Editing MOD (file format) (section)

== Format overview ==
A pattern is typically represented in a sequencer [[user interface]] as a table with one column per channel, thus having four columns – one for each Amiga hardware channel. Each column has 64 rows.

A cell in the table can cause one of several actions to happen on its column's channel when its row's time is reached:
* Start an instrument playing a new note in this channel at a given volume, possibly with a special effect applied on it
* Change the volume or special effect being applied to the current note
* Change pattern flow; jump to a specific song or pattern position or loop inside a pattern
* Do nothing; any existing note playing in this channel will continue to play

An instrument is a single sample along with an optional indication of which portion of the sample can be repeated to hold a sustained note.