Date   : Sat, 25 Apr 1981003:04:00-MST
From   : Max Diaz <MMD@SU-AI>
Subject: MTN and N* 

In N* port 0C0H is used to "arm the parity logic" in all RAM boards.
Actually MTN worked all right in terminal mode for a while after the
following patch:

    18-Apr-81  0058       Frank J. Wancho <FJW at MIT-MC>  MTN21 fix   
   Date: 18 April 1981 03:58-EST
   From: Frank J. Wancho <FJW at MIT-MC>
   To: MMD at SU-AI
   cc: FJW at MIT-MC

   ...Do the following patch to a copy of the MTN21.COM file:

   13A0 -> 00
   13A1 -> 00
   13B5 -> 00
   13B6 -> 00
   1669 -> 00
   166A -> 00

   This will start you up using BDOS console I/O instead of BIOS console
   I/O.  When you get to the part that offers you a choice of method of
   console I/O, you will only have two real choices, BDOS, or "Direct".

   The reason behind this is that your BIOS uses registers H and L
   without saving them - and MTN doesn't either.

HOWEVER I now have a parity problem in one of my boards, and am
wondering whether it was somehow damaged beacuse of that...(???)