Csound was created by Barry Vercoe at the MIT Media Lab in 1985, and is a direct descendant of the original computer music language by Max Mathews at Bell Labs, Music 1. (Other systems in the “Music N” family include RTCmix, Pure Data, Max, and SuperCollider, among others).
Csound is now open source software (LGPL v2.1), and continues to be developed and maintained by musicians, programmers, and scientists around the world.
Although Csound was originally designed to be used in a non-interactive score driven context, nowadays it is mostly used for real-time performance, and even for live coding.
One of the main principles in Csound development is to guarantee backwards compatibility. You can still render a Csound piece from 1986 on the latest Csound release, and you should be able to render a piece written today with the latest Csound in 2036.
Csound home page (including Csound for other operating systems), with links to many more resources!
Csound on GitHub. Contribute code to Csound, read code, download code, and enter bug reports.
blue, a composition environment for Csound with extensive capabilities.
Cabbage, a Csound editor that can create VST plugins with custom interfaces.
Michael Gogins’ GitHub repository of computer music resources.