9 Feb
2020
9 Feb
'20
5:48 a.m.
Took this to coff since it's really hardware and non-Unix...
On 2/8/20 1:59 PM, Noel Chiappa wrote:
My old Field Service memory is DEC never really went after Unibus
interfaces and the spec was open. It was connections to the big old
Massbus for things like tapes and disks that they kept closed and used
patent protection on along with the SBI and the later Vax BI bus. DEC
was the only maker of the BIIC chip from the VAXBI and the wouldn't sell
it to competitors...
Braegan (may be a spelling error) made interfaces to connect Calcomp
hard disks to the PDP11's on a Massbus. IIRC they were shut down hard
with legal action. I had a customer with a Unisys (formerly RCA)
Spectra 70 system that had Braegan Calcomp drives with an Eatontown, NJ
based Diva Disk controller. My tech school instructor pre-DEC career
worked for Diva Disk as an engineer.
Systems Industries, later (EMC), cloned the Massbus Adapter on the SBI
Bus and didn't directly share the bus or controller with DEC sold disk
drives so the SI-9400 showed up on DEC 11/780's (and I think they had an
11/70 controller as well. DEC, IIRC went after them about them using
the SBI backplane interconnect.
A Google search showed up this note about EMC Memory boards in Vaxes but
also mentions DEC patent suits against people who used the Massbus. I
don't remember that on Unibus devices like the controllers from Emulex
and others. (Until they tried to deal with the Vax BI bus -- a DEC chip
only or the MSCP disk subsystems.)
Like you say, different time, different business model. Many inside DEC
wanted them to OEM Sell Vax chips like they did PDP11 LSI/F11/J11
chips. There are a number of DECcies who feel that attitude came over
with the influx of IBM'ers and others who came to DEC in the Vax period
to sell into the Data Centers.
They were really protecting the "family-er-crown jewels" back then to
the company's detriment.
Old Computerworld and Datamation adverts along with PR releases are what
I find when searching, unfortunately. Here's a suit against EMC --
which cloned DEC memory products and interfaced to the SBI 11/78x bus.
https://books.google.com/books?id=0sNDKMzgG8gC&pg=RA1-PA70&dq=DEC%2…
Along with the DIVA Computroller V there's another picture at the left
of the page with a different emulating controller.
Here's a Legal CDC9766 (I think) on a Plessey controller that plugged
into an RH70 but didn't use the actual DEC Massbus (probably the CDC A
and B SMD cables... (Storage Module Device? IIRC)
https://books.google.com/books?id=-Nentjp6qSMC&pg=RA1-PA66&dq=eaton…
DEC even took the Emulex controllers on service contract in the late 80's.
Bill
From: Dave
Horsfall<dave(a)horsfall.org>
[ Getting into COFF territory, I think ]
In all fairness, the entire field didn't really appreciate the metastability
issue until the LINC guys at WUSTL did a big investigation of it, and then
started a big campaign to educate everyone about it - it wasn't DEC being
particularly clueless.
Hey, if the DEC marketoids didn't want
3rd-party UNIBUS implementations
then why was it published?
Well, exactly - but it's useful to remember the differening situation for DEC
from 1970 (first PDP-11's) and later.
In 1970 DEC was mostly selling to scientists/engineers, who wanted to hook up
to some lab equipment they'd built, and OEM's, who often wanted to use a mini
to control some value-added gear of their own devising. An open bus was really
necessary for those markets. Which is why the 1970 PDP-11/20 manual goes into
a lot of detail on how to interface to the PDP-11's UNIBUS.
Later, of course, they were in a different business model.
Noel