3. Round Robin

With the Round Robin scheduling algorithm, a queue is made holding all processes that are ready to run. When the first process is loaded into main memory, it is given a set amount of CPU time to use. If the process is completed during the allocated time then the next process in the queue is loaded immediately. However, if the process is not finished when its time expires, it is put at the back of the queue to wait for another turn.

Advantage of Round Robin

• It is simple to implement. Round Robin is a good algorithm if all the processes are more or less of similar priority and size.

Disadvantages of Round Robin

• It does not take into account how important a process is (its priority). A high priority process has to wait just as long as very low priority processes to get its turn in main memory.
• It does not consider that some processes are short and others long. If processes are very different in this way, it makes Round Robin an inefficient way to allocate time and resources.