Question
Draw a Gantt chart that shows the completion times for each process
using round robin CPU scheduling, with a slice time of 60 and service times of 120, 60, 180, 50, and 300
using round robin CPU scheduling, with a slice time of 60 and service times of 120, 60, 180, 50, and 300
Answers
GPT-4o mini
To create a Gantt chart for a Round Robin CPU scheduling algorithm with the specified slice time and service times, we'll first break down the problem and then visualize it.
### Given Data:
- **Slice Time (Time Quantum):** 60 ms
- **Service Times for Processes:**
- P1: 120 ms
- P2: 60 ms
- P3: 180 ms
- P4: 50 ms
- P5: 300 ms
### Calculating the Completion Times:
1. **P1:** Needs 120 ms. In the first round, it runs for 60 ms, leaving 60 ms (remaining time = 60 ms). In the second round, it completes the remaining 60 ms.
2. **P2:** Needs 60 ms. Runs for 60 ms in the first round (it will finish in this timeframe).
3. **P3:** Needs 180 ms. Runs for 60 ms, leaving 120 ms (remaining time = 120 ms). In the second round, it runs for another 60 ms, leaving 60 ms (remaining time = 60 ms). In the third round, it will complete its remaining time of 60 ms.
4. **P4:** Needs 50 ms. It runs for 50 ms in the first round (it will finish in this timeframe).
5. **P5:** Needs 300 ms. Runs for 60 ms in the first round, leaving 240 ms (remaining time = 240 ms). In the second round, it runs for another 60 ms, leaving 180 ms (remaining time = 180 ms). In the third round, it runs for another 60 ms, leaving 120 ms (remaining time = 120 ms). In the fourth round, it runs for another 60 ms, leaving 60 ms (remaining time = 60 ms). In the fifth round, it finally completes its remaining time of 60 ms.
### Order of Execution:
1. **1st Round**:
- P1 (0-60)
- P2 (60-120)
- P3 (120-180)
- P4 (180-230)
- P5 (230-290)
2. **2nd Round**:
- P1 (290-300)
- P3 (300-360)
- P5 (360-420)
3. **3rd Round**:
- P3 (420-480)
- P5 (480-540)
4. **4th Round**:
- P5 (540-600)
### Gantt Chart Representation:
```
| P1 | P2 | P3 | P4 | P5 | P1 | P3 | P5 | P3 | P5 |
0 60 120 180 230 290 300 360 420 480 540 600
```
### Completion Times:
- P1 completes at time 300 ms.
- P2 completes at time 120 ms.
- P3 completes at time 480 ms.
- P4 completes at time 230 ms.
- P5 completes at time 600 ms.
This Gantt chart illustrates how each of the processes executes in a Round Robin manner under the defined slice time, along with their respective completion times.
### Given Data:
- **Slice Time (Time Quantum):** 60 ms
- **Service Times for Processes:**
- P1: 120 ms
- P2: 60 ms
- P3: 180 ms
- P4: 50 ms
- P5: 300 ms
### Calculating the Completion Times:
1. **P1:** Needs 120 ms. In the first round, it runs for 60 ms, leaving 60 ms (remaining time = 60 ms). In the second round, it completes the remaining 60 ms.
2. **P2:** Needs 60 ms. Runs for 60 ms in the first round (it will finish in this timeframe).
3. **P3:** Needs 180 ms. Runs for 60 ms, leaving 120 ms (remaining time = 120 ms). In the second round, it runs for another 60 ms, leaving 60 ms (remaining time = 60 ms). In the third round, it will complete its remaining time of 60 ms.
4. **P4:** Needs 50 ms. It runs for 50 ms in the first round (it will finish in this timeframe).
5. **P5:** Needs 300 ms. Runs for 60 ms in the first round, leaving 240 ms (remaining time = 240 ms). In the second round, it runs for another 60 ms, leaving 180 ms (remaining time = 180 ms). In the third round, it runs for another 60 ms, leaving 120 ms (remaining time = 120 ms). In the fourth round, it runs for another 60 ms, leaving 60 ms (remaining time = 60 ms). In the fifth round, it finally completes its remaining time of 60 ms.
### Order of Execution:
1. **1st Round**:
- P1 (0-60)
- P2 (60-120)
- P3 (120-180)
- P4 (180-230)
- P5 (230-290)
2. **2nd Round**:
- P1 (290-300)
- P3 (300-360)
- P5 (360-420)
3. **3rd Round**:
- P3 (420-480)
- P5 (480-540)
4. **4th Round**:
- P5 (540-600)
### Gantt Chart Representation:
```
| P1 | P2 | P3 | P4 | P5 | P1 | P3 | P5 | P3 | P5 |
0 60 120 180 230 290 300 360 420 480 540 600
```
### Completion Times:
- P1 completes at time 300 ms.
- P2 completes at time 120 ms.
- P3 completes at time 480 ms.
- P4 completes at time 230 ms.
- P5 completes at time 600 ms.
This Gantt chart illustrates how each of the processes executes in a Round Robin manner under the defined slice time, along with their respective completion times.