Perform capacity planning for a two level memory hierarchy system. The first level, M, is a cache with three capacity choices 64 Kbytes, 128 Kbytes and 256 Kbytes. The second level, M, is a main memory with a 4 Mbyte capacity. Let C, and C, be the cost per byte and t, and t, the access times for M, and M, respectively. Assume C,=20C, and t;=10t,. The cache hit ratios for the three capacities are assumed to be 0.7, 0.9 and 0.98 respectively. i) What is the average access time t, in terms of t;=20ns in the three cache designs? ii) Express the average byte cost of the entire memory hierarchy if C =$0.2/Kbyte. iii) Compare the three memory designs and indicate the order of merit in terms of average costs and average access times respectively. Choose the optimal design based on the product of average cost & average access times. average aces time