[pups] Netcom HV-1148 QBus Backplane

Bill Gunshannon bill at cs.uofs.edu
Thu Oct 24 05:29:19 AEST 2013

> Hi all,
> I am hoping this list is still alive, since I'd like to find out a bit
more info about this backplane.
> It's part of an 11/23 system (based on CPU) that is made by Netcom. It
> standard DEC
> cards in it DLV11, M8021 bootstrap board etc. Apparently the system ran
> few years back
> before it was put in storage.

I have a few Netcom boxes at home.  I'll try to remember to look
at what models when I go home.

>                           I aquired it, in the hopes of bringing it
> back to life and getting
> it to successfully display a login: prompt.

That would depend on the OS more than the hardware.  :-)

> I have read through the archives, esp. a post from Michael Sokolov back
> 98, where he describes
> the different types of QBus'es. Q/Q, Q/CD etc.
> It looks like the backplane that I have (according to some documents
written at SLAC in late 70's)
> is a serpentine or sinusoidal.
> A diagram on the cardcage describes as follows:
> A B C D
> ------------>
> <-----------
> ------------->
> <------------
> There is also a blurb about slot 2/CD being wired differently. Two slots
on the diagram are pre-printed for RL controllers.

There were backplanes like that for the two card RL controller.

> My CPU card is a later rev. D so it can do 22bit addressing. I'd like if
possible to run 22bits, since this would allow
> me at a later time to put in a 11/73 cpu that would run 2.11.

I may be wrong (but I am sure someone here will correct me) but if the
backplane is designed for the two card RL controller I think it will be 18
bit and not capable of 22 bit.

> How would I go about checking if the backplane is wired for 22bits or
> I seem to remeber the standard qbuses had the W1-W4 pins (?)
> that you could wirewrap to change from 18to22, but this backplane has
nothing like that.

I would guess you could look at it and see how many bits are wired thru.
And, if you have a clear view of the wirewrap side you should be able to
see if it has two A-B-C-D slots in the middle.  Difference in wirewrap
pattern will be obvious.  :-)

> Also, in the present configuration, with an 11/23 and 128Kw, could I run
v6 or v7 (assuming I can get some form of supported disk storage)? At
> I only have a floppy controller and a bunch of 8" Shugart 801 drives..

What floppy controller?  Dec didn't use the standard Shugart 8" inteface
for RX01/RX02 disks.  If it is like the Terak which also used 801's you
are going to need to find drivers for what OS you decide to use.  Good
luck with that.

> thanks in advance for any replies.

You might try asking on alt.sys.pdp11 as there are a lot much more
knowlegable people than I active over there.


Bill Gunshannon          |  de-moc-ra-cy (di mok' ra see) n.  Three wolves
bill at cs.scranton.edu     |  and a sheep voting on what's for dinner.
University of Scranton   |
Scranton, Pennsylvania   |         #include <std.disclaimer.h>

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