EMAT in OS

Question

In a system, with virtual memory the memory access time is 400 nanoseconds, if the page fault service time is double the memory access time, then what is the effective memory access time (in nanoseconds) for 50 percent of page faults?

 

Solution 1:
EMAT=P(PS) + m
P=0.50 , PS=800, m=400so ans is 800.

Solution 2:

EMAT=1/2 * 400  +1/2 * 800 =600

 

Which solution is more appropriate in GATE point of view if Numerical Type question is given without options .

Answer 1

Formula to calculate EMAt

Emat = p*m +(1-p)*S

so second 1 is the correct solution.

i didnt understand how u r doing  solution 1 .

Comments

mean Solution 2 is right?

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yes i

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Many previous year gate questions are solved on "Solution 1" .

Question Link  https://gateoverflow.in/2122/gate2011-20-ugcnet-june2013-ii-48

If we will solve this question using Solution  1 we will get around 29.something .(Close to 30 )