[rescue] FDDI in the real world babble

[Jochen Kunz]

On 2002.08.07 17:19 Joshua D Boyd wrote:

> to bring up the concentrator that I have no documentation for, 
What brand / model is it?

> and is not known to be working.
:-/

> Since I want to use NAS anyway, I wonder how a quad 4/600 with VME
> FDDI would perform as a database server. 
Depends on the card. There was the Interpahase 4421 "Peregrine I" VME
FDDI card. I have one. I tried to get it to work in my SGI 4D30 when I
noticed that IRIX has a driver for it, but nogo. Later I was toled that
SGI sold a special verion of that card with hardware patches and an
other firmware to get more throughput out of that card. Normal the card
could do 40 MBit/s, the SGI version reached up to 80 MBit/s. There are
also SunOS 4.x drivers for that card. Sun made a 9U VME FDDI cared too.
The "IO processor" on it looks like a striped down 3/60. :-)

> But then, if I went with sbus FDDI on it, I could use the same VME
chassis
> to bring up a second 4/600 with FDDI for use as an application server.

He, multiple 4/600. Nice. When I swaped the SM40 for the SM61 yesterday
I checked the temperature of the CPU after it run for some time in the
3/60 case. I have to get an other case with _much_ better ventilation...
;-(

> Whatever.  The way
> things are going, it looks like I'll be using a stack of U1s for these
A stack of U1, drool.

> Anyway, what is the name of the software package that is holding up
> FDDI support on NetBSD?  Was it SME? 
SMT, StationManagemenT. http://www.syskonnect.de/syskonnect/technology/c010307_technology.html
FDDI (and so SMT) is an ANSI standard. You can get the specs, but a
proper implementation on that bais is non-trivial. That is The Problem.
AFAIK SysKonnect did a GPLed release of their SMT code so that there are
Linux drivers for the SysKonnect PCI cards. 

> The thing that is implemented in
> hardware on the DEFPAs, but not most other cards? 
Yes. The SGI cards have SMT "on board" too. 

> My understanding is
> that the Cresendo implements this in hardware also, meaning it
> shouldn't be at all CPU hungry.  Or so I was once told.  
No hardware SMT does not mean bad performance. The SysKonnect cards
don't have hardware SMT but they perform very well. (Mr. McGuire can
tell you.) The over all hardware design of that NPI cards seams to be
crap. DECs first try to build a TurboCannel FDDI card was somewhat bad
too. The DEFZA uses PIO (!) for sending data. 
-- 



tsch,
         Jochen

Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/