Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• The program (and its data) is copied/loaded from secondary storage into main memory/RAM (1) so that the CPU can fetch/execute its instructions (1)
• An area of main memory is allocated/reserved for the program (1) that is large enough to hold the program and its data (1)
• The operating system checks that there is enough free main memory (1) before the program can be started/loaded, otherwise it cannot run/an error is reported (1)
• The operating system keeps a record of the memory addresses used by the program (1) so that its instructions and data can be found when it runs (1)

Allow 'loaded into RAM', 'stored in memory' and 'put into main memory' as equivalent to copied into main memory.

A single statement that the program is loaded/stored in main memory, with no linked development, can be given one mark only.

Do not accept descriptions of the CPU fetching/executing instructions that do not refer to the operating system loading or allocating memory.

Do not accept responses about virtual memory (moving processes to secondary storage) or about which process runs next on the CPU.

Do not accept the program being run from secondary storage/hard disk.

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 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.