Answer Happy

Below is an implementation of a barber who can perform hair cuts on people, one at a time. Furthermore, there is a function that any number of people can call at any time (including at the same time) to get a hair cut. customer and barber done are counting semaphores. barber () while (true){ wait (customer); cut hair(): signal (barber_done); customer.get_hair.cut() signal (customer); valt (barber done): pay(); How should the two semaphores be initialized before either of these functions is called? The barber cannot cut hair unless there is a customer and a customer cannot pay until the work is done. O a. customer = 1; barber done = 1 O b. customer 1: barber done 0. O c. customer = 0; barber done = 0 O d. customer = 0; barber done = 1.

Consider the following set of processes, with the length of the CPU bursts given in milliseconds, assuming all processes arrived at the same time: Process Arrival Time Burst Time Priority P1 1 15 4 P2 5 5 1 P3 5 7 3 P4 7 11 2 (a) Draw a Gantt chart that show the execution of these processes using the preemptive shortest job first (b) Draw a Gantt chart that show the execution of these processes using the non-preemptive priority (a smaller number implies a higher priority) (c) Draw a Gantt chart that show the execution of these processes using the Round-robin with quantum = 5 (d) Compute the average waiting time (over all processes) for each of the scheduling algorithms. Show your work. A- B I # E III H A