Problem 2: (18 points) Provide short answers for the following questions. There are four parts in this question and you must answer at least three. Your answers must be brief and you should be able to answer each question in no more than three sentences (with the exception of the cases where sample code is required). Your answer for the entire question 2 MUST fit on the one page provided. Any violation of these conditions will result in no credit. (a) Does internal forwarding always eliminate all stall cycles due to data hazards in a pipeline? You can justify/explain your answer by using a (very) simple pseudo (assembly) code. (b) Consider a processor with the following CPI for each type of instruction, and the instruction mix for a particular benchmark. Determine the effective CPI for this benchmark Load/Store | Cond. Branch Jumps 1.2 ALU CPI 1.5 30% 10% nst. Mix | 40% | 20% (c) Your computer vendor offers three optional enhancements for the same price. The speedup of each enhancement A can only be applied to 50% of the code-the remaining code has to be executed in un- enhancement and its applicabity (usability in pre-enhanced instructions) is given below. (For example, enhanced mode.) If you can only buy one optional enhancement, which one should you buy? Speedup Applicability A: 5x 50% of pre-enhanced instructions | 10x C: 100x | 40% of pre-enhanced instructions 30% of pre-enhanced instructions B: (d) Suppose you have installed a disk drive with an MTTF of 1.5 x 10 hours. How long can you run your computer before you would expect the drive to fail? If it takes 3 days to replace a disk drive, how many "nines" is your disk drive's availability