Commodore PET
PetSynth is an open-source music software for the Commodore PET computer, created in 2007 by Chiron Bramberger. It is noteworthy for being the only keyboard playable synthesizer for the Commodore PET that supports MIDI, stereo sound, and is released under a GPL license. It has been featured in print and web publications such as Return Magazin, "TPUG Magazine", Commodore Free Magazine, Retrothing, and MatrixSynth.