Time required in programmed I/O = time required to check status of I/O + data transfer time.
as the operating speed of the device is 20MBPS
so to transfer 20B it will take 1 microsecond . (i.e the data transfer time)
and to check the status of the I/O i.e the flag sending time (2B flag – 0.1 microsecond)
thus the total time required is = (1+0.1) microsecond.
i.e 1.1 microsecond