Calculate the waiting times and average waiting time for processes P1, P2, and P3 with burst times 4, 13, and…

Question

Calculate the waiting times and average waiting time for processes P1, P2, and P3 with burst times 4, 13, and 12 respectively, using the FCFS scheduling algorithm.

ScanSolve AI Tutor · Accepted Answer

Here's the calculation for the waiting times and average waiting time using the First Come First Served (FCFS) scheduling algorithm.

The waiting time for a process in FCFS (assuming all processes arrive at time 0) can be calculated as the sum of the burst times of all processes that arrived before it. The formula provided in your notes, $WT_i = (\sum_{j=1}^{i} BT_j) - BT_i$ , is equivalent to this, as it simplifies to the sum of burst times of all previous processes.

Given Burst Times:

P1: 4
P2: 13
P3: 12

Calculate the waiting time for P1.
P1 is the first process, so it starts immediately.
$WT_1 = 0$
Using the formula from your notes:
$WT_1 = (BT_1) - BT_1 = 4 - 4 = 0$
Calculate the waiting time for P2.
P2 waits for P1 to complete.
$WT_2 = BT_1$
Using the formula from your notes:
$WT_2 = (BT_1 + BT_2) - BT_2$ $WT_2 = (4 + 13) - 13$ $WT_2 = 17 - 13$ $WT_2 = 4$
Your calculation for P2 had a small error where you subtracted 4 instead of 13.
Calculate the waiting time for P3.
P3 waits for P1 and P2 to complete.
$WT_3 = BT_1 + BT_2$
Using the formula from your notes:
$WT_3 = (BT_1 + BT_2 + BT_3) - BT_3$ $WT_3 = (4 + 13 + 12) - 12$ $WT_3 = 29 - 12$ $WT_3 = 17$
Calculate the average waiting time.
The average waiting time is the sum of all waiting times divided by the number of processes.
$\text{Average Waiting Time} = \frac{WT_1 + WT_2 + WT_3}{3}$ $\text{Average Waiting Time} = \frac{0 + 4 + 17}{3}$ $\text{Average Waiting Time} = \frac{21}{3}$ $\text{Average Waiting Time} = \boxed{\text{7}}$

Calculate the waiting times and average waiting time for processes P1, P2, and P3 with burst times 4, 13, and 12 respectively, using the FCFS scheduling algorithm.

Answer

Step-by-step solution

Calculate the waiting time for P1.

Calculate the waiting time for P2.

Calculate the waiting time for P3.

Calculate the average waiting time.

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