ANS:D - I/O controller

I/O Controllers The controller is an electronic circuit board consisting of 3 parts An interface to connect to the system or I/O bus A set of registers An interface to connect to the device\'s cable.

I/O Controllers The processor controls and communicates with a peripheral device through an I/O controller. Some controllers operate both input & output of bits eg. Floppy disk controller Some controllers operate in one direction only eg. VDU controller - output Keyboard input controller - input.