Question

Draw a Gantt chart that shows the completion times for each process
using round robin CPU scheduling, with a time slice of 60.
p1|p2q|p3|p4|p5|
process 120|60|180|50|300|
time slice=60
p1-service time
p2- service time
p3-service time
p4-service time
p5-service time

Answer 1

To create a Gantt chart for the processes using Round Robin scheduling with a time slice of 60, we first need to define the processes with their respective burst times:

- **P1**: 120
- **P2**: 60
- **P3**: 180
- **P4**: 50
- **P5**: 300

### Round Robin Scheduling

**Time Slice = 60**

We will follow the Round Robin scheduling approach, where each process is given a maximum of 60 units of CPU time before the scheduler moves on to the next process in the queue.

### Process Iterations
- **P1** executes for 60 time units: remaining time = 120 - 60 = 60
- **P2** executes for 60 time units: remaining time = 60 - 60 = 0 (completed)
- **P3** executes for 60 time units: remaining time = 180 - 60 = 120
- **P4** executes for 50 time units: remaining time = 50 - 50 = 0 (completed)
- **P5** executes for 60 time units: remaining time = 300 - 60 = 240

Now we repeat for remaining processes:

- **P1** executes for 60 time units: remaining time = 60 - 60 = 0 (completed)
- **P3** executes for 60 time units: remaining time = 120 - 60 = 60
- **P5** executes for 60 time units: remaining time = 240 - 60 = 180

Then, we repeat for the next cycle:

- **P3** executes for 60 time units: remaining time = 60 - 60 = 0 (completed)
- **P5** executes for 60 time units: remaining time = 180 - 60 = 120

Finally, we have one last cycle:

- **P5** executes for 60 time units: remaining time = 120 - 60 = 60
- **P5** executes for 60 time units: remaining time = 60 - 60 = 0 (completed)

### Gantt Chart

Now we can represent this in the Gantt chart format, indicating the order and completion levels:

```
| P1 | P2 | P3 | P4 | P5 | P1 | P3 | P5 | P3 | P5 |
| 0 | 60 | 120 | 170 | 220 | 280 | 340 | 400 | 460 | 520 | 600 |
0 60 120 170 220 280 340 400 460 520
```

### Completion Times
To summarize the completion times:
- **P1**: Completes at time 280
- **P2**: Completes at time 120
- **P3**: Completes at time 460
- **P4**: Completes at time 170
- **P5**: Completes at time 600

This Gantt chart representation allows for a visual understanding of how the Round Robin scheduling executed each process over time with the given time slice.