ModPlay

ModPlay was the first Protracker Module player that supported the PC speaker and soundcards other than the SoundBlaster. It let you play Amiga soundtracker, noisetracker, and protracker module files on a 10MHz 286 system or better. Modplay was written entirely in assembler code, running to over 11,000 lines of source code taking around 400 hours to produce. Modplay came with details and circuit diagrams for building parallel port DAC devices, amplifiers, and more. Although I didn't give out the source code, it was a completely freely distributable program.