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In [[computing]], '''input/output''' ('''I/O''', '''io''', '''IO''', etc.) is the communication between an information processing system (such as a [[computer]]) and the outside world, possibly a human or another information processing system.

== Description ==

I/O consists of:

* [[Input (computing)|Inputs]] are the signals or data received by the system.
* [[Output (computing)|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 ==

I/O devices are used by a [[User (computing)|human]] (or other system) to communicate with a [[computer]].

For instance, a [[keyboard]] or [[mouse]] is an input device for a computer, while [[Computer monitor|monitors]] and [[Printer|printers]] are output devices.

Devices for communication between computers, such as modems and network cards, typically perform both input and output operations.

== Duality of input/output relationship ==

The designation of a device as either input or output depends on perspective.

Mice and keyboards take physical movements that the human user outputs and convert them into input signals that a computer can understand; the output from these devices is the computer's input.

Similarly, printers and monitors take signals that a computer outputs as input, and they convert these signals into a representation that human users can understand.

== Human-computer interaction ==

From the human user's perspective, the process of reading or seeing these representations is receiving input

This type of interaction between computers and humans is studied in the field of [[human–computer interaction]].

== See also ==

* [[Control theory]]
* [[Feedback]]
* [[Input (computing)]]
* [[Output (computing)]]

== External links ==

* [http://en.wikipedia.org/wiki/Input/output Input/output] @ Wikipedia

[[Category:Computing]]