(1) What is meant by pre-emptive scheduling? (4 marks) (2) Describe the following scheduling algorithms (9 marks) Non Pre-Emptive, First Come, First Serve Round Robin Shortest Job First (2) Given the following processes and burst times Process P P P3 PA Ps P6 P Burst Time 13 5 23 3 31 3 14 Calculate the average wait time when each of the above scheduling algorithms is used? Assume that a quantum of 6 is being used. (12 marks)