Vic Tracker is a music editor coded by Daniel Kahlin and runs natively on the Commodore VIC_20 released under the BSD-license.
From the website -- "VIC-TRACKER is a full-featured tracker-style music editor for the Commodore Vic-20. It includes a cross-compressor which produces compact assembly source code output suitable for inclusion in demos and games. As of version 2.0 VIC-TRACKER also supports Sync24/DIN-Sync making it easy to synchronize it to modern sequencers and electronic music hardware such as drum machines.
Note: To run VIC-TRACKER you need at least 16KB expansion memory, but compiled songs normally work on unexpanded machines."
Vic-Tracker 2.0
Windows Users: Use WinVICE (xvic.exe). First set Settings->VIC Settings->Use Full Blocks. Then autostart binary file 'victracker.prg' which is available via 'Contents of the Vic-20 Disk as a zip' on the above linked page.
To save true binary output, go to the Peripheral Settings, under Drive 8, uncheck 'Write .p00'. Vic Tracker will then write pure .VT binary (Vic Tracker file format) for you. This can then be used to be compiled into a stand-alone player with 'vtcomp' and saved and loaded to and from Vic Tracker.
Note: As of yet, vtcomp only works and compiles on *nix platforms. This also excludes MinGW and works partially in a Cygwin environment. As a whole, DOES NOT AT ALL work for or with Windows. :(