[Simh] Raspberry Pi VAXcluster [was: Re: HSC vs UDA/QDA]

[Johnny Billquist]

On 2017-03-11 11:58, Wilm Boerhout wrote:
> Paul Koning schreef op 9-3-2017 om 23:59:
>>> On Mar 9, 2017, at 12:15 PM, Mark Pizzolato <Mark at infocomm.com> wrote:
>>>
>>> On Wednesday, March 8, 2017 at 11:50 PM, Johnny Billquist wrote:
>>>> ...
>>> When Matt Burke initially was working on this, I believe that we
>>> talked briefly
>>> about extending sim_ether to support packet delivery across IP
>>> multicast.
>>> With that model, all of the systems connected to a particular star
>>> coupler
>>> would use the same multi-cast group.  I think that DEC may have done
>>> something very similar to this when they implemented LAVC.  Several
>>> independent Local Area VAX Clusters can certainly coexist on the same
>>> LAN without interference.
>> No, LAVC is an Ethernet based protocol (it sits directly on top of
>> Ethernet).  No routing layer, IP or otherwise.
>>
>> You could tunnel it over Johnny's bridge protocol, of course.
>>
>>     paul
>>
> You could have a look at my VAX on Raspberry Pi / SIMH story at
> https://www.linkedin.com/pulse/mixed-architecture-openvms-cluster-wilm-boerhout
>
>
> The LAVC cluster is still running today, and will survive individual
> systems missing (even the one voting member) when I upgrade Raspbian OS
> and/or SIMH itself.

You missed Paul's point.
The initial idea/thought was about emulating CI using IP multicasting. 
That can't be done without some additional glue.
LAVC was then mentioned as if it was done using IP multicasting, similar 
to the suggestion about CI emulated over IP, which was incorrect. LAVC 
is not using IP, and thus cannot use IP multicasting (obviously).

Paul then mentioned my bridge software as a way to connect LAVC machines 
together, even if they are not on the same physical network, which can 
be done.

None of this contradicts, or much even relates to your observation that 
LAVC works, even on an emulated machine. You just have your simh 
instance hooked to a physical ethernet, and LAVC is talking over that 
physical ethernet. No IP involved.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol