FCFS is optimal average waiting time

FCFS scheduling is a nonpreemptive algorithm

Convoy effect leads to

Associate with each process the length of its next CPU burst

is used to break a tie if the next CPU bursts of two processes are the same

SJF is optimal — gives minimum average waiting time for a given set of processes

Can be done by using the length of previous CPU bursts, using exponential averaging

Shortest-remaining-time-first is nonpreemptive

τ(n+1)

priority scheduling is

the problem of priority scheduling is Starvation as low priority processes may never execute

The performance of the RR depends heavily on the size of q (time quantum)

system consists of a finite number of resources to be distributed among a number of competing
processes

Each process utilizes a resource as follows: request, use, release

a resource can be released only voluntarily by the process holding it, after that process has completed its task

a process holding at least one resource is waiting to acquire additional resources held by other processes

only one process at a time can use a resource