Int 17 Fn 91  - Alloy Ntnx, Mw386 - Get User Number And Current Printer    [N]

   AH = 91h
   AL = mode
       00h NTNX compatibility

       Return: CX = user number (00h = host)
           DX = currently selected printer number (00h-08h)
       01h MW386

       Return: CX = user number
           DX = physical dev number of currently selected printer
       02h MW386 v2+
       BX = logical device number
           00h-03h = LPT1-LPT4
           04h-07h = COM1-COM4

       Return: CX = user number
           DX = physical device number

Return: AL = status (see #0566)

See Also: AH=8Ch