First Come First Serves  Round Robin  The non-preemptive scheduling algorithm is first come, first served (FCFS).  The preemptive scheduling algorithm is Round Robin (RR).  FCFS has the least amount of overhead.  While RR has a small overhead because it must record the time elapsed and then switch the process, this causes an overhead.  In the time sharing system, FCFS is inconvenient to use.  It is primarily intended for the time sharing system and thus is simple to use.  In general, the average waiting time in the First Come First Served Scheduling Algorithm is not short.  The Round Robin Scheduling Algorithm has a low average waiting time.  The process is simply carried out in the order in which they arrive at FCFS.  In terms of processing, it is similar to FCFS, but it employs time quantum.