new find: an Intel MDS 800

From: Dave Mabry <>
Date: Tue Oct 26 19:24:41 2004

Welcome, Scott, to the Intel MDS Fraternity. Joe R., Jay West (your
list owner), and I are members that I know of. Joe will likely have
lots to say about your endeavour. I've been intending on (and slowly
performing) a backup of my MDS software, probably to some form of
optical storage for archive. Probably CD-R's.

What you are describing is what is called an Intel MDS Series II. The
MDS 800 didn't have an integral diskette drive or an internal crt
monitor. Yours is like mine, the "second generation" or Series II. The
internal diskette drive can be single density or double density
depending on whether it has the optional double density controller board
set or was controlled by the internal "I/O Controller" or IOC board.

If you have an external drive system, you likely have the double density
board-set for them. It can (but not necessarily) also control the
internal drive making it double density. In any case, all your drives
will be single SIDED.

Intel's OS was called ISIS-II, as you know. CP/M was also available for
it. I wrote a custom BIOS for CP/M so that you could access both
double- and single-density drives in one system. ISIS-II could do that
"out of the box" from Intel.

There is much more, but I'm tired now. I've been on the phone with Dick
Hof in Denmark working on his Intel iPDS project. But that's another story.

Enjoy your restoration! Let the brothers know of your progress!!!


Scott Stevens wrote:

> I recently acquired an exciting new (old) machine, an Intel MDS 800,
> known as the 'Blue Box.' It's the 1975-era 8080 based box that kicked
> off CP/M.
> My particular machine was intended as an 8051 ICE box, it has the 8051
> emulator pod and external PROM programmer.
> The system came complete with a big box of what appears to be complete
> docs and a lot of software on 8" disks. There are four or more
> different versions of IRIS, a disk labeled 'CPM' which I hope is a
> boot disk, and multiple versions of other Intel tools, including the
> targeted 8051 development tools.
> I paid a fair amount for this system, and am going to go slowly at
> bringing it up. It's been stored a long time and there's a troubling
> amount of surface rust on some of the screw heads and exposed
> hardware.
> I've popped it open and some of the ICs (mostly TTL) have corrosion on
> the leads. I have a few opening questions for others who have
> restored hardware in similar condition: should I remove the corrosion
> on IC leads, or do I run the risk of 'removing' the leads. The
> circuit boards look really good, so worst-case I will replace some of
> the chips.
> What is the opinion about this kind of servicing? The chips in
> question are all (so far as I have investigated) common 7400 series
> (some Schottky) TTL gates. Do people consider it as 'damaging' to the
> 'credentials' of a piece of classic hardware to replace chips with
> others with significantly different date codes?
> This is going to be a long term project for me, I fear, because I want
> to do it right. This machine has a built-in CRT display so I might be
> forced to do some (something I almost always refuse to do these days)
> video monitor troubleshooting.
> The machine has a built-in 8" floppy, which I assume is the
> low-density original, and an expansion case (third party) with two
> newer and higher density drives.
> Is there a source for new or NOS 8" floppies out there? One thing for
> certain that I'll be doing early after getting this machine up and
> running is a backup of all the media that came with it (a fair amount,
> probably 30-50 disks, many of which are Intel branded originals).
> Lots more questions and comments likely to come on this project.
> Scott
Received on Tue Oct 26 2004 - 19:24:41 BST

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