1. Consider a system using non-preemptive Shortest Job First algorithm. The systems is running tasks P1, P2, P3, and P4, whose arrival times are 0, 1,2, and 3 and whose CPU time bursts are 10, 1, 3, and 20, respectively. a. Draw a Gantt chart showing the execution schedule. b. What is the average waiting time? Assumption: The CPU time bursts are in measures of milliseconds (ms) 2. Now, assume the system in previous uses a preemptive scheduler. a. Draw a Gantt chart showing the schedule. b. Whatis the average waiting time? Assumption: The CPUtime bursts are in measures of milliseconds (ms)