PAGING

Question

Assume that we have a paging system with page table stored in memory
a. If a memory reference takes 200 nanoseconds how long does a paged memory reference take
b. If we add associative registers and 75% of all page table references are found in the associative registers, what is the effective memory reference time? Assume that finding a page table entry in the associative registers takes 1 ns, if the entry is there.

Comments

A. 400ns

i.e. translation time followed by accessing time

B. 251

0.75*201+0.25*401 = 251ns

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could you elaborate a bit more?

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For first one, first we are trying to get the address of the physical page frame for this first we have to access the page table so accessing page table cause 200 ns bcz it is stored in mm. And then followed by accessing the required frame which is also present in mm thus 200 ns for this also. Total 400ns.