Thursday, July 19, 2012

What is difference between paging & swapping???

Swapping: Whole process is moved from the swap device to the main memory for execution. And vise-versa post execution. Process size must be less than or equal to the available main memory. It is easier to implement and overhead to the system. Swapping is are rigid, paging more flexible.

Paging: Only the required memory pages (data areas, but not instructions which are available from local or remote file systems) are moved to main memory from the paging disk device for execution.
Process size does not matter. Gives the concept of the virtual memory.  It provides greater flexibility in mapping the virtual address space into the physical memory of the machine.  Allows more number of processes to fit in the main memory simultaneously. Allows the greater process size than the available physical memory. Demand paging systems handle the memory more flexibly.

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