Operating Systems

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** (non-demand) Paging

Simplest scheme to remove the requirement of contiguous physical memory. Example: Assume a decimal machine with page size = frame size = 1000.
Assume PTE 3 contains 459.
Then virtual address 3372 corresponds to physical address 459372.

Properties of (non-demand) paging.

Address translation

Choice of page size is discussed below .

4.3: Virtual Memory (meaning fetch on demand)

Idea is that a program can execute even if only the active portion of its address space is memory resident. That is, we are to swap in and swap out portions of a program. In a crude sense this could be called “automatic overlays”.

Advantages

Disadvantages

** 4.3.1: Paging (meaning demand paging)

Fetch pages from disk to memory when they are referenced, with a hope of getting the most actively used pages in memory.