Trackers are programs that generate music files called MODs. The MOD originated on the Amiga system, but quickly gained popularity, and now, software packages are available on almost every platform to compose and play these files. However, on the Macintosh, there are very few good trackers. A MOD file is significant, as it is a totally self-contained music file with a reasonable file size. It was intended originally as a compact way of storing background music for games and demonstration programs, but it has since grown to become a favorite file format for online music exchange.
Patterns are the equivalent of a score for the conductor.
Each pattern tells the computer what notes to play, how loud to play them, and just about everything else that can be done with a note. The samples are actual recordings of the musical instruments used to play the songs. Through a number of mathematical formulas, the computer can adjust the pitch and volume of the samples to make music. Composer PlayerPRO is more than just a tracker. It is a full-fledged composition tool.