The computer spends 80% of the time computing and 20% waiting for the disk. The instruction mixes and the average cycles per instruction (CPI) for each type is: of CPI Instructions Integer Floating point Others 30 3 40 8 30 4 Consider 3 modifications to the computer. Compute the speedup for each. a) b) The processor is replaced with a new one that reduces the total computation time by 25%. The disk is replaced with a solid-state device that reduces the disk waiting time by 75%. The processor is replaced with a new one that has improved floating point performance. The average floating-point CPI is reduced to 4; all other aspects are unchanged. Which modification gave the best speedup? For the two modifications in part (i) that did not result in the best speedup, is it possible for them to achieve the speedup achieved by the modification in part (ii)? Show your work and explain your answer. d)