Computer Architecture and Organisation

Question

Q No: 48
 

The access time of cache memory is 15 ns and main memory is 100 ns. It is also estimated that 70% of memory requests are for read and remaining are for write. The list ratio for read access is only 80%. A write through procedure is used. For write operation, pages are always available in cache so the total access time (in ns) is?

Correct Answer: 54.5    Status: unattempted

Comments

Write Through Technique is used so CPU perform Simultaneous write operation in both cached memory and main memory H_w=1

Tavg(read)=hr(tc)+1-(hr)(T_m+Tc)

=0.8*15+0.2*115

=35

Tavgwrite=1*100

Tavg=0.7*35+0.3*100

=24.5+30

54.5ns