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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 da
by intrasight 1mo ago
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.
- p_l 1mo agoWas 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/ https://bitsavers.org/pdf/dec/vax/vms/baseway/
- intrasight 1mo agoI 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.
- p_l 1mo agoBaseway, 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