Edexcel GCSE Computer Science (1CP2) Exam Questions

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 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 description such as:

• Instructions can manipulate/control the hardware/memory/registers directly (1) so the driver can control the specific device it is written for (1)
• The code is written for one specific processor/architecture (1) so it works with the exact hardware it will control (1)
• The programmer controls exactly how memory/registers are used (1) so the code is efficient and needs little memory, which suits a device that has limited memory (1)
• Each instruction maps to one machine code instruction (1) so the driver code is small enough to fit in the memory of the device (1)

Extra detail, such as naming the device the driver controls, is not needed to earn the marks.

Do not accept 'it is closer to machine code' on its own: it must be developed to show how this helps the driver, e.g. it can control the hardware directly.

Do not accept 'it is faster/quicker' with no link to the hardware/device, e.g. the device responds quickly.

Do not accept 'it is easier to learn', 'it is easier to debug' or 'it takes less time to write'.

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

• Devices (can) understand/interpret the data they receive (1) because they follow the same set of rules for communication (1)
• Data is sent in an agreed format/structure (1) so the receiving device can interpret/understand it correctly (1)
• Devices (can) connect/communicate successfully (1) because they agree how the data is transmitted, such as the type of signal used (1)
• Errors (can) be detected/handled (1) because both devices follow the same rules for checking the data (1)

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

Do not accept 'so devices can talk/communicate with each other' or 'so they can understand each other' without saying they follow the same rules/agreed format.

Do not accept an answer that only states protocols are a set of rules, without saying what this allows (e.g. the data can be understood/interpreted).

Do not accept a faster connection/speed as a reason why protocols are needed.

Do not accept naming a protocol (e.g. TCP/IP, HTTP, Wi-Fi) without an explanation of why it is needed.

Do not accept a description of what a protocol does (e.g. 'TCP splits data into packets') without saying why this is needed.