jazz is known to run under Linux (xview and motif), Solaris (xview and motif), SunOS4.1.x (xview) and MS-Windows.
jazz was developed using wxwin (a free platform independend GUI library written by Juilian Smart).
Beside its own drivers for Linux (MPU-401, intelligent mode only) and MS-Windows (any midi card) jazz supports Hannu Savolainen's VoxWare drivers. These drivers are portable to other UNIXes and support many different midi cards.
Because of the client/server design of jazz's own driver, non-Linux Unix users are able to play/record by accessing a driver on a Linux machine via the network (TCP/IP).
Please note, that jazz does not support patch loading for soundcards at the moment. So you probably need a separate midi sound module unless you have a very intelligent soundcard, that simulates a GS MIDI equipment.