Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• The memory (that was) used by the program is freed/released/marked as free (1) so it can be allocated/reused by another program/process (1)
• The operating system's memory allocation table/record (of memory in use) is updated (1) to show that the program's memory locations/blocks are now free/available (1)
• The program's instructions/data are removed/overwritten in main memory (1) so the space they used is no longer reserved for that program (1)
• The memory pages/blocks allocated to the program are returned to the list of free pages/blocks (1) that can be used when the next program is loaded (1)

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

Do not award two marks for the same idea described twice (e.g. the memory is freed and added to a list of free blocks); the two marks must come from two different linked descriptions.

Do not accept responses about closing the program window, stopping/terminating the program/process, saving the file or deleting the program from secondary storage/the hard disk.

Ignore statements that main memory is 'managed'/'cleaned up' with no development.

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

• The operating system switches rapidly between processes (1) so each process runs for a short time slice before the next one starts (1)
• Each process is given a small amount of CPU time (1) so the CPU moves on to another process when that time is up (1)
• The operating system chooses which process to run next (1) so the CPU is shared between the programs (1)
• Processes take turns to use the CPU (1) because the CPU is so fast the user does not notice the switching (1)
• Only one process can run on the CPU at a time (1) so the operating system must swap processes in and out quickly (1)

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

Allow 'time slice' / 'time quantum'.

Do not accept 'the computer has more than one CPU' / 'each program runs on its own CPU'.

Do not accept 'the CPU does two things at once' without saying processes take turns/are switched.

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

• The operating system uses the printer's device driver to communicate with the printer (1) so the print job is sent as commands the printer can carry out (1)
• The operating system holds print jobs in a queue/buffer (1) because the computer sends data faster than the printer can print it (1)
• The operating system reports the printer's status to the user (1) so the user knows what to do when there is a problem such as the paper running out (1)
• The operating system handles interrupts/signals from the printer (1) so a problem such as a paper jam is dealt with while other programs carry on running (1)

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

Allow a point about the operating system loading/installing the device driver for a new printer (1) provided the second mark gives a reason that is not the same as the driver communication point, e.g. so the new printer can be used/controlled by the operating system (1)

Award 1 mark for stating that print jobs are held in a queue/a buffer; the second mark needs the linked reason that the printer prints more slowly than data is sent.

Do not accept restating the question, e.g. 'it manages the printer' or 'it controls the peripherals', without saying how or why.

Do not accept 'it lets the printer connect to the computer' or 'it stops the printer being damaged' without a linked reason.

Do not accept 'it makes the printer print faster' as the operating system cannot increase the printer's speed.