Pdp11 Ethernet cards - test-drb@ccmp.vtda.org

1 Aug 2013

On 2013-08-01 19:00, David Riley<fraveydank at gmail.com> wrote:
...

 On Jul 24, 2013, at 6:55 PM, Roe Peterson<roe at liveblockauctions.com>  wrote:

  >I'm looking to equip my unibus pdp11/34a
and qbus 11/83 with Ethernet cards.  I have no experience with old DEC network hardware,
and I need advice.
 >
 >On the qbus side, what is the difference between a DELNA and DEQNA?   Is one
superior?  Is there a better alternative?  Do you mean DELQA instead of DELNA? The
DELQA was the later Qbus Ethernet
 board that I'm aware of.  It's what I have; it has a 10 MHz 68000 on board,
 which should be plenty for handling heavy Ethernet load.  The older DEQNA
 (which, if I'm not mistaken, is essentially a Qbus version of the DEUNA)
 has power consumption/heat dissipation issues and some lockup issues as
 mentioned before.  The DELQA is generally backwards-compatible with the
 DEQNA for most software, though it has a jumper setting which purports to
 make it 100% backwards-compatible for less tolerant software (all DEC OSes
 supposedly support DELQA in its normal backwards-compatible mode). 
He is most likely talking about the DELQA, yes.

And to clarify a couple of things:
For Unibus you have:
DEUNA - PDP-11-based ethernet controller. 2 cards.
DELUA - 68K-based ethernet controller. 1 card.
For Qbus:
DEQNA - Discrete logic microcode engine. 1 card.
DELQA - 68K based ethernet controller. 1 card.

The Unibus controllers are software compatible. The Qbus controllers are 
software compatible.
However, the Unibus and Qbus controllers have totally different 
programming models, and are not compatible at all. There is not the 
slightest bit of relationship between them.

Anyone thinking that a DEQNA is just a Qbus version of a DEUNA is just 
plain wrong. And the same goes for the DELQA compared to the DELUA.
They are not even close.

The DELQA can operate either in DEQNA compatible mode (controlled by a 
switch) or in DELQA mode, which is different, but not very much so.
There was also a late modification to the DELQA, called the DELQA-Plus, 
or DELQA-YM, which had some extra enhancements to it.

...
  DELQAs usually aren't that hard to find on eBay,
and if you're lucky, they
 come with a cab kit (which isn't that hard to make, since it's a pretty
 straightforward AUI cable with a fuse).  DEQNA cab kits should work fine
 with a DELQA. 
I have definitely used DEQNA cab kits on DELQAs, and I think I have used 
things the other way around as well. Someone mentioned that there is a 1 
wire difference, which I think is correct. Not significant enough to 
affect functionality.

...
  As far as I can tell, the DELUA is the Unibus
equivalent to the DELQA.  In
 general, if you swap a U for a Q in the name, that's what you're looking
 for (which is why if there's something called a DELNA, I don't know what
 it is, but the only picture purporting to be on I can see on Google looks
 an awful lot like a DELQA to me). 
Right, apart from the fact that there is not really anything 
"equivalent" about them.

...
   >As for
unibus, any advice at all would be great.  If it matters, my 11/34a has both cache and
floating point, 128kw memory, but I don't know if there are any operating systems with
tcp/ip that will run on it.  As mentioned above, AFAIK, Unibus has DEUNA and DELUA,
of which the latter
 is the preferred model.  No idea how hard it is to come across that.  For
 TCP/IP, I know Johnny Bilquist has a stack for RSX-11M+, but that won't
 run on 128kW of RAM.  TCP/IP is a bit of a tall order for a PDP-11, but
 DECNET isn't, and Linux still works more or less fine with it. 
TCP/IP isn't really such a big problem either. It's not worse than 
DECnet. However, for various reasons I have chosed to write it 
explicitly only for M+. There is a commercial TCP/IP that works on 11M 
as well, and that is TCPware.
Linux DECnet do not work well at all with RSX DECnet, in my experience. :-(

...
  Speaking of: can anyone guide me as to how I should go
about installing
 DECNET on RSX-11M (not plus) 4.6?  I'm having a hard time figuring out
 which (if any) of the available images online will work for that version.
 The tape images seem a bit hard to come by, and I've periodically scoured
 Google looking for anything.  Part of the problem is that I'm not as
 familiar with the DECNET versioning system relative to the RSX one, so I
 don't know what's compatible with what. 
Isn't the manuals around? Anyway, it's much more of a headache than 
under 11M. You need to create various regions for DECnet to live in, and 
you need to figure the sizes of these. Fiddly, but not really that hard 
if you know what you are doing and/or have the documentation.

	Johnny