Consider an interactive system with a CPU and two disks. The following measurement data was obtained by observing the system:

• Observation interval = 17 minutes

• Mean think time = 12 seconds

• Number of completed transactions during observation interval = 1,600

• Number of completions at CPU = 1,600

• Number of fast disk accesses = 32,000

• Number of slow disk accesses = 12,000

• CPU busy time = 1,080 seconds

• Fast disk busy time = 400 seconds

• Slow disk busy time = 600 seconds

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1. Give asymptotic bounds on throughput and response time as a function of the number of terminals.

2. Now consider the following modifications to the system:

1. Move all files to the fast disk.

2. Replace the slow disk by a second fast disk.

3. Increase the CPU speed by 50% (with original disks),

4. Increase the CPU speed by 50% and balance the disk load across the two fast disks.

For each of these four modifications, compute and graph the effects on the original system. Explain in words the effect when the multiprogramming level, N, is small and when Nis large.