a$.$ There are several ways in which a CPU may be placed in an idle state. One of which is through special control signals; Bus Request and Bus Grant. Discuss the process from when CPU relinquish control of buses until it gains it back from DMA.

b$.$ Highlight the differences between Cache and RAM

$6$ marks

$6$ marks

c$.$ With the use of a diagram describe the DMA transfer

$8$ marks

Question $4$: Memory Organization $(20$ marks$)$

a$.$ Consider the FIFO and LRU algorithm for the following page references $=[1,2,3,4\mathrm{.}2,1\mathrm{.}5\mathrm{.}2,1,2,3,4,3,2,5]$ with a frame size of $4.$

i$.$ find the number of page faults for each algorithm.

$9$ marks

ii$.$ Of the two algorithms, which is the preferred algorithm based on the output.

$2$ marks

b$.$ Briefly discuss the memory hierarchy in terms of size, access time and speed.

$9$ marks