CP/M for IBM Displaywriter

Nigel Williams nw at retrocomputingtasmania.com
Sun May 15 00:34:02 CDT 2016

On Sun, May 15, 2016 at 2:43 PM, Ali <cctalk at ibm51xx.net> wrote:
> I've seen references to a CP/M port for the IBM Displaywriter in magazines of the era. Has anyone ever seen this beast in real life? Better yet anyone have a copy of it?

Thanks for the reminder, I'd been meaning to send an email here and
elsewhere calling out the re-discovery of "CP/M-86" for the IBM 6580

I understand that CP/M-86 was intended to be an actual product for the
IBM Displaywriter, but I've not found an IBM product code for it, and
I don't recall during my searches that I found anyone who actually
used it as a released product. It could be that IBM asked Digitial
Research to do the demonstration port so they could assess whether
there was any interest in it. I contacted one of the Phoenix BIOS team
who had also done a port of MS-DOS to Displaywriter and was assured
this never became a released product.

As it happens, the demonstration port of "CP/M-86" for the IBM
Displaywriter has been hiding in plain sight for over 10-years. I have
been looking for it for at least 5+ years ever since I became
interested in Displaywriter and managed to acquire one in Australia.
>From time to time I trawl back through the usenet archives attempting
to track down details of the Displaywriter and came across an
interesting comment by the people who recovered some of the original
DRI disks. This recovery resulted in these diskettes being imaged back
in 2005. The comment made a reference to a couple of diskettes labeled
(DRI) "concurrent CP/M 86 DW Demo, Data Drive B (right" - it was
speculated as to what they were but it seems no one examined them
further at the time. I was intrigued by the initials DW and downloaded
them and took a look, it was clear they were for the Displaywriter and
they booted fine once I copied them onto 2D media (I initially tried
the image as Type 1 diskettes but that didn't work).

I'm double-quoting CP/M-86 deliberately since the diskette image on
the Internet is actually of a demonstration port of something more
than merely CP/M-86, it is some hybrid (or transitional) MP/M-86 and
Concurrent CP/M-86, I have some screenshots here of it running:


DRI was I think developing CCP/M-86 in late 1982, and had derived it
from the MP/M-86 codebase and this demonstration port seems to be of
this alpha or beta code for CCP/M-86.

Other than the keyboard, diskettes and the screen, I've not been able
to discover the extent of driver support for Displaywriter hardware
(comms, printer). The IBM Displaywriter is a complex machine with
several (factory) configuration options, and it was not originally
designed to host multiple operating systems or to be (as easily)
re-configurable like the IBM 5150 PC. You purchased the Displaywriter
with a specific set of options. I doubt the demonstration CP/M-86 port
can do much more than be a dumb terminal to CCP/M-86.

Anyhow, you want to look here:


under this section:

NEW 04/10/2005 Miscellaneous DRI disks

You'll need to use Dave Dunfield's utilities or similar to image the
diskettes onto the 8-inch format.

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