[Info-vax] DZQ11 on VAX/4000 Model 300

[johnwallace4 at yahoo.co.uk]

On Wednesday, 16 January 2019 00:02:49 UTC, John E. Malmberg  wrote:
> On 1/15/2019 11:34 AM, Michael Moroney wrote:
> > "John E. Malmberg" <wb8tyw at qsl.net_work> writes:
> > 
> >> All devices greater than BIRQ4 should be closer to the CPU than any
> >> serial card, regardless of what the documentation states or you will
> >> eventually get either a bugcheck or machine check.
> > 
> > I never encountered any devices that used other than BIRQ4.
> 
> I have used several.
> 
> >> All Q-bus serial cards that I have seen have a bug in that they only
> >> pass the birq4 related signal from cards after them in the bus.
> > 
> >> Many 3rd party Q-bus disk controllers are BIRQ5.
> > 
> > Was there anything else that did so? Anything from Digital that did so?
> 
> DTQNA and the manual for it stated to put it after the CXYO8 cards. 
> Guaranteed eventual crash.  And the interrupt driver for it did not 
> save/restore R9, which occasionally upset something.
> 
> Regards,
> -John

DTQNA? Amazing (assuming you do mean the 802.4 Token Bus 
adaptor for Qbus, and come to think of it, I do recall some
card positioning weirdness tales at the time, but I may
have assumed that was down to it being a 2card set consisting
of a quad height controller card *plus* a quad height RF 
modem card, to connect to the 802.4 "broadband meaning 
wideband" coax cable). 

I had access to a DTQNA and (QBus) VAX 4000 for a while, 
to play with the associated OMNI/OSAP software, but 
didn't  really have much of a network to connect to it. 

The local GE office had some 802.4 kit, but the local 
Siemens office usually had more interest (given that 
they could achieve much the same result over cheaper and 
more easily deployed 802.3, at least with Siemens PLCs). 

Readers with long memories may have noticed that was a 
long time ago, although the last time I looked for the 
relevant software (DEC/OMNI and DEC/OSAP) on a VSIVMS
roadmap, they were still there and scheduled for release
in 2018. DTQNA? Presumably long gone.