On 03/03/2013 02:33 AM, Jens M Andreasen wrote:
  I have obviously been a bit out of the loop not
noticing this before,
 but anyway, the Steem Source was released under GPL on July 01, 2011.
 It's got MIDI in it which is why this is interesting for us. There are
 lots of editors for antique synths out there (or for their emulations)
 as well as a bunch of funny auto-composers  (M, Ludvig) and other
 MIDI-toys. The original Steinberg Cubase Light is still freeware if you
 need a 16-track sequencer.
 
http://www.atari-forum.com/viewtopic.php?f=5&t=21263
 
Apps are available at Tim's Atari MIDI World:
http://tamw.atari-users.net/timidi.htm
A great resource from the late Tim Conrardy.
Almost everything I've tried from TAMW worked with Xsteem and the Hatari
emulator.
Best,
dp