Computer Architecture & Operating Systems

Question 1 (1 Mark) If computer A runs a program in 10 seconds and computer B runs the same program in 15 seconds, how much faster is A than B? Question 2 (6 Marks) Consider three different processors P1, P2, and P3 executing the same instruction set. • P1 has a 3 GHz clock rate and a CPI of 1.5. • P2 has a 2.5 GHz clock rate and a CPI of 1.0. • P3 has a 4.0 GHz clock rate and a CPI of 2.2. a) Which processor has the highest performance expressed in instructions per second? b) If the processors each execute a program in 10 seconds, find the number of cycles and the number of instructions. c) We are trying to reduce the execution time by 30% but this leads to an increase of 20% in the CPI. What clock rate should we have to get this time reduction? Question 3 (5 Marks) Suppose a program running on a single processor completes in 100 seconds. 10 seconds of this time is spent doing highly serial work, which cannot be parallelised. However, the remaining 90 seconds are spent doing independent multiply operations which are trivial to parallelise. Assuming we can parallelise the independent multiply operations perfectly. How many processor cores would we need to complete the program in 20 seconds? Question 4 (2 Marks) How many bytes are in a 64-bit word? Question 5 (4 Marks) Convert the following unsigned binary numbers to decimals. a) 10102 b) 1101102 c) 111100002 d) 00011000101001112 Question 6 (4 Marks) Convert the following hexadecimal numbers to decimal. a) A516 b) 3B16 c) FFEF16 d) D000000016 Question 8 (4 Marks) Perform the following additions of unsigned binary numbers. Indicate whether or not the sum overflows an 8-bit result. a) 100110012 + 010001002 b) 110100102 + 101101102