Running multiple programs simultaneously, that is multiprogramming, is an ideal technique for efficient use of such resources as the CPU, memory, data file sharing, and I/O devices. To schedule the CPU, for example, to maximize throughput while minimizing process delay time depends on the scheduling policies adopted. In class we discussed the FCFS, Priority, Round-Robin, and the SJF/SRTF policies. Briefly discuss each of these policies and argue how adding preemptive and non-preemptive criteria can further minimize process delays in some of the policies.