Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• A binary digit (1)
• Has the value 0 or 1 (1)
• The smallest unit of data storage (1)
• A single 0 or 1 (1)

Allow binary digit/binary place value for binary digit

Allow a single binary digit for a single 0 or 1

Do not accept a group of 8 bits/half a nibble of 4 bits, which describe a byte or a nibble

Do not accept a binary number/binary on its own

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

• Makes a copy/duplicate of the files/data (1) and stores it on a separate storage device/at a different location (1)
• Copies the data at regular intervals (1) so a recent version is available if the original is lost (1)
• Keeps a copy of the files (1) so that the data can be restored after the original is deleted/corrupted (1)
• Stores the copies on another device (1) so the data is not lost if the original device fails/is damaged by a fire or flood (1)

Do not accept 'it backs up the files' on its own, as this repeats the question.

Do not accept responses about repairing corrupted files or removing malware, as these are different utility programs.

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 one mark for each correct nibble in the correct order:

• 0100 (1)
• 0000 (1)

0 marks if the response is not 8-bit binary.

Indicative content

How the CPU is shared between processes

• The operating system uses multitasking to give each process a short time slice on the CPU, so the music, video editor and download appear to run at the same time.
• The operating system decides which ready process will run next, so one program cannot keep the CPU to itself.
• The operating system can stop a running process and move it back to ready when its time slice ends, so all processes make progress.

The states a process can be in

• When a program is opened, the operating system creates a process and moves its instructions into RAM so it is ready.
• The operating system moves a ready process to running when the CPU is free.
• A running process becomes blocked when it is waiting for input or data, such as the download waiting for data to arrive.
• When the process finishes, the operating system terminates it and releases the resources it was using.

How the operating system responds when a process needs attention

• An interrupt is a signal to the CPU that needs immediate attention, so the operating system suspends the current process and runs the interrupt handler.
• A hardware interrupt could be a printer out of paper, and a software interrupt could be an error in a program.
• After the interrupt has been handled, the operating system can return the interrupted process to the CPU.

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)

Additional guidance

• Level 3 responses must cover at least two of scheduling, process states and interrupts.
• A response that only states that the OS 'manages processes' or gives a program a turn, without expansion, is limited to Level 1.