High Quality Content by WIKIPEDIA articles! The Hierarchical Music Specification Language (HMSL) is a music programming language written in the 1980s by Larry Polansky, Phil Burk, and David Rosenboom at Mills College. Written on top of Forth, it allowed for the creation of real-time interactive music performance systems, algorithmic composition software, and any other kind of program that requires a high degree of musical informatics. It was distributed by Frog Peak Music, and runs with a very light memory footprint (~1 megabyte) on Macintosh and Amiga systems.