Intellec MDS questions

From: Steve Thatcher <>
Date: Sun Jan 30 12:48:16 2005

comments below...

At 01:35 PM 01/30/2005, you wrote:
>Hey all,
>Thanks for all the background and help on the Altair project. I'll be
>taking some pics of the pile for a 'before and after' set. Hopefully there
>will be an after worth mentioning ;-)
>Now on to Intel / Intellec MDS systems. I've got one that is alternately
>described as an MDS225 or and MDS800. IIRC, the dual-disk unit is marked
>MDS800, (blue in color) and the main chassis is marked MDS225 (white in
>color, has a monitor, kb, and a series of pushbuttons with LED indicators).

if the drive cabinet has the drives vertically then it was originally
attached to a MDS800 system. The Series II machines (225, etc) had dual
drive cabinets that had the drives horizontal.

>Information on these units is pretty sparse on the web; multiple google
>searches have yielded little more than years of manufacture, and some
>price info.
>One question that should amuse the more veteran members of classiccmp is
>this: What exactly is meant by "Microcomputer Development System"? It's
>like that old joke about "Repairing Robots".. Are they referring to the
>process of repairing a robot, or to robots that perform repairs?
>Is the MDS a system for developing microcomputers, or is it a
>microcomputer that is used for other forms of hardware / software
>development, or a little of both? I'm getting the feeling that the latter
>might be the case.

actually, it is neither of the two you suggested. The intent behind the MDS
machine was to use them for the development of microcomputer systems from
both a hardware and software standpoint (it was not to develop
microcomputers). The term "Microcomputer" in Intel's use referred to the
hardware platform that was being developed to do whatever job the hardware
was supposed to do. I developed hardware based on both the 8080 and 8085. I
developed the code on the MDS and used the ICE (in-circuit emulator) for
both hardware and software development and debug.

>Secondly, what kind of operating system, applications, etc can one of the
>MDS units run? I'm told that it is an ISIS based system, but I really
>don't know much about ISIS. I assume it's a disk operating system, but
>beyond that I'm clueless. I'd like to think that there is some
>general-purpose OS I could run on it, play some wumpus, trek or life,
>amortize my mortgage, or maybe fire up a terminal emulator and get into
>the BBS scene.

ISIS was developed as what I call a professional operating system rather
than CP/M which was a hobby OS. ISIS ran only on Intel systems (okay,
except for the N* I had it running on) and was not adaptable to other
platforms (uinlike CP/M). ISIS came with an 8080 assembler, linker,
librarian, as well as PL/M (a high level language, but lower than C). There
are copies of CP/M that run on the MDS. Kildall originally developed CP/M
written in PL/M on a MDS800 computer.
Received on Sun Jan 30 2005 - 12:48:16 GMT

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