Chapter 15, Problem 24QAP

Segment Base (original) Length Base (after compaction) 0 100 300 1 1400 600 2 450 100 3 3200 80 4 2200 500 5 3300 33 1. Given the original base addresses, what are the physical addresses for the following logical addresses? If it's an invalid address, just write "invalid". Note that (X, Y) => segment X, offset Y a) (0,350) b) (1,599) c) (2,50) d) (3,81) e) (4,300) f) (5.0) g) (5,34)

Process Allocation A Max BCDABC D A Available B C PO 3 0 2 1 4 2 4 2 1 0 0 P1 0 1 0 1 0 2 2 2 P2 1 2 0 0 3 2 1 0 P3 0 1 1 2 1 1 1 2 P4 0 0 1 1 1 - 0 2 1 a) What is the content of the matrix Need? Process PO P1 P2 P3 P4 A Need BC D D ° b) Is the system in a safe state? If yes, give a safe sequence of processes. If not, explain why the system is not in a safe state. c) If a request from process P4 arrives for (1,0,0,0), can the request be granted immediately? Please state the reason.

Consider N processes sharing the CPU in a round-robin fashion (N>=2). Assume that each context switch takes S ms and that each time quantum is Q ms. For simplicity, assume that processes never block on any event and simply switch between the CPU and the ready queue. Also, assume that a process is still in the ready queue while a context switch is happening. a) What happens if Q is much smaller than S? What happens when Q→→ ∞, i.e. is much larger than the maximum turnaround time of all the processes? Be brief (1-2 sentences max) in your answer. b) If you use RR for scheduling, which of the three performance metrics (waiting, response, turnaround time) is more likely to be improved? Why (1-2 sentences max)?