It was distributed by Frog Peak Music, and runs with a very light memory footprint (~1 megabyte) on Macintosh and Amiga systems.
However, it has a high degree of built-in understanding of music performance practice, tuning systems, and score reading.
HMSL has been widely used by composers working in algorithmic composition for over twenty years.
In addition to the authors (who are also composers), HMSL has been used in pieces by Nick Didkovsky, The Hub, James Tenney, Tom Erbe, and Pauline Oliveros.
A Java port of HMSL was developed by Nick Didkovsky under the name JMSL, and is designed to interface to the JSyn API.