Scheduler Round-robin (RR) — divides execution into time slices (or quanta) with a given length . We maintain a queue of processes, but only execute each process for a maximum of time units at a time. If it’s still running, then we pre-empt and re-add to the back of the queue.
Performance depends on the quantum length Low ⇒ too much context switching (adds overhead, not useful) High ⇒ not enough switching. effectively reduces down to FCFS
RR has poor average waiting time when jobs have a similar length