Question

In a programmed input/output(PIO) __________

(a) the CPU uses polling to watch the control bit constantly, looping to see if a device is ready

(b) the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available

(c) the CPU receives an interrupt when the device is ready for the next byte

(d) the CPU runs a user written code and does accordingly

I got this question during an internship interview.

My question is from Process Structures in chapter Distributed Communication of Operating System

Answer 1

The correct choice is (a) the CPU uses polling to watch the control bit constantly, looping to see if a device is ready

To explain I would say: None.