How does a program execution take place in multiprogramming?

While the processor is dealing with a number of programs, the sequence with which programs are implemented will depend on their relative priority and on whether they are waiting for I/O. When a program former interrupted and control transfers to an interrupt handler, formerly the interrupt routine has completed, control may possibly not immediately be returned to the user program that was in implementation at the time. In its place, control may perhaps pass to some other pending program with a higher priority. Ultimately, when it has the highest priority, the user program so as interrupted will be resumed