In a two -level virtual memory, the memory access time for main memory, $${t_M} = {10^{ - 8}}\sec $$ and the memory access time for the secondary memory, tag $$ = {10^{ - 3}}.$$ What must be the hit ratio, $$H$$ such that the access efficiency is within $$80$$ percent of its maximum value?

Under paged memory management scheme simple lock and key memory protection arrangement may still be required if the $$........$$ processors do not have address mapping hardware.

State whether the following statement are TRUE or FALSE with reason. The data transfer between memory and $${\rm I}/O$$ devices using programmed $${\rm I}/O$$ is fasterthan interrrupt-driven $${\rm I}/O$$.

A certain moving arm disk-storage device has the following specifications:
Number of tracks per surface $$=4004$$
Track storage capacity $$=130030$$ bytes
Disk speed $$=3600$$ rpm
Average seek time $$=30$$ m secs.
Estimate the average latency the disk storage capacity and the data transfer rate.