Gate 2017 pyq CAO | The read access times and the hit ratios for different caches in a memory
The read access times and the hit ratios for different caches in a memory hierarchy are as given below:
Cache Read access time (in nanoseconds) Hit ratio
I-cache 2 0.8
D-cache 2 0.9
L2-cache 8 0.9
The read access time of main memory in 90nanoseconds. Assume that the caches use the referred-word-first read policy and the write-back policy. Assume that all the caches are direct mapped caches. Assume that the dirty bit is always 0 for all the blocks in the caches. In execution of a program, 60% of memory reads are for instruction fetch and 40% are for memory operand fetch. The average read access time in nanoseconds (up to 2 decimal places) is _________