CONCEPT - First Come First Serve (FCFS)

Algorithm


First Come First Serve(FCFS)

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.Let us understand this with the help of an example.

    Advantages:

  • Every request gets a fair chance
  • No indefinite postponement

    • Disadvantages:

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

Example:

Suppose the order of request is- (82,170,43,140,24,16,190)
And current position of Read/Write head is : 50

So, total seek time: = (82-50)+(170-82)+(170-43)+(140-43)+(140-24)+(24-16)+(190-16) = 642