Question # 3 I. What is the performance advantage in having device drivers and devices synchronize by means of device interrupts, rather than by polling (i.e., device driver keeps on polling the device to see if a specific event has occurred)? Under what circumstances can polling be advantageous over interrupts? II. Is it possible to use a DMA controller if the system does not support interrupts? Explain why. IV. The procedure ContextSwitch is called whenever there is a switch in context from a running program A to another program B. The procedure is a straightforward assembly language routine that saves and restores registers, and must be atomic. Something disastrous can happen if the routine ContextSwitch is not atomic. (a) Explain why ContextSwitch must be atomic, possibly with an example. (b) Explain how the atomicity can be achieved in practice