First-Come-First-Serve (FCFS)

1. First-Come-First-Serve FCFS

2. About FCFS Definition. It is the simplest CPU scheduling algorithm. With this algorithm, processes are assigned the CPU in the order they request it. Basically, there is a single queue of ready processes. Relative importance of jobs measured only by arrival time. The implementation of the FCFS policy is easily managed with a FIFO queue. When a process enters the ready queue, its PBC is linked onto the tail of the queue. The average waiting time under the FCFS policy, however, is often quite long.

3. Example of FCFS Example. Process AT BT WT RT TT P2 3 3 P4 4 2 3 3 5 P3 6 3 3 3 6 P1 2 4 1 1 5 P2 P1 P4 P3 0 2 3 4 6 7 9 AWT 1.75 ART 1.75 ATT 4.75 P2 P1 P4 P3

4. FCFS Contributor: Ledesma , Ruth Cavite City, Philippines