consider a two

-

tier memory 

system consisting of cache (SRAM) and main memory (D

RAM). 

The cache access time is 1 

nsec and the main memory access time is 50 nsecs. (1 nsec = 1 

 ́

10

-

9

secs).

(a)

What is the overall memory access time given a cache hit rate of 95%? 

(b)

What will the cache hit rate need to be if the overall memory access time in (a) is to be 

halved?