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:

• Device drivers/drivers are used/installed (1) so the operating system can control/communicate with a peripheral (1)
• Data is transferred between the computer and a peripheral (1) so input can be read/output can be produced (1)
• Interrupts from devices/peripherals are handled (1) so the processor can respond when a device needs attention/has finished (1)
• Each peripheral is allocated to a process (1) so two processes do not try to use the same device at the same time (1)
• Print jobs are held in a queue/spooled (1) so several jobs can be sent to one printer and printed one at a time (1)
• Errors from a peripheral are handled/reported (1) so the program using the device does not crash (1)

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

Allow other valid functions of peripheral management that are explained, e.g. sending data to a peripheral in the correct format, reporting a device error to the user.

Do not accept 'it manages peripherals' / 'it controls the hardware' on its own as it repeats the question.

Do not accept 'it installs the printer' / 'it connects the peripheral' on its own without saying what the operating system does with the device or why.

Do not accept cleaning/maintaining a peripheral; that is not peripheral management by the operating system.