First Come First Serve Scheduling Algorithm

First Come First Serve (FCFS) Scheduling Algorithm

What is FCFS?

FCFS is a non-preemptive scheduling algorithm that executes processes in the order they arrive in the ready queue.

How FCFS Works

• Processes are added to the ready queue in the order they arrive.
• The process at the front of the queue is executed first.
• The process runs until it completes or is blocked.
• The next process in the queue is then executed.

Advantages

• Simple to implement.
• Easy to understand.
• No starvation, as every process gets a chance to execute.

Disadvantages

• Not efficient for processes with varying burst times.
• Can lead to long waiting times for processes that arrive later.
• Not suitable for interactive systems.

Example

Process	Arrival Time	Burst Time
P1	0	5
P2	1	3
P3	2	2

Gantt Chart

P1 (0-5), P2 (5-8), P3 (8-10)