel GCSE Computer Science (1CP2) Exam Questions

• 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 description such as:

• Attempts to repair/rebuild the corrupted file (1) so that it can be opened by its program again (1)
• Recovers/retrieves the parts of the file that can still be read (1) so that the user does not lose all of the data in the file (1)
• Reconstructs the file from data held in other parts of the disk (1) because part of the file/the disk is corrupted (1)
• Saves a new/repaired copy of the file (1) as some of the data in it may not be recoverable (1)

Do not accept 'it repairs the file' on its own, as this repeats the question.

Do not accept responses about restoring a backup/previous version of the file, as this is backup software.

Do not accept responses about scanning for or removing malware.

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

• Each router chooses the best route at the time (1) so when a route becomes busy/congested or fails, later packets are forwarded along a different path (1)
• Routers forward each packet separately (1) so the path a packet takes depends on the traffic conditions when that packet arrives (1)
• A router may send a packet to a different next router (1) if its routing table shows a better/less congested route for that packet (1)
• Traffic on the internet changes (1) so no single path is kept for the file and each packet can use whichever route is best when it is sent (1)

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

Allow reference to a routing table, or to how a router decides the route, as part of the linked reason.

Do not accept 'the packets have different IP addresses' because all packets from the same file have the same destination IP address, even though their routes can differ.

Do not accept 'the internet is busy' or 'there is a lot of traffic' on its own without linking this to the router choosing a different route.

Do not accept 'different routers send the packets' on its own without a reason why a different router/route is chosen.

Do not accept an answer that only says the packets take different routes without explaining why.

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.