ace test CO-I

Question

If a level of memory hierachy has a hit rate of 75%, memory request takes 12 ns to complete if they hit in the level,and the memory request that miss in the level take 100 ns to complete. The average access time of the level is_________ns

Answer 1

average access time = hit * access time +miss* access time 

=( 75/100)*12 +(25/100)*100

= 9+ 25 

= 34 nsec 

Comments

Avg. access time = HT₁ + (1-H)(T₁+T₂ )

where T₁ is access time of the level 1 and T₂ is access time of level 2

     H is hit ratio

why this formula won't work since its stated that its a hierarchy

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actually by default we have to take simultaneously access method

hearchical acess method will be used when there is wording  like " block is transfered from l2 to l1 ".but in this question no such information is provided.so i have taken simultaneously access method here .

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Ok, got it..thanks...

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wt answer they have given ?