FCFS is the simplest of all the Disk Scheduling Algorithms. In FCFS, the requests are addressed in the order they arrive in the disk queue. The requests which come first are served first.

Characteristics of FCFS :

The requests are served in the order they come.
Those who come first are served first.

Advantages of FCFS :

Every request gets a fair chance
No indefinite postponement

Disadvantages of FCFS :

Does not try to optimize seek time
May not provide the best possible service