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Comment by RealityVoid | Hacker News Reader

Hah, the first engineering job I had was on Ovation DCS doing power plant controls. That system traces the lineage to the WDPF systems.

Was the server you mention here the actual DCS? With the Motorola CPU's? Running vxworks? Pretty cool recognizing something niche that is still, vaguely familiar. :)

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The plant computer wasn't a DCS. I think it was a DEC. It gathered data from the control systems and instrumentation and had a bespoke in memory realtime-ish database. That database was then partially replicated down to the Sun workstations (code the 23 year old me wrote). Then the browser consumed that via a unix shared memory interface.

Was it perhaps DEC Baseway[1] system? It would arguably qualify as a form of DCS, with central VAX servers and running high level software, PDP-11 "shop floor" computers, which in turn talked with PLCs and related devices.

And additionally, TCP/IP was an optional layered product - either DEC's own UCX (Ultrix Communication eXtensions) or 3rd party

[1] https://bitsavers.org/pdf/dec/vax/vms/baseway/

I guess they didn't buy the optional network software.

I remember working with this engineer writing in the lower level TCPIP stack on the deck - maybe in Fortran? Anyway, he didn't understand why he wasn't getting all the data transmitted and while I was no expert in TCP/IP, I was already familiar with packets and maximum segment size (MSS). I remember being impressed that he banged out a network stack in a couple weeks.

Baseway, and various other industrial control systems that also ran on VMS and related, tended to either use DEC-suggested (DECnet) protocols or implemented custom Ethernet-layer ones

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