[rescue] J90 on epay

[Joshua D. Boyd]

On Sat, Mar 01, 2003 at 09:19:11PM -0500, Dave McGuire wrote:

>    The only non-off-the-shelf VME64 board found in J90s is the IOBB 
> interface.  They mainly use Interphase boards.
> 
>    The only direct-attach framebuffers I've ever heard of being 
> connected to a Cray were HIPPI-attached ones.  I'm still looking for 
> one of those.  I missed one on eBay about two years ago, haven't seen 
> one since.

I don't think the console I head of was a HIPPI one, but I could be
wrong.  Although, I don't see why one couldn't use a VME64 framebuffer.

I've heard of HIPPI framebuffers, but I've never seen one.  I get the
impression that they weren't very common, since most of the time I heard 
of a Cray or CM being used for graphics work, it was being connected to
an SGI or Symbolics machine for the display.

Still, a HIPPI network with a Cray J90, a IBM S/390 G5 (database and
file server), a few challenges and Onyxs, and a stand alone frame buffer
or two would rock seriously.
 
> > How much of the machine have you managed to figure out?  Enough of the
> > machine code to be able to make a start of coding ones own OS?
> 
>    All but the specifics of talking over the IOBB interface.
> 
>    There's really not much motivation for putting a different OS on one 
> of those machines, though.  UNICOS is *nice*...and the compilers just 
> can't be beat.
> 
> > I had no idea that HIPPI would be installed as something other than
> > VME64.  Is this for latency reasons, or is VME64 not as fast as I would
> > have expected?  For some reason, I expected that VME64 would be faster
> > than PCI/X.
> 
>    I don't know the spec offhand, but VME64 is *fast*.  I assume it's a 
> latency issue but I'm really not sure.  Possibly a sustained I/O issue.
> 
>    Actually, now that I think about it...HIPPI is usually treated as a 
> network interface with a VERY LARGE MTU.  In fact, there's nothing 
> about HIPPI that requires it to have an MTU at all.  I wonder if the 
> HIPPI-attached-to-the-CPU deal has something to do with swamping the 
> IOBB or the VME64 bus and starving the disk subsystem for DMA cycles.  
> That would seem to make sense.
> 
> > 68020s seem to be used a lot as FEPs.  They are cool little chips.
> 
>    Yes they certainly are. :-)  And being very CISC, GCC actually 
> generates decent code for them.
> 
> > I wish I had more time hack on those older 680x0 machines.
> 
>    Then get a job doing embedded systems development.  68K processors 
> are *all over* the embedded world.  I'm working on a simple DragonBall 
> (MC68VZ328, 68EC000 core) design right now.
> 
>          -Dave
> 
> --
> Dave McGuire             "I've grown hair again, just
> St. Petersburg, FL           for the occasion."       -Doc Shipley
> _______________________________________________
> rescue list - http://www.sunhelp.org/mailman/listinfo/rescue