[TUHS] 3Bs (was A Talk on Early Unix)

Lyndon Nerenberg lyndon at orthanc.ca
Sun Jul 3 04:49:18 AEST 2016

> On Jul 2, 2016, at 9:00 AM, Larry McVoy <lm at mcvoy.com> wrote:
> Did anyone else ever use/own the 3B1?
> https://en.wikipedia.org/wiki/AT%26T_Unix_PC
> My buddy Rob got one and I think I did too or maybe just had a login
> on his.  Neat machines for their time.

Slick little machines.  Built by Convergent Technologies, running CTIX (their System V port).  Back in the day I was a Convergent reseller.  We never pushed the 7300, but we did shift a few MiniFrame and MightyFrame servers.

The MightyFrame was an impressive little beast.  We sold a couple that were supporting upwards of 40 terminals running database applications running under Mistress (later renamed Empress, in one of the earlier instances of political correctness invading the IT landscape).  CTIX incorporated the Berkeley network stack, and one of the systems ran an X.25 link to Datapac.

Perhaps the coolest aspect of the Convergent systems was the RS422 daisy-chained terminal interface.  The PT-100 and GT-100 terminals had loop-through RS422 interfaces, running at a couple of hundred Kb/s (I forget the exact speed).  You would daisy chain strings of terminals from the server, so 40 terminals only burned up four RS422 ports on the server side (in our deployments, at least).  Using these terminals was reminiscent of working on a 327x, since screen updates tended to come in bursts that looked just like block-mode updates.  The GT variant supported bit-mapped graphics - blazingly fast compared to something like a Tek 4010 running over an RS232 line.


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