thanks for all the info so far

A hint for all noobs trying to get this working: the current state of emulation in MESS indicates the "DEC Rainbow 100" emu is "non working" and "without sound".

All you will see is a black screen with diagnostic error 18 (and probably error 16). This indicates a problem with the Z80 subsystem (CRC error).

I refer to the compiled versions of 'messui145u7b' and 'mess_winui_32bit_r14889' available on the net.

Guess the board logic is incomplete / not implemented yet...

Hope we will se some progress on this matter... cool

In the meantime, one might try the RBE - Rainbow emulator for DOS ( http://rainbow-100.com/archives/73/ ). Although i doubt it's very compatible.

  The following Rainbow firmware (int 18H) functions are emulated by

               Function 00H,    Console output
               Function 02H,    Level 2 Console in
               Function 04H,    Level 2 Console Status
               Function 06H,    Level 1 Console in
               Function 08H,    Disable Cursor
               Function 0AH,    Enable Cursor
               Function 14H,    Write characters and attributes to screen
               Function 1EH,    Ring the keyboard bell

          Calls for any of the other functions available through int 18H are ignored.

( taken from RBE.DOC )

RBE requires an ANSI driver