ProTracker

ProTracker shipped in 1990 and built on NoiseTracker and Karsten Obarski's Soundtracker into the tool that became standard for MOD music on the Amiga. A tune is written as patterns in a grid: four columns, one per hardware channel, where each row sets a note, a sample and an effect command. The interface was spartan and keyboard-driven, but once learned you could write a track anywhere.

The program's four-channel limit and its exact timing defined the sound of early tracker music, and modern trackers still imitate its behaviour to sound "right". For many demoscene musicians ProTracker was the first and last tool they ever needed.