In computing, input/output, or I/O, refers to the communication between an information processing system (such as a computer), and the outside world ? possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it. The term can also be used as part of an action; to "perform I/O" is to perform an input or output operation. I/O devices are used by a person (or other system) to communicate with a co