Round Robin

The Round Robin scheduling algorithm is a simple and efficient method used in operating systems to manage processes. It allocates a fixed time slice or "quantum" to each process in the queue, cycling through them repeatedly.

1. Processes Queue: All processes are placed in a queue.
2. Time Quantum: Each process is given a fixed amount of time (quantum) to execute.
3. Cycle Through: The scheduler cycles through the queue, giving each process its turn.
4. Preemption: If a process doesn't finish within its time slice, it is moved to the back of the queue.

Suppose we have three processes, P1, P2, and P3, with a time quantum of 3 units.

• Initial Queue: P1, P2, P3

• Execution Order:

  1. P1 executes for 3 units, then moves to the back.
  2. P2 executes for 3 units, then moves to the back.
  3. P3 executes for 3 units, then moves to the back.
  4. Cycle Repeats: Each process gets another turn if they haven't finished.

• Fairness: Each process gets an equal share of CPU time.
• Simplicity: Easy to implement and understand.

• Inefficiency: Time quantum needs to be carefully chosen; too small can lead to high overhead, too large can cause delays.

This approach ensures that all processes are treated equally and prevents any single process from monopolizing the CPU.