Input/output

I/O is a general name for any operation in which your code interacts with the outside world. There are many things that count as I/O, and there can be plenty of I/O that is internal to your software, especially if your application has a distributed architecture.

Note

The recent rise in popularity of the .io Top Level Domain (TLD) can be partly attributed to standing for I/O, but that is not its real meaning. As is the case for some other TLDs, it is actually a country code. Other examples include .ly for Libya and .tv for Tuvalu (which, like the neighboring Kiribati, may soon be submerged beneath the Pacific Ocean due to climate change).

The TLD .io is intended for the British Indian Ocean Territory (BIOT), a collection of tiny but strategic islands with a shameful history. The .io TLD is therefore controlled by a UK-based registry. BIOT is nothing more than a military base, and also happens to be a hop on the proposed AWE fiber optic cable between Australia and Djibouti.

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