First Come First Serve (FCFS) CPU Scheduling Algorithm with Example

In this video, we will be covering one of the CPU scheduling algorithms : First-Come-First-Serve (FCFS) Algorithm in detail.

FCFS Algorithm:
It allocates the CPU to the process requesting the CPU first, then to the second requesting process and so on. 
It performs scheduling based on the arrival times of processes. It uses the First-In-First-Out (FIFO) queue for this purpose. New processes are attached at the rear (tail) of the queue whereas, processes are removed from the head (front) of the queue. It can be implemented as preemptive as well as non-preemptive. 

Advantages of FCFS Algorithm:
1) Simplest of all scheduling algorithms 
2) Easy to understand 
3) Easy to implement 
4) Performs better with processes having longer burst time 
5) Free from starvation: Every process that wants to access the CPU, will be allocated the CPU after all the processes arriving before it have got their turn on the CPU. (No indefinite waiting for CPU) 

Disadvantages: 
1) Waiting time of processes increases as compared to other algorithms. 
2) Less efficient than other scheduling algorithms. 
3) A long process makes all smaller processes to wait for its completion. 
4) It performs better for the processes with longer burst time. 
5) Favours CPU bound processes over I/O bound processes. 
6) Not suitable for time-sharing system where each user expects an interactive system with regular time intervals. 
 
First Come, First Serve – CPU Scheduling | (Non-preemptive)
https://www.geeksforgeeks.org/first-come-first-serve-cpu-scheduling-non-preemptive/