ROM dumps of Intel MDS-2 IOC

Dave Mabry dmabry at
Sun May 17 19:06:09 CDT 2015

F.Ulivi wrote on 2/17/2015 9:19 AM:
> Hi everyone,
> I'm looking for the images of ROMs installed on the IOC (I/O controller)
> board of Intel MDS-2 development systems. In particular I'm looking for
> the content of the character generator ROM (A19-2708) and of firmware
> ROMs (A50 to A53-4x2716). So far I had no success in googling them.
> My goal would be to contribute a good emulation of MDS systems to MESS,
> especially for what regards the look of the video terminal. Well, this
> is the plan, when "real-life" is not inteferring too much...
> Thanks a lot.
> -- F.Ulivi

I know I'm kind of late into this discussion, but I just took a look at 
what I have and perhaps I can help.

I have the character generator rom code from an IOC.  Not sure if there 
were any changes to it over the revisions of the IOC, but I don't think 
so.  My copy should be good.

As for the firmware, there were many versions.  At one point Intel 
released an upgrade package called the iMDX-511.  That added 
cursor-addressbility on the integral CRT, a function key on the keyboard 
(replaced the RPT (repeat) key), some shortcut key sequences, improved 
speed, and other things I can't remember.  It was a standard part of the 
Series-II at some point, about the same time the white one became available.

I have all that rom code.  I even took a swipe at disassembling it to 
try to understand it.  That was never finished, but I did make some 

If the 8741/8041 chip on the IOC was called the PIO (Parallel I/O) then 
I have that rom code too.  I have a document that says the 8041 is 
indeed the PIO.

The iMDX-511 also included an enhancement to the keyboard processor.  I 
have that rom code as well.

I'm really sorry I didn't look into this sooner as it may have saved a 
lot of discussion on this list.

In any case, I can create a zip file of what I have an email it to 
anyone interested.

Just email me a good email address for you and I send it out.


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