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 user/file is given permissions/access rights (1) so other users cannot read/write/open/change that user's files (1)
• A user may be given read-only/read access to a file (1) so they cannot edit/delete/change it (1)
• Each file is given permissions/access rights for different users (1) so the operating system allows/refuses access depending on which user is logged in (1)
• The operating system checks a user's permissions/access rights when a file is opened (1) so a user with read-only/read access cannot save/delete changes (1)

Do not accept responses about asking for a password/username, as this checks who the user is, not what they are allowed to do.

Do not accept 'files are protected/safe' or 'access rights protect files' without saying how access is limited (e.g. read-only access, permissions for different users).

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

• Data is sent to/received from the correct peripheral (1) because the operating system controls the transfer of data between the computer and each device (1)
• A new peripheral can be used as soon as it is connected (1) because the operating system installs/loads the correct device driver for that device (1)
• Data can be sent to a slow peripheral such as a printer (1) because the operating system stores it in a buffer/print queue until the device is ready to receive it (1)
• The user is told when a peripheral has a problem (1) because the operating system receives status information from the device and reports the error to the user (1)

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

Allow specific peripherals as the example (e.g. a mouse, a printer) provided the reason says what the operating system does.

Allow 'the operating system responds to an interrupt from a device' as a point, with the reason that the device is signalling that it needs attention/has finished its job.

Do not accept 'the operating system manages/controls the peripherals' or 'it lets the devices be used'/'the peripherals work correctly' on their own, as these repeat the question without saying what the operating system does.

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

• The operating system checks usernames/passwords at login (1) so only allowed users can access the computer (1)
• The operating system stores a list/database of users and passwords (1) so it knows who is allowed to log in (1)
• The operating system sets access rights/permissions for each user (1) so a user can only open/edit their own files (1)
• The operating system restricts programs/drives/settings by user (1) so certain users cannot change them (1)
• The operating system keeps each user's files separate (1) so one user cannot access another user's private files (1)

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

Do not accept 'so the computer is safe/secure' without saying what is protected and from whom.

Do not accept answers that say user management makes the computer faster.