MPX-16 census

Scott Stevens chenmel at
Sun Oct 9 09:46:14 CDT 2005

On Sat, 8 Oct 2005 06:50:21 -0700 (PDT)
Chris M <chrism3667 at> wrote:

> a scholar and a gentleman. I even considered building
> my own, though not sure if MM made the artwork
> available. Was put off by the fact that the board has
> 7 layers according to the article. If anyone is
> knowledgeable enough of pcb production - is it
> possible to make a 7 layer board w/o special
> equipment/materials? Why did it even need 7 layers?
> How many layers were did the IBM PC mobo have? I know
> for a fact that the RE robot puter (80188) mobo had 2
> sides (top and bottom, no sandwich).
> --- cctech-bounces at

I remember wanting to build one, too.  Now I have one.  

I wonder if there would be enough interest and/or resources to produce a
new batch of the boards for it?  It would be an expensive undertaking. 
For one-off purposes, I suspect it would be cheaper and less work to
just make a wirewrap version.  It wouldn't be that hard to do a good job
at that, using the existing layout from the PC board version as a
starting point, and laying in a good grounding/power infrastructure
before wire-wrapping the data paths.  There aren't a lot of 'unobtanium'
chips in the MPX-16 design, and it is a nearly completely 'published'
work, the schematics spread over three Circuit Cellar columns in Byte,
also reprinted in Volume 4 of'Ciarcia's Circuit Cellar' published by

The MPX-16 fills an interesting gap in the history of hobbyist
computing.  In a sense, it was a 'stab' at keeping the personal computer
a hobbyist enterprise.  By publishing a 'kit' version with hobbyist
tweaks and differences (the MPX-16 has dip-switch settings to select 8"
floppies, for example) Ciarcia was trying to 'keep it real' for the
people accustomed to 'writing code with solder' as he once put it. 
Another list member described it as 'the Circuit Cellar segment that
marked the end of  
BYTE as a non PC hardware/software magazine.' (woodelf)  Looking at all
the cool hardware projects that used to get published in Byte, I have to
agree.  MicroMint didn't cease to exist, of course, and Ciarcia's
magazine Circuit Cellar INK has had a long run of truly great projects
and articles over the years.

Some news about my machine and the particular collection of diskettes
that came with it.  There are many different copies of CP/M, it appears
whomever these disks belonged to either was involved in the porting to
the MPX-16 or just tracked it very closely.  I brought the machine up
yesterday for the first time and it works great.  Dual TM-100 disk
drives in the 'official' case makes it a most complete system.  It boots
using the serial console as I haven't yet tried it with a video card.  I
might never 'bring it to that point' as that just transforms it into a
kinda-PC/XT system.

I booted CP/M-86 on it successfully from the disk set marked 'Version
2.1.'  There is .A86 source code for most of the CP/M on the three
diskette set.  Not a lot of third party apps in the 69 diskettes in the
collection, but then some of the disks are marked 'BIOS source code' and
other low level system things.  Seems the original owner was definitely
a Systems Programmer.

Then I thought I would try DOS so I took my stock (actually an original)
IBM PC-DOS 1.0 diskette and it booted perfectly.  It boots much faster
than an IBM-PC, probably because I didn't observe it doing any kind of a
memory check.  I duplicated the PC-DOS 1.0 diskette (shouldn't have even
_needed_ to use the original in this day and age) and then also booted
PC-DOS 1.1.  1.1 boots fine, too.  Later versions wouldn't work,
obviously because they require double sided diskettes.  (back in the day
I upgraded my father's PC-1 system to double sided diskettes when he
wanted to upgrade to DOS 2.1)

The biggest limitation in running DOS on the machine is that any app
that writes directly to video I/O or does any Video functionality at all
won't work.  But it's mostly born to be a CP/M-86 system in any event. 
There aren't a lot of apps on the large collection of disks.  There is
some sort of a word processor, but when I brought it up it was obviously
designed for a particular terminal as it flooded the screen with a mess
and I couldn't get out of it at all without rebooting the machine. 
There are some other small apps on one diskette with source code,
including a term emulator and what appears to be a low-level Diskette
editing utility.

All in all, the 69 diskette collection is a real jumble of things. 
There are multiple copies of most of everything, including MicroMint
originals and 'working' copies.  Several of the MicroMint originals have
'master' written where there should be a serial number penned in by hand
on the label.  One diskette says 'CP/M-86 for the Micromint MPX-16
2/17/83' all written out in longhand like it might be the very first
release and/or even the original master.  It's an exciting collection of
diskettes and after some organizing the images will be shared.

There are also a few 'PC' related diskettes.  A preliminary demo version
(apparently bundled with PC World Magazine) of Microsoft Word on an
official Microsoft diskette.  It works, with a 'demo' splash screen, on
a modern PC.  There is a disk marked 'CP/M-86 1.0 for the IBM-PC' that
also boots properly on a modern PC (one of my ubiquetous Dell Optiplex
Pentium 3 machines- the one now with a 5-1/4" disk)  There is a diskette
marked PC-DOS that boots to a diagnostic menu and won't proceed as I
don't have the 'diagnostic disk' to insert.

Well, enough about the MPX-16 and it's bundle of diskettes.

> <chenmel at> wrote:
> > On Fri, 7 Oct 2005 07:29:40 -0700 (PDT)
> > Chris M <chrism3667 at> wrote:
> > 
> > > dont have one, but want one. I hope youll make
> disk
> > > images available.
> > 
> > I certainly will.  A list member has extended a warm
> welcome to the idea
> > of me imaging my disks and putting them on his site.
>  More to follow
> > when they're all imaged and online.
> > 
> > > --- cctech-bounces at
> > > <chenmel at> wrote:
> > > > Does anybody else on the list have an MPX-16
> system?
> > >  I recently
> > > > acquired one from a list member and am wondering
> how
> > > many of these
> > > > systems still exist.  I have a large
> (relatively)
> > > collection of
> > > > diskettes with mine.
> > > > 
> > > > The MPX-16, for those not familiar with it, was
> > > published as a project
> > > > in Steve Ciarcia's 'Circuit Cellar' column in
> Byte
> > > magazine.  It was a
> > > > three part 'construction' article and the
> machine
> > > was sold by MicroMint
> > > > for a time.  What I've heard is that about 500
> > > machines in total were
> > > > produced.
> > > > 
> > > > It's an early 'IBM Compatible' in that they
> designed
> > > it to be similar to
> > > > the PC, but only to a certain degree.  It uses a
> > > serial console rather
> > > > than keyboard/display adapter, and it runs
> CP/M-86
> > > and supposedly MS-DOS
> > > > though I don't have DOS diskettes for mine.  It
> has
> > > ISA slots and a
> > > > similar architecture to the IBM-PC, coming out
> of
> > > that early era before
> > > > there were PC clones from the likes of Compaq.
> > > > 
> > > > I'm curious of how many other MPX-16 systems
> have
> > > survived to today. 
> > > > There isn't a lot about it online.  I can share
> what
> > > information I have,
> > > > as I have manuals and docs with my system.  I'm
> > > interested in hearing
> > > > from other people with this machine.
> > > > 
> > > > Scott
> > > 
> > > 
> > > 
> > > 		
> > > __________________________________ 
> > > Yahoo! Mail - PC Magazine Editors' Choice 2005 
> > >
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