Effective memory access time

Question

Comments

1.10ms??

Answer 1

EMAT= NoPageFault *  m/m access time + PageFault * ( Modified * Service time + NotModified * ServiceTime)

EMAT= $0.95*200*10^{-6}+0.05*(0.5*15+0.5*7)$

EMAT=$0.55019 \ msec$

0.55019 msec is the correct answer

Comments

If there is no page fault then why will it access the memory?

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if there is no page fault then our page is in main memory, to get that page we need a memory access, if page fault occurs then then a new page is brought to main memory and some other page is replaced in place of it based on some page replacement policy, here two cases arise when we are are replacing the page we check either is modified or not.

If a page is modified first its value is written into main m/m then a new page is replaced and if not modified we simply replaces it, this whole time comes under Page service time which comed into picture in case of page fault.

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@Ashwani Kumar 2  how it will result 11 msec?

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@saxena0612 by mistake :p