[TUHS] C from 1980 binaries

[Marc Donner via TUHS]

UNIBUS - that’s a term I haven’t heard in tears.

At JPL as a young EE right out of college I designed a UNIBUS monitor that
my boss used in various installations.

That educated me about the bus, so years later I recognized that the
Motorola 68000 had essentially implemented it faithfully, with the
exception of making the Sync signal active-low instead of active-high (a
true blessing in TTL days).
=====
[My messages are from me, not from AI.]
exploringaimatters.com
nygeek.net

On Sun, Nov 1, 2026 at 10:16 PM Clem Cole via TUHS <tuhs at tuhs.org> wrote:

> Indeed. Great guy.  The Unix community stop solidly on his shoulders for
> many years.  I haven't spoken to him in years.  After the CalData lawsuit
> and when he created Able, he said he'd only make peripherals and swore off
> CPUs.   His DMAX (DH/DM) became pretty much required if you were part of
> USENET, particularly if you had Telebit Modems.   He made a lots money
> selling them to the Unix community.  He knew it was very appreciative.   He
> used to come to USENIX conferences regularly and warn us to watch out about
> Unibus implementations from a number of the 3rd party vendors.  Which with
> him being one himself, was humorous.
>
> Besides his famous replacements for DEC's terminal mux products, he also
> made bus repeaters and caches.  At an early USENIX shortly after he had
> released a cache for the 11/34, a couple of us were at dinner and I was
> sitting next to him.  In those days, besides being a Unix hacker,  I was
> also designing hardware and had just designed the MMU for the Tek
> Magnolia.  So I asked Ken, since he was moving the Unibus memory down
> stream of his cache, why couldn't put a new MMU in it, and basically NOP
> the DEC MMU, but split 22-bit adresses out the other end.  We sketched
> something and he said he would think about it.
>
> About a month or two later he calls me and asked if I wanted to try what he
> just finished.  They ended up calling it the "Enable" and allowed 11/40 and
> 11/45 class systems to address up to 4M like the 11/70.  If you google it,
> you'll find Noel's page on Gunkies.  Noel also has links to the paper I
> wrote about it, as well as scan of the prepublication user manual and a
> sketch of the registers it supported whicj I had sent Noel a few years
> ago.  The code is actually still 2.11BSD but disabled since it's no longer
> relevant as 2.11 pretty much requires an 11/70 and boards are hard to find
> these days.
>
> BTW, a few years later Mike O'Dell and I tried to get him to make a version
> on the DMAX for the ISA or EISA bus.   We also suggested making an Ethernet
> version with a 68000 in it and we would wrote the code for it, since
> putting serial ports, particularly ones with modems, on PC hardware was
> such a losing proposition. But Ken told us that margins for PC peripherals
> was too low for him make any money on it.
>
> Soon there after we all bought Livingston boxes to do the job.  I always
> felt bad, as I think would have done a great job if could have figured it
> out.
>
> BTW: he did eventually break his rule about CPUs slightly. He ended up
> creating a QBUS 68010 CPU board that he showed me when I visited him in
> Irvine at some point.  I don't know how well it sold and lost track of him
> after that as I left the Vax/PDP-11 world and when I returned to it to work
> on Alpha, I never ran into him.
>
>
> Sent from a handheld expect more typos than usual
>
> On Sun, Nov 1, 2026 at 9:11 PM Jon Forrest via TUHS <tuhs at tuhs.org> wrote:
>
> >
> >
> > On 11/1/26 5:13 PM, Clem Cole via TUHS wrote:
> >
> > > At the time, WD was working on the chipset, and DEC had won the lawsuit
> > it
> > > filed against California Data Processors (*a.k.a.* CalData). The
> results
> > of
> > > that lawsuit were fresh in the eyes of the team at WD  [Ken O'Mohundro
> > and
> > > Fred Cox's firm cloned a number of different ISAs but chose the UNIBUS,
> > > which got them in trouble.  O'Mohundro had famously run the complete
> > 11//40
> > > diagnostics suite for Ken Olson at the National Computer show in
> > CalData's
> > > booth].
> > Ken O'Mohundro - there's a name I haven't heard in a while. In the early
> > 1980s I ran the Santa Barbara VMS Users Group. At the time, there were a
> > few vendors who were starting to make DEC-compatible peripherals, such
> > as memory, and disk/communication/network controllers. One of the
> > vendors was Able, in Orange County, CA. Somehow Ken contacted me to
> > ask if he could come talk to our users group about DEC stuff. Ken
> > was a self-described stutterer who enjoyed addressing groups of
> > people as a form of speech therapy. So, he came all the way up
> > to Santa Barbara from Irvine and gave a nice presentation. IIRC,
> > Able Computer paid for lunch for everyone.
> >
> > He was a very nice guy.
> >
> > Cordially,
> > Jon Forrest
> >
> >
>