One more reason for keeping those old legacy computers around...
My old Atari Mega ST4? Bulletproof sys-ex (and built-in MIDI!)
My old serial port Mac clone (Starmax) and serial MIDI interface? Bulletproof sys-ex.
My current old Mac (Quicksilver733

) and Midex3 MIDI interface? Bulletproof sys-ex in OS9 and OSX Panther.
Newer ain't necessarily better...
