Given the following set of taskswith the specified estimated

Given the following set of tasks---with the specified estimated running times, arrival time, and priority---determine the mean process turnaround time with Round Robin scheduling. Round Robin is also called Preemptive multiprogramming. Here, each job gets its fair share of CPU. (Note: Show working details in your worksheet.)

  Task    

  Estimated running time  

  Arrival time  

  Priority  

  A  

  10  

  0  

  3  

  B  

  6  

  0  

  5  

  C  

  2  

  0  

  2  

  D  

  4  

  0  

  1  

  E  

  8  

  0  

  4  

Solution

Consider the following set of tasks with estimated running times, arrival time, and priority --->

(time quatum is not given so we assume it 10)

Now Gantt chart for Priority based Round Robin CPU scheduling---->

|-----------|-----------|----------|------------|------------|
|    D |    C | A |    E      |    B    |
|-----------|-----------|----------|------------|------------|
0 4    6    16     24    30

All task arrive at time 0 and no time quantum is given, only priority is given so all task completed according to priority RR scheduling algorithm.

mean process turnaround time = (16+30+6+4+24)/5 = 80/5 = 16 unit

  Estimated running time  

  Arrival time  

  Priority  

  A  

  10  

  0  

  3  

  B  

  6  

  0  

  5  

  C  

  2  

  0  

  2  

  D  

  4  

  0  

  1  

  E  

  8  

  0  

  4