Scheduling

First In, First Out (FIFO)

• Most basic algorithm
• Also know as First Come, First Served (FCFS)
• Simple to implement
• Not a great performer

Perfect

$T\mathrm{\_}turnaround=\frac{10+10+10}{3}=10$

Bad Performance

$T\mathrm{\_}turnaround=\frac{100+110+120}{3}=110$

Shortest Job First (SJF)

$T\mathrm{\_}turnaround=\frac{10+20+120}{3}=50$

Round Robin

The basic idea is simple: instead of running jobs to completion, RR runs a job for a time slice (sometimes called a scheduling quantum) and then switches to the next job in the run queue

Advanced Algorithms

All the algorithms discussed are fairly simple and modern operating systems use more advanced data structures such as a multi-level feedback queue to further improve performance!