MIDAS is a multichannel digital sound and music system for MS-DOS, capable of playing an unlimited number of channels of digital sound on all supported platforms. It can play music modules, individual samples, and digital audio streams, in any combination. It supported MOD, XM and S3M files, and was developed by the group Sahara Surfers.

Source code (or a link to it) is included in the archive or on the production page. Note this doesn't necessarily mean the production is free software (FOSS).