Tracker is the generic term for a class of software music sequencers which, in their purest form, allow the user to arrange soun samples stepwise on a timeline across several monophonic channels. A tracker's interface is primarily numeric; notes are entered via the alphanumeric keys of the computer keyboard, while parameters, effects and so forth are entered in hexadecimal. A complete song consists of several small multi-channel patterns chained together via a master list.