[rescue] Sun Ultra5 emulation, was: more sun2 adventures!

[JP Hindin]

On Tue, 8 Jan 2019, Sandwich Maker wrote:
> " From: Jonathan Katz <jon at jonworld.com>
> "
> " QEMU will emulate a sparc and you can run the SSP software on anything,
> " even Sparc 5s or 20s.
>
> i conjecture the only limit would be minimum solaris ver, if there is
> one.
>
> " https://wiki.qemu.org/Documentation/Platforms/SPARC
> "
> " When I was a wee lad we were told that the E10Ks just used JTAG and then it
> " was JTAG encapsulated over TCP/IP once the Controllers in the E10K booted
> " far enough and saw the SSPs.
>
> the std setup is with a dedicated ethernet linking the ssp to the big
> iron.  does it have to be dedicated?  and can the ssp box front-end
> for more than one e10k/e25k [at a time], or are things like link ip
> nailed?

As Jonathan pointed out, the E10k has an external SSP, while later 
machines in the series (15k/25k/SunFire 6800s, etc) had internal ones.

To your question, however, there is notes in the documentation 
specifically pointing out that the control is done via encapsulated JTAG 
and the underlying _suggestion_ is that running regular traffic on the 
same network Would Be A Mistake. I've always assumed that the Control 
Board (the board in the E10k with the network interface that passes all 
the requests into the system) was not designed to handle seeing other 
traffic and may do Indeterminate Things when it's seeing packets it's not 
specifically designed to expect.

The SSPs are documented to be paired to a single system. Jonathan 
mentioned hostview handling multiple platforms, however I believe he may 
be mistaken - hostview can handle multiple *domains*, but I don't remember 
ever seeing anything that refers to alternate platforms anywhere.
For reference, a Platform is the Whole Machine (The E10k), and a Domain 
is a subset of the machine that runs a standalone instance of Solaris. A 
Domain has a minimum of one System Board, and a maximum of 16 (the whole 
machine) - so you can run up to 16 domains with 1 System Board each, or 1 
Domain with 16 SBs, or a mix in between.

This being said, I haven't fired my E10k up since March of last year, but 
I'd run it a bunch of times in the prior six months or so (it's on YouTube 
if you have any interest in watching an idiot work out how to use an 
ex-multi-million-dollar super). It's certainly possible I'm forgetting 
something.

> not that i'm ever likely to be faced with the real-life challenge,
> just idle curiosity.

They're still out there, should you wish to be. :)

Thanks again, guys. Really.

  - JP