10 06 2022 E TS

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Advanced Operating Systems - Part A, June 10th 2022 Exercises and solutions Exam finalization Question 1.1 This is part A of the AOS’s exam and today you are finalising your entire grade. You must express now how you have finalised part B. The answer is mandatory for the entire exam. Exercise 2 — Open and closed questions (Points 15) Question 2.1 (Points 5) Describe a reader/writer lock by using pseudocode for the readers’ and writers’ locking and unlocking operations. Question 2.2 (Points 5) Describe goals and the principles of the Linux scheduler multi-core load balancer. Question 2.3 (Points 3) Describe the goals and the basic mechanisms and policies behind file systems equipped with journaling Question 2.4 (Points 2) How does secure boot work? Exercise 3 — Scheduling (Points 7) Question 3.1 (Points 7) Given task set in the following table, • draw the Gantt diagram of the schedule obtained by applying the Round Robin (RR) scheduling algorithm with quantum q = 2 (ignoring any overhead) and • fill the last column in table according to the above scheduling algorithm • considering a non-null preemption overhead, what would be, for this specific task set, the minimum value of q that guarantees a minimal overhead? Justify the answer. Note that, if any task arrives at the same time of a preemption, the arrival task must be inserted first in the ready queue and, then, the preempted task. Solution 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 Task Arrival time ( Ai) Completion time ( Ci) Turnaround time ( Zi) T1 0 3 7 T2 1 10 25 T3 2 5 16 T4 8 7 19 T5 10 2 7 The minimum value of q for this task set to avoid preemptions is q = 10, because the task T2 has a computation time of 10 and…