I/O Hardware

An I/O device, which is a type of peripheral device, communicates with the OS with the use of signals that are sent via wires or through the air (in wireless communication.)

The physical point at which the device connects to a computer, in case of a wired connection, is called a port.

A bus consists of a collection of wires and a set of rules and procedures, called a protocol, that dictate how signals should be sent via these wires. Signals come in a form of electrical voltages transmitted through the wires at a defined timing.

A computer uses a variety of buses, which differ by speed, voltage, throughput (workload), and connection methods.

The following illustration shows a typical bus structure in an OS.