8-bit ISA SCSI cards?

Jules Richardson julesrichardsonuk at yahoo.co.uk
Sat Apr 7 17:11:12 CDT 2007

Jim Leonard wrote:
>> Having CGA and VGA on the
>> same machine with dual monitors would be kind of interesting.
> It certainly would be, considering that it's impossible :-)   CGA and VGA
> both have adapter RAM at B800:0000.  

That reminds me...

Interrupt list (e.g. at http://www.cs.cmu.edu/~ralf/files.html) and scroll 
down a bit to "RBdualVGA":

   A set of programs for using two color SuperVGA cards in one PC. Includes
   a TSR for swapping between displays and blanking both screens when the
   system is not being used.

.. anyone know how the heck that works? I don't get how you can even boot a 
system with two video boards that are going to both expect to have ROM code 
and ports at the same addresses. Even if you could somehow disable the BIOS on 
one of them, there's still a bunch of conflicting port addresses to worry about.



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