According to a website capture from 2004, jmusic is "a 100% midi-controlable realtime softsynth with size and speed optimized player...ready to link it into your 64k intro.".

A file named jmusic10.zip, marked with "coming soon", is linked on the website, yet not preserved on Wayback Machine. According to the DPS website capture, development began in March 1996, yet was "still going on" in 2004, so it is unclear which versions were released, if at all.