[Simh] LAVC

[Sergey Oboguev]

Just curious:
Is HSC firmware and software available?(Well, I know someone who has a live system running with HSCshttp://fafner.dyndns.orgtelnet fafner.dyndns.org
so the software for at least *some* HSC models might be retrievable, less sure about the firmware.)

Does there exist a sufficiently detailed hardware spec on the HSC? if yes, which models?

In particular, a description of CI/SC interface from the HSC side?After all, the source code for VMS and BSD is available, so one might hypothetically infer what they expect from CI by reverse-engineering the source code.But what about the J-11 side?

Thanks,Sergey

      From: Johnny Billquist <bqt at softjar.se>
 To: Mark Pizzolato <Mark at infocomm.com>; "simh at trailing-edge.com" <simh at trailing-edge.com> 
 Sent: Saturday, March 11, 2017 1:15 PM
 Subject: Re: [Simh] LAVC
   
On 2017-03-11 19:41, Mark Pizzolato wrote:
> On Saturday, March 11, 2017 at 10:06 AM, Johnny Billquist wrote:
>> On 2017-03-11 17:18, Mark Pizzolato wrote:
>>> On Saturday, March 11, 2017 at 5:49 AM, Tim Stark wrote:
>>>> Thanks for many replies. I learned a lot about VAX clustering. I will
>>>> use multicast Ethernet for clustering.  I have more one question. Is
>>>> that possible to emulate HSC controllers with LAVC access?
>>>
>>> When Matt Burke and I were discussing the CI concept, we picked IP
>>> Multicast as transport for the very specific reason that all modern
>>> host systems will have natural user mode programming access to
>>> implement this functionality.  Attempting to create your own Ethernet
>>> multicast protocol (non-IP based) will have portability complexities
>>> on different platforms due to the fact different platforms have
>>> varying support (and potentially require privilege) to present and/or
>>> receive raw Ethernet frames to/from a LAN.
>>
>> I don't know for sure, but I assume that Tim just meant that he will let LAVC
>> do as LAVC does, without him doing anything.
>> And LAVC itself might be using ethernet multicasting.
>> This is no more an issue than DECnet communication, which also requires
>> access to the raw ethernet.
>
> True.  It could use the existing raw Ethernet access methods, but that approach
> would have the following issues:
>     1) Some platforms require significant privilege (root) to do this.

Same as DECnet.

>     2) He would have to re-invent much of what LAVC does.

I thought he was talking just about LAVC, not inventing something new.

>     3) The same problems that exist today on *nix hosts to provide a
> mechanism for multiple simulators running on the same host to be able to
> concurrently communicate with each other will exist.
>
> An IP multicast based solution lets the host OS solve much of this.

Either you or me is missing something. I thought he was just talking 
about using LAVC (and thus raw ethernet) for clustering. Meaning he'll 
just fire up is simh instance, and start running. And that's the end of it.

Seems like you are thinking he is going to implement something. Not sure 
exactly what. Emulate CI? Possible, but will require a lot more work 
than just transporting the bytes over the network. But, that said, it 
probably makes sense to use IP instead of raw ethernet if you are going 
to implement this. And my reasoning for that don't have as much to do 
with any network access (which you still will want to have for DECnet 
anyhow), but because CI frames are something like 8K in size. So you're 
going to have to implement some kind of complex layer on top of ethernet 
if you do that. And then you are going to get close to what IP/UDP will 
do for you anyhow, so why reinvent the wheel?

    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
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