pdp8/a boards

From: Christian Fandt <cfandt_at_netsync.net>
Date: Wed Oct 6 08:03:28 1999

Upon the date 10:13 PM 10/5/99 +0100, Tony Duell said something like:
>>
>> Ok, is there some trick to identifing pdp8/a quad height boards? Or maybe
>> most of these boards are not standard DEC issue... I have a lot of boards
>> that have wierd markings on the green or grey handles, all have VG DS on
>> two sets of handles, but one of those is covered with a round sticker with
>
>A guess, based on some boards in my collection...
>
>VG DS is Vacuum Generators Data Systems or something like that. They're a
>company who make (made?) various lab instruments (mass spectrometers,
>etc). And the cards are interfaces (ADC, DAC, custom parallel interfaces,
>etc) between the PDP8 omnibus (I think I've seen Unibus ones as well) and
>the instument.

I can believe this Tony as a European vacuum coating equipment company
named Balzers AG (from Liechtenstein) once used PDP-8 systems as a process
controller. Therefore I feel it would be quite logical that VG would have
made partial pressure analyzers, thin film deposition controllers, gas
controllers, etc which interfaced directly to Omnibus. They would have sold
them for a much more economical price. If any of you had seen the prices
Balzers charged for the same type of equipment, you'd probably concur.

I understand even today Balzers uses the old DEC Falcon PDP-11 boards in
their BPU-430 Process Control system. The previous BPU-340 controller used
a custom crate with four Qbus slots and an M8089 (PDP-11/23) of some
variety I can't presently recall and a _verrrry_ limited subset of RT-11 of
some unknown version.

As an aside to illustrate the high cost of getting anything out of Balzers
there were several rather minor bugs in the display text of the user
interface of that vacuum deposition system used at my ex-employer. Only one
moderately significant functional bug and just a couple of valve labels
swapped around and the version number not updated (it still said "TEST" in
the software program version number at the main screen heading of the
application) and one or two other minor display things. I wanted to have
those fixed as the operators got a bit confused with the labels swapped
around and a large gate valve could be opened in Service Mode while a
loadlock chamber was still under vacuum -which is Not Good. Balzers quoted
me approximately US$7000 (!) just to clean up their mistakes. There were
two specially modified vacuum coaters made from a basic system they had
sold to IBM in the late 80's/early 90's and they would have certainly not
have lost any money on just fixing those minor problems especially when
each of those modified coaters cost over DM2 million (US$1.2 mil) when new.
One is at the parent company in Germany and the other in Jamestown.

At $7000, Balzers USA and I figure this was Balzers AG's way to tell me to
bug off and don't bother them with old software problems.

I used a VG Instruments partial pressure analyzer back in the 80's which is
likely the same company under the Vacuum Generators marquis as VG Data Systems.

>It may well be possible (given schematics, which would take a couple of
>afternoons to trace out) to use them for other interfacing tasks. Fancy a
>bit of control/data logging ? ;-)

I agree. If I could see some interface connectors to external
sensors/probes or markings, etc. it could give me more hints as to what its
original use was. Larry, any close-up photos online?

Regards, Chris
-- --
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA cfandt_at_netsync.net
        Member of Antique Wireless Association
        URL: http://www.antiquewireless.org/
Received on Wed Oct 06 1999 - 08:03:28 BST

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