When an i/o operation is called, it takes three steps to complete the operation: (1) prepare the i/o operation on the software level (defined in code block 4), (2) physical operations on the i/o device, and (3) complete the i/o operation on the software level (defined in code block 5, which is also interrupt handler). Please write down the simulation of program execution (complete the simulation at the point of “Physical operations of 1st i/o complete”. Clearly indicate the idle time on the CPU (if any) during the program execution.