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

[Wilm Boerhout]

Johnny Billquist schreef op 11-3-2017 om 13:09:
> 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
>
Yes, yes and.. yes. Not trying to contradict anyone. Just another 
showcase example.


/Wilm