The Uniprocessor system can executes only one process at a time. When a process is executing on CPU the other will wait until the CPU is free. The Multiprogrammed operating system executes the process simultaneously to increases the uses of CPU. All the process requires the CPU cycle and I/O cycle to complete its execution. Suppose when a process executed on CPU and finishes its execution on CPU it is waiting for its I/O completion than in simple computer system the CPU will do nothing until the process completed its I/O request. During this the there is no useful working is there the other process which are waiting for CPU may sense the more waiting time. In multiprogramming, the operating system manages the process scheduling in which the processes which are ready to execute will kept in memory at one time. When the process is waiting for its I/O completion the operating system takes the CPU from that process and allocates the CPU to other process. By applying this scheme the utilization of CPU may be increased and the waiting time of the processes may be minimized. In this paper the researcher has presented the comparative analysis of classical CPU scheduling algorithms.
