Correct Answer - Option 2 : 360 ns
Concept:
The read access time is given as:
TM = h × TC + (1 – h) × TP
TM is the average memory access time
TC is the cache access time
TP is the access time for physical memory
h is the hit ratio
Analysis:
Given:
H = 0.9, Tc = 100, Tm = 1000
Now read access time
= HTc + (1 - H)(Tc + Tm)
= 0.9 × 100 + 0.1 × (100 + 1000) nsec
= 200 nsec
Total access time
= (0.8 × 200 + 0.2 × 1000) nsec = 360 nsec