The Gateway to Computer Science Excellence
0 votes
99 views

Consider a system using demand paging architecture

  • it takes $3ms.$ to service page fault if either empty frame is available or replaced page is not to be modified
  • takes $10ms.$ if replaced page is modified.
  • Main Memory access time is $1ms.$
  • and page to be replaced is modified $60$% of time.

The maximum acceptable page fault rate to get effective memory access time not more than $4ms.$ is_________(%)

in Operating System by Veteran (117k points) | 99 views

1 Answer

+2 votes
Best answer
Let the page fault rate be $p$, then

$ \Rightarrow p \times [0.4 \times 3 ms + 0.6 \times 10 ms] + (1-p) \times 1 ms \leq 4 ms$

$\Rightarrow 6.2p = 3$

$\Rightarrow p = 48 \% $
by Active (2.2k points)
selected by
0
why don't you add the memory access time at the time of page fault?

b'coz in the time of page first we service the page and the access main memory.

correct me if I am wrong
+1
From the time when page fault occurs to handling of the page fault is called page fault service time. That's why here no need to add memory access time

Related questions

Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true
50,647 questions
56,467 answers
195,381 comments
100,319 users