Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• The start and end address/size of the block allocated to each program is recorded (1) so the operating system knows which areas of main memory are in use and which are free (1)
• The record is checked before memory is allocated (1) so memory already in use is not given to another program/is not overwritten (1)
• The record is searched for a free block that is large enough (1) so a newly loaded program is placed in a suitable area of main memory (1)
• The record is updated when a program ends/closes (1) so the memory it was using is marked as free for other programs (1)

Allow the record to be called a memory map/memory table/allocation table.

A response that only says the operating system keeps a record/list of the memory each program is using, without saying what the record contains, earns 0 marks.

A response that states what the record contains, e.g. the addresses/the start and end address of each block, earns 1 mark even if it does not say how the record is used.

Do not accept responses about saving programs/files to secondary storage or about moving programs to virtual memory, as these are not uses of this record.

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

• Each teacher can keep their own files/desktop separate (1) so other teachers cannot see or change their work (1)
• Each teacher's work is saved under their own account (1) so they can find their files easily when they log in (1)
• The operating system knows which teacher is logged in (1) so it can apply the right access rights to that person (1)
• Each teacher can set up their own desktop/settings (1) so the laptop is set up the way they like to work (1)

Do not accept responses about the laptop running faster or having more storage because it has more accounts.

Do not accept 'so they can log in' without saying why having separate accounts helps.

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

• It allows the operating system/OS to communicate with the device/printer (1) because it translates the commands into signals the device understands (1)
• It contains/sends the instructions/commands needed by a particular device (1) so the device carries out the correct actions (1)
• It controls the device/printer (1) by sending commands/signals to it (1)
• Different devices need different commands (1) so each one needs its own driver to work with the operating system (1)

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

Do not accept 'it drives/controls the device' on its own without saying how, e.g. by sending commands/signals.

Do not accept hardware/a physical device (a device driver is software).

Do not accept 'it connects the printer to the computer' or 'it installs the printer' without saying that it provides the instructions/commands for the device.

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

• A process is created for the program (1) so that its instructions can be loaded into RAM (1)
• The process is put into the ready state (1) so that it can wait for the CPU to become available (1)
• The operating system adds the process to a queue of ready processes (1) so the scheduler can choose it when the CPU is free (1)
• The operating system allocates the resources the process needs (1) so that it can start running when it is given CPU time (1)

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

Allow 'main memory' for RAM.

Do not accept 'the browser is downloaded/loaded from the internet'.

Do not accept 'the program is run immediately on the CPU' without the ready step.

Indicative content

Allocating space

• The operating system checks that there is enough free space before a file is saved, so a large photograph does not make the save fail.
• The operating system finds free space on the disk and allocates it to the new file, so the file's data has somewhere to be written.
• Disk space is allocated so that a file is not written on top of data that already belongs to another file.
• When a file is deleted, the operating system marks its space as free so it can be used again by the next document that is saved.

Keeping track

• The operating system keeps a record of the name, size and location of every file, so it knows where each file is stored.
• The record is updated whenever a file is saved, renamed or deleted, so it still matches what is on the disk.
• The operating system uses this record to find a file again, so an employee can open a document or photograph that was saved earlier.
• The record lets the operating system tell the two employees' documents and photographs apart, even though they are all on the same disk.

Without this management

• Two files could be given the same space, so one document would overwrite another and the work would be lost.
• The operating system would not know where a file is stored, so a saved document could not be found and opened again.
• Space used by deleted files might never be freed, so the disk would fill up and new files could not be saved.

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 both the allocation of space and the tracking of files, with at least one consequence of no management linked to its cause. Reference to a file being split across blocks that are not next to each other, or to the record holding the location of each block, is Level 3 detail and is not required.

Basic, unlinked points with no application to the business's documents or photographs, and a consequence such as 'files would be lost' with no cause given, are limited to Level 1; to reach Level 2 a point must be linked to a reason (for example, the record is kept so a document can be found again) and be applied to the context. Do not accept defragmentation, process scheduling, user management, peripheral management, or backup and antivirus scanning, as file management.