Originally Posted by xpi0t0s View Post
As I said in my VM post I don't really understand what it is you want to know. Have a look at these two Wikipedia articles:

For general information about caching:

For specific information about CPU caching:

Plus of course you should read articles linked from these pages.
this one of questions of is mano in his book. I tried to resolve it but im not sure.I sent my inquiry about write through in earlier thread , because I have confused in this part .

q:the access time of cache memory is 100 ns and that of main memory
1000 ns. it is estimated that 80% of the memory requests are for read
and the remaining 20% for write. the hit ratio for read access only is
0.9. a write -through procedure is used.
a- what is the average access time of the system considring only
memory read cycles?
b-what is the average access time of the system for both read asn
write requests?
c-what is the hit ratio taking into consideration the write cycles?