> On Oct 15, 2025, at 7:14 PM, Doug Jackson via cctalk <[email protected]>
> wrote:
>
> Ethernet also got *way* more market traction, because it was
> infinitely more survivable.
>
> One of my early jobs was managing a Token Ring network, and we spent our
> days running around a 13 floor building, chasing machines where people had
> kicked connectors out of walls, just enough to stop data, but not enough to
> make the MAU do the self isolation. We had a piece of software called the
> Cabletron TR Manager - that monitored the ring for beaconing, and let us
> know the upstream node that detected the break. Then we would consult our
> *detailed* notes on what cards were installed where, so we could find the
> culprit that was broken. Without the notes, we would have had zero chance.
FDDI was somewhat better. It's not all that well known, but IBM (802.5) token
ring and FDDI have essentially nothing in common. At DEC when we were working
on its development we liked to say that the only things in common are "token"
and "ring". Actually, FDDI is in a sense an evolution of 802.4, of all things.
I also remember while there kicking around the notion that we could take the
FDDI signaling scheme (4b/5b code) and use it to send Ethernet packets. That
worked quite well and the rest is history...
>
> Heady days.
>
> I suggested to the network manager at the time that we could transition
> from TR to Ethernet (everything was wired with Cat3 Shielded cable - but he
> didn't want to, because "Ethernet had collisions" - that was when I
> discovered that everybody has limitations that something breaks their
> thinking. After a while I convinced him to transition one of the Cabletron
> cards to Ethernet, and do a test on a 32 workstation card - Suffice to say
> that those 32 machines never had an issue, and eventually, all 800 machines
> across two rings were transitioned to 100Mb Ethernet.
Around that time, IBM put out a marketing document that pretended to show why
token ring was better than Ethernet. The DECnet architecture group (where I
worked at the time) created a paragraph by paragraph rebuttal to that and
published it as a joint DEC/3Com document. I still have it: "The Digital/3Com
Guide to IBM document # GG22-9422-0" (DEC document EE-EA345-42-001). It
doesn't seem to be online, Google has never heard of it, nor the IBM document
it rebuts. As I recall, Bill Hawe was the lead author of that work; I wrote
some bits and pieces for it but I don't remember the details.
paul
