Practice Paper 2 GCE Computer Science H446/01 Computer Systems : Mark Scheme

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Practice Paper 2 GCE Computer Science H446/01 Computer Systems Mark Scheme Question Answer Marks Guidance 1 a i Paging is fixed size / physical divisions (1) Segmentation is dividing memor... y logically (i.e. will be variable size). (1) 2 (AO1.1) ii Uses virtual memory (1) which is an allocated area of a hard drive/secondary storage device.(1) Pages that aren’t needed are moved to VM (1) and moved back to physical memory when required (1) 4 (AO1.2) b i A signal to the processor indicating a device/process needs attention (1) 1 (AO1.1) ii Any five from: If the interrupt is of a lower/equal priority to the current process then the current process continues (1) If it is of a higher priority the CPU finishes its current Fetch-Decode-Execute cycle (1). The contents of the CPU’s registers are copied to a stack (1) in memory (1). The location of the appropriate interrupt service routine is loaded into the program counter (1) When the ISR is complete, the previous contents are popped from the stack and loaded back into the registers (1). [Show More]

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