Homework 2 ECE 4310 Fall 2018 Gabriel Kuri

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Homework 2 ECE 4310 Fall 2018 Gabriel Kuri 4 Problems - 50 pts total 1 (5 pts) Explain in detail the difference between preemptive and non-preemptive scheduling. 2 (15 pts) Consider the following processes arriving at the ready queue and dispatched to a single core CPU: PID Arrival Time Burst (ms) Priority 10 0 5 2 11 1 7 1 12 3 2 9 13 8 15 4 14 17 4 11 15 20 12 6 Using the following scheduling algorithms: First-come first-served (FCFS) Preemptive shortest job first (PSJF) Preemptive Round-robin with 4 ms quantum Priority with a priority aging of +1 every 5 ms Answer the following: (a) Draw a Gantt chart showing the arrival time and run times for each process. (b) Calculate the wait time for each process and average waiting time. (c) Calculate the turnaround time for each process. 3 (15 pts) The sleeping barber problem is a classic process synchronization problem, where a barber shop has one barber, one barber chair, and n chairs for waiting customers, if any, to sit and wait. If there are no customers present, the barber sits down in the barber chair and sleeps. When a customer arrives, he has to wake up the sleeping barber. If additional customers arrive while the barber is cutting a customer's hair, they either sit down (if there are empty chairs) or leave the shop (if all chairs are full). Consider a slight modification to the classic problem, where there are m barbers and n chairs at the barber shop, instead of just one. Write a program in C or pseudocode using semaphores to implement this problem (with m barbers and n barber chairs). 1 4 (15 pts) Recall the various deadlock detection and prevention algorithms we've discussed in class and consider the following snapshot of a system with five processes (P10, P11, P12, P13, P14) and four resources (R1, R2, R3, R4). R1, R2, R3, and R4 have a total of 5, 7, 10, and 11 resources, respectively. There are no current outstanding queued unsatisfied requests. Table 1: Allocation Table 2: Max Need PID R1 R2 R3 R4 PID R1 R2 R3 R4 10 0 0 1 2 10 0 0 3 2 11 1 0 0 0 11 2 7 5 0 12 1 0 1 4 12 5 6 5 6 13 0 3 5 1 13 4 3 5 6 14 2 3 3 2 14 0 6 5 2 Is the system currently in a safe or unsafe state? If safe, provide the process execution order. 2.

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