FCFS process and examples
The process that requests the CPU first is allocated the CPU first
Criteria: Arrival Time
Decision mode: Non-preemptive
Data-Structure: Queue
Example:
First we design a Gantt Chart according to arrival time and burst time to follow FCFS.
Now calculate Completion Time (CT) from Gantt Chart
Now we calculate Turn Around Time (TAT) and as per the formula we know
Turn Around Time (TAT)= Completion Time (CT) – Arrival Time (AT)
We can also calculate Wait Time (WT) using the formula:
TAT = WT + BT
WT = TAT - BT
In the case of Non-Preemptive waiting time and first Response Time (RT) is same.